Factors That Influence Retention Duration

Factors That Influence Retention Duration

* Maintaining the corrected tooth alignment achieved during braces.

Okay, so we're talking about how long your teeth stay straight after braces, right? A big piece of that puzzle is how well you, the patient, actually follow those instructions about wearing your retainer. I mean, it sounds simple enough: wear it as directed, and your teeth are probably going to stay where they're supposed to. Orthodontic check-ups help track the progress of tooth movement Children's braces treatment pediatric dentistry. But life happens, doesn't it?


Think about it. If your orthodontist says wear it full-time for six months, then only at night, and you're only wearing it a couple of nights a week... well, those teeth are going to start shifting. Compliance, or sticking to the plan, is huge. It's not just about remembering to wear it, either. It's about cleaning it properly, storing it safely so you don't lose or break it, and even communicating with your orthodontist if it's uncomfortable or doesn't fit right anymore.


Why is it so hard? Lots of reasons. Maybe you find the retainer uncomfortable, especially at first. Maybe you're self-conscious about wearing it during the day. Maybe you just plain forget. But think of all the time, effort, and money you invested in getting straight teeth. Sticking to the retainer schedule is the best way to protect that investment. Ultimately, the success of retention, and how long your smile stays perfect, rests heavily on your commitment to wearing that retainer as instructed. It's truly the final, and arguably most important, step in the whole orthodontic process.

Okay, so when we're talking about how long you'll need to wear your retainers after braces, one of the big factors is the type and severity of the malocclusion – basically, how messed up your teeth were to begin with. Think of it like this: the more complicated the puzzle, the more careful you have to be to keep it solved.


A mild crowding issue might be relatively quick to stabilize after treatment. Your teeth didn't have to move that far, and the surrounding tissues probably adapted pretty easily. But if you started with a severe overbite, a significant open bite, or teeth that were rotated way out of whack, things get trickier. These more complex cases often involve significant changes to the bone surrounding the teeth, the muscles in your face, and even the way you bite. That's a lot of stuff that needs to settle down and stay put.


The more dramatic the original problem, the greater the tendency for the teeth to want to shift back toward their old positions. Imagine stretching a rubber band really far – it's got a lot of stored energy and wants to snap back. Similarly, teeth that have been moved a long distance are more likely to relapse. So, a more severe initial malocclusion often translates to a longer, and maybe even a lifetime, commitment to retention to keep everything nice and straight. It's not a punishment, just a recognition that some smiles need a little extra help to stay beautiful.

* Protecting the investment made in orthodontic treatment.

Okay, so we've straightened those pearly whites, shifted those bites into perfect harmony, and everyone's flashing a confident smile. But here's the thing about orthodontics: it's not a "one and done" deal. Retention is key, and how long that retention needs to last is where things get interesting. One of the big factors influencing retention duration? It's all about growth and development following orthodontic treatment.


Think of it like this. If a teenager finishes braces at 15, they're still growing. Their jaws are still changing, teeth are still settling, and that last growth spurt could nudge things around. This means that the initial orthodontic alignment is potentially vulnerable. We might need a longer retention period – maybe a permanent retainer on some teeth, or consistent nighttime wear of a removable retainer – to guide that final growth and make sure those teeth stay put. We're essentially trying to shepherd the teeth through those final developmental phases.


On the other hand, an adult who completes orthodontic treatment might be more stable, growth-wise. Their skeletal structure has matured, and the forces of growth are less likely to cause relapse. In these cases, maybe a shorter retention period is sufficient, or perhaps a less intensive retention protocol.


The point is, it's not a one-size-fits-all situation. The orthodontist needs to consider how much remaining growth is anticipated, and how that growth might impact the newly aligned teeth. It's a bit like predicting the weather – we can look at past patterns and current conditions to make an educated guess about what might happen. The more growth that's expected, the more diligent we need to be with retention, making sure those smiles stay beautiful for the long haul.

* Protecting the investment made in orthodontic treatment.

* Ensuring the long-term stability of the bite and smile.

Okay, so you've finally got your braces off. Congratulations! All that time, money, and occasional discomfort have paid off with a beautifully aligned smile. But here's the thing: keeping it that way isn't a given. We need to talk about the stability of that achieved orthodontic correction. Think of it like this: your teeth have memory. They've been nudged into new positions, and they might just try to drift back to where they started.


The stability of your orthodontic result – basically, how likely it is to stay put – is a really big deal. It's not just about aesthetics; it's about long-term function and health. A relapse, where teeth shift, can lead to problems with your bite, jaw pain, and even increased risk of gum disease.


Now, there are a bunch of things that play a role in how stable your teeth are after treatment. How well your teeth fit together after the braces come off is crucial. If your bite still has some issues, like a deep overbite or a crossbite, the forces of chewing and jaw movement can push your teeth out of alignment. Think of it like trying to balance something on an uneven surface – it's just not going to stay put for long.


Then there's the soft tissue factor. Your lips, cheeks, and tongue all exert pressure on your teeth. If these pressures are imbalanced, they can cause teeth to shift. Tongue thrusting, for instance, where you push your tongue against your teeth when you swallow, can be a real culprit.


Growth is another big one, especially for younger patients. Our faces continue to grow and change well into adulthood, and this growth can sometimes affect the alignment of our teeth. That's why some people might need further minor adjustments later in life, even after having braces in their teens.


Finally, habits matter. Things like thumb sucking or nail biting can put pressure on your teeth and cause them to move. And of course, wearing your retainers religiously is absolutely key to maintaining that beautiful smile! It's a commitment, but it's worth it to protect your investment and enjoy the benefits of a properly aligned bite for years to come. So, listen to your orthodontist, wear your retainers, and be mindful of your habits – that's the recipe for long-term stability.

* Supporting proper jaw growth and development in younger children.

Okay, so picture this: you've just gotten your braces off, and you're beaming. That perfect smile is finally here! But the journey isn't quite over. You've entered the retention phase, and how well you take care of your mouth now can seriously impact how long that retainer stays in, and more importantly, how long your teeth stay put. We're talking about oral hygiene and periodontal health, which basically means keeping your gums and teeth squeaky clean and healthy.


Think of it like this: if you're not brushing and flossing religiously, plaque and bacteria are going to build up. This can lead to gingivitis, which is inflammation of the gums. Left unchecked, gingivitis can turn into periodontitis, a more serious infection that can eventually lead to bone loss around your teeth. Now, imagine trying to hold teeth in their new, perfectly aligned positions when the underlying support structure – your gums and bone – is compromised. It's like trying to build a house on a shaky foundation.


Poor oral hygiene and periodontal disease can actually cause teeth to shift and move, even with a retainer in place. This is because the inflammation and bone loss weaken the support around the teeth, making them more susceptible to relapse. Plus, inflamed gums can make wearing a retainer uncomfortable, leading to inconsistent wear, which, you guessed it, increases the risk of your teeth moving back to their old positions.


So, really, good oral hygiene isn't just about having a pretty smile; it's fundamentally linked to the success and duration of your retention phase. Diligent brushing, flossing, regular dental checkups, and professional cleanings will keep your gums healthy, your teeth stable, and your retainer doing its job effectively. Neglecting these things? Well, you might be looking at a longer retention period, or even needing further orthodontic treatment down the line. It's definitely worth putting in the effort to keep that hard-earned smile looking its best, and staying that way!

* Avoiding the need for future, potentially more extensive, orthodontic intervention.

Factors That Influence Retention Duration: Choice of Retainer Type (Removable vs. Fixed)


Choosing between removable and fixed retainers isn't just about convenience; it significantly impacts how long you'll need to wear them. Think of it like this: a removable retainer, often a clear aligner or Hawley retainer, is like a part-time job for your teeth. It's effective when you're diligent about wearing it as prescribed. However, consistency is key. If you're prone to forgetting or simply slacking off, the teeth can gradually shift back, necessitating a longer overall retention period, or even requiring further orthodontic intervention. The success of removable retainers hinges heavily on patient compliance.


Fixed retainers, on the other hand, act like a permanent security guard for your teeth. They're bonded to the back surfaces of your front teeth, typically the lower ones, and provide continuous retention without relying on your memory or motivation. Because they're always in place, they can be particularly effective at preventing relapse, especially rotation of the lower incisors, a common issue after orthodontic treatment. This constant support can potentially shorten the overall retention duration needed, or at least ensure stability during a crucial initial period. However, fixed retainers require meticulous oral hygiene to prevent plaque buildup and gum disease, and they may be more prone to breakage, requiring repair or replacement.


Ultimately, the choice between removable and fixed retainers, and therefore the potential duration of retention, is a balancing act. It depends on the specific orthodontic issues addressed, the patient's commitment to following instructions, and their ability to maintain excellent oral hygiene. Your orthodontist will weigh these factors carefully to recommend the most appropriate retainer type and retention protocol for your individual needs, aiming for long-term stability and a confident, lasting smile.

* Contributing to overall oral health by preventing crowding and misalignment.

Okay, so we're talking about retention after orthodontic treatment, and one of the things that really impacts how long teeth stay put is how well your muscles and nerves get used to the new bite. We call that "neuromuscular adaptation to the corrected occlusion." Sounds fancy, right? Basically, it means your jaw muscles, your tongue, and all the little sensors that tell your brain where your teeth are, need to get on board with the changes braces or aligners made.


Think about it: for months, maybe even years, your muscles were pulling your teeth in a certain way, used to a very specific bite. Then, BAM! Orthodontics comes along and shifts everything. Your muscles are still programmed to pull in the old direction. That's why relapse happens. So, the longer it takes for those muscles and nerves to rewire themselves and accept the new tooth positions as "normal," the greater the chance your teeth will try to wander back.


This adaptation isn't just about muscles getting stronger or weaker. It's about the whole system learning a new pattern. It involves the brain learning a new way to coordinate chewing, speaking, and even just resting your jaw. The better this learning process goes, the more stable your results will be. That's why some orthodontists recommend exercises to help retrain these muscles, or use retainers that encourage proper tongue posture.


Ultimately, neuromuscular adaptation is a slow burn. It doesn't happen overnight. It's a gradual process that needs time and consistency. That's why wearing your retainer as instructed is so crucial. It gives your muscles and nerves the constant feedback they need to solidify those new pathways and keep your smile where it belongs. If the neuromuscular system doesn't fully adapt, the forces will remain unbalanced and retention duration will be greatly impacted.

Orthodontics
Connecting the arch-wire on brackets with wire
Occupation
Names Orthodontist
Occupation type
Specialty
Activity sectors
Dentistry
Description
Education required
Dental degree, specialty training
Fields of
employment
Private practices, hospitals

Orthodontics[a][b] is a dentistry specialty that addresses the diagnosis, prevention, management, and correction of mal-positioned teeth and jaws, as well as misaligned bite patterns.[2] It may also address the modification of facial growth, known as dentofacial orthopedics.

Abnormal alignment of the teeth and jaws is very common. The approximate worldwide prevalence of malocclusion was as high as 56%.[3] However, conclusive scientific evidence for the health benefits of orthodontic treatment is lacking, although patients with completed treatment have reported a higher quality of life than that of untreated patients undergoing orthodontic treatment.[4][5] The main reason for the prevalence of these malocclusions is diets with less fresh fruit and vegetables and overall softer foods in childhood, causing smaller jaws with less room for the teeth to erupt.[6] Treatment may require several months to a few years and entails using dental braces and other appliances to gradually adjust tooth position and jaw alignment. In cases where the malocclusion is severe, jaw surgery may be incorporated into the treatment plan. Treatment usually begins before a person reaches adulthood, insofar as pre-adult bones may be adjusted more easily before adulthood.

History

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Though it was rare until the Industrial Revolution,[7] there is evidence of the issue of overcrowded, irregular, and protruding teeth afflicting individuals. Evidence from Greek and Etruscan materials suggests that attempts to treat this disorder date back to 1000 BC, showcasing primitive yet impressively well-crafted orthodontic appliances. In the 18th and 19th centuries, a range of devices for the "regulation" of teeth were described by various dentistry authors who occasionally put them into practice.[8] As a modern science, orthodontics dates back to the mid-1800s.[9] The field's influential contributors include Norman William Kingsley[9] (1829–1913) and Edward Angle[10] (1855–1930). Angle created the first basic system for classifying malocclusions, a system that remains in use today.[9]

Beginning in the mid-1800s, Norman Kingsley published Oral Deformities, which is now credited as one of the first works to begin systematically documenting orthodontics. Being a major presence in American dentistry during the latter half of the 19th century, not only was Kingsley one of the early users of extraoral force to correct protruding teeth, but he was also one of the pioneers for treating cleft palates and associated issues. During the era of orthodontics under Kingsley and his colleagues, the treatment was focused on straightening teeth and creating facial harmony. Ignoring occlusal relationships, it was typical to remove teeth for a variety of dental issues, such as malalignment or overcrowding. The concept of an intact dentition was not widely appreciated in those days, making bite correlations seem irrelevant.[8]

In the late 1800s, the concept of occlusion was essential for creating reliable prosthetic replacement teeth. This idea was further refined and ultimately applied in various ways when dealing with healthy dental structures as well. As these concepts of prosthetic occlusion progressed, it became an invaluable tool for dentistry.[8]

It was in 1890 that the work and impact of Dr. Edwards H. Angle began to be felt, with his contribution to modern orthodontics particularly noteworthy. Initially focused on prosthodontics, he taught in Pennsylvania and Minnesota before directing his attention towards dental occlusion and the treatments needed to maintain it as a normal condition, thus becoming known as the "father of modern orthodontics".[8]

By the beginning of the 20th century, orthodontics had become more than just the straightening of crooked teeth. The concept of ideal occlusion, as postulated by Angle and incorporated into a classification system, enabled a shift towards treating malocclusion, which is any deviation from normal occlusion.[8] Having a full set of teeth on both arches was highly sought after in orthodontic treatment due to the need for exact relationships between them. Extraction as an orthodontic procedure was heavily opposed by Angle and those who followed him. As occlusion became the key priority, facial proportions and aesthetics were neglected. To achieve ideal occlusals without using external forces, Angle postulated that having perfect occlusion was the best way to gain optimum facial aesthetics.[8]

With the passing of time, it became quite evident that even an exceptional occlusion was not suitable when considered from an aesthetic point of view. Not only were there issues related to aesthetics, but it usually proved impossible to keep a precise occlusal relationship achieved by forcing teeth together over extended durations with the use of robust elastics, something Angle and his students had previously suggested. Charles Tweed[11] in America and Raymond Begg[12] in Australia (who both studied under Angle) re-introduced dentistry extraction into orthodontics during the 1940s and 1950s so they could improve facial esthetics while also ensuring better stability concerning occlusal relationships.[13]

In the postwar period, cephalometric radiography[14] started to be used by orthodontists for measuring changes in tooth and jaw position caused by growth and treatment.[15] The x-rays showed that many Class II and III malocclusions were due to improper jaw relations as opposed to misaligned teeth. It became evident that orthodontic therapy could adjust mandibular development, leading to the formation of functional jaw orthopedics in Europe and extraoral force measures in the US. These days, both functional appliances and extraoral devices are applied around the globe with the aim of amending growth patterns and forms. Consequently, pursuing true, or at least improved, jaw relationships had become the main objective of treatment by the mid-20th century.[8]

At the beginning of the twentieth century, orthodontics was in need of an upgrade. The American Journal of Orthodontics was created for this purpose in 1915; before it, there were no scientific objectives to follow, nor any precise classification system and brackets that lacked features.[16]

Until the mid-1970s, braces were made by wrapping metal around each tooth.[9] With advancements in adhesives, it became possible to instead bond metal brackets to the teeth.[9]

In 1972, Lawrence F. Andrews gave an insightful definition of the ideal occlusion in permanent teeth. This has had meaningful effects on orthodontic treatments that are administered regularly,[16] and these are: 1. Correct interarchal relationships 2. Correct crown angulation (tip) 3. Correct crown inclination (torque) 4. No rotations 5. Tight contact points 6. Flat Curve of Spee (0.0–2.5 mm),[17] and based on these principles, he discovered a treatment system called the straight-wire appliance system, or the pre-adjusted edgewise system. Introduced in 1976, Larry Andrews' pre-adjusted edgewise appliance, more commonly known as the straight wire appliance, has since revolutionized fixed orthodontic treatment. The advantage of the design lies in its bracket and archwire combination, which requires only minimal wire bending from the orthodontist or clinician. It's aptly named after this feature: the angle of the slot and thickness of the bracket base ultimately determine where each tooth is situated with little need for extra manipulation.[18][19][20]

Prior to the invention of a straight wire appliance, orthodontists were utilizing a non-programmed standard edgewise fixed appliance system, or Begg's pin and tube system. Both of these systems employed identical brackets for each tooth and necessitated the bending of an archwire in three planes for locating teeth in their desired positions, with these bends dictating ultimate placements.[18]

Evolution of the current orthodontic appliances

[edit]

When it comes to orthodontic appliances, they are divided into two types: removable and fixed. Removable appliances can be taken on and off by the patient as required. On the other hand, fixed appliances cannot be taken off as they remain bonded to the teeth during treatment.

Fixed appliances

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Fixed orthodontic appliances are predominantly derived from the edgewise appliance approach, which typically begins with round wires before transitioning to rectangular archwires for improving tooth alignment. These rectangluar wires promote precision in the positioning of teeth following initial treatment. In contrast to the Begg appliance, which was based solely on round wires and auxiliary springs, the Tip-Edge system emerged in the early 21st century. This innovative technology allowed for the utilization of rectangular archwires to precisely control tooth movement during the finishing stages after initial treatment with round wires. Thus, almost all modern fixed appliances can be considered variations on this edgewise appliance system.

Early 20th-century orthodontist Edward Angle made a major contribution to the world of dentistry. He created four distinct appliance systems that have been used as the basis for many orthodontic treatments today, barring a few exceptions. They are E-arch, pin and tube, ribbon arch, and edgewise systems.

E-arch

[edit]

Edward H. Angle made a significant contribution to the dental field when he released the 7th edition of his book in 1907, which outlined his theories and detailed his technique. This approach was founded upon the iconic "E-Arch" or 'the-arch' shape as well as inter-maxillary elastics.[21] This device was different from any other appliance of its period as it featured a rigid framework to which teeth could be tied effectively in order to recreate an arch form that followed pre-defined dimensions.[22] Molars were fitted with braces, and a powerful labial archwire was positioned around the arch. The wire ended in a thread, and to move it forward, an adjustable nut was used, which allowed for an increase in circumference. By ligation, each individual tooth was attached to this expansive archwire.[8]

Pin and tube appliance

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Due to its limited range of motion, Angle was unable to achieve precise tooth positioning with an E-arch. In order to bypass this issue, he started using bands on other teeth combined with a vertical tube for each individual tooth. These tubes held a soldered pin, which could be repositioned at each appointment in order to move them in place.[8] Dubbed the "bone-growing appliance", this contraption was theorized to encourage healthier bone growth due to its potential for transferring force directly to the roots.[23] However, implementing it proved troublesome in reality.

Ribbon arch

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Realizing that the pin and tube appliance was not easy to control, Angle developed a better option, the ribbon arch, which was much simpler to use. Most of its components were already prepared by the manufacturer, so it was significantly easier to manage than before. In order to attach the ribbon arch, the occlusal area of the bracket was opened. Brackets were only added to eight incisors and mandibular canines, as it would be impossible to insert the arch into both horizontal molar tubes and the vertical brackets of adjacent premolars. This lack of understanding posed a considerable challenge to dental professionals; they were unable to make corrections to an excessive Spee curve in bicuspid teeth.[24] Despite the complexity of the situation, it was necessary for practitioners to find a resolution. Unparalleled to its counterparts, what made the ribbon arch instantly popular was that its archwire had remarkable spring qualities and could be utilized to accurately align teeth that were misaligned. However, a major drawback of this device was its inability to effectively control root position since it did not have enough resilience to generate the torque movements required for setting roots in their new place.[8]

Edgewise appliance

[edit]

In an effort to rectify the issues with the ribbon arch, Angle shifted the orientation of its slot from vertical, instead making it horizontal. In addition, he swapped out the wire and replaced it with a precious metal wire that was rotated by 90 degrees in relation—henceforth known as Edgewise.[25] Following extensive trials, it was concluded that dimensions of 22 × 28 mils were optimal for obtaining excellent control over crown and root positioning across all three planes of space.[26] After debuting in 1928, this appliance quickly became one of the mainstays for multibanded fixed therapy, although ribbon arches continued to be utilized for another decade or so beyond this point too.[8]

Labiolingual

[edit]

Prior to Angle, the idea of fitting attachments on individual teeth had not been thought of, and in his lifetime, his concern for precisely positioning each tooth was not highly appraised. In addition to using fingersprings for repositioning teeth with a range of removable devices, two main appliance systems were very popular in the early part of the 20th century. Labiolingual appliances use bands on the first molars joined with heavy lingual and labial archwires affixed with soldered fingersprings to shift single teeth.

Twin wire

[edit]

Utilizing bands around both incisors and molars, a twin-wire appliance was designed to provide alignment between these teeth. Constructed with two 10-mil steel archwires, its delicate features were safeguarded by lengthy tubes stretching from molars towards canines. Despite its efforts, it had limited capacity for movement without further modifications, rendering it obsolete in modern orthodontic practice.

Begg's Appliance

[edit]

Returning to Australia in the 1920s, the renowned orthodontist, Raymond Begg, applied his knowledge of ribbon arch appliances, which he had learned from the Angle School. On top of this, Begg recognized that extracting teeth was sometimes vital for successful outcomes and sought to modify the ribbon arch appliance to provide more control when dealing with root positioning. In the late 1930s, Begg developed his adaptation of the appliance, which took three forms. Firstly, a high-strength 16-mil round stainless steel wire replaced the original precious metal ribbon arch. Secondly, he kept the same ribbon arch bracket but inverted it so that it pointed toward the gums instead of away from them. Lastly, auxiliary springs were added to control root movement. This resulted in what would come to be known as the Begg Appliance. With this design, friction was decreased since contact between wire and bracket was minimal, and binding was minimized due to tipping and uprighting being used for anchorage control, which lessened contact angles between wires and corners of the bracket.

Tip-Edge System

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Begg's influence is still seen in modern appliances, such as Tip-Edge brackets. This type of bracket incorporates a rectangular slot cutaway on one side to allow for crown tipping with no incisal deflection of an archwire, allowing teeth to be tipped during space closure and then uprighted through auxiliary springs or even a rectangular wire for torque purposes in finishing. At the initial stages of treatment, small-diameter steel archwires should be used when working with Tip-Edge brackets.

Contemporary edgewise systems

[edit]

Throughout time, there has been a shift in which appliances are favored by dentists. In particular, during the 1960s, when it was introduced, the Begg appliance gained wide popularity due to its efficiency compared to edgewise appliances of that era; it could produce the same results with less investment on the dentist's part. Nevertheless, since then, there have been advances in technology and sophistication in edgewise appliances, which led to the opposite conclusion: nowadays, edgewise appliances are more efficient than the Begg appliance, thus explaining why it is commonly used.

Automatic rotational control

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At the beginning, Angle attached eyelets to the edges of archwires so that they could be held with ligatures and help manage rotations. Now, however, no extra ligature is needed due to either twin brackets or single brackets that have added wings touching underneath the wire (Lewis or Lang brackets). Both types of brackets simplify the process of obtaining moments that control movements along a particular plane of space.

Alteration in bracket slot dimensions

[edit]

In modern dentistry, two types of edgewise appliances exist: the 18- and 22-slot varieties. While these appliances are used differently, the introduction of a 20-slot device with more precise features has been considered but not pursued yet.[27]

Straight-wire bracket prescriptions

[edit]

Rather than rely on the same bracket for all teeth, L.F. Andrews found a way to make different brackets for each tooth in the 1980s, thanks to the increased convenience of bonding.[28] This adjustment enabled him to avoid having multiple bends in archwires that would have been needed to make up for variations in tooth anatomy. Ultimately, this led to what was termed a "straight-wire appliance" system – an edgewise appliance that greatly enhanced its efficiency.[29] The modern edgewise appliance has slightly different construction than the original one. Instead of relying on faciolingual bends to accommodate variations among teeth, each bracket has a correspondingly varying base thickness depending on the tooth it is intended for. However, due to individual differences between teeth, this does not completely eliminate the need for compensating bends.[30] Accurately placing the roots of many teeth requires angling brackets in relation to the long axis of the tooth. Traditionally, this mesiodistal root positioning necessitated using second-order, or tip, bends along the archwire. However, angling the bracket or bracket slot eliminates this need for bends.

Given the discrepancies in inclination of facial surfaces across individual teeth, placing a twist, otherwise known as third-order or torque bends, into segments of each rectangular archwire was initially required with the edgewise appliance. These bends were necessary for all patients and wires, not just to avoid any unintentional movement of suitably placed teeth or when moving roots facially or lingually. Angulation of either brackets or slots can minimize the need for second-order or tip bends on archwires. Contemporary edgewise appliances come with brackets designed to adjust for any facial inclinations, thereby eliminating or reducing any third-order bends. These brackets already have angulation and torque values built in so that each rectangluar archwire can be contorted to form a custom fit without inadvertently shifting any correctly positioned teeth. Without bracket angulation and torque, second-order or tip bends would still be required on each patient's archwire.

Methods

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Upper and lower jaw functional expanders

A typical treatment for incorrectly positioned teeth (malocclusion) takes from one to two years, with braces being adjusted every four to 10 weeks by orthodontists,[31] while university-trained dental specialists are versed in the prevention, diagnosis, and treatment of dental and facial irregularities. Orthodontists offer a wide range of treatment options to straighten crooked teeth, fix irregular bites, and align the jaws correctly.[32] There are many ways to adjust malocclusion. In growing patients, there are more options to treat skeletal discrepancies, either by promoting or restricting growth using functional appliances, orthodontic headgear, or a reverse pull facemask. Most orthodontic work begins in the early permanent dentition stage before skeletal growth is completed. If skeletal growth has completed, jaw surgery is an option. Sometimes teeth are extracted to aid the orthodontic treatment (teeth are extracted in about half of all the cases, most commonly the premolars).[33]

Orthodontic therapy may include the use of fixed or removable appliances. Most orthodontic therapy is delivered using appliances that are fixed in place,[34] for example, braces that are adhesively bonded to the teeth. Fixed appliances may provide greater mechanical control of the teeth; optimal treatment outcomes are improved by using fixed appliances.

Fixed appliances may be used, for example, to rotate teeth if they do not fit the arch shape of the other teeth in the mouth, to adjust multiple teeth to different places, to change the tooth angle of teeth, or to change the position of a tooth's root. This treatment course is not preferred where a patient has poor oral hygiene, as decalcification, tooth decay, or other complications may result. If a patient is unmotivated (insofar as treatment takes several months and requires commitment to oral hygiene), or if malocclusions are mild.

The biology of tooth movement and how advances in gene therapy and molecular biology technology may shape the future of orthodontic treatment.[35]

Braces

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Dental braces

Braces are usually placed on the front side of the teeth, but they may also be placed on the side facing the tongue (called lingual braces). Brackets made out of stainless steel or porcelain are bonded to the center of the teeth using an adhesive. Wires are placed in a slot in the brackets, which allows for controlled movement in all three dimensions.

Apart from wires, forces can be applied using elastic bands,[36] and springs may be used to push teeth apart or to close a gap. Several teeth may be tied together with ligatures, and different kinds of hooks can be placed to allow for connecting an elastic band.[37][36]

Clear aligners are an alternative to braces, but insufficient evidence exists to determine their effectiveness.[38]

Treatment duration

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The time required for braces varies from person to person as it depends on the severity of the problem, the amount of room available, the distance the teeth must travel, the health of the teeth, gums, and supporting bone, and how closely the patient follows instructions. On average, however, once the braces are put on, they usually remain in place for one to three years. After braces are removed, most patients will need to wear a retainer all the time for the first six months, then only during sleep for many years.[39]

Headgear

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Orthodontic headgear, sometimes referred to as an "extra-oral appliance", is a treatment approach that requires the patient to have a device strapped onto their head to help correct malocclusion—typically used when the teeth do not align properly. Headgear is most often used along with braces or other orthodontic appliances. While braces correct the position of teeth, orthodontic headgear—which, as the name suggests, is worn on or strapped onto the patient's head—is most often added to orthodontic treatment to help alter the alignment of the jaw, although there are some situations in which such an appliance can help move teeth, particularly molars.

Full orthodontic headgear with headcap, fitting straps, facebow, and elastics

Whatever the purpose, orthodontic headgear works by exerting tension on the braces via hooks, a facebow, coils, elastic bands, metal orthodontic bands, and other attachable appliances directly into the patient's mouth. It is most effective for children and teenagers because their jaws are still developing and can be easily manipulated. (If an adult is fitted with headgear, it is usually to help correct the position of teeth that have shifted after other teeth have been extracted.) Thus, headgear is typically used to treat a number of jaw alignment or bite problems, such as overbite and underbite.[40]

Palatal expansion

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Palatal expansion can be best achieved using a fixed tissue-borne appliance. Removable appliances can push teeth outward but are less effective at maxillary sutural expansion. The effects of a removable expander may look the same as they push teeth outward, but they should not be confused with actually expanding the palate. Proper palate expansion can create more space for teeth as well as improve both oral and nasal airflow.[41]

Jaw surgery

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Jaw surgery may be required to fix severe malocclusions.[42] The bone is broken during surgery and stabilized with titanium (or bioresorbable) plates and screws to allow for healing to take place.[43] After surgery, regular orthodontic treatment is used to move the teeth into their final position.[44]

During treatment

[edit]

To reduce pain during the orthodontic treatment, low-level laser therapy (LLLT), vibratory devices, chewing adjuncts, brainwave music, or cognitive behavioral therapy can be used. However, the supporting evidence is of low quality, and the results are inconclusive.[45]

Post treatment

[edit]

After orthodontic treatment has been completed, there is a tendency for teeth to return, or relapse, back to their pre-treatment positions. Over 50% of patients have some reversion to pre-treatment positions within 10 years following treatment.[46] To prevent relapse, the majority of patients will be offered a retainer once treatment has been completed and will benefit from wearing their retainers. Retainers can be either fixed or removable.

Removable retainers

[edit]

Removable retainers are made from clear plastic, and they are custom-fitted for the patient's mouth. It has a tight fit and holds all of the teeth in position. There are many types of brands for clear retainers, including Zendura Retainer, Essix Retainer, and Vivera Retainer.[47] A Hawley retainer is also a removable orthodontic appliance made from a combination of plastic and metal that is custom-molded to fit the patient's mouth. Removable retainers will be worn for different periods of time, depending on the patient's need to stabilize the dentition.[48]

Fixed retainers

[edit]

Fixed retainers are a simple wire fixed to the tongue-facing part of the incisors using dental adhesive and can be specifically useful to prevent rotation in incisors. Other types of fixed retainers can include labial or lingual braces, with brackets fixed to the teeth.[48]

Clear aligners

[edit]

Clear aligners are another form of orthodontics commonly used today, involving removable plastic trays. There has been controversy about the effectiveness of aligners such as Invisalign or Byte; some consider them to be faster and more freeing than the alternatives.[49]

Training

[edit]

There are several specialty areas in dentistry, but the specialty of orthodontics was the first to be recognized within dentistry.[50] Specifically, the American Dental Association recognized orthodontics as a specialty in the 1950s.[50] Each country has its own system for training and registering orthodontic specialists.

Australia

[edit]

In Australia, to obtain an accredited three-year full-time university degree in orthodontics, one will need to be a qualified dentist (complete an AHPRA-registered general dental degree) with a minimum of two years of clinical experience. There are several universities in Australia that offer orthodontic programs: the University of Adelaide, the University of Melbourne, the University of Sydney, the University of Queensland, the University of Western Australia, and the University of Otago.[51] Orthodontic courses are accredited by the Australian Dental Council and reviewed by the Australian Society of Orthodontists (ASO). Prospective applicants should obtain information from the relevant institution before applying for admission.[52] After completing a degree in orthodontics, specialists are required to be registered with the Australian Health Practitioner Regulation Agency (AHPRA) in order to practice.[53][54]

Bangladesh

[edit]

Dhaka Dental College in Bangladesh is one of the many schools recognized by the Bangladesh Medical and Dental Council (BM&DC) that offer post-graduation orthodontic courses.[55][56] Before applying to any post-graduation training courses, an applicant must have completed the Bachelor of Dental Surgery (BDS) examination from any dental college.[55] After application, the applicant must take an admissions test held by the specific college.[55] If successful, selected candidates undergo training for six months.[57]

Canada

[edit]

In Canada, obtaining a dental degree, such as a Doctor of Dental Surgery (DDS) or Doctor of Medical Dentistry (DMD), would be required before being accepted by a school for orthodontic training.[58] Currently, there are 10 schools in the country offering the orthodontic specialty.[58] Candidates should contact the individual school directly to obtain the most recent pre-requisites before entry.[58] The Canadian Dental Association expects orthodontists to complete at least two years of post-doctoral, specialty training in orthodontics in an accredited program after graduating from their dental degree.

United States

[edit]

Similar to Canada, there are several colleges and universities in the United States that offer orthodontic programs. Every school has a different enrollment process, but every applicant is required to have graduated with a DDS or DMD from an accredited dental school.[59][60] Entrance into an accredited orthodontics program is extremely competitive and begins by passing a national or state licensing exam.[61]

The program generally lasts for two to three years, and by the final year, graduates are required to complete the written American Board of Orthodontics (ABO) exam.[61] This exam is also broken down into two components: a written exam and a clinical exam.[61] The written exam is a comprehensive exam that tests for the applicant's knowledge of basic sciences and clinical concepts.[61] The clinical exam, however, consists of a Board Case Oral Examination (BCOE), a Case Report Examination (CRE), and a Case Report Oral Examination (CROE).[61] Once certified, certification must then be renewed every ten years.[61] Orthodontic programs can award a Master of Science degree, a Doctor of Science degree, or a Doctor of Philosophy degree, depending on the school and individual research requirements.[62]

United Kingdom

[edit]

Throughout the United Kingdom, there are several Orthodontic Specialty Training Registrar posts available.[63] The program is full-time for three years, and upon completion, trainees graduate with a degree at the Masters or Doctorate level.[63] Training may take place within hospital departments that are linked to recognized dental schools.[63] Obtaining a Certificate of Completion of Specialty Training (CCST) allows an orthodontic specialist to be registered under the General Dental Council (GDC).[63] An orthodontic specialist can provide care within a primary care setting, but to work at a hospital as an orthodontic consultant, higher-level training is further required as a post-CCST trainee.[63] To work within a university setting as an academic consultant, completing research toward obtaining a Ph.D. is also required.[63]

See also

[edit]
  • Orthodontic technology
  • Orthodontic indices
  • List of orthodontic functional appliances
  • Molar distalization
  • Mouth breathing
  • Obligate nasal breathing

Notes

[edit]
  1. ^ Also referred to as orthodontia
  2. ^ "Orthodontics" comes from the Greek orthos ('correct, straight') and -odont- ('tooth').[1]

References

[edit]
  1. ^ "Definition of orthodontics | Dictionary.com". www.dictionary.com. Retrieved 2019-08-28.
  2. ^ "What is orthodontics?// Useful Resources: FAQ and Downloadable eBooks". Orthodontics Australia. Retrieved 2020-08-13.
  3. ^ Lombardo G, Vena F, Negri P, Pagano S, Barilotti C, Paglia L, Colombo S, Orso M, Cianetti S (June 2020). "Worldwide prevalence of malocclusion in the different stages of dentition: A systematic review and meta-analysis". Eur J Paediatr Dent. 21 (2): 115–22. doi:10.23804/ejpd.2020.21.02.05. PMID 32567942.
  4. ^ Whitcomb I (2020-07-20). "Evidence and Orthodontics: Does Your Child Really Need Braces?". Undark Magazine. Retrieved 2020-07-27.
  5. ^ "Controversial report finds no proof that dental braces work". British Dental Journal. 226 (2): 91. 2019-01-01. doi:10.1038/sj.bdj.2019.65. ISSN 1476-5373. S2CID 59222957.
  6. ^ von Cramon-Taubadel N (December 2011). "Global human mandibular variation reflects differences in agricultural and hunter-gatherer subsistence strategies". Proceedings of the National Academy of Sciences of the United States of America. 108 (49): 19546–19551. Bibcode:2011PNAS..10819546V. doi:10.1073/pnas.1113050108. PMC 3241821. PMID 22106280.
  7. ^ Rose, Jerome C.; Roblee, Richard D. (June 2009). "Origins of dental crowding and malocclusions: an anthropological perspective". Compendium of Continuing Education in Dentistry (Jamesburg, N.J.: 1995). 30 (5): 292–300. ISSN 1548-8578. PMID 19514263.
  8. ^ a b c d e f g h i j k Proffit WR, Fields Jr HW, Larson BE, Sarver DM (2019). Contemporary orthodontics (Sixth ed.). Philadelphia, PA. ISBN 978-0-323-54387-3. OCLC 1089435881.cite book: CS1 maint: location missing publisher (link)
  9. ^ a b c d e "A Brief History of Orthodontic Braces – ArchWired". www.archwired.com. 17 July 2019.[self-published source]
  10. ^ Peck S (November 2009). "A biographical portrait of Edward Hartley Angle, the first specialist in orthodontics, part 1". The Angle Orthodontist. 79 (6): 1021–1027. doi:10.2319/021009-93.1. PMID 19852589.
  11. ^ "The Application of the Principles of the Edge- wise Arch in the Treatment of Malocclusions: II.*". meridian.allenpress.com. Retrieved 2023-02-07.
  12. ^ "British Orthodontic Society > Museum and Archive > Collection > Fixed Appliances > Begg". www.bos.org.uk. Retrieved 2023-02-07.
  13. ^ Safirstein D (August 2015). "P. Raymond Begg". American Journal of Orthodontics and Dentofacial Orthopedics. 148 (2): 206. doi:10.1016/j.ajodo.2015.06.005. PMID 26232825.
  14. ^ Higley LB (August 1940). "Lateral head roentgenograms and their relation to the orthodontic problem". American Journal of Orthodontics and Oral Surgery. 26 (8): 768–778. doi:10.1016/S0096-6347(40)90331-3. ISSN 0096-6347.
  15. ^ Themes UF (2015-01-12). "14: Cephalometric radiography". Pocket Dentistry. Retrieved 2023-02-07.
  16. ^ a b Andrews LF (December 2015). "The 6-elements orthodontic philosophy: Treatment goals, classification, and rules for treating". American Journal of Orthodontics and Dentofacial Orthopedics. 148 (6): 883–887. doi:10.1016/j.ajodo.2015.09.011. PMID 26672688.
  17. ^ Andrews LF (September 1972). "The six keys to normal occlusion". American Journal of Orthodontics. 62 (3): 296–309. doi:10.1016/s0002-9416(72)90268-0. PMID 4505873. S2CID 8039883.
  18. ^ a b Themes UF (2015-01-01). "31 The straight wire appliance". Pocket Dentistry. Retrieved 2023-02-07.
  19. ^ Andrews LF (July 1979). "The straight-wire appliance". British Journal of Orthodontics. 6 (3): 125–143. doi:10.1179/bjo.6.3.125. PMID 297458. S2CID 33259729.
  20. ^ Phulari B (2013), "Andrews' Straight Wire Appliance", History of Orthodontics, Jaypee Brothers Medical Publishers (P) Ltd., p. 98, doi:10.5005/jp/books/12065_11, ISBN 9789350904718, retrieved 2023-02-07
  21. ^ Angle EH. Treatment of malocclusion of the teeth. 7th éd. Philadelphia: S.S.White Dental Mfg Cy, 1907
  22. ^ Philippe J (March 2008). "How, why, and when was the edgewise appliance born?". Journal of Dentofacial Anomalies and Orthodontics. 11 (1): 68–74. doi:10.1051/odfen/20084210113. ISSN 2110-5715.
  23. ^ Angle EH (1912). "Evolution of orthodontia. Recent developments". Dental Cosmos. 54: 853–867.
  24. ^ Brodie AG (1931). "A discussion on the Newest Angle Mechanism". The Angle Orthodontist. 1: 32–38.
  25. ^ Angle EH (1928). "The latest and best in Orthodontic Mechanism". Dental Cosmos. 70: 1143–1156.
  26. ^ Brodie AG (1956). "Orthodontic Concepts Prior to the Death of Edward Angle". The Angle Orthodontist. 26: 144–155.
  27. ^ Matasa CG, Graber TM (April 2000). "Angle, the innovator, mechanical genius, and clinician". American Journal of Orthodontics and Dentofacial Orthopedics. 117 (4): 444–452. doi:10.1016/S0889-5406(00)70164-8. PMID 10756270.
  28. ^ Andrews LF. Straight Wire: The Concept and Appliance. San Diego: LA Wells; 1989.
  29. ^ Andrews LF (1989). Straight wire: the concept and appliance. Lisa Schirmer. San Diego, CA. ISBN 978-0-9616256-0-3. OCLC 22808470.cite book: CS1 maint: location missing publisher (link)
  30. ^ Roth RH (November 1976). "Five year clinical evaluation of the Andrews straight-wire appliance". Journal of Clinical Orthodontics. 10 (11): 836–50. PMID 1069735.
  31. ^ Fleming PS, Fedorowicz Z, Johal A, El-Angbawi A, Pandis N, et al. (The Cochrane Collaboration) (June 2015). "Surgical adjunctive procedures for accelerating orthodontic treatment". The Cochrane Database of Systematic Reviews. 2015 (6). John Wiley & Sons, Ltd.: CD010572. doi:10.1002/14651858.cd010572. PMC 6464946. PMID 26123284.
  32. ^ "What is an Orthodontist?". Orthodontics Australia. 5 December 2019.
  33. ^ Dardengo C, Fernandes LQ, Capelli Júnior J (February 2016). "Frequency of orthodontic extraction". Dental Press Journal of Orthodontics. 21 (1): 54–59. doi:10.1590/2177-6709.21.1.054-059.oar. PMC 4816586. PMID 27007762.
  34. ^ "Child Dental Health Survey 2013, England, Wales and Northern Ireland". digital.nhs.uk. Retrieved 2018-03-08.
  35. ^ Atsawasuwan P, Shirazi S (2019-04-10). "Advances in Orthodontic Tooth Movement: Gene Therapy and Molecular Biology Aspect". In Aslan BI, Uzuner FD (eds.). Current Approaches in Orthodontics. IntechOpen. doi:10.5772/intechopen.80287. ISBN 978-1-78985-181-6. Retrieved 2021-05-16.
  36. ^ a b "Elastics For Braces: Rubber Bands in Orthodontics". Orthodontics Australia. 2019-12-15. Retrieved 2020-12-13.
  37. ^ Mitchell L (2013). An Introduction to Orthodontics. Oxford Medical Publications. pp. 220–233.
  38. ^ Rossini G, Parrini S, Castroflorio T, Deregibus A, Debernardi CL (September 2015). "Efficacy of clear aligners in controlling orthodontic tooth movement: a systematic review". The Angle Orthodontist. 85 (5): 881–889. doi:10.2319/061614-436.1. PMC 8610387. PMID 25412265. S2CID 10787375. The quality level of the studies was not sufficient to draw any evidence-based conclusions.
  39. ^ "Dental Braces and Retainers".
  40. ^ Millett DT, Cunningham SJ, O'Brien KD, Benson PE, de Oliveira CM (February 2018). "Orthodontic treatment for deep bite and retroclined upper front teeth in children". The Cochrane Database of Systematic Reviews. 2 (2): CD005972. doi:10.1002/14651858.CD005972.pub4. PMC 6491166. PMID 29390172.
  41. ^ "Palate Expander". Cleveland Clinic. Retrieved October 29, 2024.
  42. ^ "Jaw Surgery". Modern Orthodontic Clinic in Sammamish & Bellevue. Retrieved 2024-10-03.
  43. ^ Agnihotry A, Fedorowicz Z, Nasser M, Gill KS, et al. (The Cochrane Collaboration) (October 2017). Zbigniew F (ed.). "Resorbable versus titanium plates for orthognathic surgery". The Cochrane Database of Systematic Reviews. 10 (10). John Wiley & Sons, Ltd: CD006204. doi:10.1002/14651858.cd006204. PMC 6485457. PMID 28977689.
  44. ^ "British Orthodontic Society > Public & Patients > Your Jaw Surgery". www.bos.org.uk. Retrieved 2019-08-28.
  45. ^ Fleming PS, Strydom H, Katsaros C, MacDonald L, Curatolo M, Fudalej P, Pandis N, et al. (Cochrane Oral Health Group) (December 2016). "Non-pharmacological interventions for alleviating pain during orthodontic treatment". The Cochrane Database of Systematic Reviews. 2016 (12): CD010263. doi:10.1002/14651858.CD010263.pub2. PMC 6463902. PMID 28009052.
  46. ^ Yu Y, Sun J, Lai W, Wu T, Koshy S, Shi Z (September 2013). "Interventions for managing relapse of the lower front teeth after orthodontic treatment". The Cochrane Database of Systematic Reviews. 2014 (9): CD008734. doi:10.1002/14651858.CD008734.pub2. PMC 10793711. PMID 24014170.
  47. ^ "Clear Retainers | Maintain Your Hard to Get Smile with Clear Retainers". Retrieved 2020-01-13.
  48. ^ a b Martin C, Littlewood SJ, Millett DT, Doubleday B, Bearn D, Worthington HV, Limones A (May 2023). "Retention procedures for stabilising tooth position after treatment with orthodontic braces". The Cochrane Database of Systematic Reviews. 2023 (5): CD002283. doi:10.1002/14651858.CD002283.pub5. PMC 10202160. PMID 37219527.
  49. ^ Putrino A, Barbato E, Galluccio G (March 2021). "Clear Aligners: Between Evolution and Efficiency-A Scoping Review". International Journal of Environmental Research and Public Health. 18 (6): 2870. doi:10.3390/ijerph18062870. PMC 7998651. PMID 33799682.
  50. ^ a b Christensen GJ (March 2002). "Orthodontics and the general practitioner". Journal of the American Dental Association. 133 (3): 369–371. doi:10.14219/jada.archive.2002.0178. PMID 11934193.
  51. ^ "How to become an orthodontist". Orthodontics Australia. 26 September 2017.
  52. ^ "Studying orthodontics". Australian Society of Orthodontists. 26 September 2017.
  53. ^ "Specialties and Specialty Fields". Australian Health Practitioners Regulation Agency.
  54. ^ "Medical Specialties and Specialty Fields". Medical Board of Australia.
  55. ^ a b c "Dhaka Dental College". Dhaka Dental College. Archived from the original on October 28, 2017. Retrieved October 28, 2017.
  56. ^ "List of recognized medical and dental colleges". Bangladesh Medical & Dental Council (BM&DC). Retrieved October 28, 2017.
  57. ^ "Orthodontic Facts - Canadian Association of Orthodontists". Canadian Association of Orthodontists. Retrieved 26 October 2017.
  58. ^ a b c "FAQ: I Want To Be An Orthodontist - Canadian Association of Orthodontists". Canadian Association of Orthodontists. Retrieved 26 October 2017.
  59. ^ "RCDC - Eligibility". The Royal College of Dentists of Canada. Archived from the original on 29 October 2019. Retrieved 26 October 2017.
  60. ^ "Accredited Orthodontic Programs - AAO Members". www.aaoinfo.org.
  61. ^ a b c d e f "About Board Certification". American Board of Orthodontists. Archived from the original on 16 February 2019. Retrieved 26 October 2017.
  62. ^ "Accredited Orthodontic Programs | AAO Members". American Association of Orthodontists. Retrieved 26 October 2017.
  63. ^ a b c d e f "Orthodontic Specialty Training in the UK" (PDF). British Orthodontic Society. Retrieved 28 October 2017.

 

 

International children in traditional clothing at Liberty Weekend

A child (pl.children) is a human being between the stages of birth and puberty,[1][2] or between the developmental period of infancy and puberty.[3] The term may also refer to an unborn human being.[4][5] In English-speaking countries, the legal definition of child generally refers to a minor, in this case as a person younger than the local age of majority (there are exceptions like, for example, the consume and purchase of alcoholic beverage even after said age of majority[6]), regardless of their physical, mental and sexual development as biological adults.[1][7][8] Children generally have fewer rights and responsibilities than adults. They are generally classed as unable to make serious decisions.

Child may also describe a relationship with a parent (such as sons and daughters of any age)[9] or, metaphorically, an authority figure, or signify group membership in a clan, tribe, or religion; it can also signify being strongly affected by a specific time, place, or circumstance, as in "a child of nature" or "a child of the Sixties."[10]

[edit]
Children playing ball games, Roman artwork, 2nd century AD

In the biological sciences, a child is usually defined as a person between birth and puberty,[1][2] or between the developmental period of infancy and puberty.[3] Legally, the term child may refer to anyone below the age of majority or some other age limit.

The United Nations Convention on the Rights of the Child defines child as, "A human being below the age of 18 years unless under the law applicable to the child, majority is attained earlier."[11] This is ratified by 192 of 194 member countries. The term child may also refer to someone below another legally defined age limit unconnected to the age of majority. In Singapore, for example, a child is legally defined as someone under the age of 14 under the "Children and Young Persons Act" whereas the age of majority is 21.[12][13] In U.S. Immigration Law, a child refers to anyone who is under the age of 21.[14]

Some English definitions of the word child include the fetus (sometimes termed the unborn).[15] In many cultures, a child is considered an adult after undergoing a rite of passage, which may or may not correspond to the time of puberty.

Children generally have fewer rights than adults and are classed as unable to make serious decisions, and legally must always be under the care of a responsible adult or child custody, whether their parents divorce or not.

Developmental stages of childhood

[edit]

Early childhood

[edit]
Children playing the violin in a group recital, Ithaca, New York, 2011
Children in Madagascar, 2011
Child playing piano, 1984

Early childhood follows the infancy stage and begins with toddlerhood when the child begins speaking or taking steps independently.[16][17] While toddlerhood ends around age 3 when the child becomes less dependent on parental assistance for basic needs, early childhood continues approximately until the age of 5 or 6. However, according to the National Association for the Education of Young Children, early childhood also includes infancy. At this stage children are learning through observing, experimenting and communicating with others. Adults supervise and support the development process of the child, which then will lead to the child's autonomy. Also during this stage, a strong emotional bond is created between the child and the care providers. The children also start preschool and kindergarten at this age: and hence their social lives.

Middle childhood

[edit]

Middle childhood begins at around age 7, and ends at around age 9 or 10.[18] Together, early and middle childhood are called formative years. In this middle period, children develop socially and mentally. They are at a stage where they make new friends and gain new skills, which will enable them to become more independent and enhance their individuality. During middle childhood, children enter the school years, where they are presented with a different setting than they are used to. This new setting creates new challenges and faces for children.[19] Upon the entrance of school, mental disorders that would normally not be noticed come to light. Many of these disorders include: autism, dyslexia, dyscalculia, and ADHD.[20]: 303–309  Special education, least restrictive environment, response to intervention and individualized education plans are all specialized plans to help children with disabilities.[20]: 310–311 

Middle childhood is the time when children begin to understand responsibility and are beginning to be shaped by their peers and parents. Chores and more responsible decisions come at this time, as do social comparison and social play.[20]: 338  During social play, children learn from and teach each other, often through observation.[21]

Late childhood

[edit]

Preadolescence is a stage of human development following early childhood and preceding adolescence. Preadolescence is commonly defined as ages 9–12, ending with the major onset of puberty, with markers such as menarche, spermarche, and the peak of height velocity occurring. These changes usually occur between ages 11 and 14. It may also be defined as the 2-year period before the major onset of puberty.[22] Preadolescence can bring its own challenges and anxieties. Preadolescent children have a different view of the world from younger children in many significant ways. Typically, theirs is a more realistic view of life than the intense, fantasy-oriented world of earliest childhood. Preadolescents have more mature, sensible, realistic thoughts and actions: 'the most "sensible" stage of development...the child is a much less emotional being now.'[23] Preadolescents may well view human relationships differently (e.g. they may notice the flawed, human side of authority figures). Alongside that, they may begin to develop a sense of self-identity, and to have increased feelings of independence: 'may feel an individual, no longer "just one of the family."'[24]

Developmental stages post-childhood

[edit]

Adolescence

[edit]
An adolescent girl, photographed by Paolo Monti

Adolescence is usually determined to be between the onset of puberty and legal adulthood: mostly corresponding to the teenage years (13–19). However, puberty usually begins before the teenage years (10—11 for girls and 11—12 for boys). Although biologically a child is a human being between the stages of birth and puberty,[1][2] adolescents are legally considered children, as they tend to lack adult rights and are still required to attend compulsory schooling in many cultures, though this varies. The onset of adolescence brings about various physical, psychological and behavioral changes. The end of adolescence and the beginning of adulthood varies by country and by function, and even within a single nation-state or culture there may be different ages at which an individual is considered to be mature enough to be entrusted by society with certain tasks.

History

[edit]
Playing Children, by Song dynasty Chinese artist Su Hanchen, c. 1150 AD.

During the European Renaissance, artistic depictions of children increased dramatically, which did not have much effect on the social attitude toward children, however.[25]

The French historian Philippe Ariès argued that during the 1600s, the concept of childhood began to emerge in Europe,[26] however other historians like Nicholas Orme have challenged this view and argued that childhood has been seen as a separate stage since at least the medieval period.[27] Adults saw children as separate beings, innocent and in need of protection and training by the adults around them. The English philosopher John Locke was particularly influential in defining this new attitude towards children, especially with regard to his theory of the tabula rasa, which considered the mind at birth to be a "blank slate". A corollary of this doctrine was that the mind of the child was born blank, and that it was the duty of the parents to imbue the child with correct notions. During the early period of capitalism, the rise of a large, commercial middle class, mainly in the Protestant countries of the Dutch Republic and England, brought about a new family ideology centred around the upbringing of children. Puritanism stressed the importance of individual salvation and concern for the spiritual welfare of children.[28]

The Age of Innocence c. 1785/8. Reynolds emphasized the natural grace of children in his paintings.

The modern notion of childhood with its own autonomy and goals began to emerge during the 18th-century Enlightenment and the Romantic period that followed it.[29][30] Jean Jacques Rousseau formulated the romantic attitude towards children in his famous 1762 novel Emile: or, On Education. Building on the ideas of John Locke and other 17th-century thinkers, Jean-Jaques Rousseau described childhood as a brief period of sanctuary before people encounter the perils and hardships of adulthood.[29] Sir Joshua Reynolds' extensive children portraiture demonstrated the new enlightened attitudes toward young children. His 1788 painting The Age of Innocence emphasizes the innocence and natural grace of the posing child and soon became a public favourite.[31]

Brazilian princesses Leopoldina (left) and Isabel (center) with an unidentified friend, c. 1860.

The idea of childhood as a locus of divinity, purity, and innocence is further expounded upon in William Wordsworth's "Ode: Intimations of Immortality from Recollections of Early Childhood", the imagery of which he "fashioned from a complex mix of pastoral aesthetics, pantheistic views of divinity, and an idea of spiritual purity based on an Edenic notion of pastoral innocence infused with Neoplatonic notions of reincarnation".[30] This Romantic conception of childhood, historian Margaret Reeves suggests, has a longer history than generally recognized, with its roots traceable to similarly imaginative constructions of childhood circulating, for example, in the neo-platonic poetry of seventeenth-century metaphysical poet Henry Vaughan (e.g., "The Retreate", 1650; "Childe-hood", 1655). Such views contrasted with the stridently didactic, Calvinist views of infant depravity.[32]

Armenian scouts in 1918

With the onset of industrialisation in England in 1760, the divergence between high-minded romantic ideals of childhood and the reality of the growing magnitude of child exploitation in the workplace, became increasingly apparent. By the late 18th century, British children were specially employed in factories and mines and as chimney sweeps,[33] often working long hours in dangerous jobs for low pay.[34] As the century wore on, the contradiction between the conditions on the ground for poor children and the middle-class notion of childhood as a time of simplicity and innocence led to the first campaigns for the imposition of legal protection for children.

British reformers attacked child labor from the 1830s onward, bolstered by the horrific descriptions of London street life by Charles Dickens.[35] The campaign eventually led to the Factory Acts, which mitigated the exploitation of children at the workplace[33][36]

Modern concepts of childhood

[edit]
Children play in a fountain in a summer evening, Davis, California.
An old man and his granddaughter in Turkey.
Nepalese children playing with cats.
Harari girls in Ethiopia.

The modern attitude to children emerged by the late 19th century; the Victorian middle and upper classes emphasized the role of the family and the sanctity of the child – an attitude that has remained dominant in Western societies ever since.[37] The genre of children's literature took off, with a proliferation of humorous, child-oriented books attuned to the child's imagination. Lewis Carroll's fantasy Alice's Adventures in Wonderland, published in 1865 in England, was a landmark in the genre; regarded as the first "English masterpiece written for children", its publication opened the "First Golden Age" of children's literature.

The latter half of the 19th century saw the introduction of compulsory state schooling of children across Europe, which decisively removed children from the workplace into schools.[38][39]

The market economy of the 19th century enabled the concept of childhood as a time of fun, happiness, and imagination. Factory-made dolls and doll houses delighted the girls and organized sports and activities were played by the boys.[40] The Boy Scouts was founded by Sir Robert Baden-Powell in 1908,[41][42] which provided young boys with outdoor activities aiming at developing character, citizenship, and personal fitness qualities.[43]

In the 20th century, Philippe Ariès, a French historian specializing in medieval history, suggested that childhood was not a natural phenomenon, but a creation of society in his 1960 book Centuries of Childhood. In 1961 he published a study of paintings, gravestones, furniture, and school records, finding that before the 17th century, children were represented as mini-adults.

In 1966, the American philosopher George Boas published the book The Cult of Childhood. Since then, historians have increasingly researched childhood in past times.[44]

In 2006, Hugh Cunningham published the book Invention of Childhood, looking at British childhood from the year 1000, the Middle Ages, to what he refers to as the Post War Period of the 1950s, 1960s and 1970s.[45]

Childhood evolves and changes as lifestyles change and adult expectations alter. In the modern era, many adults believe that children should not have any worries or work, as life should be happy and trouble-free. Childhood is seen as a mixture of simplicity, innocence, happiness, fun, imagination, and wonder. It is thought of as a time of playing, learning, socializing, exploring, and worrying in a world without much adult interference.[29][30]

A "loss of innocence" is a common concept, and is often seen as an integral part of coming of age. It is usually thought of as an experience or period in a child's life that widens their awareness of evil, pain or the world around them. This theme is demonstrated in the novels To Kill a Mockingbird and Lord of the Flies. The fictional character Peter Pan was the embodiment of a childhood that never ends.[46][47]

Healthy childhoods

[edit]

Role of parents

[edit]

Children's health

[edit]

Children's health includes the physical, mental and social well-being of children. Maintaining children's health implies offering them healthy foods, insuring they get enough sleep and exercise, and protecting their safety.[48] Children in certain parts of the world often suffer from malnutrition, which is often associated with other conditions, such diarrhea, pneumonia and malaria.[49]

Child protection

[edit]

Child protection, according to UNICEF, refers to "preventing and responding to violence, exploitation and abuse against children – including commercial sexual exploitation, trafficking, child labour and harmful traditional practices, such as female genital mutilation/cutting and child marriage".[50] The Convention on the Rights of the Child protects the fundamental rights of children.

Play

[edit]
Dancing at Mother of Peace AIDs orphanage, Zimbabwe

Play is essential to the cognitive, physical, social, and emotional well-being of children.[51] It offers children opportunities for physical (running, jumping, climbing, etc.), intellectual (social skills, community norms, ethics and general knowledge) and emotional development (empathy, compassion, and friendships). Unstructured play encourages creativity and imagination. Playing and interacting with other children, as well as some adults, provides opportunities for friendships, social interactions, conflicts and resolutions. However, adults tend to (often mistakenly) assume that virtually all children's social activities can be understood as "play" and, furthermore, that children's play activities do not involve much skill or effort.[52][53][54][55]

It is through play that children at a very early age engage and interact in the world around them. Play allows children to create and explore a world they can master, conquering their fears while practicing adult roles, sometimes in conjunction with other children or adult caregivers.[51] Undirected play allows children to learn how to work in groups, to share, to negotiate, to resolve conflicts, and to learn self-advocacy skills. However, when play is controlled by adults, children acquiesce to adult rules and concerns and lose some of the benefits play offers them. This is especially true in developing creativity, leadership, and group skills.[51]

Ralph Hedley, The Tournament, 1898. It depicts poorer boys playing outdoors in a rural part of the Northeast of England.

Play is considered to be very important to optimal child development that it has been recognized by the United Nations Commission on Human Rights as a right of every child.[11] Children who are being raised in a hurried and pressured style may limit the protective benefits they would gain from child-driven play.[51]

The initiation of play in a classroom setting allows teachers and students to interact through playfulness associated with a learning experience. Therefore, playfulness aids the interactions between adults and children in a learning environment. “Playful Structure” means to combine informal learning with formal learning to produce an effective learning experience for children at a young age.[56]

Even though play is considered to be the most important to optimal child development, the environment affects their play and therefore their development. Poor children confront widespread environmental inequities as they experience less social support, and their parents are less responsive and more authoritarian. Children from low income families are less likely to have access to books and computers which would enhance their development.[57]

Street culture

[edit]
Children in front of a movie theatre, Toronto, 1920s.

Children's street culture refers to the cumulative culture created by young children and is sometimes referred to as their secret world. It is most common in children between the ages of seven and twelve. It is strongest in urban working class industrial districts where children are traditionally free to play out in the streets for long periods without supervision. It is invented and largely sustained by children themselves with little adult interference.

Young children's street culture usually takes place on quiet backstreets and pavements, and along routes that venture out into local parks, playgrounds, scrub and wasteland, and to local shops. It often imposes imaginative status on certain sections of the urban realm (local buildings, kerbs, street objects, etc.). Children designate specific areas that serve as informal meeting and relaxation places (see: Sobel, 2001). An urban area that looks faceless or neglected to an adult may have deep 'spirit of place' meanings in to children. Since the advent of indoor distractions such as video games, and television, concerns have been expressed about the vitality – or even the survival – of children's street culture.

Geographies of childhood

[edit]

The geographies of childhood involves how (adult) society perceives the idea of childhood, the many ways adult attitudes and behaviors affect children's lives, including the environment which surrounds children and its implications.[58]

The geographies of childhood is similar in some respects to children's geographies which examines the places and spaces in which children live.[59]

Nature deficit disorder

[edit]

Nature Deficit Disorder, a term coined by Richard Louv in his 2005 book Last Child in the Woods, refers to the trend in the United States and Canada towards less time for outdoor play,[60][61] resulting in a wide range of behavioral problems.[62]

With increasing use of cellphones, computers, video games and television, children have more reasons to stay inside rather than outdoors exploring. “The average American child spends 44 hours a week with electronic media”.[63] Research in 2007 has drawn a correlation between the declining number of National Park visits in the U.S. and increasing consumption of electronic media by children.[64] The media has accelerated the trend for children's nature disconnection by deemphasizing views of nature, as in Disney films.[65]

Age of responsibility

[edit]

The age at which children are considered responsible for their society-bound actions (e. g. marriage, voting, etc.) has also changed over time,[66] and this is reflected in the way they are treated in courts of law. In Roman times, children were regarded as not culpable for crimes, a position later adopted by the Church. In the 19th century, children younger than seven years old were believed incapable of crime. Children from the age of seven forward were considered responsible for their actions. Therefore, they could face criminal charges, be sent to adult prison, and be punished like adults by whipping, branding or hanging. However, courts at the time would consider the offender's age when deliberating sentencing.[citation needed] Minimum employment age and marriage age also vary. The age limit of voluntary/involuntary military service is also disputed at the international level.[67]

Education

[edit]
Children in an outdoor classroom in Bié, Angola
Children seated in a Finnish classroom at the school of Torvinen in Sodankylä, Finland, in the 1920s

Education, in the general sense, refers to the act or process of imparting or acquiring general knowledge, developing the powers of reasoning and judgment, and preparing intellectually for mature life.[68] Formal education most often takes place through schooling. A right to education has been recognized by some governments. At the global level, Article 13 of the United Nations' 1966 International Covenant on Economic, Social and Cultural Rights (ICESCR) recognizes the right of everyone to an education.[69] Education is compulsory in most places up to a certain age, but attendance at school may not be, with alternative options such as home-schooling or e-learning being recognized as valid forms of education in certain jurisdictions.

Children in some countries (especially in parts of Africa and Asia) are often kept out of school, or attend only for short periods. Data from UNICEF indicate that in 2011, 57 million children were out of school; and more than 20% of African children have never attended primary school or have left without completing primary education.[70] According to a UN report, warfare is preventing 28 million children worldwide from receiving an education, due to the risk of sexual violence and attacks in schools.[71] Other factors that keep children out of school include poverty, child labor, social attitudes, and long distances to school.[72][73]

Attitudes toward children

[edit]
Group of breaker boys in Pittston, Pennsylvania, 1911. Child labor was widespread until the early 20th century. In the 21st century, child labor rates are highest in Africa.

Social attitudes toward children differ around the world in various cultures and change over time. A 1988 study on European attitudes toward the centrality of children found that Italy was more child-centric and the Netherlands less child-centric, with other countries, such as Austria, Great Britain, Ireland and West Germany falling in between.[74]

Child marriage

[edit]

In 2013, child marriage rates of female children under the age of 18 reached 75% in Niger, 68% in Central African Republic and Chad, 66% in Bangladesh, and 47% in India.[75] According to a 2019 UNICEF report on child marriage, 37% of females were married before the age of 18 in sub-Saharan Africa, followed by South Asia at 30%. Lower levels were found in Latin America and Caribbean (25%), the Middle East and North Africa (18%), and Eastern Europe and Central Asia (11%), while rates in Western Europe and North America were minimal.[76] Child marriage is more prevalent with girls, but also involves boys. A 2018 study in the journal Vulnerable Children and Youth Studies found that, worldwide, 4.5% of males are married before age 18, with the Central African Republic having the highest average rate at 27.9%.[77]

Fertility and number of children per woman

[edit]

Before contraception became widely available in the 20th century, women had little choice other than abstinence or having often many children. In fact, current population growth concerns have only become possible with drastically reduced child mortality and sustained fertility. In 2017 the global total fertility rate was estimated to be 2.37 children per woman,[78] adding about 80 million people to the world population per year. In order to measure the total number of children, scientists often prefer the completed cohort fertility at age 50 years (CCF50).[78] Although the number of children is also influenced by cultural norms, religion, peer pressure and other social factors, the CCF50 appears to be most heavily dependent on the educational level of women, ranging from 5–8 children in women without education to less than 2 in women with 12 or more years of education.[78]

Issues

[edit]

Emergencies and conflicts

[edit]

Emergencies and conflicts pose detrimental risks to the health, safety, and well-being of children. There are many different kinds of conflicts and emergencies, e.g. wars and natural disasters. As of 2010 approximately 13 million children are displaced by armed conflicts and violence around the world.[79] Where violent conflicts are the norm, the lives of young children are significantly disrupted and their families have great difficulty in offering the sensitive and consistent care that young children need for their healthy development.[79] Studies on the effect of emergencies and conflict on the physical and mental health of children between birth and 8 years old show that where the disaster is natural, the rate of PTSD occurs in anywhere from 3 to 87 percent of affected children.[80] However, rates of PTSD for children living in chronic conflict conditions varies from 15 to 50 percent.[81][82]

Child protection

[edit]
 

Child protection (also called child welfare) is the safeguarding of children from violence, exploitation, abuse, abandonment, and neglect.[83][84][85][86] It involves identifying signs of potential harm. This includes responding to allegations or suspicions of abuse, providing support and services to protect children, and holding those who have harmed them accountable.[87]

The primary goal of child protection is to ensure that all children are safe and free from harm or danger.[86][88] Child protection also works to prevent future harm by creating policies and systems that identify and respond to risks before they lead to harm.[89]

In order to achieve these goals, research suggests that child protection services should be provided in a holistic way.[90][91][92] This means taking into account the social, economic, cultural, psychological, and environmental factors that can contribute to the risk of harm for individual children and their families. Collaboration across sectors and disciplines to create a comprehensive system of support and safety for children is required.[93][94]

It is the responsibility of individuals, organizations, and governments to ensure that children are protected from harm and their rights are respected.[95] This includes providing a safe environment for children to grow and develop, protecting them from physical, emotional and sexual abuse, and ensuring they have access to education, healthcare, and resources to fulfill their basic needs.[96]

Child protection systems are a set of services, usually government-run, designed to protect children and young people who are underage and to encourage family stability. UNICEF defines[97] a 'child protection system' as:

"The set of laws, policies, regulations and services needed across all social sectors – especially social welfare, education, health, security and justice – to support prevention and response to protection-related risks. These systems are part of social protection, and extend beyond it. At the level of prevention, their aim includes supporting and strengthening families to reduce social exclusion, and to lower the risk of separation, violence and exploitation. Responsibilities are often spread across government agencies, with services delivered by local authorities, non-State providers, and community groups, making coordination between sectors and levels, including routine referral systems etc.., a necessary component of effective child protection systems."

— United Nations Economic and Social Council (2008), UNICEF Child Protection Strategy, E/ICEF/2008/5/Rev.1, par. 12–13.

Under Article 19 of the UN Convention on the Rights of the Child, a 'child protection system' provides for the protection of children in and out of the home. One of the ways this can be enabled is through the provision of quality education, the fourth of the United Nations Sustainable Development Goals, in addition to other child protection systems. Some literature argues that child protection begins at conception; even how the conception took place can affect the child's development.[98]

Child abuse and child labor

[edit]

Protection of children from abuse is considered an important contemporary goal. This includes protecting children from exploitation such as child labor, child trafficking and child selling, child sexual abuse, including child prostitution and child pornography, military use of children, and child laundering in illegal adoptions. There exist several international instruments for these purposes, such as:

  • Worst Forms of Child Labour Convention
  • Minimum Age Convention, 1973
  • Optional Protocol on the Sale of Children, Child Prostitution and Child Pornography
  • Council of Europe Convention on the Protection of Children against Sexual Exploitation and Sexual Abuse
  • Optional Protocol on the Involvement of Children in Armed Conflict
  • Hague Adoption Convention

Climate change

[edit]
 
A child at a climate demonstration in Juneau, Alaska

Children are more vulnerable to the effects of climate change than adults. The World Health Organization estimated that 88% of the existing global burden of disease caused by climate change affects children under five years of age.[99] A Lancet review on health and climate change lists children as the worst-affected category by climate change.[100] Children under 14 are 44 percent more likely to die from environmental factors,[101] and those in urban areas are disproportionately impacted by lower air quality and overcrowding.[102]

Children are physically more vulnerable to climate change in all its forms.[103] Climate change affects the physical health of children and their well-being. Prevailing inequalities, between and within countries, determine how climate change impacts children.[104] Children often have no voice in terms of global responses to climate change.[103]

People living in low-income countries experience a higher burden of disease and are less capable of coping with climate change-related threats.[105] Nearly every child in the world is at risk from climate change and pollution, while almost half are at extreme risk.[106]

Health

[edit]

Child mortality

[edit]
World infant mortality rates in 2012.[107]

During the early 17th century in England, about two-thirds of all children died before the age of four.[108] During the Industrial Revolution, the life expectancy of children increased dramatically.[109] This has continued in England, and in the 21st century child mortality rates have fallen across the world. About 12.6 million under-five infants died worldwide in 1990, which declined to 6.6 million in 2012. The infant mortality rate dropped from 90 deaths per 1,000 live births in 1990, to 48 in 2012. The highest average infant mortality rates are in sub-Saharan Africa, at 98 deaths per 1,000 live births – over double the world's average.[107]

See also

[edit]
Listen to this article (3 minutes)
 
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This audio file was created from a revision of this article dated 24 June 2008 (2008-06-24), and does not reflect subsequent edits.
  • Outline of childhood
  • Child slavery
  • Childlessness
  • Depression in childhood and adolescence
  • One-child policy
  • Religion and children
  • Youth rights
  • Archaeology of childhood

Sources

[edit]
  •  This article incorporates text from a free content work. Licensed under CC-BY-SA IGO 3.0 (license statement/permission). Text taken from Investing against Evidence: The Global State of Early Childhood Care and Education​, 118–125, Marope PT, Kaga Y, UNESCO. UNESCO.
  •  This article incorporates text from a free content work. Licensed under CC-BY-SA IGO 3.0 (license statement/permission). Text taken from Creating sustainable futures for all; Global education monitoring report, 2016; Gender review​, 20, UNESCO, UNESCO. UNESCO.

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  84. ^ Oates, Kim (July 2013). "Medical dimensions of child abuse and neglect". Child Abuse & Neglect. 37 (7): 427–429. doi:10.1016/j.chiabu.2013.05.004. ISSN 0145-2134. PMID 23790510.
  85. ^ Southall, David; MacDonald, Rhona (1 November 2013). "Protecting children from abuse: a neglected but crucial priority for the international child health agenda". Paediatrics and International Child Health. 33 (4): 199–206. doi:10.1179/2046905513Y.0000000097. ISSN 2046-9047. PMID 24070186. S2CID 29250788.
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  87. ^ Child Custody & Domestic Violence: A Call for Safety and Accountability. Thousand Oaks, California: SAGE Publications, Inc. 2003. doi:10.4135/9781452231730. ISBN 978-0-7619-1826-4.
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Further reading

[edit]
  • Cook, Daniel Thomas. The moral project of childhood: Motherhood, material life, and early children's consumer culture (NYU Press, 2020). online book see also online review
  • Fawcett, Barbara, Brid Featherstone, and Jim Goddard. Contemporary child care policy and practice (Bloomsbury Publishing, 2017) online
  • Hutchison, Elizabeth D., and Leanne W. Charlesworth. "Securing the welfare of children: Policies past, present, and future." Families in Society 81.6 (2000): 576–585.
  • Fass, Paula S. The end of American childhood: A history of parenting from life on the frontier to the managed child (Princeton University Press, 2016).
  • Fass, Paula S. ed. The Routledge History of Childhood in the Western World (2012) online
  • Klass, Perri. The Best Medicine: How Science and Public Health Gave Children a Future (WW Norton & Company, 2020) online
  • Michail, Samia. "Understanding school responses to students’ challenging behaviour: A review of literature." Improving schools 14.2 (2011): 156–171. online
  • Sorin, Reesa. Changing images of childhood: Reconceptualising early childhood practice (Faculty of Education, University of Melbourne, 2005) online.
  • Sorin, Reesa. "Childhood through the eyes of the child and parent." Journal of Australian Research in Early Childhood Education 14.1 (2007). online
  • Vissing, Yvonne. "History of Children’s Human Rights in the USA." in Children's Human Rights in the USA: Challenges and Opportunities (Cham: Springer International Publishing, 2023) pp. 181–212.
  • Yuen, Francis K.O. Social work practice with children and families: a family health approach (Routledge, 2014) online.
Preceded by
Toddlerhood
Stages of human development
Childhood
Succeeded by
Preadolescence

 

Human lower jaw viewed from the left

The jaws are a pair of opposable articulated structures at the entrance of the mouth, typically used for grasping and manipulating food. The term jaws is also broadly applied to the whole of the structures constituting the vault of the mouth and serving to open and close it and is part of the body plan of humans and most animals.

Arthropods

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The mandibles of a bull ant

In arthropods, the jaws are chitinous and oppose laterally, and may consist of mandibles or chelicerae. These jaws are often composed of numerous mouthparts. Their function is fundamentally for food acquisition, conveyance to the mouth, and/or initial processing (mastication or chewing). Many mouthparts and associate structures (such as pedipalps) are modified legs.

Vertebrates

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In most vertebrates, the jaws are bony or cartilaginous and oppose vertically, comprising an upper jaw and a lower jaw. The vertebrate jaw is derived from the most anterior two pharyngeal arches supporting the gills, and usually bears numerous teeth.

Jaws of a great white shark

Fish

[edit]
Moray eels have two sets of jaws: the oral jaws that capture prey and the pharyngeal jaws that advance into the mouth and move prey from the oral jaws to the esophagus for swallowing.

The vertebrate jaw probably originally evolved in the Silurian period and appeared in the Placoderm fish which further diversified in the Devonian. The two most anterior pharyngeal arches are thought to have become the jaw itself and the hyoid arch, respectively. The hyoid system suspends the jaw from the braincase of the skull, permitting great mobility of the jaws. While there is no fossil evidence directly to support this theory, it makes sense in light of the numbers of pharyngeal arches that are visible in extant jawed vertebrates (the Gnathostomes), which have seven arches, and primitive jawless vertebrates (the Agnatha), which have nine.

The original selective advantage offered by the jaw may not be related to feeding, but rather to increased respiration efficiency.[1] The jaws were used in the buccal pump (observable in modern fish and amphibians) that pumps water across the gills of fish or air into the lungs in the case of amphibians. Over evolutionary time the more familiar use of jaws (to humans), in feeding, was selected for and became a very important function in vertebrates. Many teleost fish have substantially modified jaws for suction feeding and jaw protrusion, resulting in highly complex jaws with dozens of bones involved.[2]

Amphibians, reptiles, and birds

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The jaw in tetrapods is substantially simplified compared to fish. Most of the upper jaw bones (premaxilla, maxilla, jugal, quadratojugal, and quadrate) have been fused to the braincase, while the lower jaw bones (dentary, splenial, angular, surangular, and articular) have been fused together into a unit called the mandible. The jaw articulates via a hinge joint between the quadrate and articular. The jaws of tetrapods exhibit varying degrees of mobility between jaw bones. Some species have jaw bones completely fused, while others may have joints allowing for mobility of the dentary, quadrate, or maxilla. The snake skull shows the greatest degree of cranial kinesis, which allows the snake to swallow large prey items.

Mammals

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In mammals, the jaws are made up of the mandible (lower jaw) and the maxilla (upper jaw). In the ape, there is a reinforcement to the lower jaw bone called the simian shelf. In the evolution of the mammalian jaw, two of the bones of the jaw structure (the articular bone of the lower jaw, and quadrate) were reduced in size and incorporated into the ear, while many others have been fused together.[3] As a result, mammals show little or no cranial kinesis, and the mandible is attached to the temporal bone by the temporomandibular joints. Temporomandibular joint dysfunction is a common disorder of these joints, characterized by pain, clicking and limitation of mandibular movement.[4] Especially in the therian mammal, the premaxilla that constituted the anterior tip of the upper jaw in reptiles has reduced in size; and most of the mesenchyme at the ancestral upper jaw tip has become a protruded mammalian nose.[5]

Sea urchins

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Sea urchins possess unique jaws which display five-part symmetry, termed the Aristotle's lantern. Each unit of the jaw holds a single, perpetually growing tooth composed of crystalline calcium carbonate.

See also

[edit]
  • Muscles of mastication
  • Otofacial syndrome
  • Predentary
  • Prognathism
  • Rostral bone

References

[edit]
  1. ^ Smith, M.M.; Coates, M.I. (2000). "10. Evolutionary origins of teeth and jaws: developmental models and phylogenetic patterns". In Teaford, Mark F.; Smith, Moya Meredith; Ferguson, Mark W.J. (eds.). Development, function and evolution of teeth. Cambridge: Cambridge University Press. p. 145. ISBN 978-0-521-57011-4.
  2. ^ Anderson, Philip S.L; Westneat, Mark (28 November 2006). "Feeding mechanics and bite force modelling of the skull of Dunkleosteus terrelli, an ancient apex predator". Biology Letters. pp. 77–80. doi:10.1098/rsbl.2006.0569. PMC 2373817. PMID 17443970. cite web: Missing or empty |url= (help)
  3. ^ Allin EF (December 1975). "Evolution of the mammalian middle ear". J. Morphol. 147 (4): 403–37. doi:10.1002/jmor.1051470404. PMID 1202224. S2CID 25886311.
  4. ^ Wright, Edward F. (2010). Manual of temporomandibular disorders (2nd ed.). Ames, Iowa: Wiley-Blackwell. ISBN 978-0-8138-1324-0.
  5. ^ Higashiyama, Hiroki; Koyabu, Daisuke; Hirasawa, Tatsuya; Werneburg, Ingmar; Kuratani, Shigeru; Kurihara, Hiroki (November 2, 2021). "Mammalian face as an evolutionary novelty". PNAS. 118 (44): e2111876118. Bibcode:2021PNAS..11811876H. doi:10.1073/pnas.2111876118. PMC 8673075. PMID 34716275.
[edit]
  • Media related to Jaw bones at Wikimedia Commons
  • Jaw at the U.S. National Library of Medicine Medical Subject Headings (MeSH)