animals fed softer food had significantly narrower and shorter faces and thinner and shorter mandibles than animals fed hard food. a 2016 review found that breastfeeding lowers the incidence of malocclusions developing later on in developing infants. during the transition to agriculture, the shape of the human mandible went through a series of changes. the mandible underwent a complex shape changes not matched by the teeth, leading to incongruity between the dental and mandibular form. these changes in human skulls may have been "driven by the decreasing bite forces required to chew the processed foods eaten once humans switched to growing different types of cereals, milking and herding animals about 10,000 years ago." treatment orthodontic management of the condition includes dental braces, lingual braces, clear aligners or palatal expanders. other treatments include the removal of one or more teeth and the repair of injured teeth. in some cases, surgery may be necessary. treatment malocclusion is often treated with orthodontics, such as tooth extraction, clear aligners, or dental braces, followed by growth modification in children or jaw surgery (orthognathic surgery) in adults. surgical intervention is used only in rare occasions. this may include surgical reshaping to lengthen or shorten the jaw. wires, plates, or screws may be used to secure the jaw bone, in a manner like the surgical stabilization of jaw fractures. very few people have "perfect" alignment of their teeth with most problems being minor that do not require treatment. crowding crowding of the teeth is treated with orthodontics, often with tooth extraction, clear aligners, or dental braces, followed by growth modification in children or jaw surgery (orthognathic surgery) in adults. surgery may be required on rare occasions. this may include surgical reshaping to lengthen or shorten the jaw (orthognathic surgery). wires, plates, or screws may be used to secure the jaw bone, in a manner similar to the surgical stabilization of jaw fractures. very few people have "perfect" alignment of their teeth. however, most problems are very minor and do not require treatment. class i while treatment is not crucial in class i malocclusions, in severe cases of crowding can be an indication for intervention. studies indicate that tooth extraction can have benefits to correcting malocclusion in individuals. further research is needed as reoccurring crowding has been examined in other clinical trials. class ii a few treatment options for class ii malocclusions include: functional appliance which maintains the mandible in a postured position to influence both the orofacial musculature and dentoalveolar development prior to fixed appliance therapy. this is ideally done through pubertal growth in pre-adolescent children and the fixed appliance during permanent dentition . different types of removable appliances include activator, bionatar, medium opening activator, herbst, frankel and twin block appliance with the twin block being the most widely used one. growth modification through headgear to redirect maxillary growth orthodontic camouflage so that jaw discrepancy no longer apparent orthognathic surgery – sagittal split osteotomy mandibular advancement carried out when growth is complete where skeletal discrepancy is severe in anterior-posterior relationship or in vertical direction. fixed appliance is required before, during and after surgery. upper removable appliance – limited role in contemporary treatment of increased overjets. mostly used for very mild class ii, overjet due to incisor proclination, favourable overbite. class ii division 1 low- to moderate- quality evidence suggests that providing early orthodontic treatment for children with prominent upper front teeth (class ii division 1) is more effective for reducing the incidence of incisal trauma than providing one course of orthodontic treatment in adolescence. there do not appear to be any other advantages of providing early treatment when compared to late treatment. low-quality evidence suggests that, compared to no treatment, late treatment in adolescence with functional appliances is effective for reducing the prominence of upper front teeth. class ii division 2 treatment can be undertaken using orthodontic treatments using dental braces. while treatment is carried out, there is no evidence from clinical trials to recommend or discourage any type of orthodontic treatment in children. a 2018 cochrane systematic review anticipated that the evidence base supporting treatment approaches is not likely to improve occlusion due to the low prevalence of the condition and the ethical difficulties in recruiting people to participate in a randomized controlled trials for treating this condition. class iii the british standard institute (bsi) classify class iii incisor relationship as the lower incisor edge lies anterior to the cingulum plateau of the upper incisors, with reduced or reversed over jet. the skeletal facial deformity is characterized by mandibular prognathism, maxillary retrognathism or a combination of the two. this effects 3-8% of uk population with a higher incidence seen in asia. one of the main reasons for correcting class iii malocclusion is aesthetics and function. this can have a psychological impact on the person with malocclusion resulting in speech and mastication problems as well. in mild class iii cases, the patient is quite accepting of the aesthetics and the situation is monitored to observe the progression of skeletal growth. maxillary and mandibular skeletal changes during prepubertal, pubertal and post pubertal stages show that class iii malocclusion is established before the prepubertal stage. one treatment option is the use of growth modification appliances such as the chin cap which has greatly improved the skeletal framework in the initial stages. however, majority of cases are shown to relapse into inherited class iii malocclusion during the pubertal growth stage and when the appliance is removed after treatment. another approach is to carry out orthognathic surgery, such as a bilateral sagittal split osteotomy (bsso) which is indicated by horizontal mandibular excess. this involves surgically cutting through the mandible and moving the fragment forward or backwards for desired function and is supplemented with pre and post surgical orthodontics to ensure correct tooth relationship. although the most common surgery of the mandible, it comes with several complications including: bleeding from inferior alveolar artery, unfavorable splits, condylar resorption, avascular necrosis and worsening of temporomandibular joint. orthodontic camouflage can also be used in patients with mild skeletal discrepancies. this is a less invasive approach that uses orthodontic brackets to correct malocclusion and try to hide the skeletal discrepancy. due to limitations of orthodontics, this option is more viable for patients who are not as concerned about the aesthetics of their facial appearance and are happy to address the malocclusion only, as well as avoiding the risks which come with orthognathic surgery. deep bite the most common corrective treatments available are fixed or removal appliances (such as dental braces), which may or may not require surgical intervention. at this time there is no robust evidence that treatment will be successful. open bite an open bite malocclusion is when the upper teeth don't overlap the lower teeth. when this malocclusion occurs at the front teeth it is known as anterior open bite. an open bite is difficult to treat due to multifactorial causes, with relapse being a major concern. this is particularly so for an anterior open bite. therefore, it is important to carry out a thorough initial assessment in order to obtain a diagnosis to tailor a suitable treatment plan. it is important to take into consideration any habitual risk factors, as this is crucial for a successful outcome without relapse. treatment approach includes behavior changes, appliances and surgery. treatment for adults include a combination of extractions, fixed appliances, intermaxillary elastics and orthognathic surgery. for children, orthodontics is usually used to compensate for continued growth. with children with mixed dentition, the malocclusion may resolve on its own as the permanent teeth erupt. furthermore, should the malocclusion be caused by childhood habits such as digit, thumb or pacifier sucking, it may result in resolution as the habit is stopped. habit deterrent appliances may be used to help in breaking digit and thumb sucking habits. other treatment options for patients who are still growing include functional appliances and headgear appliances. tooth size discrepancy identifying the presence of tooth size discrepancies between the maxillary and mandibular arches is an important component of correct orthodontic diagnosis and treatment planning. to establish appropriate alignment and occlusion, the size of upper and lower front teeth, or upper and lower teeth in general, needs to be proportional. inter-arch tooth size discrepancy (itsd) is defined as a disproportion in the mesio-distal dimensions of teeth of opposing dental arches. the prevalence is clinically significant among orthodontic patients and has been reported to range from 17% to 30%. identifying inter-arch tooth size discrepancy (itsd) before treatment begins allows the practitioner to develop the treatment plan in a way that will take itsd into account. itsd corrective treatment may entail demanding reduction (interproximal wear), increase (crowns and resins), or elimination (extractions) of dental mass prior to treatment finalization. several methods have been used to determine itsd. of these methods the one most commonly used is the bolton analysis. bolton developed a method to calculate the ratio between the mesiodistal width of maxillary and mandibular teeth and stated that a correct and harmonious occlusion is possible only with adequate proportionality of tooth sizes. bolton's formula concludes that if in the anterior portion the ratio is less than 77.2% the lower teeth are too narrow, the upper teeth are too wide or there is a combination of both. if the ratio is higher than 77.2% either the lower teeth are too wide, the upper teeth are too narrow or there is a combination of both. other conditions further information: open bite malocclusion open bite treatment after eight months of braces. other kinds of malocclusions can be due to or horizontal, vertical, or transverse skeletal discrepancies, including skeletal asymmetries. increased vertical growth causes a long facial profile and commonly leads to an open bite malocclusion, while decreased vertical facial growth causes a short facial profile and is commonly associated with a deep bite malocclusion. however, there are many other more common causes for open bites (such as tongue thrusting and thumb sucking) and likewise for deep bites. the upper or lower jaw can be overgrown (macrognathia) or undergrown (micrognathia). it has been reported that patients with micrognathia are also affected by retrognathia (abnormal posterior positioning of the mandible or maxilla relative to the facial structure). these patients are majorly predisposed to a class ii malocclusion. mandibular macrognathia results in prognathism and predisposes patients to a class iii malocclusion. most malocclusion studies to date have focused on class iii malocclusions. genetic studies for class ii and class i malocclusion are more rare. an example of hereditary mandibular prognathism can be seen amongst the hapsburg royal family where one third of the affected individuals with severe class iii malocclusion had one parent with a similar phenotype the frequent presentation of dental malocclusions in patients with craniofacial birth defects also supports a strong genetic aetiology. about 150 genes are associated with craniofacial conditions presenting with malocclusions. micrognathia is a commonly recurring craniofacial birth defect appearing among multiple syndromes. for patients with severe malocclusions, corrective jaw surgery or orthognathic surgery may be carried out as a part of overall treatment, which can be seen in about 5% of the general population.