Behavior therapy is important especially when the kids are in their primary dentition in the pre-adolescent age. Improving habits at this time may lead to self-correction of open bite in many cases. Sometimes presence of infantile swallowing into early childhood may lead to an anterior open bite in patients. Habit control through appliances such as Tongue crib or Tongue spurs may be used in adolescent ages if the behavior modification fails to stop the habit.

Extra teeth, lost teeth, impacted teeth, or abnormally shaped teeth have been cited as causes of malocclusion. A small underdeveloped jaw, caused by lack of masticatory stress during childhood, can cause tooth overcrowding. Ill-fitting dental fillings, crowns, appliances, retainers, or braces as well as misalignment of jaw fractures after a severe injury are other causes. Tumors of the mouth and jaw, thumb sucking, tongue thrusting, pacifier use beyond age 3, and prolonged use of a bottle have also been identified as causes.

In an experiment on two groups of rock hyraxes fed hardened or softened versions of the same foods, the animals fed softer food had significantly narrower and shorter faces and thinner and shorter mandibles than animals fed hard food. Experiments have shown similar results in other animals, including primates, supporting the theory that masticatory stress during childhood affects jaw development. Several studies have shown this effect in humans. Children chewed a hard resinous gum for two hours a day and showed increased facial growth.

During the transition to agriculture, the shape of the human mandible went through a series of changes. The mandible underwent a complex series of shape changes not matched by the teeth, leading to incongruity between 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."

Literature states that very few crossbites tend to self-correct which often justify the treatment approach of correcting these bites as early as possible. Only 0–9% of crossbites self-correct. Lindner et al. reported that in a 50% of crossbites were corrected in 76 four year old children.

An anterior open bite occurs in humans when the front teeth fail to touch and there is no overlap between upper incisors and lower incisors. Anterior open can be caused by functional habits such as digit sucking, tongue thrust or long-term pacifier use. When digit sucking habit is present in the late primary to early mixed dentition stages, it can lead to different side-effects such as upper teeth flaring out, lower teeth flaring in, increase in the open bite and the overjet. A posterior crossbite in these children along with decrease in intercanine and intermolar width is also found. The more intense (longer) the habit, the worse the malocclusion may be.

Pacifier use has also shown to cause anterior open bites in children. Pacifier use which lasts longer than 18 months, may cause this malocclusion. It is shown that as long as the sucking habit stops before the eruption of permanent teeth, the open bite self-corrects. In some cases, behavior modification may be necessary to eliminate the dental habits. If all else fails, then a tongue crib can be used.

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.

Crossbite is a form of malocclusion where a tooth (or teeth) has a more buccal or lingual position (that is, the tooth is either closer to the cheek or to the tongue) than its corresponding antagonist tooth in the upper or lower dental arch. In other words, crossbite is a lateral misalignment of the dental arches.

Overbite medically refers to the extent of vertical (superior-inferior) overlap of the maxillary central incisors over the mandibular central incisors, measured relative to the incisal ridges.

The term overbite does not refer to a specific condition, nor is it a form of malocclusion. Rather an absent or excess overbite would be a malocclusion. Normal overbite is not measured in exact terms, but as a proportion (approximately 30–50% of the height of the mandibular incisors) and is commonly expressed as a percentage.

In disease states, maxillary prognathism is associated with Cornelia de Lange syndrome; however, so-called false maxillary prognathism, or more accurately, retrognathism, where there is a lack of growth of the mandible, is by far a more common condition.

Prognathism, if not extremely severe, can be treated in growing patients with orthodontic functional or orthopaedic appliances. In adult patients this condition can be corrected by means of a combined surgical/orthodontic treatment, where most of the time a mandibular advancement is performed. The same can be said for mandibular prognathism.

Not all alveolar prognathism is anomalous, and significant differences can be observed among different ethnic groups.

Harmful habits such as thumb sucking or tongue thrusting can result in or exaggerate an alveolar prognathism, causing teeth to misalign. Functional appliances can be used in growing children to help modify bad habits and neuro-muscular function, with the aim of correcting this condition.

Alveolar prognathism can also easily be corrected with fixed orthodontic therapy. However, relapse is quite common, unless the cause is removed or a long-term retention is used.

Management of teeth with PFE can include extractions of affected teeth, followed by orthodontic space closure or placement of a prosthetic implant with a bone graft. This option can only be applied to a single tooth that is affected. If multiple teeth are affected then, a segmental osteotomy may be performed to bring the entire segment into occlusion. However, minimal success has been shown following this procedure. These teeth usually are "non-responsive" to the orthodontic force and studies have shown that ankylosis of these teeth can occur if force applied.

There have been many syndromes which have been identified to be related to failure of eruption of teeth. These syndromes are Cleidocranial dyspalsia, Osteoporosis, Rutherford syndrome, GAPO syndrome and Osteoglophonic dysplasia.

Overbite is often confused with overjet, which is the distance between the maxillary anterior teeth and the mandibular anterior teeth in the anterior-posterior axis.

"Overbite" may also be used commonly to refer to Class II malocclusion or retrognathia, though this usage can be considered incorrect. This is where the mesiobuccal cusp of the maxillary first molar is situated anterior to the buccal groove of the mandibular first molar; in other words, the mandible (lower jaw) appears too far behind the maxilla. A person presenting with Class II malocclusion may exhibit excessive overbite as well, or may have the opposite problem, which is referred to as openbite (or apertognathia). In the case of apertognathia, the teeth do not overlap enough or at all. The upper teeth protrude past the lower teeth.

Amelogenesis imperfecta hypomaturation type with taurodontism are often confused. Amelogenesis imperfecta of the hypomaturation type with taurodontism (AIHHT) has no hair or bone changes which helps to differentiate between TDO cases and AIHHT. Polymerase chain reaction also known as PCR is used to amply pieces of DNA and observed for the 141 base pair allele as a result of a deletion of four nucleotides in exon 3 of the DLX-3 gene. Additionally, the current research shows that there is heavy reliance on the physical characteristics in the differentiation of TDO verses AIHHT and the severity and prevalence of their expression. For instance, taurodontism is severely expressed in TDO, but mildly expressed in AIHHT. Currently, researchers are trying to identify the reason for the alteration in the DLX-3 and DLX-7 genes that are responsible for AIHHT versus TDO.

The adaptation from nasal to mouth breathing takes pace when changes such as chronic middle ear infections, sinusitis, allergic rhinitis, upper airway infections, and sleep disturbances (e.g., snoring) take place. In addition, mouth breathing is often associated with a decrease in oxygen intake into the lungs. Mouth breathing can particularly affect the growing face, as the abnormal pull of these muscle groups on facial bones slowly deforms these bones, causing misalignment. The earlier in life these changes take place, the greater the alterations in facial growth, and ultimately an open mouth posture is created where the upper lip is raised and the lower jaw is maintained in an open posture. The tongue, which is normally tucked under the roof of the mouth, drops to the floor of the mouth and protrudes to allow a greater volume of air intake. Consequently, an open mouth posture can lead to malocclusions and problems in swallowing. Other causes of open-mouth posture are weakness of lip muscles, overall lack of tone in the body or hypotonia, and prolonged/chronic allergies of the respiratory tract. A.union

A single copy of the abnormal gene from one parent is able to cause the disease; this is called autosomal dominance. A mutation in the DLX3 gene has been confirmed as the cause of TDO. The onset of TDO begins with a 4 base pair deletion on chromosome 17q21, causing a mutation, specifically frameshift, and the termination codon to be the cause of the lack of complete maturation of the tooth enamel; this mutation is also responsible for the osseous defects in the bone. DLX-3 is expressed in the placenta and is significantly important during embryonic development in regards to hard bone tissue which is present in the teeth, skull, and long bones such as in the arms and legs. During normal tooth development, DLX 3 shifts from predominant expression in the inner enamel epithelium; the outer layer does not express DLX 3. In TDO cases, the DLX-3 is present on the outer enamel epithelium and leads to the dental abnormalities seen in this disease. Improper expression of DLX-3 causes the tooth enamel to be thinner, which leads to attrition and is most often the cause of dental abscess seen in TDO persons.

During osseous, connective tissue, and dermal cell differentiation, DLX 3 in TDO is also responsible for upper cranial thickness, calvaria, osteosclerosis of the long bones, long narrow head (dolichocephaly), abnormally thin brittle nails, and premature closing of fibrous joints. Consequently, 95% of people with TDO that are 16 years old or younger show skeletal abnormalities before full maturation takes place. Lack of mastoid pneumatization by mastoid cells occurs in 82% of the cases and is rarely prevalent outside of TDO diagnosis. Mastoid pneumatization occurs at about 6 months of ages and acts to minimize pressure fluctuations in the Eustachian tubes of the ear. The mastoid lies posterior to the lower jawbone (mandible) and distal to the ear. The Eustachian tube connects the middle ear to the back of the nose, and acts to create a specific pressure in the ear canal that causes vibrations to the eardrum; if adequate pressure is not attained, muffled, dull hearing results. In addition to the mastoid pneumatization assisting the Eustachian tubes for normal hearing, lack of mastoid pneumatization causes inflammation of the ear, general irritation, and does not allow enough air in to assist with mucus flowing out. It is not completely understood why gene mutations occur, but it is known that genetic mutations that cause disease are acquired from either or both parents at fertilization.

Repair with cementum or dentin occurs after partial root resorption, fusing the tooth with the bone. It may occur following dental trauma, especially occlusal trauma, or after periapical periodontitis caused by pulp necrosis. Ankylosis itself is not a reason to remove a permanent tooth, however teeth which must be removed for other reasons are made significantly more difficult to remove if they are ankylosed.

Orofacial myofunctional disorders (OMD) (sometimes called “oral myofunctional disorder", and “tongue thrust”) are muscle disorders of the face, mouth, lips, or jaw.

Recent studies on incidence and prevalence of tongue thrust behaviors are not available. However, according to the previous research, 38% of various populations have OMD. The incidence is as high as 81% in children exhibiting speech/articulation problems (Kellum, 1992).

Ankylosis of deciduous teeth ("submerged teeth") may rarely occur. The most commonly affected tooth is the mandibular (lower) second deciduous molar. Partial root resorption first occurs and then the tooth fuses to the bone. This prevents normal exfoliation of the deciduous tooth and typically causes impaction of the permanent successor tooth. As growth of the alveolar bone continues and the adjacent permanent teeth erupt, the ankylosed deciduous tooth appears to submerge into the bone, although in reality it has not changed position. Treatment is by extraction of the involved tooth, to prevent malocclusion, periodontal disturbance or dental caries.

Preventive and restorative dental care is very important as well as considerations for esthetic issues since the crown are yellow from exposure of dentin due to enamel loss. The main objectives of treatment is pain relief, preserving patient's remaining dentition, and to treat and preserve the patient's occlusal vertical height.

Many factors are to be considered to decide on treatment options such as the classification and severity of AI, the patient's social history, clinical findings etc. There are many classifications of AI but the general management of this condition is similar.

Full-coverage crowns are sometimes being used to compensate for the abraded enamel in adults, tackling the sensitivity the patient experiences. Usually stainless steel crowns are used in children which may be replaced by porcelain once they reach adulthood. These aid with maintaining occlusal vertical dimension.

Aesthetics may be addressed via placement of composite or porcelain veneers, depending on patient factors eg age. If the patient has primary or mixed dentition, lab-made composite veneers may be provided temporarily, to be replaced by permanent porcelain veneers once the patient has stabilized permanent dentition. The patient's oral hygiene and diet should be controlled as well as they play a factor in the success of retaining future restorations.

In the worst-case scenario, the teeth may have to be extracted and implants or dentures are required. Loss of nerves in the affected teeth may occur.

Prosthetic replacement of missing teeth is possible using dental implant technology or dentures. This treatment can be successful in giving patients with anodontia a more aesthetically pleasing appearance. The use of an implant prosthesis in the lower jaw could be recommended for younger patients as it is shown to significantly improve the craniofacial growth, social development and self-image. The study associated with this evidence worked with individuals who had ectodermal dysplasia of varying age groups of up to 11, 11 to 18 and more than 18 years. It was noted that the risk of implant failure was significantly higher in patients younger than 18 years, but there is significant reason to use this methodology of treatment in those older. Overall the use of an implant-prosthesis has a considerable functional, aesthetic and psychological advantage when compared to a conventional denture, in the patients.

Mandible fracture causes vary by the time period and the region studied. In North America, blunt force trauma (a punch) is the leading cause of mandible fracture whereas in India, motor vehicle collisions are now a leading cause. On battle grounds, it is more likely to be high velocity injuries (bullets and shrapnel). Prior to the routine use of seat belts, airbags and modern safety measures, motor vehicle collisions were a leading cause of facial trauma. The relationship to blunt force trauma explains why 80% of all mandible fractures occur in males. Mandibular fracture is a rare complication of third molar removal, and may occur during the procedure or afterwards. With respect to trauma patients, roughly 10% have some sort of facial fracture, the majority of which come from motor vehicle collisions. When the person is unrestrained in a car, the risk of fracture rises 50% and when an unhelmeted motorcyclist the risk rises 4-fold.

Overjet is the extent of horizontal (anterior-posterior) overlap of the maxillary central incisors over the mandibular central incisors. In class II (division I) malocclusion the overjet is increased as the maxillary central incisors are protruded.

In dentistry, anodontia, also called anodontia vera, is a rare genetic disorder characterized by the congenital absence of all primary or permanent teeth. It is associated with the group of skin and nerve syndromes called the ectodermal dysplasias. Anodontia is usually part of a syndrome and seldom occurs as an isolated entity.

Congenital absence of permanent teeth can present as hypodontia, usually missing 1 or 2 permanent teeth, or oligodontia that is the congenital absence of 6 or more teeth. Congenital absence of all wisdom teeth, or third molars, is relatively common. Anodontia is the congenital absence of teeth and can occur in some or all teeth (partial anodontia or hypodontia), involve two dentitions or only teeth of the permanent dentition (Dorland's 1998). Approximately 1% of the population suffers from oligodontia. Many denominations are attributed to this anomaly: partial anodontia, hypodontia, oligodontia, the congenital absence, anodontia, bilateral aplasia. Anodontia being the term used in controlled vocabulary Medical Subject Headings (MeSH) from MEDLINE which was developed by the United States National Library of Medicine. The congenital absence of at least one permanent tooth is the most common dental anomaly and may contribute to masticator dysfunction, speech impairment, aesthetic problems, and malocclusion (Shapiro and Farrington 1983). Absence of lateral incisors represents a major stereotype. Individuals with this condition are perceived as socially most aggressive compared with people without anodontia (Shaw 1981).

Amelogenesis imperfecta (AI) is a congenital disorder that presents with a rare abnormal formation of the enamel or external layer of the crown of teeth, unrelated to any systemic or generalized conditions. Enamel is composed mostly of mineral, that is formed and regulated by the proteins in it. Amelogenesis imperfecta is due to the malfunction of the proteins in the enamel (ameloblastin, enamelin, tuftelin and amelogenin) as a result of abnormal enamel formation via amelogenesis.

People afflicted with amelogenesis imperfecta have teeth with abnormal color: yellow, brown or grey; this disorder can afflict any number of teeth of both dentitions. The teeth have a lower risk for dental cavities and are hypersensitive to temperature changes as well as rapid attrition, excessive calculus deposition, and gingival hyperplasia.

Macroglossia is uncommon, and usually occurs in children. Macroglossia has been reported to have a positive family history in 6% of cases. The National Organization of Rare Disorders lists macroglossia as a rare disease (less than 200 000 individuals in the US).