Malocclusion is a common finding, although it is not usually serious enough to require treatment. Those who have more severe malocclusions, which present as a part of Craniofacial Anomalies, may require orthodontic and sometimes surgical treatment (orthognathic surgery) to correct the problem. Correction of malocclusion may reduce risk of tooth decay and help relieve excessive pressure on the temporomandibular joint. Orthodontic treatment is also used to align for aesthetic reasons.

Malocclusions may be coupled with skeletal disharmony of the face, where the relations between the upper and lower jaws are not appropriate. Such skeletal disharmonies often distort sufferer's face shape, severely affect aesthetics of the face, and may be coupled with mastication or speech problems. Most skeletal malocclusions can only be treated by orthognathic surgery.

Dental open bite occurs in patients where the anterior teeth fail to touch. However, this is not accompanied by the skeletal tendency of having an open bite. Thus this type of open bite may happen in patients who have horizontal or hypodivergent growth pattern. These patients have normal jaw growth and do not have the long face syndrome. The anterior open bite in these patients may be caused by Macroglossia, Tongue thrusting habit or digit sucking habits. Some of the characteristics of a dental open bite include:

- Normal lower anterior facial height

- Horizontal/Hypodivergent growth pattern

- Occlusal plane diverges after the premolar contact

- Under-eruption of the anterior incisors

- Over-eruption of the posterior incisors

- Proclined upper and lower incisors

- No vertical maxillary excess or gummy smile

- Presence of habits such as thumb sucking, tongue thrusting

- Spacing between anterior incisors due to their proclination

Open bite malocclusion can happen due to several reasons. It may be genetic in nature, leading to a skeletal open bite or can be caused by functional habits which may lead to dental open bite. In the earlier age, open bite may occur due to a transitional change from primary to the permanent dentition. Some factors that may cause an open bite are:

- Tongue thrusting

- Thumb sucking

- Long-term usage of Pacifier

- Macroglossia

- Airway obstruction

- Adenoid hypertrophy

- Nasal concha Hypertrophy

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.

Depending on the sagittal relations of teeth and jaws, malocclusions can be divided mainly into three types according to Angle's classification system published 1899. However, there are also other conditions, e.g. "crowding of teeth", not directly fitting into this classification.

Many authors have tried to modify or replace Angle's classification. This has resulted in many subtypes and new systems (see section below: "Review of Angle's system of classes").

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.

Retrognathia (or retrognathism) is a type of malocclusion which refers to an abnormal posterior positioning of the maxilla or mandible, particularly the mandible, relative to the facial skeleton and soft tissues.

A retrognathic mandible is commonly referred to as an overbite, though this terminology is not used medically.

Temporomandibular joint pain is generally due to one of four reasons.

- Myofascial pain dysfunction syndrome, primarily involving the muscles of mastication. This is the most common cause.

- Internal derangements, an abnormal relationship of the disc to any of the other components of the joint. Disc displacement is an example of internal derangement.

- Osteoarthritis of the temporomandibular joint, a degenerative joint disease of the articular surfaces.

- Temporal arteritis, for which it is considered a reliable diagnostic criteria.

Pain or dysfunction of the temporomandibular joint is sometimes referred to as "TMJ", and temporomandibular joint disorder (or "dysfunction") may be abbreviated TMD. This term is used to refer to a group of problems involving the temporomandibular joints and the muscles, tendons, ligaments, blood vessels, and other tissues associated with them.

Although rare, other pathologic conditions may also affect the function of temporomandibular joints, causing pain and swelling. These conditions include chondrosarcoma, osteosarcoma, giant cell tumor and aneurysmal bone cyst.

Successful treatments have shown that causes are functional rather than physical: that is, most lisps are caused by errors in tongue placement within the mouth rather than caused by any injury or congenital deformity to the mouth. The most frequently discussed of these problems is tongue thrust in which the tongue protrudes beyond the front teeth. This protrusion affects speech as well as swallowing and can lead to lisping. Ankyloglossia or tongue tie can also be responsible for lisps in children.

However, it is unclear whether these deficiencies are caused by the tongue tie itself or the muscle weakness following the correction of the tongue tie. Overbites and underbites may also contribute to non lingual lisping. Temporary lisps can be caused by dental work, dental appliances such as dentures or retainers or by swollen or bruised tongues.

The most common disorder of a temporomandibular joint is disc displacement. In essence, this is when the articular disc, attached anteriorly to the superior head of the lateral pterygoid muscle and posteriorly to the retrodiscal tissue, moves out from between the condyle and the fossa, so that the mandible and temporal bone contact is made on something other than the articular disc. This, as explained above, is usually very painful, because unlike these adjacent tissues, the central portion of the disc contains no sensory innervation.

In most instances of disorder, the disc is displaced anteriorly upon translation, or the anterior and inferior sliding motion of the condyle forward within the fossa and down the articular eminence. On opening, a "pop" or "click" can sometimes be heard and usually felt also, indicating the condyle is moving back onto the disk, known as "reducing the joint" (disc displacement with reduction). Upon closing, the condyle will slide off the back of the disc, hence another "click" or "pop" at which point the condyle is posterior to the disc. Upon clenching, the condyle compresses the bilaminar area, and the nerves, arteries and veins against the temporal fossa, causing pain and inflammation.

In disc displacement without reduction the disc stays anterior to the condylar head upon opening. Mouth opening is limited and there is no "pop" or "click" sound on opening.

A lisp, also known as sigmatism, is a speech impediment in which a person misarticulates sibilants (, , , ), (, , , ). These misarticulations often result in unclear speech.

Lachiewicz–Sibley syndrome is a rare autosomal dominant disorder characterized by preauricular pits and renal disease. Persons with this disease may have hypoplasic kidneys or proteinuria. This disease was first described in a Caucasian family of British and Irish descent that emigrated to Ohio in the 19th century before settling in Nebraska. Many of the members of this family still live in Nebraska, although the relatives are now scattered throughout the country.

Unlike branchio-oto-renal (BOR) syndrome, Lachiewicz–Sibley syndrome is characterized by only preauricular pitting and renal disease. Persons with BOR syndrome also present with hearing loss, branchial fistulas or cysts, malformed ears, and lacrimal stenosis. Other anomalies in BOR syndrome may include a long narrow face, a deep overbite, and facial paralysis.

It was characterized in 1985.

Most of the readily visible signs are associated with the skeletal system. Many individuals with Marfan syndrome grow to above-average height, and some have disproportionately long, slender limbs with thin, weak wrists and long fingers and toes. Besides affecting height and limb proportions, people with Marfan syndrome may have abnormal lateral curvature of the spine (scoliosis), thoracic lordosis, abnormal indentation (pectus excavatum) or protrusion (pectus carinatum) of the sternum, abnormal joint flexibility, a high-arched palate with crowded teeth and an overbite, flat feet, hammer toes, stooped shoulders, and unexplained stretch marks on the skin. It can also cause pain in the joints, bones and muscles. Some people with Marfan have speech disorders resulting from symptomatic high palates and small jaws. Early osteoarthritis may occur. Other signs include limited range of motion in the hips due to the femoral head protruding into abnormally deep hip sockets.

Dural ectasia, the weakening of the connective tissue of the dural sac encasing the spinal cord, can result in a loss of quality of life. It can be present for a long time without producing any noticeable symptoms. Symptoms that can occur are lower back pain, leg pain, abdominal pain, other neurological symptoms in the lower extremities, or headachessymptoms which usually diminish when lying flat. On X-ray however dural ectasia is not often visible in the early stages. A worsening of symptoms might warrant an MRI of the lower spine. Dural ectasia that has progressed to this stage would appear in an MRI as a dilated pouch wearing away at the lumbar vertebrae. Other spinal issues associated with Marfan syndrome include degenerative disc disease, spinal cysts and dysfunction of the autonomic nervous system.