The definitive symptom of ONJ is the exposure of mandibular or maxillary bone through lesions in the gingiva that do not heal. Pain, inflammation of the surrounding soft tissue, secondary infection or drainage may or may not be present. The development of lesions is most frequent after invasive dental procedures, such as extractions, and is also known to occur spontaneously. There may be no symptoms for weeks or months, until lesions with exposed bone appear. Lesions are more common on the mandible than the maxilla.

- Pain and neuropathy

- Erythema and suppuration

- Bad breath

Osteonecrosis of the jaw (ONJ) is a severe bone disease (osteonecrosis) that affects the jaws (the maxilla and the mandible). Various forms of ONJ have been described over the last 160 years, and a number of causes have been suggested in the literature.

Osteonecrosis of the jaw associated with bisphosphonate therapy, which is required by some cancer treatment regimens, has been identified and defined as a pathological entity (bisphosphonate-associated osteonecrosis of the jaw) since 2003. The possible risk from lower oral doses of bisphosphonates, taken by patients to prevent or treat osteoporosis, remains uncertain.

Treatment options have been explored; however, severe cases of ONJ still require surgical removal of the affected bone. A thorough history and assessment of pre-existing systemic problems and possible sites of dental infection are required to help prevent the condition, especially if bisphosphonate therapy is considered.

Osteitis is inflammation of bone. More specifically, it can refer to one of the following conditions:

- Osteomyelitis, or "infectious osteitis", mainly "bacterial osteitis")

- Alveolar osteitis or "dry socket"

- Condensing osteitis (or Osteitis condensans)

- Osteitis deformans (or Paget's disease of bone)

- Osteitis fibrosa cystica (or Osteitis fibrosa, or Von Recklinghausen's disease of bone)

- Osteitis pubis

- Radiation osteitis

- Osteitis condensans ilii

- Panosteitis, a long bone condition in large breed dogs

- In horses, pedal osteitis is frequently confused with laminitis.

The signs and symptoms depend upon the type of OM, and may include:

- Pain, which is severe, throbbing and deep seated.

- Initially fistula are not present.

- No dental pain, but headache or other facial pain, as in the descriptive former term "neuralgia-inducing" (cavitational osteonecrosis).

- Fibromyalgia.

- Chronic fatigue syndrome.

- Swelling. External swelling is initially due to inflammatory edema with accompanying erythema (redness), heat and tenderness, and then later may be due to sub-periosteal pus accumulation. Eventually, subperiosteal bone formation may give a firm swelling.

- Trismus (difficulty opening the mouth), which may be present in some cases and is caused by edema in the muscles.

- Dysphagia (difficulty swallowing), which may be present in some cases and is caused by edema in the muscles.

- Cervical lymphadenitis (swelling of the lymph nodes in the neck).

- Aesthesia or paresthesia (altered sensation such as numbness or pins and needles) in the distribution of the mental nerve.

- Fever which may be present in the acute phase and is high and intermittent

- Malaise (general feeling of being unwell) which may be present in the acute phase

- Anorexia (loss of appetite).

- Leukocytosis (elevated numbers of white blood cells) which may be present in the acute phase

- Elevated erythrocyte sedimentation rate and C reactive protein are sometimes present.

- An obvious cause in the mouth (usually) such as a decayed tooth.

- Teeth that are tender to percussion, which may develop as the condition progresses

- Loosening of teeth, which may develop as the condition progresses.

- Pus may later be visible, which exudes from around the necks of teeth, from an open socket, or from other sites within the mouth or on the skin over the involved bone.

- Fetid odor.

Unlike acute OM in the long bones, acute OM in the jaws gives only a moderate systemic reaction and the person remains surprisingly well. Acute OM of the jaws may give a similar appearance to a typical odontogenic infection, but cellulitis does not tend to spread from the periosteal envelope of the involved bone. If the infection is not controlled, the process becomes chronic and systemic symptoms are usually present, including draining fistulas, loosening of teeth and sequestra formation. Untreated chronic osteomyelitis tends to feature occasional acute exacerbations.

Osteomyelitis of the jaws is osteomyelitis (which is infection and inflammation of the bone marrow, sometimes abbreviated to OM) which occurs in the bones of the jaws (i.e. maxilla or the mandible). Historically, osteomyelitis of the jaws was a common complication of odontogenic infection (infections of the teeth). Before the antibiotic era, it was frequently a fatal condition.

Former and colloquial names include Osteonecrosis of the jaws (ONJ), cavitations, dry or wet socket, and NICO (neuralgia-inducing Cavitational osteonecrosis). The current, more correct, term, osteomyelitis of the jaws, differentiates the condition from the relatively recent and better known iatrogenic phenomenon of bisphosphonate-caused Osteonecrosis of the jaws. The latter is found primarily in post-menopausal women given bisphosphonate drugs, usually against osteoporosis.

Buccal exostoses are considered different entities to osteomas (e.g. seen in Gardner syndrome), even though the two lesions are histopathologically identical.

Why buccal exostoses form is unclear, but it may involve bruxism (tooth clenching and grinding), and genetic factors. Typically they first appear in early adulthood.

By far, the two most common symptoms described are pain and the feeling that teeth no longer correctly meet (traumatic malocclusion, or disocclusion). The teeth are very sensitive to pressure (proprioception), so even a small change in the location of the teeth will generate this sensation. People will also be very sensitive to touching the area of the jaw that is broken, or in the case of condylar fracture the area just in front of the tragus of the ear.

Other symptoms may include loose teeth (teeth on either side of the fracture will feel loose because the fracture is mobile), numbness (because the inferior alveolar nerve runs along the jaw and can be compressed by a fracture) and trismus (difficulty opening the mouth).

Outside the mouth, signs of swelling, bruising and deformity can all be seen. Condylar fractures are deep, so it is rare to see significant swelling although, the trauma can cause fracture of the bone on the anterior aspect of the external auditory meatus so bruising or bleeding can sometimes be seen in the ear canal. Mouth opening can be diminished (less than 3 cm). There can be numbness or altered sensation (anesthesia/paraesthesia in the chin and lower lip (the distribution of the mental nerve).

Intraorally, if the fracture occurs in the tooth bearing area, a step may seen between the teeth on either side of the fracture or a space can be seen (often mistaken for a lost tooth) and bleeding from the gingiva in the area. There can be an open bite where the lower teeth, no longer meet the upper teeth. In the case of a unilateral condylar fracture the back teeth on the side of the fracture will meet and the open bite will get progressively greater towards the other side of the mouth.

Sometimes bruising will develop in the floor of the mouth (sublingual eccymosis) and the fracture can be moved by moving either side of the fracture segment up and down. For fractures that occur in the non-tooth bearing area (condyle, ramus, and sometimes the angle) an open bite is an important clinical feature since little else, other than swelling, may be apparent.

This type of fractured mandible can involve one condyle (unilateral) or both (bilateral). Unilateral condylar fracture may cause restricted and painful jaw movement. There may be swelling over the temporomandibular joint region and bleeding from the ear because of lacerations to the external auditory meatus. The hematoma may spread downwards and backwards behind the ear, which may be confused with Battle's sign (a sign of a base of skull fracture), although this is an uncommon finding so if present, intra-cranial injury must be ruled out. If the bones fracture and overlie each other there may be shortening of the height of the ramus. This results in gagging of the teeth on the fractured side (the teeth meet too soon on the fractured side, and not on the non fractured side, i.e. "open bite" that becomes progressively worse to the unaffected side). When the mouth is opened, there may be deviation of the mandible towards the fractured side. Bilateral condylar fractures may cause the above signs and symptoms, but on both sides. Malocclusion and restricted jaw movement are usually more severe. Bilateral body or parasymphysis fractures are sometimes termed "flail mandible", and can cause involuntary posterior movement of the tongue with subsequent obstruction of the upper airway. Displacement of the condyle through the roof of glenoid fossa and into the middle cranial fossa is rare. Bilateral condylar fractures combined with a symphyseal fracture is sometimes termed a guardsman's fracture. The name comes from this injury occurring in soldiers who faint on parade grounds and strike the floor with their chin.

Diagnosis is mostly based on general examination and radiographs, and it should be taken when abnormality of the teeth is suspected as most of the affected teeth have normal clinical appearance.

Differential diagnosis is very important to have a definitive diagnosis as some radiographic or histologic features of dentine dysplasia may bear a resemblance to different disorders:

- Dentinogenesis Imperfecta

- Odontodysplasia

- Calcinosis

- Osteogenesis imperfecta

- Ehlers Danlos syndrome

- Goldblatt syndrome

- Schimke immuno-osseous dysplasia

- Brachio-skeleto-genital syndrome.

There are no symptoms, and no signs can be elicited on examination. Medical imaging such as traditional radiography or computed tomography is required to demonstrate the defect. Usually the defect is unilateral, but occasionally can be bilateral.

Dentin dysplasia (DD) is a rare genetic developmental disorder dentine production of the teeth, commonly exhibiting an autosomal dominant inheritance that causes malformation of the root. It affects both primary and permanent dentitions in approximately 1 in every 100,000 patients. It is characterized by presence of normal enamel but atypical dentin with abnormal pulpal morphology. Witkop in 1972 classified DD into two types which are Type I (DD-1) is the radicular type, and type II (DD-2) is the coronal type. DD-1 has been further divided into 4 different subtypes (DD-1a,1b,1c,1d) based on the radiographic features.

The squamous odontogenic tumor is a rare odontogenic tumor found in any area of the alveolar bone. Usually, there is a painless swelling with adjacent teeth becoming mobile. On radiographs, it presents as a radiolucency (dark area) between the teeth in a triangular shape. Clinically, it may present similar to periodontal disease.

Lefort I - Slight swelling of the upper lip, ecchymosis is present in the buccal sulcus beneath each zygomatic arch, malocclusion, mobility of teeth. Impacted type of fractures may be almost immobile and it is only by grasping the maxillary teeth and applying a little firm pressure that a characteristic grate can be felt which is diagnostic of the fracture. Percussion of upper teeth results in cracked pot sound. Guérin's sign is present characterised by ecchymosis in the region of greater palatine vessels.

Lefort II and Lefort III (common) - Gross edema of soft tissue over the middle third of the face, bilateral circumorbital ecchymosis, bilateral subconjunctival hemorrhage, epistaxis, CSF rhinorrhoea, dish face deformity, diplopia, enophthalmos, cracked pot sound.

Lefort II - Step deformity at infraorbital margin, mobile mid face, anesthesia or paresthesia of cheek.

Lefort III - Tenderness and separation at frontozygomatic suture, lengthening of face, depression of ocular levels (enophthalmos), hooding of eyes, and tilting of occlusal plane, an imaginary curved plane between the edges of the incisors and the tips of the posterior teeth. As a result, there is gagging on the side of injury.

The Stafne defect (also termed Stafne's idiopathic bone cavity, Stafne bone cavity, Stafne bone cyst (misnomer), lingual mandibular salivary gland depression, lingual mandibular cortical defect, latent bone cyst, or static bone cyst) is a depression of the mandible on the lingual surface (the side nearest the tongue). The Stafne defect is thought to be a normal anatomical variant, as the depression is created by ectopic salivary gland tissue associated with the submandibular gland and does not represent a pathologic lesion as such.

A Le Fort fracture of the skull is a classic transfacial fracture of the midface, involving the maxillary bone and surrounding structures in either a horizontal, pyramidal or transverse direction. The hallmark of Lefort fractures is traumatic "pterygomaxillary separation", which signifies fractures between the pterygoid plates, horseshoe shaped bony protuberances which extend from the inferior margin of the maxilla, and the maxillary sinuses. Continuity of this structure is a keystone for stability of the midface, involvement of which impacts surgical management of trauma victims, as it requires fixation to a horizontal bar of the frontal bone. The pterygoid plates lie posterior to the upper dental row, or alveolar ridge, when viewing the face from an anterior view. The fractures are named after French surgeon René Le Fort (1869–1951), who discovered the fracture patterns by examining crush injuries in cadavers.

Since alveolar osteitis is not primarily an infection, there is not usually any pyrexia (fever) and cervical lymphadenitis (swollen glands in the neck), and only minimal edema (swelling) and erythema (redness) is present in the soft tissues surrounding the socket.

Signs may include:

- An empty socket, which is partially or totally devoid of blood clot. Exposed bone may be visible or the socket may be filled with food debris which reveals the exposed bone once it is removed. The exposed bone is extremely painful and sensitive to touch. Surrounding inflamed soft tissues may overlie the socket and hide the dry socket from casual examination.

- Denuded (bare) bone walls.

Symptoms may include:

- Dull, aching, throbbing pain in the area of the socket, which is moderate to severe and may radiate to other parts of the head such as the ear, eye, temple and neck. The pain normally starts on the second to fourth day after the extraction, and may last 10–40 days. The pain may be so strong that even strong analgesics do not relieve it.

- Intraoral halitosis (oral malodor).

- Bad taste in the mouth.

Tooth ankylosis refers to a fusion (ankylosis) of teeth to bone. The condition is diagnosed with radiographs (X-rays), which show loss of the periodontal ligament space and blending of the root with the bone. Clinically the tooth sounds solid when percussed (tapped) compared to the dull, cushioned sound from normal teeth. Ankylosis of teeth is uncommon, more so in deciduous teeth than permanent teeth.

Alveolar osteitis is inflammation of the alveolar bone (i.e., the alveolar process of the maxilla or mandible). Classically, this occurs as a postoperative complication of tooth extraction.

Alveolar osteitis usually occurs where the blood clot fails to form or is lost from the socket (i.e., the defect left in the gum when a tooth is taken out). This leaves an empty socket where bone is exposed to the oral cavity, causing a localized alveolar osteitis limited to the lamina dura (i.e., the bone which lines the socket). This specific type of alveolar osteitis is also known as dry socket or, less commonly, fibrinolytic alveolitis, and is associated with increased pain and delayed healing time.

Dry socket occurs in about 0.5–5% of routine dental extractions, and in about 25–30% of extractions of impacted mandibular third molars (wisdom teeth which are buried in the bone).

Prognathism in humans can be due to normal variation among phenotypes. In human populations where prognathism is not the norm, it may be a malformation, the result of injury, a disease state or a hereditary condition. Prognathism is considered a disorder only if it affects mastication, speech or social function as a byproduct of severely affected aesthetics of the face.

Clinical determinants include soft tissue analysis where the clinician assesses nasolabial angle, the relationship of the soft tissue portion of the chin to the nose, and the relationship between the upper and lower lips; also used is dental arch relationship assessment such as Angle's classification.

Cephalometric analysis is the most accurate way of determining all types of prognathism, as it includes assessments of skeletal base, occlusal plane angulation, facial height, soft tissue assessment and anterior dental angulation. Various calculations and assessments of the information in a cephalometric radiograph allow the clinician to objectively determine dental and skeletal relationships and determine a treatment plan.

Prognathism is less prevalent in East Asians and Caucasians. It is not to be confused with micrognathism, although combinations of both may be found. It affects the middle third of the face, causing it to jut out, thereby increasing the facial area, similar in phenotype of archaic hominids and apes. Mandibular prognathism is a protrusion of the mandible, affecting the lower third of the face. Alveolar prognathism is a protrusion of that portion of the maxilla where the teeth are located, in the dental lining of the upper jaw. Prognathism can also be used to describe ways that the maxillary and mandibular dental arches relate to one another, including malocclusion (where the upper and lower teeth do not align). When there is maxillary and/or alveolar prognathism which causes an alignment of the maxillary incisors significantly anterior to the lower teeth, the condition is called an overjet. When the reverse is the case, and the lower jaw extends forward beyond the upper, the condition is referred to as retrognathia (reverse overjet).

Periodontosis is an obsolete term that was used to describe what was once thought to be certain type of unique and distinguishable chronic periodontal disease that manifested as degenerative bony changes without concomitant inflammation. Although utilized for more than 50 years, the term has since been dropped in favor of a more contemporary disease classification for periodontal disease.

Described by Gottlieb as a "diffuse atrophy of the alveolar bone," the term "periodontosis" was later applied and it gained acceptance as a disease entity, being defined as:

Noted as a rare disease, periodontosis was said to have been seen primarily in young patients. And despite being defined as being a "noninflammatory destruction of the periodontium," almost all cases did exhibit varying degrees of gingival inflammation.

Periapical cysts begin as asymptomatic and progress slowly. Subsequent infection of the cyst causes swelling and pain. Initially, the cyst swells to a round hard protrusion, but later on the body resorbs some of the cyst wall, leaving a softer accumulation of fluid underneath the mucous membrane.

Larger cysts may cause bone expansion or displace roots. Discoloration of the affected tooth may also occur. Patient will present negative results to electric and ice test of the affected tooth but will be sensitive to percussion. Surrounding gingival tissue may experience lymphadenopathy. The alveolar plate may exhibit crepitus when palpated.

Periapical cysts exist in two structurally distinct classes:

Periapical true cysts - cysts containing cavities entirely surrounded in epithelial lining. Resolution of this type of cyst requires surgical treatment such as a cystectomy.

Periapical pocket cysts - epithelium lined cavities that have an opening to the root canal of the affected tooth. Resolution may occur after traditional root canal therapy.

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.

Prognathism is the positional relationship of the mandible or maxilla to the skeletal base where either of the jaws protrudes beyond a predetermined imaginary line in the coronal plane of the skull. In general dentistry, oral and maxillofacial surgery and orthodontics, this is assessed clinically or radiographically (cephalometrics). The word "prognathism" derives from Greek "pro" ("forward") and γνάθος "gnáthos" ("jaw"). One or more types of prognathism may result in the common condition of malocclusion, in which an individual's top teeth and lower teeth do not align properly.

Peripheral giant-cell granulomas appear microscopically as a large number of multinucleated giant cells, which can have up to dozens of nuclei. Additionally, there are mesenchymal cells that are ovoid and spindle-shaped. Near the borders of the lesion, deposits of hemosiderin and hemorrhage is often found. In 50% of cases, ulcerations are present.