Osteonecrosis of the jaw is classified based on severity, number of lesions, and lesion size. Osteonecrosis of greater severity is given a higher grade, with asymptomatic ONJ designated as grade 1 and severe ONJ as grade 4.

The treatment should be tailored to the cause involved and the severity of the disease process. With oral osteoporosis the emphasis should be on good nutrient absorption and metabolic wastes elimination through a healthy gastro-intestinal function, effective hepatic metabolism of toxicants such as exogenous estrogens, endogenous acetaldehyde and heavy metals, a balanced diet, healthy lifestyle, assessment of factors related to potential coagulopathies, and treatment of periodontal diseases and other oral and dental infections.

In cases of advanced oral ischaemic osteoporosis and/or ONJ that are not bisphosphonates related, clinical evidence has shown that surgically removing the damaged marrow, usually by curettage and decortication, will eliminate the problem (and the pain) in 74% of patients with jaw involvement. Repeat surgeries, usually smaller procedures than the first, may be required. Almost a third of jawbone patients will need surgery in one or more other parts of the jaws because the disease so frequently present multiple lesions, i.e., multiple sites in the same or similar bones, with normal marrow in between. In the hip, at least half of all patients will get the disease in the opposite hip over time; this pattern occurs in the jaws as well. Recently, it has been found that some osteonecrosis patients respond to anticoagulation therapies alone. The earlier the diagnosis the better the prognosis. Research is ongoing on other non-surgical therapeutic modalities that could alone or in combination with surgery further improve the prognosis and reduce the morbidity of ONJ. A greater emphasis on minimizing or correcting known causes is necessary while further research is conducted on chronic ischaemic bone diseases such as oral osteoporosis and ONJ.

In patients with bisphosphonates-associated ONJ, the response to surgical treatment is usually poor. Conservative debridement of necrotic bone, pain control, infection management, use of antimicrobial oral rinses, and withdrawal of bisphosphonates are preferable to aggressive surgical measures for treating this form of ONJ. Although an effective treatment for bisphosphonate-associated bone lesions has not yet been established, and this is unlikely to occur until this form of ONJ is better understood, there have been clinical reports of some improvement after 6 months or more of complete cessation of bisphosphonate therapy.

Usual diagnosis is via radiograph, patient history, biopsy is rarely needed. Periodic follow ups should included additional radiographs that show minimal growth or regression.

Culture and sensitivity of the wound site determines the choice of antibiotic. Repeated culture and sensitivity testing is often carried out in OM since the treatment is prolonged and antibiotic resistance may occur, when a change in the drug may be required.

Pathologic fracture of the mandible is a possible complication of OM where the bone has been weakened significantly.

Computed tomography is the most sensitive and specific of the imaging techniques. The facial bones can be visualized as slices through the skeletal in either the axial, coronal or sagittal planes. Images can be reconstructed into a 3-dimensional view, to give a better sense of the displacement of various fragments. 3D reconstruction, however, can mask smaller fractures owing to volume averaging, scatter artifact and surrounding structures simply blocking the view of underlying areas.

Research has shown that panoramic radiography is similar to computed tomography in its diagnostic accuracy for mandible fractures and both are more accurate than plain film radiograph. The indications to use CT for mandible fracture vary by region, but it does not seem to add to diagnosis or treatment planning except for comminuted or avulsive type fractures, although, there is better clinician agreement on the location and absence of fractures with CT compared to panoramic radiography.

There are various classification systems of mandibular fractures in use.

In the early stages, bone scintigraphy and MRI are the preferred diagnostic tools.

X-ray images of avascular necrosis in the early stages usually appear normal. In later stages it appears relatively more radio-opaque due to the nearby living bone becoming resorbed secondary to reactive hyperemia. The necrotic bone itself does not show increased radiographic opacity, as dead bone cannot undergo bone resorption which is carried out by living osteoclasts. Late radiographic signs also include a radiolucency area following the collapse of subchondral bone (crescent sign) and ringed regions of radiodensity resulting from saponification and calcification of marrow fat following medullary infarcts.

A variety of methods may be used to treat the most common being the total hip replacement (THR). However, THRs have a number of downsides including long recovery times and short life spans (of the hip joints). THRs are an effective means of treatment in the older population; however, in younger people they may wear out before the end of a person's life.

Other technicques such as metal on metal resurfacing may not be suitable in all cases of avascular necrosis; its suitability depends on how much damage has occurred to the femoral head. Bisphosphonates which reduces the rate of bone breakdown may prevent collapse (specifically of the hip) due to AVN.

Treatment of condylar resorption is controversial. Orthognathic surgery may be done to reconstruct and stabilize the condyles and disc of the temporomandibular joint. Anti-infammatory medication is also used to slow the resorption process. Orthodontics may be used to treat the occlusion. Arthrocentesis, and arthroscopic surgery are also sometimes used to treat disc displacement and other symptoms.

Well defined, rounded or triangular radiodensity, that is uniformly opaque. There is no lucent component. Found near the root apex or in the inter-radicular area. Root resorption and tooth movement are rare.

X-rays of the hip may suggest and/or verify the diagnosis. X-rays usually demonstrate a flattened, and later fragmented, femoral head. A bone scan or MRI may be useful in making the diagnosis in those cases where X-rays are inconclusive. Usually, plain radiographic changes are delayed 6 weeks or more from clinical onset, so bone scintigraphy and MRI are done for early diagnosis. MRI results are more accurate, i.e. 97 to 99% against 88 to 93% in plain radiography. If MRI or bone scans are necessary, a positive diagnosis relies upon patchy areas of vascularity to the capital femoral epiphysis (the developing femoral head).

Generally buccal exostoses require no treatment. However, they may be easily traumatized causing ulceration, or may contribute to periodontal disease if they become too large, or can interfere with wearing a denture (false teeth). If they are creating problems, they are generally removed with a simple surgical procedure under local anesthetic.

Distal clavicular osteolysis (DCO) is often associated with problems weightlifters have with their acromioclavicular joints due to high stresses put on the clavicle as it meets with the acromion. This condition is often referred to as "weight lifter's shoulder". Medical ultrasonography readily depicts resorption of the distal clavicle as irregular cortical erosions, whereas the acromion remains intact. Associated findings may include distended joint capsule, soft-tissue swelling, and joint instability.

A common surgery to treat recalcitrant DCO is re-sectioning of the distal clavicle, removing a few millimetres of bone from the very end of the bone.

While bone resorption is commonly associated with many diseases or joint problems, the term "osteolysis" generally refers to a problem common to artificial joint replacements such as total hip replacements, total knee replacements and total shoulder replacements. Osteolysis can also be associated with the radiographic changes seen in those with bisphosphonate-related osteonecrosis of the jaw.

There are several biological mechanisms which may lead to osteolysis. In total hip replacement, the generally accepted explanation for osteolysis involves wear particles (worn off the contact surface of the artificial ball and socket joint). As the body attempts to clean up these wear particles (typically consisting of plastic or metal), it triggers an autoimmune reaction which causes resorption of living bone tissue. Osteolysis has been reported to occur as early as 12 months after implantation and is usually progressive. This may require a revision surgery (replacement of the prosthesis).

Although osteolysis itself is clinically asymptomatic, it can lead to implant loosening or bone breakage, which in turn causes serious medical problems.

They are more common in males than females, occurring in a ratio of about 5:1. They are strongly associated with the presence of torus mandibularis and torus palatinus.

Osteoradionecrosis is a possible complication following radiotherapy where an area of bone does not heal from irradiation. Irradiation of bones causes damage to osteocytes and impairs the blood supply. The affected hard tissues become hypovascular (reduced number of blood vessels), hypocellular (reduced number of cells) and hypoxic (low levels of oxygen). Osteoradionecrosis usually occurs in the mandible, and causes chronic pain and surface ulceration. Prevention of osteradionecrosis is part of the reason all teeth of questionable prognosis are removed before the start of a course of radiotherapy.

Osteoradionecrosis of the jaw is a significant complication of radiotherapy for oral cavity cancer. In addition to antibiotic medication, treatment options such as hyperbaric oxygen therapy, surgical approaches, and combined therapy with pentoxifylline and tocopherol have been introduced.

Preventive and restorative care are important as well as esthetics as a consideration. This ensures preservation of the patient's vertical face height between their upper and lower teeth when they bite together. The basis of treatment is standard throughout the different types of DI where prevention, preservation of occlusal face height, maintenance of function, and aesthetic needs are priority. Preventive efforts can limit pathology occurring within the pulp, which may render future endodontic procedures less challenging, with better outcomes.

- Challenges are associated with root canal treatment of teeth affected by DI due to pulp chamber and root canal obliteration, or narrowing of such spaces.

- If root canal treatment is indicated, it should be done in a similar way like with any other tooth. Further consideration is given for restoring the root-treated tooth as it has weaker dentine which may not withstand the restoration.

Preservation of occlusal face height may be tackled by use of stainless steel crowns which are advocated for primary teeth where occlusal face height may be hugely compromised due to loss of tooth tissue as a result of attrition, erosion of enamel.

In most cases, full-coverage crowns or veneers (composite/porcelain) are needed for aesthetic appearance, as well as to prevent further attrition. Another treatment option is bonding, putting lighter enamel on the weakened enamel of the teeth and with lots of treatments of this bonding, the teeth appear whiter to the eye, but the teeth on the inside and under that cover are still the same. Due to the weakened condition of the teeth, many common cosmetic procedures such as braces and bridges are inappropriate for patients with Dentinogenesis imperfecta and are likely to cause even more damage than the situation they were intended to correct.

Dental whitening (bleaching) is contraindicated although it has been reported to lighten the color of DI teeth with some success; however, because the discoloration is caused primarily by the underlying yellow-brown dentin, this alone is unlikely to produce normal appearance in cases of significant discoloration.

If there is considerable attrition, overdentures may be prescribed to prevent further attrition of remaining teeth and for preserving the occlusal face height.

If the diver has not been exposed to excessive depth and decompression and presents as DON, there may be a predisposition for the condition. Diving should be restricted to shallow depths. Divers who have suffered from DON are at increased risk of future fracture of a juxta-articular lesion during a dive, and may face complications with future joint replacements. Because of the young age of the population normally affected, little data is available regarding joint replacement complications.

There is the potential for worsening of DON for any diving where there might be a need for decompression, experimental or helium diving. Physically stressful diving should probably be restricted, both in sport diving and work diving due to the possibility of unnecessary stress to the joint. Any diving should be less than 40 feet/12 meters. These risks are affected by the degree of disability and by the type of lesion (juxta-articular or shaft).

Anterior-posterior (AP) and lateral radiographs are typically obtained. In order to rule out other injuries, hip, pelvis, and knee radiographs are also obtained. The hip radiograph is of particular importance, because femoral neck fractures can lead to osteonecrosis of the femoral head.

Condylar resorption is an idiopathic condition, though there are some theories relating to its possible cause. Because condylar resorption is more likely to be in young females, hormonal mediation may be involved. Strain on the temporomandibular joint from orthodontics or orthognathic surgery may be related to the condition. Reactive arthritis, rheumatoid arthritis, and psoriatic arthritis are other possible causes.

The precise frequency of pycnodysostosis has not been determined. Pycnodysostosis can be classified in the large group of genetic diseases that are individually uncommon, but collectively important because of the sum of their numbers, and their heavy impact upon affected individuals.

The diagnosis is a combination of clinical suspicion plus radiological investigation. Children with a SCFE experience a decrease in their range of motion, and are often unable to complete hip flexion or fully rotate the hip inward. 20-50% of SCFE are missed or misdiagnosed on their first presentation to a medical facility. SCFEs may be initially overlooked, because the first symptom is knee pain, referred from the hip. The knee is investigated and found to be normal.

The diagnosis requires x-rays of the pelvis, with anteriorposterior (AP) and frog-leg lateral views. The appearance of the head of the femur in relation to the shaft likens that of a "melting ice cream cone", visible with Klein's line. The severity of the disease can be measured using the Southwick angle.

Children younger than 6 have the best prognosis, since they have time for the dead bone to revascularize and remodel, with a good chance that the femoral head will recover and remain spherical after resolution of the disease. Children who have been diagnosed with Perthes' disease after the age of 10 are at a very high risk of developing osteoarthritis and coxa magna. When an LCP disease diagnosis occurs after age 8, a better outcome results with surgery rather than nonoperative treatments. Shape of femoral head at the time when Legg-Calve Perthes disease heals is the most important determinant of risk for degenerative arthritis; hence, the shape of femoral head and congruence of hip are most useful outcome measures.

Type I: DI associated with Osteogenesis Imperfecta (OI). Type of DI with similar dental abnormalities usually an autosomal dominant trait with variable expressivity but can be recessive if the associated osteogenesis imperfecta is of recessive type.

Type II: DI not associated with OI. Occurs in people without other inherited disorders (i.e. Osteogenesis imperfecta). It is an autosomal dominant trait. A few families with type II have progressive hearing loss in addition to dental abnormalities. Also called hereditary opalescent dentin.

Type III: Brandywine isolate. This type is rare with occurrences only in the secluded populations at Maryland, USA. its predominant characteristic is bell-shaped crowns, especially in the permanent dentition. Unlike Types I and II, it involves teeth with shell-like appearance and multiple pulp exposures.

Mutations in the "DSPP" gene have been identified in people with type II and type III dentinogenesis imperfecta. Type I occurs as part of osteogenesis imperfecta.