Article
Specialist referral may be indicated if the Practitioner feels:
Disorders in the jaws
Many diseases of, or in, the jaws present asymptomatically, as radiolucencies, radio-opacities or with mixed appearances on radiographs. Other presentations are as swellings, pain or sometimes fracture or disturbance of tooth eruption (displaced, missing or loose teeth). Swellings that appear to originate from the jaws may arise from subcutaneous tissues or bones. The mnemonic MINT aids diagnosis: Malformations, eg tori and fibro-osseous lesions.
Inflammatory conditions, eg odontogenic infections, osteomyelitis, actinomycosis, tuberculosis, or syphilis.
Neoplasms and cysts (see below).
Trauma causing subperiosteal haematomas.
Investigations largely involve imaging, and serum calcium, phosphate, and alkaline phosphatase levels but histopathology is almost invariably required.
Pseudo-diseases
Some jaw conditions are ‘pseudo-diseases’, including: unerupted teeth, tori (Figures 1–3), bone marrow defects, traumatic bone cyst, Stafne bone defect (static bone cyst), osteosclerosis, pseudocyst of maxillary sinus, or sub-pontic osseous hyperplasia.
A number of bone diseases may also affect the jaws.
Non-neoplastic diseases
Neoplastic disorders
| Benign | Malignant |
|---|---|
| Chondroma | Chrondrosarcoma |
| Osteoblastoma | Osteosarcoma |
| Osteochondroma | |
| Osteoma |
Fibro-osseous lesions
Fibro-osseous lesions are a group of conditions characterized by replacement of normal bone by a proliferating fibrous stroma which forms varying amounts of woven bone spicules and cementum-like material (Table 2).
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Cemento-osseous dysplasia
Cemento-osseous dysplasia (COD), periapical cemental or cemento-osseous dysplasia (PCD) or cementoma is an older term)
Cemento-osseous dysplasia is a fibro-osseous lesion common in black females during fourth and fifth decades, presenting with radiolucent and radio-opaque lesions at the apices of vital teeth (periapical type), which may be isolated (focal) or multi-quadrant (florid) (Figure 4). Lesions usually involve the mandibular anterior teeth, start as well-circumscribed radiolucent lesions and progressively become radio-opaque centrally, although a thin radiolucent margin is usually visible (helpful in distinguishing from enostosis [idiopathic osteosclerosis]). The lesions are asymptomatic, usually incidental radiographic findings, and the related teeth are vital. Florid COD is probably a widespread form, also occurring mainly in black females but usually affecting three or four quadrants. Bone expansion may occur, and the lesions may present with pain. Bone cysts may develop, and there is a liability to osteomyelitis. Sometimes COD occurs as isolated lesions unassociated with teeth (focal cemento-osseous dysplasia).
COD is self-limiting, so treatment is best limited to symptomatic relief of active infection and localized sequestration. In some cases of florid COD, surgical removal may be required.
Cherubism
The name for this comes from the appearance of angelic putti (chubby boys) in Renaissance art, misnamed by some as cherubs. The mandible in particular is replaced with excessive fibrous tissue which usually resolves as the child matures. Rarely it causes premature loss of primary and uneruption of permanent teeth. Though sometimes named familial fibrous dysplasia of the jaws, cherubism is an autosomal dominant condition involving the SH3BP2 gene and has little in common with fibrous dysplasia.
Fibrous dysplasia
Fibrous dysplasia (FD) is a self-limiting, fibro-osseous lesion caused by mutation in the gene encoding G protein (GNAS1). FD usually affects only one bone (monostotic: about 70%) but occasionally several bones (polyostotic). Maxillofacial fibrous dysplasia may occur anywhere in the jaws but is essentially monostotic and typically affects the maxilla in young people, although it sometimes affects adjacent bones (craniofacial fibrous dysplasia), but rarely crosses the midline. CT can best assess the extent in the facial skeleton.
McCune-Albright's syndrome is FD bone lesions with skin pigmentation and endocrinopathy (precocious puberty in females and hyperthyroidism in males).
Bone enlarges in FD but the morphology is preserved, distinguishing FD from a neoplasm. FD lesions vary from radiolucent to radio-opaque, often a ‘ground-glass appearance’ (Figure 5) with ill-defined margins – a feature helpful to distinguish it from other lesions. Typically, no treatment is needed. Bisphosphonates can help and surgery may be indicated if there is major deformity or pressure on nerves.
Hypercementosis
Hypercementosis is increased deposition of cementum on roots, caused by local trauma, inflammation, Paget's disease, or may occur idiopathically.
Ossifying fibroma (Cemento-ossifying fibroma)
Ossifying fibroma is a usually benign, slow-growing, painless bone neoplasm, typically monostotic and seen in the third and fourth decades in the posterior mandible as a radiolucent, radio-opaque, or mixed opacity and which has a fibro-osseous microscopic appearance. Ossifying fibroma and focal COD are not easily differentiated histopathologically. Juvenile ossifying fibroma is an aggressive variant with a rapid growth pattern seen mainly in boys aged under 15 years.
Traditionally, the initial treatment has been simple curettage. More definitive resection has been reserved for recurrent disease.
Paget's disease of bone
Paget's disease of bone (PDB) is a progressive fibro-osseous disease affecting bone and cementum, characterized by disorganization of osteoclastogenesis (osteoclast formation) – a process dependent on two cytokines, macrophage colony stimulating factor (M-CSF) and receptor activator of nuclear factor kappa-B ligand (RANKL), which induce gene expression changes, presumably by inducing transcription factors. The tumour necrosis factor (TNF) receptor superfamily activate nuclear factor kappa-B (NF-κB), and RANK (for receptor activator of NF-kappa B), which is involved in osteoclastogenesis.
Seen mainly in males over 55 years of age, there is a strong genetic component; 15–20% have a first-degree relative with PDB. Genes involved include the sequestosome1 gene (SQSTM1).
In PDB, bone remodelling is disrupted, and an anarchic alternation of bone resorption and apposition results in mosaic-like ‘reversal lines’. Most patients are asymptomatic. A minority of patients with Paget's disease experience a variety of symptoms, including bone pain secondary osteoarthritis, bone deformity and neurological complications due to compression of nerves.
In early lesions, bone destruction predominates (osteolytic stage) and there is bowing of the long bones, especially the tibia, pathological fractures, broadening/flattening of the chest and spinal deformity. The increased bone vascularity can lead to high output cardiac failure.
Later, as disease activity declines, bone apposition increases (osteosclerotic stage) and bones enlarge, with progressive thickening (between these phases is a mixed phase). PDB is typically polyostotic and may affect skull, skull base, sphenoid, orbital and frontal bones. The maxilla often enlarges, particularly in the molar region, with widening of the alveolar ridge. In early lesions, large irregular areas of relative radiolucency (osteoporosis circumscripta) are seen, but later there is increased radio-opacity, with appearance of ‘cotton wool’ pattern. Constriction of skull foramina may cause cranial neuropathies. The dense bone and hypercementosis makes tooth extraction difficult, and there is also a liability to haemorrhage and infection.
Diagnosis supported by imaging, biochemistry and histopathology. Bone scintiscanning shows localized areas of high uptake. Plasma alkaline phosphatase and urine hydroxyproline levels increase with little or no changes in serum calcium or phosphate levels. Bisphosphonates are used in the treatment of PDB but calcitonin may also help.