Noninfective stomatitis
Non-spccific ulceration can result from trauma or unidentified causcs as in recurrent aphthae. Aetiology Unknown in most cases. Many reported immunological abnormalities, but their aetiological significance is doubtful. This is not an autoimmune disease it affects otherwise healthy persons, and is not associated with recognized autoimmune diseases. There are no useful immunological diagnostic tests and there is no reliable response to immunosuppressive treatment. In 5-10 of cases, ulcers arc...
Keratoses leukoplakias white lesions
leukoplakias are chronic white kcratotic mucosal plaques which are not due to any identifiable disease. The term is purely clinical and has no histological implications, but histology' is necessary to cxcludc malignancy or other diseases. Most leukoplakias arc not premalignant but red lesions erythroplasias pp. 95 96 are frequently precancerous or invasive carcinoma. Terminology Oral white plaques share many histological features, and idiopathic forms are often not distinguishable...
Ossifying cementifying fibroma
Typically seen in the mid-30s age group, women being twice as frequently affected as men. The mandible is usually affected. The clinical and radiographic features of ossifying fibroma are the same as for cementifying fibroma and it is not a separate entity. It has a similar self-limiting course. The tumour typically shows bony trabcculac Fig. 104 but usually there arc also or predominantly cementicle-like concretions in fibrous stroma Fig. 103, p. 52 . It produces a circumscribcd, rounded area...
Osteoma
May be endosteal or more often periosteal but then it is often difficult to distinguish from exostoses. Compact osteoma lamellae of dense compact bone with relatively few osieocytes Fig. 106 . Cancellous osteoma widely spaced bony trabeculae with cortex of lamcllatcd bone Fig. 107 . fig. 106 Compact osteoma. fig 107 Cancellous osteoma.
Osteosarcoma
The most common primary tumour of bone. It is a rare complication of radiotherapy or Paget's disease of the axial skeleton. Osteosarcoma usually affects young persons, particularly males. Microscopy Appearances are variable and the tumour is either predominantly osteolytic undifferentiated or productive, and then may be predominantly osteochondroblastic or fibroblastic. It consists of abnormal tumour osteoblasts, which are typically angular, hyperchromatic and larger than normal often in large...
Nonneoplastic bone diseases
This is a nonspecific term encompassing diseases ranging from fibrous dysplasia to the well-circumscribed lesions of ossifying fibroma and uncommon, apparently intermediate, types. It is a controversial area, with diagnosis dependent on consideration of clinical and radiographic features, microscopy and behaviour. Typically seen in young adults of either sex as rounded, painless, smooth bony swelling of the maxilla. The swelling may disturb function or occlusion. Radiography shows a rounded...
Squamous odontogenic tumour
Rare tumour consisting of multiple islands of well-differentiated squamous cells in connective tissue stroma Figs 94 amp 95 . It has a wide age distribution and no apparent sex or site predilection. There is probably minimal risk of recurrence if the tumour is conservatively excised. fig. 94 Squamous odontogenic tumour. fig. 95 Squamous odontogenic tumour. High power. fig. 94 Squamous odontogenic tumour. fig. 93 Ameloblastic fibroma. High power. fig. 95 Squamous odontogenic tumour. High power.
Cementomas and cemental dysplasias
The tumour usually affects males under 25 years. It appears as a radiopaque apical mass with radiolucent margin, usually in the molar region. Microscopy A rounded or irregular mass of ccmcntum can be seen on the root of the tooth Figs 100 amp 101 . The ccmcntum is in a pagetoid 'mosaic' pattern with many ccmcntoblasts Fig. 102 , a peripheral zone of pericementum and a zone of uncalcified cement matrix precementum and fibrous pericementum. Cementifying ossifying fibroma Most often found in the...
Odontomas
Most are malformations of developing dental tissues hamartomas . Occasionally, an odontoma is associated with a tumour such as ameloblastic fibroma. Compound type multiple small tooth-like structures denticles within fibrous follicles Fig. 98 . Complex type completely irregular mass of dental tissues Fig. 99 . It may have a cauliflower form with dental tissues surrounding a much branched pulp chamber. Though lacking any morphological resemblance to a tooth, complex odontomas have the individual...
Cysts without epithelial lining nonodontogenic pseudocysts
Solitary bone cyst Incidence and Rare, but with peak age incidcncc in the second aetiology dccade. The aetiology is speculative. Such cysts were traditionally thought to be traumatic earlier terms haemorrhagic or traumatic bone cyst , but there is no supporting evidence. Pathology Almost invariably in mandible. The cavity- and radiolucency extend through cancellous bone and arch up between the roots of teeth but rarely expand the bone. The cyst may contain scrosanguinous fluid or be empty...
Odontogenic keratocyst
Aetiology Unknown. Presumably the cyst originates from primordial odontogenic epithelium any part of dental lamina or remnants thereof or enamel organ before the start of amelogenesis. A tooth is sometimes missing. Incidence About 10 of odontogenic cysts. The male to female ratio is about 1.5 to 1. They form most frequently in young adults or at age 50-60 possibly then as a result of slow growth and late detection. Pathology About 75 in body or ramus of mandible. Typically, infiltrative growth...
Odontogenic myxoma
Probably arises from the mesenchymal component of tooth germ. The tumour is usually detected in the second or third decade, slightly more frequently in the mandible, as a cyst-like or soap bubble area of radiolucency with expansion of bone Fig. 96 . Microscopy I.oose, mucoid fibrillary tissue contains spindle or stellate cells with long, delicate, intertwining processes and, rarely, rests of odontogenic epithelium scattered throughout the tumour. Sometimes there is extensive bone invasion Fig....
Gingival swelling
Microscopy Exaggerated response to plaque, with gross infiltration of gingivae by lcukacmic cells, gingival swelling, and accelerated periodontal destruction Fig. 46 . Hereditary type generalized smooth gingival swelling may overgrow and conceal erupting teeth. Drug'dssociaied hyperplasia produces bulbous swellings of interdental papillae. Causes includc phenytoin, cyclosporin, nifedipine and its analogues calcium channel blockers . Both show hyperplasia of gingival collagcn with 'stretching'...
Periodontal radicular cysts
Aetiology Pulp death, apical periodontitis, proliferation of epithelial rests of Malassez, cystic change in epithelium expansion of cyst by hydrostatic pressure resorption of surrounding bone. Incidence 65-75 of jaw cysts. Periodontal cysts are the most common cause of chronic swellings of the jaws. chronic inflammatory infiltrate bony shell undergoing progressive resorption. The epithelial lining is stratified squamous in type and very variable in thickness sometimes with arcadcd configuration...
Melanotic neuroectodermal jaw tumour of infancy progonoma
This is a rare tumour that is not odontogenic but originates from the neural crest. It is usually detected as a ragged area of radioluccncy in the maxilla at about 3 months the mandible or other sites are rarely affected. Microscopy Consists of a connective tissue stroma containing foci of pigmented melanin-containing cells Fig. 90 with pale nuclei, surrounding small spaces or clefts, together with groups of non-pigmcnted cells, alone or surrounded by-pigment cells Fig. 91 . There is a variable...
Ameloblastoma contd
Behaviour Biopsy is essential, particularly for cystic ameloblastomas where a recognizable tumour may be present only as a limited area of mural thickening. Differentiation from non-ncoplastic cysts or other radiolucent lesions by radiography alone is unreliable. Ameloblastomas are invasive and recur unless widely excised. Their behaviour is not determined by histological pattern but the granular cell type is possibly more likely to recur. The monolocular, unicystic variant may respond to...
Cysts within tumours
Cysts within tumours can be mistaken for simple cysts clinically and radiographically but their precise nature is confirmed by microscopy. They arc most common in ameloblastoma Fig. 69 . A calcifying odontogenic cyst can be a cyst or a solid tumour. Microscopy Extensive cystic changc see p. 42 can overgrow the tumour. The lining bccomcs flattened and may be indistinguishable in part from that of a simple cyst. Elsewhere, ameloblastoma cclls arc more obvious in the cyst lining and a typical...
Developmental defects of teeth
Amelogenesis imperfecta hypoplastic or hypocalcificd types Dentinogenesis imperfecta. Acquired Severe metabolic disturbances hypoplastic type defective matrix formation enamel irregular, overall thin, sometimes nodular or pitted but well-calcified, hard and translucent Fig. 1 . hypocalcified type normal matrix formation and morphology but soft and chalky, and readily chipped away. Dentinogenesis imperfecta mantle superficial dentine with regular tubules remainder a few irregular tubules,...
Dentigerous cysts
Aetiology Cystic change in remains of enamel organ alter completion of enamel formation. This is a developmental dcfcct of unknown causc. Incidence 15-18 of jaw cysts. The male to female ratio is more than 2 to 1. Microscopy The cyst wall is attached to the neck of the tooth at or near the amclocemental junction Figs 57 amp 58 . The lining of the cyst probably originating from external enamel epithelium typically appears as a thin flat layer of squamous cells without a defined layer of basal...
Calcifying epithelial odontogenic Pindborg tumour CEOT
This is a rare but important tumour because of its resemblance to and risk of confusion with poorly-differentiated carcinoma. Age and site distribution arc similar to that of ameloblastoma. Radiographic appearances are variable there may be circumscribed or diffuse radioluccncy often with scattered snow-shower opacities. Trabcculation is also variable multilocular, honeycomb or monolocular appearances may be seen. Microscopy Sheets of variable-sized squamous cells, typically with well-defined...
Calcifying odontogenic cyst
Though often cystic, this lesion can also be solid and may be a benign odontogenic tumour. Incidence Rare. Any age can be affcctcd but the lesion is most often detected in the second decade. Microscopy Fibrous wall with lining predominantly of squamous epithelium but the basal layer may be columnar and ameloblast-like. Abnormal kcratinization of spinous cclls produces ghost cclls consisting of distended eosinophilic epithelial cclls either anuclcar or occasionally containing nuclear remnants...
Ameloblastoma
Most common neoplasm of jaws. It mainly affects males aged over 40 years, with about 80 of tumours being seen in the ramus or posterior body of the mandible. Ameloblastoma typically appears as a multilocular cyst on a radiograph occasionally it is monolocular and can mimic a periodontal or dentigcrous cyst. It is slow growing and locally invasive but does not metastasize ameloblastic carcinoma is exceedingly rare. Microscopy Several subtypes are recognizcd. Appearances may also vary within an...
Periodontal radicular cysts contd
Microscopy Cholesterol from the breakdown of blood cells is frequently seen in cysts as needle-shaped clefts. Clefts typically form in the cyst wall but extend into the cyst cavity Figs 53 and 58 . Clefts are surrounded by giant cells whose cytoplasm becomes stretched and attenuated, but the clusters of nuclei may be seen near one end Fig. 54 . Aspiration of cyst fluid typically also shows cholesterol as flat, rhomboid, notched crystals Fig. 55 often with many inflammatory' cells. Microscopy...
Nasolabial cyst
Aetiology Unknown. This is an exceedingly rare soft tissue cyst external to the alveolar ridge beneath the ala nasi. It probably arises from remnants of the lower end of the nasolacrimal duct. A nasolabial cyst may be seen ai almost any age but the peak incidence is at 40-50 years. Microscopy The lining classically but often not is of non-ciliaied columnar epithelium but may be squamous or ciliated with a fibrous wall Fig. 68 . Rg. 65 Daughter cysts in Iceratocyst wall. Rg. 65 Daughter cysts in...
Periodontal lateral abscess
Aetiolo amp Usually a complication of advanced periodontitis. It may be due to injury to the pocket floor food-packing or more virulent infection. Pathology Rapid acceleration of periodontal destruction. Destruction of epithelial pocket lining. Dense neutrophil infiltrate and suppuration Fig. 43 . Widespread osteoclastic resorption of bone Fig. 44 increasing width and depth of pocket to form deep intrabony pocket. Pus may exude from pocket mouth or point on attached gingiva. Fig 41 Late...
Chronic periodontitis
Aetiology Pcrsistcncc of bactcrial plaque. Progression of inflammation with tissue destruction is a common but not invariable sequel to chronic gingivitis there is wide individual variation for unknown reasons. Microbiology Many potent pathogens e.g. Porphyromonas species, and immunobgy capnocytophaga, Clostridia, fusobacteria, etc. can be isolated from periodontal pockets, but individual roles in tissue destruction are uncertain. Some e.g. Actinomyces species produce bone resorbing factors. A...
Periodontal disease
Normal periodontal tissues. Gingival epithelium comprises oral epithelium extends from mucogingival junction to crest of gingival margin and has rete ridges sulcular epithelium joins the oral and junctional cpithclia junctional epithelium tends to be flattened and forms a union with the tooth in the epithelial attachment extending to the amclodcntinal junction in normal mature tissue, deep to which is the periodontal ligament. Connective tissue gingival fibres support the gingival margin as a...
Chronic gingivitis
Aetiology Inflammatory' response to bacterial plaque accumulating at the gingival margin. The bacterial population is mixed with no specific pathogens identified although, initially, bactcria arc Gram-positive and aerobic. An increasing bulk of plaque 100-300 cells thick is associated with increasing prominence of Gram-negative bacteria, such as vcilloncllac, fusobacteria and Campylobacter. The process is probably initiated by leakage of bacterial antigens from plaque in the gingival sulcus....
Apical periodontitis
Aetiology Secondary lo carics and pulp necrosis in most eases. Trauma lo tooth severing apical vessels. Root canal treatment irritant medicaments or overextension . Pathology Acute accumulation of acute inflammatory cells neutrophils and fluid exudate in potential space between apex and periapical bone Fig. 21 . If neglected, there is suppuration and resorption, usually of buccal plate of bone, and sinus formation on the gum overlying the apex of the tooth. In deciduous molars, inflammation,...
Hypercementosis
Chronic apical periodontitis adjacent to resorption . Buried teeth, Pagct's disease. Pathology Usually lamellar sequential deposition of layers of cementum forming smooth thickcning of root. Rarely Pagct's disease or ccmcntoblastoma , there is an irregular jigsaw-puzzle 'mosaic' pattern of intermittent deposition and resorption Fig. 28 . fig. 25 Internal resorption of dentine. fig. 26 External resorption. fig. 25 Internal resorption of dentine. fig. 26 External resorption. fig 28...
Closed pulpitis
Typical inflammatory reactions are initially localized to a minute area Fig. 13 but typically lead to necrosis of pulp due to restriction of blood supply by the apical foramen, compression of vessels by oedema in the confined space and thromboses. Pathology All degrees of severity may be encountered, namely acute hyperaemia and oedema Fig. 14 progressive infiltration by neutrophils destruction of specialized pulp cells abscess formation Fig. 15 There is little correlation between symptoms and...
Enamel caries
Pathology Pre-cavitation stage submicroscopic bacterial acid leads to production of increasing size and numbers of submicroscopic pores in enamel. Light microscopy shows conical area of change with apex deeply Fig. 6 , comprising dense surface zone more radiopaque with enhanced striae of Retzius peripheral translucent zone. Degrees of demoralization in different zones are assessed by polarized light studies and microradiography. Progressive demoralization eventually allows entry to bacteria....
Pathology
Emeritus Professor of Oral Medicine and Pathology, University of London, UK Visiting Professor, Baylor University Medical Center and Dental College, Dallas, Texas, USA Lecturer in Oral Medicine and Pathology, United Medical and Dental Schools of Guy's and St Thomas's Hospitals, University of London, UK EDINBURGH LONDON MADRID MELBOURNE NEW YORK AND TOKYO 1993 Medical Division of Pearson Profession I imiicd Distributed in the United States ol America by Churchill Livingstone Inc., 650 Avenue ol...