Metallothionein in human gingival amalgam tattoos.

Amalgam tattoos occur when small particles of dental amalgam, composed largely of silver (Ag) and mercury (Hg), are inadvertently implanted into oral soft tissues during dental procedures. Metallothioneins (MTs) are ubiquitous, low molecular weight, cysteine-rich, metal-binding proteins that are inducible by many agents including metals and may be involved in the detoxification of toxic metals such as Hg. In this study, the correlation between MT expression and amalgam tattoos in human gingiva was investigated using energy-dispersive X-ray microanalysis (EDX) and immunohistochemical techniques. Light microscopically, amalgam tattoos presented as either fine granular particles or larger discrete opaque globular particles in connective tissues. EDX revealed the smaller particles to be silver sulphide (Ag(2)S), while the larger particles exhibited a shell of Ag(2)S that contained irregularly distributed masses of Ag and Hg. Particles of tin (Sn) were also found. No MT staining was observed in collagen, fibroblasts or blood vessels in areas exhibiting abundant amounts of embedded fine granular Ag(2)S particles. Blood vessels exhibiting relatively few amalgam particles stained positively for MT. Cells with the morphological features of histiocytes located directly adjacent to larger pieces of amalgam showed intense MT staining. These results indicate that amalgam tattoos contain no Hg or free Ag except in large globular pieces of amalgam, which still contain Hg and which induce MT expression in adjacent histiocytes. This suggests that Hg leaching from impacted dental amalgam particles induces MT, while residual Ag(2)S and Sn particles do not. MT may therefore act to reduce Hg exposure in patients with amalgam tattoos.

Idiopathic noncondylar hemimandibular hyperplasia.

A female patient with 'idiopathic non-condylar hemimandibular hyperplasia' was followed from the age of 7.5-11.5 years. This rare disorder was characterised by an increase in volume of the right inferior ramus and mandibular body. It also included accelerated development and eruption of the teeth on the affected side, but no indication of enlargement of the condyle or the condylar neck. To date, review of the literature revealed several cases of hemimandibular hyperplasia and unilateral condylar hyperplasia, both of which present with enlargement of the condyle. However, the patient differed significantly from any previously reported cases, since she had no enlargement of the condyle. The above mentioned patient also differed from patients with hemihypertrophy, since the teeth were accelerated in development, but not hyperplastic. In addition, from histopathologic and radiographic examinations, as well as an angiogram, benign fibro-osseous and vascular lesions of the mandible were excluded. Although this is a single case report and neither the aetiology nor the pathogenesis is yet understood, it may suggest a new disorder of the mandible. Therefore, future reporting of similar cases should be encouraged.

Immunohistochemical localization of fibroblast growth factors FGF-1 and FGF-2, and receptors FGFR2 and FGFR3 in the epithelium of human odontogenic cysts and tumors.

Acidic (FGF-1) and basic (FGF-2) fibroblast growth factors are members of a family of growth factors that function in growth, differentiation and regeneration of a variety of tissues. Their presence in human odontogenic cysts and tumors has not been previously investigated. This study was designed to detect immunohistochemically the presence of these factors and two fibroblast growth factor receptors (FGFR2 and FGFR3) in a cross section of odontogenic cysts and tumors, to determine if they may be involved in the differentiation of odontogenic epithelium or, more specifically, in the development of particular cysts or tumors. Archival formalin-fixed paraffin-embedded tissues were used. With some exceptions, FGF-2 and the receptor FGFR2, were found in the cytoplasm and occasionally in the nuclei of cells of odontogenic epithelium, while FGF-1 and the receptor FGFR3, were absent or only focally or weakly detected, using standard immunohistochemical techniques. The data are similar to those published for normal murine odontogenesis, suggesting that these factors are associated with odontogenic differentiation rather than pathogenesis. The presence of significant nuclear staining in odontogenic epithelium associated with embryonic mesenchyme in ameloblastic fibromas and ameloblastic fibro-odontomas suggests that FGF-2 may be involved in directing nuclear activity at the histodifferentiation stage of odontogenesis.

Oral bowenoid lesions: differential diagnosis and pathogenetic insights.

OBJECTIVE: To determine if oral lesions exhibiting bowenoid features reflect the diverse microscopic appearance and biologic behaviour of Bowen's disease and bowenoid papulosis of the skin and genitalia. STUDY DESIGN: Seven cases of oral bowenoid lesions (6 with follow-up data) were assessed for differences in histologic features, human papillomavirus (HPV) viral status, and selected immunohistochemically detectable cell cycling proteins (p53, WAF-1, Cyclin D1, Bcl-2) and were correlated with available follow-up data. RESULTS: Two histologic subsets were identified. One, which was believed to correspond to Bowen's disease, exhibited large numbers of transepithelial apoptotic bodies, dyskeratotic cells and mitoses (bowenoid elements), poor differentiation of background epithelial cells, and consistent HPV-16/18 positivity. The other, believed to correspond to bowenoid papulosis, exhibited few bowenoid elements, good background differentiation, and inconsistent HPV-16/18 positivity. One of the aggressive cases exhibited repeated recurrences despite apparent total clinical excision, whereas none of the other group recurred. CONCLUSION: Although a small number of cases are in this study, results suggest that oral bowenoid lesions may exhibit histopathologic and behavioral variations ranging from oral Bowen's disease to oral bowenoid papulosis. Studies on more cases are needed to confirm this initial impression.

Immunohistochemical localization of metallothionein in the developing teeth of cadmium-injected rats.

The ability of cadmium (Cd) to induce the synthesis of metallothionein (MT) in the developing teeth of the rat was investigated. Rats were given daily intraperitoneal injections of cadmium chloride (1.5 mg Cd/kg) for 7 days. The induction of MT synthesis in incisor teeth after Cd treatment was investigated immunohistochemically using a polyclonal antibody to MT. Immunoreactivity to MT was observed in the papillary layer of epithelial cells of the secretory zone, in one layer of epithelial cells of the presecretory zone and within ameloblasts of the postsecretory zone. Normal control rats did not exhibit MT staining. These results indicate that Cd induces MT synthesis within specific epithelial cells of the enamel organ of the rat. It is proposed that these findings demonstrate an adaptive cellular mechanism that protects these cells from cadmium toxicity.

Caliber-persistent labial artery. A common vascular anomaly.

Sixteen cases of caliber-persistent labial artery of the lips have been reported to date in the English literature. Six of these were clinically misdiagnosed as squamous cell carcinoma and treated with wedge resection. To date, we have seen 187 cases clinically and an additional 23 cases through our surgical oral pathology services. Careful clinical observation usually reveals a soft linear or papular bluish elevation above the labial mucosal surface. The unique feature is pulsation--not simply pulsation toward and away from the observer, which can be caused by an underlying artery, but lateral pulsation, which only an artery can exhibit. All but 2 of our 187 clinical cases were asymptomatic. To the best of our knowledge, this is the first report of caliber-persistent labial artery of the upper lip. The upper:lower lip ratio for the clinical cases was almost 2:1. Three times as many lower lip as upper lip lesions were biopsied. Males and females were almost equally affected (clinical cases, 76:86; histopathologic cases, 9:13). Although a vascular term (artery, hemangioma, phlebolith, varix, vascular malformation) was used on the biopsy form in one half of the clinical differential diagnoses, none of the clinical histories mentioned pulsation. In contrast to the cases of Miko et al. in 1980 and 1983, none of our cases manifested itself as an ulcer, nor was carcinoma ever mentioned in the clinical differential diagnosis. The purpose of this article is to familiarize clinicians and pathologists with the clinical and histopathologic features of this seldom reported but common vascular anomaly. Clinicians should carefully look for lateral pulsation in lip mucosal papules so as to avoid unnecessary surgery and intraoperative arterial bleeding. Pathologists should recognize that a relatively large-caliber superficial artery in a lip biopsy may not be an incidental finding but rather the clinical lesion that was biopsied.

Lateral periodontal cyst: a case report and review of the literature.

A polycystic lateral periodontal cyst was observed over a period of 25 months. The case history, a description of the natural history of this lesion and its diagnostic characteristics, and a review of the literature are presented.

New developments in selected cysts of the jaws.

The number and variety of cysts that occur in the jaws are greater than those in any other part of the body. Consequently, dental practitioners must keep up with advances in this field, including the definition of new entities, such as the glandular odontogenic cyst; the deletion of the old incorrect concept of maxillofacial fissural cysts, including the globulo-maxillary cyst; and the advances in the molecular biology of established cysts, such as the dentigerous cyst and the odontogenic keratocyst.

Common salivary gland disorders: an update.

Disorders of the salivary glands range from common inflammatory and functional conditions, to rare types of neoplasms. An overview and update of selected, common non-neoplastic and neoplastic conditions is presented.

Atypical cartilage in reactive osteocartilagenous metaplasia of the traumatized edentulous mandibular ridge.

Eighteen cases of reactive osteocartilagenous metaplasia of the edentulous mandibular alveolar ridge forming clinical masses that mimic neoplasms are reported. Although most of these lesions appeared histologically benign, three exhibited atypical microscopic features suggestive of chondrosarcoma. Of those cases that were followed, none of the lesions recurred after simple surgical excision. Because many investigators consider all cartilagenous lesions of the jaws potentially malignant, the importance of recognizing this benign condition is stressed.

Osteopathia striata, short stature, cataracts, and microdontia: a new syndrome? A case report.

A case of osteopathia striata, childhood cataracts, short stature, elbow deformity, and microdontia with rhizomicry in a white male is reported. The report includes a detailed analysis of dental changes. The relationship of this syndrome to other similar conditions including osteopathia striata with cranial base sclerosis and Rothmund-Thomson syndrome are discussed.

Salivary gland duct involvement in oral epithelial dysplasia and squamous cell carcinoma.

The clinical implications and prognostic significance of oral dysplastic or cancerous epithelium involving salivary gland ducts have not been previously investigated. Screened routine tissue sections of 1216 cases of oral epithelial dysplasias and squamous cell carcinomas revealed 26 examples (2.14%) that exhibited unequivocal ductal involvement. Ductal involvement was more likely to occur in floor of mouth lesions and in lesions exhibiting severe dysplasia or carcinoma in situ. Clinical follow-up on 23 cases showed that the recurrence rate of the preinvasive lesions that exhibited ductal involvement was equal to that of the squamous cell carcinomas. The depth of ductal dysplasia did not correlate with recurrence rate. These results suggest that the involvement of salivary gland ducts by oral epithelial dysplasias and carcinomas in situ is an uncommon but significant finding. Surgical stripping or ablation of such lesions should extend at least 3 mm below the surface to ensure eradication of these reservoirs of dysplastic cells.

The small dentigerous cyst. A diagnostic dilemma.

The dentigerous (follicular) cyst is recognized as one of the most common lesions of the jaws. Clinical, radiographic, histologic, and prognostic characteristics are well established for medium to large pericoronal cysts that are lined by nonkeratinized stratified squamous epithelium. However, it can be difficult, if not impossible, to distinguish between a small dentigerous cyst and a large dental follicle despite the availability of both radiographic and histologic information. Epidemiologic data derived from a comparative study of 1662 dentigerous cysts and 824 dental follicles showed considerable overlap in age distribution and site predilection and were therefore of minimal use in reaching a final diagnosis. At present, it appears that identifying a cystic cavity at the time of surgery may be the only reliable way to arrive at a definitive diagnosis when radiographic and histologic features are insufficient to distinguish between a small dentigerous cyst and a large dental follicle.

Peripheral odontogenic fibroma.

The peripheral odontogenic fibroma is characterized by a fibrous or fibromyxomatous proliferation that contains varying amounts of odontogenic or presumed odontogenic epithelium. It has been considered a rare gingival neoplasm that, because of a lack of follow-up information in most reported cases, has had an unknown biologic behavior. Clinical data from this study indicate that the lesion is more common than previously reported and that it has a significant recurrence rate. Light and electron microscopic data reveal a relatively broad spectrum of epithelial and mesenchymal components, including a rare granular cell type. Because the presence of both epithelial and mesenchymal elements are required for its diagnosis, the lesion is logically classified as a mixed epithelial/mesenchymal odontogenic tumor, rather than a purely mesenchymal tumor.

Peripheral odontogenic keratocyst.

The gingival cyst of the adult exhibits an epithelial lining that is essentially the same as the lateral periodontal cyst. Although the gingival cyst of the adult exhibits some morphologic variability, its lining is generally considered to be nonkeratinized. Nonetheless, rare cases of gingival cyst of the adult that exhibit a keratinized epithelial lining have been reported in the literature. There is now a growing tendency to consider this variant as a separate entity. This article describes six cases of gingival cysts that exhibit the histologic features of the odontogenic keratocyst. Evidence from this series suggests that the biologic behavior of this subset of gingival cysts is different from that of the generic gingival cyst of the adult and that the term peripheral odontogenic keratocyst more accurately describes this entity.

Relative incidence of odontogenic tumors and oral and jaw cysts in a Canadian population.

The diagnoses of 40,000 consecutively accessioned oral biopsies from the Oral Pathology Diagnostic Service, University of Western Ontario, London, Canada, were reviewed. All odontogenic neoplasm, neoplasm-like lesions (tumors), and true cysts of the oral tissues and jaws were listed. Clinical data were reviewed, and microscopic diagnoses were confirmed for cases in which diagnoses were ambiguous. Records of all cases were examined to identify distant referrals that were not representative of the study population. Of a total of 445 (1.11%) odontogenic tumors, 392 (0.98%) were lesions from patients in the usual local drawing area of the biopsy service; 53 were referred from distant centers. From the local population, odontomas were by far the most common tumor (51.53%) followed by ameloblastomas (13.52%) and peripheral odontogenic fibromas (8.93%). Locally, radicular (periapical) cysts were the most common odontogenic cyst (65.15%) followed by the dentigerous cyst (24.08%) and the odontogenic keratocyst (4.88%). The most common nonodontogenic cyst was the nasopalatine duct cyst that accounted for 73.43% of this subset of cysts. Surprisingly few studies of this type are available, especially for odontogenic tumors. These data are important to assess geographic differences in the incidence of lesions and to allow clinicians to make realistic judgments in counseling patients before biopsy about the probability of diagnosis and risks associated with nonspecific clinical or radiographic lesions.

Lingual mandibular sequestration and ulceration.

This study analyzed 11 patients who had small sequestra associated with ulceration of the lingual mucosa in the posterior mandibular molar area at the level of the mylohyoid ridge. The patients were adults (mean age, 45.3 years) with complaints of sensitive, occasionally painful lesions that appeared for periods that ranged from 1 week to several months. No abnormalities were evident on periapical radiographs; however, in three cases in which occlusal radiographs were available, small irregular radiopacities contiguous with the cortex were noted. Spontaneous exfoliation or surgical removal of the sequestrum resulted in resolution of the lesion. The possible etiologic factors associated with this apparent clinical-pathologic entity are discussed.