Intraneural and perineural epithelial structures.

The fact that numerous embryologic epithelial remnants are a normal occurrence in the oral region is well known. That some of these epithelial remnants occur within peripheral nerves is less well known. This study presents examples of intraneural epithelial rests from 3 different anatomic sites: the soft tissues of the jaws (a juxtaoral organ of Chievitz), the posterior maxilla (an ondotogenic rest), and the anterior maxilla (a nasopalatine duct remnant). The purpose of this paper is to draw the attention of surgical pathologists to this phenomenon in the head and neck in order to avoid extensive unnecessary surgery.

Heterotopic gastric cyst of the oral cavity.

The heterotopic gastric cyst of the oral cavity is a rare lesion. A recurrent gastric cyst in the floor of the mouth of a young female patient is presented. Current theories dealing with the histogenesis of these lesions are presented and discussed. Based on the available embryologic and clinical information, a new histogenetic concept for the development of the heterotopic gastric cyst is proposed.

Cyclosporine therapy. Its significance to the periodontist.

Cyclosporine is a relatively new immunosuppressive agent which has been used successfully to prevent organ transplant rejection, to treat type-I diabetes mellitus as well as several other autoimmune disorders. It is anticipated that the therapeutic use of cyclosporine will progressively increase in the future to include the treatment of numerous other disorders. As its clinical use broadens, more health professionals will need to become familiar with the beneficial effects as well as some of the undesirable side-effects of cyclosporine therapy. Two side-effects of the drug which are of interest to the periodontist are gingival hyperplasia and transient perioral hyperaesthesia. It is anticipated that the dental profession, particularly periodontists, will be called upon to help prevent, control or treat these side effects. The purpose of this paper is to familiarize the periodontist with cyclosporine and to discuss its anticipated impact on the practice of periodontics.

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.

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.

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.

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.

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.

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 differential diagnosis of globulomaxillary radiolucencies.

The differential diagnosis of radiolucencies which occur in the globulomaxillary region includes a variety of odontogenic cysts and tumors, inflammatory lesions, and a number of nonodontogenic conditions. The accumulating embryologic and histopathologic evidence suggests that the development of fissural cysts in this region of the maxilla is highly unlikely. If they occur at all, such cysts must be extremely rare indeed and therefore do not belong on any clinician's list of differential diagnoses.

Foreign body gingivitis: an iatrogenic disease?

Gingival biopsy specimens from eight patients exhibiting a localized, erythematous, or mixed erythematous/leukoplakic gingivitis that was refractory to conventional periodontal therapy were examined histologically and by energy-dispersive X-ray microanalysis. Histologic examination revealed variable numbers of small, usually subtle, sometimes equivocal, and occasionally obvious foci of granulomatous inflammation. Special stains for fungi and acid-fast bacilli were consistently negative. In all cases, the granulomatous foci contained particles of foreign material that were often inconspicuous and easily overlooked during routine histologic examination. Energy-dispersive X-ray microanalysis of these foreign particles disclosed Ca, Al, Si, Ti, and P in most lesions. However, other elements such as Zr, V, Ag, and Ni were found only in specific biopsy specimens. By comparing the elemental analyses, clinical features, and history of the lesions, strong evidence for an iatrogenic source of the foreign material was found in one case, and good evidence in five cases. In the remaining two patients, the source of the foreign particles remains unresolved.

Dentin in chronic renal failure: an ultrastructural study.

Disturbances in the mineralization of hard tissues in patients suffering from chronic renal failure and in patients undergoing chronic hemodialysis are a well-established phenomenon. These disturbances are the result of complex pathophysiologic alterations in calcium and phosphorus metabolism. Disturbances in the dentin of teeth, analagous to those occurring in bone, were not recognized until 1983 when it was reported that a significantly thicker predentin layer was present in the teeth of patients with chronic renal failure and in patients being treated with chronic hemodialysis (1). The aim of the present study was to conduct a comparative ultrastructural (SEM) analysis of dentin in this group of patients. A wide spectrum of changes was detected, ranging from mild disturbances with increasing tubule irregularity and focal obliteration of tubule lumens, to widespread formation of dysplastic dentin exhibiting numerous mineralized, largely atubular globules with only occasional large, irregular tubules. In general, these changes appeared to reflect the type and effectiveness of treatment rendered (renal transplant or hemodialysis therapy). The findings suggest that dentin exhibits significant ultrastructural alterations when the underlying homeostatic regulation of calcium and phosphorus metabolism is disturbed in systemic disorders such as chronic renal failure.

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.

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.

Oral manifestations of chronic granulomatous disease.

Chronic granulomatous disease (CGD) has been recognized as a specific entity since 1957. Although a significant number of patients with this inherited disorder of leukocyte function exhibit oral manifestations which might be seen by the dentist, the dental literature contains no descriptions of this disease. The purpose of this article is to present a case of CGD exhibiting oral lesions, to document these lesions clinically and histopathologically, and to discuss the differential diagnosis of this disorder.

Scanning and transmission electron microscopy of odontogenic keratocysts.

The ultrastructural characteristics of the superficial cells of the epithelial lining of odontogenic keratocysts were studied. Examples of both the parakeratinized type and the less common orthokeratinized variant were examined. Scanning electron microscopy reveals that the morphology of the two cyst types is distinctly different. In parakeratinized cysts the transition of the epithelial cells into parakeratin is readily apparent and the epithelial surface is sparsely covered with parakeratin squames. In the orthokeratinized type the surface morphology is more uniform and is entirely covered with a leafy layer of keratin squames. The morphologic differences between the parakeratinized and orthokeratinized cysts may reflect differences in their biologic behavior.

Clinical and pharmacologic correlations in cyclosporine-induced gingival hyperplasia.

Cyclosporine-induced gingival hyperplasia was investigated in a clinical study of 100 patients over a period of 2 1/2 years. Seventy percent of the patients exhibited at least mild gingival hyperplasia. For doses within the therapeutic range, no direct correlation was found between the oral dose or the serum trough concentration of cyclosporine and the severity of gingival hyperplasia. The presence of dental plaque was found to be related to the presence of gingival hyperplasia, but only a weak correlation existed between the abundance of plaque and the severity of gingival hyperplasia. Children and especially adolescents had a greater risk of developing cyclosporine-induced gingival hyperplasia than adults had. In 21 patients followed for 1 to 18 months after cessation of cyclosporine therapy, induced gingival hyperplasia was found to be clinically reversible.

Pregnancy tumor: an analysis.

There is some disagreement about the validity of the clinical term "pregnancy tumor." On the basis of its clinical presentation and histologic appearance, some authors believe that it simply represents a pyogenic granuloma (PG), whereas others believe that the lesion is unique because of the apparent influence of female sex hormones. In an attempt to resolve this problem, a study was undertaken to determine whether a significant correlation exists between PG and pregnancy, and whether the clinical term applies to the other epulides. The study involved 42 epulides diagnosed clinically as pregnancy tumors. A chi-square analysis comparing 32 of these lesions with 757 epulides occurring in women revealed a significant disproportion in the number of PGs, whereas the number of peripheral ossifying fibromas and peripheral giant cell granulomas were within the expected range. Very few focal fibrous hyperplasias (fibromas) were diagnosed as pregnancy tumors. Clinical and behavioral features of pregnancy tumors diagnosed microscopically as PGs were also analyzed. The results indicated that the diagnosis of pregnancy tumor is valid clinically in describing a PG occurring in pregnancy, because it describes a distinct lesion not on the basis of histologic features but on etiology, biologic behavior, and treatment protocol.