PURSE 1998

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Browsing PURSE 1998 by Author "Amemiya, A."

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    The cases of unusual complex composite odontomes with well defined coronal indentation
    (University of Peradeniya, 1998-11-07) Mendis, B. R. R. N.; Sabanayagam, M. Indran.; Ranasinghe, A.; Amemiya, A.
    Complex composite odontomes are harmatomatous lesions that originate from aberrations of a normal or supernumerary tooth germ. They develop their complex form from multiple invaginations of the developing enamel organ at the bell stage of tooth development. The complex composite odontomes consist of a mass of irregularly arranged odontogenic hard and soft tissues that bear no morphologic similarity to even a rudimentary tooth. The mandibular molar region is the most frequent site of occurrence of these odontomes. The literature reveals that, the complex odontomes are commonly associated with permanent teeth. However, the occurrence of indentation on an odontome or on any other odontogenic malformation is unusual and has no reference in the literature. The two cases of complex composite odontomes presented are therefore unique and unusual. The inferolateral surface of both odontomes showed a well-defined coronal indentation. The crown of the impacted third molar tooth was in total occlusion with this indentation. This article presents the clinical, radiographic, morphological and histopathological aspects of the two unusual cases of complex composite odontomes, both seen in 22 year old males. Ground and decalcified sections of both odontomes stained with haematoxylin and eosin, when viewed with the light microscope showed, enamel, dentine and cementum arranged in a haphazard manner. While polarizing light microscopy confirmed the irregular arrangement of the enamel, fluorescent light microscopy revealed bands of fluorescence depicting incremental lines. Scanning electron microscopic studies of the indentation showed microridges. Some microridges were disrupted. Lacunae were seen where the tip of the cusp of the tooth was in contact with the indentation. The etiologic factors leading to the formation of odontomes are still unknown. However, environmental factors such as trauma and infection, interference in postnatal genetic control of tooth development and some hereditary factors play a considerable role. In the two cases presented, the odontomes were superior to fully formed third molar teeth. As the dental lamina was dividing into molar tooth germs an aberrant supernumerary development from the third molar tooth may have led to the formation of a complex mass of dental tissues. The formation of the odontome within what must have been a common follicle may have led to a close contact between the crown of the tooth and the developing odontome. Subsequently, the growth of the odontome may have been greater resulting in downward displacement of the tooth; whereas, the developing roots of the tooth may have pushed in the opposite direction. Thus formed impingement of the crown of the tooth on the odontome may have caused pressure and thereby initiating a process of remodeling of the odontome leading to theformation of an occlusal contact with the tooth.
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    Verrucous carcinoma in the oral cavity
    (University of Peradeniya, 1998-11-07) Baheerathan, N. N.; Mendis, B. R. R.; Amemiya, A.
    The verrucous carcinoma (VC) is a distinct variant of squamous cell carcinoma. It has low grade malignancy, slow growth and low metastatic potential. VC is chiefly exophytic. However VC can invade and destroy oral tissues including bone. Although it has been reported in other sites such as larynx and genitalia, the tumour is most frequently found in the oral cavity. As VC runs a relatively benign course, it could be effectively treated surgically and is prognostically favourable. Thirty-eighty cases ofVC of the oral cavity were reviewed for their clinical and histopathological characteristics. Data for this study was gathered from specimens available at the Department of Pathology at the Faculty of Dental Sciences from 1978 to 1998. All biopsies diagnosed histopathologically as VC was reviewed by using the histologic criteria defined by Ackerman in 1948. The criteria are: 1) Papillary or verrucous projections on the surface 2) No connective tissue invasion at the basement membrane zone 3) Mild or no dysplasia of the epithelium 4) Parakeratin or orthokeratin plugging on the surface 5) A broad and advancing front of the lesion into the subjacent connective tissue and 6) A chronic inflammatory cell infiltrate in the connective tissue, mainly lymphocytes and plasma cells. The cases which did not meet the above histopathologic criteria were eliminated.Clinical data were collected from the submitted biopsy request forms. The tumour occurred chiefly in older patients ( age range from 15 to 76 years,mean age 54.3) and more often in males than in females (32 males- 84.2% and 5 females-13.15%) The sex of one patient (2.65%)was not available. The site of lesion was known only in 19 patients. The most common site of occurrence was the buccal mucosa (10 cases). Macroscopic appearance of lesion was reported as either exophytic or warty and white. All the cases showed marked epithelial thickening with series of irregular papillary projections .All the biopsies showed broad rete ridges .These rete ridges showed no evidence of invasion at the connective tissue interface and basement membrane was intact.71.1% (27) of the cases showed no epithelial dysplasia and 28.9% (II) of biopsies showed mild epithelial dysplasia .Moderate to intense inflammatory cells infiltration was present in 84.2% (32)of cases, predominantly lymphocytes.Less intense inflammatory cells present in 15.8%(6) of cases.In 94.8%(36) of the cases,keratin plugging was present but the absence of keratin plugging did not exclude our diagnosis of VC