Malignant transformation of calcifying cystic odontogenic tumour - a review of literature.

Calcifying cystic odontogenic tumour (CCOT) has been classified as an odontogenic tumour. Ghost cell odontogenic carcinoma (GCOC) is the malignant counterpart of CCOT. This paper aims to review the literature regarding malignant transformation of CCOT. A literature search was done via the National Library of Medicine PubMed interface, searching for articles relating to malignant transformation of CCOT. From these articles, references were obtained, and from their references lists, pertinent secondary references were also identified and acquired. After reviewing the literature, we found 26 cases of GCOC which developed from CCOT. Malignant transformation of CCOT was seen more commonly in the maxilla. Histologically, changes such as increased nuclear/cytoplasmic ratio, atypical mitotic figures have been reported after malignant transformation. Immunohistochemical analysis has shown an increased expression of ki-67 and p53 in tumour cells. Malignant transformation of CCOT, although rare, mostly takes place in recurrent and long standing cases.

P27 expression in pleomorphic salivary gland adenoma.

AIM OF THE STUDY: This study aims to characterise alterations in the immunohistochemical expression of p27 in normal tissue of the salivary gland surrounding pleomorphic adenoma and in the tumour cells of pleomorphic adenoma. MATERIAL AND METHODS: A retrospective study of data including 120 cases of pleomorphic adenomas (66 female, 54 male) retrieved from the files of the Oral Pathology Departments of Aleppo University, Syria and Al-Farabi Dental and Nursing College. Immunohistochemical expression against p27 was examined in the selected cases. The percentage of p27-positive nuclei was semi-quantitatively assessed by two independent observers and scores were given. The statistical analysis included the use of descriptive statistics and proportional frequencies. RESULTS: The results showed that P27 nuclear staining with high staining (moderate to strong positive staining in more than 50% of nuclei, depending on the percentage of nuclei for the cells) was noted in tumour duct cells of pleomorphic adenoma in 90 (75%) cases out of 120, while 30 (25%) cases showed low staining (positive staining in less than 5% of nuclei, depending on the percentage of nuclei for the cells). CONCLUSIONS: Our data suggests that p27 might have a minor role in the development of pleomorphic adenoma.

Knowledge and attitudes of Saudi dental undergraduates on oral cancer.

Oral cancer awareness among future dental practitioners may have an impact on the early detection and prevention of oral cancer. A cross-sectional survey was undertaken to assess the current knowledge of future Saudi dentists on oral cancer and their opinions on oral cancer prevention. A pretested questionnaire was sent to 550 undergraduate dental students in the fourth, fifth, and sixth year of the Al-Farabi College for Dentistry and Nursing, Riyadh, Saudi Arabia. Questions relating to knowledge of oral cancer, risk factors, and opinions on oral cancer prevention and practices were posed. Four hundred seventy-nine students returned the questionnaire (87.1 %). Eighty-one percent of respondents correctly answered questions relating to oral cancer awareness. Eighty-seven percent of respondents felt confident in performing a systematic oral examination to detect changes consistent with oral malignancy. Interestingly, 57 % of respondents had seen the use of oral cancer diagnostics aids. Thirty-seven percent of respondents felt inadequately trained to provide tobacco and alcohol cessation advice. There is a need to reinforce the undergraduate dental curriculum with regards to oral cancer education; particularly in its prevention and early detection. Incorporating the use of oral cancer diagnostic aids should be made mandatory.

Effect of vital bleaching on disintegration tendency of glass ionomer restorations.

INTRODUCTION: This study was designed to assess the effect of two bleaching agents on the disintegration tendency of three types of glass ionomers. MATERIALS AND METHODS: A total of 90 specimens were prepared by using a split Teflon ring with an internal diameter of 5 mm and a thickness of 2 mm. The tested materials were applied and bleached according to manufacturer's instructions. Dissolution measurements were made by calculating weight loss through different periods of the test; (one week, one month and three months) and they were analyzed by using one-way analysis of variance (ANOVA), followed by Tukey's post-hoc test. RESULTS: All glass ionomer materials exhibited a degree of dissolution. Opalescence Xtra increased the dissolution of Photac Fil and F2000 significantly, while Opalescence Quick had no effect on dissolution of glass ionomer restoratives. CONCLUSION: Bleaching effect on dissolution of glass ionomers is material and time dependant. Care should be taken by clinicians When bleaching teeth that are restored by glass ionomer, because this dissolution may affect the physical properties of these restorations.

Maspin as a tumour suppressor in salivary gland tumour.

Maspin is a protein that belongs to serin protease inhibitor (serpin) superfamily. The purpose of this study was to review the literature concerning the expression of maspin in salivary gland tumours. A literature search was done using MEDLINE, accessed via the National Library of Medicine PubMed interface. Statistical analysis was not done because only seven studies were available in literature, the collected data were different and the results could not be compared. Expression of maspin was down regulated in more aggressive salivary gland tumours. Maspin may function as a tumour suppressor in salivary gland tumours.

Immunohistochemical expression of p16 in Carcinoma Ex-pleomorphic Adenoma (undifferentiated and Adenocarcinoma Types).

OBJECTIVE: This study was aimed at characterizing alterations in the immunohistochemical expression of p16 in carcinoma ex-pleomorphic adenomas. STUDY DESIGN: A selected series of 27 cases of carcinoma ex-pleomorphic adenomas were examined. RESULTS: The results showed that p16 expression in non tumour duct cells was strongly positive nuclear staining in 23 (85%) cases out of 27 cases, that 3 (11.1%) had moderate staining, and that 1 (3.7%) had weak staining. p16 expression in carcinoma ex-pleomorphic adenomas was indicated as a negative nuclear staining in 22 (81.4%) cases out of 27cases, and 5 (18.5%) cases expressed moderate staining. CONCLUSION: This study suggests that alteration of p16 expression is detected in carcinoma ex-pleomorphic adenomas. p16 has a role in development of carcinoma ex-pleomorphic adenomas.