E-cadherin Expression in Premalignant Lesions, Premalignant Conditions, Oral Squamous Cell Carcinoma, and Normal Mucosa: An Immunohistochemical Study.

Background Oral squamous cell carcinoma (OSCC) is a multi-step process. Epithelial-mesenchymal transition (EMT) is an important step in the progression of OSCC. One of the components that influence EMT is E-cadherin. The aim of this study was to determine the expression of E-cadherin in oral submucous fibrosis (OSMF), various grades of epithelial dysplasia, OSCC, and to compare it with the expression in the normal mucosa. Material and methods E-cadherin immunohistochemical detection was done using a monoclonal antibody of clone EP-6TM and the PolyExcel HRP/DAB chromogen detection system. A total of 100 samples, were divided into four groups, which included epithelial dysplasia (group 2) (30 cases), oral submucous fibrosis (group 3) (OSMF-30 cases), and oral squamous cell carcinoma (group 4) (OSCC-30 cases), which was compared with normal mucosa (group 1) (10 cases). The positive control used for E-cadherin was ductal breast carcinoma. Results All the cases of normal mucosa, epithelial dysplasia, and OSMF showed positivity for E-cadherin expression. In OSCC, 97% of cases expressed E-cadherin except one case. Out of 30 cases of epithelial dysplasia, 53% of mild epithelial dysplasia had a moderate intensity of expression and 75% had a mild intensity of E-cadherin expression. In moderately differentiated OSCC, 82% of cases showed mild intensity. Tissue localization of the E-cadherin stain in the basal layer decreased from normal mucosa to grades of epithelial dysplasia and OSCC. The pattern of E-cadherin staining in all the cases of group I, group II, and group III was membranous. In 97% of OSCC cases, both membranous and cytoplasmic staining were seen. Conclusion E-cadherin expression was reduced in increasing grades of epithelial dysplasia, OSCC, and OSMF compared to that of normal mucosa. E-cadherin expression is reduced as the lesions progress to malignancy. Hence, E-cadherin can be considered a surrogate marker of malignancy.

Evaluating and comparing the morphological and histopathological changes induced by erbium:yttrium-aluminum-garnet laser and diamond bur on enamel, dentin and pulp tissue.

AIM: Lasers are used for different types of dental treatments. Using the erbium:yttrium-aluminum-garnet (Er:YAG) laser to remove dental hard tissue is simple, advantageous and influences the type of cavity preparation, whether conventional or conservative in nature. The aim of the present study was to evaluate and compare the morphological and histopathological changes in the enamel, dentin and pulp tissue of the teeth treated by Er:YAG laser and conventional burs. METHODS: A conventional class I cavity was prepared in orthodontic patients by laser and bur. The teeth were extracted and analyzed for morphological changes using a scanning electron microscope, ground sections and histopathological changes under a light microscope. RESULTS: The time with laser was longer than the conventional methods. The lased cavity showed irregular appearance with absence of smear layer which is suitable for the resin restoration. The ground section and the histopathological study showed no differences between the groups. CONCLUSION: The Er:YAG laser is effective in the removal of dental hard tissue without damaging the pulp when coupled with ideal energy output. It is widely used in different dental fields. It needs time to be accepted by dentist and patients and further studies are required to explore its advantages.

Immunohistochemical study of p53 and proliferating cell nuclear antigen expression in odontogenic keratocyst and periapical cyst.

INTRODUCTION: p53 protein is a product of p53 gene, which is now classified as a tumor suppressor gene. The gene is a frequent target for mutation, being seen as a common step in the pathogenesis of many human cancers. Proliferating cell nuclear antigen (PCNA) is an auxiliary protein of DNA polymerase delta and plays a critical role in initiation of cell proliferation. AIM: The aim of this study is to assess and compare the expression of p53 and PCNA in lining epithelium of odontogenic keratocyst (OKC) and periapical cyst (PA). MATERIALS AND METHODS: A total of 20 cases comprising 10 OKC and 10 PA were included in retrospective study. Three paraffin section of 4 µm were cut, one was used for routine hematoxylin and eosin stain, while the other two were used for immunohistochemistry. Statistical analysis was performed using Chi-square test. RESULTS: The level of staining and intensity were assessed in all these cases. OKC showed PCNA expression in all cases (100%), whereas in perapical cyst only 60% of cases exhibited PCNA staining. (1) OKC showed p53 expression in 6 cases (60%) whereas in PA only 10% of the cases exhibited p53 staining. Chi-square test showed PCNA staining intensity was more significant than p53 in OKC. (2) The staining intensity of PA using p53, PCNA revealed that PCNA stating intensity was more significant than p53. CONCLUSION: OKC shows significant proliferative activity than PA using PCNA and p53. PCNA staining was more intense when compared with p53 in both OKC and PA.

A study of sister chromatid exchange in patients with dental amalgam restorations.

STUDY BACKGROUND: Dental amalgam is still widely used as a restorative material in developing countries due to its low cost and ease of manipulation. The health risks associated with the components of this restorative material has always been a matter of concern. Our study was designed to address this question regarding dental amalgam. OBJECTIVE: To study sister chromatid exchange (SCE) as an indicator of systemic genotoxicity, due to the exposure from the components of amalgam restorations during its placement and chronic use. MATERIALS AND METHODS: Systemic genotoxicity in subjects exposed to amalgam during its placement (Group II; n=5) and subjects with chronic exposure to amalgam (Group III; n=5) were compared with controls (Group I; n=5) by SCE assay in cultured peripheral blood lymphocytes. RESULT: Subjects exposed to amalgam during its placement and subjects having chronic exposure to amalgam showed an increase in the frequency of SCE, but the change was not statistically significant (P=0.84, P=0.123 respectively). CONCLUSION: Systemic genotoxicity was not observed due to the components of amalgam restorations released during its placement and chronic use. The findings of this study can be considered as preliminary information on the systemic toxicity due to the components of amalgam restorations.