Impact of ERCC1 gene polymorphisms on response to cisplatin based therapy in oral squamous cell carcinoma (OSCC) patients.

BACKGROUND AND OBJECTIVES: Cisplatin is one of the major drugs that used in the treatment of oral cancer.Excision repair cross-complementation group 1 (ERCC1) is a key DNA repair gene in the nucleotide excision repair pathway which is activated in the repair of intra- and interstrand DNA crosslink caused by platinum-based treatment. The aim of this study was to investigate the association between polymorphisms in ERCC1 (C118T & C8092A) genes and the response to cisplatin-based chemotherapy. METHODS: ERCC1polymorphisms (C118T & C8092A) were studied using PCR-RFLP method from 150 OSCC patients as cases as well as 150 normal tissues from the same patients were collected as controls for this study. Results: Frequencies of ERCC1 C118C, C118T and T118T genotypes were 60%, 28% and 12% in OSCC patients and 78%, 19% and 3% in the controls, respectively. The C118T & T118T genotype had a 1.69 and 4.97 -folds increased risk for OSCC. Frequencies of ERCC1 C8092C, C8092A and A8092A were 78%, 18% and 4% in the OSCC patients and 89%, 10%, amd 1% in the controls, respectively. The C8092A genotype showed a 1.97-fold increased risk for OSCC. INTERPRETATION & CONCLUSIONS: In conclusion, this study highlights the DNA repair gene polymorphisms that might play a role in mediating susceptibility to oral squamous cell carcinoma and cisplatin therapy. Our data suggest that the ERCC1 C118T, T118T and ERCC1 C8092A genotypes are genetic risk factors for Oral squamous cell carcinoma and ERCC1 118 C/T and C8092A polymorphisms have significant influence on clinical outcome.

Evaluation of accuracy of various impression techniques and impression materials in recording multiple implants placed unilaterally in a partially edentulous mandible- An in vitro study.

BACKGROUND: Various factors like implant angulation, type of impression material and tray type affects the implant impression accuracy. To date limited in-vitro studies were carried out on the implant impression accuracy of unilateral partially edentulous arches. The aim of this research was to evaluate the effects of 0o, 15o and 25o implant angulations on impression accuracy in simulated master casts of unilateral partially edentulous situation using different impression materials and tray selections. MATERIAL AND METHODS: 30 replicas (N = 30) of a resin matrix (control) containing four implant analogues placed unilaterally from the midline till the region of second molar at an angulation of 00, 00, 150 and 250 to the vertical axis of the ridge respectively were obtained by using three impression techniques (stock metal tray, closed custom tray, and open nonsplinted custom tray) and two different impression materials (Polyvinyl-siloxane and polyether). Specific dimensions of the resultant casts were measured using coordinated measuring microscope. Mean linear changes were calculated and statistically analyzed using analysis of variance (ANOVA) and Tukey's post-hoc procedures (p< 0.05). RESULTS: The casts obtained from all three impression techniques had significant differences in dimensions (p<0.05) as compared to that of master model irrespective of impression materials. Comparing the techniques with regard to the parallel implants, no statistical significant difference (p<0.05) was observed with custom tray techniques (closed/open). Whereas while comparing parallel versus non parallel, open tray technique showed superior accuracy compared to closed tray technique as the angulation increased more than 15 degrees. CONCLUSIONS: The influence of material and technique appeared to be significant for highly non axial implant angulations (p< 0.05), and increased angulation tended to decrease impression accuracy. The open tray technique was more accurate with highly nonaxially oriented implants for the small sample size investigated. Key words:Implant impressions, partially edentulous arch, angulated implants.

Estimation of serum superoxide dismutase and serum malondialdehyde in oral submucous fibrosis: a clinical and biochemical study.

BACKGROUND: To estimate the level of lipid peroxidation product (MDA) and the activities of antioxidative enzymes superoxide dismutase (SOD) and the correlation of these parameters in Oral Submucous fibrosis (OSF). AIMS: Estimation of MDA and SOD levels in OSF patients and controls. SETTINGS AND DESIGN: Patients above 15 years of age, who were diagnosed as OSF based upon thorough history, clinical examination and histopathological examination without any underlying systemic diseases, were included in the present study. Equal number of healthy subjects without any deleterious habits and without any clinically obvious oral lesions or systemic diseases were selected as the control group. MATERIALS AND METHODS: The estimation of MDA in serum was done by thiobarbituric acid reactive species method. SOD was assayed by inhibition and autoxidation of adrenaline method. STATISTICAL ANALYSIS USED: The data were analyzed with Student's t-test. RESULTS: Comparison of MDA, SOD among the OSF group and control group showed statistically significant increased levels of malondialdehyde and decreased levels of superoxide dismutase among the OSF groups. Significant changes were not seen in MDA and SOD levels between the different grades of OSF. CONCLUSIONS: From the present study, estimation of lipid peroxidation like MDA was done, which showed increased levels in the OSF group compared to the control group and antioxidant enzyme levels like SOD showed decreased levels in the OSF group compared to the control group. These can be considered as a subject of interest for their possible role in many of the precancerous and cancerous conditions.