Analysis of enamel rod end pattern for personal identification.

BACKGROUND: Microscopically, groups of enamel rods run in unique direction, which differ from adjacent group of enamel rods and results in forming different patterns of enamel rod endings on tooth surface. These are called as tooth prints and they help in personal identification in forensic odontology. AIMS AND OBJECTIVES: The aim of the present study is to analyze the enamel rod end pattern on the tooth surface for personal identification and to analyze the familial inheritance of enamel rod end pattern. MATERIALS AND METHODS: In the present study, 100 different families were considered for the analysis of tooth print pattern. In each family, four members were present. The maxillary central incisor, canine and first premolar were selected. Enamel rod end pattern was recorded using acetate peel technique and analyzed using Verifinger® standard SDK version 6.7 software. STATISTICAL ANALYSIS: Data analysis was performed using the SPSS software. Contingency coefficient statistical analysis was used for the comparison of tooth print pattern in incisors, canines and premolars based on age and gender. P < 0.05 was considered statistically significant. RESULTS: The present study showed that a tooth print is composed of combination of eight distinct subpatterns, namely wavy branched, wavy unbranched, linear branched, linear unbranched, whorl open, whorl closed, loop and stem-like pattern. Wavy branched pattern was found to be the most predominant pattern in incisors, canines and first premolars in our study. Familial tendency of tooth print pattern in incisors, canines and premolars was noticed in 65%, 66% and 52% of the families, respectively. CONCLUSION: Tooth prints are unique to an individual and can be used as a valuable inexpensive tool in forensic odontology for personal identification.

Transforming growth factor-ß-1 polymorphisms are infrequent but exist at selected loci in oral submucous fibrosis.

BACKGROUND: Oral submucous fibrosis (OSF) may be considered a collagen metabolic disorder resulting from areca-nut alkaloid exposure and individual variation in collagen metabolism. Due to the complexity of OSF pathogenesis, it is important to elucidate independent and interactive effects of polymorphisms of collagen-related genes on OSF risk. MATERIALS AND METHODS: This study is focused on seven polymorphisms (SNPs) of transforming growth factor-beta-1 (TGF-beta-1) gene in patients with oral submucous fibrosis (OSF), belonging to south Indian ethnic extraction. The mean age at presentation was 43.9 years, range 23-72 years (n=50, M:F ratio, 2.6:1). DNA samples from 50 subjects of the same ethnic group and comparable demographic features who have had practiced the habit of areca-chewing of almost equal duration, but remained free of disease constituted the controls. All DNA samples were collected progressively and purified from peripheral blood employing standard protocols and tested for SNPs. They included two polymorphisms in the promoter region (C-509T and G-800A), three polymorphisms in exon-1 (Arg25Pro(G915C), Leu10Pro(T869C), Glu47Gly(A979G) and two in 5 ¢UTR regions (C→T(rs13306708) and G→A (rs9282871). The extracted DNA samples along with the primers underwent PCR amplification and the genotypic and allelic frequencies were calculated. All calculations were performed using the SPSS software. The PCR products were purified and subsequently sequenced using Flour S™ multi-imager system (Biorad). The sequenced data were analyzed using the BioEdit sequence analysis software. RESULTS: Out of the seven polymorphisms analyzed, six such as two in the promoter region, three in exon-1 and one in 5¢UTR were found to have a " P" value above 0.05 and hence were not significant. The C→T transition (rs13306708) in the 5¢UTR region recorded a " P" value of 0.03 on comparison and hence was found to be significant. The allelic frequencies for this C→T transition in patients were 68.7% C and 31.2% T (27CC, 15CT, 8TT) and that in controls were 89.5% C and 10.4% T (42CC, 6CT, 2TT). CONCLUSIONS: The polymorphism in 5¢UTR C-T in TGF beta 1 gene has a significant association with OSF, being a prime determinant in the pro-angiogenic pathway which has got direct bearing with the pathophysiology of the disease. The proximity of this polymorphism to the transcription site and the associated risk involved is discussed.