Effect of intermaxillary tooth-size discrepancy on accuracy of prediction equations for mixed dentition space analysis for Davangere population.

Context: In the mixed dentition period, malocclusion is in dormant stage, any interception should be preceded by a mixed dentition space analysis. Aims: To derive new regression equation in sample subjects (indigenous group) with no intermaxillary tooth size discrepancy (Bolton's ratio) residing in Davangere and to evaluate its accuracy. To assess the difference of tooth dimensions between males and females and difference between right and left of dental arches. Design: Descriptive study. and Methods: One hundred and fifty children (11-15 years) were included and dental casts were made. A digital Vernier caliper was used for the measurement of teeth. Bolton's ratio was calculated. Group A: Casts without Bolton's discrepancy and Group B: Casts with Bolton's discrepancy. Used: The data were analyzed with the SPSS software version 22.0. New regression equations were derived using correlation and regression analysis. Results: No statistically significant difference was recorded between the actual and predicted mesiodistal widths (MDWs) of permanent canine and premolars in maxilla and mandible, with/without Bolton's discrepancy. Males had statistically significant higher mean in maxillary and mandibular canine dimensions than female and no statistically significant difference between right and left side of dental arches was found. Conclusion: New regression equation was formulated for Davangere population, in which actual and predicted widths of permanent canines and premolars were found to be almost similar when established from sample with/without Bolton's discrepancy. In MDWs, the canine showed significant sexual dimorphism and no clinically significant variations were seen in the right and left sides of both the arches.

Comparison of CPP-ACP, Tri-Calcium Phosphate and Hydroxyapatite on Remineralization of Artificial Caries Like Lesions on Primary Enamel -An in vitro Study.

OBJECTIVES: To compare CPP-ACP, Tri-calcium phosphate and Hydroxyapatite on remineralization of artificial caries like lesions on primary enamel. STUDY DESIGN: Ten extracted Primary molars coated with nail varnish, leaving a window of 2×4 mm on buccal and lingual surface were immersed in demineralizing solution for 96 hours and sectioned longitudinally to obtain 40 sections (4 sections per tooth) and were randomly divided into 4 groups (A to D) n=10; Group A: negative control, Group B: CPP-ACP, Group C: Tri-calcium phosphate, Group D: Hydroxyapatite. Sections were subjected to pH cycling for 10 days and were evaluated by polarized light microscope before and after treatment. RESULTS: Intra group comparison of demineralization and remineralization was done by paired t-test. One way ANOVA was used for multiple group comparisons followed by post HOC TUKEY'S Test for group wise comparisons. Remineralization was found more with Group D followed by Group B, C and A. CONCLUSION: Hydroxyapatite showed better remineralization when compared to CPP-ACP and Tri-calcium phosphate.

Effect of Whitening Dentifrice on Micro Hardness, Colour Stability and Surface Roughness of Aesthetic Restorative Materials.

INTRODUCTION: Whitening agents present in the novel whitening dentifrices may have deleterious effects over the aesthetic restorations. AIM: The present study evaluated the invitro effect of whitening dentifrice on micro hardness, colour stability and surface roughness on aesthetic restorative materials. MATERIALS AND METHODS: Forty specimens each of compomer and of composite were prepared using brass mould. Specimens were equally divided into 4 groups. Group I (20 disks of compomer are subjected to brushing with conventional tooth paste) Group II (20 disks of composite subjected to brushing with conventional tooth paste), Group III (20 disks of compomer subjected to brushing with whitening tooth paste). Group IV (20 disks of composite subjected to brushing with whitening toothpaste). Each group was further divided into two subgroups, where 10 sample were subjected for two weeks of brushing with respective tooth paste and other 10 were subjected for four weeks of brushing. For the evaluation of micro hardness, colour stability and surface roughness, micro hardness testing machine, spectrophotometer and surface testing machine were used respectively. Initial and final readings were taken for each specimen and difference obtained was subjected to statistical analysis. One-way ANOVA was used for multiple group comparison followed by post-hoc Tukey's-test. The paried t-test was used for intra group comparison and unpaired t-test for comparing independent sample groups. RESULTS: The compomer and composite showed no significant difference in micro hardness either with conventional or whitening tooth paste both at two and four weeks. Although there was a highly significant colour change observed after using whitening tooth paste for both compomer and composite. Regarding surface roughness, there was a significant change in roughness in both conventional and whitening tooth paste with compomer and composite. However, whitening tooth paste had a significant change in surface roughness compared with conventional tooth paste. Roughness further increased at four weeks interval when compared to two weeks. CONCLUSION: Colour, surface-roughness and micro-hardness are the inherent properties of the aesthetic restorative materials. Use of whitening tooth paste will cause colour change and surface roughness of restorative material making it prone to deformation and also affects the clinical success of restoration.