Soft tissue and incisor position changes in class I bimaxillary subjects after retraction using friction and frictionless mechanics

Aim: Bimaxillary protrusion is a common condition observed irrespective of race and ethnicity and is a chief concern for patients who seek orthodontic treatment. The aim of this study was to compare and evaluate changes in soft tissue structures and incisor positions in class I bimaxillary protrusion subjects undergoing orthodontic therapy when friction and frictionless mechanics were used. Methods: Two groups with a total of 40 patients aged 18­30 years diagnosed with class I bimaxillary protrusion treated by extracting first premolars were considered for this study. Patients treated with friction mechanics were included in Group 1 and those treated with frictionless mechanics in Group 2. The digital lateral cephalograms were calibrated and analyzed using Nemoceph software. Selected landmarks were marked on pre- and post-treatment cephalograms and assessed for intra- and inter-group soft tissue and incisor position changes. Student's t-test was used to analyze the collected data using SPSS 20 software. Result: Intragroup comparison revealed significant changes in both groups. Inter-group comparison of the selected parameters between groups 1 and 2 showed differences but without any statistical significance, except for the inter-incisal angle. Conclusion: Pre- and post-treatment comparison analysis revealed significant soft tissue changes in both groups. However, the comparison between friction and frictionless mechanics showed no statistically significant changes

Use of pulp tissue of deciduous teeth for gender determination - A comparative molecular analysis study

Aim: The present study aimed to evaluate the effectiveness of pulp tissue collected from deciduous teeth for the determination of gender using polymerase chain reaction (PCR). Materials and Methods: 140 extracted deciduous teeth were selected. The control group comprised 20 teeth that were subjected to DNA analysis immediately. Whereas Group I and Group II consisted of 60 teeth which were stored in the open environment and salt water, respectively, for a period of 3, 9, and 15 months. DNA was isolated and quantified followed by the amplification of X and Y chromosomes by PCR and compared with the actual gender of the child. The data were analysed using the Shapiro?Wilk test, the independent sample t?test, paired t?test, and the Chi?square test. Result: The PCR analysis results of Group I showed a more correct interpretation of gender as compared to Group II on storage for a period of 15 months. The PCR analysis results of the Control group showed a 100% accuracy rate as compared to the samples in Groups I and II. Conclusions: Gender could be effectively determined from the samples evaluated immediately after extraction. But the period of storage and the method of storage conditions affected the quality of isolated DNA and thus decreased the ability of gender determination