Evaluation of demineralization adjacent to orthodontic bracket and bond strength using fluoride-releasing and conventional bonding agents.

Background and Objectives: One of the most difficult problems encountered in orthodontic treatment with fixed appliance is the control of enamel demineralization around the brackets. Fluoride-releasing bonding adhesives were introduced to aid in the prevention of demineralization adjacent to orthodontic brackets. Hence, an in vitro study was conducted to evaluate and compare demineralization adjacent to the orthodontic bracket and the bond strength using fluoride-releasing adhesive and conventional adhesive. Materials and Methods: One hundred and twenty healthy extracted premolars were selected for the study and were divided into two groups, each group consisting of 60 teeth. Both groups were further divided into three subgroups consisting of 20 samples each. Samples of subgroups A and B were bonded with two prototypes of fluoride-releasing adhesives (i.e. Rely-a-bond and Tru-bond). Samples of subgroup C (ortho-one) were bonded with conventional non-fluoride-releasing adhesive. Group I samples were subjected to demineralization in an acidic medium (methyl cellulose buffered with acetic acid at a pH of 4.5) for 4 weeks, which were later observed under a stereomicroscope. Group II samples were tested for shear bond strength using the Instron Universal testing machine. Results: Both fluoride-releasing adhesives showed statistically significant lower enamel demineralization around the bracket when compared with the conventional adhesive. There was no statistically significant difference on comparing the demineralization between the two prototypes of fluoride-releasing adhesive. Evaluation of shear bond strength revealed that there was no significant difference between the subgroups. Conclusion: Fluoride-releasing adhesives might aid in the prevention of demineralization adjacent to the orthodontic bracket with acceptable bond strength.

Comparative study of effects of exercise and yoga on cardio-respiratory parameters.

Both Physical exercises and yogasanas are accepted by people to remain fit. The present study is conducted to find out the efficacy of the practice in human beings by comparing the cardio-respiratory parameters with that of subjects not performing any of these two. 30 male age, height and weight matched subjects were selected in each group viz. Control, Exercise and Yoga groups. Their Cardio-respiratory parameters were taken and compared between the groups. The results showed decrease in Pulse rate, Systolic as well as Diastolic blood pressure, and respiratory rate in subjects of exercise and yoga groups compared to that of control group. Significant increase in Respiratory capacities, % of Forced expiratory volume in 1st second, Maximum expiratory pressure and Peak expiratory flow rate are seen in both the groups. The results showed reduction in Respiratory minute volume significantly more in yoga group compared to exercise group while increase in Inspiratory capacity is significantly more in exercise group compared to yoga group.

Review analysis of medullary carcinoma thyroid--15-year Indian experience.

To emphasize the importance of adequate primary surgery in cases of medullary carcinoma of the thyroid, 44 cases of treated medullary carcinoma of thyroid were retrospectively reviewed in Government General Hospital, Chennai between 1987 and 2002. Patients who underwent total thyroidectomy with only central compartment dissection were compared with those who had undergone total thyroidectomy with meticulous triple compartment (bilateral lateral and central groups) nodal dissection. The group of total thyroidectomy with only central compartment dissection had high rate of lymph nodal recurrence and persistent hypercalcitoninaemia when compared with the group of total thyroidectomy with meticulous triple compartment nodal dissection. (Chi square value 4.503 with p<0.05).