RESUMO
Aim and Objectives: The aims of this study were to compare the changes in occlusal parameters, TMJ status clinically in patients after the completion of orthognathic surgery, and patients undergoing only orthodontic treatment and with patients having normal occlusion, using T-Scan. Methodology: This prospective controlled clinical trial, consisting of three groups with a sample size of twelve. Group 1 consisted of patients who underwent orthognathic surgery and orthodontic treatment. Group 2 consists of patients who underwent only orthodontic treatment (camouflage). Clinical examination of the patient (TMJ and Occlusal status) and T-Scan was performed at the time of debonding of the orthodontic brackets, 6 months and 1-year after first evaluation for group 1 and 2 patients. Results: The collected data between groups are compared and interpreted. The statistical analysis was performed using STATA/IC version 16.1 statistical software. Intragroup comparison for the study variables occlusion time, disocclusion time and maximum bite force between different time periods (T1, T2, T3) for all the three intervention groups using repeated measures. Hypothesis testing for maximum bite force, occlusion time and disocclusion time in orthognathic group (Group 1) as compared to orthodontic group (Group 2) for three different time periods using repeated measures ANOVA and Bonferroni test showed P value < 0.05 which is statistically significant. Conclusion: In conclusion, evaluation of occlusion using T-Scan give us an insight of the discrepancies in occlusion which is useful during pre-operative planning and especially in the post-operative follow-up period during the retention phase. Examination of TMJ in these patients at various intervals is necessary as any minor occlusal disturbances may lead to TMJ disorders.
RESUMO
BACKGROUND: The bond strength between the zirconia core and ceramic veneer is the weakest component in the layered structure. Delamination of veneering ceramic is reported as one of the most frequent problems associated with Veneered Zirconia restorations. The aim of this study is to compare the shear bond strength of lithium di silicate porcelain to that of feldspathic porcelain on a zirconia Substrate. MATERIAL AND METHODS: Two groups (group A and B) of zirconia blocks with each group having 20 samples were fabricated according to Schmitz Schulmeyer method. Group A (n =20 ) samples were veneered with feldspathic veneering porcelain and Group B (n=20) samples were veneered with heat pressed lithium disilicate ceramic. The fabricated samples were then evaluated for shear bond strength in Universal Testing Machine. The values were then statistically analyzed using independent sample t-test. RESULTS: Results of the current study showed that mean shear bond strength of feldspathic porcelain 11.40±1.29 MPa is comparatively lower than the mean shear bond strength of the lithium disilicate group 18.81±1.76 MPa. The statistical analysis indicated that (p value<0.01) there is a statistically significant difference in the shear bond strength between the two groups. CONCLUSIONS: The heat pressed lithium disilicate veneering materials has a better shear bond strength compared to feldspathic veneering ceramic material when layered to a zirconia core and it can be used as a viable alternative material to feldspathic porcelain layering material in bilayered zirconia restorations. Key words:Zirconia, bilayered ceramics, lithium disilicate , shear bond strength, ceramic chipping.
