ABSTRACT
INTRODUCTION: The use of zirconia based all-ceramic restorations are preferred nowadays owing to superior biologic and esthetic properties. However, these restorations have also reported higher incidences of fracture and chipping. The clinical success may be enhanced by optimizing the core design, through the introduction of monolithic zirconia, or the layered crowns can be strengthened by adding the cervical collar to them. OBJECTIVE: This study was performed with the objective to compare and evaluate the fracture load of monolithic and bilayered zirconia crowns with and without a cervical collar. METHODS: A prospective observational study was carried out to compare 45 fabricated zirconia crowns of three different designs on a customized metal mould. The samples were oriented on the metal mould and subjected to confocal microscope for the evaluation of marginal integrity followed by cementing the crown on the metal mould and subjecting it to the universal testing machine for the analysis for the flexural strength. Data were analyzed using one way Anova and t- test for inter and intra groups. The significance level was set at P ≤ 0.05. RESULTS: The monolith zirconia crowns and layered zirconia crowns with cervical collar reported more flexural strength. CONCLUSION: The amount of force required to fracture the zirconia crowns was higher in the case of monolith zirconia crown and layered zirconia crown with cervical collar as compared to the layered zirconia crown without cervical collar.
ABSTRACT
AIM: The aim of this study is to compare the incidence of postoperative pain using the ProTaper Next (PTN), WaveOne Gold (WOG), and Self-Adjusting File (SAF) systems. MATERIALS AND METHODS: Two hundred and fourteen patients with irreversible pulpitis were selected for single-visit endodontics. The teeth were blindly assigned to three groups based on the instrumentation system used: Group A (PTN), Group B (WOG), and Group C (SAF). Participants were asked to note the incidence of the pre- and postoperative pain on a visual analog scale at different time intervals. Paired t-test and one-way ANOVA were used along with post hoc Tukey's test. RESULTS: The greatest mean pain in Group A (PTN) and Group B (WOG) was found to be maximum in the first 24 h with a significant reduction in pain at the subsequent observation time points of 48 h, 72 h, and 7 days. Group C (SAF) showed minimum pain followed by Group B followed by Group A which showed comparatively higher pain scores even at the end of 7 days. CONCLUSIONS: In single-visit endodontics, SAF system may prove to be a better system compared with PTN and WOG as it produces minimal postoperative pain, thus improving the overall acceptance of endodontic treatment.
