Aim- To evaluate the removal of gutta percha by hand file system, rotary file system and reciprocating file system from root canals by using CBCT. Materials and Method: Root canals of 42 extracted human mandibular premolars  were prepared using the ProTaper Universal rotary system and then obturated. Root filling quality was confirmed on CBCT images. Specimens were divided into 3 groups (n = 14) according to the system used for filling removal, group 1: H File, group 2: MTwo rotary retreatment file, and group 3:WaveOne file. Each specimen was sent for CBCT Analysis. Statistical Analysis Used: Evaluation of data was done statistically using One-way Analysis of Variance and Tukey’s post hoc test. Results: There was statistical difference in all the groups (P>0.05). All systems demonstrated presence of remnants of filling material. Mean reduction in the volume of GP after retreatment of Group I was 0.006mm3, Group II was 0.002mm3 Group III was 0.003mm3. Conclusion: The system responsible for a better removal of root canal filling material was the MTwo Retreatment file system, followed by the WaveOne system and H File.

Aim- To evaluate the removal of gutta percha by hand file system, rotary file system and reciprocating file system from root canals by using CBCT. Materials and Method: Root canals of 42 extracted human mandibular premolars were prepared using the ProTaper Universal rotary system and then obturated. Root filling quality was confirmed on CBCT images. Specimens were divided into 3 groups (n = 14) according to the system used for filling removal, group 1: H File, group 2: MTwo rotary retreatment file, and group 3: WaveOne file. Each specimen was sent for CBCT Analysis. Statistical Analysis Used: Evaluation of data was done statistically using One-way Analysis of Variance and Tukey’s post hoc test. Results: There was statistical difference in all the groups (P>0.05). All systems demonstrated presence of remnants of filling material. Mean reduction in the volume of GP after retreatment of Group I was 0.006mm3, Group II was 0.002mm3 Group III was 0.003mm3. Conclusion: The system responsible for a better removal of root canal filling material was the MTwo Retreatment file system, followed by the WaveOne system and H File.

Background: To conserve the tooth structure, bonded restorations are popular nowadays. Bonding to enamel is predictable by acid-etch technique. However, bonding to dentin remains a challenge. Aim: To determine the better bonding agent between universal bonding agent and total-etch bonding agents based on shear bond strength using universal testing machine. Methodology: Eighteen human permanent mandibular molars were sectioned longitudinally to obtain thirty-six samples. Samples were randomly divided into three groups according to the bonding agent, Group A (Unbonded), Group B (Universal bonding agent) which was again divided into Subgroup B1 (Superficial dentin), Subgroup B2 (Deep dentin) and Group C (total-etch bonding agent) which was again divided into Subgroup c1 (Superficial dentin) ,Subgroup c2 (Deep dentin). Composite block was built up and samples were mounted in acrylic resin. Thermocycling was done and then samples were subjected to Universal testing machine. Statistical Analysis: The data was analysed using One-way ANOVA and Post hoc tests. Result: Universal bonding agent showed higher mean shear bond strength than total-etch bonding agent at both superficial and deep dentin level. Conclusion: The shear bond strengths of Universal Bonding agent and total-etch bonding agents were affected by the dentin level i.e., superficial and deep dentin.