This in-vitro study investigated the effect of immersion and spray atomization technique of disinfection using 0.5% of sodium hypochlorite solution on compression resistance of polyvinyl siloxane and polyether interocclusal recording materials. This study comprised of a total of 60 samples, wherein 30 samples each of polyvinyl siloxane and polyether underwent compression resistance. These 30 samples of each were again divided into 3 subgroups comprising of 10 specimens each-a control group, a group subjected to spray atomization disinfection technique for 10 mins and a group subjected to immersion technique for 10 mins following which they were subjected to compression resistance in a universal testing machine. One-way ANOVA and Post-Hoc Tukeys test were used for statistical analysis. Results showed that Polyvinylsiloxane interocclusal recording material showed better resistance to compression than polyether interocclusal recording material and Immersion technique of disinfection was better for polyvinylsiloxane and spray atomization technique of disinfection for polyether. Hence it could be concluded that Polyvinylsiloxane material can be used as an interocclusal recording material because of its greater resistance to compression and can be subjected to immersion technique of disinfection.

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Objective: To compare and evaluate the fracture toughness and flexural strength of PMMA and bisacryl composite provisional restorative materials with and without reinforcement of Kevlar fibre. Methodology: 40 test specimens of PMMA and bisacryl composite for fracture toughness testing and 40 rectangular specimens of PMMA and bisacryl composite for flexural strength testing were fabricated respectively. Each main group was again divided into 2 sub groups A & B; where A is control group and B is the test group with Kevlar fibre reinforcement. The fibre reinforced specimens were prepared by precutting the fibres into 12mm and 23mm length and wetted using the polymer monomer mix for the PMMA and a bonding agent for the bisacryl resin and then placed in the mold cavity. In both tests, unreinforced resins were used as control group. Specimens were stored in water at 37˚C for 24 hours before testing. The specimens were loaded in universal testing machine. The mean fracture toughness and mean flexural strength were compared by one way analysis of variance followed by the Tukeys standardized range test. Results: The mean fracture toughness and flexural strength values obtained were significantly higher for bisacryl composite when compared to PMMA. Similarly after Kevlar reinforcement bisacryl composite proved to be better.

Objective: To compare and evaluate the bond strength of a fiber post cemented to different post space diameters using two commercially available resin cement. Methodology: 60 freshly extracted maxillary central incisor teeth with similar dimensions were selected and sectioned horizontally from CEJ. Endodontic treatment was done on all specimens and divided into two groups Group 1 and 2 (n=30) based on the post space diameter (0.9mm and 1.1mm). Each group was subdivided into two 1A, 1B, 2A, 2B (n=15) according to the cement used. Following the post space preparations, the canals were rinsed and dried. The adhesive resin cement was applied and posts were seated to full depth and excess cement was removed. After 24 hours specimens underwent 10,000 thermal cycles and preserved in saline solution. Specimens were mounted into universal testing machine and tensile force at a crosshead speed of 1 mm/ min was applied to the posts until they debond from the root canals. Data was analyzed using ANOVA test, Independent t test and Tukey HSD test. Result: The result shows increased bond strength in snug fit than passive fit. ie; more bond strength was observed in Group 1A (mean =26.75 KgF) and Group 1B (mean =15.72 KgF) where post size and peeso reamer drill size were same. When comparing two cements RELYX shows more bond strength (1A=26.75, 2A=14.82) than PANAVIA cement (1B=15.72, 2B=10.51). Conclusion: A post with snug fit post space preparation shows better resistance to pull out test than over prepared post space preparation. Cement RELYX U-200 shows higher tensile bond strength than PANAVIA-F cement.