TO COMPARE AND EVALUATE THE FRACTURE TOUGHNESS AND FLEXURAL STRENGTH OF PROVISIONAL RESTORATIVE MATERIALS WITH AND WITHOUT REINFORCEMENT OF KEVLAR FIBRES - AN INVITRO STUDY

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 bis-acryl 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.