The effect of wetting technique on fracture strength of fiber Reinforced Composite Fixed Partial Dentures. An In vitro study

One of the most important factors in Fracture resistance of FRC bridge is the wetting technique consist of preimpregnation and hand impregnation. Along with points of previous researches in this field,the goal of the present study performed in Tehran Islamic Azad University, Dental Faculty, was to determine the effects of wetting technique on the fracture Resistance of posterior FRC Bridges. In this experimental study, Fourty sound, intact teeth, free of any crack or restoration were collected & After Fabricating PDL, were embeded in PMMA, up to 1 mm below CEJ. Samples were then rardomly divided in two groups of preimpregnated & hand impregnated. The preparation design for abutment teeth included proximal Box with exact dimentions. Preimpregnated group was Fabricated with Fiber inside the capsule & handimpegnated with Fbers which wetted in Resist for 15 minutes. All the specimens were subjected to thermal Cycling (5000 cycles, /5, dwell time 30s, interval 25). Fracture testing was performed in a universal testing machine (Instron 1195) with a cross head speed of 1 mm/min. Bridges fracture resistance, expressed in Newton, was investigated and data were subjected to statistical analysis. the research, conducted on 20 FRC Bridges, revealed the amonnt of fracture Resistance in Preimpregnated group as 1305 197 and that of hand impregnated group as 870 157 (p<0.001) The most Failure mode observed, was crack and Fracture in the surface layer of FPDS in distal segmet of pontics. wetting technique not only results in an increarse in tooth Fracture, but also influences the Failure mode. Therefore the application of preimpregnated technique in clinical treatment and investigating its long- term effects are recomended.