effect of carbon-graphite fiber reinforcement patterns on the transverse strength of provisional crown and fixed partial denture resins

This study was conducted to evaluate the effect of incorporating varying amounts [5, 10 and 15 wt%] of saline treated carbon-graphite fibers, in two different arrangement patterns, on the transverse strength of two provisional crown and fixed partial denture resins. Thirty five specimens of each resin were produced, 30 resin specimens were reinforced in linear and criss-cross fiber patterns with varying weight percentage of fiber contents. The mean transverse strength of the two resins increased significantly with 5 and 10 wt% fiber incorporation, but the differences in strength between 10 and 15 wt% were not statistically significant. The results obtained from this study showed promise of potentially practical techniques for strengthening provisional fixed partial dentures

Effect of porcelain fractures extent on the bond strength of composite bonded porcelain-to-porcelain repair system

This study was conducted to assess using the porcelain laminates as a repair material for fractured porcelains with/without metal exposure. Test samples were designed to simulate composite bonded porcelain-to- porcelain. A total of 80 samples were prepared and the shear bond strength was tested. One composite bonding resin, two etchants and two storage time intervals were investigated. Significant differences were found in bond strength between porcelain repairs with/without metal exposure. Scanning electron microscope revealed more profound etching characteristic produced by hydrofluoric acid, nevertheless the obtained bond strength was not highly significant than those etched with acidulated phosphate fluoride. Furthermore, the mean bond strength was higher at 1 month storage than at 3 months. This technique may be considered as a promising approach in repairing fractured porcelain facings without removal of the prosthesis