Laboratory evaluation of shear bond strength of porcelain repair methods

Porcelain fracture is a relatively common problem in clinical dental practice. Various methods have been proposed for repairing porcelain fractures including direct composite resin repair or construction of a porcelain laminate veneer and its cementation with a resin cement. Evaluation of shear bond strength of porcelain repair methods was the purpose of this study. Twenty feldspathic porcelain discs (10 mm in diameter) were fabricated. The samples underwent air-born abrasion with an aluminum oxide and etching with HF, and were then ultrasonically cleaned and randomized into two groups: 1- repair with porcelain disc (7 mm in diameter) with light cure cement (Choice 2); and 2- repair with resin composite (Clearfil AP-X). We measured the shear bond strength of the samples by Zwick Roll at 0.5 mm/min crosshead speed. The resin composite group had the highest shear bond strength (12.91 MPa). We found no significant differences between the choice and composite groups (p=0.970). Our findings indicate that resin composite yields acceptable shear bond strength to be used in porcelain repair.