title: Margin designs and fracture resistance of incisal resin composite restorations.
abstract: This study measured the resistance to fracture of Class IV resin composite restorations prepared with either butt joints, bevels, or chamfer margins. Seventy extracted intact, non-carious maxillary central incisors, of approximately the same size, were collected and randomly divided into the following seven groups: 90 degrees butt joint (control)), 1 and 2 mm 45 degrees bevels, 1 and 2 mm 60 degrees bevels, and 1 and 2 mm chamfer margins. The teeth were restored with a hybrid resin composite and tested in an Instron Universal testing machine in a compressive mode at 45 degrees to the long axis. Statistical analysis indicated that there were no significant differences between the control group and any of the 1 mm bevel or chamfer margins and that the 2 mm bevel and chamfer margins yielded the highest fracture resistance.
authors.affiliation: Department of Restorative Dentistry, Loma Linda University.
authors.forename: D E
authors.initials: DE
authors.lastname: Tan
authors.forename: A H
authors.initials: AH
authors.lastname: Tjan
mesh_terms: D000704:Analysis of Variance; D003188:Composite Resins; D003737:Dental Cavity Preparation / Q000379:methods*; D003799:Dental Stress Analysis; D006801:Humans; D007180:Incisor; D008422:Materials Testing; D014082:Tooth Fractures / Q000517:prevention & control
chemical_list: D003188:Composite Resins