title: Compressive fracture resistance of the marginal ridge in large Class II tunnels restored with cermet and composite resin.
abstract: Compressive fracture resistance of the marginal ridge was studied in large tunnel preparations, before and after restoration with cermet (Ketac Silver, ESPE), a universal hybrid composite (Superlux, DMG) and an experimental composite. Each group was represented by six tunnels in extracted upper premolars. The tunnels were prepared by the use of round burs up to size #6. Remaining ridge width was 1.5 mm and ridge height 1.7 mm in the contact area. The ridge was loaded to fracture by a rod placed perpendicular to the ridge. Generally this resulted in a shear fracture of the restoration. There was no significant reinforcement of the ridge by the cermet whereas the composites both reinforced by the same magnitude, averaging 62%. It was concluded that the ridge could be considered a "megafiller" where contact need to be preserved and contour protected against proximal and occlusal wear of the restoration. Clinically there would therefore be good reasons to save even ridge areas with very low inherent strength. Based on the present study composite resin might therefore be the filling material of choice for such tunnel preparations.
authors.affiliation: Department of Oral Technology and Biomaterials Science, Faculty of Odontology, University of Lund, Malmö, Sweden.
authors.forename: L E
authors.initials: LE
authors.lastname: Ehrnford
authors.forename: H
authors.initials: H
authors.lastname: Fransson
mesh_terms: D001641:Bicuspid; D016722:Cermet Cements; D003188:Composite Resins; D003737:Dental Cavity Preparation / Q000009:adverse effects / Q000379:methods*; D003793:Dental Restoration, Permanent / Q000009:adverse effects / Q000379:methods; D003799:Dental Stress Analysis; D006801:Humans; D008437:Maxilla; D019279:Resin Cements; D014082:Tooth Fractures / Q000209:etiology / Q000517:prevention & control*
chemical_list: D016722:Cermet Cements; D003188:Composite Resins; D019279:Resin Cements; C083372:Superlux Universal Bond 2