title: Complication rate of molar crowns: a practice-based clinical evaluation.
abstract: This practice-based study evaluates the initial clinical performance of conventionally luted metal-ceramic and zirconia molar crowns fabricated with a prolonged cooling period of the veneering porcelain. Forty-nine patients were treated (group A: high precious alloy + low fusing porcelain; group B: zirconia crowns). All zirconia crowns were veneered with a modified porcelain firing cycle including a 6-minute cooling period. Ninety-two restorations (74 vital abutments/18 nonvital abutments) were evaluated after a mean observation period of 18.2 +/- 4.6 months. No complete failures or loss of vitality were recorded in either group. Two events were recorded in group A (1 loss of retention/1 minor ceramic chipping < 2 mm2). The third event occurred in group B (minor ceramic chipping <2 mm2). All ceramic defects could be polished intraorally. Statistical analysis revealed non-significant differences in success rates (p = 0.91) of metal-ceramic and zirconia crowns fabricated with a modified porcelain firing. The modified firing of the zirconia porcelain seems to decrease the risk for early ceramic chipping in the molar area, leading to a technical complication rate comparable to that of metal-ceramic crowns.
authors.affiliation: rinke@ihr-laecheln.com
authors.forename: S
authors.initials: S
authors.lastname: Rinke
authors.forename: S
authors.initials: S
authors.lastname: Schäfer
authors.forename: M
authors.initials: M
authors.lastname: Roediger
mesh_terms: D000328:Adult; D000368:Aged; D003080:Cold Temperature; D017076:Computer-Aided Design; D003442:Crowns / Q000009:adverse effects*; D003776:Dental Porcelain; D017267:Dental Prosthesis Design; D017268:Dental Prosthesis Retention; D019232:Dental Restoration Failure; D003801:Dental Veneers; D003807:Dentin Sensitivity / Q000209:etiology; D005899:Glass Ionomer Cements; D006358:Hot Temperature; D006801:Humans; D053208:Kaplan-Meier Estimate; D016876:Metal Ceramic Alloys; D008875:Middle Aged; D008963:Molar; D016016:Proportional Hazards Models; D015019:Yttrium; D015040:Zirconium
chemical_list: D005899:Glass Ionomer Cements; D016876:Metal Ceramic Alloys; C499362:yttria stabilized tetragonal zirconia; D003776:Dental Porcelain; D015019:Yttrium; D015040:Zirconium