title: Wear of posterior metal-free polymer crowns after 2 years.
abstract: The objective of this study was to evaluate the clinical wear behaviour of posterior, metal-free polymer crowns and to compare it with that of metal-ceramic crowns. After randomization, a total of 120 single crowns were set in posterior teeth. These 120 crowns were divided into three groups: 40 polymer crowns with a glass-fibre framework (group 1), 40 polymer crowns without framework stabilization (group 2) and 40 metal-ceramic crowns (control group). Wear was measured by use of gypsum replicas and a 3D laser scanner at baseline and after 2 years. Statistical analysis was performed by use of a mixed-effects regression model. The mean total wear of posterior single crowns was -19.0 mum (+/- 18.5 microm) in group 1, -24.3 microm (+/- 31.5 microm) in group 2 and -7.0 microm (+/- 8.8 microm) in the control group. Statistical analysis revealed the mean total wear of the polymer crowns in groups 1 (P < or = 0.01) and 2 (P < or = 0.01) was significantly greater than in the control group. No significant difference was detected between groups 1 and 2 (P = 0.58). Age, gender and opposing teeth had no significant effect on wear behaviour.
authors.affiliation: Department of Prosthodontics, University of Heidelberg, Heidelberg, Germany. Brigitte_Ohlmann@med.uni-heidelberg.de
authors.forename: B
authors.initials: B
authors.lastname: Ohlmann
authors.forename: J-P
authors.initials: JP
authors.lastname: Trame
authors.forename: J
authors.initials: J
authors.lastname: Dreyhaupt
authors.forename: O
authors.initials: O
authors.lastname: Gabbert
authors.forename: A
authors.initials: A
authors.lastname: Koob
authors.forename: P
authors.initials: P
authors.lastname: Rammelsberg
mesh_terms: D000328:Adult; D000368:Aged; D003442:Crowns; D003766:Dental Occlusion; D017267:Dental Prosthesis Design; D019554:Dental Restoration Wear; D005260:Female; D005898:Glass; D006801:Humans; D008297:Male; D008422:Materials Testing / Q000379:methods; D016876:Metal Ceramic Alloys; D008875:Middle Aged; D011108:Polymers; D011446:Prospective Studies; D055815:Young Adult
chemical_list: D016876:Metal Ceramic Alloys; D011108:Polymers; C009753:fiberglass