Clinical performance of posterior metal-free polymer crowns with and without fiber reinforcement: one-year results of a randomised clinical trial.
OBJECTIVE
The aim of this study was to evaluate the clinical performance of posterior, metal-free polymer crowns with and without a glass-fiber framework, in comparison to metal-ceramic crowns.


METHODS
After randomisation, 80 single crowns, manufactured from a newly designed polymer composite, were set in posterior teeth. Half of these received a glass-fiber framework, while half were prepared without any framework stabilisation. All polymer crowns were adhesively luted with resin cement. As the control group, 40 conventional metal-ceramic crowns were inserted with hybrid cement. Documentation included failures and other complications, as well as gingival/plaque status and aesthetic performance.


RESULTS
During the 12-month observation period, eight polymer crowns and three metal-ceramic crowns showed clinically relevant complications. The most frequent complications were root canal treatments (n=4) and decementation (n=4) of the crowns. A total of two crowns (one polymer crown with fiber network and one crown of the control group) had to be replaced. After 12 months, polymer crowns with glass-fiber framework exhibited significantly higher plaque accumulation (p=0.005) and gingival index (p=0.04) than metal-ceramic crowns, while no significant differences could be demonstrated for polymer crowns without fiber reinforcement. Postoperative sensibility and aesthetic performance did not differ significantly between the groups.


CONCLUSIONS
Within a 12-month observation period, posterior polymer crowns with and without glass-fiber framework demonstrated acceptable stability and aesthetic performance. Polymer crowns with fiber framework showed significant higher plaque accumulation and gingival index than metal-ceramic crowns.
Department of Prosthodontics, University of Heidelberg, Im Neuenheimer Feld 400, Heidelberg, Germany. Brigitte_Ohlmann@med.uni-heidelberg.de
Brigitte
B
Ohlmann
Jens
J
Dreyhaupt
Marc
M
Schmitter
Olaf
O
Gabbert
Alexander
A
Hassel
Peter
P
Rammelsberg
D000328:Adult; D000368:Aged; D001641:Bicuspid; D003188:Composite Resins; D003442:Crowns / Q000009:adverse effects; D003773:Dental Plaque / Q000209:etiology; D019232:Dental Restoration Failure; D004311:Double-Blind Method; D005260:Female; D005891:Gingivitis / Q000209:etiology; D005898:Glass; D006801:Humans; D008297:Male; D016876:Metal Ceramic Alloys; D008875:Middle Aged; D008963:Molar; D010316:Particle Size; D011446:Prospective Studies; D012044:Regression Analysis; D019279:Resin Cements; D018709:Statistics, Nonparametric
D003188:Composite Resins; D016876:Metal Ceramic Alloys; D019279:Resin Cements; C516054:Trend HP; C009753:fiberglass