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A practice‐based clinical evaluation of the survival and success of metal‐ceramic and zirconia molar crowns: 5‐year results
Author(s) -
Rinke S.,
Kramer K.,
Bürgers R.,
Roediger M.
Publication year - 2016
Publication title -
journal of oral rehabilitation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.991
H-Index - 93
eISSN - 1365-2842
pISSN - 0305-182X
DOI - 10.1111/joor.12348
Subject(s) - medicine , dentistry , confidence interval , crown (dentistry) , molar , cubic zirconia , orthodontics , ceramic , materials science , composite material
Summary This practice‐based study evaluates the survival and success of conventionally luted metal‐ceramic and zirconia molar crowns fabricated by using a prolonged cooling period for the veneering porcelain. Fifty‐three patients were treated from 07/2008 to 07/2009 with either metal‐ceramic crowns ( MCC ) or zirconia crowns ( ZC ). Forty‐five patients (26 female) with 91 restorations (obser‐vational period: 64·0 ± 4·8 months) participated in a clinical follow‐up examination and were included in the study. Estimated cumulative survival ( ECS v), success ( ECS c) and veneering ceramic success ( ECVCS c) were calculated (Kaplan–Meier) and analysed by the crown fabrication technique and the position of the restoration (Cox regression model) ( P < 0·05). Five complete failures ( MCC : 2, ZC : 3) were recorded (5‐year ECS v: MCC : 97·6%, (95% confidence interval (95%‐ CI ): [93%; 100%]/ ZC : 94·0%, (95%‐ CI ): [87%; 100%]). Of the MCC s ( n = 41), 85·0%, [95%‐ CI : (77%; 96%)] remained event‐free, whereas the ECS c for the ZC s ( n = 50) was 74·3% (95%‐ CI ): [61%; 87%]. No significant differences in ECS v ( P = 0·51), ECS c ( P = 0·43) and ECVCS c ( P = 0·36) were detected between the two fabrication techniques. Restorations placed on terminal abutments ( n = 44) demonstrated a significantly lower ECVCS c ( P = 0·035), (5‐year VCF ‐rate: 14·8%) than crowns placed on tooth‐neighboured abutments ( n = 47), (5‐year VCF ‐rate: 4·3%). In the present study, zirconia molar crowns demonstrated a 5‐year ECS v, ECS c and ECVCS c comparable to MCC s. Irrespective of the fabrication technique, crowns on terminal abutments bear a significantly increased risk for VCF s. Clinical investigations with an increased number of restorations are needed.