Evaluation of Two Protocols to Measure the Accuracy of Fixed Dental Prostheses: An In Vitro Study.
OBJECTIVE
The aim of this in vitro study was to compare two measurement protocols of the internal and marginal fit of three-unit zirconia fixed dental prostheses (FDPs).


METHODS
Forty-four FDPs were fabricated for standardized dies by two laboratory CAD/CAM systems: Cercon (n = 22) and Ceramill (n = 22). The fitting was tested using a replica technique (RT = technique 1) with a light-body silicone stabilized with heavy-body material. After producing the replicas, cross-sections were made in the buccolingual and mesiodistal directions. FDPs were cemented on definitive dies, embedded, and sectioned (CST = technique 2). The marginal and internal fits were measured under an optical microscope at 50x magnification with a special software program. Data evaluation was performed according to prior studies at a level of significance of 5%.


RESULTS
The mean internal gap width was 51 ± 36 μm for the RT and 52 ± 35 μm for the cross-section technique (CST) (p = 0.74). The mean marginal gap width was 27 ± 18 μm for RT and 30 ± 19 μm for CST (p = 0.19). Statistical tests showed no significant differences (p > 0.05).


CONCLUSIONS
Both techniques can be used for fit evaluation; however, the noninvasive RT is suitable for clinical use.
Department of Prosthodontics, Munich Dental School, Munich, Germany.
Joana
J
Schönberger
Department of Prosthodontics, Munich Dental School, Munich, Germany.
Kurt-Jürgen
KJ
Erdelt
Private Practice, Munich, Germany.
Daniel
D
Bäumer
Department of Prosthodontics, Munich Dental School, Munich, Germany.
Florian
F
Beuer
D017076:Computer-Aided Design; D018772:Dental Marginal Adaptation; D003779:Denture Design / Q000379:methods; D003830:Denture, Partial, Fixed; D006801:Humans; D066298:In Vitro Techniques
Computer-aided design/computer-aided manufacturing; cross-section technique; marginal and internal fit measurement; pre-sintered zirconia; replica technique