In vitro study of fracture strength of provisional crown materials.
OBJECTIVE
The purpose of this report was to evaluate the effect of the fabrication method and material type on the fracture strength of provisional crowns.


METHODS
A master model with one crown (maxillary left second premolar) was manufactured from Cr-Co alloy. The master model was scanned, and the data set was transferred to a CAD/CAM unit (Yenamak D50, Yenadent Ltd, Istanbul, Turkey) for the Cercon Base group. For the other groups, temporary crowns were produced by direct fabrication methods (Imident, Temdent, Structur Premium, Takilon, Systemp c&b II, and Acrytemp). The specimens were subjected to water storage at 37℃ for 24 hours, and then they were thermocycled (TC, 5000×, 5-55℃) (n=10). The maximum force at fracture (Fmax) was measured in a universal test machine at 1 mm/min. Data was analyzed by non-parametric statistics (α=.05).


RESULTS
Fmax values varied between 711.09-1392.1 N. In the PMMA groups, Takilon showed the lowest values (711.09 N), and Cercon Base showed the highest values (959.59 N). In the composite groups, Structur Premium showed the highest values (1392.1 N), and Acrytemp showed the lowest values (910.05 N). The composite groups showed significantly higher values than the PMMA groups (P=.01).


CONCLUSIONS
Composite-based materials showed significantly higher fracture strengths than PMMA-based materials. The CAD-CAM technique offers more advantages than the direct technique.
Department of Prosthodontics, Faculty of Dentistry, Selcuk University, Konya, Turkey.
Isil
I
Karaokutan
Department of Prosthodontics, Faculty of Dentistry, Medipol University, Istanbul, Turkey.
Gulsum
G
Sayin
Department of Prosthodontics, Faculty of Dentistry, Bezmialem Vakif University, Istanbul, Turkey.
Ozlem
O
Kara
Composite; Fracture strength, CAD-CAM; Methyl methacrylate; Provisional restoration; Temporary crown