Fracture strength of all-ceramic posterior inlay-retained fixed partial dentures.

Abstract

OBJECTIVES:

The purpose of this in vitro study was to compare the quasi-static (QSFS) and fatigue fracture strength of all-ceramic resin-bonded three unit inlay-retained fixed partial dentures (IRFPDs) made from a heat-pressed lithium-disilicate based glass-ceramic (LDGC) and a CAD/CAM-manufactured yttrium-oxide partially stabilized zirconia framework (YPSZ).

METHODS:

Identical IRFPD-models of the maxilla were used. They consisted of a second premolar, a missing first molar and a second molar (Co-Cr-Mo alloy) integrated in a low melting alloy base. Roots were covered with a soft silicone-layer to simulate an artificial parodontium. Premolars had an occlusal-distal inlay-preparation and molars a mesial-occlusal inlay-preparation. Thirty-two IRFPDs were made from each ceramic using two different connector dimensions: 3mmx3mm (LDGC_9, YPSZ_9); 4mmx4mm (LDGC_16, YPSZ_16). All IRFPDs were cemented adhesively to the IRFPD-models, using composite resin cement. QSFS was tested in a universal-testing-machine (UTM) for six specimens. The other specimens were fatigued either with cyclic loading at 250N (n=4) in a chewing simulator or at 600N (n=6) using the UTM, and group YPSZ additionally at 1500N.

RESULTS:

The medians of QSFS (N) were 960 (LDGC_9), 1316 (LDGC_16), 3180 (YPSZ_9) and 3120 (YPSZ_16). For both QSFS and cyclic loading significant differences were found between LDGC_9 and LDGC_16 (p</=0.03) but not between YPSZ_9 and YPSZ_16 (p>0.05). Differences between LDGC and YPSZ were significant for both connector sizes (p</=0.001).

SIGNIFICANCE:

Considering the maximum chewing forces in the molar region it seems clinically possible, to use YPSZ as a core material for IRFPDs with a connector size between 9 and 16mm(2).

• Authors: Stefan Wolfart, Klaus Ludwig, Anja Uphaus, Matthias Kern
• Journal: Dental materials : official publication of the Academy of Dental Materials (Dent Mater) Vol. 23 Issue 12 Pg. 1513-20 (Dec 2007) ISSN: 0109-5641 [Print] England
• PMID: 17368743 (Publication Type: Comparative Study, Journal Article)

Chemical References

• Lithium Compounds
• Resin Cements
• yttria stabilized tetragonal zirconia
• Dental Porcelain
• Yttrium
• Glass ceramics
• Zirconium

Topics

• Bite Force
• Ceramics
• Computer-Aided Design
• Dental Porcelain (chemistry)
• Dental Stress Analysis
• Denture Design
• Denture Retention
• Denture, Partial, Fixed
• Inlays
• Lithium Compounds
• Materials Testing
• Models, Dental
• Molar
• Resin Cements
• Yttrium
• Zirconium