Fracture load of fixed partial dentures anchored by composite inlays.
OBJECTIVE
To evaluate in vitro the fracture load of fixed partial dentures (FPDs) anchored by use of composite inlays. The effects of span length, silica-coating, mechanical loading and framework material were also tested.


METHODS
Defined box inlay cavities were made on a mandibular molar and a premolar. Fifty-six FPDs were manufactured using a polymer composite material and received an industrial prefabricated polymethylmethacrylate (PMMA) frame for stabilization. All FPDs underwent thermal cycling. The FPDs were divided into test groups simulating the effect of different span length (7 or 12 mm), tribochemically silicoating (yes or no) and mechanical loading (yes or no). The load to fracture was measured and fracture sites were evaluated. As a control group for the PMMA frame, a metal alloy frame was used, and evaluated under the most unfavorable conditions. The Mann-Whitney U-test followed by the Bonferroni correction was used for statistical analysis.


RESULTS
The span length significantly affected the fracture load. Values ranged from 413 N for the 12 mm span length to 706 N for the 7 mm span length. Thermal cycling and mechanical loading significantly reduced fracture load values for FPDs with the 12 mm span length, but there were no significant effects for FPDs with 7 mm span length. Silicoating pretreatment of the metal abutments significantly reduced fracture load values. Replacement of the PMMA frame with a metal frame increased fracture load values up to 1,075 N.
Ohlmann
Brigitte M
BM
Department of Prosthodontics MZK II, University of Heidelberg, Im Neuenheimer Feld 400, 69120 Heidelberg, Germany. Brigitte_Ohlmann@med.uni-heidelberg.de
Schmitter
Marc
M
Gabbert
Olaf
O
Rammelsberg
Peter
P
D001641:Bicuspid; D003188:Composite Resins / Q000737:chemistry*; D000044:Dental Abutments; D003722:Dental Alloys / Q000737:chemistry; D001840:Dental Bonding; D003737:Dental Cavity Preparation / Q000379:methods; D003738:Dental Cements / Q000737:chemistry; D017267:Dental Prosthesis Design; D019232:Dental Restoration Failure; D003779:Denture Design; D003830:Denture, Partial, Fixed; D006801:Humans; D007284:Inlays; D008422:Materials Testing; D008963:Molar; D019904:Polymethyl Methacrylate / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D013696:Temperature
D003188:Composite Resins; D003722:Dental Alloys; D003738:Dental Cements; D019279:Resin Cements; C076811:Rocatec; D012822:Silicon Dioxide; D019904:Polymethyl Methacrylate