Resin-based composite performance: are there some things we can't predict?
OBJECTIVE
The objective of this manuscript is to address the following questions: Why do direct dental composite restorative materials fail clinically? What tests may be appropriate for predicting clinical performance? Does in vitro testing correlate with clinical performance?


METHODS
The literature relating to the clinical and laboratory performance of dental composite restorative materials was reviewed. The main reasons for failure and replacement of dental composite restorations provided the guidance for identifying specific material's properties that were likely to have the greatest impact on clinical outcomes.


RESULTS
There are few examples of studies showing correlation between laboratory tests of physical or mechanical properties and clinical performance of dental composites. Evidence does exist to relate clinical wear to flexure strength, fracture toughness and degree of conversion of the polymer matrix. There is evidence relating marginal breakdown to fracture toughness. Despite the fact that little confirmatory evidence exists, there is the expectation that clinical fracture and wear relates to resistance to fatigue. Only minimal evidence exists to correlate marginal quality and bond strength in the laboratory with clinical performance of bonded dental composites.


CONCLUSIONS
The use of clinical trials to evaluate new dental composite formulations for their performance is expensive and time consuming, and it would be ideal to be able to predict clinical outcomes based on a single or multiple laboratory tests. However, though certain correlations exist, the overall clinical success of dental composites is multi-factorial and therefore is unlikely to be predicted accurately by even a battery of in vitro test methods.
Division of Biomaterials and Biomechanics, Department of Restorative Dentistry, Oregon Health & Science University, Portland, OR 97239, USA. ferracan@ohsu.edu
Jack L
JL
Ferracane
D003188:Composite Resins / Q000737:chemistry*; D019232:Dental Restoration Failure; D019554:Dental Restoration Wear; D003793:Dental Restoration, Permanent / Q000379:methods*; D003799:Dental Stress Analysis / Q000379:methods*; D006801:Humans; D008422:Materials Testing / Q000379:methods*; D013499:Surface Properties
D003188:Composite Resins