The diametral tensile strengths of various composite resins.

The products exhibiting the greatest tensile strength values were those systems which provided measuring devices enabling the dentist to more accurately control the amounts of material to be mixed. Statistical analysis supported this finding; the means of the powder/liquid and paste/liquid systems formed a group that was significantly different from the five paste/paste systems. This indicates that accurate measurement of components could represent one important factor in the ultimate strength of a composite resin. There was no apparent correlation between average density and mean diametral tensile strength for the seven systems compared in this study.