Flexibility of experimental alumina/feldspar and SR ADORO dental composites

Abstract

Introduction: Flexure of a dental composite can be detrimental to the success of a restoration. Flexibility considerations are thus important when comparing dental materials to optimize the success of resin restorations. Aims and objectives: Flexibility of 5.6 x 18.0 x 2.0 mm3 experimental alumina/feldspar and SR ADORO® dental composites specimens were compared. It was hypothesized that alumina/ feldspar composites would be less flexible under a load than SR ADORO® composites and that the flexibility would decrease significantly as the feldspar content was increased. Methods: Alumina was chemically sintered or bonded with 40%, 50% and 60% feldspar mass, silanized and infiltrated with urethane dimethacrylate (UDMA) to prepare the alumina/feldspar dental restorative composite specimens. Three point bending tests were performed in the Instron 44® machine for flexural comparison to SR ADORO®. Results and conclusions: The alumina/feldspar specimens showed lower flexibility (mm displacement) than SR ADORO® (p<0.05). Accurate flexibility comparisons were performed with 5.6 x 18.0 x 2.0 mm3 specimens. Flexibility comparisons performed with 5.6 x 18.0 x 2.0 mm3 specimens indicated that experimental alumina/ feldspar dental composites may provide added marginal seal benefit. However confirmation via in vivo function of alumina/ feldspar dental composites is recommended.