Objective: To evaluate and to compare the wear resistance of a newly introduced flowable composite material with a conventional resin-based nano composite against natural teeth (enamel) and porcelain crowns.
Materials and methods: 24 composite discs for each of two systems, Bulk fill Flowable (BF) and Supreme Ultra (SU), were made to 11 mm in diameter and 3 mm in thickness. All discs were scanned using lab scanner to generate threedimensional (3D) virtual representations before undergoing the surface wear procedures. The discs for each material were divided into two subgroups (n=12/subgroup), one for testing with enamel and one for testing with porcelain. Each disc was then immersed in artificial saliva at 37°C and loaded into the testing apparatus to induce a simulated grinding force. Reciprocating, bi-directional movements were performed by the machine when the discs were opposing either enamel (human extracted teeth) or porcelain (porcelain crown duplicates of the extracted teeth) occlusal surfaces. All the discs were subjected to 105 newtons (10.7 kilograms) of force for 50000 bi-directional cycles during the griding test. Finally, after the surface wear tests were completed, each disc was scanned again using same lab scanner. The pretest and post-test scans for each disc were compared within the computer software and the calculated volume (μm3) of material wear was presented in root mean square (RMS). Independent-samples t-tests were used to analyze the data.
Results: Both materials demonstrated higher RMS values of surface volume wear when opposing porcelain than when opposing enamel, for both BF (mean [SD] = 140 [27] μm3 with porcelain versus mean [SD] = 137 [9] μm3 with enamel) and SU (mean [SD] = 135 [14] μm3 with porcelain versus mean [SD] = 120 [9] μm3 with enamel). There was a statistically significant difference between the two materials when tested against both teeth and porcelain (p<0.05).
Conclusion: The results suggest that: 1- porcelain crowns resulted in more composite material wear compared to enamel surfaces, 2- Supreme Ultra composite resin material exhibited less surface wear when compared to Bulk fill Flowable composite resin materials.
Resin based composite; Bulk fill Flowable; Supreme ultra; Wear resistance