Clinical wear performance of eight experimental dental composites over three years determined by two measuring methods

The effect of matrix selection, filler composition, filler silanization, op erator variations, and test site (dental clinic) on the wear rate of eight composites were evaluated, The wear was measured on replicas using both a m icroscopic and a laser scanning measuring method. The average wear rate on contact-free surfaces was 9.2 +/- 4.2 mum/month with the microscopic measur ement and 8.5 +/- 3.7 mum/month with the laser scanner over the 36-month pe riod. The urethane-based composites performed significantly better than tho se which were bisGMA-based. Restorations placed at one dental clinic showed significantly lower initial wear. There was also a significant difference between the operators that was most pronounced during the first 6 months. T he other variable (filler composition and silane treatment) did not affect the wear rate significantly.