Micro-abrasion study of some dental restorative materials and enamel

Inside the mouth, tooth wear is a very complex phenomenon that occurs due to physiological, pathological, oral hygiene and orthodontics causes. Abrasion is a type of tooth wear, which causes severe damage compared to attrition, abfraction and erosion wear modes that occur simultaneously; principally on occlusal area during close phase of mastication process when abrasive particles from different sources are located between tooth and tooth or tooth and dental composite contact, designated as three-body abrasion wear in Tribology. 'In vitro' wear tests were carried out for three different dental composite restorative base resins, using the Micro-scale TE 66 wear test machine that offers the possibility to reproduce micro-abrasive wear (three-body rolling wear). Two different slurries were used; distillate water and artificial saliva containing SiC abrasive particles, F 1200 4 mm. Three dental composites materials and human enamel were tested at 0.25N load applied, 0.1 m/s speed ball, 7.98m sliding distance and 22% of volume containing SiC, at room temperature. Lost volume and wear coefficient, k, were calculated. Scanning electron microscopic and atomic force microscopic images were obtained and wear scars were analysed in order to identify wear mechanisms, such as ploughing, cutting and microcraking. Also, brittle delamination was found only for human enamel.