OBJECTIVES: The aim of this study was to investigate the effects of erosion and toothbrush abrasion on different restorative materials and human enamel. METHODS: Human enamel and 5 kinds of tooth-colored restorative materials were used. The restorative materials included three composite resins (Filtek Silorane, Tetric EvoCeram, and Tetric EvoFlow), a polyacid-modified composite (Dyract Extra), and a conventional glass-ionomer cement (Ketac Fil Plus). For each type of the material, 40 specimens were prepared and embedded in ceramic moulds and divided into four groups (n=10): control group (C), erosion group (E), abrasion group (A), and erosion-abrasion group (EA). The specimens were subjected to six daily erosive attacks (groups E and EA; citric acid, pH 2.3, 1 min) and/or six abrasive attacks (groups A and EA; toothbrush abrasion, 100 strokes, 1 min), while the control specimens (group C) were maintained in artificial saliva. After 10-day treatment, the substance loss and surface changes were determined by surface profilometry and scanning electron microscopy. RESULTS: Human enamel presented higher substance loss when compared to restorative materials. Generally, combined erosion-abrasion (EA) caused the highest substance loss, followed by erosion, abrasion, and storage in artificial saliva. Composite resin presented highest durability under erosive and/or abrasive attacks. Enamel and restorative materials showed degradation in groups E and EA through SEM observation. CONCLUSIONS: Toothbrush abrasion has a synergistic effect with erosion on substance loss of human enamel, polyacid-modified composite and glass-ionomer cement. The acid- and abrasive-resistance of human enamel was lower compared to restorative materials.
OBJECTIVES: The aim of this study was to investigate the effects of erosion and toothbrush abrasion on different restorative materials and human enamel. METHODS:Human enamel and 5 kinds of tooth-colored restorative materials were used. The restorative materials included three composite resins (Filtek Silorane, TetricEvoCeram, and TetricEvoFlow), a polyacid-modified composite (Dyract Extra), and a conventional glass-ionomer cement (Ketac Fil Plus). For each type of the material, 40 specimens were prepared and embedded in ceramic moulds and divided into four groups (n=10): control group (C), erosion group (E), abrasion group (A), and erosion-abrasion group (EA). The specimens were subjected to six daily erosive attacks (groups E and EA; citric acid, pH 2.3, 1 min) and/or six abrasive attacks (groups A and EA; toothbrush abrasion, 100 strokes, 1 min), while the control specimens (group C) were maintained in artificial saliva. After 10-day treatment, the substance loss and surface changes were determined by surface profilometry and scanning electron microscopy. RESULTS:Human enamel presented higher substance loss when compared to restorative materials. Generally, combined erosion-abrasion (EA) caused the highest substance loss, followed by erosion, abrasion, and storage in artificial saliva. Composite resin presented highest durability under erosive and/or abrasive attacks. Enamel and restorative materials showed degradation in groups E and EA through SEM observation. CONCLUSIONS: Toothbrush abrasion has a synergistic effect with erosion on substance loss of human enamel, polyacid-modified composite and glass-ionomer cement. The acid- and abrasive-resistance of human enamel was lower compared to restorative materials.