Effect of Toothbrushing Abrasion on Surface Roughness and Gloss Retention of Nanocomposite Denture Teeth Materials
Abstract
Objectives :This study evaluated the comparative effect of simulated toothbrushing abrasion on the surface roughness (Ra) and gloss retention of nanocomposite, microfilled composite, and conventional polymethyl methacrylate (PMMA) artificial denture teeth.
Materials and Methods:Sixty artificial maxillary central incisor denture teeth were divided into three groups (n=20 each) based on their material composition: Group 1 (Nanocomposite; Veracia SA), Group 2 (Microfilled composite; SR Phonares II), and Group 3 (Conventional PMMA; Major Dent). The specimens were embedded in acrylic resin blocks and polished to achieve flat, uniform baseline surfaces. Simulated toothbrushing abrasion was performed using a mechanical brushing simulator with a standard dentifrice slurry under a 200 g vertical load. Profilometric surface roughness (Ra, μm) and gloss units (GU, measured at a 60° geometry) were recorded at baseline (T 0 ), after 10,000 brushing cycles (T 1 ), and after 20,000 brushing cycles (T 2 ). Data were analyzed using two-way repeated measures ANOVA and Tukey’s post-hoc tests (α=0.05).
Results :Toothbrushing abrasion significantly increased surface roughness and decreased gloss across all groups (p<0.001). At T 2 (20,000 cycles), Group 3 (PMMA) exhibited the highest surface roughness (0.48±0.04 μm) and lowest gloss retention (42.3±3.1 GU). Group 1 (Nanocomposite) demonstrated the lowest surface roughness (0.23±0.02 μm) and highest gloss retention (76.8±2.4 GU) at T 2 , followed by Group 2 (0.31±0.03 μm; 61.5±2.9 GU). The differences between all groups at T 1 and T 2 were statistically significant (p<0.05).
Conclusion:Nanocomposite denture teeth demonstrate superior resistance to toothbrushing abrasion, maintaining lower surface roughness and higher gloss retention over simulated clinical timelines compared to microfilled composite and conventional PMMA teeth.
References
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