Roughness of flowable composites after tooth brush abrasion

Objectives: The aim of study was to assess the influence of tooth brushing on the surface roughness of five different flowable composites. Methods: The following composites were used for the study: Filtek Supreme XT-Flow (3M Espe, A), Tetric-Flow (Ivoclar Vivadent, B), Venus-Flow (Heraeus Kulzer, C), X-Flow (Dentsply De Trey, D) and Grandio-Flow (VOCO, E). Eight specimens each were fabricated and the surface was polished using flexible Sof-Lex discs (3M Espe). At baseline, surface roughness was measured by optical profilometry (S8P, Mahr) and average roughness (Ra) was calculated. The polished surfaces were subjected to tooth brushing for one hour using Elmex toothpaste (GABA) and a powered tooth brush (Oral B Plaque Control). After brush-ing, profilometric roughness evaluation was repeated. Additionally two specimens of each material were examined qualitatively by scanning electron microscopy (PSEM 500, Philips). Results: There was a significant effect of the different composites (p = 0.005) and a signifi-cant general effect of brushing (p = 0.038) on surface roughness. There were significant inter-actions between the composites and tooth brushing (p = 0.032). At baseline, surface rough-ness varied considerably (Ra-values: 0.541 µm (B), 0.543 µm (A), 0.565 µm (C) and 0.639 µm (D) to 0.86 µm (E)). After brushing, three of the composites became rougher (Ra-values: 0.636 µm (B), 0.649 µm (A) and 0.889 (C)). Surface roughness of one flowable product was not affected by brushing (Ra = 0.849 (E)) and one flowable composite became slightly smoother (Ra = 0.551 µm (D)). SEM evaluation showed the presence of large grooves and a selective removal of resin matrix around the filler particles, depending on the individual materials. Conclusion: Tooth brushing can cause a roughing of the surfaces of flowable composites. With respect to surface quality, the use of these materials for class V restorations is questionable.