Objective. The aim of this in vitro study was to evaluate the surface roughness of human enamel bleached with 10% carbamide peroxide or 10% hydrogen peroxide bleaching agents at different times and also subjected to different superficial cleaning treatments. Materials and methods. One hundred and forty flat enamel samples were divided into 14 groups, Group 1–Group 14 (G1–G14). G1–G7 were treated with 10% carbamide peroxide and different dentifrices, G8–G14 were treated with 10% hydrogen peroxide and different dentifrices (G1 and G8: not brushed as control groups; G2 and G9: brushed with Ipana® toothpaste; G3 and G10: brushed with Clinomyn® toothpaste; G4 and G11: brushed with Moos Dent® toothpaste; G5 and G12: brushed with Signal® toothpaste; G6 and G13: brushed with Colgate® toothpaste; G7 and G14: brushed without dentifrice). A profilometer was used to measure average roughness values of the initial surface roughness and at each 7-day-interval. The bleaching was performed for 6 h a day and the surface cleaning treatment was performed 3-times a day, 2 min each time, for 4 weeks. The samples were stored in distilled water during the test period. Results. Statistical analysis revealed significant differences in surface roughness values over time for all groups except G1 and G8 (not brushed). The results of the surface roughness of all groups were nearly the same. Conclusions. The bleaching with 10% hydrogen peroxide and 10% carbamide peroxide did not alter the enamel surface roughness, but when the bleaching treatment was performed combined with abrasive dentifrices, a significant increase in roughness values was observed.

Purpose: This study evaluated the microhardness and surface roughness of four artificial teeth type against various beverages. Materials and Methods: Conventional acrylic resin, reinforced acrylic resin, microfiller composite resin, and nanofiller composite resin teeth were used. From each group, 10 maxillary first and second molars were immersed in 5 beverages (tea, filtered coffee, cola, cherry juice, and distilled water. The test period of 24 hours appears comparable to approximately 1 month of normal beverage consumption. The test periods used in this study were arranged according to this protocol and 1 week, 1 month, 3 months and 6 months of normal beverage consumptions were simulated. Vickers microhardness and surface roughness of denture teeth were measured for each test period. Results: The microhardness values significantly decreased in all beverages especially in 6th month. The surface roughness values significantly increased in all beverages especially in 3th month. There were no statistically significant differences between the beverages. Microfiller composite resin denture teeth had the highest microhardness values and the lowest surface roughness values. Conclusions: Different types of beverages consumed daily negatively affect the microhardness and surface roughness of artificial teeth. Microfiller composite resin teeth could have the ideal surface properties

Aim: New types of denture teeth using modified acrylic resin that incorporate cross-linking agents and composite resin containing different types of filler have become increasingly common. It has been possible to produce nano-sized filler particles with nanotechnology. However, evidence-based information regarding composition and properties is lacking. The purpose of this study was to evaluate the colour stability of four commercially available denture tooth materials with different chemical structure when subjected to various beverages. Methods: Conventional acrylic resin, reinforced acrylic resin, microfiller composite resin, and nanofiller composite resin teeth with different brands were used, for a total of four different denture teeth groups. Denture teeth were subjected to four beverages (tea, filtered coffee, cola, and cherry juice) and distilled water as control. The test period of 24 hours appears comparable to approximately 1 month of normal beverage consumption. The test periods used in this study were arranged according to this protocol and 1 week, 1 month, 3 months and 6 months of normal beverage consumptions were simulated. From each group, 10 maxillary first molar denture teeth were immersed in each of the five solutions. The baseline, 1st week, 1st month, 3rd month and 6th month values for colour change of denture teeth were measured. Results: The differences of each value were calculated by one-way ANOVA statistically. For colour changes (ΔE) there was no significant difference among the specimens immersed in distilled water (Tukey HSD test, p>0.01). The highest colour changes were recorded for the specimens of Integral and Major immersed in cola, whereas for the specimens of Veracia and Orthosit immersed in tea (Tukey HSD test, p<0.01). Conclusions: Within the limitations of this study, daily intake of common beverages may lead to colour changes of denture teeth. Microfiller composite resin denture tooth material is recommended due to its improved physical properties.