Physical properties of acrylic resin teeth submitted to toothbrushing and immersion in beverages

Abstract

Background: Brushing and consumption of dye beverages may alter the physical properties of artificial teeth. Objective: The objective of this study was to evaluate the effect of toothbrushing and immersion in beverages in roughness and color of two types of artificial teeth: Biotone (B) and Biotone interpenetrating polymer network (IPN). Materials and Methods: For each tooth, seven groups were formed (n = 10): Toothbrushing (T), toothbrushing + water (TW), toothbrushing + coke (TCk), toothbrushing + coffee (TCf ), immersion in water (W), coke (Ck), coffee (Cf ). Roughness and color stability evaluations were performed before treatment and after treatment. According to the group, 11,000 brushing cycles were performed and specimens were immersed in beverages for 12 days, both simulating a period of 1 year. Color variations were captured by a spectrophotometer and roughness was analyzed by a profilometer. Color data were analyzed using analysis of variance (ANOVA) and Least significant difference test whereas roughness data were analyzed using ANOVA and Bonferroni test, both with α =0.05. Results: For Biotone, clinical significant color changes according to National Bureau of Standards (NBS) units were observed for the Groups T, TW, W, and Ck, and the results of ΔE were statistically similar among them (P > 0.05). For Biotone IPN, clinical significant color changes were found for TCf (4.86 NBS units) and Cf (4.82), and the results of ΔE were also similar among them. Surface roughness Ra (µm), regardless of the teeth, was reduced for the groups submitted to toothbrushing whereas no significant differences were found among the Groups W, Ck, and Cf. Conclusions: Toothbrushing had no influence on the color stability but significantly reduced the roughness, irrespective of the type of tooth.

In Vitro Effect of Acidic Challenges on the Physical Properties of Dental Prosthesis Artificial Teeth

“…These factors favor the crosslinking quality of polymer chains, improving its mechanical properties and reducing the tendency to form pre-cracks under masticatory stresses and the solubility in organic solvents [26]. Biotone artificial teeth are also composed by PMMA chains, but they have low molecular weight [8] and two layers of acrylic teeth (body and enamel), according to the manufacturer. This composition of Biotone group can also have contributed to low color stability, as also found in other study [18].…”

“…These results indicate that the effects of longer exposure times to acidic beverages on the surface roughness of acrylic artificial teeth should be further investigated. Additionally, a previous study [8] evaluated the roughness surface of artificial acrylic resin teeth before and after soaking in cola drink. There was only difference in Ra values where the abrasion by toothbrushing was performed before the immersion in cola drink.…”

“…Thus, the toothbrushing may have acted as an abrasive factor on acrylic teeth surface, making them less irregular and influencing the surface roughness [8,30].…”

“…The acrylic resin artificial teeth are widely used in dentures due to the easy occlusal adjustment, lower fractures propensity compared to ceramic, excellent chemical bonding with the base of the prosthesis and adequate absorption of masticatory forces [4,[6][7][8].…”

“…The effect of beverages on the artificial teeth may change the hardness and the roughness surface and interfere on the accumulation of biofilm and on the optical properties of the material, affecting the quality of the prothesis over years [7,9,12,13]. However, the type of acid beverage, the exposure time and the corrosive challenge with the beverage can affect differently the physical properties of acrylic resin teeth surface [4,[7][8][9]. Thus, the present in vitro study aimed to evaluate the effect of immersion and acid challenge with cola drink on color change (ΔE), Vickers hardness (VHN) and surface roughness (Ra) of artificial acrylic resin teeth.…”