Effect of 2% Sodium Hypochlorite, Denture Cleansing Tablet and Tea on the Discolouration and Surface Roughness on Two Types of Denture Acrylic Resin: An In-vitro Study

Introduction: Denture cleansers affect the physical properties of denture materials, such as colour and surface roughness. Using denture cleanser with the least side-effects in the best choice. There are only limited studies available evaluating the effects of denture cleaners in association with staining solutions on acrylic resins. Aim: This study aimed to investigate the effect of denture cleansers in association with staining solution (tea), on the denture colour and surface roughness. Materials and Methods: In this in-vitro study conducted at dentistry faculty of Tabriz medical university of science, Tabriz, East Azarbaijan, Iran, from May 2018 to June 2019, 56 samples were prepared from two types of acrylic resin ( Acrosun and TDV Dental). The 2% Sodium Hypochlorite (NaOCl) solution and professional cleansing tablets were used as detergents, and tea was used as a dye. The samples were assigned to seven groups (n=8 samples in each group) for each type of acrylic used. The study groups consisted of group 1 (NaOCl solution for 10 minutes), group 2 (NaOCl solution for 8 hours), group 3 (cleansing tablet solution for 8 hours), group 4 (tea solution for 2 hours), group 5 (first tea solution and then NaOCl), group 6 (tea solution and then cleansing tablets) and group 7 (distilled water). Surface roughness was analysed with Ra and Rz indices, and colour changes were evaluated with CIELAB index before and after the experiment, and the data were recorded. Finally, data analysis was performed with Statistical Package for the Social Sciences (SPSS) version 21.0. The p-value less than 0.05 was considered as significant. Results: The results showed that in all the study groups, the colour change of Acrosun acrylic resin was more severe compared to that in TDV dental acrylic resin, which was significant only in groups 1, 2, and 5 (p-value<0.05). Comparison of the mean Ra index showed that surface roughness was the maximum and minimum in groups 6 and 1, respectively, compared to other groups. A comparison of the effect of different cleaning methods on acrylic resin surface roughness showed that the surface roughness indices of Ra and Rz were not significantly different in any of the groups ( p-value>0.05). Conclusion: The two types of acrylic resin did not differ significantly in surface roughness after the experiments. However, the TDV dental acrylic resin was superior in terms of colour stability.