Effect of Denture Cleanser on the Physico-Mechanical Properties of Injection-Molded Thermoplastic Polyamides Denture Base Material: A preliminary Study

OBJECTIVES: This study aimed to assess the color stability, surface roughness, and flexural properties of the injection-molded thermoplastic polyamide Vertex ThermoSens denture base resin following a 3-minute immersion in Polident 3-minute denture cleanser.

METHODS: Sixty specimens (Vertex ThermoSens) were processed and divided into two main groups (n = 30) based on the type of test. Group 1 was further subdivided into two subgroups (n = 15): the control group immersed in distilled water (G1DW) and the test group immersed in Polident cleanser solution (G1PD). Group 2 was divided into three subgroups: a non-immersed group (G2None), a group immersed in distilled water (G2DW), and a group immersed in Polident cleanser solution (G2PD). Color change (∆E) and surface roughness measurements were conducted for group 1, and flexural modulus (E) test was performed for group 2. The CIE Lab* formula was utilized to calculate ∆E. An optical 3D surface analyzer and a three-point bending test were employed for surface roughness and E assessments, respectively. Data were subjected to statistical analysis using a paired-sample t-test for differences within each group before and after immersion. Furthermore, independent-sample t-tests and one-way ANOVA were conducted to analyze differences between groups. A significance level of P < 0.05 was considered.

RESULTS: The results revealed a slight, statistically insignificant (P > 0.05) ∆E in all color components (L*, a*, b*) after immersion in distilled water. However, after immersion in the denture cleanser, only the L* component exhibited a statistically significant ∆E (P = 0.002), which was slight in magnitude. Additionally, a significant difference was found in the ∆E between G1DW and G1PD, with G1PD showing a higher change (P = 0.007). A significant increase in surface roughness after immersion was observed in G1PD (P = 0.017), with a notable difference between G1DW and G1PD. However, the E remained unaffected (P = 0.537).

CONCLUSION: Denture cleansers have the potential to modify the properties of thermoplastic polyamide resin. Further research is needed to explore the clinical implications of these observed changes on denture performance.