Surface alterations in materials for occlusal devices subjected to simulated brushing with different solutions.

STATEMENT OF PROBLEM Daily brushing of occlusal devices with different cleaning solutions can compromise the surface roughness and microhardness of the materials, affecting their clinical performance and longevity.

Purpose

The purpose of this in vitro study was to evaluate the influence of simulated brushing with different solutions on the surface roughness and microhardness of materials used to fabricate occlusal devices. MATERIAL AND

Methods

A total of 180 cylindrical specimens (Ø6×3 mm) were fabricated and divided into 3 groups: milled polymethyl methacrylate (PMMA) blocks (M), three-dimensional (3D) printed resin (P), and microwave-polymerized acrylic resin (MW). The specimens were subjected to simulated brushing with 4 solutions (distilled water, neutral detergent, toothpaste, and brushing gel for cleaning acrylic resin pieces). Vickers microhardness and surface roughness were evaluated before and after brushing. Data were analyzed using a 3-way repeated-measures ANOVA, followed by the Tukey honestly significant difference (HSD) test (α=.05).

Results

Group M exhibited the highest microhardness values under all conditions. Microhardness remained stable after brushing in all groups, except for group P with toothpaste, which showed a significant reduction (P<.001). Toothpaste significantly reduced the roughness of all materials (P<.001). Group P also showed decreased roughness after brushing with the gel (P<.001), whereas Group MW showed a significant reduction in roughness after exposure to neutral detergent (P<.001).

Conclusions

Simulated brushing promoted changes in the surface roughness of tested materials. Toothpaste produced a statistically significant reduction in roughness for all materials, while neutral detergent promoted a reduction only in MW. Group P showed a significant reduction in microhardness and greater surface wear compared with toothpaste. Among the solutions tested, neutral detergent was the least aggressive method and did not significantly alter the properties of the tested resins.