Influence of beverage solutions on the microhardness and surface roughness of provisional fixed denture materials

This in vitro study examined the influence of aging in different beverage solutions on the Knoop hardness and surface roughness of provisional fixed denture materials. A total of 160 resin blocks were created and divided into 4 groups (n = 40) based on the provisional material: Structur 2 SC bis-acrylic resin, Protemp 4 bis-acrylic resin, Z350 XT nanoparticle composite resin, or Acri Duralay acrylic resin. The material groups were subdivided into 4 groups (n = 10) according to the beverage solution used to simulate aging: distilled water (control), red wine, orange juice, or soda (Coca-Cola). After 24 hours, the specimens were polished, and the initial microhardness and surface roughness were measured using a microhardness tester and profilometer, respectively. The specimens were then submerged in different beverage solutions for 4 weeks, and microhardness and surface roughness measurements were taken again. Two-way repeated-measures analysis of variance and Fisher least significant difference test were performed (α = 0.05). The aging process with different beverage solutions resulted in significantly lower hardness values compared with baseline for both Z350 XT and Acri Duralay materials (P < 0.05); however, Z350 XT still demonstrated significantly higher hardness values than all other materials regardless of the aging condition (P < 0.05). In general, Protemp 4 and Z350 XT exhibited lower surface roughness values than Structur 2 SC and Acri Duralay regardless of the solution used (P < 0.05). Beverage solutions significantly influenced the mechanical properties of the materials, with Protemp 4 bis-acryl-based resin material demonstrating hardness and surface roughness values that were less affected by aging.