Repair strength of hypoallergenic denture base materials

Hypoallergenic denture base materials are commonly used for patients with allergic reactions to polymethyl methacrylate (PMMA) denture base materials. The goal for repaired fractured dentures fabricated from hypoallergenic denture base materials is to restore the dentures to their original strength.

The purpose of this in vitro study was to investigate the flexural properties of 7 hypoallergenic denture base materials after repair compared with a conventional PMMA-based heat-polymerizing resin.

Specimens (n=5) of the following hypoallergenic denture base materials with differing polymerization modes: Eclipse base material, Luxene, Microbase, Polyan, Puran HC, Alldent Sinomer, and The.r.mo.Free, were repaired with Versyo.com as well as the respective repair systems for 4 of the tested materials. A heat-polymerized acrylic resin (Paladon 65) was repaired using autopolymerizing acrylic resin (Palapress), which served as the control. Flexural strengths (MPa) and flexural moduli (MPa) were assessed before and after repair of each material, according to ISO 1567. The data were analyzed with repeated measures 2-way and 3-way ANOVA, 1-way ANOVA, and Bonferroni-Dunn's multiple comparisons post hoc analysis, or with the paired t test (alpha=.05).

Flexural strengths and flexural moduli of both repair methods (repair according to manufacturer's instructions or repair with Versyo.com) for all materials were significantly lower than those of the intact specimens (P<.001). Alldent Sinomer and The.r.mo.Free repaired with Versyo.com showed flexural strengths comparable to the intact material. The flexural modulus of Puran HC, Alldent Sinomer, and The.r.mo.Free repaired with Versyo.com did not differ significantly from the original, nonrepaired material. No significant differences were noted between the flexural strength (P=.616) and the flexural modulus (P=.138) values regarding the 2 repair methods of the respective materials. None of the repaired hypoallergenic denture base materials demonstrated significantly higher flexural strengths than repaired Paladon 65. Flexural strengths of repaired Puran HC and Alldent Sinomer were significantly lower than those of repaired Paladon 65 specimens (P<.001). Flexural moduli of repaired Puran HC, Alldent Sinomer, and The.r.mo.Free showed a significant decrease compared to the repaired Paladon 65 specimens (P<.001). Eclipse and Luxene passed the flexural property requirements of ISO 1567 before and after repair.

No significant influence of the repair systems was found, but the flexural properties of the repaired materials differed significantly with respect to the tested acrylic resins.