Pressure Transmission and Distribution Underneath Polyamide Denture Base Materials

Objectives: Polyamide is potentially an alternative denture-base to conventional PMMA due to its aesthetic, higher elasticity, and toxicological safety for patients. However, there is a limited knowledge about polyamide properties. This study aimed to examine the pressure transmission and distribution underneath polyamide denture base materials (Valplast, Deflex, and Vertex Thermosens) compared to conventional heat cured PMMA (Pegasus Plus), and to evaluate their flexural modulus.
Methods: Flexural modulus was measured with a universal test machine (Instron 5567; Instron limited, England) using 70x10x3.50.05mm bar-shaped specimens (n=5). Pressure transmission and distribution were measured using the same machine fitted with a 4.6mm in diameter metal indenter to apply 400N force to the specimens. A mandibular first lower molar was embedded in a 1.5x1.5x3±0.05mm denture base following each manufacturer’s instructions (n=5) and stored in distilled water at 37°C for 24 hours before testing. Pressure transmission and distribution were measured using pressure-sensitive sheets (Prescale pressure measurement film, Fuji Film, Japan) placed underneath the specimens and then scanned using a scanner (Perfection V600, Epson, Japan) and interpreted using pressure distribution mapping system software (FPD 8010E, Fuji Film, Japan). Flexural modulus, and pressure transmission and distribution, were analysed with ANOVA followed by Tukey post-hoc test (P=0.05).
Results: All polyamide materials flexural modulus were significantly lower than PMMA (P<0.01), where Valplast were the lowest among all tested materials. The pressed area of all polyamide denture base materials was significantly lower than PMMA (P<0.01), while the load transferred by the materials were significantly different (P<0.01). Regarding the pressure transmission and distribution, Valplast were significantly higher compared to other materials (P<0.01).
Conclusions: Denture base with low modulus of elasticity tends to transmit higher force which can lead to pain and residual ridge resorption. Clinicians should consider the properties of denture base in making the treatment plan of the patients.