Influence of an experimental palatal plate on thermal perception

Evaluation of thermal conductivity and flexural strength properties of poly(methyl methacrylate) denture base material reinforced with different fillers

STATEMENT OF PROBLEM

Poly(methyl methacrylate) (PMMA) is widely used in prosthodontics as a denture base material. However, it has several disadvantages, including low strength and low thermal conductivity.

PURPOSE

The purpose of this in vitro study was to evaluate thermal conductivity and flexural strength after adding powdered Ag, TiO₂, ZrO₂, Al₂O₃, SiC, SiC-nano, Si₃N₄, and HA-nano in ratios of 10 wt% to PMMA.

MATERIAL AND METHODS

A total of 144 specimens were fabricated and divided into 18 groups. Specimens were left in water for 30 days. Thermal conductivity values were measured using a heat flowmeter, flexural strength was measured with a 3-point bend test, and specimens were investigated with environmental scanning electron microscopy. One-way ANOVA was used to compare means followed by using Duncan multiple range test (α=.05).

RESULTS

The thermal conductivity value of PMMA increased significantly after the addition of Si₃N₄, SiC, Al₂O₃, SiC-nano, TiO₂, ZrO₂, HA-nano, and Ag. Progressive increases in thermal conductivity were observed in Si₃N₄, SiC, and Al₂O₃ fillers. Flexural strength values of the control group were not significantly different from those of the SiC, Al₂O₃, or Ag group (P>.05). In the other groups, flexural strength values decreased significantly (P<.05). On the basis of electron microscopy, we observed that Si₃N₄, SiC, and Al₂O₃ powders had higher thermal conductivity values that are dissipated more homogeneously in PMMA.

CONCLUSIONS

Although the addition of 10 wt% SiC, Al₂O_3, and Ag powder to PMMA significantly increased thermal conductivity, the flexural strength values of PMMA were not significantly changed.