Premium
Effect of Aluminum Oxide Addition on the Flexural Strength and Thermal Diffusivity of Heat‐Polymerized Acrylic Resin
Author(s) -
Ellakwa Ayman E.,
Morsy Mohamed A.,
ElSheikh Ali M.
Publication year - 2008
Publication title -
journal of prosthodontics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.902
H-Index - 60
eISSN - 1532-849X
pISSN - 1059-941X
DOI - 10.1111/j.1532-849x.2008.00318.x
Subject(s) - flexural strength , acrylic resin , materials science , composite material , weibull modulus , flexural modulus , thermal diffusivity , crosshead , polymerization , distilled water , universal testing machine , ultimate tensile strength , polymer , chemistry , coating , physics , chromatography , quantum mechanics
Purpose: This work was undertaken to investigate the effect of adding from 5% to 20% by weight aluminum oxide powder on the flexural strength and thermal diffusivity of heat‐polymerized acrylic resin. Materials and Methods: Seventy‐five specimens of heat‐polymerized acrylic resin were fabricated. The specimens were divided into five groups (n = 15) coded A to E. Group A was the control group (i.e., unmodified acrylic resin specimens). The specimens of the remaining four groups were reinforced with aluminum oxide (Al 2 O 3 ) powder to achieve loadings of 5%, 10%, 15%, and 20% by weight. Specimens were stored in distilled water at 37°C for 1 week before flexural strength testing to failure (5 mm/min crosshead speed) in a universal testing machine. Results were analyzed by one‐way analysis of variance and post hoc Tukey paired group comparison tests ( p < 0.05). Weibull analysis was used to calculate the Weibull modulus, characteristic strength, and the required stress for 1% and 5% probabilities of failure. Cylindrical test specimens (5 specimens/group) containing an embedded thermocouple were used to determine thermal diffusivity over a physiologic temperature range (0 to 70°C). Results: The mean flexural strength values of the heat‐polymerized acrylic resin were (in MPa) 99.45, 119.92, 121.19, 130.08, and 127.60 for groups A, B, C, D, and E, respectively. The flexural strength increased significantly after incorporation of 10% Al 2 O 3 . The mean thermal diffusivity values of the heat‐polymerized acrylic resin (in m 2 /sec) were 6.8, 7.2, 8.0, 8.5, and 9.3 for groups A, B, C, D, and E, respectively. Thermal diffusivities of the composites were found to be significantly higher than the unmodified acrylic resin. Thermal diffusivity was found to increase in proportion to the weight percentage of alumina filler, which suggested that the proper distribution of alumina powders through the insulating polymer matrix might form a pathway for heat conduction. Conclusion: Al 2 O 3 fillers have potential as added components in denture bases to provide increased flexural strength and thermal diffusivity. Increasing the flexural strength and heat transfer characteristics of the acrylic resin base material could lead to more patient satisfaction.