J Contemp Dent Pract. 2026 Feb 1;27(2):141-147. doi: 10.5005/jp-journals-10024-4033.
ABSTRACT
AIM: This study investigated the effect of adding bioactive biocompatible seashell-derived hydroxyapatite (HA) nanofillers on the mechanical properties of acrylic polymethyl methacrylate (PMMA) resin, namely flexural strength, hardness, and compressive strength.
MATERIALS AND METHODS: Sixty acrylic specimens were divided into four groups, with five acrylic specimens for each test; control and experimental specimens containing 5, 10, and 12% seashell nanoparticles (NPs) added to the acrylic. The tests included hardness, compression strength, and flexural strength. According to the required proportion of NPs, these NPs were added to the monomer (liquid) of the cold-cured acrylic resin. The specimens were removed to complete the preparation process and then stored in distilled water at 37°C for 48 hours before testing. Data were analyzed using SPSS software. The difference was considered statistically significant at a p-value ≤ 0.05. For descriptive analysis of all variables, a paired t-test was used to compare the control group with the experimental groups.
RESULTS: For hardness and compression strength, the highest mean values for the groups were 12, 10, and 5%, respectively. For flexural strength, the 12% group was higher than the control group, followed by the 10% group, and then the 5% group, which was lower than the control group. A significant difference was found between the control group at both 5 and 12% for flexural strength, and a significant difference was also found between the control group at both 5 and 10% for hardness, and across all concentration groups for compression.
CONCLUSION: Adding a high concentration of seashell HA NP largely increased the flexural strength of PMMA resin. Cold-cured PMMA resin incorporated with lower concentrations of seashell HA NPs noticeably revealed improved hardness. Seashell HA NPs at the studied three concentrations improved the compression strength of the cold-cured PMMA resin.
CLINICAL SIGNIFICANCE: Natural HA NPs from seashell can be used as a bio-compatible nanofiller that can strengthen self-curing polymer materials. How to cite this article: Al Hamdany AK, Tawfek ZS, Agha NF, et al. Effect of Hydroxyapatite Seashell Nanofiller on Some Properties of Autopolymerized Acrylic Material for Orthodontic Appliances. J Contemp Dent Pract 2026;27(2):141-147.
PMID:42145162 | DOI:10.5005/jp-journals-10024-4033
