Hydroxyapatite reinforced polymer has many potential clinical applications like bone cement, dental implants, and coating of joint replacement prosthesis. The influence of incorporation of Hydroxyapatite with heat cured acrylic resin has not been tested before.
So the aims were to evaluate of concentration and the effect of incorporation of recently synthetic Hydroxyapatite from egg shell on dimensional accuracy, transverse strength, FTIR, and NMR of RESPAL NF heat cured acrylic denture base, with, and without relining, and biocompatibility test on rabbit.
Methods:
167 samples of heat cured acrylic resin (HCAR) were prepared, and divided into three groups; the 1st group (Control), the 2nd and 3rd groups with additives 2%, 5% of Hydroxyapatite.
The 2nd and 3rd groups were divided into two subgroups; {first: HCAR mixed with 2%, or 5% of Hydroxyapatite, and the second: HCAR relined with additives of 2% or 5% Hydroxyapatite}. The samples were tested after 48 hours (transverse strength, dimensional accuracy, residual monomer, FTIR, NMR, and biocompatibility tests, through implantation of samples in subcutaneous layer of the mandible of the local bred rabbit.
Results: Results showed significant differences, with increased transverse strength, no residual monomer release, no dimensional changes after adding Hydroxyapatite to (HCAR). FTIR, and NMR spectra of pure PMMA, and the PMMA with Hydroxyapatite extracted from egg shells showed no different in the peaks before, and after addition Hydroxyapatite to the polymer. Results of implantation samples showed increased bone formation.
Conclusions: After adding Hydroxyapatite to heat cured acrylic resin showed an increase in strength of denture base with high dimensional accuracy, good biocompatibility with new bone formation in both 2%, and 5% Hydroxyapatite. FTIR and NMR spectra of polymer without and with Hydroxyapatite showed homogeneous distribution which will improve the mechanical properties of heat cured acrylic resin.