EVALUATION THE EFFECT OF INCORPORATED HYDROXYAPATITE PREPARED FROM DRIED EGG SHELL ON SOME PROPERTIES OF RELINED DENTURE BASE

Abstract

Objective: Hydroxyapatite (HA) [Ca10(PO4)6(OH)2] was used in various biomedical fields such as dental material, bone substitute and hard tissue paste. Hydroxyapatite (HA) reinforced polymer have many potential clinical applications like bone cement, dental implants, coating of joint replacement prosthesis (Tham and Chow, 2010). So the aims were to determine the effect of incorporation of recently synthetized Hydroxyapatite from egg shell in different concentration on dimensional accuracy, transverse strength, FTIR of RESPAL NF heat cured acrylic denture base, with, and without relining, and biocompatibility test on rabbit. Materials and Methods: 171 samples of heat cured acrylic resin (HCAR) were prepared, and divided into five groups; the 1st group (Control) heat cured acrylic resin, the 2nd groups heat cured acrylic resin mixed with 2% of Hydroxyapatite (HA), the 3rd groups (HCAR) relined with 2% (HA), the 4th group (HCAR) mixed with 5% of Hydroxyapatite, and the 5th group (HCAR) relined with 5% of Hydroxyapatite. The samples were tested after 48 hours from preparation for (biocompatibility tests through implantation of samples in subcutaneous layer of the mandible of the local bred rabbit, FTIR test, microscopical examination of Hydroxyapatite, indentation hardness, transverse strength, water sorption and solubility, tensile strength, dimensional accuracy, residual monomer. Results: showed significant differences in the transverse strength, no residual monomer release, no dimensional changes after adding Hydroxyapatite to (HCAR). FTIR spectra of pure poly methyl methacrylate (PMMA), and the (PMMA) with Hydroxyapatite extracted from egg shells showed no difference in the peaks before, and after addition of 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 spectra of polymer with and without Hydroxyapatite showed homogeneous distribution which will improve the mechanical properties of heat cured acrylic resin.