Characterization of limestone-based beta-tricalcium phosphate /polyacrylic acid blocks as bone graft candidates

Abstract

Background: Bone grafting is a widely used technique in dentistry to repair bone defects. Limestone-based beta-tricalcium phosphate (β-TCP) holds potential as an alternative bone graft material when combined with polyacrylic acid (PAA) to produce composite blocks. Purpose: The aim of the study was to evaluate the characteristics, including porosity, diametral tensile strength (DTS), morphology, macropore size, and micropore size of block composites made from limestone-based β-TCP and PAA as well as the effect of their composition on these characteristics. Methods: This was a laboratory experimental study employing a post-test-only control group design. The study groups consisted of a negative control (pure PAA powder), a positive control (PAA + commercial β-TCP), and three treatment groups with variations in the mixture of limestone β-TCP and PAA: 60:40, 50:50, and 40:60 (%w/w). The samples were characterized for porosity using volume and weight measurements, for DTS using a universal testing machine, and for morphology using scanning electron microscopy. Results: Limestone-based β-TCP produced composites with higher porosity and DTS compared to pure PAA samples and commercial β-TCP. Increasing the β-TCP content generally increased porosity and DTS, although porosity decreased in the 40:60 group. The composite blocks predominantly exhibited closed porosity, with macropore size ranging from 81.30 µm to 198.40 µm. Conclusion: Increasing the proportion of limestone-based β-TCP results in higher porosity and DTS values than commercial β-TCP, partly due to particle size contributing to higher values. The composite blocks are porous, while pure PAA has a smooth, pore-free surface. However, further optimization is still required.