Mechanical Properties of Moulded Specimens of Hydroxyapatite with Varying Particle Size Incorporated with Different Propolis Compositions

Abstract

Incorporating hydroxyapatite (HA) with propolis would be beneficial for dental applications, providing an alternative dental biomaterial. The propolis is a resinous substance produced by bees with antibacterial, antifungal and anti-inflammatory that increase its potential as a biomaterial. This study explores the mechanical properties of different particle sizes of HA; micro-HA (μ-HA) and nano-HA (n-HA) by incorporating different compositions of propolis from 2.5 wt.% to 10 wt.%. The materials were sieved for 15 min and mixed on the mixing glass using polybasic carboxylic acid as a binder to form a homogenize composite HA and propolis. The composites were moulded into a 5 mm × 5 mm moulded. The water absorption increased with the addition of propolis indicating that more porous and potentially less durable in an aqueous environment The mechanical properties show improvement of n-HA compared to μ-HA due to better particle interaction and bonding. However, the incorporation of propolis from 2.5 wt.% to 10 wt.% decreased the compressive strength from 4.3 MPa to 0.8 MPa, vickers hardness from 500 HV to 420 HV and shore hardness from 90.6 mN to 76.6 mN due to the lower density of propolis which resulted in high porosity of moulded specimen. Accordingly, the mechanical properties of HA_2.5 Propolis and HA_5.0Propolis are comparable to Mineral Trioxide Aggregate (MTA) thereby ensuring adequate mechanical stability and leveraging the antimicrobial properties of propolis.