IADR Abstract Archives
Mechanical Properties of Dental Composites Modified by Incorporation of Fluorapatite Micro-rods
Objectives: To evaluate the effect of varying the ratio of glass to fluorapatite (FA) fillers on the key mechanical properties of highly filled experimental dental composites.
Methods: Experimental composites were formulated containing BisGMA/TEGDMA/BisEMA and barium aluminium silicate glass as the primary filler. Synthesised FA rod-like crystals and bundles were incorporated at 0 (FA0), 10 (FA10), 20 (FA20), 30 (FA30) and 40% (FA40) by mass, maintaining an overall filler content of 80%wt. TetricEvoCeram (TC) was used as a contemporary control. Two-body wear, Vickers Hardness (HV), Flexural strength (FS), Flexural modulus (FM) and Fracture Toughness (K1C) were measured. Quantitative analysis of wear volume was carried out using a noncontact profilometer. Scanning Electron Microscopy and Energy Dispersive X-ray Spectroscopy were used to analyse the wear and fracture surfaces. Statistical analysis was conducted using SPSS.
Results: All experimental composites showed similar wear resistance (p>0.05) and enhanced microhardness compared to TC (p<0.05). FA containing composites showed higher FM (p<0.05) and similar FS (p>0.05) to TC but lower FM and FS when compared to 0FA. There was a moderate linear correlation between FM and FS. 30FA and 40FA showed similar K1C to TC and 0FA (p>0.05), whereas 10FA and 20FA showed lower K1C when compared to the other groups (p<0.05). Increased fracture toughness for the higher FA containing groups was attributed to the rod morphology of the FA bridging cracks as evidenced by SEM imaging of the fractured surfaces.
Conclusions: Experimental composites were successfully produced incorporating FA as secondary filler. The addition of FA did not affect the key physical and mechanical properties when compared to the contemporary control. Coupled with previous observed short and long term fluoride release under acidic conditions these novel materials show a promising step towards a potential “smart” fluoride releasing dental composite.
Methods: Experimental composites were formulated containing BisGMA/TEGDMA/BisEMA and barium aluminium silicate glass as the primary filler. Synthesised FA rod-like crystals and bundles were incorporated at 0 (FA0), 10 (FA10), 20 (FA20), 30 (FA30) and 40% (FA40) by mass, maintaining an overall filler content of 80%wt. TetricEvoCeram (TC) was used as a contemporary control. Two-body wear, Vickers Hardness (HV), Flexural strength (FS), Flexural modulus (FM) and Fracture Toughness (K1C) were measured. Quantitative analysis of wear volume was carried out using a noncontact profilometer. Scanning Electron Microscopy and Energy Dispersive X-ray Spectroscopy were used to analyse the wear and fracture surfaces. Statistical analysis was conducted using SPSS.
Results: All experimental composites showed similar wear resistance (p>0.05) and enhanced microhardness compared to TC (p<0.05). FA containing composites showed higher FM (p<0.05) and similar FS (p>0.05) to TC but lower FM and FS when compared to 0FA. There was a moderate linear correlation between FM and FS. 30FA and 40FA showed similar K1C to TC and 0FA (p>0.05), whereas 10FA and 20FA showed lower K1C when compared to the other groups (p<0.05). Increased fracture toughness for the higher FA containing groups was attributed to the rod morphology of the FA bridging cracks as evidenced by SEM imaging of the fractured surfaces.
Conclusions: Experimental composites were successfully produced incorporating FA as secondary filler. The addition of FA did not affect the key physical and mechanical properties when compared to the contemporary control. Coupled with previous observed short and long term fluoride release under acidic conditions these novel materials show a promising step towards a potential “smart” fluoride releasing dental composite.