Structure and Properties of Dental Resin Composites containing Tricalcium Phosphate and Hydroxyapatite Fillers

Access to files

•   FULL-TEXT.PDF (pdf)

Abstract

Objective: The purpose of this study was to correlate the structure of beta Tricalcium phosphate(β-TCP) and hydroxyapatite (HAP) with the key properties of the experimental resin compositesMethods: β-TCP and three types of HAP powders labelled as A, B and C were examined under SEM to study their morphology. The particle size was measured using a laser diffraction particle size analyser. These fillers were used to prepare the experimental resin composites. The matrix was composed of a visible light-cured monomer urethane dimethacrylate (UDMA). Five resin composites from each type of filler were prepared by varying filler loading ratio from 20 to 60 % by weight.The properties studied for each resin composite were Vickers hardness, Surface gloss and Surface roughness. Vickers hardness (VHN) was evaluated immediately and after dry storage at 37 oC for 24h. Surface gloss and roughness (Ra, Rt) of each resin composite were evaluated before polishing, after polishing, and after toothbrush abrasion. Mean values and standard deviations were analysed by two way (ANOVA) (P<0.05) followed by Tukey`s post hoc test for multiple comparisons.Results: The SEM and particle size analysis indicated that β-TCP fillers were composed of rods with an average diameter of 10 µm. The HAP fillers labelled as types A and B were spherical with an average diameter of 3-4 µm. Type C HAP consisted of rough, irregular micro-sized particles with an average diameter of 10-100µm.The VHN values of all the resin composites increased significantly after dry storage at 37 oC for 24h after curing. Β-TCP containing resin composites exhibited highest VHN values which were directly correlated with their filler content. Whereas, the VHN values of the HAP containing resin composites increased as the filler content increased and then remained constant or decreased with further increase in filler content.Surface gloss decreased significantly for all of the resin composites after polishing and after toothbrush abrasion. The gloss values of all the resin composites decreased as the filler content increased. β-TCP presented with highest gloss whereas Type C HAP presented with lowest gloss values.Surface roughness increased significantly after polishing and after toothbrush abrasion for all the four types of resin composites. However, different trends in the roughness parameters were observed as the filler content was increased. Surface roughness of β- TCP containing resin composites decreased after polishing and after toothbrush abrasion as the filler content increased. Among the resin composites containing HAP fillers, types A and B surface roughness did not change significantly as the filler content increased, whereas Type C presented with highest surface roughness which was directly correlated with their filler content.Conclusion: By modifying the filler content of resin composites and varying the crystal size and shape characteristics of the inorganic filler, the properties of resin composite could be modified

Layman's Abstract

Objective: The purpose of this study was to correlate the structure of beta Tricalcium phosphate(β-TCP) and hydroxyapatite (HAP) with the key properties of the experimental resin compositesMethods: β-TCP and three types of HAP powders labelled as A, B and C were examined under SEM to study their morphology. The particle size was measured using a laser diffraction particle size analyser. These fillers were used to prepare the experimental resin composites. The matrix was composed of a visible light-cured monomer urethane dimethacrylate (UDMA). Five resin composites from each type of filler were prepared by varying filler loading ratio from 20 to 60 % by weight.The properties studied for each resin composite were Vickers hardness, Surface gloss and Surface roughness. Vickers hardness (VHN) was evaluated immediately and after dry storage at 37 oC for 24h. Surface gloss and roughness (Ra, Rt) of each resin composite were evaluated before polishing, after polishing, and after toothbrush abrasion. Mean values and standard deviations were analysed by two way (ANOVA) (P<0.05) followed by Tukey`s post hoc test for multiple comparisons.Results: The SEM and particle size analysis indicated that β-TCP fillers were composed of rods with an average diameter of 10 µm. The HAP fillers labelled as types A and B were spherical with an average diameter of 3-4 µm. Type C HAP consisted of rough, irregular micro-sized particles with an average diameter of 10-100µm.The VHN values of all the resin composites increased significantly after dry storage at 37 oC for 24h after curing. Β-TCP containing resin composites exhibited highest VHN values which were directly correlated with their filler content. Whereas, the VHN values of the HAP containing resin composites increased as the filler content increased and then remained constant or decreased with further increase in filler content.Surface gloss decreased significantly for all of the resin composites after polishing and after toothbrush abrasion. The gloss values of all the resin composites decreased as the filler content increased. β-TCP presented with highest gloss whereas Type C HAP presented with lowest gloss values.Surface roughness increased significantly after polishing and after toothbrush abrasion for all the four types of resin composites. However, different trends in the roughness parameters were observed as the filler content was increased. Surface roughness of β- TCP containing resin composites decreased after polishing and after toothbrush abrasion as the filler content increased. Among the resin composites containing HAP fillers, types A and B surface roughness did not change significantly as the filler content increased, whereas Type C presented with highest surface roughness which was directly correlated with their filler content.Conclusion: By modifying the filler content of resin composites and varying the crystal size and shape characteristics of the inorganic filler, the properties of resin composite could be modified

Keyword(s)

resin composites, hydroxyapatite, tricalcium phoshate

Bibliographic metadata

Institutional metadata

Record metadata