The effect of nanohydroxyapatite and silver nanoparticles on the microhardness and surface roughness of composite...

The aim of this study was to evaluate the effect of nanohydroxyapatite (nanoHAP) and silver nanoparticles (AgNPs) on the microhardness and surface roughness of composite resin. Fifty disc-shaped composite resin specimens (10 mm in diameter and 1.5 mm in height) were prepared in 5 groups (n = 10) as follows: group 1, composite resin (negative control); group 2, hand-spatulated composite resin (positive control); group 3, composite resin and nanoHAP (2 wt%); group 4, composite resin and AgNPs (1 wt%); group 5, composite resin, nanoHAP (2 wt%), and AgNPs (1 wt%). The microhardness and surface roughness of the specimens were measured using a Vickers microhardness tester and surface profilometer. Data analysis was performed using 1-way analysis of variance and a Tukey test (P < 0.05). The incorporation of 2 wt% nanoHAP or 2 wt% nanoHAP plus 1 wt% AgNPs did not affect the microhardness of the composite resin (P > 0.05). However, the incorporation of 1 wt% AgNPs alone had a statistically significant negative effect on the microhardness (P < 0.05). A significant increase in surface roughness was found for the composite resin containing 2 wt% nanoHAP (P < 0.05). However, the incorporation of 1 wt% AgNPs or 2 wt% nanoHAP plus 1 wt% AgNPs into the composite resin did not affect surface roughness (P > 0.05). The incorporation of nanoHAP and AgNPs (group 5) into the composite resin did not have a negative effect on the surface roughness and microhardness of the composite resin. The highest surface roughness was observed in specimens in group 3 (composite resin and nanoHAP) and the lowest microhardness was observed in group 4 (composite resin and AgNPs).