Comparison between the effect of adding microhydroxyapatite and chitosan on surface roughness and Microhardness of resin modified and conventional glass ionomer cements.

BACKGROUND

This study aimed to compare the effect of chitosan (CH) and hydroxyapatite (HP) on the surface roughness and microhardness of a conventional glass ionomer cement (CGIC) and a resin modified glass ionomer cement (RMGIC).

MATERIAL AND METHODS

60 disk-shaped specimens (2mm x 6mm) were prepared in 6 groups; group I: CGIC, group II: RMGIC, group III: CGIC + 15% volume CH solution in liquid, group IV: CGIC +10% weight micro-HP in powder, group V: RMGIC + 15% volume CH, group VI: RMGIC + 10% weight micro-HP. After storage in deionized water at room temperature for 24 hours, the surface roughness and microhardness of the specimens were measured using a surface profilometer and Vickers microhardness (VHN) tester, respectively. Data were analyzed using two-way ANOVA, Tukey HSD test and paired t-test (<0.05).

RESULTS

The microhardness values of RMGIC and CGIC decreased significantly with the addition of micro-HP (<0.001). None of the CH-containing GICs showed significant changes in microhardness ( = 0.552). The VHN values of CGIC were higher than RMGIC, regardless of the added substance (<0.001). The surface roughness (Ra) values (μm) of both RMGIC and CGIC decreased significantly with the addition of CH ( = 0.004). The incorporation of micro-HP into GICs did not have a significant effect on surface roughness values ( = 0.700). The RMGIC showed less Ra values compared to the CGIC regardless of the added substance (<0.001). The lowest and highest Ra values were observed in RMGIC + CH and CGIC + micro-HP groups, respectively.

CONCLUSIONS

The addition of CH to GIC and RMGIC reduced the surface roughness and did not have an adverse effect on the microhardness. Mixing GIC and RMGIC with micro-HP resulted in microhardness reduction and did not affect the surface roughness. Glass ionomer, hydroxyapatite, chitosan, hardness, surface roughness.