Effects of different implant materials and surface microgrooves on the biological behavior of gingival fibroblasts

Abstract

Objective: To study the effect of microgroove surface modification of titanium and zirconia on the biological behavior of gingival fibroblasts in order to find suitable surface materials for the transmucosal part of the dental implant. Methods: Twenty specimens were divided into four groups: smooth titanium (Ti-S), smooth zirconia (ZC-S), microgroove titanium (Ti-MG) and microgroove zirconia (ZC-MG) (five specimens in each group). Microgroove modification of titanium and zirconia surfaces was carried out by using fine machining chip system in the last two groups. The width of groove ridge was 60 μm, the width of groove was 60 μm, the depth of groove was 10 μm. The surface morphologies (the groove width and depth) were observed by scanning electron microscope (SEM), the surface roughness, static contact angle and elemental of specimens in each group were detected by SEM, atomic force microscope (AFM), optical contact angle measuring device and energy-dispersion X-ray analysis (EDX). Morphology of human gingival fibroblast (HGF) that arranged along the groove was analyzed using laser scanning confocal microscope by immunofluorescence staining. Differences in cell proliferation were analyzed and compared using cell counting kit. Expression level of intergrin α(5), β(1) and collagen Ⅰ mRNA were compared among different groups by quantitative real-time PCR for 6 h and 3 d. Results: The surface roughness of smooth titanium group and smooth zirconia group was (63.23± 2.55) and (26.78±3.11) nm, respectively. Microgroove zirconia group showed the best hydrophilicity: the static contact angle was 51.2°±2.0°. HGF was arranged along the groove surface, and cell proliferation results showed that proliferation on microgroove zirconia was more significant than that on other groups from 6 h to 7 d (P<0.05). Intergrin α(5) mRNA has the highest expression in microgroove zirconia (P<0.05) in the early adhesion (6 h), and there was no significant difference in the surface expression of intergrin β(1) and collagen Ⅰ mRNA in the early adhesion (6 h) of each group. However, in the late adhesion (3 d), intergrin α(5), β(1) and collagenⅠ mRNA expression in microgroove surface groups were higher than those of the smooth groups (P<0.05). Conclusions: Microgroove zirconia surface has small roughness and good hydrophilicity, which can guide HGF to line up in the groove, and this is beneficial to the HGF proliferation and the expression of structural proteins and functional proteins.