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 α₅, β₁ 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 α₅ 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 β₁ and collagen Ⅰ mRNA in the early adhesion (6 h) of each group. However, in the late adhesion (3 d), intergrin α₅, β₁ 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.

OBJECTIVES: This study aimed to investigate the effect of new biomimetic micro/nano surfaces on the osteoclastic differentiation of RAW264.7 macrophages by simulating natural osteons for the design of concentric circular structures and modifying graphene oxide (GO). METHODS: The groups were divided into smooth titanium surface group (SS), concentric microgrooved titanium surface group (CMS), and microgroove modified with GO group (GO-CMS). The physicochemical properties of the material surfaces were studied using scanning electron microscopy (SEM), contact-angle measurement, atomic force microscopy, X-ray photoelectron spectroscopy analysis, and Raman spectroscopy. The effect of the modified material surface on the cell biological behavior of RAW264.7 was investigated by cell-activity assay, SEM, and laser confocal microscopy. The effect on the osteoclastic differentiation of macrophages was investiga-ted by tartrate-resistant acid phosphatase (TRAP) immunofluorescence staining and quantitative real-time polymerase chain reaction (qRT-PCR) experiments. RESULTS: Macrophages were arranged in concentric circles along the microgrooves, and after modification with GO, the oxygen-containing groups on the surface of the material increased and hydrophilicity increased. Osteoclasts in the GO-CMS group were small in size and number and had the lowest TRAP expression. Although it promoted the proliferation of macrophages in the GO-CMS group, the expression of osteoclastic differentiation-related genes was lower than that in the SS group, and the difference was statistically significant (P<0.05). CONCLUSIONS Concentric circular microgrooves restricted the fusion of osteoclasts and the formation of sealing zones. Osteomimetic concentric microgrooves modified with GO inhibited the osteoclastic differentiation of RAW 264.7 macrophages.
Graphite/pharmacology* ; Titanium/pharmacology* ; Haversian System ; Macrophages ; Cell Differentiation ; Oxides/pharmacology* ; Surface Properties