Effects of ultraviolet treatment and alendronate immersion on osteoblast-like cells and human gingival fibroblasts cultured on titanium surfaces

Abstract

In this study, we evaluated the effects of ultraviolet (UV) treatment and alendronate (ALN) immersion on the proliferation and differentiation of MG-63 osteoblast-like cells and human gingival fibroblasts (HGFs) cultured on titanium surfaces. MG-63 cells were used for sandblasted, large grit, and acid-etched (SLA) titanium surfaces, and HGFs were used for machined (MA) titanium surfaces. SLA and MA specimens were subdivided into four groups (n = 12) according to the combination of surface treatments (UV treatment and/or ALN immersion) applied. After culturing MG-63 cells and HGFs on titanium discs, cellular morphology, proliferation, and differentiation were evaluated. The results revealed that UV treatment of titanium surfaces did not alter the proliferation of MG-63 cells; however, HGF differentiation and adhesion were increased in response to UV treatment. In contrast, ALN immersion of titanium discs reduced MG-63 cell proliferation and changed HGFs into a more atrophic form. Simultaneous application of UV treatment and ALN immersion induced greater differentiation of MG-63 cells. Within the limitations of this cellular level study, simultaneous application of UV treatment and ALN immersion of titanium surfaces was shown to improve the osseointegration of titanium implants; in addition, UV treatment may be used to enhance mucosal sealing of titanium abutments.

Figure 1

Representative SEM images of MG-63 cells cultured on titanium surfaces in the S, SUV, SAN, and SUVAN groups. (a) SEM images at 500x magnification, (b) SEM images at 2000x magnification.

Figure 2

Representative SEM images of HGFs cultured on titanium surfaces in the M, MUV, MAN, and MUVAN groups. (a) SEM images at 500x magnification, (b) SEM images at 2000x magnification.

Figure 3

Effects of UV treatment and ALN immersion on cellular proliferation, as determined using WST-8 assays. Cellular proliferation was expressed as optical density (OD). (a) OD of MG-63 cells in the S, SUV, SAN, and SUVAN groups; (b) OD of HGFs in the M, MUV, MAN, and MUVAN groups. Data are expressed as means ± S.E.M. (n = 6). *P < 0.05, **P < 0.01, ***P < 0.001 for comparisons among groups. The asterisks indicate statistically significant differences between the groups.

Figure 4

Effects of UV treatment and ALN immersion on ALP activity in MG-63 cells, as assessed by spectrophotometry after 3 days of culture, in the S, SUV, SAN, and SUVAN groups. Data are expressed as means ± S.E.M. (n = 5). *P < 0.05 for comparisons among the groups. The asterisks indicate statistically significant differences between the groups.

Figure 5

Effects of UV treatment and ALN immersion on cellular differentiation in HGFs in the M, MUV, MAN, and MUVAN groups. RT-PCR data indicate the relative mRNA expression of (a) integrin-β1, (b) type I collagen, (c) type III collagen, (d) fibronectin, and (e) laminin5 after 24 h of culture. Data are expressed as means ± S.E.M. (n = 5). *P < 0.05 for comparisons among the groups. The asterisks indicate statistically significant differences between the groups.