Ultraviolet light-treated zirconia with different roughness affects function of human gingival fibroblasts in vitro: the potential surface modification developed from implant to abutment.
OBJECTIVE
To evaluate whether ultraviolet (UV) light irradiation of smooth and rough zirconia disks enhances its biocompatibility with human gingival fibroblasts (HGFs).


METHODS
Zirconia disks were divided into four groups: smooth control (S-C), smooth with UV light treatment (S-UV), rough control (R-C), and rough with UV light treatment (R-UV). The surface morphology and wettability were analyzed, and X-ray photoelectron spectroscopy was carried out. The cultured HGFs' adhesive density, morphology, proliferation, and collagen synthesis were measured on different time points from 3 h to 7 days.


RESULTS
After 24-h UV light treatment, contact angles decreased from 51.98° (S-C) and 63.87° (R-C) to 33.76° (S-UV) and 36.15° (R-UV). X-ray photoelectron spectroscopy analysis showed that surface C/O ratio reduced from 1.86 and 2.39 to 1.33 and 1.19. After UV light treatment, cells initial spreading areas and perimeters were doubled on S-UV disks and nearly tripled on R-UV disks. Three hours cell adhesion was enhanced on S-UV disks, and 24-h cell density was increased on R-UV. Cell proliferation of 48 or 72 h was all significantly changed on UV-treated disks. Cells on R-UV also released highest level of Col-1 after 3 and 7 days, whereas those on S-UV produced less levels compared with control.


CONCLUSIONS
Our study demonstrated for the first time that UV light treatment on rough (Ra = 0.19 ± 0.03 μm) zirconia had a positive effect on behavior of HGFs, including 24-h cell adhesion, proliferation, and collagen release. The effect varied with surface roughness and time point. Surface morphology and hydrophilicity, as two interacted factors, both are governed on HGFs behavior.
Department of Prosthodontics, Peking University School of Stomatology, Haidian District, Beijing, 100081, People's Republic of China.
Yang
Y
Yang
Jianfeng
J
Zhou
Xiaoqiang
X
Liu
Miao
M
Zheng
Jianjun
J
Yang
Jianguo
J
Tan
D002478:Cells, Cultured; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism*; D005881:Gingiva / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D008422:Materials Testing; D019736:Prostheses and Implants; D013499:Surface Properties; D013997:Time Factors; D014466:Ultraviolet Rays; D015040:Zirconium / Q000737:chemistry*
D015040:Zirconium; C028541:zirconium oxide
UV light bioactivation; fibroblasts; implant interface; surface roughness; zirconia