S-Space College of Dentistry/School of Dentistry (치과대학/치의학대학원) Dept. of Dentistry (치의학과) Theses (Ph.D. / Sc.D._치의학과)
Osteogenic potential and reaction to human gingival fibroblasts of (Y, Nb)-Zirconia
(Y, Nb)-지르코니아의 골형성능 및 치은세포 반응에 관한 연구
- 치의학대학원 치의학과
- Issue Date
- 서울대학교 대학원
- dental implant; titanium; zirconia; LTD; niobium; osteogenic potential; human gingival fibroblasts(HGFs); mucosal sealing
- 학위논문 (박사)-- 서울대학교 대학원 : 치의학대학원 치의학과 치과보철학 전공, 2016. 2. 한중석.
Osteogenic Potential and Reaction to Human Gingival Fibroblasts of (Y, Nb)-Zirconia
Department of Prosthodontics
The graduate school
Seoul National University
Part I: Comparison of the osteogenic potential of titanium and modified zirconia-based bioceramics
Zirconia is now favored over titanium for use in dental implant materials because of its superior aesthetic qualities. However, zirconia is susceptible to degradation at lower temperatures. In order to address this issue, we developed modified zirconia implants that contain tantalum oxide or niobium oxide. Cells attached as efficiently to the zirconia implants as to titanium-based materials, irrespective of surface roughness. Cell proliferation on the polished surface was higher than that on the rough surfaces, but the converse was true for the osteogenic response. Cells on yttrium oxide (Y2O3)/tantalum oxide (Ta2O5)- and yttriym oxide (Y2O3)/niobium oxide (Nb2O5)-containing tetragonal zirconia polycrystals (TZP) discs ((Y, Ta)-TZP and (Y, Nb)-TZP, respectively) had a similar proliferative potential as those grown on anodized titanium. The osteogenic potential of MC3T3-E1 pre-osteoblast cells on (Y, Ta)-TZP and (Y, Nb)-TZP was similar to that of cells grown on rough-surface titanium. These data demonstrate that improved zirconia implants, which are resistant to temperature-induced degradation, retain the desirable clinical properties of structural stability and support of an osteogenic response.
Keywords: dental implant
Part II: Characterization of human gingival fibroblasts on zirconia surfaces containing niobium oxide
It was indicated that tetragonal zirconia polycrystal (TZP) containing yttria (Y2O3) and niobium oxide (Nb2O5) ((Y, Nb)-TZP) could be an adequate dental material to be used at esthetically important sites. The (Y, Nb)-TZP was also proved to possess its osteogenic potential comparable with those conventional dental implant material, titanium (Ti). The objective of the current study was to characterize cellular response of human gingival fibroblasts (HGFs) to smooth and rough surfaces of the (Y, Nb)-TZP disc, which were obtained by polishing and sandblasting, respectively. Various microscopic, biochemical, and molecular techniques were used to investigate the disc surfaces and cellular responses for the experimental (Y, Nb)-TZP and the comparing Ti groups. Sandblasted rough (Y, Nb)-TZP (Zir-R) discs had the highest surface roughness. HGFs cultured on polished (Y, Nb)-TZP (Zir) showed a rounded cell morphology and light spreading at 6 h after seeding and its proliferation rate significantly increased during seven days of culture compared to other surfaces. The mRNA expressions of type I collagen, integrin α2 and β1 were significantly stimulated for the Zir group at 24 h after seeding. The current findings, combined with the previous results, indicate that (Y, Nb)-TZP provides appropriate surface condition for osseointegration at the fixture level and for peri-implant mucosal sealing at the abutment level producing a suitable candidate for dental implantation with an expected favorable clinical outcome.
Keywords: dental implant
human gingival fibroblasts (HGFs)