Role of Titanium Surface Properties on Primary Gingival Cell Behavior

Objectives: Soft tissue responses to titanium are not well understood. This exploratory study aims to understand the role of titanium surface properties on gingival fibroblast and epithelial cell behavior under culture conditions mimicking healthy tissue and periodontal disease.
Methods: Titanium discs (Ti-6Al-4V) were modified to create three distinct surface roughness (Ra): 1) polished (Ra=0.06 ± 0.02 µm), 2) machined (Ra=0.51 ± 0.02 µm) and 3) Sand-blasted-acid-etched (SLA) (Ra=1.66 ± 0.01 µm). Primary human gingival fibroblasts (HGFp) and epithelial cells (HGEPp) were cultured in MEM (with FBS, PSF, L-glutamine) and in CnT Prime Epithelial Cell Culture Medium, respectively. HGFps and HGEPps were inoculated onto each disc (50,000 cells/cm²). At days 1, 4, and 7 an MTT assay was performed on a subset of the discs to evaluate cell viability while remaining discs were immunostained to examine cell adhesion and morphology. In addition, cell behavior was investigated following priming with inflammatory cytokines and exposure to LPS (P.gingivalis). Cells were inoculated onto polished, machined and SLA titanium and glass (control) discs (50,000 cells/cm²). Cells were then primed with 1) 1000 U/ml INF-γ then stimulated with 0.1 µg/ml LPS (INF+LPS), 2) 10 ng/ml TNF-∝ before stimulating with LPS (TNF+LPS), 3) activated with LPS only (LPS), or 4) remained in their standard culture medium. Cell morphology and viability was assessed via immunostaining and an MTT assay, respectively.
Results: Preliminary data reveals improved HGFp adhesion and proliferation on the SLA titanium disks, no significant difference among surfaces for HGEPps. A significant difference (P<0.01) in HGEPp viability between LPS treatment and control groups was observed. INF+LPS and TNF+LPS groups had significant decrease in viability compared to LPS alone (p<0.01).
Conclusions: Based on this pilot study, it appears that rough titanium surfaces promote adhesion and proliferation. INF-γ and TNF-∝ primed HGFp and HGEPp respond differently to P.gingivalis LPS.