ABSTRACT
BACKGROUND: Surface roughness of implants can directly influence cellular proliferation, differentiation, and gene expression. OBJECTIVE: To observe the early attachment of periodontal ligament cells (PDLCs) to pure titanium with different surface roughness levels, and to study the effect of surface performance on cell differentiation. DESIGN, TIME AND SETTING: Randomized controlled observation/multi-sample comparison study, which was performed at Center of Science and Technology, Gannan Medical College between January 2005 and July 2006. MATERIALS: Pure titanium stick was cut into pieces, of 10 mm diameter and 2 mm thickness, using cutting-off machine, and there were 24 sections in total. Then, the titanium sections were randomly divided into four groups: simple mechanical processing, nitric acid processing, sand blasting processing, and combination group, with 6 sections per group. METHODS: TR240 portable-type surface roughness meter was used in this study. In the simple mechanical processing group, sections were scoured by sand paper alone; in the nitric acid processing group, sections were etched with 65% HNO3 for 1 hour at 100 ℃ after scoured by sand paper; in the sand blasting processing group, sections were sandblasted by 100 μ m AI203 after scoured by sand paper; in the combination group, sections were etched with 65% HNO3 for I hour at 100～C after scoured by sand paper and sandblasted by 100 μ m Al2O3. MAIN OUTCOME MEASURES: Samples were maintained in DMEM for 30 minutes, and the third-passage cells were inoculated. Then, titanium sections were taken out at different time points of 30, 60, 120, 240 minutes, 1, 3, and 7 days. Surface roughness and early attachment of PDLCs were detected under fluorescent microscope. RESULTS: O Quantitative analysis: Surface roughness was (599.5±8.3) nm in the simple mechanical processing group, (406.5 +4.6) nm in the nitric acid processing group, (358.8±11.8) nm in the sand blasting processing group, and (8.7±2.0) nm in the combination group. On the other hand, surface roughness in the simple mechanical processing group was significantly higher Fluorescence observation exhibited that number of PDLCs attaching to pure titanium surface was increased, and the proliferation was greater with the time passing by. in addition, surface roughness of pure titanium was positively associated with number of PDLCs. CONCLUSION: The lighter the surface roughness is, the more the early attachment of PDLCs is, benefiting for cell adhesion and proliferation.