Osteogenic capacity of PLGA embedding simvastatin for biofunctionalization of titanium abutments

Background

Even though the high success rate of oral rehabilitations using dental implants, the periimplant bone loss can still be observed. Biomaterials have been studied with incorporation of drugs that can be released locally and help the process of biological reestablishment and periimplant tissue maintenance. To obtain a greater marginal stability, a titanium surface coating was proposed as a biofunctionalized prosthetic abutment.

Aim/Hypothesis

This study evaluates the capacity of 0.6% simvastatin (SIM), incorporated into polylactic co-glycolic acid (PLGA) on titanium (Ti) surface, to promote osteogenic differentiation of stem cells of human exfoliated deciduous teeth (SHEDs).

Materials and Methods

Ti disks (grade IV + 8x3 mm) were distributed in- G1) Ti+PLGA+ and G2) Ti+PLGA+SIM0.6%. G1 and G2 samples received treatment by immersion in PLGA or PLGA+SIM0.6% solution, respectively, dried by solvent evaporation technique and then sterilized by ethylene oxide. After samples preparation, SHEDs were seeded on disks surface in culture plates with non-osteogenic medium. In addition to experimental groups, three cell control groups were tested- G3) SHEDs in non-osteogenic medium+ G4) SHEDs in osteogenic medium+ and G5) osteoblasts MC3T3-E1 in osteogenic medium. The osteogenic differentiation capacity was analyzed by the quantification of the alkaline phosphatase (ALP) activity (3,7, and 10 days), and the bone proteins expression (14 and 21 days)- osteocalcin (OCN) and osteonectin (ONT). The tests were performed in triplicate comparing G1, G2, and the cells control groups. Results were statistically analyzed by one-way analysis of variance (one-way ANOVA) followed by Tukey's test (P < 0.05).

Results

ALP activity in G1, G2, and G3 were higher than G5 and G6 at all experimental times (P < 0.0001). At days 3 and 7, G1 and G2 were similar to G3. At day 10, G3 showed higher ALP activity than G1 (P = 0.0085) and G2 (P < 0.05). OCN expression was higher in G1 and G2 than the control groups at both experimental times (P < 0.0001). At day 14, G2 presented the highest amount of OCN (P = 0.0049) and the control groups showed similar results. G1 and G2 had higher values of ONT than the control groups at both experimental times (P < 0.0001). At day 14, G2 showed the highest amount of ONT (P < 0.0004). At day 21, between the control groups, G3 had the highest values (P < 0.0001) of ONT.

Conclusion and Clinical Implications

In general, the biofunctionalized Ti surface with PLGA or PLGA+SIM0.6% presented higher influence on SHEDs osteogenic differentiation than control groups. However, higher bone proteins expression was observed in SIM presence, showing the drug induce SHEDs osteogenic differentiation.