A Novel Method to Evaluate the Neurocompatibility of Dental Implants

Purpose: To evaluate the neurocompatibility of different types of dental implant surface treatments using the P19 neural cell line. Materials and Methods: P19 cells were plated and supplemented with retinoic acid to grow as aggregates for 4 days. Twenty dental implants were selected from four different implant systems with five different surface treatments. The implants were divided into four groups (n = 5), placed inside medical rings, and fixed by injection of warm gutta-percha using a thermoplastic injection technique. Implant molds were placed inside graded culture dishes, and culture medium containing P19 neural cells were plated on the dishes for 4 days. After 24 hours, the surfaces of the implant molds were covered with self-curing resin to make a replica of each mold surface. Replicas were assessed under a scanning electron microscope, and the number of cells and the total cells covering the areas were evaluated. Data were analyzed by a post hoc Tukey test. Results: There were significant differences in P19 cell counts between all modified and electropolished surfaces. The highest P19 cell counts were shown on OsseoSpeed and Laser-Lok surfaces. The lowest counts were shown on the Nanotite surface at the collar. OsseoSpeed and Laser-Lok surfaces showed higher counts at the collar than on the body; the opposite was seen for SLActive and Nanotite surfaces. Cell-covered areas on Laser-Lok surfaces showed significantly higher values than the resorbable blasted media (RBM)-treated surfaces, while it was not significantly different from the OsseoSpeed surface of collar regions. SLActive collar regions showed larger cell-covered areas than the SLActive body surfaces, but this was not significant. Conclusion: All test surface treatments in this study showed better neurocompatibility than control group surfaces. The Laser-Lok, RBM, and OsseoSpeed surfaces were superior to the Nanotite and SLActive surfaces in terms of neurocompatibility. Keywords: dental implants, neurocompatibility, P19 cell line, titanium