The purpose of this study was to explore the clinical relevance of the effects of machined/turned, TiO2-blasted and sandblasted/acid-etched titanium oral implant surfaces on nerve conduction. Isolated rat sciatic nerves were placed between two suction electrodes in a pyrex bath containing a tyrode solution. Evoked compound action potentials (cAps) of the nerves were recorded before and after contact with the implants. The mandibular incisors of randomly selected animals were extracted and changes in cAP amplitudes were used as controls. The differences in final cAP values of Astra Tech(R) implants and rat natural teeth were insignificant (P < 0.05), whereas the differences between other groups were significant (P < 0.05). Machined/turned-surface implants did not cause any change in cAPs. A slight decrease in cAPs was observed for TiO2-blasted and sandblasted/acid-etched implants, and the natural teeth. The reductions of cAPs in latter groups were not 50% after an application time of 300 min. The cAP changes of nerves contacting TiO2-blasted and sandblasted/acid-etched oral implants fall within physiologic limits in vitro. Machined/turned, TiO2-blasted, and sandblasted/acidetched titanium implant surfaces do not lead to irreversible neurotoxic effects. (C) 2003 Wiley Periodicals, Inc.