The aim of this study was to investigate the effects of hydroxyapatite-coated and commercially pure titanium oral implants on nerve conduction. Isolated rat sciatic nerves were placed between two suction electrodes in a bath containing a tyrode solution. The implants were brought into intimate contact with the nerves and evoked compound action potentials (cAPs) were recorded before and after contact with the implants. The commercially pure titanium implants did not cause any change in cAPs. A gradual reduction in cAPs was observed for hydroxyapatite-coated implants. However, this reduction was < 50% after an application time of 120 min. Recovery of the cAPs in this group was recorded after approximately 60 min. We conclude that, although intimate contact with hydroxyapatite-coated implants leads to a reduction in cAPs in nerves in vitro, neither this surface nor a commercially pure titanium surface leads to irreversible neurotoxic effects.

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The purpose of this study was to explore the clinical relevance of the effects of machined/turned, TiO(2)-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 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 TiO(2)-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 TiO(2)-blasted and sandblasted/acid-etched oral implants fall within physiologic limits in vitro. Machined/turned, TiO(2)-blasted, and sandblasted/acid-etched titanium implant surfaces do not lead to irreversible neurotoxic effects.

Controlled release of tramadol from PHB microspheres is possible, and pain relief during epidural analgesia is prolonged by this drug formulation compared with free tramadol.