Animal study of sensory function of nerve fibers surrounding dental implant

PURPOSE: To investigate the distribution of sensory nerve fibers in the tissue of peri-implant bone and to study the reconstruction procedure of somatosensory evoked potentials of unloaded dental implant.METHODS: The bilateral 2nd,3rd and 4th mandibular premolars and the 1st molars were extracted from 3 beagle dogs.Three months later,4 screw-type implants were inserted.Then 1,6 and 12 weeks later,the sensory nerve action potential(SNAP) tests were performed.The stimulating electrode was connected to the implant,and the recording electrodes were fixed on the inferior alveolar nerve stem to record the amplitude of SNAP.Then the dogs were sacrificed,and the specimens were prepared for immunohistochemical examination.The SNAP results were statistically analyzed using SPSS17.0 software package.RESULTS: SNAP of the inferior alveolar nerve stem could be recorded following stimulations to each implant.The difference in SNAP amplitudes between the 1-week group and the other two groups was significant(P0.05).But there was no significant difference between the 6-week and 12-week group.Some NFP-positive nerve fibers were found in the tissues of peri-implant bone.These fibers localized in both the bone marrow space and in the peri-implant fibrous tissues.CONCLUSIONS: Neuroreceptors do exist in the tissue of peri-implant bone,but much less than the periodontal ligament.These neuroreceptors could receive electrical stimulus then evoke SNAP of the inferior alveolar nerve stem.In unloaded condition,the reconstruction of never endings in the peri-implant bone tissue is apparently time-dependent.