Neurogenic inflammation in periimplant and periodontal disease: A case-control split-mouth study

Although the regulatory effects of substance-P (SP), neurokinin-A (NKA), calcitonin gene-linked peptide (CGRP) and neuropeptide-Y (NPY) on periodontal inflammatory responses have been described, the effects of these neuropeptides on healthy and diseased periimplant tissues are not clearly defined.

Thirty-nine implants loaded at least for 12 months with their symmetrically matching teeth were evaluated and compared by a split-mouth study design. Six study groups were created in this regard as follows: group 1 (healthy periodontal tissues), group 2 (healthy periimplant tissues), group 3 (gingivitis), group 4 (periimplant mucositis), group 5 (periodontitis) and group 6 (periimplantitis). Clinical examinations included Silness-Löe plaque index, Löe-Silness gingival index, bleeding on probing, probing pocket depth and clinical attachment level measurements. Gingival crevicular fluid and periimplant sulcular fluid samples were collected, and the concentrations of neuropeptides were determined by enzyme-linked immunosorbent assay. Their levels and correlations were investigated together with the clinical parameters.

Neuropeptide levels were different in the teeth and implant groups according to the periodontal status (p < 0.001). SP and NKA levels were increased, whereas CGRP and NPY levels were decreased in the diseased states. There were no differences between the neuropeptide levels of matching teeth and implants (groups 1-2, groups 3-4 and groups 5-6; p > 0.05).

Our study demonstrated the presence of local neuropeptides in healthy and diseased periimplant tissues. The neurogenic inflammatory responses were also found to be similar in both periimplant and periodontal tissues.