The effect of orthodontic separator and short-term fixed orthodontic appliance on inflammatory mediators and somatosensory function.

BACKGROUND: Although inflammation can alter cytokines release and nerve function it is not yet fully established if orthodontic-induced inflammation can cause significant extra-oral trigeminal somatosensory alterations and release of inflammatory chemical mediators.

OBJECTIVE: The primary aim of this study was to investigate the impact of orthodontic separator and short-term fixed orthodontic appliance on the extra-oral trigeminal somatosensory function and concentrations of cytokines in the gingival crevicular fluid (GCF).

METHODS: Twenty-two female patients were evaluated as follow: baseline, 24h-after elastomeric separator (-aES), 24h and 1month after bonding brackets (-aBB) at both arches. The outcome variables were: self-reported pain (Visual Analog Scale), QSTs (current perception threshold-CPT, cold detection threshold-CDT, warm detection threshold-WDT, mechanical detection threshold-MDT, mechanical supra threshold-MST and wind-up ratio-WUR. All QSTs were performed at infra-orbital and mental nerve entry zone at patient's dominant side. In addition, GCF samples in order to assess cytokines profile (IL-1β,IL-8,IL-6 and TNF-α) were collected. ANOVA and Tukey's post hoc analyses were performed (a=5%).

RESULTS: Patients reported higher pain intensity 24h-aBB compared to baseline and 24h-aES (p<0.050). Patients were less sensitive to pin prick pain (MST) at 24h-aBB and 1month-aBB compared to baseline (p<0.006). Significant increases in IL-6 levels were observed 24h-aBB (p<0.001). Multiple comparison analysis showed significant increase in IL-1β levels (p<0.001) and TNF-α (p<0.001) 1month-aBB compared to baseline.

CONCLUSION: Elastomeric separators only induced mild pain and were not able to significantly increase pro-inflammatory cytokines level in the GCF. In addition, orthodontic fixed appliance may induce only minor somatosensory changes at extra-oral trigeminal locations. This article is protected by copyright. All rights reserved.