Methods: A cross-sectional prospective study was undertaken on 34 subjects to compare clinical measures of neural sensitivity of the maxillary branch of the human trigeminal nerve before, during, and up to 6-months following orthodontic tooth movement using quantitative sensory testing. The upper left central incisor was subject to pressure and electrical testing. Repeatability studies were undertaken for each of the modalities tested. Pressure detection thresholds were found to be the most reproducible, demonstrating insignificant (p=0.683) systematic bias, and small random error (-0.65/+0.55 mg).
Results: Overall, there was a trend for a marked decrease in pressure and electrical thresholds 24 hours after archwire placement with a return towards pre-treatment thresholds 4-6 months after active therapy had ceased. However, due to large inter-individual variability in responses and low sample numbers, statistical analysis failed to reveal any significant changes in sensory thresholds as a result of orthodontic treatment (p>0.05, ANOVA). No differences in sensory thresholds were found according to age or gender.
Conclusion: Findings from this preliminary study seem to show that orthodontic tooth movement in human subjects does not cause any significant short or long-term changes in the sensory thresholds of associated supporting dento-alveolar tissues. Nonetheless, the orthodontic patient does provide a unique model in which to study inflammation-induced peripheral and central sensory changes and further research is indicated in this interesting field of clinical neuroscience.