Expression of Substance P, Calcitonin Gene-Related Peptide and Vascular Endothelial Growth Factor in human dental pulp under different clinical stimuli

Background To quantify the expression of SP, CGRP, and VEGF in human dental pulps as a response to occlusal trauma, moderate orthodontic forces, and occlusal trauma plus moderate orthodontic forces simultaneously.Methods Forty human dental pulp samples were collected from healthy premolars indicated for extraction for orthodontic reasons in 20 patients. Patients were divided into four groups with 10 samples each (5 lower and 5 upper premolars from each patient): Healthy pulp control group, occlusal trauma group, moderate orthodontic forces group; and occlusal trauma plus moderate orthodontic forces group. Stimuli were applied for 24 h before tooth extraction in all experimental groups. All samples were processed, and SP, CGRP, and VEGF were measured by radioimmunoassay. The ANOVA test was performed to establish significant differences between groups and Tukey’s HSD post hoc comparisons were also performed.Results The highest increase in SP, CGRP, and VEGF expressions was found in the occlusal trauma plus orthodontic forces group, followed by the moderate orthodontic forces, the occlusal trauma and the control groups, with statistically significant differences between all groups (ANOVA p<0.001). All pairwise post-hoc comparisons were also significant (Tukey HSD p<0.001).Conclusion SP, CGRP, and VEGF expressions significantly increase in human dental pulps when stimulated by occlusal trauma combined with moderate orthodontic forces, as compared with these two stimuli applied independently. Name of the registry: Importance of Neurogenic Inflammation in the Angiogenic Response of the Dental Pulp as a Defensive ResponseTrial registration number: NCT03804034Date of registration: 01/15/2019 Retrospectively registeredURL of trial registry record: https://clinicaltrials.gov/ct2/show/NCT03804034?term=NCT03804034&draw=2&rank=1