The Impact of Ovariectomy and Dental Trauma on Dental Pulp, on Tooth Movement and Internal Root Resorption: Findings from a Rat Model

Background/Aim: A patient's hormonal status significantly impacts the orthodontist's conduct, because it can directly influence the success of the treatment. Estrogen reduction is associated with a decrease in alveolar bone mineral density, increased tooth movement, root resorption and changes detinopulpar complex. This study aimed to evaluate the effects of ovariectomy associated with dentoalveolar trauma during induced tooth movementand its influence on the histological structure of the pulp dentin complex in rats.

Study Design: Experimental research.

Methodology: Forty-eight Wistar rats were separated into eight experimental groups (n=6/group): Control group (CLT); animals submitted to dentoalveolar trauma (DT); animals submitted to ovariectomy (OVX); animals submitted to dentoalveolar trauma and ovariectomy (DT + OVX); animals submitted to induced tooth movement (ITM); animals submitted to induced tooth movement and trauma (ITM + DT); animals submitted to tooth movement and ovariectomy (ITM + OVX) and animals submitted to tooth movement, trauma and ovariectomy (ITM+DT+OVX). At the end of the experimental period, animals were euthanized, and the maxillae were removed, fixed in 10% formaldehyde, decalcified, embedded in paraplast, sectioned to 5µm and stained with hematoxylin and eosin. The first upper right molars were examined to diagnose pulpal changes. The data were compared by analysis of variance (One-Way ANOVA) followed by Tukey’s post-hoc test.

Results: The tooth movement rate was significantly higher in animals in the ITM+DT+OVX group when compared to the other groups (p<0.05). The cellularity pattern of the pulp tissue did not change in any of the experimental groups. In the analysis of dystrophic changes, only the ITM + OVX and ITM+DT+OVX groups presented hyalinization areas. Regarding hemodynamic changes, vascular congestion and thrombosis were similar in all groups. The only alteration in dentin observed was the internal root resorption, in the animals of the DT+OVX, ITM, ITM+OVX and ITM+DT+OVX groups. The ITM group presented larger resorption areas than the ITM+DT and ITM+DT+OVX groups and the ITM+OVX group presented the largest amounts of root resorption areas when compared with all experimental groups.

Conclusion: Induced tooth movement associated with ovariectomy, and experimental extrusive luxation increased in the rate of tooth movement, pulp hyalinization and larger areas of internal root resorption. These findings are important for guiding personalized orthodontic for women experiencing hormonal imbalances and dental trauma.