Effects of Induced Malocclusion on Vertebral Alignment in Rats: A Controlled Study by CBCTs

SIMPLE SUMMARY: Nowadays, there is insufficient available evidence to validate a correlation between dental occlusion disorders and spinal curvature, and therefore, more studies are necessary to clarify how and to what extent the modifications of the occlusion might affect vertebral spine biomechanics. The following paper is a controlled study on rats that aims to induce a malocclusion in rats’ mouths by a bite-raising on the upper molars and then to check the alteration of vertebral alignment over time by a CBCT analysis. Alteration of vertebral alignment in rats with induced malocclusion could support the hypothesis of a correlation between occlusal contact and body posture and open the way for further studies on mandibular repositioning and posture control in humans. ABSTRACT: This study aimed to evaluate with CBCTs the alteration of vertebral alignment over time of induced malocclusion in rats. Crown pads increasing the vertical dimension of 0.5 mm were applied on the upper molars at one randomly selected side of the maxilla in rats (premature contact side) while the opposite side was left untreated (control side). Four groups were organized, ten animals each. In groups A, B, and C, the crowns were applied at time 0 (t-0). In group A, the crowns were removed after 2 weeks (t-2w) and euthanized after two more weeks, while in groups B and C, the animals were euthanized after 2 and 4 weeks (t-4w), respectively. No premature contacts were applied in group D. CBCTs were taken at t-0 in all animals before applying the crowns, at t-2w in group A before removing the crowns, and in all groups before the euthanasia. The changes in the iliac crest angle (ICA) that formed between the superior external margin of the iliac crest and the vertebral spine were evaluated. In groups A and B, after 2 weeks, the changes in ICA were statistically significant at p = 0.028 and p = 0.042, respectively. In group C, and in the control group D, the changes of ICA were not statistically significant (p = 0.058 and p = 0.414, respectively). In conclusion, the incease in monolateral occlusion in the molar region yielded a rotation of the lumbo-sacral segment towards the same side of the occlusal bite-raising.