Evaluation of pulpal blood flow during orthodontic space closure: Prospective clinical trial

Introduction: Orthodontic tooth movement (OTM) is a biological process that can affect the vascularization of the dental pulp. The forces exerted on the teeth may increase periapical pressure that could compress the arterioles, which in turn affects pulpal blood flow (PBF). The study aimed to investigate how OTM affects PBF during orthodontic space closure. Methods: A total of 22 adolescent participants who required orthodontic space closure in mandibular posterior sectors were enrolled in a prospective clinical study. The same sliding mechanics, wires, and active elements were used. Patients were observed before OTM, after leveling before space closure, and at the 4th, 7th, 21st, and 28th during active space closure. PBF was measured with laser Doppler (LD) flowmetry. Dental models were obtained with an intraoral scanner. Results: The LD flow values decreased significantly during the observation period (2-way repeated measures analysis of variance, P <0.001). There was a significant difference in LD flow between tooth categories (2-way repeated measures analysis of variance, P <0.001). During space closure, the most pronounced LD flow reduction was observed in singlerooted teeth closest to the residual space. A higher speed of OTM was associated with a greater decrease in LD flow on day 4 of OTM (Pearson correlation, P 5 0.0299). Conclusions: Orthodontic space closure reduced PBF; it was lowest in the early stages of space closure and showed a tendency to increase during the first month. Anterior teeth closer to the interdental space that experiences more OTM and teeth that move faster during initial OTM had a higher risk of reduced blood flow. (Am J Orthod Dentofacial Orthop 2024;166:549-60)