Effect of Orthodontic Tooth Movement on Pulp Vitality in Previously Traumatized Teeth: A Prospective Cohort Study

Introduction: Dental trauma commonly affects the anterior teeth of young individuals, often leading to pulpal compromise through neurovascular damage. Orthodontic tooth movement (OTM) may further stress these teeth, thereby increasing the risk of loss of vitality. This prospective cohort study aimed to assess the impact of OTM on pulp vitality in previously traumatized permanent anterior teeth compared to non-traumatized contralateral controls. Materials and methods: Sixty patients (mean age: 16.5 ± 3.2 years) participated, each providing one traumatized anterior tooth (traumatized group) and one non-traumatized contralateral tooth (control group) treated with fixed orthodontics. The trauma types included enamel-dentin fractures, subluxation, and enamel-dentin-pulp fractures, with a mean time since injury of 3.8 ± 2.1 years. Pulp vitality was evaluated using cold and electric pulp testing at baseline and at 3, 6, and 12 months after OTM initiation. Data were analyzed using McNemar’s test, Kaplan-Meier survival analysis with log-rank test, and relative risk estimation (p < 0.05). Results: Baseline vitality was positive in 58 (96.7%) traumatized teeth and 60 (100%) control teeth (p = 0.154). Vitality in the traumatized group declined to 54 (90.0%) at three months (p = 0.047), 50 (83.3%) at six months (p = 0.015), and 48 (80.0%) at 12 months (p = 0.013), while the controls showed minimal changes. Kaplan-Meier survival analysis revealed a mean vitality survival of 10.8 months in traumatized teeth versus 11.8 months in controls (log-rank p = 0.016). Pulp necrosis occurred in eight (13.3%) traumatized teeth versus one (1.7%) control tooth (p = 0.035). Calcific metamorphosis was observed in four (6.7%) and in none of the controls (p = 0.126). The external root resorption rates were similar. Conclusion: OTM significantly increased the risk of pulp vitality loss and pulpal complications in previously traumatized teeth. These findings highlight the need for cautious interdisciplinary management, including the use of light orthodontic forces (≤25-50 g), avoidance of heavy intrusive movements, regular pulp sensibility monitoring at baseline and at three-month intervals, and thorough patient counseling regarding the risk of pulp necrosis and possible endodontic intervention. Multicenter studies using objective pulpal blood flow assessment methods are recommended to strengthen evidence-based protocols.