Affiliation:
1. Department of Orthodontics, Faculty of Dentistry University of Oslo Oslo Norway
2. Department of Orthodontics and Dentofacial Orthopedics, School of Dental Medicine University of Bern Bern Switzerland
3. Institute of Dentistry Queen Mary University of London London UK
Abstract
AbstractObjectivesEvaluate long‐term spontaneous occlusal changes following L7 extraction in adolescent patients.Materials and MethodsStudy models of 144 participants (63 males, 81 females) retrospectively assessed prior to L7 extraction (9–16 years old; T1) and following L8 eruption (14–25 years old; T2). All received upper fixed appliances. A sub‐group (n = 86) received no lower fixed appliances and acted as controls. Occlusal changes were compared between treatment (lower fixed appliance) and control (no lower fixed appliance) groups using PAR index. At T2, L8 occlusal outcome was assessed using ABO grading system.ResultsMean follow‐up period 6 (SD 2) years. At T1, lower scores observed in control group for Lower Anterior (P < .001), Midline (P = .033) and Lateral Segments (P = .040) components. At T2, lower scores continued being observed in control group for Midline (P < .001) and Lateral segment (P = .019) components. Higher decrease in Lower Anterior PAR scores observed in treatment group (<.001) with comparable scores between groups at T2 (P = .057). Similar PAR score changes between groups for Lateral Segments, Overjet and Overbite components. At T2, no significant difference observed in Total PAR score reduction between control (83%) and treatment (82%) groups. Good‐to‐acceptable occlusal outcome of the L8 observed in 81.55% of cases at T2 with no difference between groups.ConclusionIn growing patients with mild mandibular crowding, extraction of L7 followed by upper fixed appliance therapy, leads to favourable occlusal changes over a 6‐year follow‐up period, with or without lower fixed appliance therapy, being an alternative extraction protocol where lower fixed appliance therapy is not recommended.