Effectiveness and side effects of orthodontic traction of impacted maxillary incisors in a labially inverted position: A systematic review

Introduction: Treatment of impacted upper incisors in a labially inverted position is challenging for orthodontists, and its prognosis has not been established in the literature. Thus, this systematic review aimed to determine the effectiveness and side effects of orthodontic traction of impacted maxillary incisors in a labially inverted position. Methods: A comprehensive search was conducted in multiple databases, including MEDLINE (via PubMed), Scopus, Embase, Science Direct, and LILACS, up to June 30, 2024. Initially, 1640 articles were identified, and after applying specific selection criteria, 11 articles were selected for full-text evaluation. Following the review, only six studies were deemed relevant, comprising one before-and-after study, two longitudinal retrospective studies, and three cross-sectional studies. Newcastle-Ottawa and Risk of Bias (ROB-2) tools were used to assess the risk of bias in the selected studies. Results: The average duration of traction for maxillary labially inverted impacted central incisors ranged from 8.60 ± 1.26 months to 18 ± 6.0 months, with all cases being successfully treated. Following traction, the clinical crown height of the incisors was significantly higher compared to the control group (P < 0.01). Similarly, the root length of the impacted incisors after traction was shorter in the impaction group (approximately 2 mm) compared to the control group. Likewise, the thickness of the alveolar bone varied among different studies. Some authors noted that the treatment group had a smaller thickness (about 0.5 mm) compared to the control group (P < 0.05), while other authors found similar thickness after treatment. Conclusions: Although there are few reported studies with a low risk of bias, it is clear that it is possible to successfully treat labially inverted impacted maxillary central incisors with apparently few side effects. Following traction, the clinical crown height of these incisors increased, while the root length was shorter than their normally erupted contralateral teeth.