Stability of anterior open bite in permanent dentition treated using extraction or non-extraction methods: A systematic review and meta-analysis of each method

Purpose: To evaluate the literature on the stability of open bite treatment using extraction or non-extraction methods. Methods: Medline, Scopus, and Cochrane library were electronically searched until December 2017. Studies were considered for evaluation if they reported overbite measurements pretreatment, post-treatment, and at least 1-year post-retention for non-surgical orthodontic patients with permanent dentition, treated by extraction or non-extraction methods The risk of bias of the selected articles was assessed. Results: The search retrieved 985 articles, only 6 articles were included after applying the selection criteria. Two articles were case-control studies, and the other four were case series studies. The mean stability rates were 93.53% and 73.68% in extraction and non-extraction cases, respectively. Because each included study presented data of either the extraction or non-extraction method, it was not possible to perform a meta-analysis by pooling the results of the studies to compare the two methods. However, meta-analysis was conducted to compare the overbite between post-treatment and post-retention within each method. The results showed no significant change in extraction cases (mean difference (MD) 0.49, 95% CI -0.18-1.16; P=0.15), but showed a significant change in non-extraction cases (MD 1.12, 95% CI 0.77-1.46; P < 0.00001). Conclusions: Our findings indicated no significant relapse in extraction cases, but a significant relapse in non-extraction cases. However, due to no direct comparison, the optimum treatment method for open bite patients with permanent dentition remains questionable. Further studies with a high level of evidence that compare both treatment methods are needed to draw a definitive conclusion. (C) 2018 Elsevier Ltd and The Japanese Orthodontic Society. All rights reserved.