Background. The composite attachment loss during orthodontic clear aligner therapy is an adverse event that commonly happens in our daily practice. However, there is a lack of related statistical analysis and studies analyzing the related risk factors. Therefore, the aim of this study is to assess the incidence of attachment loss during orthodontic clear aligner therapy and to identify rick factors that may predict such event. Materials and Methods. The demographics and clinical variables of 94 patients undergoing clear aligner therapy (27 males and 67 females; average age: 27.60 ± 0.86   years ) were recorded. Both patient-related and tooth-related attachment loss was recorded. The chi-squared test and logistic regressive analysis were applied to identify the potential risk factors. SPSS for Mac (version 23.0, IBM, USA) was used for statistical analyses. P < 0.05 was considered statistically significant. Results. Our study suggested that the risk factors for attachment loss include frequent aligner removal (≥ 5 times a day) ( losing   rate = 60.0 % , P = 0.005 ), aligner wear time less than 18 hours a day ( losing   rate = 50.8 % , P = 0.014 ), eating without aligners inserted ( losing   rate = 47.9 % , P = 0.034 ), utilizing aligner tray seaters ( losing   rate = 48.2 % , P = 0.006 ), and unilateral mastication ( losing   rate = 52.1 % , P = 0.002 ). The multivariable logistic regression analysis indicates that aligner wear time less than 18 hours a day ( P = 0.020 , B = 0.925 ), using aligner tray seaters ( P = 0.007 , B = 1.168 ), and unilateral mastication ( P = 0.034 , B = − 0.458 ) were considered independent factors that can predict the composite attachment loss in orthodontic clear aligner therapy. Conclusion. Wearing aligner less than 18 hours a day, using aligner tray seaters, and unilateral mastication may contribute to increased incidence of composite attachment loss during orthodontic clear aligner therapy.

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Objectives. We aimed to summarize the current evidence regarding the impact of extraction vs. nonextraction in orthodontic treatment on patients’ soft-tissue profile with malocclusion. Methods. Between April 30th and November 30th, 2020, we searched PubMed and SCOPUS for published papers from inception to November 2020 using “orthodontic,” “extraction,” “nonextraction,” and “Malocclusion.” Included studies were summarized, and relevant data were extracted and analyzed using Review Manager 5.4. Results. Pooled data from four controlled trials demonstrated a nonsignificant difference between extraction and nonextraction in terms of SNA ( MD = 0.50 , 95% CI: -0.37, 1.38; p = 0.26 ), SNB ( MD = 0.11 , 95% CI: -1.23, 1.44; p = 0.88 ), FMA ( MD = 1.82 , 95% CI: -2.39, 6.02; p = 0.40 ), IMPA ( MD = 0.06 , 95% CI: -8.83, -8.94; p = 0.99 ), overjet ( MD = − 1.47 , 95% CI: -6.21, 3.26; p = 0.54 ), and overbite ( MD = 0.50 , 95% CI: -1.40, 2.40; p = 0.60 ). On the other hand, the extraction method significantly increased the ANB compared with the nonextraction group ( MD = 0.78 , 95% CI: 0.25, 1.31; p = 0.004 ). Conclusion. The current evidence demonstrated that nonextraction protocols for orthodontic treatment are a safe and effective alternative to extraction protocols; individually tailored treatment strategies should be applied. More randomized controlled trials are critically needed to safely make an evidence-based treatment conclusion.

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