Evaluating the Lower Anterior Facial Height in Patients Treated with Extraction Versus Non-extraction Fixed Mechanotherapy: “A Systematic Review and Meta-analysis”

Abstract

Objective: The objective of this study was to evaluate the effects of the four first premolars extraction compared with a non-extraction treated control group on the lower anterior facial height. Methods: Electronic search was conducted on PubMed, Cochrane, Scopus, Lilacs, Scielo, clinical trials, and opengrey.eu databases; only article published in English were included. The eligibility criteria were extraction of four first premolars compared with a non-extraction control group treated with fixed mechanotherapy. Anterior Nasal Spine to Menton (ANS-Me) (mm) was taken as the primary outcome; Frankfurt mandibular plane angle (FMA) and Nasion to Menton (N-Me) were selected as secondary outcomes. Non-randomized Studies-of Intervention (ROBINS-I) tool was used for the quality assessment and risk of bias. Heterogeneity was analyzed using statistical tests, including chi-squared-based Q-statistic, tau-square, and I-squared statistics. Review Manager was used for quantitative assessment and meta-analysis. Results: Five retrospective studies were included for quantitative assessment and three were included in the meta-analysis due to certain missing data. Extraction of four first premolars did not affect both primary and secondary outcomes with P = .65, P = .93, and P = .91, respectively, for ANS-Me, FMA, and N-Me. Conclusion: This review and meta-analysis concluded that there was no statistically significant effect of extraction of four first premolars on lower anterior facial height.

Cone-Beam Computerized Tomography Evaluation of the Relationship between Orthodontic Vertical Direction Parameters and the Distance from the Apex of the Upper Central Tooth to the Nasal Floor and Anterior Nasal Spine

“…The ANS-Me distance is the most commonly used measurement in orthodontics for the assessment of vertical direction and defines the height of the lower anterior face [ 45 ]. Unlike other measurements in the vertical direction, the ANS-Me distance is a linear distance measurement and is frequently used as a reference in studies [ 46 ]. The reason for comparing ANS-Me and ANS-Gn distances with UA1-ANS and UA1-NF distances in this study is that ANS-Me and ANS-Gn distances are linear distance measurements and commonly used and accepted vertical direction reference parameters.…”