Premolar extraction in orthodontics: Does it have any effect on patient′s facial height?

Abstract

Objectives:Facial esthetics is an important part of the orthodontic treatment. Many cases frequently require premolar extraction, either for relief of crowding or for profile change. Supposedly, extraction provides some vertical reduction. This investigation challenges the clinical effects of such treatment protocols.Patients and Methods:This was a retrospective and quasi-experimental study. Records of 60 patients in their post-pubertal age were randomly selected for this study. The criteria for case selection were: Class II Division I malocclusion with either two upper or four upper and lower first premolars extraction. Patients were not vertical-sensitive type of face. Pre- and post-treatment X-rays were scanned and digitized with Dolphin V 10.0 software. The X-rays of both groups were compared based upon the following cephalometric measurements: Lower anterior facial height (LAFH), Me–PP, Pal-MeGe, LAFH/total anterior facial height (TAFH) × 100, upper anterior facial height (UAFH)/TAFH × 100, U6 to PP, L6 to MP, and U6D–PTV.Results:In the four bicuspid group, a statistically significant increase was observed in all measurements: 2.53 mm increase in LAFH (P ≤ 0.04), 2.92 mm increase in Me–PP (P ≤ 0.01), 0.65° increase in Pal-MeGe (P ≤ 0.02), 0.66° increase in LAFH/TAFH × 100 (P ≤ 0.01), 1.26 mm increase in U6 to PP (P ≤ 0.02), 1.96 mm increase in L6 to MP (P ≤ 0.002), and 3.06 mm increase in U6D–PTV (P ≤ 0.0001). But a decrease of 0.66° in UAFH/TAFH × 100 (P ≤ 0.01) was observed. In the two bicuspid group, a significant increase was generally recorded: 2.06 mm increase in LAFH (P ≤ 0.05), 1.19° increase in Pal-MeGe (P ≤ 0.02), 1.39 mm increase in L6 to MP (P ≤ 0.002), and 2.37 mm increase in U6D–PTV (P ≤ 0.004).Conclusions:The results of this study are indicative of no change in patient's facial height with bicuspid extraction. In fact, extrusive effect of all types of tooth movement mostly overcomes the benefits of “wedging effect concept.”

Comparison of soft and hard tissue changes between symmetric and asymmetric extraction patterns in patients undergoing orthodontic extractions

“…These findings are in concordance with the study conducted by Zafarmand and Zafarmand, where the bicuspid extraction theory (neither 2 nor 4 premolar extractions) for reducing the facial height did not provide any significant changes post-treatment. 36 The vertical angle and the lower anterior facial height increased in both of their groups. This was also highlighted in a study conducted by Staggers, according to whom the biomechanical justification for this could be the intrinsic extrusive effect of most orthodontic modalities, e.g., the protraction of posterior teeth, which can unfavorably compensate any reduction in the facial height.…”

Effect of High Molecular Nano-Chitosan Addition on The Impact Strength of Heat Polymerized Polymethyl Methacrylate Denture Base Resin

“…Several previous studies have shown that changes in relation between the size of the teeth and the length of the curve are multifactorial, depending on the overbite, the overjet, the inclination of the anterior teeth, the intercanine width, the intermolar width, the curve width, and the curve of Spee [9].…”

Evaluation of Lower Anterior Facial Height and Incisors Vertical Dimension after Class II Division 1 Treatment

“…6,7,8 Cusinamo et al suggested that premolar extraction did not increase facial height. 9,10 Instead, research conducted by Wyatt proved that premolar retraction followed by anterior teeth retraction in orthodontic treatment of class II division 1 malocclusion might cause posterior displacement of the condyle and disc transfer into the anterior thus causing vertical dimension changes.…”

“…Based on the above descriptions we are interested in researching the vertical dimension changes of lower anterior facial height and incisors in class II division 1 malocclusion orthodontic treatment with Edgewise technique by extraction of two maxillary premolars. 9,10…”