Extraction versus non-extraction: evaluation by digital subtraction radiography

Abstract

The aim of this study was to investigate the facial profile changes of patients treated with and without extractions of four first premolars using novel computer-based digital subtraction software. The pre- and post-treatment radiographic image pairs of 25 extraction (13 girls and 12 boys, mean age = 12.64 +/- 1.82 years) and 24 non-extraction (12 girls and 12 boys, mean age = 12.48 +/- 1.66 years) Class I patients were subtracted by the software. Student's t-tests were used to determine whether the subtraction values for the linear measurements of radiographic differences registered at various anatomical landmark parameters were statistically different between the groups. To further determine whether any variables related to upper and lower lip changes, regression analyses were performed. The main soft tissue differences between the groups were established at labrale superior, labrale inferior, and sulcus inferior points, with extraction patients showing significantly more retruded upper and lower lips. However, the mean differences between the groups did not exceed 1 mm for these variables. Changes at labrale superior and labrale inferior were associated with sagittal movement of the maxillary (r = 0.549) and mandibular (r = 0.630) incisor midpoints. Changes at sulcus inferior were associated with both sagittal and vertical displacement of mandibular incision point (r = 0.676). Some dentofacial alterations were found but in view of the differences between the groups pretreatment, the inter-group differences reflect different treatment intent rather than differences arising from the extraction and non-extraction modalities.

Associations between orbicularis oris thickness and skeletal and dental variables in mixed dentition

“…Studies have shown that the upper and lower lips move slightly posteriorly following an orthodontic treatment with extractions 16,17 since the soft tissue may be associated with sagittal changes in both the maxillary and mandibular incisor position 16 . However, changes in the soft facial profile also seem to be related to other variables, such as lip strain, structure, and thickness, together with incisor retraction 18 .…”

European Position on Clinical Practice of Extraction and Nonextraction Therapy in Orthodontics

“…The basal angle and the angle of the lower jaw remain unchanged, the facial angle decreases, the profile of the face looks like node and more harmonious. Extraction of the first premolars leads to changes in soft tissues: the size of the tongue decreases, the thickness of the lips changes, which does not depend on gender [10], however with age, age-related changes occur in patients with class I pathology, orthodontically treated with tooth extraction, every 10 years the ratio between upper frontal teeth and lips decreases by 1 mm, lips flatten, and ∠ ANL increases by 2 ° [1]. Comparative analysis of the profile characteristics of orthodontic patients confirmed that extraction therapy should not be avoided, since aesthetic profile changes are minimal (without gender differences) both in the treatment with removal of premolars and in the treatment without extraction [31,32,28].…”

Dentoskeletal and soft tissue changes after treatment of crowding with premolar extractions: a 50-year follow-up

“…Some studies have reported no significant differences between the extraction and non-extraction orthodontic treatment outcomes ( 10 , 11 , 15 , 16 ). However, other studies have found that premolar extraction can affect the dentoskeletal and soft tissue profile ( 7–9 , 12 ). Possible reasons for these discrepant results are differences in the study designs and inadequate control groups.…”

“…Several studies have evaluated the effects of extractions and subsequent orthodontic treatment on craniofacial changes ( 7–16 ). Some studies have reported no significant differences between the extraction and non-extraction orthodontic treatment outcomes ( 10 , 11 , 15 , 16 ).…”

“…As a consequence of the current aesthetic ideal, whereby patients favour fuller lips, non-extraction orthodontic treatment options have become more popular. The potential changes in lip position following premolar extraction and incisor retraction ( 7 , 8 ) may jeopardize the aesthetics. As a result, orthodontists are reluctant to choose extraction treatment to relief crowding.…”