The Impact of Extraction vs Nonextraction Treatment on Soft Tissue Profile in Borderline Class I Malocclusion: A Cephalometric Study

Abstract

Introduction: The continuous controversy concerning extraction of premolar teeth and its supposed effects on the facial profile led to the origin of this study, which compares the pretreatment and post-treatment facial profiles of patients who underwent premolar extraction with those of patients who did not undergo extraction. Objective: To analyze the soft tissue changes between the two different treatment groups, equally susceptible to both treatment options (extraction and nonextraction) and to compare the changes taking place in the soft tissue variables from one group to another using the cephalometric analysis. Materials and methods: The diagnostic extraction and treatment decisions were based on a total space analysis with differential extraction protocols. The pretreatment and posttreatment cephalograms of the borderline sample (100 female patients, 50 of the patients were treated with premolar extraction and 50 were treated without premolar extraction) were then subjected to a thorough soft tissue cephalometric analysis. Results: The results indicated that the three variables that played the most important role in the clinician’s treatment decision were indicators of lower crowding, soft tissue convexity and lower incisor protrusion. Significant differences (p < 0.05) regarding upper and lower lip protrusion, upper lip thickness (p < 0.05) and the nasolabial angle (p < 0.05) occurred after treatment. Conclusion: Extraction treatment of Class I borderline malocclusions led to significant soft tissue changes in relation to the upper and lower lip position and thickness as well as the nasio labial angle, whereas the nonextraction treatment resulted in significant upper lip retraction and lower lip protraction.