Soft-tissue changes following fixed orthodontic treatment with premolar extractions in patients with Class I and II malocclusions: A scoping review

This study synthesized the scientific evidence on soft-tissue changes following fixed orthodontic treatment with premolar extractions in patients with Class I and II malocclusions. A scoping review was conducted to achieve this, collecting articles from previous research. A comprehensive search was performed in the PubMed, ScienceDirect, and Web of Science databases, focusing on original studies published between 1993 and 2023. The main characteristics of the included publications were analyzed. As a result, eight studies met the inclusion criteria. The findings indicated that premolar extractions significantly influenced soft-tissue profiles, particularly by increasing the nasolabial angle and reducing lip protrusion. In Class I malocclusions, extractions improved facial harmony but posed a risk of over-retraction in thin-lipped patients. In Class II malocclusions, extractions effectively reduced upper lip prominence and convexity, although excessive retraction could occasionally lead to a flattened profile. Eighty-one percent of cases demonstrated positive soft-tissue changes, while 19% exhibited drawbacks such as over-retraction and limited effectiveness in addressing skeletal discrepancies. In conclusion, premolar extractions significantly modify soft-tissue esthetics, with outcomes varying based on facial type and treatment mechanics. However, variability in study methodologies and individual responses highlights the need for personalized treatment planning. Further research with standardized protocols and long-term follow-ups is recommended to optimize treatment outcomes.