A non-cephalometric three-dimensional appraisal of soft tissue changes by functional appliances in orthodontics: a systematic review and meta-analysis.

BACKGROUND: Patients with dental and skeletal Class II growth patterns present typical facial characteristics. Functional appliance (FA) therapy is one of the conventional orthodontic treatment modalities used to harmonize these facial imbalances. OBJECTIVES: The aim of this systematic review was to investigate and summarize the effects of FAs on the facial soft tissues captured in three dimensions. SEARCH METHODS: A systematic search was conducted up to December 2020. Databases Medline (via PubMed), Embase (via Ovid), Web of Science, and Cochrane Central were searched without language restrictions. SELECTION CRITERIA: Randomized clinical trial (RCT)'s investigating the influence of FA therapy on the facial soft tissues in a non-cephalometric and three-dimensional (3D) manner, were included. DATA COLLECTION AND ANALYSIS: Data extraction was independently undertaken by two authors. In case of conflict, a third author was consulted. RoB 2.0 tool was used to assess the risk of bias. A meta-analysis was performed for total facial height, upper lip length, lower lip length, commissural width, and facial depth. The single-step activation versus incremental approach was compared using a random effects model. RESULTS: Five studies were included in the qualitative synthesis of the systematic review. Facial height increased after FA therapy. Three studies met the criteria for the meta-analysis. The mean facial depth increased significantly (P < 0.003) with 1.39 mm (0.46 to 2.32). CONCLUSIONS: Current evidence suggests a positive influence of the FA therapy on the soft tissues in Class II patients. However, conclusions were drawn based on a two-dimensional analysis of 3D images, suggesting that more controlled studies using a comprehensive 3D analysis are necessary to confirm these results. REGISTRATION: PROSPERO registration (CRD 42021224016).

A non-cephalometric two-dimensional appraisal of soft tissue changes by functional therapy in Class II patients: a systematic review and meta-analysis.

BACKGROUND: Facial attractiveness has social, psychological, and economic repercussions. Class II malocclusions are associated with a retroposition of the mandible, facial convexity, protruded upper lip, retruded lower lip, and pronounced mentolabial fold. Functional appliances (FA) try to increase mandibular length and normalize lip position, thereby decreasing the facial profile convexity and aesthetics. OBJECTIVES: The aim of this review and meta-analysis is to investigate the effects of FA on the soft tissues in a non-cephalometric two-dimensional manner. SEARCH METHODS: Medline (via PubMed), Embase (via Ovid), Web of Science, and Cochrane Central were used to identify studies describing the soft tissue results of FA in a non-cephalometric way. The search was conducted up to July 2021. SELECTION CRITERIA: Prospective and retrospective studies investigating the effects of FA appliances on the soft tissues, with non-ionizing, two-dimensional imaging, including an attractiveness assessment based on Visual Analogue Scale or Likert scale, were considered eligible. DATA COLLECTION AND ANALYSIS: Data extraction was performed separately by two authors. Risk of bias was assessed using the ROBINS-I tool. RESULTS: From the eight eligible studies, four were included in the meta-analysis to investigate the influence of assessors on facial attractiveness scores. Age range of the included studies varied from 8 to 21 years old including 313 Caucasian patients whereof 64% females. Six out of eight studies used growing patients as treatment group and only two studies reported follow-up after the end of treatment. Overall facial attractiveness increased after treatment with FA, resulting from a decrease in facial convexity and a normalization of the lip relationship. Orthodontists score higher aesthetic improvements after FA treatment as compared to laypeople. CONCLUSIONS: Current evidence suggests the positive effects of FA on the facial attractiveness in growing and non-growing patients. FA normalize the lip relationship. Furthermore, they tend to decrease facial convexity and advance the chin point. More pleasing results can be expected in growing patients. Orthodontists are more generous when assessing treatment changes as compared to laypeople. REGISTRATION: PROSPERO registration (CRD42021254835).