RESUMO
OBJECTIVE: A critical analysis of the literature to determine the prevalence and type of emergency/additional appointments, and discomfort levels associated with fixed Class II correctors. METHODS: Studies examining patient's sources of discomfort or emergency appointments associated with compliance-free Class II correctors were included. Comprehensive searches up to July 2018 were conducted using the following databases: MEDLINE (OvidSP), PubMed, Web of Science, and Embase. A partial grey literature search was taken using Google Scholar and OpenGrey. Two reviewers independently performed the selection process and risk of bias assessment. The Newcastle-Ottawa Scale for cross-sectional studies were used. A summary of the overall strength of evidence was presented using 'Grading of Recommendations, Assessment, Development and Evaluation' (GRADE) tool. Included studies were evaluated according to their design, study quality, consistency, and directness. RESULTS: The selected studies were published between 2001 and 2018, and the number of patients per studied group ranged from 8 to 182. One thousand five hundred forty-two patients were evaluated in total. The patients' mean age at start of treatment ranged from 10 to 16.9 years and the fixed Class II corrector treatment duration ranged from 4 to 12 months. The included studies in this systematic review were too clinically heterogeneous (different appliances, different data recollection processes) to justify a meta-analysis. LIMITATIONS: This review was not previously registered. A low level of evidence was observed among the two randomized trials, the 10 cohorts and three cross-sectional studies identified. CONCLUSIONS: The main source of discomfort from Forsus-type appliances appears to be soreness in the cheeks (low level of evidence with a weak recommendation strength). Most evaluated patients treated with a Herbst appliance, regardless of design, will experience complications (fractures and/or dislodging) requiring emergency appointments (low level of evidence with a weak recommendation strength). REGISTRATION: The review protocol was not registered.