Orthodontic Retainers and the Stability of the Maxillary Arch in Unilateral Cleft lip and Palate Patients: A Systematic Review

Objective The aim of this systematic review was to elucidate the role of orthodontic retainers on the stability of compensatory orthodontic treatment in patients with unilateral cleft lip and palate. Methods Five electronic databases (PubMed, Scopus, Web of Science, LILACS, and LIVIVO) and the grey literature (OpenGrey and Google Scholar) were investigated, according to the population, exposure, comparator, outcomes and Study design eligibility criterion. The risk of bias assessment was determined based on the Risk of Bias In Nonrandomized Studies of Exposure (ROBINS-E) and the level of evidence with the GRADE tool. Results Three studies were included: two presented moderate risk of bias and one high. A moderate level of evidence revealed a mean value of 0.6 mm of intercanine relapse distance, and great variability between the data, regardless of the use or type of retention or rehabilitation. Relapse in the posterior region showed clinical significance, from -1 to -1.7 mm, especially in individuals who did not use retention, except in patients with symmetrical arches with Hawley retainer, where this value varies from -0.2 +/- 0.63 mm. Conclusions Orthodontic retainers do not seem essential to prevent relapse at anterior maxillary dimensions after compensatory orthodontic treatment in patients with unilateral cleft lip and palate. Relapse in the posterior region can achieve greater clinical significance, which highlights the need for prolonged use of Hawley retainers and periodic evaluation of the stability of treatment results. Prospective studies with a longer follow-up can improve the certainty of the evidence.