Mandibular Advancement and Skeletal Anchorage in Class II Malocclusion Patients: A Systematic Review with Meta-Analysis

Abstract

(1) Objectives: The purpose of this review was to compare the effects of combining skeletal anchorage and Class II devices, both from an overall perspective and individually for each type of appliance, considering as main outcomes the vertical dimensions and the inclination of the mandibular and maxillary incisors. (2) Materials and Methods: A search without time restrictions was performed up to February 2024 in PubMed, PubMed Central, Scopus, and Medline for randomized controlled trials, as well as prospective and retrospective cohort studies, considering Class II patients treated with and without skeletal anchorage. The effect measure used for the meta-analytic evaluation was the standardized mean difference (SMD). The SMD calculation was obtained by subtracting the mean values of T1–T0 for each individual treatment and then calculating the SMD between the treatments involved. The meta-analysis was performed using the standardized mean difference of the mean difference of the T1–T0 change in the outcome between the different treatments evaluated as the effect size. (3) Results: A total of 1217 documents were initially retrieved. According to the PRISMA protocol, 18 studies comparing different skeletal anchorage protocols (upper/lower miniscrews and miniplates), combined with four appliances (Herbst, Forsus, Carriere Motion, and elastics), were included in the analysis. No significant difference in skeletal divergence was found between groups from an overall point of view (SMD: 0.19 (−0.48 to 0.83) according to the random-effects model). A statistically significant reduction in IMPA° was found in patients treated with temporary anchorage devices (TADs) (SMD of 5.58 (3.40 to 7.75)), except for the elastics group (SMD: 3.76 (−0.91 to 8.43)). The effect on the upper incisors’ inclination appeared to be strictly dependent on the type of anchorage (TADs in one or both of the arches). Some limitations must be considered when interpreting the results: the small number of studies included and the heterogeneity among them are among the limitations, and the temporal disparity among some studies; the ages of the patients were not always comparable; and, finally, the clinical relevance of the effects of TADs is sometimes questionable. (4) Conclusions: The vertical dimension seems not to be significantly affected by skeletal anchorage; instead, the proclination of mandibular incisors is generally reduced when TADs are used. Skeletal anchorage might be useful if lingual tipping of the upper incisors is required; however, it is influenced by the anchorage protocol.