Comparing Effects of Bone-anchored and Tooth-anchored Maxillary Expanders on Adolescents

Abstract

<p><strong>Objectives:</strong> This systematic review and meta-analysis were performed to compare the difference in the three-dimensional (3D) skeletal and dentoalveolar effects of bone-anchored (BA) and tooth-anchored (TA) maxillary expanders in growing patients.</p><p><strong>Methods:</strong> A systematic literature search was conducted across four electronic databases to identify randomized clinical trials (RCTs) that evaluated skeletal and dentoalveolar changes in adolescents after BA and TA expansion using 3D radiographic images. Following risk of bias assessment and data extraction, meta-analyses were performed for comparations between BA and TA for skeletal effects regarding changes in sutural expansion (SE), nasal width (NW), and maxillary width (MW), as well as dentoalveolar effects including tooth inclination (TI) and buccal bone thickness (BBT) changes of the first premolar and first molar using random-effect models. Comparisons were made using standard mean difference (SMD) at three timepoints: immediately after expansion, within 6 months and beyond 6 months after expansion.</p><p><strong>Results:</strong> Ten studies were included in this systematic review, with nine pooled for quantitative synthesis. Immediately after expansion, BA showed greater SE (0.77-1.50), NW (0.60-0.85), and MW (0.51-1.06) than TA, with slightly less changes in TI (0.30-1.52) and BBT (0.16-0.83) at the first molar. Short-term effects favoured BA expanders over TA in both skeletal and dentoalveolar measurements, with SE (0.27-1.12), NW (0.97-1.18), MW (0.46-0.59), TI (0.22-1.77), and BBT (0.68-1.29). Only two studies examined long-term effects, showing no significant difference in SE and MW, though BA demonstrated greater skeletal effect on NW (0.63, 95% CI: 0.19-1.08) than TA.</p><p><strong>Conclusion:</strong> Current evidence demonstrates that BA expanders yield superior skeletal effects and reduced adverse dentoalveolar effects compared to TA during immediate and short-term periods. However, evidence evaluating their effects beyond 6 months after expander removal remains sparse, with only NW showing potentially greater increase with BA.</p>