Three-Dimensional Volumetric Assessment of Root Resorption in Rapid Maxillary Expansion: A Meta-Analysis Comparing Tooth-Borne and Bone-Borne Devices

Abstract

To compare the extent of root resorption, assessed via three-dimensional (3D) volumetric CBCT analysis, between tooth-borne and bone-borne rapid maxillary expansion (RME) devices. A systematic search of seven databases (PubMed, Cochrane Library, Embase, etc.) up to December 2024 identified eligible studies (randomised controlled trials, cohort studies, clinical trials) evaluating CBCT-measured root resorption in patients treated with tooth-borne, bone-borne or hybrid RME devices. Data were analysed using STATA 17.0, employing weighted mean differences (WMDs) and random/fixed-effects models. Heterogeneity, subgroup analyses and publication bias were assessed. Sixteen studies (525 patients, 2906 teeth) were included. These studies comprised randomised controlled trials and observational studies, predominantly enrolled adolescent and young adult patients, and directly compared tooth-borne and bone-borne RME devices. Tooth-borne RME resulted in significantly greater root resorption volume compared to bone-borne devices (WMD = −10.4 mm³, 95% CI [−13.9, −6.9], 95% prediction interval [−11.94, −8.92], p < 0.05; I² = 98.8%). Tooth-borne RME also caused greater root length loss (WMD = −0.14 mm, 95% CI [−0.21, −0.08], 95% prediction interval [−0.20, −0.08], p < 0.05; I² = 95.6%). Tooth-borne RME resulted in significantly greater root resorption volume (WMD = −20.7 mm³) and length (WMD = −0.40 mm) compared to baseline, indicating increased resorption. Three-dimensional CBCT analysis demonstrated superior sensitivity in detecting resorption morphology and localization compared to linear measurements. Bone-borne RME devices, which are associated with reduced root resorption risks, may be related to improved force distribution to bony structures. Three-dimensional volumetric CBCT assessment provides a more accurate quantification than linear measurements. Clinically, bone-borne expanders are recommended for high-risk patients, while tooth-borne users require close CBCT monitoring. Findings should be interpreted considering limitations of the included evidence, including heterogeneity in RME devices and protocols, risk of bias in some non-randomised studies, and imprecision due to limited sample sizes in subgroup analyses and lack of long-term data.

Trial Registration: International Prospective Register of Systematic Reviews (PROSPERO) registration number: CRD420251018535