Comparison of dynamic high-frequency ultrasound-guided versus conventional manual determination of mandibular protrusion in the treatment of disc displacement with reduction: a prospective, stratified randomized controlled trial.

OBJECTIVES

To compare the clinical and radiographic outcomes of dynamic high-frequency ultrasound guidance versus conventional manual techniques for determining the mandibular protrusive position of anterior repositioning splints (ARS) in the treatment of disc displacement with reduction (DDwR).

MATERIALS AND

METHODS

This prospective randomized controlled trial included 40 patients with DDwR, who were randomly and equally divided into an ultrasound-guided group (US-ARS) and a conventional manual group (M-ARS). Both groups received customized ARS therapy. At baseline and 3 months post-treatment, cone-beam computed tomography (CBCT) was used to evaluate joint spaces and condylar bone characteristics, while magnetic resonance imaging (MRI) was used to measure the disc-condyle angle and disc morphology.

RESULTS

After 3 months of treatment, there were no significant inter-group differences regarding the increase in CBCT joint spaces and the improvement in condylar bone scores (P > 0.05). However, in the MRI soft-tissue evaluation, the US-ARS group demonstrated a significantly greater reduction in the disc-condyle angle (-20.50° ± 7.50° vs. -12.00° ± 8.50°, P = 0.002) and a superior improvement in the disc morphology score (P = 0.001) compared to the M-ARS group.

CONCLUSIONS

Compared to conventional empirical manual techniques, ultrasound guidance provides a more precise determination of the magnitude of mandibular protrusion. This achieves superior three-dimensional articular disc reduction and morphological remodeling at the soft-tissue level while maintaining equivalent hard-tissue decompression efficacy.

TRIAL REGISTRATION: MR5124001996.