Three-dimensional cephalometric outcome predictability of virtual orthodontic-surgical planning in surgery-first approach

Enhancing skeletal stability and Class III correction through active orthodontist engagement in virtual surgical planning: A voxel-based 3-dimensional analysis

INTRODUCTION

Skeletal stability after bimaxillary surgical correction of Class III malocclusion was investigated through a qualitative and quantitative analysis of the maxilla and the distal and proximal mandibular segments using a 3-dimensional voxel-based superimposition among virtual surgical predictions performed by the orthodontist in close communication with the maxillofacial surgeon and 12-18 months postoperative outcomes.

METHODS

A comprehensive secondary data analysis was conducted on deidentified preoperative (1 month before surgery [T1]) and 12-18 months postoperative (midterm [T2]) cone-beam computed tomography scans, along with virtual surgical planning (VSP) data obtained by Dolphin Imaging software. The sample for the study consisted of 17 patients (mean age, 24.8 ± 3.5 years). Using 3D Slicer software, automated tools based on deep-learning approaches were used for cone-beam computed tomography orientation, registration, bone segmentation, and landmark identification. Colormaps were generated for qualitative analysis, whereas linear and angular differences between the planned (T1-VSP) and observed (T1-T2) outcomes were calculated for quantitative assessments. Statistical analysis was conducted with a significance level of α = 0.05.

RESULTS

The midterm surgical outcomes revealed a slight but significantly less maxillary advancement compared with the planned position (mean difference, 1.84 ± 1.50 mm; P = 0.004). The repositioning of the mandibular distal segment was stable, with insignificant differences in linear (T1-VSP, 1.01 ± 3.66 mm; T1-T2, 0.32 ± 4.17 mm) and angular (T1-VSP, 1.53° ± 1.60°; T1-T2, 1.54° ± 1.50°) displacements (P >0.05). The proximal segments exhibited lateral displacement within 1.5° for both the mandibular right and left ramus at T1-VSP and T1-T2 (P >0.05).

CONCLUSIONS

The analysis of fully digital planned and surgically repositioned maxilla and mandible revealed excellent precision. In the midterm surgical outcomes of maxillary advancement, a minor deviation from the planned anterior movement was observed.

Is there a difference in surgical accuracy following bimaxillary surgery between cleft and non-cleft patients?

OBJECTIVES

To assess the surgical accuracy of 3D virtually planned orthognathic surgery among patients with and without cleft.

MATERIALS AND METHODS

This retrospective cohort study included cleft and non-cleft patients with class III malocclusion who underwent bimaxillary surgery. CBCT scans were acquired before and immediately after surgery. 3D virtual surgical planning (VSP) was performed using CBCT and digitalized dentition data. All orthognathic surgeries were performed by the same surgeons using interocclusal splints. The primary outcome variable was surgical accuracy, defined as the difference between the planned and surgically achieved maxillary movements, quantified in six degrees of freedom. Analysis of covariance was used to test for intergroup differences in surgical accuracy after correcting for differences in the magnitude of planned surgical maxillary movements.

RESULTS

Twenty-eight cleft and 33 non-cleft patients were enrolled, with mean ages of 18.5 and 25.4 years, respectively (P=0.01). No significant gender difference was present between the groups (P=0.10). After adjustment for small differences in surgical movements, no significant differences in surgical accuracy were observed between cleft and non-cleft patients.

CONCLUSION

The present study demonstrates that high surgical accuracy in maxillary movements can be achieved in both cleft and non-cleft patients using VSP and interocclusal splints.

CLINICAL RELEVANCE

Orthognathic cases with cleft can be performed with 3D VSP to obtain a satisfactory surgical accuracy.