Early and 1-year postsurgical stability and its factors in patients with complicated skeletal Class Ⅲ malocclusion treated by conventional and surgery-first approach: A prospective cohort study

Effects of mandibular setback surgery using the surgery-first approach versus conventional orthognathic approach on upper airway change and sleep quality

OBJECTIVES

To compare the effects of mandibular setback surgery on the upper airway and sleep quality using two approaches: the surgery-first approach (SFA) and the conventional orthognathic approach (COA).

MATERIALS AND METHODS

A prospective, comparative clinical study was conducted in 20 patients, with 10 in each group undergoing isolated mandibular setback surgery. Three-dimensional upper airway analysis using cone-beam computed tomography and sleep quality assessments through questionnaires and sleep studies were performed preoperatively (T0), within 1 month postoperatively (T1), and six months postoperatively (T2).

RESULTS

The SFA group demonstrated greater mandibular setback and rotational changes compared to the COA group. Both groups exhibited postoperative reductions in airway volume and minimum cross-sectional area, with no significant intergroup differences. Significant differences in the change in airway length in the upper airway segment (0.9 ± 1.0 mm for SFA vs. -1.2 ± 3.4 mm for COA, P = 0.002) and total airway length (3.3 ± 1.8 mm for SFA vs. -0.1 ± 2.3 mm for COA, P < 0.001) were observed at T2 compared to the preoperative period. Subjective and objective sleep parameters were comparable between the groups. Objective sleep quality initially worsened but improved over time.

CONCLUSIONS

Isolated mandibular setback surgery, whether performed using SFA or COA, resulted in comparable changes in upper airway dimensions and sleep quality.

CLINICAL RELEVANCE

The choice between SFA and COA for isolated mandibular setback surgery does not significantly influence surgical decision-making regarding upper airway changes and sleep quality.

Three-Dimensional Evaluation of Changes in Condylar Position After Orthognathic Surgery With Different Types of Jaw Deformities

BACKGROUND

Assessing condyle position postorthognathic surgery is pivotal for optimizing surgical accuracy, sustaining postoperative stability, and ensuring predictable treatment outcomes.

PURPOSE

The aim of this study was to analyze the changes of condyle position after orthognathic surgery with different types of jaw deformity and to analyze whether the changes of condyle position are different.

STUDY DESIGN, SETTING, SAMPLE

A retrospective cohort study was designed and conducted, involving adults who underwent orthognathic surgery for jaw deformities at the affiliated Stomatological Hospital of Nanchang University between 2019 and 2022. Patients with incomplete computerized tomography data were excluded.

PREDICTOR/EXPOSURE/INDEPENDENT VARIABLE

The primary predictor variable was time (preoperative and postoperative) and types of jaw deformities (skeletal Class III, skeletal Class II, and mandibular deviation).

MAIN OUTCOME VARIABLE(S)

The main outcome variables were the three-dimensional linear and rotational positional changes of the condyle.

COVARIATES

Evaluated covariates included sex and age.

ANALYSES

MIMICS 20.0 software measured all data, and SPSS 22.0 software facilitated statistical analyses. Intragroup and intergroup correlation analyses employed paired t-tests and independent t-tests, with statistical significance set at P < .05.

RESULTS

The study sample was composed of 32 subjects with a mean age of 22.43 ± 1.6 and 9 were male. The analysis of changes of condylar position from virtual surgical planning to the immediate postoperative period showed that the maximum condylar displacement was 1.74 mm and the maximum angular change was 3.92°. The analysis of changes in condylar position from the immediate postoperative period to 1 year postoperatively showed no statistically significant changes for the same type of jaw deformity. But patients with Class II malocclusion exhibited distinct condylar displacement and rotation patterns compared to those with Class III malocclusion and mandibular deformity.

CONCLUSION AND RELEVANCE

The application of virtual surgical planning in orthognathic surgery ensures a high degree of consistency in achieving the desired condylar position. Moreover, no significant change in condylar position was observed after orthognathic surgery for the same type of jaw deformity. However, patients with Class II deformities exhibited a higher susceptibility to rotational displacement of the condyles compared to those with other types of jaw deformities.

The Skeletal Stability of Combined Surgery First Approach and Clear Aligners in Skeletal Class III Malocclusion Correction: A Randomized Controlled Trial

The surgery first approach (SFA) and clear aligners technique can address traditional treatment defects, such as prolonged waiting times for surgery and a less desirable facial appearance due to wire aligners. However, the curative effect of the combination remains uncertain. The randomized controlled study aimed to evaluate the skeletal stability of the SFA compared to the conventional orthodontic first approach (OFA), both of which were applied with clear aligners. A total of 74 participants were randomly allocated to two groups: the SFA group (experimental) and the OFA group (control). The skeletal deviation was calculated using reconstruction models from computed tomography scans taken immediately and 6 months after surgery. The largest median deviations were detected in the y-axis of the mandible for both two groups, separately 1.36 mm in the experimental group and 1.19 mm in the control group. Apart from the maxillary yaw dimension (p = 0.005), there were no significant differences between the two groups in terms of linear and angular deviation. The experimental group had an overall treatment time of 18.05 ± 2.53 months, while the control group took 22.83 ± 3.60 months (p < 0.05). Therefore, the combined surgery-first and clear aligners treatment can achieve comparable skeletal stability to the conventional approach, while also saving significant time.