Surgery-first orthognathic approach for the correction of facial asymmetry

Panoptic evaluation of maxillomandibular stability and quality of life after surgery-first approach versus conventional three-stage method in skeletal Class III orthognathic surgery-systematic review and meta-analysis

This study was performed to comprehensively evaluate the outcomes of the surgery-first approach (SFA) compared to the conventional three-stage method (CTM) in skeletal Class III deformity patients, in terms of stability, quality of life, and treatment time. The search covered the period 2010-2022. Heterogeneity was assessed and the stability was subgroup analysed into two-jaw and one-jaw surgery. Thirty-three studies were identified, 29 were included in the meta-analyses. Overall anteroposterior stability of the maxilla and mandible did not differ significantly between CTM and SFA groups (maxilla, P = 0.77; mandible, P = 0.072). In two-dimensional radiographs, the results for anteroposterior stability of the mandible were in favour of CTM (P = 0.051); conversely, vertical stability of the mandible showed better results with SFA (P = 0.051). SFA patients showed a significantly shorter treatment time (P < 0.001) and better quality of life (22-item Orthognathic Quality of Life Questionnaire) at 6 months follow-up (P = 0.042). In conclusion, CTM supports better anteroposterior stability. Nevertheless, SFA provides greater vertical stability in the mandible and is associated with a shorter treatment time and better quality of life. However, only six of the 33 included studies were randomized controlled trials, hence in view of the weakness of the evidence, the results should be interpreted with caution.

A Novel Method of Correcting Lower Facial Asymmetry: Computer-Assisted Surgery with Contralateral Mandibular Outer Cortex Sandwich Grafting

BACKGROUND

Lower facial asymmetry often results in an esthetically unpleasing appearance. The purpose of this study was to develop a novel method for correcting lower facial asymmetry using mandibular augmentation with sandwich bone grafts from the contralateral mandibular outer cortex (MOC), and to evaluate the efficacy of this method using computer-assisted techniques.

METHODS

The medical records of 16 patients with lower facial asymmetry who underwent mandibular augmentation with sandwich bone grafts from the contralateral MOC between January 2016 and December 2019 were retrospectively reviewed. Preoperative computer-aided design (CAD) was performed based on CBCT data, MOC grafts were harvested from the donor side using a 3D printed osteotomy guide template and grafted to the recipient side in sandwich manner to augment the contralateral mandible. Effectiveness was evaluated through pre- and postoperative CBCT data and FACE-Q questionnaire scores. Neurosensory recovery of the inferior alveolar nerve was assessed using the functional sensory recovery (FSR) scale.

RESULTS

All procedure were successfully completed, and the asymmetry was effectively corrected three-dimensionally with no serious complications. The patients' FACE-Q scores for satisfaction with the lower facial area significantly increased from 52.19±7.51 to 86.69±7.50. No significant differences were observed in the pre- and postoperative lengths of mandibular ramus or body on either side. The donor site volume increased by 559.38±335.12 mm3 at 6 months postoperatively. The recipient site volume increased by 4415.94±1017.21 mm3 on the 7th day postoperatively and decreased by 202.63±300.85 mm3 at 6 months, reflecting a bone resorption rate of 5.67 ± 8.12%. The median FSR time for the chin and lower lip was 90 days.

CONCLUSIONS

Mandibular augmentation with contralateral MOC sandwich grafts effectively increases mandibular width and volume with a low resorption rate. This method allows for three-dimensional restoration of facial symmetry in cases of mild to moderate lower facial asymmetry, achieving a harmonious and symmetric appearance.

LEVEL OF EVIDENCE IV

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Gearing Effect in Clockwise Rotational Orthognathic Surgery

BACKGROUND

The standard procedure for managing skeletal class III malocclusion is maxillary advancement with mandibular setback. Occlusal plane-altering orthognathic surgery, such as jaw rotation, is useful as well. Although clockwise jaw rotation is a common procedure, its mechanism has not been well investigated. With this study, the authors aim to introduce the gearing effect to correct class III malocclusion in Asians by maxillary posterior impaction using clockwise rotation without advancing the maxilla.

METHODS

Patients with class III correction with clockwise rotation of the maxillomandibular complex without maxillary advancement were included; those who underwent genioplasty were excluded. Various facial skeletal cephalometric landmarks were measured using artificial intelligence-based cephalometric analysis software. The gearing effect was determined by dividing the lower anterior facial height (LAFH) in relatively short and long groups compared with those in the anterior nasal spine to posterior nasal spine length.

RESULTS

In a total of 29 patients, the amount of menton setback between group 1 ( n = 15; short LAFH) and group 2 ( n = 14; long LAFH) was 1.67 ± 0.66 and 2.74 ± 0.99 mm per 1 mm of posterior nasal spine impaction, respectively ( P = 0.002), and 1.58 (interquartile range, 0.78) and 1.95 (interquartile range, 1.05) mm per 1 degree of clockwise rotation of the palatal angle, respectively ( P = 0.007). The convexity of the A point was improved without any significant change in the sella-nasion-A point angle before and after surgery.

CONCLUSIONS

This article addresses the scientific evidence regarding the impact of clockwise rotational orthognathic surgery based on the gearing effect. The mandibular setback turned out to be more effective in patients with a long LAFH.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Risk, II.

Correcting facial asymmetry through guided plate assisted mandibular angle osteotomy

Background

Asian women prefer a smooth and narrowed mandibular appearance. The purpose of the retrospective cohort study is to evaluate guide plate-assisted mandibular angle ostectomy (MAO) in improving mandibular symmetry for Asian female patients with mandibular angle hypertrophy (MAH) with normal occlusal relationship.

Methods

We retrospectively examined 11 patients with asymmetry MAH with normal occlusal relationship who received MAO at Shanghai Ninth People's Hospital between September, 2020, and January, 2022. Preoperative plans were designed based on CT data and executed using metal guide plate during the operation. Preoperative and one-week postoperative CT scans were used to assess measurements including Height_Go, Divergence_Go, ∠ZyZy-GoGo, and osteotomy volume, to evaluate symmetry. For precision, compare the postoperative CT with the preoperative design, assessing osteotomy distance, angle, and volume error. Patient satisfacation was evaluated with Likert Scale in 6-month follow-up. Secondary lipofilling procedures were given as appropriate. Statistical analysis was performed using paired t-tests in SPSS.

Results

The mean age of the 11 patients was 28.5 years (range 23-34 years). 2 of these underwent lipofilling procedures. No complications were observed during the following-up. Postoperative results were not statistically different from the design, demonstrating a precision of within 2 mm. Height_Go disparity within 5 mm get corrected notably, reducing asymmetry from 15.09% preoperatively to 2.74% postoperatively. Patients satisfaction was rated at 4.5 out of 5 in 6 month follow-up.

Conclusions

Guide plate-assisted mandibular angle osteotomies achieve effective and precise surgery. This approach demonstrates a safe option for correction for mandibular asymmetry, achieving patient satisfaction.

Morpho-functional analysis of the temporomandibular joint following mandible-first bimaxillary surgery with mandible-only patient-specific implants

The aim of this study was to evaluate condylar and glenoid fossa remodeling after bimaxillary orthognathic surgery guided by patient-specific mandibular implants. In total, 18 patients suffering from dentofacial dysmorphism underwent a virtually planned bimaxillary mandibular PSI-guided orthognathic procedure. One month prior to surgery, patients underwent a CBCT scan and optical scans of the dental arches; these datasets were re-acquired 1 month and at least 9 months postsurgery. Three-dimensional models of the condyles, glenoid fossae, and interarticular surface space (IASS) were obtained and compared to evaluate the roto-translational positional discrepancy and surface variation of each condyle and glenoid fossa, and the IASS variation. The condylar position varied by an average of 4.31° and 2.18 mm, mainly due to surgically unavoidable ramus position correction. Condylar resorption remodeling was minimal (average ≤ 0.1 mm), and affected skeletal class III patients the most. Later condylar remodeling was positively correlated with patient age. No significant glenoid fossa remodeling was observed. No postoperative orofacial pain was recorded at clinical follow-up. The procedure was accurate in minimizing the shift in relationship between the bony components of the TMJ and their remodeling, and was effective in avoiding postoperative onset of orofacial pain. An increase in sample size, however, would be useful to confirm our findings.

3D facial mask for facial asymmetry diagnosis

Objectives

Facial asymmetry is a common problem seen in orthodontic clinics that may affect patient esthetics. In some instances, severe asymmetry that affects patient esthetics may cause psychological issues. An objective method is therefore required to help orthodontists identify asymmetry issues.

Materials and methods

We used three-dimensional (3D) facial images and landmark-based anthropometric analysis to construct a 3D facial mask to evaluate asymmetry. The landmark coordinates were transformed using a symmetric 3D face model to evaluate the efficacy of this method. Patients with facial asymmetry were recruited to conduct mirror and overlap analysis to form color maps, which were used to verify the utility of the novel soft tissue landmark-based method.

Results

The preliminary results demonstrated that the asymmetry evaluation method had a similar response rate compared to diagnosis using mirror and overlap 3D images, and could therefore identify 3D asymmetry problems.

Conclusions

By using 3D facial scans and 3D anthropometric analysis, we developed a preliminary evaluation method that provides objective parameters to clinically evaluate patient facial asymmetry and aid in the diagnosis of asymmetric areas.

Clinical relevance

This study presents a novel facial asymmetry diagnostic method that has the potential to aid clinical decisions during problem identification, treatment planning, and efficacy evaluation.

Current Trends in Orthognathic Surgery

Orthognathic surgery has evolved significantly over the past century. Osteotomies of the midface and mandible are contemporaneously used to perform independent or coordinated movements to address functional and aesthetic problems. Specific advances in the past twenty years include increasing fidelity with computer-assisted planning, the use of patient-specific fixation, expanding indications for management of upper airway obstruction, and shifts in orthodontic-surgical paradigms. This review article serves to highlight the contemporary practice of orthognathic surgery.

Application of Surgery-First Approach in Treating Skeletal Dentofacial Asymmetry with Orthognathic Surgery

BACKGROUND

Skeletal dentofacial asymmetry decreases patient's attractiveness by deteriorating symmetry of facial appearance which is of great significance to individuals. Surgery-first orthognathic approach manifests its advantages of shortening treatment time and improving patient's quality of life. However, current literature on surgery-first approach mainly focuses on treating prognathism, overlooking its efficacy in improving facial symmetry of skeletal dentofacial asymmetry patients. This study aimed to assess SFA's efficacy in improving facial appearance by analyzing morphological features of asymmetric bone and facial soft tissue in a three-dimensional manner.

METHODS

Thirty-four patients who received orthognathic surgery in a surgery-first fashion were included. Based on three-dimensional CT reconstruction, bilateral preoperative morphological features and postoperative symmetry of hard tissue were compared respectively. Efficacy of facial soft tissue symmetry restoration was evaluated using root mean square deviation (RMSD).

RESULTS

Asymmetric features mainly located in menton, mandibular body length, angulation between ramus and midsagittal plane (MSP), distance between gonion and MSP and so on, which were significantly restored after the whole treatment. RMSD of facial soft tissue surface were significantly declined after the treatment and prognathism was corrected simultaneously if existed.

CONCLUSIONS

Surgery-first orthognathic approach is proved to be capable of treating skeletal dentofacial asymmetry effectively and efficiently.

Orthodontic Perspective for Face Asymmetry Correction

Facial symmetry affects the perception of facial beauty. Overall, facial harmony with an appropriate facial proportion and satisfactory midline facial symmetry are crucial factors for facial attractiveness. The role of orthodontists in correcting facial asymmetry begins with providing suitable diagnosis of the condition and identifying patients’ expectations. Through a thorough, subjective clinical evaluation of dentofacial asymmetry, the procedures for the surgical orthodontic management of facial asymmetry are discussed. The aim of this clinical review is to provide information on surgical indications for facial asymmetry, optimal treatment goals, presurgical orthodontic preparation, the surgery-first approach, three-dimensional (3D) surgical simulation, postsurgical orthodontic finishing, and treatment outcome evaluation. A comprehensive 3D diagnosis with appropriate planning, accurate transference of surgical simulation to real surgery, slight overcorrection, periodic assessment of treatment outcomes, and awareness of treatment limitations are essential to improve treatment outcomes of facial asymmetry.

An Overview of Maxillofacial Approaches to Smile Design

The oral and maxillofacial surgeon (OMS) has the knowledge and skills to make drastic skeletal changes in favor of a more cosmetic smile. OMS can alter intraoral and extraoral soft tissues to make subtle or significant changes in facial cosmesis. This article provides an overview of the scope of the OMS in smile design. The authors provide a cursory review of pertinent gross and surgical facial anatomy, discuss the role of orthognathic surgery and rhinoplasty in smile cosmesis, and describe the fundamentals of common cosmetic procedures ranging from gingivoplasty to lip lift and lip augmentation and the use of neurotoxins.

Skeletal stability after bimaxillary surgery with surgery-first approach for class III asymmetry is not related to virtual surgical occlusal contact

OBJECTIVES

Surgery-first orthognathic surgery is rarely used in class III asymmetry due to concerns of reduced skeletal stability from unstable surgical occlusion. This study aimed to evaluate if skeletal stability after surgery-first orthognathic surgery is related to virtual surgical occlusal contact or surgical change.

MATERIALS AND METHODS

We studied 58 adults with class III asymmetry, consecutively corrected by Le Fort I osteotomy and bilateral sagittal split osteotomy using a surgery-first approach. Dental casts were manually set to measure virtual surgical occlusal contact including contact distribution, contact number, and contact area. Cone-beam computed tomography taken before treatment, 1-week post-surgery, and after treatment was used to measure surgical change and post-surgical stability of the maxilla and mandible in translation (left/right, posterior/anterior, superior/inferior) and rotation (pitch, roll, yaw). The relationship between skeletal stability and surgical occlusal contact or surgical change was evaluated with correlation analysis.

RESULTS

Significant instability was found in the mandible but not in the maxilla. No correlation was found between the maxillary or mandibular stability and surgical occlusal contact (all p > 0.01). However, a significant correlation was found between the maxillary (roll and yaw) or mandibular (shift, roll and pitch) stability and its surgical change (all p < 0.001).

CONCLUSIONS

In correction of class III asymmetry with surgery-first bimaxillary surgery, the skeletal stability is not related to the virtual surgical occlusal contact, but surgical skeletal change.

CLINICAL RELEVANCE

Planned over-correction is a reasonable option for correction of severe shift or roll mandibular asymmetry in bimaxillary surgery for class III deformity.