Mandibular advancement surgery in high-angle and low-angle class II patients: different long-term skeletal responses

Hanna's Modified Sagittal Split Osteotomy (HSSO): An Alternative to Inverted L Osteotomy-Merging Function and Aesthetics for Enhanced Stability, Attractiveness, and Nerve Protection

Background: The current high standards in orthognathic surgery demand surgical solutions that are both ⁠ functionally ⁠ effective and aesthetically pleasing. Our approach offers one for enhanced stability, attractiveness, and nerve protection ⁠ with improved accessibility ⁠ in the majority of orthognathic scenarios ⁠ compared to an inverted L osteotomy. Methods: A case series is presented to illustrate the application and outcomes of HSSO, an optimised approach that combines the advantages of a transoral inverted L osteotomy with specific enhancements and increased versatility, ⁠ with accessibility and exposure similar to a BSSO. Results: HSSO as a completely transoral technique, demonstrate the ability to perform significant counterclockwise rotations of the mandible, eliminating the need for trocars or skin incisions. We experinced high postoperative stability when HSSO was performed in conjunction with a three-piece LeFort 1 osteotomy on a dynamic opposing arch. In comparison to an inverted L approach, we postulated that HSSO offers advantages in stability, due to the increased segmental overlap of the proximal and distal segments of the mandible. This approach is designed to enhance the safety of the inferior alveolar nerve compared to traditional sagittal split methods. Furthermore, HSSO represents an alternative to total joint replacement in select cases of idiopathic condylar resorption and is effective for correcting mandibular asymmetries while maintaining jawline aesthetics. This is achieved through the manipulation of the mandibular angle, ramus height, and inferior border without creating a step deformity in the soft tissue. Conclusions: The outcomes of HSSO highlight its capacity to deliver predictable, functional, and aesthetically pleasing results, offering a viable alternative to more traditional orthognathic techniques.

Assessment of temporomandibular joint disc position and skeletal stability after bimaxillary surgery

PURPOSE

This study aimed to assess the correlation between temporomandibular joint (TMJ) disc position and skeletal stability and identify the cephalometric measurements associated with relapse after bimaxillary surgery.

METHODS

The participants were 62 women with jaw deformities (124 joints) who underwent bimaxillary surgery. The TMJ disc position was classified into four types (anterior disc displacement (ADD), anterior, fully covered, and posterior) using magnetic resonance imaging, and cephalometric analysis was performed preoperatively and 1 week and 1 year postoperatively. The differences between pre- and 1-week postoperative values (T1) and 1-week and 1-year postoperative value (T2) were calculated for all cephalometric measurements. Moreover, the relationship between skeletal stability using cephalometric measurements, skeletal class, and TMJ disc position was analyzed.

RESULTS

The participants included 28 patients in class II and 34 in class III. There was a significant difference in T2 in SNB between class II mandibular advancement cases and class III mandibular setback cases (P = 0.0001). In T2, in ramus inclination, there was a significant difference between the ADD and posterior types (P = 0.0371). Stepwise regression analysis revealed that T2 was significantly correlated with T1 for all measurements. However, the TMJ classification was not applied to all measurements.

CONCLUSION

This study suggested that TMJ disc position, including ADD, could not affect skeletal stability, including the maxilla and distal segment after bimaxillary osteotomy, and short-term relapse could be related to the movement amount or angle change by surgery for all measurements.

Three-dimensional analysis of hard and soft tissue changes in skeletal class II patients with high mandibular plane angle undergoing surgery

This study aimed to study 3-dimensional (3D) changes of hard and soft tissues of skeletal class II patients after 2-jaw surgery and genioplasty. 32 adult patients diagnosed with mandibular hypoplasia who underwent 2-jaw surgery of maxillary impaction, mandibular advancement and genioplasty were enrolled. Cone-beam computed tomography and 3D stereophotogrammetry was conducted 1 week before and 6 months after surgery. Dolphin imaging software was used to establish a 3D digitizing model and 3D measurement system. Paired t-test was performed to compare the values before and after surgery. Pearson's correlation test assessed the degree of correlations between hard and soft tissue change. The mean impaction of the maxilla was 2.600 ± 3.088 mm at A. The mean advancement of the mandible was 7.806 ± 2.647 mm at B. There was a significant upward and forward movement for most landmarks of the nose and lip, while a significant decrease in nasal tip height (lateral view), upper lip height, and upper and lower vermilion height. The nose's width was significantly increased. For maxillary, Sn, Ac-r, Ac-l, and Ls demonstrated a significant correlation with A and U1 in the anteroposterior axis. However, there were no significant correlations among them in the vertical axis. For mandibular, Li demonstrated a significant correlation with L1 in the anteroposterior axis specifically for the mandible. Notably, correlations between the landmarks of the chin's hard and soft tissues were observed across all axes. The utilization of 3-D analysis facilitated a quantitative comprehension of both hard and soft tissues, thereby furnishing valuable insights for the strategic formulation of orthognathic treatment plans targeting patients with skeletal class II conditions.

Skeletal stability after mandible bilateral sagittal split osteotomy - comparison of patient-specific implant and mini-plate fixation: A retrospective study

The aim of the study was to compare the stability of the virtual surgical planning (VSP) and computer-aided design accompanied by patient-specific implants (PSIs) and conventional mini-plates in mandible advancement with bilateral sagittal split osteotomy (BSSO). This retrospective study evaluates the clinical and cephalometric records of 53 patients (12 male, 41 female) treated with BSSO in Helsinki University Hospital. Subjects were divided into two groups: VSP-PSI (21 patients: 4 male and 17 female; mean age 38 years, range 25-53 years); and conventional wafer-based repositioning with mini-plate fixation (32 patients: 8 male and 24 female; mean age 39 years, range 21-56 years). The effect of the amount and direction of the advancement on the stability was also analysed individually. The standardized lateral cephalometric radiographs in three time points were analysed to compare the groups. After surgery (T2), there were no differences between groups in cephalometric variables. During follow-up (T2-T3), the cephalometric variables in both Groups A and B were stable, so there was no difference in stability between the VSP-PSI and the conventional mini-plate groups. During follow-up, the mandibles rotated clockwise or counterclockwise, relapsed towards their original direction, and the changes were statistically significant (jaw relationship; p = 0.018, soft tissue profile; p = 0.025); when the advancement of mandible was >6 mm, the increase in gonial angle compared to mandibles advanced ≤6 mm was statistically significant (p = 0.03). VSP-PSI and conventional mini-plate fixation can be considered equally stable. Large advancements with counterclockwise rotation regardless of fixation method are more susceptible to relapse. VSP-PSI alone cannot solve the relapse-related concerns in mandible osteotomy.

Long-term Stability Over 2 Years After Isolated Maxillary Orthognathic Surgery Combined With Mandibular Autorotation in Risk Patients for Condylar Resorption

OBJECTIVE

Counterclockwise rotation of mandible can cause condylar resorption and condylar displacement posteroinferiorly after maxillary orthognathic surgery with mandibular in patients with high-angle mandibular retrognathism. This study was aimed to evaluate long-term stability >2 years and postoperative changes of condylar displacement.

MATERIALS AND METHODS

In 15 patients who underwent Le Fort I osteotomy with mandibular autorotation, postoperative stability was cephalometrically investigated until 2 years. Condylar changes were analyzed with transcranial temporomandibular joint projection. Correlation between condylar displacement and surgical movement was analyzed.

RESULTS

Significant clockwise relapse of mandible ( P <0.01 for SNB reduction and backward movement of point B) was observed between 6 months and >2 years after surgery, even though the values were small (0.5±0.1 degrees and 1.14±0.13 mm, respectively). The condyle was displaced posteroinferiorly immediately after surgery; however, it achieved a stable position at postoperative 6 weeks. The amount of vertical condylar displacement was significantly correlated with surgical change in mandibular posterior border sagittal angle, palatal plane angle, facial height ratio, and point B in the horizontal dimension. Greater mandibular rotation prompted more vertical condylar displacement.

CONCLUSIONS

Small mandibular relapse in long term should be considered after maxillary orthognathic surgery with mandibular autorotation, although it is regarded as a surgical maneuver to minimize mandibular instability in patients susceptible to postoperative condylar resorption.

Long-Term Follow-Up of Orthognathic Surgery in 19 Patients with Juvenile Idiopathic Arthritis

Objectives

Dentofacial deformity following juvenile idiopathic arthritis with temporomandibular joint involvement is associated with functional, aesthetic, and psychosocial impairment. Surgical treatment may involve combinations of orthognathic surgery. The aims of this retrospective study were to assess orofacial symptoms, functional and aesthetic status, and stability after orthognathic surgery.

Material and Methods

Nineteen patients with juvenile idiopathic arthritis of the temporomandibular joint (TMJ) and dentofacial deformities were included. All patients were treated with combinations of bilateral sagittal split osteotomy, Le Fort I and/or genioplasty, between September 10, 2007 and October 17, 2017. Analysis of patient symptoms and clinical registrations, and frontal/lateral cephalograms was performed pre- and postoperative and long-term (mean: 3.8 and 2.6 years, respectively).

Results

Patients experienced no changes in orofacial symptoms or TMJ function, and stable normalisation of horizontal and vertical incisal relations at long-term (horizontal overbite; vertical overbite: P < 0.05). Mandibular lengthening was achieved postoperatively (from mean 79.7 to 87.2 mm; P = 0.004) and was stable. Sella-nasion to A point (SNA) and sella-nasion to B point (SNB) angles increased postoperatively (SNA, mean 79.9° to 82.8°; P = 0.022 and SNB, mean 73.9° to 77.8°; P = 0.003), however, largely reverted to preoperative status at long-term.

Conclusions

Orthognathic surgery normalized incisal relations while providing stable mandibular lengthening without long-term deterioration of temporomandibular joint function or orofacial symptoms. No long-term effect on jaw advancements was observed.

Treatment of severe micrognathia in an adult with distraction osteogenesis: A case report

Key Clinical Message

Distraction osteogenesis (DO) of the mandible is often performed at a young age, and there are few reports after age 30, as in this case. The Hybrid MMF used in this case was useful in that it allowed correction of fine directionality.

Abstract

DO is often performed in young patients with a high capability of osteogenesis. We performed distraction surgery for a 35-year-old man who had severe micrognathia with serious sleep apnea syndrome. Four years postoperatively, suitable occlusion and improvement of apnea were observed.

Stability of vertical dimension following total arch intrusion

BACKGROUND

The purpose of this study is to evaluate stability of vertical dimension following total arch intrusion using miniscrews by measuring the change during treatment and relapse amount after more than one year of retention.

METHODS

Thirty patients (6 men, 24 women) were included in this study. Lateral cephalographs were taken with conventional radiography at the start of treatment (T0), after treatment (T1), and at least one year after treatment (T2). The evaluation was performed by measuring changes of selected parameters during treatment and the extent of relapse after more than one year.

RESULTS

During total arch intrusion treatment (T1-T0), anterior and posterior teeth intruded significantly. The mean vertical distance between the maxillary posterior teeth and palatal plane was reduced by 2.30 mm (P < 0.001). The mean vertical distance between the maxillary anterior teeth and palatal plane was reduced by 2.04 mm (P < 0.001). The anterior facial height was also reduced by 2.70 mm (P < 0.001). During retention period (T2-T1), the vertical distance between the maxillary anterior teeth and the palatal plane significantly increased by 0.92 mm (P < 0.001). The anterior facial height increased by 0.81 mm (P < 0.01).

CONCLUSIONS

Anterior facial height significantly decreases after treatment. During retention period, relapse of AFH and maxillary anterior teeth observed. There was no correlation between initial amount of AFH, mandibular plane angle, or SNPog and posttreatment AFH relapse. However, there was a significant correlation between the amount of intrusion of anterior and posterior teeth achieved by the treatment and the extent of relapse.

Treatment Strategy for Condyle/Ramus Deficiency Using 3D Virtual Surgery and CAD/CAM Technologies; Total Joint Replacement or Inverted-L Osteotomy

OBJECTIVE

To introduce a guideline for selecting proper surgical modalities for correction of skeletal Class II malocclusion with moderate-to-severe vertical height deficiency (VHD) of the condyle/ramus complex (CRC) using bimaxillary surgery in conjunction with total joint replacement (TJR) or inverted-L osteotomy (ILO) assisted by 3D virtual surgical planning and CAD/CAM technologies.

CASES

Four cases of severe skeletal Class II patients with moderate-to-severe VHD of CRC were presented. They underwent bimaxillary surgery using Le Fort I osteotomy in the maxilla and TJR or ILO in the mandible, with the help of virtual surgical planning (VSP) and computer-aided design/computer-aided manufacturing (CAD/CAM)-printed surgical guides and osteosynthesis plates. Guidelines are as follows: (1) if a patient has a moderate degree of VHD and the function of the temporomandibular joint (TMJ) is normal, ILO would be preferred for vertical elongation of the ramus; (2) if a patient has congenitally small condyle or severe condylar resorption, TJR would be preferred to resolve severe VHD of CRC; and (3) when a patient has a metal allergy, foreign body reaction or anatomic limitations (ie, thin cranial base cortex for fossa fixation), ILO would be a better option than TJR.

RESULTS

TJR or ILO using VSP and CAD/CAM-printed surgical guides, wafers, and customized plates can provide a proper selection of the surgical plan, accurate transfer of surgical plans to actual surgical procedures, and esthetic improvement of the facial profile.

CONCLUSION

This guideline based on the degree of VHD and functional aspects of CRC might help clinicians to select effective surgical modality for correction of skeletal Class II malocclusion with moderate-to-severe VHD of CRC.

Is Orthognathic Correction with TMJ Preservation A Stable Treatment Option for Patients with Juvenile Idiopathic Arthritis?

Purpose

The purpose of this study was to evaluate the long-term skeletal stability of orthognathic correction of dentofacial deformities secondary to juvenile idiopathic arthritis (JIA) in individuals without total alloplastic joint reconstruction.

Materials and Methods

The investigators designed and implemented a retrospective case series of patients diagnosed with JIA who underwent bimaxillary orthognathic surgery. To evaluate the long-term skeletal changes, the maxillary palatal plane to mandibular plane angle, anterior facial height, and posterior facial height measurements were evaluated through cephalograms.

Results

Six patients met inclusion criteria. All subjects were female (mean 16.2 years). Four patients demonstrated < 1° of change of the palatal plane to mandibular plane angle, and all patients had < 2° of change. Three patients had < 1% change in the anterior to posterior facial height ratio. Three patients demonstrated relative posterior facial shortening compared to anterior facial height (< 4%). No patients developed postoperative anterior open-bite malocclusion.

Conclusion

Orthognathic correction of the JIA DFD deformity with TMJ preservation is a viable modality to improve facial esthetics, occlusion, upper airway and speech swallowing and chewing mechanisms in select patients. The measured skeletal relapse did not affect the clinical outcome.

Retrospective study on the pharyngeal airspace in the lateral cephalogram - A mathematical model to predict changes due to bimaxillary orthognathic surgery

The aim of this study was the development of a statistical model for reliable prediction of Posterior Airway Space (PAS) changes in lateral cephalograms (LCR) of patients after bimaxillary orthognathic surgery. The LCRs of patients who underwent bimaxillary orthognathic surgery were retrospectively analyzed. The anteroposterior dimension of the PAS was measured at three levels in the pre-operative and postoperative LCR: On the nasopharyngeal (SPAS), oropharyngeal (MAS), and hypopharyngeal level (IAS). The data of 139 patients were collected. The following changes of the PAS were measured: in class II patients SPAS: 0.291 mm (SD = 2.570 mm); MAS: 2.444 mm (SD = 2.986 mm); IAS: 0.750 mm (SD = 3.017 mm); in class III patients SPAS: 1.377 mm (SD 3.212 mm); MAS: 0.962 (SD: = 3.135 mm); IAS: 0.370 mm (SD = 3.468 mm). Linear regression analysis showed for class II patients, a significant influence of mandibular movement on MAS (p = 0.049) and a significant effect of maxillary and mandibular movements on SPAS (p = 0.001) and MAS (p = 0.022) in class III patients. The other jaw displacements had no significant impact on the investigated PAS levels. While the presented method does not permit exact prediction of the dimension of the PAS, it is still an easily accessible method of orientation for the surgeon. The surgeon can initiate three-dimensional examinations to provide exact three-dimensional prediction based on this calculation.

Does maxillomandibular fixation affect skeletal stability following mandibular advancement? A single-blind clinical trial

BACKGROUND

The stability of the results remains a significant concern in orthognathic surgeries. This study aimed to assess the amount of relapse following mandibular advancement with/without maxillomandibular fixation (MMF).

MATERIALS AND METHODS

A single-blind clinical trial was conducted on patients with mandibular retrognathism who underwent BSSO for mandibular advancement and Lefort I maxillary superior repositioning. Patients were randomly divided into two groups of treatment (MMF) and control (no MMF). In the treatment group, MMF was performed for 2 weeks; meanwhile, MMF was not performed in the control group, and only guiding elastics were applied postoperatively. Lateral cephalograms were obtained preoperatively (T1), immediately after surgery (T2), and at 1 year postoperatively (T3). The distance from points A and B to the X and Y plane were measured to identify the amount of vertical and horizontal relapse in 1 year as a primary outcome. An independent t-test was applied in order to find differences in outcomes between the control and treatment groups.

RESULTS

Fifty-eight patients were evaluated in two groups (28 patients in the MMF group and 30 in the no-MMF group). The magnitude of mandibular advancement following BSSO was 7.68±1.39 mm and 7.53±1.28, respectively, without significant difference among the groups (p= 0.68). The mean sagittal and vertical changes (relapse) at point B were significantly different between the two groups at 1-year follow-up after the osteotomy (p=0.001 and p=0.05, respectively).

CONCLUSION

According to the results of this study, patients with short-term MMF following BSSO for mandibular advancement benefit from significantly greater skeletal stability in the sagittal and vertical dimensions.

Changes in the condylar volume and skeletal relapse following orthognathic surgery in patients with dentofacial deformity: A retrospective study

OBJECTIVE

To evaluate the relationship between the changes in condylar volume and maxillofacial skeletal morphology according to sex as well as the relationship between condylar volume reduction and skeletal relapse in patients who underwent orthognathic surgery.

METHODS

Ninety-five patients were categorized into skeletal Class III, Class II, and facial asymmetry groups. Computed tomography scans taken preoperatively and at 1 year postoperatively were used for quantitative measurement.

RESULTS

Postoperative condylar volume was reduced in both the Class II group and the deviated side of the asymmetry group. Both female and Class II deformity were significant predictors of postoperative reduction in the condylar volume. There was a significant correlation between skeletal relapse and postoperative change in condylar volume in the Class II group.

CONCLUSION

Postoperative condylar resorption may be associated with preoperative maxillofacial skeletal morphology and sex and also with skeletal relapse in the Class II group.

Short-Term Stability After Segmental Le Fort I Maxillary Impaction Surgery With Mandibular Autorotation in Seven High-Angle Class II Patients: A Case Series

PURPOSE

To retrospectively evaluate skeletal stability after Le Fort I maxillary impaction surgery and mandibular autorotation without bilateral sagittal split osteotomy (BSSO) in high-angle class II patients.

MATERIALS AND METHODS

Seven female high-angle class II patients who underwent maxillary impaction surgery and mandibular autorotation without bilateral sagittal split osteotomy were included in this study. Surgical changes and relapse were measured on lateral cephalograms taken preoperatively and at 1 month, 6 months and 1 year postoperatively.

RESULTS

The horizontal movement of the maxilla at point A was 5.8 ± 3.3 mm backward, and the upward movement at the posterior nasal spine was 3.3 ± 1.4 mm. The mean horizontal change at point A during the 1-year follow-up period was 0.1 ± 0.2 mm, and the vertical change at posterior nasal spine was 0.2 ± 1.3 mm, which were not statistically significant. The horizontal surgical change at point B was 4.0 ± 1.8 mm forward and the vertical surgical change at point B was 4.7 ± 1.8 mm upward. Postoperative relapse was 10.9% and 13.7% in the horizontal and vertical directions, respectively.

CONCLUSIONS

Le Fort I maxillary impaction surgery with mandibular autorotation may be 1 of the suitable procedures for high-angle class II patients.

Relapse and temporomandibular joint dysfunction (TMD) as postoperative complication in skeletal class III patients undergoing bimaxillary orthognathic surgery: A systematic review

Objectives

The aim of this study was to determine Relapse and TMD as postoperative complication in skeletal class III patients undergoing bimaxillary orthognathic surgery.

Materials and methods

Data was obtained by database searching using The Cochrane Central Register of Controlled Trials (central), PUBMED, SCOPUS, EMBASE, Google scholar, National Medical library, New Delhi. The titles and abstracts of the electronic search results were screened and evaluated by two observers for eligibility according to the inclusion and exclusion criteria.

Results

5261 articles were retrieved for the review. Among these, 3474 duplicate articles were removed. 418 studies were selected based on the eligibility criteria. For the present review, 30 articles were included after elimination according to the inclusion criteria. The Prisma diagram flowchart demonstrates our selection scheme. Quality assessment criteria to evaluate the studies were decided by two review authors in accordance with CONSORT guidelines. Each study was assessed using the evaluation method described in the Cochrane Handbook for Systematic Reviews. Among the 30 studies included in the review, marked degree of relapse in the mandible was noted from 3 months - 1 year postoperatively in 8 studies, 5 studies reported both TMD prevalence and relapse, whereas only 4 studies reported TMD disorder alone.

Conclusion

Complications of relapse and TMD are associated with bimaxillary orthognathic surgery procedures. More RCTs and CCTs are needed in this regard to get better quality evidence. This review was registered with PROSPERO: CRD42020211342.

Three-dimensional surgical guide approach to correcting skeletal Class II malocclusion with idiopathic condylar resorption

Treatment of skeletal Class II patients with dual bite and idiopathic condylar resorption (ICR) is challenging for orthodontists because of the unstable position of the mandible as well as skeletal relapse attributed to improper seating of the mandibular condyles. This case report describes the successful treatment of an 18-year-old Mongolian man diagnosed with centric relation-maximum intercuspation discrepancy and ICR. After making a definitive diagnosis from verified centric relation using bilateral manipulation, orthodontic treatment was initiated followed by three-dimensional computer-aided design/computer-aided manufacturing prebent titanium plate-guided sagittal split ramus osteotomy and genioplasty. Postoperative 3D superimposition demonstrated that this surgical guide approach provided accurate repositioning of the condyles, which were well positioned in the fossae. Complete orthodontic and surgical treatment time was 24 months. The patient's facial appearance and occlusion improved significantly, and a stable result was obtained with a 1-year follow-up.

The role of muscular traction in the occurrence of skeletal relapse after advancement bilateral sagittal split osteotomy (BSSO): A systematic review

The aim of this systematic review was (i) to determine the role of muscular traction in the occurrence of skeletal relapse after advancement BSSO and (ii) to investigate the effect of advancement BSSO on the perimandibular muscles. This systematic review reports in accordance with the recommendations proposed by the Preferred Reporting Items for Systematic Reviews and Meta‐Analyses (PRISMA) statement. Electronic database searches were performed in the databases MEDLINE, Embase and Cochrane Library. Inclusion criteria were as follows: assessment of relapse after advancement BSSO; assessment of morphological and functional change of the muscles after advancement BSSO; and clinical studies on human subjects. Exclusion criteria were as follows: surgery other than advancement BSSO; studies in which muscle activity/traction was not investigated; and case reports with a sample of five cases or fewer, review articles, meta‐analyses, letters, congress abstracts or commentaries. Of the initial 1006 unique articles, 11 studies were finally included. In four studies, an intervention involving the musculature was performed with subsequent assessment of skeletal relapse. The changes in the morphological and functional properties of the muscles after BSSO were studied in seven studies. The findings of this review demonstrate that the perimandibular musculature plays a role in skeletal relapse after advancement BSSO and may serve as a target for preventive strategies to reduce this complication. However, further research is necessary to (i) develop a better understanding of the role of each muscle group, (ii) to develop new therapeutic strategies and (iii) to define criteria that allow identification of patients at risk.

Comparison of bicortical, miniplate and hybrid fixation techniques in mandibular advancement and counterclockwise rotation: A finite element analysis study

OBJECTIVE

This study aims to evaluate biomechanical stability and stress distribution of five different fixation types with finite element analysis using 10-mm advancement with or without counterclockwise rotation of the mandible.

MATERIALS AND METHODS

After sagittal split osteotomy, 10-mm advancement was performed in the first group and 10-mm advancement and 10-degree counterclockwise rotation were performed in the second group. One miniplate (M-1), two-miniplate (M-2), one miniplate and a bicortical screw (H), l-shaped bicortical screw (B-1), and inverted l-shaped bicortical screw (B-2) systems were placed. Totally, 120 N force was applied to the models at a 45-degree angle from the lower edge of the symphysis.

RESULTS

The highest values on fixation were seen with miniplate, while the mean values were obtained with bicortical screw system. The highest values on bone were achieved using bicortical screws. One miniplate (M-1) showed both the highest and mean displacement. The highest values in counterclockwise-rotated models increased in all parameters, compared to non-rotated models.

CONCLUSION

In cases in which passive alignment between segments and adequate bone contact are ensured, inverted l-shaped bicortical screw, two-miniplate, or hybrid systems are recommended.

Patient satisfaction after orthognathic surgery: a 3 year follow-up of 60 high-angle Class II individuals

BACKGROUND AND OBJECTIVES

High-angle Class II malocclusion is considered challenging to treat to a stable result and, although studies report treatment outcome in terms of morphology, patient satisfaction has not been addressed. The objectives of the present study were to examine patients' motives for treatment and satisfaction with the results.

MATERIAL AND METHODS

A structured questionnaire was distributed 3 years post-operatively to 93 consecutively treated patients with an initial diagnosis of mandibular-plane angle (ML/NSL) ≥34.0 degrees and ANB angle ≥4.0 degrees. Three surgical subsamples were defined: one-piece Le Fort I, bilateral sagittal split osteotomy, or a combination of the two (Bimax). Lateral cephalometric radiographs were used to assess morphological characteristics and post-treatment changes.

RESULTS

Questionnaire participation was 69.8 per cent. The most frequently reported motives for seeking treatment were to improve oral function (85.0 per cent) and dental appearance (71.7 per cent). Thirty per cent were very satisfied, 53.3 per cent were satisfied, and 16.7 per cent were dissatisfied with the overall treatment result. Dissatisfaction was associated with a persisting post-treatment anterior open bite (AOB), horizontal relapse at B point, and with sensory impairment.

CONCLUSIONS AND IMPLICATIONS

A higher rate of dissatisfaction was found than what has usually been reported for othognathic surgical patients, and this was associated with a persisting AOB. In addition, mandibular relapse and impaired sensory function were related to dissatisfaction and are associated with mandibular surgery. Prospective high-angle Class II patients should be comprehensively informed about the unpredictability of treatment outcomes in terms of occlusion and facial appearance.

Long-term stability and condylar remodeling after mandibular advancement: A 5-year follow-up

INTRODUCTION

This study evaluated whether presurgical characteristics, the magnitude of mandibular advancement, and changes in mandibular plane angle are correlated with long-term stability and postsurgical condylar remodeling and adaptations using 3-dimensional imaging.

METHODS

Forty-two patients underwent bilateral sagittal split osteotomies for mandibular advancement using rigid fixation. Cone-beam computed tomography (CBCT) scans were acquired before surgery (T1), immediately after surgery (T2), and at long-term follow-up (T3). The average follow-up period was 5.3 ± 1.7 years after surgery. Anatomic landmark identification on the cone-beam computed tomographies and subsequent quantification of the changes from T1 to T2 and T2 to T3 were performed in ITK-SNAP (version 2.4; itksnap.org) and 3DSlicer (version 4.7; http://www.slicer.org) software. Surgical displacements, mandibular plane angle changes, and skeletal stability were measured relative to cranial base superimposition, whereas condylar remodeling was measured relative to regional condylar registration. Partial correlation coefficients were used to assess relationships between clinical and surgical variables, condylar remodeling, and long-term surgical relapse while controlling for variability in the length of follow-up.

RESULTS

B-point relapsed more than 2 mm posteriorly in 55% of the patients. The only variables strongly associated with the posterior movement of B-point long-term were mesial yaw of the condyle during surgery (P ≤0.01) and the length of follow-up from T2 to T3 (P ≤ 0.01). There was no relationship between the magnitude of advancement or presurgical mandibular plane angle and relapse or condylar resorption. Condylar resorption was strongly associated with relapse of B-point in the posterior direction (P ≤0.01) and clockwise rotation of the mandibular plane long-term (P ≤0.01). Twenty-nine percent of subjects showed resorption of more than 2 mm in the inferior direction at the lateral pole, and 17% of the subjects showed resorption of more than 2 mm in the inferior direction at condylion. Compared with male subjects, females exhibited significantly greater condylar remodeling (P ≤0.01) and slightly greater relapse at B-point (P ≤0.05).

CONCLUSIONS

Surgical relapse at B-point may occur slowly over time and is primarily due to condylar resorption in mandibular advancement patients. Mesial yaw of the condyle during surgery may lead to condylar resorption postsurgically. In addition, females are at greater risk of condylar resorption postsurgically.

One-year stability of the mandibular advancement and counterclockwise rotation for correction of the skeletal class II malocclusion and high mandibular plane angle: Dental and skeletal aspect

Background

The purpose of this study was to evaluate the stability on dental and skeletal aspect after surgical advancement and counterclockwise rotation for the correction of the mandibular deficiency in patients with high mandibular plane angle (MPA).

Methods

We analyzed the records of patients who had undergone surgical treatment for dentofacial deformities with mandibular deficiency and high MPA. Clinical and radiological data were taken 1 month before surgery (T0), 6 weeks after surgery (T1) and 1 year after surgery (T2). Cephalometric values of the MPA were recorded and compared. The cephalometric changes in the different time periods were defined as follows: A: postsurgical changes (T0–T1), B: one-year changes (T1–T2), and C: short term changes (T0–T2).

Results

Twenty-seven patients had prominent mandibular deficiency with an MPA of over 35° (high angle). The mean age of patients at surgery was 29.7 years. Seven patients had a single jaw procedure, 20 patients had bilateral sagittal split osteotomy (BSSO) combined with a Le Fort I osteotomy, and 14 patients had additional genioplasty. MPA values differed significantly between the time periods (p < 0.05) with an observed relapse of the angle. However, satisfactory clinical improvement was achieved in the dental and skeletal presentation. The overjet improvement was evident from 8.815 ± 2.085 mm (T0) to 3.426 ± 1.253 mm (T2).

Conclusion

Counterclockwise surgical advancement of the mandible to correct mandibular deficiency in patients with a high mandibular plane angle showed an overall acceptable stability during one-year follow-up.

Dynamic orthognathic surgical procedure (DOSP) in asymmetric maxillomandibular dysmorphism secondary to unilateral micrognathia: Outcomes of 12 consecutive cases

This study aimed to evaluate the outcomes following a dynamic orthognathic surgical procedure performed at the end of growth to treat asymmetric maxillomandibular deformities linked to unilateral micrognathia when conventional orthognathic surgery was not feasible. The dynamic orthognathic surgical procedure (DOSP) combined concomitant mandibular distraction osteogenesis with contralateral poorly stabilized sagittal split osteotomy and Le Fort I osteotomy. Cephalometric studies were retrospectively conducted on pre- and postoperative lateral and frontal cephalographs, and maxillomandibular movements were calculated. Outcome scores were computed by both experts and laypersons based on photographic analyses. There was a significant postoperative increase in height of the micrognathic ramus in all patients (n = 12; p = 0.002). The angle between the occlusal cant and horizontal reference plane decreased significantly in all of the patients, as did the angle between the midline sagittal plane and mandibular tilt (p < 0.001). Postoperative outcome scores showed significant improvements in all cases, according to both expert and layperson groups. This procedure allows correction of maxillomandibular asymmetries linked to micrognathia. However, it cannot resolve all the factors participating in facial asymmetry, such as those originating in the oculo-auriculo-ventricular spectrum or complex tumor sequelae, and second-step procedures may be required.

Biomechanical evaluation of a novel mandibular distraction osteogenesis protocol: an in-vitro validation and the practical use of the method

The aim of this study was to optimize and experimentally validate the certain parameters affecting the operation success of Mandibular Distraction Osteogenesis (MDO). According to FEA results, the displacement of the samples showed 28.5% reduction as only the osteotomy line was separately optimized, and 64.2% less displacement was determined when the osteotomy line and the screw configuration were optimized together. In consistent with the FEA results, the samples showed 62% and 84.5% fewer displacement values, respectively. As a result, the MDO protocol suggested, which is validated by both numerical and experimental studies, offers promising outcomes for operation success.

Distraction Osteogenesis Versus Orthognathic Surgery: Demystifying Differences in Concepts, Techniques and Outcomes

Introduction

The popularity and interest evoked by orthognathic surgery and distraction osteogenesis are undisputed in the field of oral and maxillofacial surgery. However, questions regarding the individual identities of either of them with clarity in their concepts, techniques and outcomes have remained unanswered. The aim of this review is to shed light on these questions.

Methods

This review is structured as a narrative review of thirty years of literature available in the specialities of orthognathic surgery and distraction osteogenesis.

Conclusion

The authors present a review of existing literature combined with contrasting experience gained over the years in providing an overview of the merits and demerits of the two surgical techniques which will aid the clinician in justifying the use of one technique over the other.

The three-dimensional evaluation of positional change in mandibular condyle after intraoral vertical ramus osteotomy

OBJECTIVES

The purpose of this study was to compare the changes of the condylar axis, the anteroposterior condylar position relative to the glenoid fossa, after intraoral vertical ramus osteotomy (IVRO).

STUDY DESIGN

21 patients diagnosed as skeletal class III malocclusion underwent IVRO and were followed according to the authors' postoperative management regimen. The three-dimensional positions of the condyles were evaluated by cone-beam computerized tomography (CBCT) at pre-op, post-op, and at follow-up. CBCT images were referenced to assess the condylar axis change and the anteroposterior condylar position in the glenoid fossa. A repeated-measures analysis of variance (P<0.05) also was performed.

RESULTS

After surgery, both the axial condylar angles and the anteroposterior condylar position were significantly different (P<0.05). The coronal condylar axis rotated outwardly. The anteroposterior condylar position in the glenoid fossa had moved from the concentric to the anterior position. But the condyle changes between post-op and follow-up (P>0.05) were insignificant.

CONCLUSIONS

With postoperative intermaxillary elastic traction, the condyles changed their positions physiologically for newly established jaw movement after IVRO.

Bimaxillary surgery to correct high-angle class II malocclusion: does a simultaneous genioplasty affect long-term stability?

BACKGROUND AND OBJECTIVES

High-angle skeletal Class II malocclusion is one of the most challenging dentofacial deviations to treat and, in adults, a combination of orthodontic treatment and bimaxillary orthognathic surgery is often indicated. This study examines the rate of clinically significant relapse and whether a genioplasty affects the treatment outcome of high-angle Class II malocclusions.

MATERIAL AND METHODS

Cephalometric tracings of 36 consecutively treated high-angle Class II patients were evaluated from pre-surgery to 3 years post-surgery. All patients had undergone bimaxillary surgery (Le Fort I and BSSO), 13 of them had in addition a genioplasty.

RESULTS

The maxilla remained stable, whereas relapse (greater than or equal to 2 mm) of the mandibular advancement was seen in 40 per cent of the patients. Advancement greater than 10 mm increased the risk for horizontal relapse. The overjet was normalized and remained stable despite mandibular relapse. Half of the patients had an anterior open bite 3 years post-surgery. A supplemental genioplasty did not affect the relapse rate.

CONCLUSIONS AND IMPLICATIONS

Overjet was normalized and remained stable long term; there was an open bite in half of the patients. Combined orthodontic and bimaxillary surgical treatment of high-angle Class II patients showed skeletal relapse (greater than or equal to 2 mm) of the mandible in 40 per cent of patients. Mandibular advancement greater than 10 mm increased the risk for relapse. There was no increased risk for dental or skeletal instability associated with a genioplasty in combination with maxillary and mandibular surgery in the treatment of high-angle skeletal Class II malocclusion.

Comparison of Changes in the Condylar Volume and Morphology in Skeletal Class III Deformities Undergoing Orthognathic Surgery Using a Customized versus Conventional Miniplate: A Retrospective Analysis

With the great leap in the development of three-dimensional computer-assisted surgical technology, surgeons can use a variety of assistive methods to achieve better results and evaluate surgical outcomes in detail. This retrospective study aimed to evaluate the postoperative stability after bilateral sagittal split ramus osteotomy by volume rendering methods and to evaluate how postoperative stability differs depending on the type of surgical plate. Of the patients who underwent BSSRO, ten patients in each group (non-customized miniplate and customized miniplate) who met the inclusion criteria were selected. Preoperative and postoperative cone-beam computed tomography data were collected, and condylar morphological and landmark measurements were obtained using Checkpoint and OnDemand software, respectively. The postoperative condylar morphological dataset revealed no significant difference (p > 0.05) between the two groups. No significant difference (p > 0.05) was observed between the two groups in horizontal, vertical, or angular landmark measurements used to quantify operational stability. These results indicate that there is no difference in the surgical outcome between the patient-specific system and the conventional method, which will allow clinicians to take advantage of the patient-specific system for this surgical procedure, with favorable results, as with the conventional method.

Do Patients With Different Mandibular Plane Angles Have Different Time to Relapse After Bilateral Sagittal Osteotomy With Mandibular Advancement?

PURPOSE

This study sought to answer the following question: Do patients with different mandibular plane angles (MPAs) have a different time to relapse after mandibular advancement with bilateral sagittal split osteotomy?

MATERIALS AND METHODS

We performed a retrospective cohort study of patients who underwent bilateral sagittal split osteotomy advancement at Massachusetts General Hospital between 2005 and 2017. The primary predictor variable was MPA, categorized as low (<25°), medium (between 25° and 35°), or high (>35°). The outcome variable was time to relapse (≥2-mm posterior change at the B point). Other covariates included gender, age, temporomandibular joint symptoms, bimaxillary surgery, direction of mandibular rotation, magnitude of advancement, genioplasty, and fixation method. Time to relapse was estimated using the Kaplan-Meier method. Cox and parametric regressions for interval-censored data were performed. P < .05 was considered statistically significant.

RESULTS

The sample was composed of 58 patients (40 female patients), with a mean age of 26.1 ± 4.9 years, grouped as follows: low MPA, n = 15; medium MPA, n = 26; and high MPA, n = 17. Clinically significant relapse was found in 18 patients (31%). Age, temporomandibular joint symptoms, counterclockwise rotation, and magnitude of advancement were statistically significantly different among the 3 groups. When we assessed time to relapse, the Kaplan-Meier method showed that high-MPA patients had a longer mean time at risk and higher estimated probabilities of relapse at different time points compared with low- and medium-MPA patients (P < .05). However, this association was not significant in Cox and parametric regressions.

CONCLUSIONS

Our results suggest that clinically significant relapse was found during the first postoperative year in low-MPA patients and from 2 to 5 years postoperatively in high-MPA patients. Multivariate regression analyses did not show a significant association between MPA and time to relapse, suggesting that other covariates may play a role in the observed time to relapse.

Independent risk factors for long-term skeletal relapse after mandibular advancement with bilateral sagittal split osteotomy

The purpose of this retrospective cohort study was to identify the independent risk factors for long-term skeletal relapse following mandibular advancement with bilateral sagittal split osteotomy. Univariate and multivariate linear regression analyses were performed including nine common risk factors for relapse as independent variables and horizontal/vertical long-term (≥2 years) skeletal relapse as dependent variables. Ninety-six patients were analyzed; 66 were female (68.8%) and the average age of the patients was 29.7±10.5 years. Over an average follow-up of 3.8±1.8 years after an initial mandibular advancement of 8.8±2.4 mm, long-term skeletal relapse of 1.6±1.0 mm horizontal and 0.9±0.7 mm vertical was found. Multivariate analysis identified age, preoperative mandibular plane angle (MPA), bimaxillary surgery, counterclockwise mandibular rotation, and the magnitude of mandibular advancement to be significantly associated with horizontal long-term skeletal relapse. Preoperative MPA, counterclockwise mandibular rotation, and the magnitude of mandibular advancement were significantly associated with vertical long-term skeletal relapse. Thus preoperative MPA, the magnitude of mandibular advancement, and counterclockwise mandibular rotation of the mandible were found to be independent risk factors for both horizontal and vertical long-term skeletal relapse. Although long-term skeletal relapse cannot be avoided entirely, understanding the independent risk factors and their contributions will optimize treatment planning and long-term stability.

Temporomandibular disorders in Class II malocclusion patients after surgical mandibular advancement treatment as compared to non-treated patients

BACKGROUND

Severe malocclusions may cause functional and aesthetic problems and symptoms of temporomandibular disorders (TMD). Studies have investigated association between malocclusions and TMDs and shown controversial findings.

OBJECTIVE

Purpose of this investigation was to examine the prevalence of TMD sub-diagnoses, using Diagnostic Criteria for the TMD (DC/TMD), in patients with Class II malocclusion and retrognathic mandible who had undergone mandibular advancement surgery 4-8 years previously, and to compare their frequencies with non-treated patients with a similar pre-existing condition.

METHODS

Study cohort comprised 151 patients who had orthognathic treatment due to mandibular retrognathia in 2007-2011. Seventy-seven (51%) participated in the study (Group 1). Group 2 comprised 22 patients who were planned for orthognathic treatment but had not started their treatment. Patients filled in the Finnish version of the DC/TMD Symptom Questionnaire and were examined using to the DC/TMD Axis I. DC/TMD Symptom Questionnaire were inquired by phone from 24 of the 74 patients who did not participate in the study.

RESULTS

Results showed that Group 2 had more myalgia (13% vs 50%, P < 0.001) and arthralgia (18% vs 65%, P < 0.001) sub-diagnoses than Group 1. A tendency was noted that Group 2 had more pain-related TMD symptoms than Group 1. No differences were found between Groups 1 and 3 in gender and age distribution or frequency TMD symptoms.

CONCLUSION

Prevalence of especially pain-related TMD diagnoses was higher in Group 2 compared to Group 1, thus indicating a possible beneficial effect of this treatment for TMD.

One-year postoperative skeletal stability of 3D planned bimaxillary osteotomies: maxilla-first versus mandible-first surgery

Orthognathic surgery is carried out to correct jaw deformities and to improve facial aesthetics. However, controversy surrounds whether the maxilla- or mandible-first surgery approach leads to better surgical outcomes. In our previous study, we have shown that in most instances, the maxilla-first surgical approach yielded closer concordance with the 3D virtual treatment plan than a mandibular-first procedure. However, the post-operative stability of each approach has not been investigated. Therefore, this one-year follow-up study was set-up and investigated the postoperative skeletal stability of the 3D planned translations and rotations after either the maxilla- or mandible-first surgery. In total, 106 patients who underwent bimaxillary surgery and had an individualized 3D virtual operation plans, received either maxilla-first (n = 53) or mandible-first (n = 53) surgery. 3D printed interocclusal splints were used during surgery to position the jaws. One year postoperatively a cone-beam computed tomography (CBCT) scan was made to assess the effects using the OrthoGnathicAnalyser. The mean sagittal, vertical and transverse relapse was less than 1.8 mm and no significant differences were found in relapse between the maxilla-first or the mandibular-first surgical procedure. Overall, this study shows that 3D virtual planning in combination with an optimised sequencing of osteotomies provides predictable long-term results in bimaxillary surgery.

Surgical correction of dentofacial deformities in juvenile idiopathic arthritis: a systematic literature review

The aim of this study was to assess current evidence for the surgical correction of dentofacial deformities in patients with temporomandibular joint (TMJ) involvement from juvenile idiopathic arthritis (JIA). A systematic literature review, according to the PRISMA guidelines, was conducted. Meta-analyses, randomized controlled trials, cohort studies, observational studies, and case reports were eligible for inclusion. Exclusion criteria were no JIA diagnosis, no clearly defined outcomes, dual publications (except meta-analyses), non peer-reviewed studies, non English language publications, and animal studies. The outcome measures assessed were TMJ function, skeletal alignment, and morbidity. The database search identified 255 citations, of which 28 met the eligibility criteria. Of these, 24 were case reports or case series with a low level of evidence that did not allow for meta-analysis. Extrapolated evidence supports orthognathic surgery in skeletally mature patients with controlled or quiescent JIA and a stable dentofacial deformity. Distraction osteogenesis was recommended for severe deformities. Some authors demonstrated unpredictable postoperative mandibular growth with costochondral grafts. Alloplastic TMJ reconstruction was efficacious, but should be used cautiously in skeletally immature patients. TMJ function and skeletal alignment was improved with reconstruction by any technique and morbidity was low. The surgical correction of arthritis-induced dentofacial deformities is indicated but the level of evidence is low. Prospective multicenter studies are needed.

Short-term hard and soft tissue changes after mandibular advancement surgery in Class II patients: a retrospective cephalometric study

Aim

The aim of this study was to describe hard and soft tissue changes after mandibular advancement surgery and to investigate the possible differences between Class II facial patterns.

Materials and methods

Lateral cephalograms of 109 patients who underwent combined orthodontic treatment and bilateral sagittal split osteotomy (BSSO) were studied. Radiographs were taken within 6 weeks before surgery (T0) and at least 6 months postoperatively (T1). Patients were classified into 3 groups according to the preoperative mandibular plane angle. Hard- and soft-tissue changes were analysed with an x-y cranial base coordinate system. Measurements were evaluated statistically.

Results

Soft and hard tissues of the chin moved forward and downward. The position of the upper lip remained unchanged, while the lower lip moved forward and upward and decreased in thickness. The soft tissue points of the chin follow their corresponding skeletal points almost completely, while the change of the lower lip was only 76 per cent of the movement of the underlying hard tissue. The increase of SNB was more evident in the low-angle group, as well as improvement of the facial convexity. Stomium superius moved more forward in the low- and medium-angle cases. Ratios of hard and soft tissue changes showed no differences for different facial patterns.

Limitations

Limitations derived from the retrospective study design. Only short-term changes could be addressed. The distinction between surgical changes and changes due to skeletal relapse is difficult to assess. Also, the difficulty to reproduce a relaxed lip position during imaging may influence our results.

Conclusion

Class II characteristics improved after mandibular advancement. Soft tissues of the chin follow their skeletal structures almost in a 1:1 relationship, while movement of the lower lip was less predictable. The facial pattern of Class II patients should be considered in treatment planning.

Three-dimensional quantitative assessment of surgical stability and condylar displacement changes after counterclockwise maxillomandibular advancement surgery: Effect of simultaneous articular disc repositioning

INTRODUCTION

In this study, we quantitatively assessed 3-dimensional condylar displacement during counterclockwise maxillomandibular advancement surgery (CMMA) with or without articular disc repositioning, focusing on surgical stability in the follow-up period.

METHODS

The 79 patients treated with CMMA had cone-beam computed tomography scans taken before surgery, immediately after surgery, and, on average, 15 months postsurgery. We divided the 142 condyles into 3 groups: group 1 (n = 105), condyles of patients diagnosed with symptomatic presurgical temporomandibular joint articular disc displacement who had articular disc repositioning concomitantly with CMMA; group 2 (n = 23), condyles of patients with clinical verification of presurgical articular disc displacement who had only CMMA; and group 3 (n = 14), condyles of patients with healthy temporomandibular joints who had CMMA. Presurgical and postsurgical 3-dimensional models were superimposed using voxel-based registration on the cranial base. Three-dimensional cephalometrics and shape correspondence were applied to assess surgical and postsurgical displacement changes.

RESULTS

Immediately after surgery, the condyles moved mostly backward and medially and experienced lateral yaw, medial roll, and upward pitch in the 3 groups. Condyles in group 1 showed downward displacement, whereas the condyles moved upward in groups 2 and 3 (P ≤0.001). Although condylar displacement changes occurred in the 3 groups, the overall surgical procedure appeared to be fairly stable, particularly for groups 1 and 3. Group 2 had the greatest amount of relapse (P ≤0.05).

CONCLUSIONS

CMMA has been shown to be a stable procedure for patients with healthy temporomandibular joints and for those who had simultaneous articular disc repositioning surgery.

Study of the mechanical reliability of an S-shaped adjustable osteosynthesis plate for bilateral sagittal split osteotomies. Study on 15 consecutive cases

INTRODUCTION

The main challenge during the osteosynthesis of a bilateral sagittal split osteotomy (BSSO) is to take into account the correct position of the condyle. Adjustable plates can be used to fine-tune the final occlusion without changing the osteosynthesis. A new type of adjustable plate is presented in this article. The aim is to assess the mechanical reliability of this system during the surgery and during the healing period, thanks to a preliminary prospective on 15 consecutive cases.

MATERIAL AND METHODS

The bridge of the plate studied here has an "S"-shape and can be bent in two different planes. Fifteen patients presenting a maxilla-mandibular disharmony have been operated on with this device. Clinical results were evaluated three months postoperatively and the mechanical reliability of the device was studied prospectively from teleradiographies of 15 patients operated on in our department.

RESULTS

This study shows good results, with respect to the mechanical reliability of this S-shaped adjustable plate, three months postoperatively corresponding to the bone-healing period. Radiographic observations did not show any significant displacement at the osteosynthesis site.

DISCUSSION

This preliminary study shows the mechanical reliability of this new S-shaped adjustable plate. Its semi-rigid character may allow for certain condyle position adaptability. No plate fracture was reported for this 15 patient series. These encouraging results have to be confirmed on a larger series.