The changes of oral health-related quality of life and satisfaction after surgery-first orthognathic approach: a longitudinal prospective study

BACKGROUND

To our best knowledge, there was little research to assess the changes of quality of life and satisfaction after orthognathic in one trial. The aim of this study was to evaluate the changes of oral health related quality of life and satisfaction between surgery-first and orthodontic-first orthognathic surgery.

METHODS

Fifty Chinese orthognathic adluts patients completed two questionnaires: the Dental Impact on Daily Living questionnaire for assessment of his/her satisfaction and 14-item Oral Health Impact Profile for assessment of patient's quality of life. The subjects completed six sets of interviews and clinical evaluations at before treatment; 1 month after surgery (surgery-first); 6 months after treatment; 12 months after treatment ; and 18 month after treatment ; the finished treatment. The pre and post surgical orthodontic period was also recorded. Chi square tests and repeated-measures analysis of variance (ANOVA) were used to compare categorical variables and measure results. All analyses were carried out used Stata software.

RESULTS

The quality of life was significant improved when finished treatment and the amounts of change did not show any significant difference in each domain and at 1, 6, 12 month after orthognathic surgery between two groups. However, in orthodontic-first group, the quality of life was deteriorated before orthognathic surgery. In surgery-first group, the quality of life was immediately improved which lead to better satisfaction.

CONCLUSIONS

Although the quality of life scores was no significant difference between two groups, surgery-first treatment could significant reduce treatment during and no deterioration stage of quality of life score which lead to better satisfactory compare to orthodontic-first group. However, some of limitations we need take caution. In future we still need conduct more study to assess the influence of surgery-first method on quality of life.

Operative time, blood loss, hemoglobin drop, blood transfusion, and hospital stay in orthognathic surgery

PURPOSE

This study was conducted to evaluate the operative time, blood loss, hemoglobin drop, blood transfusion, and length of hospital stay in orthognathic surgery.

METHODS

A 10-year retrospective analysis was performed on patients who underwent bilateral sagittal split osteotomy (with or without genioplasty), Le Fort I osteotomy (with or without genioplasty), or any combination of these procedures. A total of 271 patients were included.

RESULTS

The age range was 17 to 49 years, with a mean age of 24.13 ± 4.51 years. Approximately 62% of patients underwent double-jaw surgery. The most common procedure was bilateral sagittal split with Le Fort I (37%). The average operative time was 3.96 ± 1.25 h. The mean estimated blood loss was 345.2 ± 149.74 mL. Approximately 9% of patients received intraoperative blood transfusion. The mean hemoglobin drop in the non-transfusion cases was 2.38 ± 0.89 g/dL. The mean postoperative hospital stay was 1.85 ± 0.83 days. Only one patient was admitted to the ICU for one night.

CONCLUSIONS

In orthognathic surgery, blood loss is relatively minor, blood transfusion is frequent, and ICU admission is unlikely. Operative time, blood loss, blood transfusion, and the complexity of the surgical procedure can significantly increase the length of hospital stay. Males may bleed more than females in orthognathic surgery. Hemoglobin drop can be overestimated due to hemodilution in orthognathic surgery, which may influence the decision to use blood transfusion.

Evaluation of the mandibular split patterns in sagittal split ramus osteotomy

PURPOSE

To evaluate the split patterns of the mandibular ramus in sagittal split ramus osteotomy (SSRO) using cone-beam computed tomography (CBCT) and examine the related anatomic features that may be associated with these split patterns.

PATIENTS AND METHODS

The authors designed and implemented a retrospective cohort study and enrolled a sample composed of consecutive patients with different maxillofacial deformities who underwent an SSRO from July 2011 through October 2012 at the Department of Orthognathic Surgery at the Tianjin Stomatological Hospital of Nankai University. The split patterns, which were selected at random at 1 side per patient, were evaluated by CBCT as the outcome variable 1 month after the operation. The predictor variable was composed of a set of heterogeneous anatomic variables that could be associated with the split patterns. Type I split was defined as a split at the lingual side near the mylohyoid sulcus. Type II split was defined as a split at the posterior border of the mandibular ramus. Appropriate bivariate and regression statistics were computed, and the level of statistical significance was set at a P value less than .05.

RESULTS

One hundred thirty patients with different maxillofacial deformities (62 male and 68 female; mean age, 23 yr) underwent an SSRO. Two types of split patterns of the mandibular ramus were observed in SSRO: a split at the lingual side near the mylohyoid sulcus, which occurred in 75.38% of patients, and split at the posterior border region of the mandibular ramus, which occurred in 24.62% of patients. No fracture lines were observed through the mandibular canal. The thickness of the lingual cortical bone between the mandibular canal and the posterior border of the ramus was significantly associated with the split patterns (P < .05). The thickness of the cortical bone in the posterior border of the ramus, the degree of the mandibular angle, and the shapes of the mandibular ramus in the axial plane also were found to influence these split patterns. There was no meaningful association between the split patterns and a patient's age and gender.

CONCLUSION

The split patterns of the mandibular ramus during SSRO were influenced by some anatomic features of the mandibular ramus. Therefore, examining the anatomy of the mandible with CBCT before surgery may play an important role in predicting the split patterns of the mandibular ramus during SSRO.

Changes in natural head position in response to mandibular advancement

We investigated the change in the natural head position and its relation to the change in the mandibular position in patients with mandibular hypoplasia. Forty-one patients treated by orthognathic surgery were divided into three groups: bilateral sagittal split osteotomy (BSSO) advancement (n=8); BSSO advancement with genioplasty (n=12), and Le Fort I osteotomy with BSSO advancement (n=21). Cone-beam computed tomographic (CT) datasets were collected preoperatively and six weeks postoperatively. The natural head position was measured using the craniocervical angle and the distance from the second vertebra to the frontal plane, and the mandibular position was measured using the craniomandibular angle and the distance from the mandible to the frontal plane. Repeated measures two way ANOVA was used to assess the significance of differences between the angular and linear measurements, and Pearson's correlation coefficient to assess those between the change in the mandibular position and the natural head position. The craniomandibular angle increased and the mandible to frontal plane distance decreased, as planned; the craniocervical angle increased, and the distance from the second vertebra to the frontal plane decreased in all three groups. ANOVA showed a significant difference in the time factor (preoperative compared with postoperative) but no significant differences between the groups or interaction (time multiplied by group) factors. There was a significant correlation between the change in mandibular position and the change in the natural head position. Changes in the natural head position after correction of mandibular hypoplasia are correlated with the change in the mandibular position, regardless of whether a genioplasty or Le Fort I osteotomy was done.

Operative time, length of stay and reoperation rates for orthognathic surgery

Orthognathic surgery improves quality of life in terms of oral function and facial aesthetics. Our aim was to establish and compare operative time and length of inpatient stay for orthognathic procedures, and to assess the reoperation rate. Departmental electronic data base was used to identify all patients undergoing orthognathic surgery in a single unit between the 01/01/2016 and the 01/08/2018. 251 patients were identified who underwent 409 orthognathic surgery procedures. The mean operating time for a bimaxillary osteotomy (n=107) was 139.3 min. For single jaw procedures, the mean operating time for a Le Fort I osteotomy (n= 42) was 82.2 min and for a bilateral sagittal split osteotomy (BSSO) (n= 102) was 80.3min. Bimaxillary osteotomy combined with genioplasty (n=17) this increased the operating time on average by 31 min. and of a BSSO combined with a genioplasty (n=14) by 27 mins. The mean postoperative hospital stay was 1.2 ± 0.2 days. 96.4% patients spent only one postoperative night in hospital. 6/251 (2.4%) patients required re-operation. In regression analysis, age was the only significant factor in increasing length of stay (p<0.008), 95% CI 0.03-0.2). Our review shows short operating times and postoperative inpatient stays in a large cohort of patients undergoing orthognathic surgery. This is combined with a low reoperation rate. This may point to a patient benefit from high volume orthognathic centres.

Comprehensive Analysis of Mandibular Residual Asymmetry after Bilateral Sagittal Split Ramus Osteotomy Correction of Menton Point Deviation

Purpose

Facial asymmetry often persists even after mandibular deviation corrected by the bilateral sagittal split ramus osteotomy (BSSRO) operation, since the reference facial sagittal plane for the asymmetry analysis is usually set up before the mandibular menton (Me) point correction. Our aim is to develop a predictive and quantitative method to assess the true asymmetry of the mandible after a midline correction performed by a virtual BSSRO, and to verify its availability by evaluation of the post-surgical improvement.

Patients and Methods

A retrospective cohort study was conducted at the Hospital of Stomatology, Sun Yat-sen University (China) of patients with pure hemi-mandibular elongation (HE) from September 2010 through May 2014. Mandibular models were reconstructed from CBCT images of patients with pre-surgical orthodontic treatment. After mandibular de-rotation and midline alignment with virtual BSSRO, the elongation hemi-mandible was virtually mirrored along the facial sagittal plane. The residual asymmetry, defined as the superimposition and boolean operation of the mirrored elongation side on the normal side, was calculated, including the volumetric differences and the length of transversal and vertical asymmetry discrepancy. For more specific evaluation, both sides of the hemi-mandible were divided into the symphysis and parasymphysis (SP), mandibular body (MB), and mandibular angle (MA) regions. Other clinical variables include deviation of Me point, dental midline and molar relationship. The measurement of volumetric discrepancy between the two sides of post-surgical hemi-mandible were also calculated to verify the availability of virtual surgery. Paired t-tests were computed and the P value was set at .05.

Results

This study included 45 patients. The volume differences were 407.8±64.8 mm³, 2139.1±72.5 mm³, and 422.5±36.9 mm³; residual average transversal discrepancy, 1.9 mm, 1.0 mm, and 2.2 mm; average vertical discrepancy, 1.1 mm, 2.2 mm, and 2.2 mm (before virtual surgery). The post-surgical volumetric measurement showed no statistical differences between bilateral mandibular regions.

Conclusions

Mandibular asymmetry persists after Me point correction. A 3D quantification of mandibular residual asymmetry after Me point correction and mandible de-rotation with virtual BSSRO sets up a true reference mirror plane for comprehensive asymmetry assessment of bilateral mandibular structure, thereby providing an accurate guidance for orthognathic surgical planning.

Evaluation of condylar surface CT values related to condylar height reduction after orthognathic surgery

This study was performed to evaluate the relationship between condylar height reduction and changes in condylar surface computed tomography (CT) values in jaw deformity patients following orthognathic surgery. Mandibular advancement by sagittal split ramus osteotomy (SSRO) with Le Fort I osteotomy was performed in class II patients, and mandibular setback by SSRO with Le Fort I osteotomy was performed in class III patients. The maximum CT values (pixel values) at five points on the condylar surface and the condylar height, ramus height, condylar square, ramus angle, and gonial angle in the sagittal plane were measured preoperatively and 1 year postoperatively. Disc position was classified as anterior disc displacement (ADD) or other types by using magnetic resonance imaging (MRI). Ninety-two condyles of 46 female patients were prepared for this study. Their temporomandibular joints (TMJs) were divided into two groups based on class (46 joints in class II and 46 joints in class III) and two groups based on the findings (25 joints with ADD and 67 joints with other findings). ADD with and without reduction was observed in two joints in the class III group and in 23 joints in the class II group. The distribution of ADD incidence had not changed 1 year after surgery. Condylar height decreased 1 year after surgery in both class II patients (mandibular advancement) (p < 0.0001) and class III patients (mandibular setback) (p = 0.0306). Similarly, condylar height decreased 1 year after surgery both in patients who showed ADD (p = 0.0087) and those with other types (p = 0.0023). Significant postoperative increases at all angle sites on the condylar surface were found in the class II (p < 0.05) and ADD (p < 0.05) groups. This study showed that an enhanced condylar surface CT value might be one sign of condylar height reduction related to sequential condylar resorption, in combination with ADD.

Postoperative changes in mandibular position after mandibular setback surgery via the surgery-first approach in relation to the increase of vertical dimension and the amount of mandibular setback

OBJECTIVES

This study aimed to compare preoperatively predicted rotational relapse with actual post-treatment mandibular position after mandibular setback surgery via the surgery-first approach and to evaluate the effect of the increase of vertical dimension (VD) on surgical occlusion and the amount of mandibular setback on postoperative mandibular positional changes.

STUDY DESIGN

Twenty-nine patients who underwent bilateral sagittal split ramus osteotomy for mandibular prognathism were evaluated by using lateral cephalograms, which had been obtained preoperatively, immediately postoperatively, and immediately after debonding. Increase of VD on surgical occlusion was measured preoperatively. We estimated the mandibular forward movement resulting from the postoperative mandibular anticlockwise rotation during postoperative orthodontic treatment and compared it with the actual post-treatment mandibular position.

RESULTS

The actual postoperative mandibular forward movement (2.1 mm) was significantly greater compared with the forward movement (1 mm) predicted preoperatively (P < .01). The postoperative mandibular forward movement was greater in the groups with greater VD increase (>1.5 mm) or greater mandibular setback (>10 mm), even though there was no statistically significant difference.

CONCLUSIONS

These results suggest that additional postoperative relapse may occur with mandibular rotational relapse, and VD increase and the amount of mandibular setback may affect post-treatment mandibular position in surgery-first orthodontic treatment.

Midfacial soft tissue changes after leveling Le Fort I osteotomy with differential reduction. Cone-beam computed tomography volume superimposition

OBJECTIVE

To compare the short- and long-side soft tissue changes in the midfacial areas of patients who have undergone superior repositioning Le Fort I osteotomies for the correction of occlusal cant. The null hypothesis was that there were no significant differences in the midfacial soft tissue changes between the greater- and lesser-reduction sides.

MATERIALS AND METHODS

The subjects included 25 patients who had undergone Le Fort I osteotomy with superior repositioning and mandibular setback sagittal split ramus osteotomy. Using the cone-beam computed tomography volume superimposition method, the soft tissue changes were measured and determined both preoperatively and postoperatively. A 10 × 27 grid at 4.5-mm (vertical) and 5-mm (horizontal) intervals was used for the hard to soft tissue response.

RESULTS

The mean difference in the reduction from leveling Le Fort I osteotomy was 3.2 ± 1.2 mm between the short and long sides (P < .05). The mandibular setback movement averaged 5.4 ± 3.3 mm on the long side and 5.0 ± 3.6 mm on the short side (P > .05). The soft tissue areas below the Frankfort horizontal (FH) plane to 13.5 mm showed different changes after the differential leveling Le Fort I osteotomies.

CONCLUSIONS

The distinctly changed areas, which showed differences between the greater- and lesser-reduction sides beyond the 2.5-mm average for the soft tissue response, were below the FH plane to 13.5 mm and lateral to the midsagittal reference plane to 30 mm. In light of this, oral surgeons and orthodontists should be concerned about the volumetric midfacial difference after leveling the maxillary occlusal plane at the preoperative stage and thus should take appropriate measures to improve it.

Soft tissue outcome after mandibular advancement--an anthropometric evaluation of 171 consecutive patients

OBJECTIVES

There is an ongoing discussion in the literature about preoperative planning and postoperative evaluation of orthognathic surgery and its impact on facial appearance and aesthetics.

MATERIALS AND METHODS

We present an anthropometric and cephalometric evaluation of orthognathic surgery results based on reference anthropometric data. In 171 Class II patients, mandibular advancement by bilateral sagittal split osteotomy was performed. Preoperative as well as 3 and 9 months postoperative standardized frontal view and profile photographs and lateral cephalograms were evaluated in a standardized manner by use of 21 anthropometric indices. In cephalograms, SNA and SNB angle as well as Wits appraisal were investigated. Results of anthropometric and cephalometric measurements were correlated.

RESULTS

Lower vermilion contour, vermilion and cutaneous total lower lip height, nose-lower face height, nose-face height, upper face-face height, upper lip- and chin-mandible height index showed significant pre- to postoperative changes as well as SNB angle and Wits appraisal. Furthermore, medial-lateral cutaneous upper lip height, vermilion and cutaneous total lower lip height and philtrum-mouth width index presented significant correlations to cephalometric measurements.

CONCLUSIONS

The investigated anthropometric indices and cephalometric measurements presented reproducible results related to surgery. The correlation of cephalometric to anthropometric measurements has been proven useful for preoperative planning and postoperative evaluation of orthognathic surgery patients.

CLINICAL RELEVANCE

The presented anthropometric measurements and their observed correlation to cephalometric measurements could lead to a better prediction and optimized planning of the soft tissue result in orthognathic surgery patients and thereby improve the aesthetic outcome.

The use of SPHARM-PDM and mean latitude axis to evaluate airway changes

OBJECTIVE

To introduce new 3-D imaging techniques to characterize shape and volume changes of the oropharyngeal space after bilateral sagittal split osteotomy (BSSO) advancement.

MATERIALS AND METHODS

Longitudinal cone-beam computed tomography (CBCT) scans were obtained for 20 patients undergoing BSSO advancement at three time points (T1 = presurgery, T2 = splint removal, and T3 = 1 year after surgery). Segmentation of the airway was performed using the following boundaries: hard palate/posterior nasal spine superiorly and lower border of C3 to the base of the epiglottis inferiorly. For shape measurements, point-based correspondent models and mean latitude axis were obtained for all the data using SPHARM-PDM software. All 3-D correspondent models were rigidly registered using Procrustes alignment. Absolute distance maps and corresponding vector maps were calculated to show shape and vector differences between each correspondent point. Mean latitude axis is a new imaging method to calculate minimum cross-sectional areas along the long axis of the airway independent of head position/alignment.

RESULTS

The airway volume increased (P < .01) after BSSO advancement (2973.9 mm³ ± 27882.0) and was stable (-439.9 mm³ ± 3308.8) 1 year post-op. 3-D color maps and semitransparency overlays showed more lateral than anteroposterior expansion of the airway after BSSO advancement. Mean latitude axis was used to measure minimum cross-sectional area, showing a statistically significant increase (52.7 mm² ± 46.7) (P < .01) after surgery and remained stable (-10.3 mm² ± 43.3) 1 year after surgery.

CONCLUSIONS

SPHARM-PDM and mean latitude axis are useful tools to assess airway shape change. BSSO advancement produces a significant increase in pharyngeal airway volume and minimum cross-sectional area. The airway space increased more transversely than anteroposteriorly.

Evaluation of Condylar Positional, Structural, and Volumetric Status in Class III Orthognathic Surgery Patients

BACKGROUND AND OBJECTIVES

The need to evaluate the condylar remodeling after orthognathic surgery, using three-dimensional (3D) images and volume rendering techniques in skeletal Class III patients has been emphasized. The study examined condylar positional, structural, and volumetric changes after bimaxillary or single-jaw maxillary orthognathic surgeries in skeletal Class III patients using the cone-beam computed tomography.

MATERIALS AND METHODS

Presurgical, postsurgical, and one-year post-surgical full field of view (FOV) cone-beam computed tomography (CBCT) images of 44 patients with skeletal Class III deformities were obtained. Group 1 underwent a bimaxillary surgery (28 patients: 24 females and 4 males), with mean age at the time of surgery being 23.8 ± 6.0 years, and Group 2 underwent maxillary single-jaw surgery (16 patients: 8 females and 8 males), with mean age at the time of surgery being 23.7 ± 5.1 years. After the orthognathic surgery, the CBCT images of 88 condyles were evaluated to assess their displacement and radiological signs of bone degeneration. Three-dimensional (3D) condylar models were constructed and superimposed pre- and postoperatively to compare changes in condylar volume.

RESULTS

Condylar position was found to be immediately altered after surgery in the maxillary single-jaw surgery group, but at the one-year follow-up, the condyles returned to their pre-surgical position. There was no significant difference in condylar position when comparing between pre-surgery and one-year follow-up in any of the study groups. Condylar rotations in the axial and coronal planes were significant in the bimaxillary surgery group. No radiological signs of condylar bone degeneration were detected one year after the surgery. Changes in condylar volume after surgery were found to be insignificant in both study groups.

CONCLUSIONS

At one year after orthognathic surgery, there were no significant changes in positional, structural, or volumetric statuses of condyles.

Bone healing after Le Fort I osteotomy with SSRO, using uHA/PLLA plates and screws, in class II and III patients

PURPOSE

The purpose of this study was to compare bone healing after Le Fort I osteotomy with sagittal split ramus osteotomy (SSRO) in class II and class III patients.

PATIENTS AND METHODS

The subjects consisted of 46 Japanese class II and III patients. Le Fort I osteotomy was performed in combination with SSRO. They were divided into two groups (23 class II cases and 23 class III cases). Four absorbable plates (uncalcined and unsintered hydroxyapatite and poly-l-lactic acid - uHA/PLLA) and screws were used to fix the maxillary segment in all patients, in the same manner. Postoperative computed tomography (CT) was analyzed for all patients at 1 week and 1 year postoperatively. The anterior and lateral areas between the maxillary segments were measured using two-dimensional frontal and lateral views from the three-dimensional images reconstructed over a constant CT value.

RESULTS

There were no significant differences in the area of bone defect healing between classes II and III at 1 year postoperatively, although there were significant differences between the two groups at 1 week postoperatively (p < 0.05). Furthermore, there were no significant differences in the areas of bone defect between 1 week and 1 year postoperatively, in both groups.

CONCLUSION

Using measurements based on CT value threshold within 1 year after Le Fort I osteotomy, this study suggests that the areas of bony defect in the region of the anterior and lateral walls of the maxilla do not always decrease in both classes II and III.

Influence of anatomic position and intraoperative exposure of the inferior alveolar nerve on neurosensory disturbance after sagittal split ramus osteotomy: a three-dimensional computed tomography study

OBJECTIVE

To evaluate the influence of the anatomic position and intraoperative exposure of the inferior alveolar nerve on neurosensory disturbance (NSD) in sagittal split ramus osteotomy.

STUDY DESIGN

The anatomic factors of the nerve were measured on preoperative three-dimensional computed tomography in 98 patients. The intraoperative nerve exposure was assessed. NSD was evaluated for 1 year after surgery. The correlations between NSD and the factors were analyzed.

RESULTS

The NSD decreased as the lateral marrow space from the nerve increased (P < .01). The complete nerve exposure increased NSD by 7.6 times (P = .01). The nerve exposure increased as the buccal plate thickness increased (P = .01) and decreased as the vertical marrow space from the nerve increased (P = .01).

CONCLUSIONS

The nerve exposure and the lateral marrow space from the nerve affected NSD. The buccal plate thickness and the vertical marrow space indirectly affected NSD through nerve exposure.

Is Atypical Swallowing Associated With Relapse in Orthognathic Patients? A Retrospective Study of 256 Patients

PURPOSE

To determine the association of atypical swallowing (AS) with relapse in patients undergoing combined orthodontic and orthognathic treatment.

MATERIALS AND METHODS

In this retrospective cohort study, the clinical data of all patients who underwent combined surgical and orthodontic treatment from 1998 through 2015 at the University Hospital of Geneva (Geneva, Switzerland) were reviewed. The primary outcome variables were 1) AS and 2) post-treatment relapse. Other variables included, age, gender, dentofacial deformity (facial asymmetry, mandibular deficiency, mandibular excess, maxillary retrusion, open bite), surgical procedure performed (bilateral sagittal split osteotomy [BSSO] with or without Le Fort I osteotomy), and dental interocclusal relations according to Angle.

RESULTS

Of the 256 patients investigated, 23 (9%) showed relapse at 1 year after treatment. Multivariate analysis showed that AS status (before treatment, odds ratio [OR] = 9.44, P = .005; after treatment, OR = 56.17, P < .001; before and after treatment, OR = 20.49, P < .001) was significantly associated with relapse. The presence of a pretreatment open bite also was associated with an increased risk of relapse (OR = 0.04, P < .001) regardless of AS status.

CONCLUSION

The present study showed that in orthognathic patients 1) AS was associated with relapse regardless of dentofacial deformity or surgical procedure performed and 2) AS can appear after treatment in patients who were initially free of it.

Facial Contour Refining after Surgery-First SSRO with Computer-Assisted Design in East Asians

BACKGROUND

Surgery-first sagittal split ramus osteotomies (SF-SSRO) are an effective treatment for patients with dental malocclusion. However, some patients with mandibular prognathism usually have facial deficiencies which cannot be corrected completely after orthognathic surgery. These are not accepted because the remaining facial contours are in disharmony.

METHODS

Twenty-five patients, who were unsatisfied with their appearances after SF-SSRO and orthodontics, were included. The preoperative CTs were used to investigate patients for facial deformity. To achieve a harmonious facial contour, mandible long-curve osteotomy/mandible U-shaped osteotomy, genioplasty or facial autologous fat grafting was selected depending on patients' contour deformities with the assistance of CAD.

RESULTS

Among the patients who underwent osteotomy, the gonial angle was improved from 111.16° ± 9 to 111.58° ± 9.06 after SF-SSRO because of distal fragment setback and rotation. After facial refine surgery, the gonial angle was significantly increased to 121.69°±2.41 (p < 0.05). And the mandibular width was decreased from 11.29 cm ± 0.44 to 10.45 cm ± 0.39 (p < 0.05) after mandibular outer plate griding. All patients were shown no signs of infection, massive bleeding, and osteonecrosis in the early stage. After follow-up time, they were all satisfied with their results and most of them recovered from lip numbness.

CONCLUSIONS

This study indicated the clinical feasibility of two-stage orthognathic and facial bone contouring surgery for the treatment of dentofacial deformities. Two-stage facial contouring surgery can provide esthetic improvement for more accuracy in refining the facial contour.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Does the use of a piezoelectric saw improve neurosensory recovery following sagittal split osteotomy?

Neurosensory disturbance of the inferior alveolar nerve (IAN) is an adverse effect associated with sagittal split osteotomies (SSO). The purpose of this work was to evaluate neurosensory recovery of the IAN when SSOs were performed with piezoelectric (PZ) versus reciprocating (RP) saws. This was a prospective split-mouth study of patients undergoing bilateral SSO using a PZ saw on one side and an RP saw on the other. The primary outcome of interest was neurosensory recovery, as assessed using the functional sensory recovery (FSR) scale defined by the UK Medical Research Council. Descriptive, bivariate, and regression statistics were computed. Twenty patients (40 SSOs) with a mean age of 19.9 ± 3.2 years were included. The mean mandibular movement did not differ significantly (P = 0.50) between the PZ and RP groups. All patients achieved FSR within 1 year of surgery (range 34-249 days). The median time to FSR overall was comparable between the PZ and RP groups (94.5 days and 101.5 days, respectively; P = 0.20). However, at the time FSR was achieved, PZ SSO sites were more likely to have higher neurosensory scores when compared to RP SSO sites (hazard ratio 2.3, 95% confidence interval 1.1-4.9, P = 0.04).

Long-term follow-up of intersegmental displacement after orthognathic surgery using cone-beam computed tomographic superimposition

OBJECTIVES

To evaluate intersegmental displacement during long-term follow-up after bilateral sagittal split osteotomy (BSSO) by mandibular body area superimposition.

MATERIALS AND METHODS

Cone-beam computed tomography (CBCT) images of 23 patients ages 18-37 years with class III malocclusion before orthognathic surgery were obtained. A three-dimensional (3D) CBCT examination was performed at four stages: surgery (T0), 6 months after surgery (T1), 1 year after surgery (T2), and long-term follow-up (6.1 ± 2.1 years, T3). The CBCT datasets were superimposed on the symphyseal area and the lower part of the distal segment of the mandible between T0 and the other time points (T1, T2, and T3). The reference points (both condyle, coronoid, and sigmoid) were estimated by the CBCT analyzed program.

RESULTS

The coronoid, condylion, and sigmoid showed changes within 6 months after surgery, but there was no significant change in the intersegmental displacement between 6 months and 6 years after surgery. The distances between the left and right coronoid, condylion, and sigmoid from T0 to T3 were noted.

CONCLUSIONS

The change in intersegmental displacement between T0 and T3 affecting relapse after orthognathic surgery was not significantly different. This suggests that the mandible itself may have a stable morphology during the follow-up period.

Changes in the position of the condyle after bilateral sagittal split ramus osteotomy in patients with mandibular retrusion and protrusion: a new condyle: fossa matching concept

The purpose of this study was to compare the condylar positional changes after bilateral sagittal split ramus osteotomy (BSSRO) in patients with mandibular retrusion and those with mandibular prognathism. We also studied the correlation between the degree of matching of the condyle and fossa, and condylar displacement. Thirty patients with mandibular retrusion (n=11) or mandibular prognathism (n=19) who underwent BSSRO were included. The condylar position was assessed from spiral computed tomographic (CT) scans taken preoperatively, during the first postoperative week, and at least 6 months postoperatively. All data were measured by MIMICS 17.0 and analyzed by Student's t test and Pearson's correlation analysis. The size of the condyles of patients with mandibular retrusion was significantly less than those of patients with mandibular prognathism (491.5 (172.8) compared with 823.2 (212.0) mm³). The size of the glenoid fossa in those with mandibular retrusion (599.6 (110.4) mm³) and those with prognathism (597.6 (151.6) mm³) did not seem to differ. Postoperatively the condyles moved outwards, backwards, and downwards in both groups of patients. Correlation analysis between the condyle:fossa volume ratio and the condylar positional changes showed that a large condyle:fossa volume ratio correlated with the smaller positional changes in the condyle. The condylar position changed immediately after mandibular advancement and setback, and persisted in the long term. Larger condyles tended to have fewer positional changes.

Excessive gingival display treated with 2-piece segmental Le Fort I osteotomy: A case report

BACKGROUND

The demand for orthognathic surgery has increased worldwide. Women with jaw deformity tend to have a worse quality of life than men owing to the deformity's negative effects on body image, low self-esteem, lack of self-confidence, and dissatisfaction with life. Therefore, they wish for more reliable treatment options.

CASE DESCRIPTION

A woman aged 25 years and 9 months sought treatment for a convex profile and excessive gingival display caused by a skeletal Class II jaw-base relationship. Gingival exposure was up to 6.5 millimeters at full smile. She chose orthognathic surgery, and the authors performed a 2-piece segmental Le Fort I osteotomy and bilateral sagittal split ramus osteotomy. After active orthodontic treatment, the protrusive profile was improved, and an acceptable occlusion and an attractive smile were achieved.

PRACTICAL IMPLICATIONS

It is hoped that 2-piece segmental Le Fort I osteotomy becomes a common treatment option for patients with protrusive profiles and excessive gingival displays.

Sonographic Evaluation of Bone Formation After Sagittal Split Ramus Osteotomy

OBJECTIVES

The aim of this study was to assess the applicability of sonography for evaluation of mandible bone healing after orthognathic surgery.

METHODS

The study included 10 patients who underwent orthognathic surgery. To assess new bone formation after sagittal split ramus osteotomy, the echo intensities of ultrasound (US) reflections of the proximal segment, distal segment, and bone gap were measured with a real-time US scanner at 1 day, 1, 2, 3, and 4 weeks, and 2 and 4 months postoperatively.

RESULTS

The mean echo intensity of US reflections of the bone gap gradually increased and became equivalent to that of bone surfaces by 4 weeks postoperatively. X-ray tomograms confirmed bone formation at the bone gap at the same time.

CONCLUSIONS

This study indicates that sonography may be useful for evaluating osseous healing after orthognathic surgery.

Evaluation of volume change in oral cavity proper before and after mandibular advancement

OBJECTIVES

To evaluate the tongue and oral cavity proper volume in pre- and post-bilateral sagittal split osteotomy (BSSO) patients, and to establish whether there was a correlation between them.

MATERIALS AND METHODS

A retrospective study that evaluated 12 patients' pre- and post-surgical computed tomography records satisfying the inclusion criteria. Borders were defined for measurement of tongue and oral cavity proper volume. The volume assessment was carried out using 3D slice software.

RESULTS

The mean difference of tongue volume was 5.7 ± 1.7 cm3, which showed high statistical significance. The mean difference of oral cavity proper volume (OCVP) was 6.9 ± 3.4 cm3 and indicated high statistical significance. A very strong positive correlation existed between pre- and post-surgical tongue volume. Positive correlation was also evident between pre and post - surgical OCVP. Medium positive correlation was noted when the difference between pre- and post-surgical tongue and OCVP were assessed.

CONCLUSIONS

There was a significant change in volume of tongue and oral cavity proper after BSSO advancement surgery. The space around the tongue, position of tongue, and maxillary and mandibular relationship influence the volume of tongue and oral cavity proper.

Evaluation of the Therapeutic Effect of Bi-Maxillary Osteotomy Using the Stress Distribution on the Temporomandibular Joint When Doing Anterior Teeth Occlusion

The purpose of this study was to investigate how sagittal split ramus osteotomy (SSRO) and Le Fort 1 osteotomy affected the stress distribution of the temporomandibular joint (TMJ) during an anterior teeth bite using the three-dimensional (3D) finite element (FE) method. Fourteen orthognathic surgery patients were examined with mandibular prognathism, facial asymmetry, and mandibular retraction. They underwent Le Fort 1 osteotomy in conjunction with SSRO. In addition, ten asymptomatic subjects were recruited as the control group. The 3D models of the mandible, disc, and maxilla were reconstructed according to cone-beam computed tomography (CBCT). Contact was used to simulate the interaction of the disc-condyle, disc-temporal bone, and upper-lower dentition. Muscle forces and boundary conditions corresponding to the anterior occlusions were applied on the models. The stresses on the articular disc and condyle in the pre-operative group were significantly higher than normal. The contact stress and minimum principal stress in TMJ for patients with temporomandibular disorder (TMD) were abnormally higher. The peak stresses of the TMJ of the patients under anterior occlusions decreased after bimaxillary osteotomy. No postoperative TMD symptoms were found. Maxillofacial deformity led to excessive stress on the TMJ. Bimaxillary osteotomy can partially improve the stress distributions of the TMJ and relieve the symptoms of TMD.

Are condylar morphologic changes associated with temporomandibular disorders in patients with orthognathia?

OBJECTIVE

To determine the association between morphologic condylar changes and temporomandibular disorders (TMDs) in patients with orthognathia.

STUDY DESIGN

Data from 89 patients were analyzed. TMDs were classified according to the Research Diagnostic Criteria for TMDs. TMD severity was scored according to the Helkimo indices. Calculation of the condylar area, perimeter, and height was performed by using a specific computational method including panoramic radiography.

RESULTS

Sixty-five (73%) patients presented with morphologic condylar changes. Decreases in condylar perimeter and area were found to be predictors of postoperative TMDs (P = .009; odds ratio [OR] = 3.66) and disk displacement (P = .008; OR = 4.43), respectively. Condylar area and height decreases were associated with worsening of TMDs (P = .03 and 0.04).

CONCLUSIONS

This study demonstrated that in orthognathic patients, postoperative condylar changes are associated with postoperative TMDs as well as with the degree of TMD severity and that preoperative TMDs are associated with such condylar changes.