Bimaxillary Surgery Research Articles

Does the Sequence of Bimaxillary Orthognathic Surgery Affect Accuracy in Skeletal Class III Patients?

BackgroundIt is necessary to determine whether the sequence of maxillary and mandibular surgeries in bimaxillary orthognathic surgery affects the accuracy of surgical outcomes. PurposeThe study aimed to measure and compare the accuracy among patients who underwent maxilla-first versus mandible-first bimaxillary surgery to correct a class III skeletal pattern. Study designThis retrospective cohort study included consecutive patients treated by a single surgeon at one center using Le Fort I and bilateral sagittal split osteotomy surgery. Exclusions included patients scheduled for one-jaw or maxilla-segmental surgery and those with craniofacial syndromes, such as clefts. Predictor variableThe predictor variable was operative sequence for bimaxillary operations, divided into maxilla- or mandible-first groups. Outcome variableThe outcome variable was accuracy, measured using linear discrepancies between landmarks in the virtual plan and actual operative outcomes. The measurement of linear discrepancy that was closer to 0 was considered the more accurate result. CovariatesSex, age, maxilla sagittal rotation degree, amount of posterior maxilla impaction, mandibular autorotation (°), and intermediate splint thickness (mm) were the covariates. AnalysesStatistical analysis was performed using Student’s t-test and Pearson’s correlation, with statistical significance set at P < 0.05. ResultsThe sample comprised 60 patients with a mean age of 22.8 ± 3.7 years, of whom 36 (60%) were male. In the maxilla-first group, there were 30 subjects (60% male; mean age: 23.1 ± 4.2 years), with a mean mandibular autorotation of 0.41° (range: 0°–2.5°). The mandible-first group comprised 30 patients (60% male; mean age: 22.6 ± 3.3 years), with a mean mandibular autorotation of 5.46° (range: 1.9°–9.2°). The linear discrepancies for all landmarks did not significantly differ between mandible- and maxilla-first groups (P > 0.18). The mean 3D discrepancies for all landmarks in maxilla-first group was 1.23 ± 0.5 mm and 1.23 ± 0.33 mm in mandible-first group, with no significant difference observed between the groups (P > 0.98). The amount of mandibular autorotation for intermediate splint application showed no significant correlation with the linear discrepancies (P > 0.58). ConclusionsIn patients with skeletal class III malocclusion, mandible-first surgery in bimaxillary orthognathic surgery demonstrates accurate outcomes comparable to maxilla-first surgery.

Can the Upper Vermilion and the Nasolabial Fold Be Changed With Orthognathic Surgery?

BackgroundRetrusive profiles show an appearance of aging with an under-projected vermilion and pronounced nasolabial folds due to deficient bone support. PurposeA study was made of the association between orthognathic surgery and changes in the nasolabial and vermilion areas in patients with retrusive profiles. Study design, setting, sampleA retrospective cohort study evaluated patients subjected to bimaxillary surgery according to the Barcelona Line (BL) protocol during 2021 at Teknon Medical Center (Barcelona, Spain). Subjects with craniofacial syndromes, facial aesthetic procedures, and dental rehabilitations involving lip changes, were excluded. Predictor variableThe predictor variable was the timing of cephalometric measures, reported as T0 (preoperatively), T1 (one month after surgery), and T2 (after one year of follow-up). Main outcome variableThe outcome variable corresponded to the soft tissue changes of the nasolabial and vermilion area, reported as the nasolabial fold length and angle, nasolabial angle, upper lip concavity, vermilion length, and upper lip sagittal distance from BL. CovariatesThe covariates comprised patient demographic data, the surgical-orthodontic protocol, and the magnitude and direction of the skeletal movements. AnalysesDescriptive and inferential analyses were performed based on analysis of variance (ANOVA), the Bonferroni test, Pearson’s linear coefficient, the nonparametric Mann-Whitney U-test, Kruskal-Wallis test, and multiple linear regression models. Statistical significance was considered for p < 0.05. ResultsThe sample comprised 27 subjects with a mean age of 32.5 ± 11.2 years. A mean decrease in nasolabial angle of 5.5 ± 6º was recorded (p < 0.001), with a shortening of the nasolabial fold length of 4.4 ± 7.6 mm (p=0.019). An increase in upper lip concavity angle of 14.4 ± 12º was recorded (p < 0.001), along with a vermilion lengthening of 1.6 ± 1.3 mm (p < 0.001) and an increase in upper lip sagittal distance to BL of 5.7 ± 7.3 mm (p=0.001), indicating a more projected and everted upper vermilion. Conclusions and relevanceWhen adequate dentoskeletal support is provided by specific positional changes of the jaws planned through orthognathic surgery, the length of the nasolabial fold decreases, and the upper vermilion lengthens and becomes slightly everted.

Bone microstructural characteristics or positional changes of condyle head affect short-term condyle head resorption after orthognathic surgery

Condylar resorption occurs in some cases after orthognathic surgery, and the risk factors associated with postoperative condylar head resorption have been extensively described. Nevertheless, even in cases with a combination of risk factors, postoperative condylar resorption may not appear. This study analyzed the microstructure and three-dimensional positional change of the condylar bone via imaging in patients who have undergone bimaxillary orthognathic surgery to determine whether the microstructure or condylar position differs between patients with and without postoperative condylar resorption. Among asymptomatic patients who underwent bimaxillary surgery between April 2021 and March 2022 at our department, 17 patients were analyzed, limited to “female,” “skeletal Class II,” and “high-angle cases,” which are known risk factors for mandibular head resorption. Multidetector computed tomography was performed on these patients before and 6 months after surgery, and the bone microstructure of the condylar head and the three-dimensional positional changes of the condylar bone and the proximal bony fragments were compared with the presence of postoperative condyle resorption using the bone morphology software TRI/3D-BON. Patients with condylar bone abnormalities before surgery and those with high trabecular bone density can develop postoperative resorption if the condyle is misaligned by surgery.

Changes in Maxillary Sinus Volume and Mucosal Thickness Post Bimaxillary Advancement Procedures: A Retrospective Study

Background: Bimaxillary surgery is an elemental procedure in the field of cranio-maxillofacial surgery. It allows for the correction of even the most challenging cases of maxillomandibular disorders, malocclusion, facial asymmetry, and disproportion. The osteotomies and maneuvers carried out during the procedure result in changes to the surrounding tissues, including the maxillary sinuses (MS). The aim of this study was to assess the change in the maxillary sinus volume and the thickness of the mucosa after maxillomandibular advancement (MMA) surgeries. Methods: A group of 25 patients who underwent MMA surgery were included in the study. Computed tomography (CT) of the head and neck region was performed 2 weeks preoperatively and 6 months postoperatively. Acquired Digital Imaging and Communications in Medicine (DICOM) files were analyzed using different software programs to calculate the medium MS mucosa thickness and MS volume. Results: A statistically significant reduction in MS volume was observed (p = 0.015). The change in the median thickness of the MS mucosa was not statistically significant. The median sella-nasion-A point angle (SNA angle) value of the group increased from 80.2 to 83.4 degrees. A weak negative correlation between the SNA delta and the MS volume delta was observed. Spearman’s rank coefficient: (ρ s = −0.381, p = 0.060). Conclusions: The MMA surgery results in a reduction in the MS volume. The amount of forward movement of the maxilla may be correlated with the extent of the MS volume reduction.

Hard to Soft Tissue Profile Changes in Skeletal Class III Dentofacial Deformities After Maxillary Advancement and Mandibular Setback Orthognathic Surgery

Objective To correlate the sagittal hard tissue movement and soft tissue changes among patients with skeletal class III malocclusion following bimaxillary orthognathic surgery. Material and Methods Fifty-nine subjects with skeletal class III malocclusion treated consecutively with maxillary advancement and mandibular setback were assessed for skeletal and soft tissue linear changes using presurgical (T1) and post-treatment (T2) lateral cephalograms. Pearson’s correlation coefficient test was used to correlate hard and soft tissue parameters. Results The sagittal hard tissue movement and soft tissue changes for all the parameters assessed in maxilla and mandible showed statistically significant correlations. The ratios of changes for the maxillary protrusion [N-A (HP)] to horizontal subnasale (Sn), superior labial sulcus (Sls), and labrale superioris (Ls) were 0.574:1, 0.703:1, and 0.721:1 respectively. The ratio of horizontal labrale inferioris (Li), mentolabial fold (Mlf), and soft tissue (Pg′) to mandibular protrusion [N-B (HP)] were 0.992:1, 0.970:1, and 0.590:1 respectively and to chin protrusion [N-Pg (HP)] were 1.293:1, 1.252:1, and 1.001:1, respectively. The ratios were different for males and females in maxilla and mandible. Conclusion Sagittal hard tissue movement and soft tissue changes are significantly correlated. The soft tissue movement in the mandible were more proportionate compared to the maxilla. The sagittal hard tissue to soft tissues movement ratios were greater in maxilla and lesser at pogonion and mentolabial sulcus in females compared to males. The ratios obtained can be used for predicting postsurgical soft tissue changes.

Three-Dimensional Changes of Condylar Position After Bimaxillary Surgery to Correct Skeletal III Malocclusion: Cone Beam Computed Tomography Voxel-Based Superimposition Analysis

BackgroundThe stability of the condylar position within the first three months after orthognathic surgery in patients with skeletal Class III malocclusion is crucial for subsequent orthodontic treatment. PurposeThe purpose was to compare condylar positional changes three months after bimaxillary surgery to correct skeletal Class III deformities, utilizing the conventional two-dimensional (2D) combined with the cone beam computed tomography (CBCT) voxel-based superimposition analysis. Study design, setting, sampleThis retrospective cohort study included skeletal Class III patients undergoing bimaxillary orthognathic surgery at Khon Kaen University, Thailand in 2020. Exclusion criteria were patients with temporomandibular disorder (TMD) symptoms, facial asymmetry prior to the surgery, or surgical complications. Exposure variableThe exposure variable was the timing, both preoperatively and 3 months postoperatively. This 3-month postoperative time point was chosen because complete healing of the bimaxillary surgery is expected by then, without any potential influence of condylar changes resulting from subsequent orthodontic treatment. Main outcome variablesThe outcome variable is condylar position measurement, joint space (mm) and axial condylar angle (degrees). CovariatesDemographics (age, sex), and surgical details (direction and amount of movement) were collected as covariates. AnalysesStatistical analysis of condylar positional changes and correlations was performed using paired t-test and linear correlation (P-value < 0.05), respectively. ResultsThe sample included 11 subjects (22 condyles), with a mean age of 24±5.24 years. Both 2D measurements and voxel-based 3D superimposition showed significant changes in condylar position three months after bimaxillary surgery: inferior (0.45±0.26 mm, P < 0.001), posterior (0.46±0.39 mm, P = 0.003), lateral (0.38±0.42 mm, P = 0.01) displacement, and inward rotation (5.21±2.54°, P < 0.001). No significant correlation was found between jaw movement distance and condylar changes. Conclusions and relevanceTo our knowledge, this is the first study to report measures of condylar changes at 3 months, when complete healing of the osteotomies would be expected, using Le Fort I osteotomy for maxillary advancement combined with bilateral sagittal split ramus osteotomy (BSSRO) for mandibular setback. These changes are small in magnitude and may be of little relevance to patient care.

“The impact of orthognathic surgery on articulation proficiency and speech intelligibility in skeletal Class III malocclusion: 18 months follow up”

IntroductionOrthognathic surgery results in the positional change of the maxilla and mandible that may affect speech. The present study evaluated the effect of combined maxillary advancement and mandibular setback surgery on articulation proficiency and speech intelligibility in patients with non-syndromic skeletal Class III malocclusion. MethodsIn this prospective study, twenty-five patients with skeletal class III malocclusion and consecutively treated with Lefort-1 maxillary advancement and mandibular setback (BSSO) orthognathic surgery were included in this study. The speech sample was recorded with a digital audio tape recorder one day before surgery and at 3, 6, 9, 12 and 18 months after surgery. Three qualified and experienced speech and language pathologists evaluated articulation errors and intelligibility of speech samples. Repeated One-way analysis of variance was used to compare articulation proficiency and speech intelligibility at different time intervals. ResultsThe substitution, omission, distortion and addition errors showed no significant changes at 3 months and 6 months. The total articulation errors decreased to zero at 9 months and no significant increase was observed till 18 months (P < 0.05). Speech intelligibility showed statistically non-significant improvement at any time interval. Cephalometric skeletal parameters SNA and N ḻ A°. were significantly correlated with addition and total articulation errors at 18 months follow up. ConclusionsThe ortho-surgical treatment improves speech (decreases. articulation errors) in most of the patients usually 6–9 months post-surgery. Speech intelligibility is not affected by bimaxillary orthognathic surgery in skeletal class III patients. The articulation errors were correlated to changes in position of maxilla.

Site and severity of facial asymmetry after bimaxillary surgery for class III deformity: a case-control study.

The study aimed (1) to evaluate the site and severity of facial asymmetry in Class III patients before and after bimaxillary surgery, and (2) to identify the influence of initial severity and positional jaw asymmetry on residual facial asymmetry. Preoperative and postoperative cone-beam computed tomography of 65 patients with Class III facial asymmetry who underwent bimaxillary surgery were evaluated. Five midline and 14 paramedian facial soft tissue landmarks were identified to assess facial asymmetry. The outcomes were compared to a control group consisting of 30 age- and gender-matched Class I subjects. The postoperative positional jaw asymmetry (i.e., shift, roll, yaw) of each osteotomy segment (maxilla, mandible, chin, ramus) was also measured. Before surgery, the asymmetry was more severe at the chin, middle and lower contour. Bimaxillary surgery effectively corrected facial asymmetry, particularly in achieving normalization of chin deviation. However, significant asymmetry persisted postoperatively in the middle and lower contour (p < 0.001 and p < 0.01, respectively), which was affected by the positional ramus asymmetry in the roll and shift. Deviation of the chin, middle and lower contour contributed significantly to overall facial asymmetry in Class III asymmetry. Despite normalization of the chin deviation after bimaxillary surgery, asymmetry persisted at the middle and lower contour, primarily as the result of insufficient correction of the positional ramus asymmetry. Understanding the residual asymmetry after bimaxillary surgery is important for minimizing deviation and optimizing the surgical planning for its correction.

Stability between single and segmental maxillary osteotomies in bimaxillary surgery for cleft-associated class III deformity: a CBCT study.

Segmental Le Fort I osteotomy through the cleft is a common strategy to narrow the alveolar cleft in adults. This study compared skeletal stability between single and segmental Le Fort I osteotomies in patients with unilateral cleft lip and palate (UCLP). This retrospective analysis examined 45 adults with complete UCLP-associated class III deformities who underwent bimaxillary surgery with either single (n = 30) or segmental (n = 15) Le Fort I advancement. Cone beam computed tomography (CBCT) scans of the facial skeleton were acquired before surgery, 1-week postsurgery, and at follow-up. Measures of landmarks from the CBCT images for the two treatment groups were compared for translation (left/right, posterior/anterior, superior/inferior) and rotation (yaw, roll, pitch). Postsurgery, the downward movement of the maxilla was larger in the segmental group than the single group. At follow-up, the maxilla moved backward in both groups, and upward in the segmental group. The mandible moved forward and upward and rotated upward in both groups. The amount of upward movement and rotation was larger in the segmental group than the single group. Two years after bimaxillary surgery in patients with UCLP-associated class III deformity, greater relapse was found after segmental Le Fort I osteotomies in vertical translation of the maxilla and mandible, and pitch rotation of the mandible compared with single Le Fort I osteotomies. The vertical relapse of the maxilla was larger after segmental Le Fort I advancement compared with single Le Fort I advancement in clefts.

Evaluation of a Fully Digital, In-House Virtual Surgical Planning Workflow for Bimaxillary Orthognathic Surgery

The advantages of virtual surgical planning (VSP) for orthognathic surgery are clear. Previous studies have evaluated in-house VSP; however, few fully digital, in-house protocols for orthognathic surgery have been studied. The purpose of this study was to evaluate the difference between the virtual surgical plan and actual surgical outcome for orthognathic surgery using a fully digital, in-house VSP workflow. This is a prospective cohort study from September 2020 to November 2022 of patients at the Victoria General Hospital in Halifax, NS, Canada who underwent bimaxillary orthognathic surgery. Patients were excluded if they had previously undergone orthognathic surgery or were diagnosed with a craniofacial syndrome. The primary outcome variables were the mean 3-dimensional (3D) (Euclidean) distance error, as well as mean error and mean absolute error in the transverse (x axis), vertical (y axis), and anterior-posterior (z axis) dimensions. Covariates included age, sex, and surgical sequence (mandible-first or maxilla-first). The primary outcome was tested using Z and t critical value confidence intervals. The P value was set at .05. The 3D distance error for mandible-first and maxilla-first groups was compared using a 2-sample t-test as well as analysis of variance. The study sample included 52 subjects (24 males and 28 females) with a mean age of 27.7 (± 12.1) years. Forty three subjects underwent mandible-first surgery and 9 maxilla-first surgery. The mean absolute distance error was largest in the anterior-posterior dimension for all landmarks (except posterior nasal spine, left condyle, and gonion) and exceeded the threshold for clinical acceptability (2mm) in 16 of 23 landmarks. Additionally, mean distance error in the anterior-posterior dimension was negative for all landmarks, indicating deficient movement in that direction. The effect of surgical sequence on 3D distance error was not statistically significant (P=.37). In general, the largest contributor to mean 3D distance error was deficient movement in the anterior-posterior direction. Otherwise, mean absolute distance error in the vertical and transverse dimensions was clinically acceptable (< 2mm). These findings were felt to be valuable for treatment planning purposes when using a fully digital, in-house VSP workflow.

Does Condylar Morphology Affect Maxillary Repositioning in Bimaxillary Orthognathic Surgery?

This study aimed to measure the association between condylar morphology and a measure of the maxillary centroid following bimaxillary surgery using mandibular-dependent splints. The study included skeletal Class III and Class II malocclusion patients, excluding those with facial asymmetry. Based on computed tomography imaging patients were characterized into normal or abnormal temporomandibular joint (TMJ) groups. A computer-aided design/computer-aided manufacturing splints were fabricated to reposition the maxilla in Le Fort I osteotomy. The primary outcome measure was the absolute differences between the maxillary centroid's the planned and actual postoperative positions calculated by superimposing computed tomography scans. The secondary outcome was the measure of other variations in linear and angular maxilla discrepancies. The demographic covariates included the age and sex of the patients. The operative covariates consisted of the dentofacial deformity and the planned movement of the maxilla. Seventy patients with skeletal maxillofacial deformities were included for analysis: 44 patients in the normal and 26 in the abnormal TMJ group. The average maxillary misalignment was 1.04±0.48mm in the normal and 1.53±0.63mm in the abnormal TMJ group (P<0.001). A statistically significant relationship existed between the discrepancies of the maxillary centroid and dentofacial deformity (η=0.656, P<0.001). These findings suggest an increased propensity for maxillary malposition in skeletal Class II patients. Furthermore, condylar morphology is a significant prognostic factor influencing maxillary repositioning errors in bimaxillary surgery with mandibular-dependent splints.

Comprehensive 3-dimensional Positional and Morphological Analyses of Condyle and Glenoid Fossa in Patients with Skeletal Class II Malocclusion following Bimaxillary Orthognathic Surgery.

This study aimed to comprehensively and quantitatively characterize 3-dimensional (3D) positional and morphological changes of the condyle and glenoid fossa in patients with skeletal Class II malocclusion treated with bimaxillary orthognathic surgery. Twenty eligible patients treated at our institution from January 2016 to December 2021 with more than 12 months of postoperative follow-up were retrospectively enrolled. Radiographic data of cone-beam computed tomography (CBCT) for each patient were collected at 3 stages: 1 week preoperatively (T0), immediately after surgery (T1), and at least 12 months postoperatively (T2). Positional changes, surface and volumetric alterations of condyle, and bone remodeling in glenoid fossa were measured and compared based on voxel- and surface registrations in visual 3D methods. Most patients exhibited a tendency for condyles to shift posteriorly, laterally, superiorly, and rotated outward, downward, and forward immediately after surgery. Posterior, medial, superior movement and outward, upward, and backward rotation of condyles were observed during follow-up (T1-T2). Bone resorption frequently occurred in the posterior area of condylar surfaces, while bone remodeling was more common in the anterior region of the glenoid fossa. Reduced volume of the condyle was found in most cases, which was not associated with the amount of mandibular advancement. Overall, the condyle and its corresponding glenoid fossa remained relatively stable during the follow-up. Our results reveal positional and morphological alterations in the condyle and the glenoid fossa after bimaxillary orthognathic surgery in patients with skeletal class II malocclusion. These changes predominantly fall within the spectrum of physical adaption.

An automated method for assessing condyle head changes in patients with skeletal class II malocclusion based on CBCT images.

Currently, there is no reliable automated measurement method to study the changes in the condylar process after orthognathic surgery. Therefore, this study proposes an automated method to measure condylar changes in patients with skeletal class II malocclusion following surgical-orthodontic treatment. Cone-beam computed tomography (CBCT) scans from 48 patients were segmented using the nnU-Net network for automated maxillary and mandibular delineation. Regions unaffected by orthognathic surgery were selectively cropped. Automated registration yielded condylar displacement and volume calculations, each repeated three times for precision. Logistic regression and Linear regression were used to analyze the correlation between condylar position changes at different time points. The Dice score for the automated segmentation of the condyle was 0.971. The Intraclass correlation coefficients (ICCs) for all repeated measurements ranged from 0.93 to 1.00. The results of the automated measurement showed that 83.33% of patients exhibited condylar resorption occurring six months or more after surgery. Logistic regression and Linear regression indicated a positive correlation between counterclockwise rotation in the Pitch plane and condylar resorption(p < 0.01). And a positive correlation between the rotational angles in both three planes and changes in the condylar volume at six months after surgery(p ≤ 0.04). This study's automated method for measuring condylar changes shows excellent repeatability. Skeletal class II malocclusion patients may experience condylar resorption after bimaxillary orthognathic surgery, and this is correlated with counterclockwise rotation in the sagittal plane. This study proposes an innovative multi-step registration method based on CBCT, and establishes an automated approach for quantitatively measuring condyle changes post-orthognathic surgery. This method opens up new possibilities for studying condylar morphology.

Effect of tranexamic acid on blood loss reduction in patients undergoing orthognathic surgery under hypotensive anesthesia: a single-center, retrospective, observational study.

Orthognathic surgery is a surgical procedure performed by intraoral approach with established and safe techniques; however, excessive blood loss has been reported in rare cases. In response, investigative efforts to identify methods to reduce the amount of blood loss have been made. Among such methods, the administration of tranexamic acid was reported to reduce the amount of intraoperative blood loss. However, few studies to date have reported the effect of tranexamic acid in orthognathic surgery under hypotensive anesthesia. The present study aimed to investigate the effect of the administration of tranexamic acid on intraoperative blood loss in patients undergoing bimaxillary (maxillary and mandibular) orthognathic surgery under hypotensive anesthesia. A total of 156 patients (mean age, 27.0±10.8 years) who underwent bimaxillary orthognathic surgery under hypotensive anesthesia performed by the same surgeon between June 2013 and February 2022 were included in this study. The following data were collected from the medical records of each patient: background factors (age, sex, and body mass index), use of tranexamic acid, surgical procedures, previous medical history, duration of surgery, American Society of Anesthesiology physical status findings before surgery, intraoperative blood loss as a primary outcome, in-out balance, and blood test results. Descriptive statistics were calculated for statistical analysis, and a t -test and the chi-squared test were used for between-group comparisons. Group comparisons were performed after 1:1 propensity score matching to adjust for confounding factors. Statistical significance was set at P<0.05. Comparison between the groups based on the use of tranexamic acid revealed a significant difference in operation time. Propensity score matching analysis revealed that intraoperative blood loss was significantly lower in the tranexamic acid group. The administration of tranexamic acid was effective in reducing intraoperative blood loss in patients undergoing bimaxillary orthognathic surgery under hypotensive anesthesia.

Postsurgical Volumetric Airway Changes in Class III Patients Receiving Bimaxillary Orthognathic Surgery.

The purpose of the present study was to investigate the pharyngeal airway space (PAS) changes in class III patients receiving bimaxillary orthognathic surgery and correlate the PAS volume and minimum axial section changes with the magnitude of the surgical movement. This research involved a retrospective sample composed of 38 patients with class III skeletal occlusions. Three-dimensional measurements of the PAS volume and minimum axial section were conducted. Cephalometric points were used to verify the extent of jaw-hyoid bone movement. No significant differences were found between pre and postoperative total PAS volume (P = 0.280), nasopharyngeal volume (P = 0.545), oropharyngeal volume (P = 0.297), and minimum axial section (P = 0.568). Anterior movement of point A and posterior nasal spine were significantly associated with an increase in total PAS volume, oropharyngeal volume, and minimum axial section (P < 0.05). However, the posterior movement of menton was significantly associated with a decrease in total PAS volume, oropharyngeal volume, and minimum axial section (P < 0.05). The results of the present study indicated that PAS is not negatively affected by bimaxillary surgery in class III patients. However, the planning of class III patients who are prone to the development of airway problems should be done carefully.

Correlation between oral cavity volume and upper airway changes in skeletal Class III patients undergoing bimaxillary orthognathic surgery: a pilot cone-beam computed tomography study.

To evaluate changes of the upper airway and oral cavity volumes in patients with skeletal Class III malocclusion undergoing bimaxillary orthognathic surgery, and to analyze the correlation between postoperative upper airway decrease and the amount of jaw movement and oral cavity volume reduction. Thirty patients (16 males and 14 females) undergoing bimaxillary surgery were included. Three-dimensional reconstruction of the upper airway and oral cavity were performed using preoperative (T0) and postoperative (T1) (6 months) cone-beam computed tomography scans. The volume, sagittal area and minimum cross-sectional area of the upper airway were diminished (P < .001). The decrease in volume and minimum cross-sectional area in the oropharyngeal region of the upper airway were weakly correlated with B-point posterior movement (P < .05). Total oral cavity volume was decreased, with maxillary oral volume increasing and mandibular oral volume decreasing (P < .001). Upper airway decrease was highly correlated with total oral volume reduction and mandibular oral volume reduction, with the most significant correlation being with total oral volume reduction (P < .001). Class III bimaxillary surgery reduced the volume, sagittal area, and minimum cross-sectional area of the upper airway as well as oral cavity volume. Upper airway changes were weakly correlated with anterior-posterior mandibular movement but significantly correlated with oral cavity volume changes. Thus, oral cavity volume reduction is a crucial factor of upper airway decrease in patients with skeletal Class III malocclusion undergoing bimaxillary orthognathic surgery.

Changes in the upper airway and its surrounding structures after bimaxillary surgery in patients with cleft-related Class III deformity.

To compare upper airway changes following bimaxillary surgery for correction of Class III deformity between patients with unilateral cleft lip and palate (UCLP) and bilateral cleft lip and palate (BCLP) and to compare the preoperative and postoperative upper airway among patients with UCLP and BCLP to healthy controls. Sixty adults with CLP-related skeletal Class III deformity (30 UCLP and 30 BCLP) who consecutively underwent bimaxillary surgery were studied retrospectively. Cone-beam computed tomography (CBCT) was performed before and after surgery to measure upper airway and movements of facial skeletal and surrounding structures. CBCT images from 30 noncleft skeletal Class I adults, matched by age, gender, and body mass index and without surgical intervention, served as controls. After surgery, the volume of the nasopharynx increased in patients with CLP (both P < .001). Patients with CLP did not differ from controls in postoperative volume of the nasopharynx or oropharynx. However, the nasal cavity differed significantly between patients with CLP and controls (P < .001). After bimaxillary surgery, the nasal cavity of patients with CLP differed significantly compared with the controls. Volumes of the nasopharynx and oropharynx did not differ between patients with CLP after surgery and controls.

Enhancing Surgical Outcomes via Three-Dimensional-Assisted Techniques Combined with Orthognathic Treatment: A Case Series Study of Skeletal Class III Malocclusions

(•) Orthognathic surgery is a necessary procedure for the correction of severe skeletal discrepancies, among which are skeletal Class III malocclusions. Currently, both conventional fixed braces and clear aligners can be used in orthognathic surgery. However, the use of clear aligners remains a little-chosen option. The present study aimed to evaluate the skeletal and aesthetic improvements in adults with Class III malocclusion after surgical treatment and compare the results achieved by fixed appliances versus clear aligners. The study sample included four patients (three males and one female, aged 18 to 34 years) with skeletal Class III malocclusion, three of whom underwent a bimaxillary surgery and one of whom underwent only a bilateral sagittal split osteotomy. Two patients were treated with fixed appliances and two with clear aligners. The pre- and post-surgical hard and soft tissue cephalometric measurements were performed and compared for each patient and between fixed appliances and clear aligners. One year after surgery, all patients showed an essential modification of the face’s middle and lower third with an increase in the convexity of the profile and the Wits index and a reduction in the FH^NB angle. No differences were noted between fixed appliances and aligners. Therefore, thanks to the 3D-assisted surgery associated with orthodontics, every participant achieved proper occlusal function and an improved facial aesthetics. In addition, the clear aligners can be considered a valid alternative for pre- and post-surgical orthodontic treatment.

The Association of Body Mass Index and Early Outcomes Following Orthognathic Surgery

The existing data on the link between body mass index (BMI), operative characteristics, and surgical outcomes across orthognathic surgery are limited. The purpose was to measure the association between BMI and early postoperative outcomes in orthognathic surgery. This is a retrospective cohort study of patients (n=118) aged > 14years undergoing bimaxillary orthognathic surgery between 2015 and 2018 by a single surgeon within the Kaiser Permanente Northern California-integrated healthcare system. Patients undergoing unilateral or additional procedures, history of prior orthognathic surgery, or pre-existing pain conditions were excluded. The predictor variable was BMI measured as a continuous (kg/m2) and categorical variable (underweight/normal, overweight, obese). The primary outcome variables were additional postoperative antibiotics, increased postoperative visits, wound dehiscence, and wound infection. The secondary outcome variables were total operative and anesthesia time. The demographic covariates included age, sex, and race/ethnicity. The clinical covariates included history of obstructive sleep apnea, Mallampati score, tobacco use, American Society of Anesthesia classification, thyromental distance, history of difficult intubation, and Angle's classification. Bivariate and multivariate analyses were performed to measure the associations between BMI and the primary and secondary outcomes. Multivariable logistic regression analyses were used to measure associations between BMI and the postoperative outcomes. Statistical significance was defined as P<.05. The study sample was composed of 118 subjects with a mean age of 26.91years (standard deviation 9.43). Forty-seven percent (n=55) were male, and the mean BMI was 25.13 (standard deviation 5.19). BMI category was significantly associated with age, with increasing age associated with higher BMI category (P=.02). According to the bivariate and multivariable logistic regression analyses, controlling for age, race/ethnicity, BMI, and total operative time, increased total operative time was associated with additional postoperative antibiotics (odds ratio=1.03, 95% confidence interval: 1.01, 1.05), and increased postoperative appointments (odds ratio=1.02, 95% confidence interval: 1.01, 1.04). No significant association between BMI and other clinical or operative characteristics was seen aside from American Society of Anesthesia classification. Elevated BMI was not associated with worsened operative characteristics or postoperative outcomes. This supports the suitability of orthognathic surgery in a BMI-diverse population.

Change in taste sensation after orthognathic surgery

ObjectiveThe objective of this study was to evaluate the effect of orthognathic surgery on taste sensation.Materials and methodsThirty-five patients scheduled to undergo Le Fort I osteotomy (LFIO), sagittal split ramus osteotomy (SSRO), and bimaxillary surgery (BMS) were evaluated by administering localized and whole-mouth taste tests preoperatively and postoperatively at months 1, 3, and 6. The patients were asked to identify the quality of four basic tastes applied to six locations on the palate and tongue and to rate the taste intensities they perceived. Taste recognition thresholds and taste intesity scores were evaluted according to operation groups and follow-ups.ResultsThere were significant decreases in the quinine HCl recognition thresholds at the postoperative follow-ups compared to the preoperative in LFIO patients (p = 0.043). There were significant decreases in sucrose taste intensity scores in the right posterolateral part of the tongue at months 3 and 6 compared to preoperative in SSRO patients (p = 0.046), and significant increases in quinine HCL taste intensity scores in the right and left anterior parts of the tongue at month 6 compared to preoperative in LFIO patients (p < 0.05).ConclusionTaste perception is affected due to potential damage to the chemosensory nerves during orthognathic surgical procedures. Generally, non-significant alterations have been observed in taste perception after orthognathic surgery, except for significant alterations in bitter and sweet taste perceptions.Clinical relevanceMaxillofacial surgeons should be aware of taste perception change after orthognathic surgery procedures and patients should be informed accordingly.The trial registration number (TRN)NCT06103422/Date of registration: 10.17.2023 (retrospectively registered).