Bimaxillary Surgery Research Articles

An overview of treatment strategies for class II and class III malocclusions

Class II and class III malocclusions represent common yet complex dental conditions that affect both aesthetics and function. Managing these malocclusions requires an approach tailored to the patient's growth stage, with early interventions focusing on growth modification and adult cases often necessitating surgical solutions. In class II malocclusions, growth modification with functional appliances such as the Twin Block and Herbst appliance promotes mandibular advancement and improves facial harmony in younger patients. For older individuals or those with more severe malocclusions, orthodontic camouflage or mandibular advancement surgery, including bilateral sagittal split osteotomy, is recommended to achieve a balanced occlusal relationship and improve facial proportions. Class III malocclusions, often involving a prognathic mandible or maxillary deficiency, are particularly challenging. For young patients, facemask therapy and rapid maxillary expansion can encourage maxillary growth, while chin cup therapy can control mandibular projection, aiming to improve skeletal balance. In severe adult cases, combined orthodontic-surgical treatments, such as maxillary advancement through Le Fort I osteotomy or mandibular setback procedures, provide durable, functionally stable outcomes. Surgical-orthodontic approaches, including bimaxillary surgery, are particularly advantageous for severe class III cases by effectively addressing the underlying skeletal imbalances and enhancing facial aesthetics. Growth modification techniques emphasize the importance of early diagnosis and intervention, aiming to harness natural growth potential and reduce the need for more invasive treatments later in life. For adult patients, surgical interventions present a definitive solution, delivering substantial improvements in function and appearance. Ongoing advances in both orthodontic and surgical techniques are refining the precision and stability of treatment outcomes, underscoring the need for individualized, age-appropriate strategies in managing class II and class III malocclusions.

Sagittal Discrepancies of Intraoperative Results between 2D and 3D Planning in Orthognathic Surgery: A Series of 44 Cases

Pre-surgical planning in orthognathic surgery is a process of vital importance for obtaining satisfactory results for both the clinician and the patient. There are different planning methods, among which 3D software is one of the most important. These allow precise observation of the movements of bone and soft tissue structures, which until recently could not be predicted. Despite its advantages, many specialists continue to plan using the 2D method. The aim of this paper is to present the discrepancies between 2D and 3D preoperative planning and the intraoperative results of 44 patients undergoing bimaxillary orthognathic surgery and, together with this, to expose the variables that possibly influence the occurrence of these differences.

Angled Screws With Locking Plates-An Alternative Fixation for Minimally Invasive Mandibular Orthognathic Surgery.

The purpose of this study was to evaluate the short-term behavior of angled screws with locking plates after bilateral sagittal split osteotomy using the anterior oblique technique within the concept of minimally invasive orthognathic surgery (MIOS). Twenty patients who underwent bimaxillary surgery with mandibular advancement were included in this preliminary and retrospective study. All patients underwent computed tomography preoperatively and 1 day postoperatively. The incidence of neurosensory dysfunction, clinical evaluation of the occlusion and temporomandibular joint, and overall complications were recorded during a minimum follow-up of 4 months. The mean extent of sagittal mandibular advancement movements was 7.2mm (2.5-13.2mm). All patients had stable occlusion without evidence of temporomandibular joint dysfunction. None of the patients presented with dysaesthesia, hyperaesthesia, or anesthesia after four months of follow-up. The overall results of this study are very satisfactory with no major or minor complications. The new design of mandibular plates with locking screws can be an alternative in all orthognathic surgeries, but especially interesting for minimally invasive approaches where stronger fixation is needed. Long-term studies are needed to draw further conclusions.

Evaluating Surgical Accuracy in Bimaxillary Surgery: A Systematic Review and Meta-Analysis of Mandible-First versus Maxilla-First Approaches.

Mandible-first surgery (MdFS) has gained attention as an alternative to the traditional maxilla-first surgery (MxFS) in bimaxillary procedures. Given the distinct sequence of operations between these approaches, evaluating the clinical advantages of MdFS compared to MxFS is crucial for optimizing surgical decision-making. This systematic review and meta-analysis examine intraoperative achievability and postoperative stability between these two surgical approaches. A thorough literature search was performed using PubMed, Embase, Web of Science, and MEDLINE, covering articles published from 2013 to 2023. Studies included were retrospective, prospective, and randomized trials that compared the accuracy and/or stability of MdFS with MxFS. The primary endpoint for the meta-analysis was the standardized mean difference in surgical accuracy for translational movements, with a secondary focus on rotational accuracy. A total of 11 studies encompassing 712 patients met the inclusion criteria. The analysis suggested that MdFS might reduce accuracy in the sagittal dimension (CI, 0.05 to 0.74) but offered greater achievability in the vertical direction (CI, - 0.47 to - 0.07). Additionally, MdFS was associated with a relatively posterior (CI, - 1.18 to - 0.60) and inferior (CI, - 0.64 to - 0.07) positioning of the maxillomandibular complex. Despite certain limitations, our findings indicate that MdFS can achieve clinical outcomes similar to MxFS in terms of both accuracy and stability. However, further researches with larger sample sizes and more rigorous study designs are necessary to validate these conclusions. 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 .

Screening of Sensorial and Inflammatory Changes in Patients Submitted to Orthognathic Surgery.

Despite the high levels of success after orthognathic surgery, the immediate postoperative pain and edema, besides the neurosensorial deficits, are common complications. This study aimed to evaluate the pattern of sensory and inflammatory responses in patients undergoing orthognathic surgery. This prospective observational study included 20 patients undergoing bimaxillary orthognathic surgery, who were evaluated in the preoperative period and on Days 1, 2, 3, 4, 5, 6, 7, and 30 after surgery, using a battery of tests to assess sensorial and inflammatory changes. Subjective and objective evaluations of edema indicated a trend toward edema resolution within 30 days, with a significant decrease in mouth opening on days 1, 7, and 30 after surgery. Regarding nasal obstruction, a significant increase in Nasal Obstruction Symptom Evaluation (NOSE) scores was demonstrated on the first, second, and third days, returning to preoperative levels after 30 days. There was a significant increase in visual analogic scale (VAS) scores from the first to the seventh day after surgery, with a reduction within 30 days. For mechanical and thermal sensitivity tests, the lower lip and chin regions had poorer results, without recovery after 30 days. Positive correlations were observed between painful and inflammatory parameters, as well as between subjective and objective evaluations. Analysis of saliva biomarkers did not show significant differences for pre- and postoperative CCL3 or CCL4 levels. Data provide new evidence about the early inflammatory and sensorial complications after orthognathic surgery.

Is minimally invasive approach to genioplasty predictable for mentolabial soft tissue? A retrospective cohort study

IntroductionThe aim of this study was to conduct a three-dimensional analysis of the effects on mentolabial soft tissues of three different orthognathic surgery protocols: bimaxillary surgery without genioplasty, bimaxillary surgery with conventional or minimally invasive genioplasty (MIS). Materials and methodsPre-operative and post-operative CBCT were superimposed to quantify and ascertain the direction of mandibular movements, and soft tissue were analyzed to evaluate the hard to soft tissue ratio. Data from 97 consecutive patients were evaluated: 30 conventional genioplasty, 36 MIS and 31 no genioplasty. ResultsThe impact of the surgical movements on the overlying soft tissues can be consider with stronger correlation in the group No Genioplasty in the whole mentolabial region, stronger correlation in labial and pogonion region in the MIS group and no stronger correlation in the conventional group. ConclusionsSutures in the mentolabial region directly interfere with the postoperative impact of orthognathic surgery on soft tissues in mentolabial area, in both the vertical and horizontal directions. A smaller incision – consequently involving less detachment of soft tissues in the region – may promote a lower risk of chin ptosis, in addition to greater suspension of the musculature.

Effect of maxillary advancement on velopharyngeal function in cleft lip and palate: 20 years of experience

This retrospective study aimed to investigate the impact of orthognathic surgery with maxillary advancement (MA) on the velopharyngeal function (VF) in individuals with cleft lip and palate (CLP).The study included 651 patients with repaired CLP, both sexes, aged over 18 years who underwent MA alone or in combination with nasal procedures and/or mandibular osteotomy, operated between 2000 and 2019. The main outcome measures were nasalance (nasal text-NT and oral text-OT) and velopharyngeal orifice area measurement (VA), determined by nasometry and pressure-flow technique, respectively.Preoperatively, mean nasalance scores for NT and OT indicated normality, and VA demonstrated borderline-inadequate velopharyngeal closure in all patients. Following MA, a significant increase in nasalance scores for NT and OT occurred (p < 0.001), revealing hypernasality in those undergoing MA combined with nasal procedure (MAN, N = 191), bimaxillary orthognathic surgery with nasal procedure (BON, N = 227) and bimaxillary orthognathic surgery (BO, N = 151). Conversely, nasalance scores remained within the normal range for those undergoing isolated maxillary advancement (IMA, N = 82). VA exhibited a significant increase leading to the classification of VF as inadequate in the BON and MAN groups. Overall, MA contributed to VF deterioration, resulting in the appearance of hypernasality and increased VA, particularly when combined with nasal procedures.

Three-dimensional Analysis of Skeletal Stability in Cleft Lip and Palate Patients Undergoing Bimaxillary Surgery With Le Fort I Osteotomy and Intraoral Vertical Ramus Osteotomy.

Orthognathic surgery in patients with lip and palate clefts is challenging owing to scar tissue from primary repairs and severe deformities. In this study, we evaluated the stability of Le Fort I osteotomy with intraoral vertical ramus osteotomy (IVRO) in patients with cleft lip and palate using 3-dimensional (3D) analysis. This retrospective study comprised 14 cleft lip and palate patients (3 females, 11 males; the average age at surgery: 23.8y) who underwent bimaxillary orthognathic surgery involving Lefort I osteotomy and IVRO. Cone-beam computed tomography (CBCT) images were obtained at preoperative (T0), 1-month postoperative (T1), and 1-year follow-up (T2) periods. The 3D analysis assessed the transitions and rotations of the maxilla and mandible using a virtual triangle. The maxilla showed stability in all directions at the 1-year follow-up with minimal relapse. The distal segment of the mandible exhibited clinically acceptable anterior (1.15mm relapse) movements and pitch rotation (2.88° counterclockwise relapse) during the first year postoperatively. The proximal mandibular segment underwent anterior-inferior transition (1.21 and 2.01mm, respectively) and lateral-outward rotation (4.90° and 7.51°, respectively) postsurgery, remaining unchanged 1 year postoperation. Le Fort I osteotomy with IVRO provides skeletal stability in patients with cleft lips and palates. This study demonstrated a minimal maxillary relapse and clinically acceptable movements in the distal mandibular segment during the first postoperative year. The proximal mandibular segment moved anteriorly and inferiorly, rotated laterally and outward after surgery, and remained unchanged at the 1-year follow-up.

The Use of Bone Substitute Blocks in Minimally Invasive Orthognathic Surgery: Enhancing Jaw Stability and Healing.

This study aims to evaluate the use of bone substitute blocks (BSBs) in minimally invasive orthognathic surgery for the maxilla, mandible, and chin, highlighting their impact on jaw stability and bone healing. A retrospective analysis was conducted on 47 consecutive patients (33 females, 14 males; mean age: 27y) who underwent bimaxillary advancement surgery. Procedures employed the minimally invasive orthognathic surgery approach. Bovine BSBs (Bio-Oss Collagen) were used to fill gaps in all cases. Postoperative follow-up included computed tomography scans at immediate and 1-year intervals. All patients achieved the desired clinical outcomes without complications such as wound dehiscence, infection, or nonunion. Visual Analog Scale scores indicated high levels of bone formation, with mean scores of 9.1 in the chin, 8.5 in the maxilla, and 7.9 in the mandible. The study supports the routine use of BSBs in orthognathic surgeries, though further research is needed to validate these findings and explore long-term outcomes.

Comparative analysis of 3D tomography based soft tissue rendering and Proface facial scanning systems in orthognathic surgery

PurposeThis study aimed to investigate the linear and angular differences in the nasolabial soft tissue in patients who underwent bimaxillary orthognathic surgery using two different three-dimensional imaging methods. Furthermore, the advantages, disadvantages, and limitations of these methods were determined after comparing the data obtained from the imaging methods used in the study. Materials and MethodsPreoperative (T0) and 6-months postoperative (T1) cone-beam computed tomography (CBCT) and three-dimensional facial scanning (3DFS) data from 22 patients who underwent maxillary advancement surgery were examined. The DICOM (Digital Imaging and Communications in Medicine) data (CBCT group) and “.obj” format images (3DFS group) of the patients were analyzed using Dolphin software (Dolphin Imaging®, Version 12, Chatsworth, CA, USA). The linear and angular soft tissue measurements were calculated after determining the reference anatomical landmarks for both groups. ResultsMeasurements with CBCT and 3DFS imaging methods were compared at T0, T1, and all measurements (T0+T1). No statistically significant difference was observed between the CBCT and 3DFS groups for five measurements performed at T0 and T0+T1, but statistically significant differences were observed between the groups for the other seven measurements. There was no statistically significant difference between the CBCT and 3DFS groups for six measurements at T1, but there were statistically significant differences between the groups for the other six measurements. After reviewing the postoperative differences in the nasolabial soft tissue, a statistically significant increase in four linear and one angular measurement in the 3DFS group was observed, and there was a statistically significant increase in two linear and two angular measurements in the CBCT group. Upon comparison of postoperative differences in soft tissue alterations, no statistically significant difference between the 3DFS group and the CBCT group were observed in any of the soft tissue measurements. ConclusionOrthognathic surgery has significant effects on nose width and upper lip morphology. Although both 3DFS and CBCT methods can be used to evaluate such effects, the results of the present study revealed differences in sensitivity and limitations between the two methods. Thus, surgical outcomes should be evaluated in consideration of the abovementioned parameters.

Virtual surgical planning in orthognathic surgery: A prospective evaluation of postoperative accuracy

ObjectivesThe development of 3D computer-assisted technologies over the past years has led to vast improvements in orthognathic surgery. The aim of the present study was to evaluate differences in maxillary position between 3D virtual surgical planning (VSP) and surgical results. Materials and methodsWe assessed data from 25 patients who underwent bimaxillary non-segmented orthognathic surgery with 3D VSP. Each patient underwent a postoperative CT scan within 40 days after surgery. We compared the STL (Standard Triangulation Language) file from the VSP with that obtained from the postoperative CT. ResultsAccording to our comparative analysis, the postoperative and VSP 3D models did not statistically differ. The Lin concordance correlation coefficient was always >0.95 for each landmark, but in 21 patients (84 % of the sample) we identified at least one point with a difference of more than 1.5 mm between the postoperative and VSP 3D model on at least one axis. The most frequently observed differences corresponded to sagittal translation and pitch rotation. ConclusionsAn intraoperative clinical and aesthetic evaluation of the consequences of bone movements on patient face is strongly recommended, also when we use VSP because we may have clinically significant differences from the planning.

Facial asymmetry outcome of orthognathic surgery in mild craniofacial microsomia compared to non-syndromic class II asymmetry

ObjectivesTo compare the facial asymmetry after bimaxillary surgery between mild craniofacial microsomia (CFM) and non-syndromic class II asymmetry.Materials and methodsCone-beam computed tomography scans of adults with Pruzansky-Kaban types I and IIA CFM (CFM groups, n = 20), non-syndromic skeletal class II asymmetry (Class II group, n = 20), and normal controls (control group, n = 20) were compared. The area asymmetry of lower face and jaw bones was quantified. Landmark-based method was used to evaluate the lower facial asymmetry regarding midline, cants, and contour.ResultsThere were no significant postoperative differences in the hemi-facial and hemi-jaw area asymmetry between CFM and Class II groups, both of which were significantly larger than the control group. No significant difference was found in the midline deviation and lip and occlusal cants between CFM and Class II groups. The vertical contour asymmetry in CFM group became significantly larger than Class II group. Compared to the control group, the deviation of pronasale, subnasale, and soft-tissue menton, lip and occlusal cants, and sagittal and vertical contour asymmetry in CFM group were significantly larger, as were the deviation of subnasale and soft-tissue menton and vertical contour asymmetry in Class II group.ConclusionsThe vertical contour asymmetry of mild CFM was significantly larger than non-CFM class II after surgery, while the area asymmetry, midline deviation, cants, and sagittal contour asymmetry of lower face showed no significant difference.Clinical relevanceBe aware that correcting vertical asymmetry of contour, lip, and dentition in CFM is still challenging.

Psychological status of patients with skeletal Class III malocclusion undergoing bimaxillary surgery: A comparative study.

Skeletal Class III malocclusion can significantly impact psychological well-being. Although bimaxillary surgery is a well-established corrective intervention, its psychological effects are not fully understood. This study aims to investigate changes in self-esteem, sensitivity to criticism, and social appearance anxiety following surgery to inform targeted nursing interventions for psychological adaptation. This comparative study included 205 participants: 150 patients with skeletal Class III malocclusion who underwent bimaxillary surgery, and a control group of 55 individuals without malocclusion. The malocclusion group had a mean age of 21.99 ± 2.28 years (96 males, 109 females). The control group consisted of department interns with Class I occlusion, normal overjet and overbite, and typical facial appearance, with a mean age of 21.61 ± 2.40 years (26 males, 29 females). Psychological assessments, validated for reliability, measured self-esteem, sensitivity to criticism, and social appearance anxiety before and after surgery. Statistical analyses, including independent sample t tests and one-way ANOVA, were performed to compare outcomes between the groups, with a significance level set at P < .05. Preoperative assessments revealed that patients with skeletal Class III malocclusion had significantly lower self-esteem and higher sensitivity to criticism and social appearance anxiety compared to the control group (P < .05). Postoperatively, there were modest improvements in self-esteem and significant reductions in sensitivity to criticism and social appearance anxiety, though levels of social appearance anxiety remained higher than those in the control group (P < .05). No significant differences in self-esteem and sensitivity to criticism were observed between the surgical and control groups postoperatively (P > .05). Within-group comparisons showed significant improvements in all measures after surgery (P < .05). Bimaxillary surgery positively affects the psychological well-being of patients with skeletal Class III malocclusion, enhancing self-esteem and reducing sensitivity to criticism and social appearance anxiety. However, some psychological concerns persist, indicating a need for targeted nursing interventions to further support these patients' psychological well-being.

Evaluation of Minimum Axial Airway Area and Airway Volume in Orthognathic Surgery Patients.

The aim of this study was to compare preoperative and postoperative linear, planar, and volumetric measurements in the pharyngeal airway in orthognathic surgery patients. Preoperative and postoperative cone beam computed tomography (CBCT) images of 60 patients, who underwent maxillary advancement with mandibular setback (Group I, n=25) and bimaxillary advancement (Group II, n=35), were compared. The airway was divided into 3 regions as nasopharynx, oropharynx, and hypopharynx. Linear and planar measurements were made on the reference sections of each region. The minimum axial airway area, the volume of 3 regions, and total airway volume were also measured. Regarding the linear, planar, and volumetric measurements, while there was a statistically significant increase in the measurements for all three regions in Group II, in Group I only the measurements in the nasopharyngeal region demonstrated a statistically significant increase postoperatively ( P <0.05). There was an increase in minimum axial airway areas in both groups; however, it was only statistically significant in Group II ( P <0.05). There was a statistically significant increase in total airway volumes in both groups ( P <0.05). A positive and good correlation was found between the percent increase in the minimum axial area and the percent increase in the total volume ( P <0.05). While bimaxillary advancement surgery results in a significant increase in the pharyngeal airway, mandibular setback with maxillary advancement caused an increase in the total airway. Changes that may occur in the airway should be considered while planning orthognathic surgery.

The Assessment of Upper Airway Volume Changes Following Bimaxillary Advancement Surgery: A Radiological Evaluation in the Supine Position at Multiple Intervals.

Background: Bimaxillary surgeries (BiMax) are an essential part of the craniomaxillofacial specialty. The osteotomies and subsequent spatial rearrangement of the maxilla and the mandible enable the correction of facial deformities, asymmetry, and malocclusion. Moreover, the movements performed during the procedure affect the morphology of surrounding soft tissues, including the upper airway (UA). Objectives: The objective of this study was to radiologically assess the potential volumetric alterations of the UA in the supine position at various intervals following BiMax advancement surgeries. Methods: A group of 31 patients who underwent BiMax advancement surgery were included in the study. Medical computed tomography (CT) of the head and neck region was performed 2 weeks preoperatively, 1 day postoperatively, and 6 months postoperatively. The UA volumes were calculated and analyzed based on the acquired Digital Imaging and Communications in Medicine (DICOM) files using different software applications. The sella-nasion-A point (SNA) and sella-nasion-B point (SNB) angles were evaluated to measure the achieved maxillomandibular advancement. Results: When comparing the volume of the UA before surgery, post-surgery, and 6 months post-surgery, the p-value was <0.001, indicating statistically significant differences in UA volume between the successive examinations. A statistically significant difference was found between UA volume before surgery and 6 months post-surgery and between UA volume after surgery and 6 months post-surgery, with the obtained p-values being <0.001 and 0.001, respectively. A significantly larger UA volume was observed 6 months post-surgery (mean ± SD: 27.3 ± 7.3) compared to the volume before surgery (mean ± SD: 22.2 ± 6.4), as well as 6 months post-surgery compared to the volume assessed shortly after surgery (mean ± SD: 24.2 ± 7.3). Conclusions: BiMax advancement surgeries result in the significant enlargement of the UA. The volume of the UA does not diminish immediately following the procedure and is not constant; it increases significantly during the postoperative observation period.

Comprehensive analysis of alar base inclination and lip line cant following orthognathic correction of maxillomandibular asymmetry: A retrospective study

This paper examines the relationship between roll rotation of the jaws and changes in alar base or lip line asymmetry in the coronal plane following orthognathic correction. The study involved patients with preoperative frontal alar base and lip line asymmetries greater than 0.5° (because it corresponds to the minimum asymmetry perception threshold) and underwent bimaxillary orthognathic surgery without (Group I) or with (Group II) genioplasty. The alar base angle (ABA), lip line cant angle (LLCA), maxillary cant angle (MxCA), and mandibular cant angle (MnCA) were measured using preoperative and 12 months postoperative cone beam computed tomography (CBCT) images. Thirty-four patients were included in the study. Significant correlations were found between changes in MxCA and ABA besides between changes in MnCA and LCA in Groups I (P = 0.016, P˂0.001, respectively) and II (P = 0.002, P˂0.001, respectively). The mean of the change in ABA/the change in MxCA and the change in LLCA/the change in MnCA ratios for Group I were 0.59 ± 1.57 and 0.73 ± 0.94, respectively, while those for Group II were 0.46 ± 3.70 and 0.39 ± 2.00, respectively. Angular measurements from jugular and mental foramina points, aligned with the bony midline, offer a convenient tool for predicting alar base and lip symmetry during bimaxillary orthognathic surgery planning.

Assessing the Risks and Benefits of Hypotensive Anesthesia and Piezosurgical Instruments in Bimaxillary Surgery.

The challenge in bimaxillary surgery lies in significant intraoperative bleeding, prompting various strategies to minimize blood loss. Among the methods considered for controlling intraoperative bleeding, hypotensive anesthesia and the use of piezosurgical instruments (Osada, Tokyo, Japan) have been explored. However, hypotensive anesthesia may have adverse effects on cardiac function, and surgical time is likely to be prolonged when using piezosurgical instruments. This study retrospectively examined whether the combined use of hypotensive anesthesia and piezosurgical instruments reduces intraoperative bleeding and whether the combination impacts cardiac function. The combination of hypotensive anesthesia and piezosurgical instruments significantly reduced intraoperative bleeding. Furthermore, the combination was associated with a significantly higher incidence of tachycardia, particularly with the use of nicardipine. Additionally, the combination significantly lengthened the duration of the surgery and may have increased the burden on cardiac function. Landiolol was effectively employed to manage tachycardia. When selecting hypotensive anesthesia as a means to limit bleeding, proactive preparation and preventive small-dose administration of landiolol could be beneficial in managing the potential occurrence of tachycardia.

Does surgical sequencing influence the accuracy of maxillary positioning in bimaxillary cleft orthognathic surgery?

To evaluate whether the sequence of osteotomies influences the accuracy of maxillary positioning in patients with cleft palate ± cleft lip undergoing bimaxillary orthognathic surgery (OGS). This was a prospective study of patients with Veau 2-4 clefts who underwent bimaxillary OGS at tertiary-care children's hospital over a 3-year period. The primary predictor variable was the sequence of osteotomies (maxilla-first versus mandible-first). The primary outcome of interest was the concordance between the planned and achieved maxillary position, as assessed using linear and angular measurements. Secondary study predictors were demographic and surgical variables. Differences between groups were compared using non-parametric independent samples tests for continuous measures (data reported as median and interquartile range, IQR) and chi-squared tests for categorical measures. For all analyses, p≤ 0.05 was considered significant. Subjects who underwent maxilla-first (n=15) and mandible-first (n=16) operations were comparable with regard to age, gender, cleft type, skeletal classification, segmental maxillary osteotomy, and magnitude of maxillary movement (p ≥ 0.09). The planned sagittal and vertical positions of the maxilla were similarly accurate between the two groups (p ≥ 0.68). Angular accuracy was also comparable (p ≥ 0.56) between the study groups. In patients with CP ± CL undergoing bimaxillary orthognathic surgery, use of mandible-first sequencing, when compared to maxilla-first sequencing, does not impact accuracy of maxillary positioning in the immediate post-operative period in well-selected patients.

The Incidence of Obstructive Sleep Apnea in Patients with Dento-Skeletal Malformation.

Purpose: The aim of this article is to analyze the incidence of undiagnosed obstructive sleep apnea (OSA) in patients affected by dento-skeletal malformation. We also evaluated the patterns most affected by the condition and calculated the post surgical changes. Methods: We conducted a retrospective cohort study on 71 patients including 35 men and 36 women. The patients studied were affected by dento-skeletal class II and III malformations and underwent bimaxillary orthognathic surgery in all cases. Patients were evaluated with polysomnography before surgery and at least 6 months after surgery to assess any improvement or worsening of the apnea hypopnea index (AHI) index. Regarding AHI evaluation criteria, an AHI > 5 was considered indicative of OSA, 4 < AHI < 5 was considered borderline and AHI < 4 was considered indicative of non-OSA. We also considered demographic variables like age at the time of intervention and gender, and anatomical variables like the pattern of the dento-skeletal deformity and the presence or absence of maxillary hypoplasia. Qualitative variables were described as absolute and relative frequencies, while quantitative variables were summarized as mean and standard deviation. To quantitatively express the relationship between two variables, the correlation coefficient was calculated. The covariance array was used to evaluate multiple correlations. Results: Our study shows that there is a significant percentage (33%) of patients who undergo orthognathic surgery with an AHI > 5 and also a percentage of patients (11%) who can be considered to be "borderline." It emerges that the pattern most at risk is the one characterized by retruded maxilla and patients with dento-skeletal class II. Considering the post surgical period, the statistical analysis shows that after surgery, only 8% of malformed patients present an AHI > 5, compared to the 20.5% described in the Italian population. Conclusions: In patients who receive orthognathic surgery, the presence of obstructive sleep apnea is significantly higher than in the general population. When planning the surgical correction of a dento-skeletal malformation, the surgeon must aim not only for the esthetics results, but also for proper stomatognathic and respiratory function; this cannot be achieved without taking polysomnography information into account.

Evaluation of mandibular condyle position in Class III patients after bimaxillary orthognathic surgery: A cone-beam computed tomography study.

This retrospective study evaluated the mandibular condyle position before and after bimaxillary orthognathic surgery performed with the mandibular condyle positioned manually in patients with mandibular prognathism using cone-beam computed tomography. Overall, 88 mandibular condyles from 44 adult patients (20 female and 24 male) diagnosed with mandibular prognathism due to skeletal Class III malocclusion who underwent bilateral sagittal split ramus osteotomy (BSSRO) and Le Fort I performed using the manual condyle positioning method were included. Cone-beam computed tomography images obtained 1-2 weeks before (T0) and approximately 6 months after (T1) surgery were analyzed in three planes using 3D Slicer software. Statistical significance was set at P < 0.05 level. Significant inward rotation of the left mandibular condyle and significant outward rotation of the right mandibular condyle were observed in the axial and coronal planes (P < 0.05). The positions of the right and left condyles in the sagittal plane and the distance between the most medial points of the condyles in the coronal plane did not differ significantly (P > 0.05). While the change in the sagittal plane can be maintained as before surgery with manual positioning during the BSSRO procedure, significant inward and outward rotation was observed in the axial and coronal planes, respectively, even in the absence of concomitant temporomandibular joint disorder before or after the operation. Further long-term studies are needed to correlate these findings with possible clinical consequences.