Mandibular Bilateral Sagittal Split Osteotomy Research Articles

Volumetric evaluation of osteotomy gap following mandibular bilateral sagittal split osteotomy using a novel semi-automated approach: a pilot study

ObjectivesTo establish an analysis pipeline for the volumetric evaluation of the osteotomy site after bilateral sagittal split osteotomy (BSSO).Patients and methodsCone-beam computed tomography (CBCT) was performed before, directly after BSSO, and 6–12 months after surgery. Image segmentations of each osteotomy gap data set were performed manually by four physicians and were compared to a semi-automatic segmentation approach.ResultsFive patients with a total of ten osteotomy gaps were included. The mean interclass correlation coefficient (ICC) of individual patients was 0.782 and the standard deviation 0.080 when using the manual segmentation approach. However, the mean ICC of the evaluation of anatomical sites and time points separately was 0.214, suggesting a large range of deviation within the manual segmentation of each rater. The standard deviation was 0.355, further highlighting the extent of the variation. In contrast, the semi-automatic approach had a mean ICC of 0.491 and a standard deviation of 0.365, which suggests a relatively higher agreement among the operators compared to the manual segmentation approach. Furthermore, the volume of the osteotomy gap in the semi-automatic approach showed the same tendency in every site as the manual segmentation approach, but with less deviation.ConclusionThe semi-automatic approach developed in the present study proved to be valid as a standardised method with high repeatability. Such image analysis methods could help to quantify the progression of bone healing after BSSO and beyond, eventually facilitating the earlier identification of patients with retarded healing.

Accuracy of computer-assisted design and manufactured three-dimensional device for condylar positioning in mandibular bilateral sagittal split osteotomy (clinical trial)

Aligning dental arches in orthognathic treatment after undergoing LeFort I osteotomy or bilateral sagittal split osteotomy (BSSO) relies on occlusal splints, which do not provide precise control over the condylar head. To clinically and radiographically assess the accuracy of computer-assisted design and manufactured (CAD/CAM) surgical guide for condylar positioning in a BSSO. The study recruited 8 patients with a non-syndromic dentofacial deformity who underwent a BSSO. Surgery was planned according to CAD/CAM technology. After osteotomy, a pre-operative guide was used, followed by a repositioning guide. Computed tomography scans were conducted on all patients 1 week pre-operatively, immediately, and 3 months postoperatively. The data are presented as median values with the 25th and 75th percentiles. Eight patients (37.50% females and 62.50% males) between the ages of 19 and 24 underwent BSSOs. The surgical procedure successfully corrected their skeletal deformities. The absolute change between immediate postoperative and pre-operative condylar angle was 0.15 (0.00-0.3). The absolute change between 3 months postoperative and pre-operative condylar angle was 0.20 (0.00-0.30). The stability of the condylar head in position is well assessed by 3-dimensional condylar positioning devices designed and manufactured by CAD/CAM technology in the mandibular BSSO.

Mandibular bilateral sagittal split osteotomy as a treatment approach for upper neck and skull base tumors

The purpose of the study was to present a method for the upper neck and skull base tumor surgery. Bilateral sagittal split osteotomy in the angle area and the traction of the mandibular ramus and body makes it possible to create an additional anatomical corridor for more convenient surgical interventions on the upper neck and the skull base. Case description. At Step 1, intraoral access and mobilization of the angle, ramus, and body of the mandible were performed. At Step 2, bilateral sagittal split osteotomy was performed, followed by anterior traction of the mandible. At Step 3, the upper neck and skull base tumor was accessed. At Step 4, osteosynthesis of the mandibula was performed. Results. The proposed approach reduces surgical trauma, minimizes the risks of intraoperative complications, and increases the chances of complete tumor resection in the skull base tumors. The presented technique is based on our experience of the deep neck and skull base tumor surgery. Conclusion. The method of mandibular bilateral sagittal split osteotomy in the surgery of upper neck and skull base tumors increases the rate of complete resections, reduces the surgical trauma, and minimizes the risks of intraoperative complications. The presented method provides fast postoperative rehabilitation and an optimal cosmetic result. В статье представлена методика операции по удалению образований верхней трети шеи и основания черепа c созданием дополнительного анатомического коридора путем межкортикальной остеотомии в области угла и отведения ветви и тела нижней челюсти (НЧ). Клинический случай. Пациент H., 38 лет поступил в КЦ ЧЛХиС с жалобами на припухлость в подчелюстной области, затруднение при глотании. По данным КТ-ангиографии было выявлено объемное образование верхней трети шеи. На первом этапе проведен внутриротовой доступ и поэтапная мобилизация угла, ветви и тела НЧ. На втором этапе выполнена межкортикальная остеотомия с последующим отведением НЧ кпереди. На третьем этапе проведена коллотомия и выполнен доступ к опухоли и основанию черепа. На четвертом этапе проведен остеосинтез НЧ и ушивание ран. Результаты. Представленная методика доступа к образованиям основания черепа позволяет уменьшить операционную травму, минимизировать риски интраоперационных осложнений, увеличить радикальность основного этапа операции. Описанная методика основана на серии клинических наблюдений удаления глубинно расположенных образований боковой поверхности шеи, а также основания черепа. Заключение. Таким образом, применение метода межкортикальной остеотомии в хирургии опухолей основания черепа позволяет увеличить радикальность основного этапа операции, уменьшить операционную травму, а также минимизировать риски интраоперационных осложнений. Представленный метод обеспечивает быструю реабилитацию пациентов после операции и обладает косметическим эффектом.

Effect of modified bilateral sagittal split osteotomy on inferior alveolar nerve neurosensory disturbance

The aim of this study was to assess the occurrence of neurosensory disturbance of the inferior alveolar nerve (IAN) following modified mandibular bilateral sagittal split osteotomy (BSSO) that preserves the mandibular inferior border. All patients undergoing BSSO, associated or not with a Le Fort I osteotomy (performed by the same senior operator) between January 2018 and December 2019, were eligible. The modified BSSO consists of a modification of the technique described by Epker: the bony section of the buccal cortex stops 3-4 mm above the basal mandibular edge. While respecting the basilar border, sectioning is then performed up to the gonial angle where bicortical section is finally performed. Sensibility of the labial and chin area was evaluated immediately postoperatively, and at six months and two years of follow up. A total of 140 eligible patients underwent the modified BSSO between January 2018 and December 2019, and 72 were included. Hypoaesthesia was found in 81.9% of the patients (59/72 patients) at initial evaluation. It decreased to 45.8% (33/72 patients) at the six-month examination and to 12.5% (9/72 patients) at the last examination. Four bad splits were recorded. The modified BSSO preserves the inferior border of the mandible and maintains the IAN in the lingual fragment. There is no need to release the IAN, hence its manipulation is reduced and the incidence of IAN postoperative hypoaesthesia is also reduced.

Changes and Remodeling of Intersegmental Interferences following Bilateral Sagittal Split Ramus Osteotomy in Patients with Mandibular Prognathism

Purpose: This study aimed to measure the amount of change in the mandibular angle, intergonial width, and ramus angulation due to intersegmental interference and changes in condyle position after mandibular bilateral sagittal split ramus osteotomy (BSSRO) in patients with mandibular prognathism and to evaluate the correlation between them. Materials and Methods: A total of 32 patients who underwent mandibular setback using the BSSRO of the mandible to manage skeletal prognathism during the years 2018 to 2020 at the Department of Oral and Maxillofacial Surgery, Pusan National University were followed both clinically and with cone beam computed tomography (CBCT) for at least one year. Those who were also treated with genioplasty or other orthognathic surgery were excluded from the study. The mandibular angle (gonial angle: Ar–Go–Me), intergonial width (Go–Go), and total angle (sum of left and right proximal segmental angle) were recorded. Changes in the ramus were compared and analyzed before surgery (T1), immediately after surgery (T2), and one year following surgery (T3). Results: The mandibular angle increased by an average of 0.14 degrees immediately after surgery (T2–T1) and increased by 0.97 degrees at 12 months postoperatively (T3–T2). No correlation was observed with the amount of change in each group relative to the amount of mandibular setback. The mandibular width decreased by 0.01 mm on average immediately after surgery (T2–T1), and by 4.2 mm on average at 12 months after surgery (T3–T2). The angle of the mesial fragment of the mandible increased by 1.04 degrees immediately after surgery (T2–T1), compared to the preoperative state. It decreased by 0.86 degrees at 12 months postoperatively (T3–T2). Conclusion: The increase in the mandibular angle from immediately after surgery to 12 months after BSSRO reflects the counterclockwise rotational tendency to prevent opening restriction when intentionally selecting the condylar position. The decrease in the intergonial width immediately after surgery is thought to be due to the effect of internal trimming to minimize the bone interference between the outer surface of the distal bone fragment and the inner surface of the mesial fragment, and the decrease 1 year after surgery can be considered to be due to bone remodeling. Interosseous interference during mandibular setback osteotomy does not necessarily cause an increase in the width of the mandibular angle after surgery.

Improved lip esthetics in patients with skeletal Class III malocclusion and facial asymmetry after isolated mandibular orthognathic surgery

Asymmetry of the lips severely affects facial esthetics and is often one of the chief complaints of orthognathic patients, especially those with Class III malocclusion. The objectives of this study were to investigate the changes in lip symmetry in patients with mandibular prognathism and deviation and the relationships between jaw hard tissue and lip soft-tissue changes. Three-dimensional facial scan and cone-beam computed tomography scan data of 30 orthodontic-orthognathic patients treated with bilateral sagittal split ramus osteotomy were combined to conduct the research. Paired-sample t test and Pearson correlation coefficient were applied to compare the differences in the same variable before and after the orthognathic surgery and the potential correlations between the changes in hard and soft variables. To explore the important hard tissue variables influencing the lip soft-tissue changes, linear regression analysis was performed. Although there was significant upper lip asymmetry presurgery, the upper lip asymmetry was corrected postsurgery. Surgical correction of the mandibular deviation was also accompanied by lengthening of the bilateral philtrum crests. Improvement in lip asymmetry and lengthening of the philtrum crests were primarily related to the transverse correction of the mandible rather than sagittal changes. The corresponding prediction formulas were established. The isolated mandibular bilateral sagittal split ramus osteotomy surgery can substantially improve the upper and lower lip asymmetry in patients with mandibular prognathism and deviation, but one should be wary of the unesthetic effects associated with lengthening of the philtrum crests.

Early Orthosurgical Treatment of a Skeletal Class III: Can the Self-Esteem Be Improved?

Young patients with a skeletal Class III malocclusion with a strong psychological and appearance impact may require surgical correction during their growth. This case report describes the orthosurgical treatment of a 11-year-old boy with history of bullying, presenting severe Class III skeletal malocclusion, anterior cross-bite and mandibular prognathism. He also had significant vertical and anteroposterior discrepancies and a concave profile with prominent lips. The treatment plan included extraction of the first premolars, a maxillary LeFort I osteotomy and a mandibular bilateral sagittal split osteotomy. The orthodontic treatment combined with the two-jaw surgery improved his jaws alignment, occlusal function, and the most important: his self-esteem and quality of life.

Virtual Surgical Planning Combined With Intraoperative Navigation in Mandibular Bilateral Sagittal Split Osteotomy for Accurate Placement of Patient Specific Implants.

The aim of the study is to evaluate clinical methods to obtain a significantly improved fitting of patient specific implants (PSI) in bilateral sagittal split osteotomies and to evaluate the use of electromagnetic navigation as a potential guide for condyle positioning. A prospective study using (1) a solid bite registration index during preoperative computed tomography, (2) critical planning with regard to the condylar rotation, (3) a piezoelectric saw throughout the mandibular osteotomy, and (4) intraoperative navigation to determine the position of the PSIs and the mandibular segments intraoperatively was performed. Ten patients were treated. Five underwent bilateral sagittal split osteotomies and 5 bimaxillary osteotomy. All of the PSIs fitted precisely onto the mandible and the screws into the predrilled screw holes. The predetermined occlusion was obtained. A precise fitting of the PSIs in the lower jaw seems to be possible to achieve with above-mentioned methods. The intraoperative navigation system gives a possibility to verify the surgical outcome during surgery but is not accurate enough to be used as a virtual drill guide alone.

Severity and long-term complications of surgical site infections after orthognathic surgery: a retrospective study

Surgical site infections (SSI) occur in 1.4% to 33.4% of cases after orthognathic surgery. This type of complication is a major concern to surgical teams, but there is no consensus for the prevention and treatment of SSI in orthognathic surgery. The purpose of this descriptive study was to evaluate the severity and the consequences of postoperative infections. The charts of all the patients operated on by the orthognathic surgery team between January 2015 and July 2017 were collected. All types of orthognathic procedures (Le Fort I maxillary osteotomy, bilateral sagittal split mandibular osteotomy, and genioplasty) were screened, and patients diagnosed with SSI were included. Demographic data, timing and severity of the infection, as well as long-term complications were recorded. Five hundred and twelve patients were screened. Forty-one patients (8%) presenting with SSI were included. There were 18 men and 23 women. The site of the infection was mandibular for 38 patients (92.7%) and maxillary for 3 patients (7.3%). The average time between surgery and infection was 31.5 days. Twenty-four patients received isolated oral antibiotics for inflammatory cellulitic reaction (58.8%), 15 patients had a localized collection treated by incision and drainage under local anesthesia (36.6%), and 2 patients had an extensive collection requiring surgical drainage under general anesthesia (4.9%). Five patients (12.2%) needed hardware removal for plate loosening, and 2 patients (4.9%) developed chronic osteomyelitis. Infection following orthognathic surgery is easily treated most of the time with no long-term complications. In cases of patients with potential risk factors for severe infection, antibiotics may be given with curative intents.

The relationship between neurosensory disturbance of the inferior alveolar nerve and the lingual split pattern after sagittal split osteotomy

The aim of this study was to evaluate the relationship between neurosensory disturbance (NSD) and the different types of bilateral sagittal split osteotomy (BSSO) lingual fracture created. The study group consisted of 45 patients with mandibular deformities (90 sides; 14 males and 31 females). Computed tomography (CT) scans were obtained preoperatively and 1 week postoperatively. All patients were divided into lingual fracture line groups on the basis of their postoperative scans. NSD was tested preoperatively and 1, 3, and 12 months postoperatively by using a sensory touch Semmes-Weinstein (SW) test and the 2-point discrimination (TPD) test. Patients were divided into 2 groups on the basis of their lingual fracture lines after mandibular BSSO; among the 45 patients, 39 sides (43.3%) had short-splits, and 51 sides (56.7%) had long-splits. The short-split group was less affected at all tested times, and the difference between the 2 groups was significant 1 month postoperatively on TPD test but not at other times on the both tests. The split type did not affect the NSD incidence at 3 and 12 months postoperatively.

Craniofacial Deformities in Patients With Beta-Thalassemia: Orthodontic Versus Surgical Correction-A Systematic Review.

Rapid blood cell turnover and bone marrow expansion caused by beta-thalassemia (βT) result in craniofacial and dentoalveolar anomalies. This report presents a systematic review of the literature over the past 50 years on orthodontic and surgical considerations in the management of βT-affected patients. Seventeen publications encompassed 24 patients, 11 male individuals and 13 female individuals, 7 to 43 years of age. Eleven patients underwent only surgical treatment, eleven combined orthodontic-surgical treatment, and 2 orthodontic treatment. Surgical treatment primarily addressed typical maxillary overgrowth by maxillary reshaping, premaxillary segmental repositioning, or complete Le Fort I impaction and set back osteotomy. In severe maxilla-mandibular discrepancy and/or increased lower facial height, a bilateral sagittal split mandibular osteotomy is the treatment of choice. Although surgery involves risks of excessive bleeding, morbidity, and impaired nasal esthetics, little attention is given to the orthodontic modality. In conclusion, the current literature recommends early interceptive orthodontics aimed to decrease dentoskeletal deformities, severe malocclusion, and soft tissue imbalance. Treatment includes maxillo-mandibular orthopedic and functional manipulation with dentoalveolar treatment, which might either prevent orthosurgical procedures later or reduce its extent. This suggested a multidisciplinary approach comprising a hematologist, a pediatrician, a pediatric dentist, and an orthodontist, which might also significantly improve the patient's quality of life.

A Modified Novel Technique for Condylar Positioning in Mandibular Bilateral Sagittal Split Osteotomy Using Computer-Assisted Designed and Computer-Assisted Manufactured Surgical Guides

Current techniques for orthognathic surgery after Le Fort I osteotomy and bilateral sagittal split osteotomy (BSSO) rely on intermediate and final occlusal splints for proper positioning of the dental arches without any control in positioning the condyle and ramus segments. Setting the 2 condyles in centric relation in the glenoid fossae at fixation is paramount for condylar function and the accuracy and stability of postoperative occlusion. Usually the 2 ramus segments are manually positioned and fixated in the final position according to the surgeon's experience. This report describes a novel technique to position the condyle and ramus segments in centric relation using skeletal guides designed by computer-assisted designed and computer-assisted manufactured (CAD-CAM) technology. The skeletal guides have a double-U shape designed to be tooth borne on the distal segment and bone borne on the proximal segment. The guides fit on the last molar crown and the anterior border of the ramus; using these reference points will position the mandibular arch and 2 ramus segments in ideal centric occlusion and centric relation. The condyle position in the sagittal, horizontal, and transverse planes was analyzed by computed tomography and differences in measurements were calculated. This technique confirms precise control of the condylar segment in centric relation with stable centric occlusion using CAD-CAM guides during BSSO.

No differences in infections between patient-specific implants and conventional mini-plates in mandibular bilateral sagittal split osteotomy — Up to 3-year follow-up

The use of individually designed osteotomies, combined with individually manufactured osteosynthesis material, is rapidly becoming a standard for more challenging maxillofacial surgery. The benefits of patient-specific implants (PSI) in orthognathic surgery are clear in complex cases. PSIs can enhance precision and ease up the surgical protocol. We previously reported on the benefits of PSIs as reposition and fixation systems during Le Fort I osteotomy. The aim of this study was to evaluate a cohort of 28 patients, treated with bilateral sagittal split osteotomy (BSSO) and PSIs for fixation, with regard to healing for up to 3 years. A retrospective cohort of 48 patients with conventional mini-plate repositioned mandibles was also collected for statistical analysis. No statistically significant differences were found with regard to infection, soft tissue problems, or reoperations between these two groups.

Dental occlusal-surface-supported titanium guide to assist cutting and drilling in mandibular bilateral sagittal split osteotomy.

Cutting and drilling guides manufactured using computer-aided design/computer-aided manufacturing (CAD/CAM) technologies have attracted increasing interest in orthognathic surgery, particularly in complex cases. The development of these guides requires virtual surgery planning and three-dimensional modelling before they can be printed in titanium, polyamide or resin. We report the use of a personalized titanium device to assist bilateral sagittal split osteotomy (BSSO) with or without genioplasty combined with individual implants for repositioning and fixation. This one-piece guide for both sides of the BSSO allows the initiation of cutting and drilling with less invasive drill placement and greater accuracy. The titanium guide was manufactured using CAD/CAM technologies after conventional digital planning of BSSO. Intraoperatively, the guide was fitted on each side of the mandibular occlusal surface and screwed to predesigned drill holes. The guide facilitates the predrilling of screw holes and the initiation of cutting for buccal, lingual and external oblique ridge corticotomy using a piezosurgery device. Based on our experience, we think that this guide is a promising new tool to assist BSSO. It helped limit the extent of tissue detachment required and provided the strength necessary for accurate bone cutting and drilling. It also allowed the accurate fixation of preformed plates to obtain occlusion as per virtual planning.

Management of Skeletal Class III Malocclusion due to Mandibular Prognathism Coexisting with Vertical Maxillary Excess

This case report describes combined orthodontic and orthognathic management of skeletal Class III malocclusion in a female patient presenting with prognathic mandible, increased maxillary height, severe hyperdivergence, gummy smile, and upper anterior proclination. Presurgical orthodontics involved extraction of maxillary first premolars and decompensating the proclined upper incisors. Orthognathic surgery involving differential maxillary impaction, mandibular bilateral sagittal split osteotomy setback, and sliding genioplasty. Postsurgical orthodontics was initiated one month after the surgery to finish the case in Class II molar relationship and Class I canine relationship with proper intercuspation. The outcome had acceptable results with good esthetics and occlusion.

Bilateral sagittal split mandibular osteotomies for enhanced exposure of the anterior cervical spine in children: technical note.

The bilateral sagittal split mandibular osteotomy (BSSMO), a common maxillofacial technique for expanding the oropharynx during treatment of micrognathia, is a rarely employed but useful adjunct to improve surgical access to the ventral cervical spine in children. Specifically, it provides enhanced exposure of the craniocervical junction in the context of midface hypoplasia, and of the subaxial cervical spine in children with severe kyphosis. The authors describe their technique for BSSMO and evaluate long-term outcomes in patients. The pediatric neurosurgical database at a single center was queried to identify children who underwent BSSMO as an adjunct to cervical spine surgery over a 22-year study period (1993-2015). The authors retrospectively reviewed clinical and radiographic data in all patients. The authors identified 5 children (mean age 5.3 ± 3.1 years, range 2.1-10.0 years) who underwent BSSMO during cervical spine surgery. The mean clinical follow-up was 3.0 ± 1.9 years. In 4 children, BSSMO was used to increase the size of the oropharynx and facilitate transoral resection of the odontoid and anterior decompression of the craniocervical junction. In 1 patient with subaxial kyphosis and chin-on-chest deformity, BSSMO was used to elevate the chin, improve anterior exposure of the subaxial cervical spine, and facilitate cervical corpectomy. Careful attention to neurovascular structures, including the inferior alveolar nerve, lingual nerve, and mental branch of the inferior alveolar artery, as well as minimizing tongue manipulation and compression, are critical to complication avoidance. The BSSMO is a rarely used but extremely versatile technique that significantly enhances anterior exposure of the craniocervical junction and subaxial cervical spine in children in whom adequate visualization of critical structures is not otherwise possible.

Mandibular advancement for patients with obstructive sleep apnoea syndrome: a comparison of bilateral mandibular distraction osteogenesis and bilateral sagittal split osteotomy

Mandibular advancement for patients with obstructive sleep apnoea syndrome: a comparison of bilateral mandibular distraction osteogenesis and bilateral sagittal split osteotomy

Prevalence of Surgical Site Infections Following Orthognathic Surgery: A Double-Blind, Randomized Controlled Trial on a 3-Day Versus 1-Day Postoperative Antibiotic Regimen

The purpose of this study was to determine the effect of a 3- versus 1-day antibiotic regimen on the rate of surgical site infection (SSI) in patients undergoing orthognathic surgery at a department of oral and maxillofacial surgery in Halifax, Nova Scotia, Canada. A prospective, randomized controlled trial was conducted. All patients received 1day of intravenous antibiotics after surgery. Then, patients were randomly distributed into groups that received 2days of additional antibiotics (group A) or placebo (group B). The primary outcome measured was the presence of SSI. The operating surgeon, concomitant extraction of teeth, surgical procedures performed, duration of intermaxillary fixation, and length of hospital stay were analyzed for an effect on SSI. Patients were followed for 1year after surgery to identify SSIs that might have been diagnosed outside the hospital. The trial started with 288 patients, and 117 patients were lost to follow-up. Statistical analyses were ultimately performed on those 171 patients who were adherent to the study medication regimen. Group A (n= 86) and B (n= 85) SSI rates were 7.0 and 17.6% (number needed to treat= 10; P= .04), respectively. Mandibular bilateral sagittal split osteotomy (BSSO) was involved in 71% of SSIs. Intra- and postoperative surgical variables did not have a relevant effect on the SSI rate. Patients were followed for 1year after surgery, and group A (n= 46) and group B (n= 44) had SSI rates of 4 and 25% (P < .05), respectively. Three days of postoperative cefazolin and cephalexin markedly decreases SSI rates compared with 1day. However, the number needed to treat of 10 suggests that the benefits of the extended regimen might not outweigh the risks. The high prevalence of SSIs at the mandibular BSSO incisions might have been caused by contamination, with more saliva and reception of a lower blood supply, than maxillary Le Fort I incisions. Mandibular osteotomies could benefit from an extended antibiotic regimen to minimize SSIs and associated complications. Other surgical variables might not require special consideration for antibiotic therapy.

Influence of temporomandibular joint disc displacement on mandibular advancement in patients without pre-treatment condylar resorption

The purpose of this study was to clarify the correlation between pre-treatment anterior disc displacement and mandibular stability after orthognathic and orthodontic treatment among patients with a skeletal class II malocclusion and without pre-treatment condylar resorption. Thirty-seven patients were included (7 male, 30 female). The mean length of follow-up was 6.76±3.06 years. Patients with condylar resorption before treatment were excluded. Magnetic resonance images and lateral cephalometric radiographs were taken before treatment (T0), after treatment (T1), and at follow-up (T2). Patients were classified according to the degree of disc displacement: −10–10° ‘normal’, 11–50° ‘slight to mild’, ≥51° ‘moderate to severe’. Results showed the condyle moved posterosuperiorly after treatment, and then moved anteriorly to a more concentric location during the long follow-up period. Condylar movement was found not to correlate with disc displacement. The degree of disc displacement before treatment did not correlate with the post-surgical mandibular positional change in either the sagittal or vertical direction. To conclude, the mandibular bilateral sagittal split ramus osteotomy was stable in the long-term after orthognathic and orthodontic treatment. In the absence of pre-treatment condylar resorption, the degree of initial anterior disc displacement did not have a significant influence on the stability of mandibular advancement.

“Converting a bi-jaw surgery to a single-jaw surgery:” Posterior maxillary dentoalveolar intrusion with microimplants to avoid the need of a maxillary surgery in the surgical management of skeletal Class III vertical malocclusion

The management of a vertical skeletal Class III malocclusion with mandibular prognathism revolves around the protocol of bi-jaw surgery (maxillary LeFort I impaction and mandibular bilateral sagittal split osteotomy with setback). The maxillary surgery not only provides increased stability to the ultimate surgical outcome but also increases the amount by which the mandibular set back can be done, therefore aiding in greater profile improvement. With the need of maxillary surgery almost inevitable in treating such situations, the complexity and the increased discomfort associated with such surgery can never be ignored. Is it at all possible to convert a bi-jaw surgery into a single-jaw surgery with the aid of microimplants? With increasing number of patients being treated with microimplants for anterior openbite and gummy smiles, our idea was to incorporate this novel protocol in treating Class III vertical situations and therefore avoid the need of a maxillary surgery in treating such a situation, together with achieving optimum treatment outcome.