Sagittal Split Osteotomy Research Articles

Secondary Reconstruction of Panfacial Fractures With Virtual Reality Surgical Planning Using Both Pre and Postreconstruction Scans.

Late secondary reconstruction is sometimes required in patients with suboptimal primary panfacial fracture repair. At this stage, it can be difficult to discern original facial architecture due to malunion and bony remodeling. By utilizing the original postinjury CT scan to complete fracture reduction in the virtual reality (VR) planning environment, the surgeon may attempt to recreate an "ideal" facial bony anatomy for patients. This technique was completed in 2 patients presenting with facial deformity secondary to malunited panfacial fracture. Each had a cone-beam CT (CBCT) scan taken at presentation and the initial postinjury CT scans were obtained. Fracture reductions were completed in VR to recreate the preinjury anatomy. The resulting model was overlaid with current anatomy to create surgical aids. The first patient, a 23-year-old man, presented with malunion of all bones of the midface. Cutting guides were designed for the Lefort 1 segment, left zygomaticomaxillary complex (ZMC), and naso-orbito-ethmoid (NOE) osteotomies. The second patient, a 30-year-old woman, had bilateral ZMC and subcondylar fractures, midface retrusion, and malunion of parasymphyseal fracture. A 2-stage procedure was planned, including an initial Lefort I and bilateral sagittal split osteotomy with midline wedge excision. To address malar projection, a second surgery was planned using custom MEDPOR midface implants for the NOE and zygomatic regions. Both patients were discharged home, and all surgical goals and esthetic objectives were achieved.

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.

Three-Dimensional Mandibular Condyle Remodeling Post-Orthognathic Surgery: A Systematic Review

Background and Objectives: The most popular surgical procedures among orthognathic surgeries for Class II and III patients are Le Fort 1 osteotomy for the maxilla and bilateral sagittal split ramus osteotomy (BSSRO) for the mandible. Keeping the condyle in its proper place during fixation is one of the difficulties of orthognathic surgery. One of the worst post-orthognathic surgery consequences in the temporomandibular joint (TMJ) area may be condylar resorption. Condylar remodeling refers to a group of processes that occur in reaction to forces and stress placed on the temporomandibular joint in order to preserve morphological, functional, and occlusal balance. A systematic review of the literature was performed with the aim of identifying the mandibular condylar component of TMJ changes after orthognathic surgery in class II and III patients. Materials and Methods: An electronic search was carried out using the PubMed, Cochrane Library, and Google Scholar, databases. The inclusion criteria included trials in non-growing patients upon whom orthognathic surgery was performed due to Angle II or Angle III classes malocclusion; in addition, a CT or cone beam computed tomography (CBCT) scan was performed before and after surgery to track the mandibular condylar component of TMJ changes. The quality of the studies was evaluated by two independent authors. The risk of bias was assessed by using the Downs and Black checklist. Results: The electronic and manual literature search yielded 12 studies that fulfilled all necessary inclusion criteria. Observed studies were evaluated as good (3), fair (8), and poor (1) quality. Two studies evaluated class II patients, six studies observed class III patients, and four studies were comparative. Most of the studies evaluated condyle angle and space changes, and the condylar surface and volume changes were also observed. However, the methodology of evaluation in the publications differs. Conclusions: Reduction of bone density, especially in class II patients, and morphological condyle reshaping, with the apposition of the bone, is the main adaptive mechanism after orthognathic surgery. However, all of the studies we examined were conducted using different methods of evaluation, measurement, and reference points.

Influence of the Inferior Turbinate on the Accuracy of Superior Maxillary Repositioning.

Notably, many studies have focused on the bony interference in the maxillary segment when performing maxillary superior repositioning; however, few reports have described the interference with the inferior nasal turbinate. Therefore, the authors aimed to retrospectively analyze the soft tissue or bone tissue volume of the inferior nasal turbinate and the accuracy of maxillary superior repositioning in Le Fort I osteotomy (LF1). The authors included 83 patients with facial deformities who underwent conventional LF1 (maxillary molar elevation between 4.0 and 6.0mm) with/without bilateral sagittal split ramus osteotomy. The ratio of the soft tissue of the inferior turbinate to that of the inferior nasal cavity was used to divide the participants into 2 subgroups (large and small ratio). Similarly, the bony tissue volume of the inferior turbinate was used to divide the participants into 2 subgroups (large and small bony tissues), and the planned or actual amount of superior repositioning was compared 3 dimensionally. In the soft tissue group, the subgroups showed no significant differences (P=0.934). However, the actual maxillary superior repositioning was significantly lower in the large bone group than in the planned maxillary elevation group (P<0.01). In cases where the maxillary molar needs to be elevated by >4mm and the bone tissue of the inferior nasal turbinate is well developed, an adjunctive technique such as horseshoe osteotomy or partial inferior turbinate resection should be considered in addition to LF1 to avoid interference between the inferior nasal turbinate and the maxillary bone fragments.

The Stress Effects of Mandibular Movements on the Temporomandibular Joint With Sagittal Split Ramus Osteotomy.

The aim of this study was to evaluate the stress changes in the temporomandibular joint (TMJ) after sagittal split ramus osteotomy (SSRO) with finite element analysis (FEA). 5 and 10mm mandibular setback and advancement were applied to models by using SSRO and a control model without osteotomy evaluated. The articular disc was modeled as superelastic, and the stresses on the articular fossa, disc, and condyle were evaluated. The stresses on the cartilage were 1.150 MPa on the 5mm advancement model and 1.506 MPa on the 10mm advancement model. The stresses on the disc were 11.56 MPa on the 5mm advancement model, 7.94 MPa on the 10mm advancement model and the amount were significantly higher than other models. The stress, especially in the cartilage, increased with the amount of advancement. In the setback models, the stresses on the condylar cartilage and the disc were higher than in the control model, and the stress in the condylar cartilage increased with the amount of setback. SSRO increases the stresses in the TMJ components and stresses increase depending on the amount of advancement and setback and may cause the development of joint problems.

Assessment of biomechanical strength of titanium versus unsintered-hydroxyapatite/poly-L-lactic acid (u-HA/PLLA) osteosynthesis screws in bilateral sagittal split ramus osteotomy

Titanium osteosynthesis is considered to be stable for the bilateral sagittal split ramus osteotomy (BSSRO) procedure in orthognathic surgery but is disregarded owing to a multitude of complications, the most significant necessitating a secondary surgery for removal. Bioresorbable osteofixation devices, especially third-generation unsintered-hydroxyapatite/poly-L-lactic acid (u-HA/PLLA), are increasingly used in the mandibular region because of their strength and bioactive/osteoconductivity. To date, three titanium bicortical screws has been the standard for the rigid fixation of BSSRO. As data on the use of u-HA/PLLA bicortical screws are limited, we conducted an in vitro biomechanical strength test to evaluate the performance of 12-mm bicortical u-HA/PLLA screws in comparison with titanium screws using mandibular bone models. BSSRO was performed on all specimens, followed by fixation with either three titanium screws or three, four, or five u-HA/PLLA screws, and loading was performed using a clinically presumed occlusal force. Displacement forces (measured in newton ‘N’) of 50N, 130N, and 220N were applied. Our results showed that the use of three u-HA/PLLA screws was unstable, that of four u-HA/PLLA screws was comparable, and that of five u-HA/PLLA screws provided stability equal to that of the three titanium bicortical screws. Although further clinical assessment is needed, our study demonstrated that the five u-HA/PLLA bicortical screws are viable alternatives to titanium in BSSRO osteofixation.

Clinical evaluation of greater palatine artery hemodynamics in Le Fort I osteotomy

ObjectiveLe Fort I osteotomy (LIO) is a widely known standard orthognathic surgical treatment. However, complications such as osteonecrosis of the jaw due to poor postoperative blood flow to tissues of the maxilla have been reported. This study measured the hemodynamics of the greater palatine artery (GPA) in patients who underwent LIO to explore the factors that affect postoperative blood flow. MethodsWe included 15 patients who underwent LIO and sagittal split ramus osteotomy (SSRO), and 8 patients, who only underwent SSRO, were included as controls. Preoperative, intraoperative, and postoperative blood flow in the oral mucosa anterior to the foramen magnum was measured with a laser Doppler blood flow meter. ResultsOn average blood flow at immediately after downfracture in LIO patients reduced to 24.8% of baseline blood flow and patients who underwent anterior maxillary movement had a lower recovery rate at any time. Multiple regression analysis showed that the greater the maxillary anterior shift and the longer the time from maxillary disarticulation to fixation (mandibular fracture time: DFT), the more delayed was the blood flow recovery. ConclusionsSince blood flow decreased after downfracture and recovered only to around 85.4% of baseline after 6 months in LⅠO, preserving blood vessels is important. Furthermore, the recovery rate was lower in patients who underwent anterior movement, and blood flow reduced more in patients with longer DFT, suggesting the importance of determining the direction and distance of movement preoperatively, and repositioning and fixing the maxilla as quickly as possible during surgery.

Effect of transcutaneous electrical nerve stimulation on maximum mouth opening after orthognathic surgery: A randomised controlled trial

Background: The present study aims to determine the effect of transcutaneous electrical nerve stimulation (TENS) on maximum mouth opening (MMO) after orthognathic surgery. Materials and Methods: This study is a randomised clinical trial. The samples of this study were class III patients who are candidates for Le Fort I osteotomy surgery for maxillary advancement and bilateral sagittal split osteotomy (BSSO) for mandibular setback surgery due to the lack of maxilla growth and mandibular prognathism using the Dalpont method. On the day following surgery, the intervention group received TENS physiotherapy and instructions to take analgesics. In the control group, patients only received analgesics. MMO was measured in both groups using a digital caliper preoperatively, one month, and six months postoperatively. Results: A total of 82 patients participated in this study, who were divided into two groups of 41, intervention and control. The difference in the mean MMO in different periods after surgery of the intervention group (F=59733.350, P&lt;0.001) and the control group (F=32.480, P&lt;0.001) was significant. The pattern of MMO increase over time was not the same in the 2 groups. There was a steeper slope in the increase of MMO in the intervention group than in the control group. Conclusion: It can be concluded from the results of this study, that the use of TENS after orthognathic surgery can be effective along with analgesics in reducing pain intensity and, subsequently, recovery in MMO in the short term.

Does the modified inferior border osteotomy improve the surgical outcomes in bilateral sagittal split osteotomy?

BackgroundTo investigate the effect of lower border osteotomy on the lingual split pattern and IAN in BSSO procedures. Materials and MethodsThe study comprised 32 patients (64 operated sides) who underwent bilateral sagittal split osteotomy (BSSO) due to dentofacial abnormalities between the periods of April 2021 and April 2022. In the mandible, 32 sides (the conventional group) received standard BSSO surgery, while 32 sides (the modified group) additionally received lower border osteotomy. Data regarding the split difficulty of the mandibular in BSSO surgery and the recovery status of the inferior alveolar nerve (IAN) one year after surgery were obtained and evaluated from patient records. The fracture line was radiographically evaluated for the lingual split pattern following surgery. ResultsA statistically significant difference was observed in favor of the modified group when the mandibular split difficulty of the groups was compared (p=0.032). The split time of the modified group was found to be statistically shorter than the conventional group (p≤0.001). The mean numbness level of the modified group one year after surgery was statistically significantly lower than that of the conventional group (p = 0.019). Although there was no statistically significant difference between the two groups in terms of lingual fracture pattern, the rate of type 1 (87.5%) fracture was higher in the modified group compared to the other group (68.8%) (p=0.089). ConclusionThe lower border osteotomy performed in addition to the conventional BSSO surgery allows the split procedure easier and in a shorter time. The modification resulted in an increased incidence of type 1 lingual fracture pattern in the mandible. The neurosensory recovery capacity of the IAN in the postoperative period is higher in areas where lower-border osteotomies are performed.

Orthodontic-Orthognathic Management of a Patient With Severe Mandibular Deficiency Due to Bicondylar Fracture: A Case Report

This case report is about a 30-year-old Iranian female. The patient’s chief complaint was the backwardness of the lower jaw. The patient reported a history of condylar fractures in childhood. There was crowding in the maxillary and mandibular arch, and the midline in the mandible was 2 mm deviated to the left. The canine and first premolar on the left side of the maxilla were extracted, and the canine on the left side of the mandible was impacted. Clinical examinations and paraclinical documents revealed that the patient was a skeletal class II case with mandibular deficiency, complicated by a vertical maxillary excess. Virtual surgery planning was used to plan the patient’s treatment. The amount of adhesion of soft tissue to hard tissue was also taken into consideration. According to the measurements of the patient and the class II, vertical maxillary excess of the patient, the shortness of the ramus, and the large angle of the occlusal plane, our chosen orthognathic surgery included bilateral sagittal split osteotomy, advancement genioplasty, and maxillary impaction.

Changes in mandibular width and frontal-lower facial profile after orthognathic surgery using sagittal split ramus osteotomy with removal of internal bone interference in patients with class III skeletal malocclusion

BackgroundThe purpose of this study is to analyze changes in mandibular width and frontal view ramus inclination using cone beam CT in patients with skeletal class III malocclusion who underwent BSSRO, with the removal of bone interference between segments. MethodsFor all 20 subjects, cone-beam CT imaging was performed prior to surgery (T1), immediately post-surgery (T2), and 6 months after surgery (T3). Reorientation was performed using R2GATE software (MegaGen, Seoul, Korea). The gonion and antegonial notch were used as reference points in the sagittal view, and the most lateral point of the condyle head was used as the reference point in the frontal view. All measurements were recorded in the frontal view.ResultsInter-gonial width decreased by 2.64 mm at T3-T2 (P < .001) and by 2.58 mm at T3-T1 (P < .05). Inter-antegonial width decreased by 1.75 mm at T3-T2 (P < .05) and by 3.5 mm at T3-T1 (P < .001). In the frontal view, the right ramus inclination based on the gonion increased by 2.07° at T3-T1 (P < .05). The left ramus inclination based on gonion increased by 2.45° at T2-T1 (P < .05) and by 3.94° at T3-T1 (P < .001). The right ramus inclination based on antegonial notch increased by 2.35° at T2-T1 (P < .05) and by 3.04° at T3-T1 (P < .01). The left ramus inclination based on antegonial notch increased by 2.73° at T2-T1 (P < .001) and by 3.18° at T3-T1 (P < .001).ConclusionsDuring bilateral sagittal split osteotomy, removing bone interference between the proximal and distal segments results in a reduction of postoperative mandibular width and an increase in frontal view ramus inclination.

Impact of the orofacial muscular rehabilitation exercise on facial expression recovery post-orthognathic surgery

ObjectiveThis study aimed to evaluate the impact of myofunctional rehabilitation of the orofacial muscles through specific exercises on the recovery of facial expression in patients following orthognathic surgery. Material and MethodsThe study included 62 patients who underwent Le Fort I and sagittal split ramus osteotomy (SSRO). Patients were divided into two groups: the first group started immediate post-operative myofunctional rehabilitation of the orofacial muscles through specific exercises. In contrast, patients in Group II did not undergo any myofunctional rehabilitation post-operative exercises. The recovery of facial expressions postoperatively was evaluated in both calm and smiling states by comparing the differences between 3D facial scanning data of chosen facial anatomical structures collected at five key time points: pre-surgery (D0), 2 days (D2), 14 days (D14), 1 month (D30), and 3 months (D90) postoperatively. ResultsThe analysis revealed that characteristic angles and lengths experienced significant changes post-surgery, with ∠chRnchL and ∠chRsnchL decreasing at D2 and normalizing by D30 in the experimental group, while the control group showed a slower recovery, normalizing by D90. The ChL-R length decreased at D2, returning to normal by D30 in the experimental group and D90 in the control group. The height Li-Ls increased at D2 and normalized by D30 in calm and smiling expressions across single and double jaw surgery patients. These findings underscore the more rapid recovery in the experimental group compared to the control group (P < 0.05; P < 0.005; P < 0.0001). ConclusionInitiating myofunctional rehabilitation immediately following orthognathic surgery enhances facial muscle function recovery, improves patient confidence, and expedites social reintegration. This approach is crucial for functional and psychological benefits.

Effectiveness of tranexamic acid on intra- and postoperative bleeding in Bimaxillary osteotomies: a retrospective study.

Perioperative bleeding is a serious concern during orthognathic surgery. Tranexamic acid (TXA), a synthetic lysine analog with antifibrinolytic properties, reduces blood loss across various surgical fields. This study aimed to investigate the effectiveness of preoperative TXA administration in reducing intraoperative and postoperative blood loss following combined Le Fort I and sagittal split ramus osteotomies at our hospital. This single-center, retrospective cohort study included patients who underwent combined Le Fort I and sagittal split ramus osteotomies between November 2017 and October 2022. The primary outcome was the volume of intraoperative blood loss. Among 1,329 eligible patients, 87 were included in the analysis (32 in the TXA group and 55 in the control group, where no TXA was administered). The median (interquartile range) intraoperative blood loss was 200.0 (157.5-237.5) mL in the TXA group and 260.0 (180.0-350.0) mL in the control group, showing a significant difference between the groups (p = 0.0365). However, postoperative blood drainage within 24h and 24-48h did not differ significantly between the two groups. A single intravenous administration of TXA was associated with a decrease in intraoperative bleeding without severe adverse events during combined Le Fort I and sagittal split ramus osteotomies. However, postoperative blood loss, nausea, vomiting, and autologous blood transfusion were not significantly associated with this administration.

Does mandible ramus height asymmetry affect postoperative skeletal stability in orthognathic surgery patients?

BackgroundRelapses following orthognathic surgery have been reported to exceed 2% to 50%, depending on multiple factors. This study aimed to analyze the stability after orthognathic surgery in patients with mandibular ramus height asymmetry through 3D reconstruction using Cone-beam CT.MethodsThis retrospective cohort study investigated patients who underwent mandibular setback surgery using bilateral sagittal split ramus osteotomy. Three-dimensional CT scans were taken at three different time points. Evaluation of the postoperative stability involved measuring changes in the x, y, and z axes as well as roll and yaw rotations of the mandible at specific landmarks (B point, mental foramen) on 3D CT scans obtained immediately after surgery and 6–12 months postoperatively. They were categorized into four groups based on bilateral mandibular height asymmetry through Asymmetry index (AI). The one-way ANOVA was implemented to compare the intergroup differences and Tukey's post hoc test was employed. Additionally, the Pearson correlation coefficient was also calculated.ResultsA total of 24 patients were included in this study. The corresponding AI, representing the degree of asymmetry in both mandibles, were calculated as Group 1 was 1.25 ± 0.64%, Group 2 was 2.89 ± 0.47%, Group 3 was 5.03 ± 0.51%, and Group 4 was 9.40 ± 1.99%. The x-axis change in Group 4 was significantly larger at 1.71 mm compared to Group 1 at 0.64 mm. The mandibular roll, Group 4 showed a statistically significant increase at 1.33° compared to Group 1 at 0.35°. And there was a significant positive correlation observed between x-axis change and AI (p = 0.019), as well as between mandibular roll and AI (p = 0.025).ConclusionAfter orthognathic surgery, stability was influenced by numerous factors, with the findings of this study suggesting that the degree of ramus height asymmetry in the mandible can be considered one contributing factor.

A simple and free software-based inferior alveolar nerve protector surgical guide in bilateral sagittal split osteotomy

ObjectivesThis technical note introduces a novel concept of a alveolar inferior nerve protector guide during orthognathic surgery based on a free-software creation and printing. Technical NoteOrthognathic surgery using Virtual Surgical Planning software like Dolphin Imaging ® v 11.9 facilitated a bimaxillary procedure with mandible advancement and occlusal plane correction, later followed by 3D printing of splints. The process involved importing a composite skull with osteotomies into Blender ® software, where solids were added and edited to match Dolphin's osteotomies, ensuring bone contact without distortion. The guide creation was performed adhering to bilateral sagittal split osteotomy principles, maintaining precision, resulting in preserved inferior alveolar nerve and faster operation times compared to non-guided procedures, as demonstrated by postoperative CT scans. ConclusionsIntegrating advanced tools like Blender software into maxillofacial surgery represents a significant advancement. Despite challenges like the absence of specific manuals for this purpose in Blender, using such software offers innovative and cost-effective solutions. Developing user-friendly resources tailored to surgical applications such as a protector guide within Blender can enhance its usability and improve surgical outcomes and patient care, leading to groundbreaking advancements in maxillofacial surgery.

Factors predicting neurosensory disturbance after bilateral sagittal split ramus osteotomy: a retrospective cohort study

Neurosensory disturbances (NSD) are the most widely recognized complication of bilateral sagittal split ramus osteotomy (BSSRO), but predictors of NSD remain unclear. The aim of this study was to identify factors predicting NSD following BSSRO. A retrospective cohort study of 129 consecutive patients with dentofacial deformities (median age 24.0 years; 76.0% female), who underwent BSSRO (95 without genioplasty, 34 with genioplasty), was conducted. The presence of NSD was evaluated at 6 months postoperatively and was found in 97 patients (absent in 32 patients). Potential NSD-related factors investigated were age, sex, genioplasty, mandibular canal type, inferior alveolar nerve (IAN) exposure, mandibular movement, and laterality. Multivariate binary logistic regression analysis was conducted to elucidate factors predicting NSD, with calculation of odds ratios (OR) and 95% confidence intervals (CI). The dependent variable was defined as NSD after BSSRO. Independent variables were those with P < 0.100 in the univariate analysis. In the multivariate binary logistic regression analysis, NSD showed a significant association with BSSRO with genioplasty (adjusted OR 3.87, 95% CI 1.21–12.26; P = 0.022) and left IAN exposure (adjusted OR 4.69, 95% CI 1.49–14.73; P = 0.008). The study findings may lead to enhanced clinical outcomes for BSSRO.

Positions of the Mandibular Foramen and Canal in Different Skeletal Classes and Implications for Bilateral Sagittal Split Osteotomy.

To evaluate the positions of the mandibular foramen (MF) and mandibular canal (MC) between different skeletal classes to highlight the implications for bilateral sagittal split osteotomy (BSSO). A cross-sectional study was performed using cone-beam computed tomography on 90 patients classified into classes I, II and III. Linear measurements were performed on multiplanar reconstructions as follows: from the MF to the edge of the mandibular ramus (1), to the mandibular notch (2), to the ramus width (3) and to the occlusal plane (4); and from the MC to the alveolar crest (A), to the lower border of the mandible (B) and to the mandibular buccal cortical bone (C). Mandibular thickness (D), width (E) and height (F) of the MC were measured. Intra-class correlation coefficient (ICC) checked the reliability. Two-way ANOVA and Tukey's test were used to compare measurements and classes. Linear measurements 2 presented a statistically significant difference between classes I and II. There was no statistically significant difference between the classes and measurements B, C, D, E and F. Linear measurements A were shorter in class III than in class II. Although most measurements suggest that the BSSO technique does not need to be modified for each skeletal class, measurements from the MF to the mandibular notch in class II and from the MC to the alveolar crest on distal of the second molars in class III could help surgeons to recognize critical regions.

Variations of the Lingula and Mandibular Ramus in the Context of Sagittal Split Ramus Osteotomy: A Cone Beam Computed Tomography Study Supporting an Ethnic-Centric Approach to Orthognathic Surgery.

To investigate the ethnic variations concerning the lingula and ramus of the mandible, with particular emphasis on sagittal split ramus osteotomy (SSRO) in orthognathic surgery. This study examined Cone beam computed tomography (CBCT) scans from the Kenyan and Malay populations. Lingula morphology was classified into four categories. Morphometric measurements included lingula size, height above the occlusal plane, distance to the second mandibular molar, and distance from its apex to all four mandible borders. Regarding the ramus of the mandible, the thickness of each cortical plate, trabecular bone, and overall thickness were determined at two points. Furthermore, points of fusion of cortical plates were determined in both the vertical and horizontal planes. Among Kenyans, the triangular shape was most common (46.5%, n = 80 sides), while truncated was most common among Malays (34.4%, n = 57 sides). The overall mean size of lingula differed significantly between Kenyan (7.37 ± 2.19 mm) and Malay (4.14 ± 2.50 mm) populations (p<0.001). The lingula was more located postero-superiorly in Kenyans compared to Malays (p < 0.001). The mean distance from the distal aspect of the second mandibular molar to the lingula was 38.37 ± 4.98 mm among Kenyans, in contrast to 31.95 ± 0.03 mm among Malays (p < 0.001). The Malays exhibited a thicker mandible with a larger trabecular distance (5.99 ± 1.41 mm and 3.41 ± 1.29 mm, respectively) than Kenyans (5.28 ± 1.39 mm and 1.98 ± 0.98 mm, respectively) (p < 0.001). The points of fusion of the cortical plates differed significantly between Kenyans and Malays. This study focuses on two ethnic groups, Kenyans and Malays, and brings to lightthe ethnic-based differences in the position of the lingula and the dimensions of the mandibular ramus, both of which are essentialconsiderations in orthognathic surgery. Preoperative consideration of such variations is warranted, potentially mitigating iatrogenic injuries and enhancing successful patient outcomes.

Role of platelet rich fibrin in neurosensory recovery following bilateral sagittal split osteotomy - A randomized control trial

Role of platelet rich fibrin in neurosensory recovery following bilateral sagittal split osteotomy - A randomized control trial

Effect of condylar rotation on the stress environment of the temporomandibular joint in patients with mandibular protrusion

PurposeThe study aims to analyse the effects of condylar rotation on the biomechanical environment of the TMJ after bilateral sagittal split ramus osteotomy (BSSRO) through the finite element method (FEM). MethodsThirteen patients with mandibular prognathism and twenty-three normal subjects were recruited. The three-dimensional (3D) models were reconstructed. 13 representative morphological parameters were measured for comparison. A patient was selected to perform virtual BSSRO surgery by rotating the condyles in MIMICS. The preoperative and postoperative 3D models of the patient were subsequently imported into ABAQUS for finite element analysis. The preoperative and postoperative stresses and joint spaces in the TMJs were investigated. ResultsThe maxillofacial morphologies of the patients with mandibular protrusion was significantly different from those of the asymptomatic subjects (P<.05). Stresses in the postoperative group were lower than those in the preoperative group. The rotation of the condyle could cause the variations in stress levels and joint spaces within the TMJs. Inward and upward rotation of the condyle was associated with higher stress in the TMJ, whereas the lowest stress was observed when the condyle remained stationary following surgical intervention. SignificanceLateral, medial and superior joint spaces were more related to the stresses in the TMJs. The condyle should be kept in place as much as possible to avoid disrupting the balance of the TMJ in patients with mandibular protrusion.