Digital technology revolutionizing mandibular fracture treatment: a comparative analysis of patient-specific plates and conventional titanium plates.

OBJECTIVES: The treatment of fractures prioritizes the restoration of functionality through the realignment of fractured segments. Conventional methods, such as titanium plates, have been employed for this purpose; however, certain limitations have been observed, leading to the development of patient-specific plates. Furthermore, recent advancements in digital technology in dentistry enable the creation of virtual models and simulations of surgical procedures. The aim was to assess the clinical effectiveness of patient-specific plates utilizing digital technology in treating mandibular fractures compared to conventional titanium plates. MATERIALS AND METHODS: Twenty patients diagnosed with mandibular fractures were included and randomly assigned to either the study or control groups. The surgical procedure comprised reduction and internal fixation utilizing patient-specific plates generated through virtual surgery planning with digital models for the study group, while the control group underwent the same procedure with conventional titanium plates. Assessment criteria included the presence of malunion, infection, sensory disturbance, subjective occlusal disturbance and occlusal force in functional maximum intercuspation (MICP). Statistical analysis involved using the Chi-square test and one-way repeated measures analysis of variance. RESULTS: All parameters showed no statistically significant differences between the study and control groups, except for the enhancement in occlusal force in functional MICP, where a statistically significant difference was observed (p = 0.000). CONCLUSION: Using patient-specific plates using digital technology has demonstrated clinical effectiveness in treating mandibular fractures, offering advantages of time efficiency and benefits for less experienced surgeons. CLINICAL RELEVANCE: Patient-specific plates combined with digital technology can be clinically effective in mandibular fracture treatment.

Advancements in computer-assisted orthognathic surgery: A comprehensive review and clinical application in South Korea.

OBJECTIVES: Orthognathic surgery (OS) has evolved with technological advancements, notably through the implementation of computer-assisted orthognathic surgery (CAOS). This article aims to elucidate various types of CAOS and their efficiency and accuracy, supplemented by a thorough literature review focusing on their clinical applications in South Korea. STUDY SELECTION, DATA, AND SOURCES: A comprehensive search strategy was employed, including systematic reviews, meta-analyses, randomized controlled trials, and observational studies published until December 2023 in the PubMed, MEDLINE, and Google Scholar databases. The literature search was limited to articles written in English. RESULTS: Static CAOS demonstrated high precision, reduced operative time, and high accuracy, suggesting its potential reliability in orthognathic procedures. Dynamic CAOS presented a promising avenue for exploration, showing an accuracy comparable to that of traditional methods. The critical considerations for CAOS include accuracy, time efficiency, and cost-effectiveness. Recent studies have indicated advancements in the time efficiency of static CAOS. Static CAOS requires less equipment and is more cost-effective than dynamic CAOS. CONCLUSIONS: CAOS offers clear advantages over conventional OS in terms of surgical convenience and accuracy in implementing the surgical plan. To achieve recognition as the gold standard method for maxillofacial deformity treatment, CAOS must overcome its limitations and undergo continuous verification via well-designed studies. CLINICAL SIGNIFICANCE: The introduction of CAOS, mainly static CAOS with high precision and reduced surgical time, signifies a notable advancement in OS. However, rigorous studies are warranted to validate CAOS as the gold standard for treating maxillofacial deformities.

A Comparative Analysis of Artificial Intelligence and Manual Methods for Three-Dimensional Anatomical Landmark Identification in Dentofacial Treatment Planning.

With the growing demand for orthognathic surgery and other facial treatments, the accurate identification of anatomical landmarks has become crucial. Recent advancements have shifted towards using three-dimensional radiologic analysis instead of traditional two-dimensional methods, as it allows for more precise treatment planning, primarily relying on direct identification by clinicians. However, manual tracing can be time-consuming, mainly when dealing with a large number of patients. This study compared the accuracy and reliability of identifying anatomical landmarks using artificial intelligence (AI) and manual identification. Thirty patients over 19 years old who underwent pre-orthodontic and orthognathic surgery treatment and had pre-orthodontic three-dimensional radiologic scans were selected. Thirteen anatomical indicators were identified using both AI and manual methods. The landmarks were identified by AI and four experienced clinicians, and multiple ANOVA was performed to analyze the results. The study results revealed minimal significant differences between AI and manual tracing, with a maximum deviation of less than 2.83 mm. This indicates that utilizing AI to identify anatomical landmarks can be a reliable method in planning orthognathic surgery. Our findings suggest that using AI for anatomical landmark identification can enhance treatment accuracy and reliability, ultimately benefiting clinicians and patients.

Customized three-dimensional printed ceramic bone grafts for osseous defects: a prospective randomized study.

Ridge resorption can result in insufficient bone volume for implant surgery, necessitating bone substitutes to restore the resorption area. Recent advances in computer-aided design and manufacturing enable the use of alloplastic bone graft materials with customizable compositions or shapes. This randomized study evaluated the clinical effectiveness of a customized three-dimensional (3D) printed alloplastic bone material. Sixty patients requiring guided bone regeneration for implant installation following tooth extraction due to alveolar bone resorption were recruited at two institutions. The participants were randomly allocated to either a group that received 3D-printed patient-customized bone graft material or a group that received conventional block bone graft material. Implant installation with bone harvesting was performed approximately 5 months after bone grafting. Histological and radiological assessments of the harvested bone area were performed. The experimental group had a significantly higher percent bone volume and a smaller tissue surface than the control group. Bone volume, bone surface, bone surface/volume ratio, bone surface density (bone surface/total volume), and bone mineral density did not differ significantly between groups. Patient-customized bone graft materials offer convenience and reduce patient discomfort. The findings suggest 3D-printed patient-customized bone graft materials could be used as an alternative for simpler bone grafting procedures.

Current Status of Recombinant Human Bone Morphogenetic Protein-2 (rhBMP-2) in Maxillofacial Surgery: Should It Be Continued?

Recombinant human bone morphogenetic protein-2 (rhBMP-2) has shown potential in maxillofacial surgery owing to its osteoinductive properties. However, concerns about its safety and high cost have limited its widespread use. This review presents the status of rhBMP-2 use in maxillofacial surgery, focusing on its clinical application, efficacy, safety, and limitations. Studies have demonstrated rhBMP-2's potential to reduce donor site morbidity and increase bone height in sinus and ridge augmentation; however, it may not outperform autogenous bone grafts. In medication-related osteonecrosis of the jaw treatment, rhBMP-2 has been applied adjunctively with promising results, although its long-term safety requires further investigation. However, in maxillofacial trauma, its application is limited to the restoration of large defects. Safety concerns include postoperative edema and the theoretical risk of carcinogenesis. Although postoperative edema is manageable, the link between rhBMP-2 and cancer remains unclear. The limitations include the lack of an ideal carrier, the high cost of rhBMP-2, and the absence of an optimal dosing regimen. In conclusion, rhBMP-2 is a promising graft material for maxillofacial surgery. However, it has not yet become the gold standard owing to safety and cost concerns. Further research is required to establish long-term safety, optimize dosing, and develop better carriers.

Patient-specific plates for facial fracture surgery: A retrospective case series.

OBJECTIVES: Surgeons often encounter challenges when treating maxillofacial fractures using conventional methods that involve trimming or bending ready-made titanium plates for open reduction and internal fixation (ORIF) since it can be time-consuming, imprecise, and inconvenient. This retrospective case series aimed to introduce a novel bone reduction method that utilizes virtual planning, patient-specific surgical guides, and titanium plates. METHODS: Seven patients with mandibular symphysis or subcondylar fractures resulting from facial trauma underwent cone-beam computed tomography (CBCT) or facial CT scans, and their medical histories were documented. Virtual surgery was conducted based on three-dimensional (3D) stereolithography images derived from CT scans using the FaceGide software (MegaGen, Daegu, Korea). ORIF was performed using patient-specific surgical guides and plates that were designed, printed, and milled. Radiographic, clinical, and occlusal evaluations were conducted at two weeks and six weeks postoperatively. Subsequently, 3D images from virtual surgery and postoperative CT scans were compared. RESULTS: The comparison of 3D virtual surgery and postoperative images revealed minimal surface differences of less than 1 mm. T-scan evaluations indicated that there were no statistically significant differences between the two- and six-week postoperative assessments. Favorable clinical outcomes were observed. CONCLUSION: This novel method demonstrated stable outcomes in terms of occlusion and healing, with no notable complications. Consequently, this approach may serve as a viable alternative to conventional methods. CLINICAL SIGNIFICANCE: Facial fracture surgery that utilizes patient-specific surgical guides and plates within a digital workflow can facilitate meticulous surgical planning, reducing the risk of complications and minimizing operation time.

Clinical Stability of Bespoke Snowman Plates for Fixation following Sagittal Split Ramus Osteotomy of the Mandible.

Maxillofacial skeletal surgery often involves the use of patient-specific implants. However, errors in obtaining patient data and designing and manufacturing patient-specific plates and guides can occur even with accurate virtual surgery. To address these errors, bespoke Snowman plates were designed to allow movement of the mandible. This study aimed to compare the stability of bespoke four-hole miniplates with that of a bespoke Snowman plate for bilateral sagittal split ramus osteotomy (SSRO), and to present a method to investigate joint cavity changes, as well as superimpose virtual and actual surgical images of the mandible. This retrospective study included 22 patients who met the inclusion criteria and underwent orthognathic surgery at a university hospital between 2015 and 2018. Two groups were formed on the basis of the plates used: a control group with four-hole bespoke plates and a study group with bespoke Snowman plates. Stability was assessed by measuring the condyle-fossa space and superimposing three-dimensional virtual surgery images on postoperative cone-beam computed tomography (CBCT) scans. No significant differences were observed in the condyle-fossa space preoperatively and 1 year postoperatively between the control and study groups. Superimposing virtual surgery and CBCT scans revealed minimal differences in the landmark points, with no variation between groups or timepoints. The use of bespoke Snowman plates for stabilizing the mandible following SSRO exhibited clinical stability and reliability similar to those with bespoke four-hole plates. Additionally, a novel method was introduced to evaluate skeletal stability by separately analyzing the condyle-fossa gap changes and assessing the mandibular position.

Clinical Significance of Intraoperative Exposure of Inferior Alveolar Nerve during Surgical Extraction of the Mandibular Third Molar in Nerve Injury.

During extraction surgery, the inferior alveolar nerve (IAN) can occasionally be observed in the extraction socket of the mandibular third molar (M3). The purpose of this study was to investigate and compare the incidence of IAN injury in groups with and without intraoperative IAN exposure during surgical extraction of M3, and to identify additional risk factors for the IAN injury in addition to the IAN exposure. A total of 288 cases in 240 patients, who underwent surgical extraction of M3 by a single surgeon, were divided into the exposed group (n = 69) and the unexposed group (n = 219). The surgeon recorded the information regarding the procedure when the clinical observation of IAN exposure was made during the surgery. The incidence of IAN injury after the extraction surgery was significantly higher in the exposed group than in the unexposed group (4.3% versus 0%, p < 0.05). Paresthesia was recognized in three cases of the exposed group, but it showed complete recovery within three postoperative months. No case of permanent paresthesia was detected in both groups. According to the logistic regression, the only significant risk factor of IAN injury in the exposed group was the increase of age (OR 1.108, p < 0.05). Intraoperative IAN exposure during surgical extraction of M3 may show a higher incidence of IAN injury than the case without IAN exposure, representing an incidence of 4.3%. Even if the paresthesia associated with IAN exposure occurs, it is likely to be a temporary injury, and this risk may increase with age.

Correction of Condylar Displacement of the Mandible Using Early Screw Removal following Patient-Customized Orthognathic Surgery.

OBJECTIVE: Orthognathic surgery (OGS) is a surgical intervention that corrects dentofacial deformities through the movement of maxillary and mandibular segments to achieve adequate masticatory function, joint health, and facial harmony. However, some patients present with occlusal discrepancies, condylar sag, and/or temporomandibular disorders after OGS. Various methods have been employed to solve these problems after surgery. This study aimed to evaluate the effectiveness of early screw removal in patients with occlusal discrepancies after OGS using three-dimensional cone-beam computed tomography (CBCT). METHODS: In 44 patients with dentofacial deformities, patient-customized OGSs with customized plates were performed to correct facial deformities using customized guides with computer-aided surgical simulation. Of the 44 patients, eight patients complained of occlusal discrepancies and temporomandibular disorders after OGS. These eight patients underwent screw removal under local anesthesia around four weeks. The temporomandibular joint spaces at three time points (pre-surgical, post-surgical, and after screw removal) in the sagittal and coronal planes were compared using CBCT. RESULTS: Eight patients showed an increase in joint space on CBCT images immediately after surgery (T1), but after early screw removal (T2), these spaces almost returned to their pre-surgical state, and the temporomandibular joint problem disappeared. CONCLUSIONS: The removal of screws located in the distal segment under local anesthesia between three and four weeks post-surgically may be a treatment option for patients with post-OGS occlusal discrepancies, condylar sag, and/or temporomandibular disorder.

Various Therapeutic Methods for the Treatment of Medication-Related Osteonecrosis of the Jaw (MRONJ) and Their Limitations: A Narrative Review on New Molecular and Cellular Therapeutic Approaches.

Medication-related osteonecrosis of the jaw (MRONJ) is one of the most interesting diseases in the field of maxillofacial surgery. In addition to bisphosphonates, the use of antiresorptive and antiangiogenic agents is known to be the leading cause. However, the exact pathogenesis of MRONJ has not been established, and various hypotheses have been proposed, such as oxidative stress-related theory. As a result, a definitive treatment protocol for MRONJ has not been identified, while various therapeutic approaches are applied to manage patients with MRONJ. Although the surgical approach to treat osteomyelitis of the jaw has been proven to be most effective, there are limitations, such as recurrence and delayed healing. Many studies and clinical trials are being conducted to develop another effective therapeutic modality. The use of some materials, including platelet concentrates and bone morphogenetic proteins, showed a positive effect on MRONJ. Among them, teriparatide is currently the most promising material, and it has shown encouraging results when applied to patients with MRONJ. Furthermore, cell therapy using mesenchymal stem cells showed promising results, and it can be the new therapeutic approach for the treatment of MRONJ. This review presents various treatment methods for MRONJ and their limitations while investigating newly developed and researched molecular and cellular therapeutic approaches along with a literature review.

Analysis of the relationship between periodontitis and osteoporosis/fractures: a cross-sectional study.

BACKGROUND: Chronic periodontitis is a multifactorial inflammatory disease resulting in patients exhibiting high levels of inflammatory factors causing systemic inflammatory bone destruction that may lead to osteoporosis development. The association between periodontitis and osteoporosis has been documented; however, the findings remain unclear. This study aimed to identify the association between periodontitis and osteoporosis using a cross-sectional study design and Korean Genome and Epidemiology Study (KoGES) health examinee data. METHODS: This cross-sectional study used epidemiological data from the KoGES during 2004-2016. Of 125,324 participants (age, 40-79 years), 9969 with periodontitis and 115,332 controls (without periodontitis) were selected. We analyzed the history of osteoporosis and fractures of all participants. All participants were examined according to age, sex, income group, obesity, smoking habits, alcohol consumption, and food intake. To analyze the odds ratio (OR) of periodontitis for those with osteoporosis and fractures, a logistic regression model was used. RESULTS: The adjusted odds ratio (aOR) of periodontitis for osteoporosis was 2.16 (95% confidence interval [CI], 2.01-2.31; P < 0.001). The aOR of periodontitis for any fracture was 1.54 (95% CI 1.46-1.62; P < 0.001). CONCLUSION: Osteoporosis and fractures are associated with periodontitis. Performing regular oral hygiene and examinations of bone mineral density are recommended to prevent aggravation of osteoporosis and periodontitis.

Comparison of Changes in the Condylar Volume and Morphology in Skeletal Class III Deformities Undergoing Orthognathic Surgery Using a Customized versus Conventional Miniplate: A Retrospective Analysis.

With the great leap in the development of three-dimensional computer-assisted surgical technology, surgeons can use a variety of assistive methods to achieve better results and evaluate surgical outcomes in detail. This retrospective study aimed to evaluate the postoperative stability after bilateral sagittal split ramus osteotomy by volume rendering methods and to evaluate how postoperative stability differs depending on the type of surgical plate. Of the patients who underwent BSSRO, ten patients in each group (non-customized miniplate and customized miniplate) who met the inclusion criteria were selected. Preoperative and postoperative cone-beam computed tomography data were collected, and condylar morphological and landmark measurements were obtained using Checkpoint and OnDemand software, respectively. The postoperative condylar morphological dataset revealed no significant difference (p > 0.05) between the two groups. No significant difference (p > 0.05) was observed between the two groups in horizontal, vertical, or angular landmark measurements used to quantify operational stability. These results indicate that there is no difference in the surgical outcome between the patient-specific system and the conventional method, which will allow clinicians to take advantage of the patient-specific system for this surgical procedure, with favorable results, as with the conventional method.

Increased Risk of Migraine in Patients with Temporomandibular Disorder: A Longitudinal Follow-Up Study Using a National Health Screening Cohort.

BACKGROUND: The aim of this study was to investigate the association between temporomandibular disorder (TMD) and migraine through a longitudinal follow-up study using population data from a national health screening cohort. METHODS: This cohort study used data from the Korean National Health Insurance Service-Health Screening Cohort from 2002 to 2015. Of the 514,866 participants, 3884 TMD patients were matched at a 1:4 ratio with 15,536 control participants. Crude models and models adjusted for obesity, smoking, alcohol consumption, systolic blood pressure, diastolic blood pressure, fasting blood glucose, total cholesterol, and Charlson Comorbidity Index (CCI) scores were calculated. Chi-squared test, Kaplan-Meier analysis, and two-tailed log-rank test were used for statistical analysis. Stratified Cox proportional hazard models were used to assess hazard ratios (HR) and 95% confidence intervals (CIs) for migraine in both control groups. RESULTS: The adjusted HR for migraine was 2.10 (95% CI: 1.81-2.44) in the TMD group compared to the control group, which was consistent in subgroup analyses according to age, sex, and Kaplan-Meier analysis. CONCLUSIONS: This study demonstrated that TMD patients have a higher risk of migraine. These results suggest that dentists can decrease the risk of migraine in TMD patients by managing TMD properly.

Bioabsorbable Osteofixation Materials for Maxillofacial Bone Surgery: A Review on Polymers and Magnesium-Based Materials.

Clinical application of osteofixation materials is essential in performing maxillofacial surgeries requiring rigid fixation of bone such as trauma surgery, orthognathic surgery, and skeletal reconstruction. In addition to the use of titanium plates and screws, clinical applications and attempts using bioabsorbable materials for osteofixation surgery are increasing with demands to avoid secondary surgery for the removal of plates and screws. Synthetic polymeric plates and screws were developed, reaching satisfactory physical properties comparable to those made with titanium. Although these polymeric materials are actively used in clinical practice, there remain some limitations to be improved. Due to questionable physical strength and cumbersome molding procedures, interests in resorbable metal materials for osteofixation emerged. Magnesium (Mg) gained attention again in the last decade as a new metallic alternative, and numerous animal studies to evaluate the possibility of clinical application of Mg-based materials are being conducted. Thanks to these researches and studies, vascular application of Mg-based biomaterials was successful; however, further studies are required for the clinical application of Mg-based biomaterials for osteofixation, especially in the facial skeleton. The review provides an overview of bioabsorbable osteofixation materials in maxillofacial bone surgery from polymer to Mg.

A Simple and Safe Approach for Maxillary Sinus Augmentation with the Advanced Surgical Guide.

OBJECTIVE: The development of digital dentistry has contributed to the astonishing advancement of implant dentistry. Furthermore, digital technology is expected to be applied extensively to sinus augmentation, which is an advanced technique for implant surgery. This study introduces a simple method for a safer and more precise lateral window opening for sinus augmentation using a navigation program. METHODS: Five eligible patients with residual alveolar bone of 4 mm or less are presented, requiring lateral approach for sinus augmentation. Navigation system was opted for the sinus lift with simultaneous implant placement. Virtual planning started with establishing the adequate position of the lateral window based on the radiographic images and the scanned file of the dentition. The position of the window was indicated on the guide within the program. Afterwards, the virtually designed surgical guide was fabricated either with 3D printer or milling machine for the actual surgery. RESULTS: All the patients who underwent surgery with the surgical guide showed no sign of clinical complications including pain, swelling, nausea, epistaxis, or early loss of the implants. Results of radiographic evaluation also showed adequate placement of the implants in a pre-planned position, and the sinus window was also formed in the desired location. CONCLUSION: Lateral window opening combined with digital navigation system is believed to be a promising technique for a more precise as well as safer sinus augmentation.

Long-term Stability after Reduction of Mandible Fracture by Keyhole Plate: Evaluation at the Time of Plate Removal.

BACKGROUND: Various types of miniplates have been developed and used for the reduction of facial bone fractures. We introduced Yang's Keyhole (YK) plate, and reported on its short-term stability. The purpose of this study was to evaluate the long-term stability of the YK plate, as a follow-up study, by examining the patients who had used the YK plate among the patients with the reduction of mandible fractures and who visited for plate removal. METHODS: We reviewed the medical records of 16 patients who underwent mandibular fracture fixation using a YK plate (group I) and 17 patients who underwent mandibular fracture fixation using a conventional plate (group II). Assessment was then made on malunion, occlusal stability, discomfort during the application, and clinical symptoms. RESULTS: From January 2015 to December 2017, a total of 36 patients underwent mandibular fracture surgery using a YK plate. A total of 16 patients received plate removal. Among them, 15 were male and 1 female. The average age was 26 years. The applied surgical sites were the 12 on mandibular angle, 4 on mandibular symphysis, and 2 on subcondyle. The application period of YK plate was an average of 335 days. During the same period, 45 people underwent surgery on the conventional plate. A total of 17 patients received plate removal. Among them, 15 were male and 2 females. The average age was 36 years. The applied surgical sites were the 8 on mandibular angle, 4 on mandibular symphysis, and 2 on subcondyle. The application period of the conventional plate was an average of 349 days. No malocclusion occurred at the time of removal, and occlusion was stable. No patient complained of joint disease or discomfort. CONCLUSION: The YK plate system, in which the screw was first inserted and the plate was applied, for clinical convenience did not cause any particular problem and no significant difference from the conventional plate.

Delayed Reconstruction of Palatomaxillary Defect Using Fibula Free Flap.

INTRODUCTION: The objective of this study was to evaluate a surgical technique and to present the results of delayed reconstruction of palatomaxillary defects using fibula free flap (FFF). METHODS: A review was conducted for nine patients who underwent palatomaxillary reconstruction using FFF. Primary disease, type of reconstruction, defect area, fibula segment length and number of osteotomies, radiotherapy, and implant installation after FFF reconstruction were analyzed. RESULTS: All nine patients underwent delayed reconstruction. The fibula shaft was osteotomized into two segments in seven patients and three segments in one patient with bilateral Brown's revised classification IV/d defect. One case was planned by using a computer-aided design computer-aided manufacturing (CAD/CAM) system with a navigation system. The mean length of the grafted fibula bone was 68.06 mm. Dental implant treatment was performed in six patients. Six patients received radiation therapy, and there were no specific complications related to the radiation therapy. In one case, the defect was reconstructed with FFF flow-through from a radial forearm free flap. CONCLUSION: This clinical study demonstrated that the fibula flap is an ideal donor-free flap in a palatomaxillary defect. Delayed reconstruction using an FFF can reduce the complication and failure rates.

Anterior Segmental Osteotomy Using Customized Spider-Plates Based on Computer-aided Surgery System.

Anterior segmental osteotomy (ASO) is considered the treatment modality of choice in patients with the bimaxillary dentoalveolar protrusion. However, this meticulous surgical technique accompanies a number of possible disadvantages. The considerable time required before, during, and after the operation, limited movement of the segment, damage of the mental nerve, loss of tooth vitality, loss of a tooth or teeth, or indeed total loss of the anterior segments are those that affect the result of the surgery. Recently, the authors have devised a computer-aided surgical simulation programme and fabricated the customized osteotomy guides and the spider-shaped plates based on the programme. They were then applied to a 28-year-old patient with the complaint of a bimaxillary dentoalveolar protrusion. This approach helped to overcome several problems related to ASO reported earlier.

Retrospective comparative clinical study for silk mat application into extraction socket.

BACKGROUND: Silk mats have been approved for clinical trials by the Korean Food and Drug Administration as membranes for guided tissue regeneration (GTR). In this study, silk mat application was compared to high-density polytetrafluoroethylene (dPTFE) membrane application or no membrane group. METHODS: To compare the silk mat group to the dPTFE group or the no membrane group, a retrospective sample collection was conducted. Bony defects were measured at the time of extraction (T0) and then at 3 months (T1) and 6 months after extraction (T2) on a digital panoramic view. Bone gain (BG) was calculated by subtracting from the bony defect at T0 to the bony defect at each follow-up. RESULTS: The BG at T2 was 2.44 ± 2.49 mm, 4.18 ± 1.80 mm, and 4.24 ± 2.05 mm in the no membrane group, silk mat group, and dPTFE group, respectively. Both membrane groups had significantly higher BG than BG in the no membrane group at T2 (P < 0.05). CONCLUSIONS: Both membrane groups showed higher BG than the no membrane group.

Three-dimensional assessment of condylar position following orthognathic surgery using the centric relation bite and the ramal reference line: A retrospective clinical study.

Orthognathic surgery (OGS) is a relatively common procedure for solving functional and aesthetic problems in facial and jaw areas in patients with dentofacial deformities. The positioning of the mandibular condylar segment during OGS has an impact on the surgical outcome. This study aimed to investigate the changes in the condyle-fossa relationship three dimensionally after OGS using the centric relation (CR) bite and the ramal reference line (RRL).Thirty-two patients with skeletal malocclusion underwent OGS. Condylar repositioning was performed using the CR bite, as previously reported. A RRL was added to the existing method and used during the surgery. Cone-beam computed tomography scans were acquired at 4 time points. Sixty-four condyles were evaluated in the coronal, sagittal, and axial views. Two groups were created according to the amount of mandible setback (SB1 vs SB2), and another 2 groups were created according to the maxillary operation (1-jaw vs 2-jaw). Each was then compared at the 4 time points. Differences between the values before (T0) and a year after surgery (T3) were also investigated. The positions of the pogonion and the menton were examined at T2 and T3 for the simple evaluation of relapse.The change in the condylar position was significant over a time-course (P < .001) but not between T0 and T3 (P > .05). Neither the setback amount nor the maxillary operation affected the positional change (P > .05). There were no significant changes between T2 and T3 in the relapse evaluation.This condylar repositioning method using the CR bite and a RRL showed stable results after OGS. This method is noninvasive and cost-effective and can be easily performed even by an inexperienced surgeon because it reduces errors in repositioning the condyle during OGS.