• 대한치과교정학회지
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• 제49권4호
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• pp.254-264
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• 2019

Objective: To evaluate the short-term changes in masticatory muscle activity and mandibular movement patterns after orthognathic surgery in skeletal Class III patients with facial asymmetry. Methods: Twenty-seven skeletal Class III adult patients were divided into two groups based on the degree of facial asymmetry: the experimental group (n = 17 [11 male and 6 female]; menton deviation ${\geq}4mm$) and control group (n = 10 [4 male and 6 female]; menton deviation < 1.6 mm). Cephalography, electromyography (EMG) for the anterior temporalis (TA) and masseter muscles (MM), and mandibular movement (range of motion [ROM] and average chewing pattern [ACP]) were evaluated before (T0) and 7 to 8 months (T1) after the surgery. Results: There were no significant postoperative changes in the EMG potentials of the TA and MM in both groups, except in the anterior cotton roll biting test, in which the masticatory muscle activity had changed into an MM-dominant pattern postoperatively in both groups. In the experimental group, the amount of maximum opening, protrusion, and lateral excursion to the non-deviated side were significantly decreased. The turning point tended to be shorter and significantly moved medially during chewing in the non-deviated side in the experimental group. Conclusions: In skeletal Class III patients with facial asymmetry, the EMG activity characteristics recovered to presurgical levels within 7 to 8 months after the surgery. Correction of the asymmetry caused limitation in jaw movement in terms of both ROM and ACP on the non-deviated side.

• 대한치과교정학회지
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• 제52권1호
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• pp.66-74
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• 2022

Objective: To investigate demographic and skeletodental characteristics of one-jaw (1J-OGS) and two-jaw orthognathic surgery (2J-OGS) in patients with skeletal Class III malocclusion. Methods: 750 skeletal Class III patients who underwent OGS at 10 university hospitals in Korea between 2015 and 2019 were investigated; after dividing them into the 1J-OGS (n = 186) and 2J-OGS groups (n = 564), demographic and skeletodental characteristics were statistically analyzed. Results: 2J-OGS was more frequently performed than 1J-OGS (75.2 vs. 24.8%), despite regional differences (capital area vs. provinces, 86.6 vs. 30.7%, p < 0.001). Males outnumbered females, and their mean operation age was older in both groups. Regarding dental patterns, the most frequent maxillary arch length discrepancy (ALD) was crowding in the 1J-OGS group (52.7%, p < 0.001) and spacing in the 2J-OGS group (40.4%, p < 0.001). However, the distribution of skeletal pattern was not significantly different between the two groups (all p > 0.05). The most prevalent skeletal patterns in both groups were hyper-divergent pattern (50.0 and 54.4%, respectively) and left-side chin point deviation (both 49.5%). Maxillary spacing (odds ratio [OR], 3.645; p < 0.001) increased the probability of 2J-OGS, while maxillary crowding (OR, 0.672; p < 0.05) and normo-divergent pattern (OR, 0.615; p < 0.05) decreased the probability of 2J-OGS. Conclusions: In both groups, males outnumbered females, and their mean operation age was older. The most frequent ALD was crowding in the 1J-OGS group, and spacing in the 2J-OGS group, while skeletal characteristics were not significantly different between the two groups.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제39권
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• pp.1.1-1.7
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• 2017

Background: Multiple myeloma (MM) is characterized by a neoplastic proliferation of plasma cells primarily in the bone marrow. Bisphosphonates (BP) are used as supportive therapy in the management of MM. This study aimed to analyze the incidence, risk factors, and clinical outcomes of medication-related necrosis of the jaw (MRONJ) in MM patients. Methods: One hundred thirty MM patients who had previous dental evaluations were retrospectively reviewed. Based on several findings, we applied the staging and treatment strategies on MRONJ. We analyzed gender, age, type of BP, incidence, and local etiological factors and assessed the relationship between these factors and the clinical findings at the first oral examination. Results: MRONJ was found in nine male patients (6.9%). The mean patient age was 62.2 years. The median BP administration time was 19 months. Seven patients were treated with a combination of IV zoledronate and pamidronate, and two patients received single-agent therapy. The lesions were predominantly located in the mandible (n = 8), and the most common predisposing dental factor was a history of prior extraction (n = 6). Half of the MRONJ were related to diseases found on the initial dental screen. Patients with MRONJ were treated with infection control and antibiotic therapy. When comparing between the MRONJ stage and each factor (sign, location, etiologic factor, BP type, treatment, and outcome), there were no significant differences between stages, except for between the stage and sign (with or without purulence). Conclusions: For prevention of MRONJ, we recommend routine dental examinations and treatment prior to starting BP therapy.

• 대한치과교정학회지
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• 제52권4호
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• pp.287-297
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• 2022

Objective: To investigate the pattern of accuracy change in artificial intelligence-assisted landmark identification (LI) using a convolutional neural network (CNN) algorithm in serial lateral cephalograms (Lat-cephs) of Class III (C-III) patients who underwent two-jaw orthognathic surgery. Methods: A total of 3,188 Lat-cephs of C-III patients were allocated into the training and validation sets (3,004 Lat-cephs of 751 patients) and test set (184 Lat-cephs of 46 patients; subdivided into the genioplasty and non-genioplasty groups, n = 23 per group) for LI. Each C-III patient in the test set had four Lat-cephs: initial (T0), pre-surgery (T1, presence of orthodontic brackets [OBs]), post-surgery (T2, presence of OBs and surgical plates and screws [S-PS]), and debonding (T3, presence of S-PS and fixed retainers [FR]). After mean errors of 20 landmarks between human gold standard and the CNN model were calculated, statistical analysis was performed. Results: The total mean error was 1.17 mm without significant difference among the four time-points (T0, 1.20 mm; T1, 1.14 mm; T2, 1.18 mm; T3, 1.15 mm). In comparison of two time-points ([T0, T1] vs. [T2, T3]), ANS, A point, and B point showed an increase in error (p < 0.01, 0.05, 0.01, respectively), while Mx6D and Md6D showeda decrease in error (all p < 0.01). No difference in errors existed at B point, Pogonion, Menton, Md1C, and Md1R between the genioplasty and non-genioplasty groups. Conclusions: The CNN model can be used for LI in serial Lat-cephs despite the presence of OB, S-PS, FR, genioplasty, and bone remodeling.

• 대한치과교정학회지
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• 제54권2호
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• pp.89-107
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• 2024

Objective: This systematic review aimed to provide a comparative analysis of the treatment outcomes, including hard and soft tissues, postoperative stability, temporomandibular disorders (TMD), and quality of life (QoL), in patients with facial asymmetry who underwent orthognathic surgery. Methods: The primary objective was to address the question, "How do different factors related to surgery affect the outcomes and stability of orthognathic surgery in the correction of facial asymmetry?" A meta-analysis was conducted on the outcome parameters, such as skeletal, dental, and soft tissue symmetry, TMD, QoL, and relapse, using the Hartung-Knapp-Sidik-Jonkman method for random-effects models. Subgroup analyses were conducted considering surgery-related factors such as surgical techniques (one-jaw vs. two-jaw), use of the surgery-first approach, utilization of computer simulation, and analytical methods employed to evaluate asymmetry (2D vs. 3D). Results: Forty-nine articles met the inclusion criteria. The metaanalysis demonstrated a significant improvement in the symmetry of hard and soft tissues. The subgroup analysis indicated that the treatment outcomes showed significant improvement, regardless of the factors related to surgery. Changes in TMD signs and symptoms varied according to the surgical technique used. Quality of life improved in the facial, oral, and social domains. Skeletal relapse was observed during the follow-up. Conclusions: Our findings support the positive outcomes of orthognathic surgery in the treatment of facial asymmetry in terms of skeletal and soft tissue improvements, stability, relief of TMD symptoms, and enhancement of QoL. However, most of the included studies showed a low certainty of evidence and high heterogeneity.

• Journal of International Society for Simulation Surgery
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• 제3권2호
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• pp.60-63
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• 2016

Fibrous dysplasia is quite a rare disease usually involving maxilla and mandible. Because of its benign clinical course, conservative contouring surgery has been recommended for facial deformity. 3D rapid prototype (RP) model gives a lot of informations before operation such as depth of drilling, area of resection and important anatomic structure. The purpose of this study was to report maxilla-mandibular contouring surgery in fibrous dysplasia patients. A total of 14 consecutive patients were included for surgical and esthetic evaluation. Among 14 patients, RP model study was performed in two patients with severe facial deformity. The other patients underwent contouring surgery under conventional methods. Surgical evaluation was performed with computed tomography scan before and after operation. Surgical resection was successful and patients were satisfied with the surgical results.

• 대한치과의사협회지
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• 제52권4호
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• pp.192-202
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• 2014

Bisphosphonate(BP) significantly influence the hone remodeling process. Increasing number of patients with osteoporosis and metastatic bone disease need high dose or long term bisphosphonate therapy. Major adverse effect is jaw bone necrosis and now the bisphosphonate-related necrosis of the jaw(BRONJ) is the major concern of dental practitioner. This study intended to perform the review of the current understandings concerning the pathophysiology of BRONJ. Even though pathophysiological mechanism of BRONJ is not clearly elucidated but now suggested as largely two different concepts; so-called "inside-out" or "outside-in" theory. Inside-out theory emphasize the osteonecrosis of the jaw is the initial major event and subsequent infection and inflammation is the second event that accompanies bone exposure and death of overlying mucosa. However, in "outside-in" theory, infection or inflammation initiated by traumatized oral epithelium is the major event of BRONJ. Both theory would be partially explain BRONJ. Recent research reveals the immune modulating effect and influence of microcrack accumulation by BP. These findings and those of others might explain the missing part of outside-in theory.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제38권
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• pp.13.1-13.12
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• 2016

Background: Mandibular motion tracking system (ManMoS) has been developed for orthognathic surgery. This article aimed to introduce the ManMoS and to examine the accuracy of this system. Methods: Skeletal and dental models are reconstructed in a virtual space from the DICOM data of three-dimensional computed tomography (3D-CT) recording and the STL data of 3D scanning, respectively. The ManMoS uniquely integrates the virtual dento-skeletal model with the real motion of the dental cast mounted on the simulator, using the reference splint. Positional change of the dental cast is tracked by using the 3D motion tracking equipment and reflects on the jaw position of the virtual model in real time, generating the mixed-reality surgical simulation. ManMoS was applied for two clinical cases having a facial asymmetry. In order to assess the accuracy of the ManMoS, the positional change of the lower dental arch was compared between the virtual and real models. Results: With the measurement data of the real lower dental cast as a reference, measurement error for the whole simulation system was less than 0.32 mm. In ManMoS, the skeletal and dental asymmetries were adequately diagnosed in three dimensions. Jaw repositioning was simulated with priority given to the skeletal correction rather than the occlusal correction. In two cases, facial asymmetry was successfully improved while a normal occlusal relationship was reconstructed. Positional change measured in the virtual model did not differ significantly from that in the real model. Conclusions: It was suggested that the accuracy of the ManMoS was good enough for a clinical use. This surgical simulation system appears to meet clinical demands well and is an important facilitator of communication between orthodontists and surgeons.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제37권6호
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• pp.470-476
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• 2011

Introduction: The incidence of bisphosphonate-related osteonecrosis of the jaw (BRONJ) has increased gradually in patients who have undergone surgical treatment for osteomyelitis. In this study, a retrospective analysis of BRONJ patients was carried out using the data of osteomyelitis patients treated surgically. Materials and Methods: Osteomyelitis patients, who underwent curettage, sequestrectomy, saucerization or decortications, and partial mandibulectomy at Seoul National University Dental Hospital from 2004 to 2010 were enrolled in this study. The patients were classified and categorized into two groups based on the surgical records and progress notes. One group comprised of patients with osteomyelitis and osteoporosis, and the other group included patients with osteomyelitis only. The epidemiological data of the BRONJ patients was analyzed to identify any trend in the incidence of BRONJ in osteomyelitis patients. Results: Among 200 patients who underwent surgical intervention for osteomyelitis, 64 (32.0%) were identified as having osteoporosis as the underlying disease. In these 64 patients, more than 81.3% had been prescribed bisphosphonates. Females were far more affected by BRONJ than males. The incidence of BRONJ also increased with age. The posterior part of the mandible was affected more frequently by BRONJ. Conclusion: Although the availability of potent antibiotics and increased oral hygiene care can reduce the overall incidence of osteomyelitis, BRONJ can increase the total incidence. To prevent BRONJ, it is recommended that an oral examination be performed before prescribing bisphosphonates. Moreover, the patients should be educated about the potential risks of dental procedures that might be causal factors for BRONJ. Furthermore, patient swho take bisphosphonates for the treatment of osteoporosis should undergo periodic follow up oral examinations to prevent BRONJ.

• 대한치과의사협회지
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• 제15권3호
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• pp.205-208
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• 1977

The etiology of masseteric hypertrophy is obscure. When the hypertrophy occurs unilaterally it's appearance is more striking because of the resultant facial asymmetry. Two soldiers were admitted with the complaint of a lump on their jaws. The authors obtained good results on the esthetic & functional aspect in two cases of unilateral masseteric hypertrophy with the Adam's method. The etiology was thought to be the combination of unilateral masticatory and jaw clenching habits when emotionally disturbed or under nervous tension in army services.