• Imaging Science in Dentistry
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• 제52권1호
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• pp.19-25
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• 2022

Purpose: This study evaluated the distance from the posterior root apices to the maxillary sinus floor (MSF) and the frequency of roots touching or protruding through the MSF using cone-beam computed tomography (CBCT). Materials and Methods: This study included 100 subjects divided into different vertical and anteroposterior skeletal growth patterns. On CBCT images, the distance from the posterior root apices to MSF was measured and the frequency of roots touching or protruding through the MSF was evaluated using NNT software (version 5.3.0.0; ImageWorks, Elmsford, NY, USA). Results: No statistically significant differences were found in the distance from the posterior root apices to the MSF among vertical skeletal groups (P>0.05). The palatal roots of the first molar and the palatal, mesio-buccal and disto-buccal roots of the second molars had significantly less distance from MSF in skeletal class II than in class III (P<0.05). The high-angle group had the highest frequencies of roots touching or protruding into the maxillary sinus (49.8%); the lowest proportion of these roots was found in skeletal class III (28.3%) and the highest proportion in class II (50.3%). Males had shorter distances from the posterior root apices to the MSF and higher frequencies of roots protruding through or touching the MSF than females. Conclusion: Anteroposterior skeletal growth patterns and sex affected the distances from the maxillary posterior roots to the MSF. The frequency of roots protruding into or touching the sinus was affected by both vertical and anteroposterior skeletal groups and sex. These findings have implications for dental practice.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제38권
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• pp.18.1-18.9
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• 2016

Background: The aim of this study was to examine the relationship between improvements in lip asymmetry at rest and while smiling after orthognathic surgery in patients with skeletal class III malocclusion. Methods: This study included 21 patients with skeletal class III malocclusion and facial asymmetry. We used preoperative and postoperative CT data and photographs to measure the vertical distance of the lips when smiling. The photographs were calibrated based on these distances and the CT image. We compared preoperative and postoperative results with the t test and correlations between measurements at rest and when smiling by regression analyses. Results: There were significant correlations between the postoperative changes in canting of the mouth corners at rest, canting of the canines, canting of the first molars, the slope of the line connecting the canines, and the slope of the line connecting first molars. The magnitude of the postoperative lip line improvement while smiling was not significantly correlated with changes in the canting and slopes of the canines, molars, and lip lines at rest. Conclusions: It remains difficult to predict lip line changes while smiling compared with at rest after orthognathic surgery in patients with mandibular prognathism, accompanied by facial asymmetry.

• 대한치과교정학회지
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• 제52권5호
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• pp.362-371
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• 2022

Orthognathic surgery is the primary treatment option for severe skeletal discrepancy. However, orthodontic camouflage should be considered as an alternative treatment option, considering the risks of surgery. A 19.5-yearold man presented with a severe prognathic mandible with a Class III molar relationship and an anterior crossbite. Orthognathic surgery could be considered because of his severe skeletal discrepancy and mandibular prognathism. However, the anesthetist for orthognathic surgery did not recommend surgery under general anesthesia because of risk factors associated with the patient's aplastic anemia, including bleeding and infections. Thus, a camouflage treatment to promote backward rotation of the mandible via orthodontic extrusion of the posterior teeth was planned. An anterior bite plate, intermaxillary elastics, and fixed orthodontic appliances were used to extrude the posterior teeth and to align the dentition. After 17 months of nonsurgical orthodontic treatment, normal occlusion was achieved, and the facial profile was dramatically improved. This case report describes the dentoskeletal and soft-tissue effects of mandibular rotation and its long-term stability.

• 대한치과교정학회지
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• 제53권4호
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• pp.219-231
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• 2023

Objective: This study aimed to clarify differences in the positions of cone-beam computed tomography (CBCT) landmarks according to different midsagittal planes (MSPs) in patients with skeletal Class III facial asymmetry. Methods: Pre-treatment CBCT data from 60 patients with skeletal Class III were used. The patients were classified into symmetric (menton deviations of < 2 mm) or asymmetric (menton deviations of > 4 mm) groups. Six MSPs were established based on previous studies, and three-dimensional analyses were performed for the planes in both the groups. The measurement outcomes were compared statistically. Results: A statistically significant interaction (p < 0.01) was observed between MSPs and facial asymmetry. No significant differences were observed among MSPs in the symmetric group. However, significant differences in linear measurements were identified among MSPs in the asymmetric group. Specifically, the upper facial MSP revealed both maxillary and mandibular transverse asymmetries. On the other hand, anterior nasal spine (ANS)-associated MSP could not identify maxillary asymmetry. Furthermore, the menton deviation was approximately 3 mm lower when estimated using the ANS-associated MSP than that using upper facial MSP. Conclusions: The choice of MSP can significantly affect treatment outcomes while diagnosing patients with asymmetry. Therefore, care should be taken when selecting MSP in clinical practice.

• 대한치과교정학회지
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• 제21권2호
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• pp.457-468
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• 1991

This investigation was designed to categorize Angle's class III malocclusion groups through analyzing horizontal and vertical components of craniofacial skeleton in Angle's class III malocclusion. The material selected for this study consisted in standard lateral cephalogram of one hundred and fifty five children, seventy four boys and eighty one girls, aged 6 through 15 years, having Angle's class III malocclusion. On the basis of findings of this study, the following results were obtained. 1. In horizontal skeletal classifications,16 groups were classified FMN-A-B, SE-FMN-A according to the Ba-SE-Me, Ba-SE/R. 2. The sequences that have relatively high frequency are as follow; a) Horizontal Group l b) Horizontal Group 3 c) Horizontal Group 5 d) Horizontal Group 9 e) Horizontal Group 4 3. In vertical skeletal classification, 8 groups were classified according to the PMV/PP, PMV/OP, PMV/MP. 4. The sequences that relatively high are as follows; a) Vertical Group 1 b) Vertical Group 3 c) Vertical Group 4 d) Vertical Group 8.

• 대한치과교정학회지
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• 제45권4호
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• pp.209-214
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• 2015

Maxillary protraction is the conventional treatment for growing Class III patients with maxillary deficiency, but it has undesirable dental effects. The purpose of this report is to introduce an alternative modality of maxillary protraction in patients with dentoskeletal Class III malocclusion using a modified C-palatal plate connected with elastics to a face mask. This method improved skeletal measurements, corrected overjet, and slightly improved the profile. The patients may require definitive treatment in adolescence or adulthood. The modified C-palatal plate enables nonsurgical maxillary advancement with maximal skeletal effects and minimal dental side effects.

• 대한소아치과학회지
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• 제48권2호
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• pp.140-150
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• 2021

이번 연구는 2017 - 2019년에 서울대학교치과병원 소아치과에 내원하여 교정 진단을 받은 580명의 환자를 대상으로 조사를 시행하였다. 이 연구는 소아치과에 내원하는 교정환자의 골격 형태를 측모두부방사선 분석으로 파악하고 골격 형태와 관련된 임상적 특징과의 상관관계를 분석하고자 하였다. 또한, 골격 형태에 따라 행해진 치료방법에 대해 조사하여 임상의가 교정치료 계획 수립시 도움이 되고자 시행되었다. 연령분포는 7세 연령군이 교정진단을 받은 환자 중 가장 많은 분포를 차지하였다. 골격분포는 골격성 1급 부정교합이 54.2%로 가장 많았고 2급은 22.2%, 3급은 23.6%를 차지하였다. 골격성 1급의 경우 상하악 모두 후퇴인 환자가 34.4%, 골격성 2급의 경우 상악은 정상범주이나 하악이 후퇴인 경우가 39.5%, 골격성 3급의 경우 상악 후퇴 및 하악 전돌이 35.0%로 가장 높은 비율을 보였다. 수직적 골격형태는 brachyfacial type이 55%으로 가장 많았고 mesofacial type은 31.9%, dolichofacial type은 13.1%로 나타났다. 전체 환자 중 43.3%가 전치부 반대교합을 보였다.

• 대한치과교정학회지
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• 제52권3호
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• pp.210-219
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• 2022

Objective: The purpose of this study was to examine the effectiveness and mechanism of clear aligner therapy for the correction of anterior open bite in adult nonextraction cases. Methods: Sixty-nine adult patients with anterior open bite were enrolled and classified into Angle's Class I, II, and III groups. Fifty patients presented with skeletal open bite (mandibular plane angle [MPA] ≥ 38°), whereas 19 presented with dental open bite. Fifteen cephalometric landmarks were identified before (T1) and after (T2) treatment. The magnitudes of planned and actual movements of the incisors and molars were calculated. Results: Positive overbite was achieved in 94% patients, with a mean final overbite of 1.1 ± 0.8 mm. The mean change in overbite was 3.3 ± 1.4 mm. With clear aligners alone, 0.36 ± 0.58 mm of maxillary molar intrusion was achieved. Compared with the Class I group, the Class II group showed greater maxillary molar intrusion and MPA reduction. The Class III group showed greater mandibular incisor extrusion with no significant vertical skeletal changes. Conclusions: Clear aligners can be effective in controlling the vertical dimension and correcting mild to moderate anterior open bite in adult nonextraction cases. The treatment mechanism for Class III patients significantly differed from that for Class I and Class II patients. Maxillary incisor extrusion in patients with dental open bite and MPA reduction with mandibular incisor extrusion in patients with skeletal open bite are the most significant contributing factors for open bite closure.

• 대한치과교정학회지
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• 제53권1호
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• pp.54-64
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• 2023

This case report describes skeletal anchorage-supported maxillary protraction performed with the Alternate Rapid Maxillary Expansion and Constriction (AltRAMEC) protocol over a treatment duration of 14 months in a 16-year-old female patient who was in the late growth-development period. Miniplates were applied to the patient's aperture piriformis area to apply force from the protraction appliance. After 9 weeks of following the Alt-RAMEC protocol, miniplates were used to transfer a unilateral 500-g protraction force to a Petit-type face mask. A significant improvement was observed in the soft tissue profile in measurements made both cephalometrically and in three dimensional photographs. Subsequently, the second phase of fixed orthodontic treatment was started and the treatment was completed with the retention phase. Following treatment completion, occlusion, smile esthetics, and soft tissue profile improved significantly in response to orthopedic and orthodontic treatment.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제35권5호
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• pp.316-323
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• 2009

Purpose: This study was performed to evaluate three-dimensional positional change of the condyle using 3D CT after bilateral sagittal split ramus osteotomy (BSSRO) in skeletal class III patients. Patients and methods: Nine patients who underwent BSSRO for mandibular set-back in skeletal class III malocclusion without facial asymmetry were examined. Miniplates were used for the fixation after BSSRO. 3-D CT was taken before, immediately after, and 6 months after undergoing BSSRO. After creating 3D-CT images using V-works $4.0^{TM}$ program, axial plane, coronal plane, & sagittal plane were configured. Three dimensional positional change, from each plane to the condyle, of the nine patients was measured before, immediately after, and 6 months after undergoing BSSRO. Results: 1. The mean value of mandibular set-back for nine mandibular prognathism patients was 7.36 mm (${\pm}\;2.42\;mm$). 2. In the axial view, condyle is rotated inward immediately after BSSRO (p < 0.05), comparing with preoperative but outward 6 months after BSSRO comparing with postoperative (p < 0.05). 3. In the axial view, condyle is moved laterally immediately after BSSRO (p < 0.05), comparing with preoperative but regressed 6 months after BSSRO comparing with preoperative (p > 0.05). 4. In the frontal & coronal view, there is changed immediately after and 6 months after BSSRO, comparing with preoperative but no statistical difference. Conclusion: These results indicate that three-dimensional positional change of the condyle in skeletal class III patients is observed lateral displacement & inward rotation immediate after BSSRO, but the condyle in 6 months after BSSRO tends to regress to preoperative position.