• 대한치과교정학회지
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• 제51권5호
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• pp.337-345
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• 2021

Objective: To investigate the phenotypes and predominant skeletodental pattern in pre-adolescent patients with Pierre-Robin sequence (PRS). Methods: The samples consisted of 26 Korean pre-adolescent PRS patients (11 boys and 15 girls; mean age at the investigation, 9.20 years) treated at the Department of Orthodontics, Seoul National University Dental Hospital between 1998 and 2019. Dental phenotypes, oral manifestation, cephalometric variables, and associated anomalies were investigated and statistically analyzed. Results: Congenitally missing teeth (CMT) were found in 34.6% of the patients (n = 9/26, 20 teeth, 2.22 teeth per patient) with 55.5% (n = 5/9) exhibiting bilaterally symmetric missing pattern. The mandibular incisors were the most common CMT (n = 11/20). Predominant skeletodental patterns included Class II relationship (57.7%), posteriorly positioned maxilla (76.9%) and mandible (92.3%), hyper-divergent pattern (92.3%), high gonial angle (65.4%), small mandibular body length to anterior cranial base ratio (65.4%), linguoversion of the maxillary incisors (76.9%), and linguoversion of the mandibular incisors (80.8%). Incomplete cleft palate (CP) of hard palate with complete CP of soft palate (61.5%) was the most frequently observed, followed by complete CP of hard and soft palate (19.2%) and CP of soft palate (19.2%) (p < 0.05). However, CP severity did not show a significant correlation with any cephalometric variables except incisor mandibular plane angle (p < 0.05). Five craniofacial and 15 extra-craniofacial anomalies were observed (53.8% patients); this implicated the need of routine screening. Conclusions: The results might provide primary data for individualized diagnosis and treatment planning for pre-adolescent PRS patients despite a single institution-based data.

• 대한치과교정학회지
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• 제49권2호
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• pp.97-105
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• 2019

Objective: This study was performed to evaluate the accuracy and reliability of a newly designed method to achieve mandibular dental model superimposition, using voxel-based cone-beam computed tomography (CBCT) registration. Methods: Fourteen dry cadaveric mandibles and six teeth extracted from patients with severe periodontitis were used to establish 14 orthodontic tooth-movement models. The protocol consisted of two steps: in the first step, voxel-based CBCT mandible superimposition was performed; the reference comprised the external portion of the symphysis, extending to the first molar. The laser-scanned dental model image was then integrated with the CBCT image to achieve mandibular dental model superimposition. The entire process required approximately 10 minutes. Six landmarks were assigned to the teeth to measure tooth displacement, using tooth displacement on the superimposed laser-scanned mandibles as the reference standard. Accuracy was evaluated by comparing differences in tooth displacement based on the method and the reference standard. Two observers performed superimposition to evaluate reliability. Results: For three-dimensional tooth displacements, the differences between the method and the reference standard were not significant in the molar, premolar, or incisor groups (p > 0.05). The intraclass correlation coefficients for the inter- and intra-observer reliabilities of all measurements were > 0.92. Conclusions: Our method of mandibular dental model superimposition based on voxel registration is accurate, reliable, and can be performed within a reasonable period of time in vitro, demonstrating a potential for use in orthodontic patients.

• 치위생과학회지
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• 제23권4호
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• pp.245-254
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• 2023

Background: This study aimed to determine the skeletal and dental effects in pediatric and adolescent Korean patients with Class II Division 1 malocclusion treated using the Invisalign Mandibular Advancement (MA^®) appliance. Methods: The study included patients aged 6 to 18 years who received orthodontic treatment with the MA^® appliance for Class II Division 1 malocclusion at the Department of Pediatric Dentistry, Wonkwnag University Daejeon Dental Hospital, between July 1, 2018, and December 31, 2021. The treatment group consisted of 20 patients, 10 boys and 10 girls. The control participants were also 10 boys and 10 girls. Lateral cephalometric radiographs were taken before and after treatment, and 41 measurements of skeletal and dental changes were measured and analyzed using the V-Ceph^TM 8.0 (Osstem Implant). All analyses were performed using SPSS software (IBM SPSS for Windows, ver 26.0; IBM Corp.), and statistical significance was tested using paired and independent samples t-tests for within-group and between-group comparisons, respectively. Results: The patients in the treatment group showed significant decreases in ANB (A point, Nasion, B point), maxillary protrusion, maxillary anterior incisor labial inclination, and maxillary protrusion after treatment. However, when compared with the growth changes observed in the control group, only ANB and maxillary protrusion decreased, with no significant differences in SNA, SNB, and mandibular length. Conclusion: Collectively, the results of this study confirm that the use of MA^® appliance in pediatric and adolescent Korean patients with Class II Division 1 malocclusion results in a reduction of anteroposterior skeletal and dental disharmony.

• The Journal of Advanced Prosthodontics
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• 제15권6호
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• pp.281-289
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• 2023

PURPOSE. This study aimed to predict the positional coordinates of incisor points from the scan data of conventional complete dentures and verify their accuracy. MATERIALS AND METHODS. The standard triangulated language (STL) data of the scanned 100 pairs of complete upper and lower dentures were imported into the computer-aided design software from which the position coordinates of the points corresponding to each landmark of the jaw were obtained. The x, y, and z coordinates of the incisor point (X_P, Y_P, and Z_P) were obtained from the maxillary and mandibular landmark coordinates using regression or calculation formulas, and the accuracy was verified to determine the deviation between the measured and predicted coordinate values. Y_P was obtained in two ways using the hamularincisive-papilla plane (HIP) and facial measurements. Multiple regression analysis was used to predict Z_P. The root mean squared error (RMSE) values were used to verify the accuracy of the X_P and Y_P. The RMSE value was obtained after crossvalidation using the remaining 30 cases of denture STL data to verify the accuracy of Z_P. RESULTS. The RMSE was 2.22 for predicting X_P. When predicting Y_P, the RMSE of the method using the HIP plane and facial measurements was 3.18 and 0.73, respectively. Cross-validation revealed the RMSE to be 1.53. CONCLUSION. Y_P and Z_P could be predicted from anatomical landmarks of the maxillary and mandibular edentulous jaw, suggesting that Y_P could be predicted with better accuracy with the addition of the position of the lower border of the upper lip.

• 치과방사선
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• 제21권2호
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• pp.393-403
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• 1991

The purpose of this study was to evaluate the incidence and radiographic features of 1,300 cases of supernumerary teeth by means of the analysis of periapical radiograms and/or pantomograms in 69,442 persons visited the Department of Oral Radiology, School of Dentistry, Kyung Hee University during January 1980 to December 1989. This study of supernumerary teeth revealed the following features: 1. The incidence of supernumerary tooth was revealed to be 1.5% in total examined persons, and there was a higher incidence in males (74.0%) than in females (26.0%). 2. The supernumerary teeth were most frequently occurred in the 1 st decade (42.7%), followed by the 2nd decades (20.2%), the 3rd decades (14.1 %), and the 5th decades (7.2%). 3. There was a higher incidence in the maxilla (98.7%) than in the mandible (1.3%), and mesiodens (90.1 %) was the most frequently occurred. The maxillary lateral incisor region (3.1%) was next in order of frequency followed by maxillary distomolar (2.2%), and maxillary paramolar (1.5%). 4. There was a higher incidence of the impaction (82.7%) than that of the eruption (17.3%), and supernumerary tooth in lateral incisor region (87.8%) was the most frequently impacted one. 5. The inverted impaction was occurred in 63.1%, the vertical impaction in 18.1%, and the angulated impaction in 18.8%. In localization, a palatally (lingually) impacted supernumerary tooth was occurred in 85.0%, and middle impacted and buccally (labially) impacted supernumerary tooth showed the same incidence (7.5%). 6. A supplemental tooth was occurred in 3.2%, an accessory tooth in 96.8%, and a supplemental tooth was the most frequently occurred in maxillary lateral incisor and mandibular premolar region. 7. In effects of supernumerary tooth on adjacent tooth, crowding was occurred in 0.4%, diastema in 10.6%, rotation in 5.4%, eruption disturbance in 4.5%, root resorption in 2.5%, and dentigerous cyst in 2.2%.

• 대한소아치과학회지
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• 제31권1호
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• pp.52-58
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• 2004

과잉치는 유치열에서 0.3-0.8%, 영구치열에서 1.0-3.5% 정도로 발생하며, 2:1로 남자에게 호발 9:1로 상악에서 호발한다. 그 중 하악 전치부에서 발생하는 빈도는 전체 과잉치중에서 2-4%의 매우 낮은 빈도를 보인다고 보고되었다. 과잉치가 계속 존재할 경우 나타날 수 있는 합병증으로서 치간이개, 인접한 정상치아의 맹출장애, 치관의 형성이상, 인접치의 치근흡수, 함치성 낭종 등을 들 수 있으며, 치열 발육 중인 어린이의 경우 성장 중임을 감안하여 바람직한 교합유도를 위한 정확한 진단과 함께 적절한 처치가 필요하다. 본 증례는 전북대학교병원 소아치과에 내원한 6세 환아의 하악 전치부에서 발견된 양측성 매복 과잉치로서 그 중 한개는 영구치와 융합된 경우를 보고하는 바이다.

• 구강회복응용과학지
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• 제30권3호
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• pp.223-230
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• 2014

목적: 하악 절치 발치 치료를 받은 환자들의 치료로 인한 향상과 유지기간 후의 안정성을 평가하는 것이다. 연구 재료 및 방법: 하악 절치를 발치한 환자 총 20명을 대상으로 치료 전, 치료 직후, 2년의 유지기간 후의 모형 및 파노라마 방사선 사진을 분석하였다. Irregularity index, overjet, overbite, 치아 크기와 악궁 길이의 차이, 견치간 폭경, 제1 대구치간 폭경 및 미국교정학회에서 제시한 방법(ABO-CRE)을 평가하였다. 통계분석은 Wilcoxon signed-rank test를 이용하였다. 결과: 치료 전후 irregularity index가 유의하게 감소되었고(P = 0.000), 치아 크기와 악궁 길이의 차이는 유의하게 증가 하였다(P = 0.028). 유지기간 동안에 irregularity index는 유의하게 악화 되었다(P = 0.001). ABO-CRE 전체값의 변화는 치료 전후에 유의한 감소를 보이고(P = 0.000), 유지 전후에는 유의한 차이를 보이지 않았다(P = 0.053). 결론: 모형과 파노라마 방사선 사진을 이용하여 치료의 안정성 평가 결과, 하악 절치 발치 치료는 2년간의 유지기간 동안 치료 결과가 안정적으로 유지되었다고 할 수 있다.

• 대한소아치과학회지
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• 제26권4호
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• pp.630-635
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• 1999

치아의 전위는 매우 드문 치아 기형의 하나로서 발생 또는 맹출중 인접한 2개의 영구치의 위치가 서로 바뀐것을 말한다. 전위는 상악과 하악 모두에서 발생 가능한데 그중에서 상악에서의 발생이 더 흔하며 상악견치는 가장 호발하는 치아이다. 상악에서는 상악 견치와 제 1 소구치와의 전위가 가장 빈도가 높고 그 다음으로 상악 견치와 측절치와의 전위가 많다. 전위는 완전 전위와 불완전 전위로 나눌수 있는데 완전 전위는 치관뿐 아니라 치근의 위치까지 전위된 경우를 말하고 불완전 전위는 치근의 위치는 정상이고 치관만 전위된 경우이다. 전위의 원인에 대하여 명확하게 밝혀진 것은 없으나 유치의 만기잔존이나 조기상실, 발생중의 전위나 정상 맹출 경로로부터의 이탈, 유치열시기의 안면외상 등이 제기되고 있고 이밖에 과잉치, odontoma 또는 odontogenic cyst, 염증성 병소 등을 그 원인으로 생각해 볼 수 있다. 본 증례는 유치열시기의 안면외상으로 인하여 상악 영구 견치와 측절치의 전위가 발생한 경우로서 치료후 전위된 위치로의 양호한 배열을 이루었다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제27권4호
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• pp.350-359
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• 2005

Sagittal split ramus osteotomy(SSRO) has been commonly performed in the mandibular prognathism. The previous studies of the mandibular anatomy for SSRO have mostly been used in dry skull without consideration of age, sex or jaw relationship of patients. This study was performed to evaluate the location of mandibular canal and the anatomy of ramus, such as the location of mandibular lingula and the ramal bone marrow, which were associated with SSRO procedures, in the patients with mandibular prognathism and normal young adults by using computerized tomographs(CT) and 3D images. The young adults at their twenties, who were considered to complete their skeletal growth, and seen in the Department of Orthodontics and Oral and Maxillofacial Surgery in Chonnam National University Hospital between March 2000 and May 2003, were selected. This study was performed in 30 patients (15men, 15women) who were diagnosed as skeletal class I normal relationship, and another 30 patients (15men, 15women) who were diagnosed as skeletal class III relationship upon clinical examination and lateral cephalometric radiographs. The patients were divided into 2 groups : Class I group, the patients who had skeletal class Ⅰ normal relationship(n=30, 15men, 15women), and Class III group, the patients who had skeletal class III relationship(n=30, 15men, 15women). Facial CT was taken in all patients, and pure 3D mandibular model was constructed by V-works version 4.0. The occlusal plane was designed by three points, such as the mesiobuccal cusp of both mandibular 1st molar and the incisal edge of the right mandibular central incisor, and used as a reference plane. Distances between the tip of mandibular lingula and the occlusal plane, the sigmoid notch, the anterior and the posterior borders of ramus were measured. The height of ramal bone marrow from the occlusal plane and the distance between mid-point of mandibular canal and the buccal or lingual cortex of the mandible in the 1st and 2nd molars were measured by V-works version 4.0. Distance(Li-OP) between the occlusal plane and the tip of mandibular lingula of Class III Group was longer than that of Class I Group in men(p<0.01), but there was no significant difference in women between both groups. Distance(Li-SN) between the sigmoid notch and the tip of mandibular ligula of Class III group was longer than that of Class I Group in men(p<0.05), but there was no significant difference in women between both groups. Distance(Li-RA) between the anterior border of ramus and the tip of mandibular lingula of Class III Group was shorter than that of Class I Group in men and women(p<0.01). Distance(Li-RP) between the posterior border of ramus and the tip of mandibular lingula of Class III Group was slightly shorter than that of Class I Group in men(p<0.05), but there was no significant difference in women between both groups. Distance(RA-RP) between the anterior and the posterior borders of ramus of Class III Group was shorter than that of Class I Group in men and women(p<0.01). Longer the distance(SN-AN) between the sigmoid notch and the antegonial notch was, longer the vertical ramal length above occlusal plane, higher the location of mandibular lingula, and shorter the antero-posterior ramal length were observed(p<0.01). Height of ramal bone marrow of Class III Group was higher than that of Class I Group in men and women(p<0.01). Distance between mandibular canal and buccal cortex of Class III Group in 1st and 2nd lower molars was shorter than that of Class I Group in men and women (p<0.05 in 1st lower molar in men, p<0.01 in others). These results indicate that there are some anatomical differences between the normal occlusal patients and the mandibular prognathic patients, such as the anterior-posterior length of ramus, the height of ramal bone marrow, and the location of mandibular canal.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제26권3호
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• pp.293-296
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• 2000

The purpose of this study is to find the histopathological pattern of cysts. We reviewed the hospital chart, out-patient chart, roentgenogram, histopathologic report and operation report of 152 patients who had been diagnosed as cyst and treated at the department of Oral and Maxillofacial Surgery of Korea university hospital between Jan. 1, 1995 and Dec. 31, 1998. And then we studied clinically with regard to pathological classification, age and sex distribution, anatomical distribution and so on. The results were as follows : 1. In pathologic classification, radicular cyst (97cases, 64%), dentigerous cyst (35cases, 23%), odontogenic keratocyst (8cases, 5.3%) were dominant among cases of cyst. 2. The pattern of age distribution in cases of radicular cyst, dentigerous cyst and odontogenic keratocyst was similar to that found in previous studies. The peak incidence was in the second decade (27%) and third decade (29%) in overall cases. 3. The male-to-female ratio was 1.9 : 1. 4. Radicular cyst occured most frequently in the maxillary incisor teeth area, dentigerous cyst in mandibular wisdom teeth area, and odontogenic keratocyst in mandibular molar area.