• 대한치과교정학회지
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• 제47권1호
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• pp.39-49
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• 2017

Objective: This retrospective, cross-sectional study aimed to establish reference data for normal crown and root lengths and the root-crown ratios (R/C ratios) for the mature maxillary and mandibular incisors in a Korean population by using cone-beam computed tomography (CBCT). Methods: We included 672 Korean patients (141 men and 531 women; mean age, $27.2{\pm}7.7years$) who underwent CBCT examinations during various dental treatments. Crown and root lengths and the R/C ratios of the maxillary and mandibular incisors were measured using CBCT data, which were analyzed to detect significant differences between demographic factors as well as sagittal and vertical skeletal or occlusal relationships. Results: Teeth of the same type in each half-arch were symmetrical. The mean R/C ratios varied from 1.1 to 1.2 for the maxillary incisors and from 1.3 to 1.4 for the mandibular incisors. Crown and root lengths were greater in men than in women, regardless of tooth type. Root lengths and R/C ratios for the mandibular incisors were significantly greater in patients with skeletal Class II malocclusion or an excessive overjet than in the other patients. The R/C ratios for the mandibular incisors were lower in patients with an open bite than in those with a normal or deep bite. Moreover, the R/C ratios for the mandibular incisors increased with age. Conclusions: The data obtained in our study can serve as reference values for crown and root lengths and the R/C ratios for the maxillary and mandibular incisors in the Korean population.

• 대한치과보철학회지
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• 제56권1호
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• pp.88-94
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• 2018

최근 치과치료의 영역에서 디지털 임플란트 시스템은 그 영역을 넓혀 나가고 있다. 디지털 장비들의 기술적 발전에 힘입어 한계점들이 하나 둘씩 극복되었다. 초기 단일치아 수복 정도에나 사용되었던 디지털 임플란트 시스템은 임플란트 수술에서부터 보철물 제작까지 무치악의 영역에서도 사용되고 있다. 본 증례에서는 50세의 하악 무치악 환자가 임플란트를 이용한 교합 재건을 원하였다. 하악의 임플란트 수복을 위해서 "All-on-4" 개념의 디지털 임플란트 시스템 사용을 계획하였고, 무절개 수술을 위한 가이드 장치를 제작하여 수술을 시행하였다. 수술 후, 전악 보철을 디지털 장비를 이용하여 제작하였다. 전체 치료 과정에서 기존의 아날로그 방식(인상채득, 납형 제작, 주조 등)을 가능한 배제하고 디지털 시스템을 이용하여 기공과정 및 임상과정을 최소화하기로 계획하였고 만족할만한 결과를 얻었기에 보고하는 바이다.

• 구강회복응용과학지
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• 제17권4호
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• pp.275-282
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• 2001

Centric relation is defined the horizontal position between maxilla and mandible when condylar head of mandible is positioned adequately in mandibular fossa. The most recent concept of centric relation position is defined as the mandibular position in which the condyles are in their most superoanterior position in the articular fossa, resting against the posterior slope of the articular eminences, with the articular disk properly interposed. To be suitable as a reference point during occlusal management, a mandibular position of centric relation has to be functionally acceptable to the patient and clinically reproducible and achievable during everyday practice. There are numerous methods for determination of centric relation, and in this study we used three of them, Gothic arch tracing(Group I), leaf gauge(Group II), and anterior jig(Group III). The subjects were 10, 8 men and 2 women, age-ranged from 23 to 26 years old, had no prosthetics in thier mouth, and had no sign and symptom of temporomandibular disorders. We gained three occlusal records using each method, and then the degree of the reproducibility was examined with split cast technique. In this study the reproducibility of centric relation using split cast technique was greater in the order of Group I(mean 1.6), Group II(mean 1.4), and Group III(mean 1.3), but there was no significant differences among them statistically(p>0.05).

• Journal of Oral Medicine and Pain
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• 제21권1호
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• pp.197-206
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• 1996

This study ws performed to investigate the relationship between cervical curvature and the spatial position of the posterior part of the atlas imaged in the lateral cephalograph. Sixty six patients with temporomandibular disorders(TMD) and twenty dental students were selected for patients group and control group, respectively. The average age of patients group was 26.3 years, and 24.9 years in control group. Measured variables were cervical depth, upper space between the atlas and the base of the occiput, lower space between the atlas and the spinous process of the axis, rea of the posterior part of the atlas imaged in the lateral cephalograph, and the cervical curvature passing through the uppermost point in dorsal side of Dens of the Axis to the lowermost and rearmost point of the 5th cervical vertebra. The reliability of the method used for measuring cervical curvature with curved ruler was also tested. The results obtained were as follows : 1. Cervical depth of patients group was 122.9mm and significantly shorter than that of control group, in which cervical depth was 131.9mm, and cervical depth was significantly correlated with other variables in all subjects. 2. Upper space was greater in patients group, but total space including upper and lower space showed no difference between the two groups. The average value of total space was 26.5mm. 3. Area of the posterior part of the atlas was 168.2$\textrm{mm}^2$ in patients group, and 186.5$\textrm{mm}^2$ in control group with significant difference between the two groups. 4. Average range of radius of cervical curvature were 33-40cm and there was no difference between the two groups. 5. There was no significant correlation between the cervical curvature and the area of the posterior arch of the atlas. 6. The method using curved ruler for measuring cervical curvature could be accepted as a reliable method.

• 대한치과교정학회지
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• 제17권1호
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• pp.93-106
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• 1987

The purpose of this study was to investigate the fittness of Golden relation items was advocated by Ricketts whether or not it is applicable to the young adult Korean dentitions and also to evaluate the several new Golden relation items conducted by the author. The material was consisted of 81 dental casts (34 male, 47 female) with ideal occlusion, which never undergone orthodontic, prosthodontic procedures. Measurements were made on the arch dimensions using sliding caliper (Mitutoyo. Co) and data were computerized and analyzed. The findings of this study were as follows, 1. The Golden proportion advocated by Ricketts dose not seem to directly applicable to the Korean normal dentition, however, the modification from the Ricketts' original shows the Golden proportion as follow: A first series of progressive Golden relations was found on the Golden ratio among the lower central incisors width, the inter mesioincisal width of the upper lateral incisors, and the upper first premolars width. A second series was found on the Golden ratio among the lower lateral incisors width, lower inter canine tips width and theupper first molar distal cusp tips width. A third series was found on the Golden ratio between the inter distal aspect width of e lower canine and the mesial cusp tips width of the lower second molars or inter cusp tips width of upper second premolars. 2. In addition to Ricketts' original, 4 new Golden proportions were found in young adult Korean dentition, these are as follows; The tips of lower canine width had Golden relation with the width of the upper first premolar buccal cusp tips or the width of the lower first molar central fossae. The distal aspect of the lower first premolars had Golden relation with the buccal surface widths of the lower or upper second molars. The width of upper lateral incisors had Golden relation with the upper second molar height. The width of the lower canine tips had Golden relation with the lower second molar height.

• 대한치과교정학회지
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• 제47권2호
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• pp.77-86
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• 2017

Objective: The aim of this study was to evaluate the skeletal and dentoalveolar changes after miniscrew-assisted rapid palatal expansion (MARPE) in young adults by cone-beam computed tomography (CBCT). Methods: This retrospective study included 14 patients (mean age, 20.1 years; range, 16-26 years) with maxillary transverse deficiency treated with MARPE. Skeletal and dentoalveolar changes were evaluated using CBCT images acquired before and after expansion. Statistical analyses were performed using paired t-test or Wilcoxon signed-rank test according to normality of the data. Results: The midpalatal suture was separated, and the maxilla exhibited statistically significant lateral movement (p < 0.05) after MARPE. Some of the landmarks had shifted forwards or upwards by a clinically irrelevant distance of less than 1 mm. The amount of expansion decreased in the superior direction, with values of 5.5, 3.2, 2.0, and 0.8 mm at the crown, cementoenamel junction, maxillary basal bone, and zygomatic arch levels, respectively (p < 0.05). The buccal bone thickness and height of the alveolar crest had decreased by 0.6-1.1 mm and 1.7-2.2 mm, respectively, with the premolars and molars exhibiting buccal tipping of $1.1^{\circ}-2.9^{\circ}$. Conclusions: Our results indicate that MARPE is an effective method for the correction of maxillary transverse deficiency without surgery in young adults.

• Journal of Oral Medicine and Pain
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• 제23권2호
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• pp.143-155
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• 1998

This study was performed to investigate the factor that might affect mandibualr body rotation. For the study, 115 patients with temporomandibular disorders and 35 dental students without angy signs and symptoms of temporomandibular disorders were randomly selected as the patient group and the contreol group, respectively. Preferred chewing side, Angle' classification, lateral guidance pattern, and affected side were clinically recorded, and the amount of Mandibular body rotational torque movement was measured in wide opening and closure, in right and left excursion with vertical and lateral distance in frontal plane, right and left rotational angel in horizontal and in frontal plane. Masticatory muscle activity of anteriorocclusal contact pattern on maximal hard biting were also observed synchronously with BioEMG and T-Scan , respectively. The observed items were muscle activity of anterior temporalis and superficial masseter, and tooth contact status related to contact number, force, duration, and occlusal unbalance between right and left arch. The data collected were analyzed by SAS statistical program. The results of this study were as follows : 1. Mean value of vertical distance in frontal plane in wide opening and closure was more in control subjects than in patients, but there was no difference for rotational angle. In right excursion, rotational angles were greater in patient group than in control group. 2. Comparison among the subjects by preferred chewing side did not reveal any significant difference, but comparison among patients by affected side showed more rotational amount in bilaterally affected patients than in unilaterally affected patients. 3. Comparison among the subjects by Angle's classification or lateral guidance pattern revealed no difference. There was also no difference between preferred chewing side and contralateral side, and between affected side and contralateral side. 4. Positive correlation in madibular rotational torque movements were observed among vertical distance, total horizontal rotation angle, electromyographic activity of anterior temporalis, tooth contact number, and tooth contact force but total frontal rotation angle almost did not show any correlation with other variables except vertical distance.

• 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.

• The Journal of Advanced Prosthodontics
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• 제1권3호
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• pp.118-123
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• 2009

STATEMENT OF PROBLEM. Proper proximal contact is important for maintaining and stabilizing the dental arch. However, the proximal contact strength (PCS) is not a constant value and can be affected by a variety of factors. PURPOSE. This study examined the influences of postural changes on the posterior PCS. MATERIAL AND METHODS. Twelve adults with a normal occlusion and had not undergone prosthetic treatment or proximal restoration were participated in this study. A metal strip was inserted into the proximal surface and removed at a constant velocity. The contact strength was measured in every contact point between canine to second molar in both arches. The PCSs were obtained initially in the upright position, secondly in the supine position and finally in the upright position again. All measurements were repeated after a 2 hour period. Statistical analysis was carried out using the Friedman test (P < .05). RESULTS. Generally, a decrease in PCS occurred when the posture was changed from the initial upright to supine position, while it increased when the posture was changed from the supine to upright position. A significant change was observed in all areas except for between the canine-first premolar in the maxilla and between the first molar-second molar in the mandible areas. CONCLUSION. The posterior PCS, which dentists generally believe to be a static feature of occlusion, is affected significantly by posture.

• 대한치과교정학회지
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• 제50권5호
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• pp.304-313
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• 2020

Objective: The aim of this study was to evaluate the stability of bimaxillary surgery involving bilateral intraoral vertical ramus osteotomy performed with or without presurgical miniscrew-assisted rapid palatal expansion (MARPE) in adult patients with skeletal Class III malocclusion. Methods: A total of 40 adult patients with skeletal Class III malocclusion were retrospectively divided into two groups (n = 20 each) according to the use of MARPE for the correction of transverse maxillomandibular discrepancy during presurgical orthodontic treatment. Serial lateral cephalograms and dental casts were analyzed until 6 months after surgery. Results: Before presurgical orthodontic treatment, there was no significant differences in terms of sex and age between groups. However, the difference of approximately 3.1 mm in the maxillomandibular intermolar width was statistically significant (p < 0.001). Two days after surgery, the mandible had moved backward and upward without any significant intergroup difference. Six months after surgery, the maxillary intercanine (2.7 ± 2.1 mm), interpremolar (3.6 ± 2.4 mm), and intermolar (2.0 ± 1.3 mm) arch widths were significantly increased (p < 0.001) relative to the values before presurgical orthodontic treatment in the MARPE group; these widths were maintained or decreased in the control group. However, there was no significant difference in surgical changes and the postsurgical stability between the two groups. No significant correlations existed between the amount of maxillary expansion and postsurgical mandibular movement. Conclusions: MARPE is useful for stable and nonsurgical expansion of the maxilla in adult patients with skeletal Class III malocclusion who are scheduled for bimaxillary surgery.