• 대한치과교정학회지
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• 제47권6호
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• pp.344-352
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• 2017

Objective: The purpose of this study was to compare the changes induced in the pharyngeal airway space by orthodontic treatment with bodily retraction of the mandibular incisors and mandibular setback surgery without extraction. Methods: This retrospective study included 63 adult patients (32 men and 31 women). Thirty-three patients who had been treated via four-bicuspid extraction and bodily retraction of the mandibular incisors (incisor retraction, IR group) were compared with 30 patients who had been treated via mandibular setback surgery (MS group) without extraction. Lateral cephalograms were acquired and analyzed before (T1) and after treatment (T2). Results: The superior pharyngeal airway space did not change significantly in either group during treatment. The middle pharyngeal airway space decreased by $1.15{\pm}1.17mm$ and $1.25{\pm}1.35mm$ after treatment in the IR and MS groups, respectively, and the decrease was comparable between the two groups. In the MS group, the inferior pharyngeal airway space (E-IPW) decreased by $0.88{\pm}1.67mm$ after treatment (p < 0.01). The E-IPW was larger in the MS group than in IR group at T1, but it did not differ significantly between the two groups at T2. No significant correlation was observed between changes in the pharyngeal airway space and the skeletal and dental variables in each group. Conclusions: The middle pharyngeal airway space decreased because of the posterior displacement of the mandibular incisors and/or the mandibular body. The E-IPW decreased only in the MS group because of the posterior displacement of only the mandibular body.

• 대한치과교정학회지
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• 제29권2호
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• pp.209-217
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• 1999

하악 전돌자에서의 치은퇴축 발생 소인을 알아보기 위하여 20세 전후의 악교정수술을 요하는 하악전돌자와 비슷한 연령대의 정상교합자를 대상으로 측모 두부방사선 사진과 하악 전치부의 단층 촬영사진을 사용하여 순측 치조골 계측치를 비교 연구한 바 다음과 같은 결과를 얻었다. 1. 하악전돌자의 순측 치조골 피질판의 단면적은 정상군보다 의미있게 작았다. 2. 하악전돌자의 치조정은 정상군에 비하여 낮은 것으로 나타났다. 3. 순측 치조골판의 면적은 백아법랑질 경계에서 치조정까지의 거리와는 역상관관계를, 치조정에서 치근단까지의 거리와는 순상관관계를 보였다. 4. 하악전돌자에서 IMPA의 증가는 symphysis의 두께와 순상관 관계를, 치조골의 높이와는 역상관 관계를 보였다. 이상의 결과에서 골격성 하악전돌자는 변연부 순측 치조골이 정상교합자보다 작음으로 치은퇴축 발생 가능성이 큼을 시사하였다.

• 대한치과교정학회지
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• 제45권2호
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• pp.89-94
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• 2015

Objective: To test the null hypothesis that SmartClip self-ligating brackets are more effective than conventional brackets for initial mandibular alignment and identify influential factors. Methods: Fifty patients were randomly allocated to two equal treatment groups by using an online randomization program: self-ligating group (SmartClip brackets) and conventional group (Gemini brackets). The archwire sequence was standardized. Changes in anterior irregularity index, intercanine width, and intermolar width were assessed on plaster models at 8th and 16th weeks. Changes in incisor position and inclination were assessed on lateral cephalometric radiographs at 16 weeks. Intragroup and intergroup comparisons were performed with paired t-test and Student's t-test, respectively. Multiple linear regression was performed to identify variables affecting improvement in anterior ambiguity. Results: Data of 46 patients were analyzed; those missing an appointment (n = 2) or showing bracket breakage (n = 2) were excluded. Incisor inclination (p < 0.05), intercanine width (p < 0.05), and intermolar width (p > 0.05) increased at 8 and 16 weeks in both the groups; no significant intergroup differences were noted (p > 0.05). Initial anterior irregularity index and intercanine width change were significantly associated with improvement in anterior irregularity (p < 0.001). Conclusions: The null hypothesis was rejected. Bracket type has little effect on improvement in anterior ambiguity during initial mandibular alignment.

• 구강회복응용과학지
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• 제19권3호
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• pp.153-168
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• 2003

It is very important to arrange the artificial teeth correctly in bucco-lingual (labio- lingual) relation in reconstrcting dentition. Although many anatomic landmarks and techniques have been reported over the years, they are based on westerns. So this study was performd to examine the horizontal relations of mandibular teeth in Korean dentulous adults. 200 volunteers(mean age 22.9) who had natural dentition were selected. The impressions were taken with irreversible hydrocolloid impression material and mandibular study models were fabricated using class I dental stone. Then they were measured with 3-dimensional measuring device specially designed for this study. The results were as follows ; It is better to consider the lingual cusps of the lower posterior teeth as a guide than the linguoaxial surfaces of the lower posterior teeth, arranging the lower posterior teeth buccally to the line which starts from the mesial aspect of the lower canine and continue backward to the lingual aspect of the retromolar pad. It is better to arrange the fossae of the lower posterior teeth buccally to the line which starts from the cusp tip of the lower canine and continue backward to the top of the retromolar pad. The positions of the lower posterior teeth in the denture-bearing area ; considering the fossa as a guide, the 2nd premolar was positioned in center. considering the buccal cusp as a guide, the 1st molar and the 2nd molar were positioned in center. the distance ratio(d/a) was incresed constantly from the lower canine to the 2nd molar d ; the distance between the buccal vestibule(the lowest point) and the buccal cusp tips of the lower posterior teeth. a ; the distance between the buccal vestibule(the lowest point) and the lingual vestibule(the lowest point). The lower canine was positioned lingually($0.11{\pm}0.13$) than the labial vestibule, and the central incisor and the lateral incisor were positioned almost in the imaginary perpendicular plane of the labial vestibule(the lowest point).

• Journal of Dental Anesthesia and Pain Medicine
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• 제15권2호
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• pp.63-68
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• 2015

Background: Conventional anesthetic nerve block injections into the mandibular foramen risk causing nerve damage. This study aimed to compare the efficacy and safety of the anterior technique (AT) of inferior alveolar nerve block using felypressin-propitocaine with a conventional nerve block technique (CT) using epinephrine and lidocaine for anesthesia via the mandibular foramen. Methods: Forty healthy university students with no recent dental work were recruited as subjects and assigned to two groups: right side CT or right side AT. Anesthesia was evaluated in terms of success rate, duration of action, and injection pain. These parameters were assessed at the first incisor, premolar, and molar, 60 min after injection. Chi-square and unpaired t-tests were used for statistical comparisons, with a P value of < 0.05 designating significance. Results: The two nerve block techniques generated comparable success rates for the right mandible, with rates of 65% (CT) and 60% (AT) at both the first molar and premolar, and rates of 60% (CT) and 50% (AT) at the lateral incisor. The duration of anesthesia using the CT was $233{\pm}37min$, which was approximately 40 min shorter than using the AT. This difference was statistically significant (P < 0.05). Injection pain using the AT was rated as milder compared with the CT. This difference was also statistically significant (P < 0.05). Conclusions: The AT is no less successful than the CT for inducing anesthesia, and has the added benefits of a significantly longer duration of action and significantly less pain.

• 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.

• 대한치과교정학회지
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• 제48권4호
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• pp.224-235
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• 2018

Objective: The purpose of this study was to compare the skeletal, dental, and soft-tissue treatment effects of nonextraction therapy using the modified C-palatal plate (MCPP) to those of premolar extraction (PE) treatment in adult patients with Class II malocclusion. Methods: Pretreatment and posttreatment lateral cephalographs of 40 adult patients with Class II malocclusion were retrospectively analyzed. The MCPP group comprised 20 patients treated with total arch distalization of the maxillary arch while the PE group comprised 20 patients treated with four PE. Fifty-eight linear and angular measurements were analyzed to assess the changes before and after treatment. Descriptive statistics, paired t-test, and multivariate analysis of variance were performed to evaluate the treatment effects within and between the two groups. Results: The MCPP group presented 3.4 mm of retraction, 1.0 mm of extrusion, and $7.3^{\circ}$ lingual inclination of the maxillary central incisor. In comparison, the PE group displayed greater amount of maxillary central incisor retraction and retroclination, mandibular incisor retraction, and upper lip retraction (5.3 mm, $14.8^{\circ}$, 5.1 mm, and 2.0 mm, respectively; p < 0.001 for all). In addition, the MCPP group showed 4.0 mm of distalization and 1.3 mm of intrusion with $2.9^{\circ}$ distal tipping of the maxillary first molars. Conclusions: These findings suggest the MCPP is an effective distalization appliance in the maxillary arch. The amount of incisor retraction, however, was significantly higher in the PE group. Therefore, four PE may be recommended when greater improvement of incisor position and soft-tissue profile is required.

• 대한치과교정학회지
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• 제50권3호
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• pp.216-226
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• 2020

Root resorption can be caused by several factors, including contact with the cortical bone. Here we report a case involving a 21-year-old female with Angle Class II, division 1 malocclusion who exhibited significant root resorption in the maxillary right central incisor after orthodontic treatment. The patient presented with significant left-sided deviation of the maxillary incisors due to lingual dislocation of the left lateral incisor and a Class II molar relationship. Cephalometric analysis demonstrated a Class I skeletal relationship (A point-nasion-B point, 2.5°) and proclined maxillary anterior teeth (upper incisor to sella-nasion plane angle, 113.4°). The primary treatment objectives were the achievement of stable occlusion with midline agreement between the maxillary and mandibular dentitions and appropriate maxillary anterior tooth axes and molar relationship. A panoramic radiograph obtained after active treatment showed significant root resorption in the maxillary right central incisor; therefore, we performed cone-beam computed tomography, which confirmed root resorption along the cortical bone around the incisive canal. The findings from this case, where different degrees of root resorption were observed despite comparable degrees of orthodontic movement in the bilateral maxillary central incisors, suggest that the incisive canal could be an inducing factor for root resorption. However, further investigation is necessary to confirm this assumption.

• Imaging Science in Dentistry
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• 제50권1호
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• pp.9-14
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• 2020

Purpose: The purpose of this study was to evaluate vertical bone loss and alveolar bone thickness in the maxillary and mandibular incisors of patients with skeletal class III malocclusion. This study also aimed to evaluate the periodontal condition of class III malocclusion patients who had not undergone orthodontic treatment. Materials and Methods: The sample included cone-beam computed tomography scans of 24 Korean subjects (3 male and 21 female). Alveolar bone thickness (ABT), alveolar bone area (ABA), alveolar bone loss (ABL), and fenestration of the maxillary and mandibular incisors were measured using 3-dimensional imaging software. Results: All incisors displayed an ABT of less than 1.0 mm from the labial surface to root level 7 (70% of the root length). A statistically significant difference was observed between the mandibular labial and lingual ABAs and between the maxillary labial and mandibular labial ABAs. The lingual ABA of the mandibular lateral incisors was larger than that of the mandibular central incisors. ABL was severe on the labial surface. A statistically significant difference was observed between the maxillary and mandibular labial ABL values(21.8% and 34.4%, respectively). Mandibular lingual ABL (27.6%) was significantly more severe than maxillary lingual ABL (18.3%) (P<0.05). Eighty-two fenestrations were found on the labial surfaces of the incisors, while only 2 fenestrations were observed on the lingual surfaces. Fenestrations were most commonly observed at root level 6. Conclusion: Careful evaluation is needed before orthodontic treatment to avoid iatrogenic damage of periodontal support when treating patients with class III malocclusion.

• 구강회복응용과학지
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• 제30권3호
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• pp.215-222
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• 2014

본 연구는 수평적, 수직적 안면 골격 유형에 따른 하악 전치부 치조골의 형태학적 차이를 알아보기 위하여 시행 하였다. 연구 재료 및 방법: 40명의 Cone-beam computed tomography (Cone-beam CT)를 선별하여, 4개 군으로 분류하였다. Cone-beam CT 자료를 이용하여 하악 전치부 치조골의 부피($mm^3$), 하악 4절치 치축 기준 시상단면의 단면적(총 단면적, 해면골 단면적: $mm^2$), 백악법랑경계(cemento-enamel junction: CEJ) 2 mm, 3 mm 아래 순, 설측 치조골 두께를 측정하였다. 통계분석은 GLM, Kruskal-Wallis test and Tukey HSD를 사용하였다. 결과: 측절치의 백악법랑경계 2 mm, 3 mm 하방 설측 치조골 두께가, Class I low angle군이 나머지 3군 보다 두꺼웠다 (P < 0.05). 하악 전치 치조골의 부피, 전체 치조골 및 해면골의 단면에서의 통계적으로 유의한 차이는 없었다. 결론: Class I low angle군은 Class II high angle군에 비해 하악 전치 치조골의 설측 부위가 더 두껍다.