• 대한치과교정학회지
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• 제50권5호
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• pp.314-323
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• 2020

Objective: To identify the available evidence on the effects of rapid maxillary expansion (RME) with three-dimensional imaging and provide meta-analytic data from studies assessing the outcomes using computed tomography. Methods: Eleven electronic databases were searched, and prospective case series were selected. Two authors screened all titles and abstracts and assessed full texts of the remaining articles. Seventeen case series were included in the quantitative synthesis. Seven outcomes were investigated: nasal cavity width, maxillary basal bone width, alveolar buccal crest width, alveolar palatal crest width, inter-molar crown width, inter-molar root apex width, and buccopalatal molar inclination. The outcomes were investigated at two-time points: post-expansion (2-6 weeks) and post-retention (4-8 months). Mean differences and 95% confidence intervals were used to summarize and combine the data. Results: All the investigated outcomes showed significant differences post-expansion (maxillary basal bone width, +2.46 mm; nasal cavity width, +1.95 mm; alveolar buccal crest width, +3.90 mm; alveolar palatal crest width, +3.09 mm; intermolar crown width, +5.69 mm; inter-molar root apex width, +2.85 mm; and dental tipping, +3.75°) and post-retention (maxillary basal bone width, +2.21 mm; nasal cavity width, +1.55 mm; alveolar buccal crest width, +3.57 mm; alveolar palatal crest width, +3.32 mm; inter-molar crown width, +5.43 mm; inter-molar root apex width, +4.75 mm; and dental tipping, 2.22°) compared to pre-expansion. Conclusions: After RME, skeletal expansion of the nasomaxillary complex was greater in most caudal structures. Maxillary basal bone showed 10% post-retention relapse. During retention period, uprighting of maxillary molars occurred.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제41권
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• pp.33.1-33.7
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• 2019

Background: The concept of the ideal morphology for the alveolar bone form is an important element to reconstruct or restore the in maximizing esthetic profile and functional alveolar bone restoration. The purpose of this preliminary study is to evaluate the normal alveolar bone structure to provide the standard reference and guide template for use in diagnosing for implant placement, determining the correct amount of bone augmentation in actual clinical practice and producing prostheses based on three-dimensional imaging assessment of alveolar bone. Methods: This study was included 11 men and 11 women (average age, 22.6 and 24.5 years, respectively) selected from among 127 patients. The horizontal widths of alveolar bone of maxilla and mandible were measured at the crestal, mid-root, and root apex level on MDCT (multi-detector computed tomography) images reconstructed by medical imaging software. In addition, tooth dimensions of the central incisors, canines, second premolars, and first molars of maxilla and mandible, including the horizontal width of the interdental alveolar bone crest, were also measured and statistically analyzed. Results: The horizontal alveolar bone width of the palatal side of maxilla showed a distinct increment from the alveolar bone crest to the apical region in both anterior and posterior areas. The average widths of the maxillary alveolar ridge were as follows: central incisor, 7.43 mm; canine, 8.91 mm; second premolar, 9.57 mm; and first molar, 12.38 mm. The average widths of the mandibular alveolar ridge were as follows: central incisor, 6.21 mm; canine, 8.55 mm; second premolar, 8.45 mm; and first molar, 10.02 mm. In the buccal side, the alveolar bone width was not increased from the crest to the apical region. The horizontal alveolar bone width of an apical and mandibular border region was thinner than at the mid-root level. Conclusions: The results of the preliminary study are useful as a clinical guideline when determining dental implant diameter and position. And also, these measurements can also be useful during the production of prefabricated membranes and customized alveolar bone scaffolds.

• 한국임상수의학회:학술대회논문집
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• 한국임상수의학회 2006년도 춘계학술대회
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• pp.210-210
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• 2006

• Imaging Science in Dentistry
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• 제48권3호
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• pp.191-199
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• 2018

Purpose: This study classified alveolar arch forms and evaluated differences in alveolar bone thickness among arch forms in the anterior esthetic region using cone-beam computed tomography (CBCT) images. Materials and Methods: Axial views of 113 CBCT images were assessed at the level of 3 mm below the cementoenamel junction (CEJ) of the right and left canines. The root center points of teeth in the anterior esthetic region were used as reference points. Arch forms were classified according to their transverse dimensions and the intercanine width-to-depth ratio. The buccolingual alveolar bone thickness of each tooth was measured at 3 mm below the CEJ and at the mid-root level. Differences in the mean thicknesses among arch forms were analyzed. Results: Anterior maxillary arches could be classified as long narrow, short medium, long medium, and long wide arches. Significant differences in buccolingual alveolar bone thickness among the arch groups were found at both levels. The long wide arches presented the greatest bone thickness, followed by the long medium arches, while the long narrow and short medium arches were the thinnest. Conclusion: Arch forms were classified as long narrow, short medium, long medium, and long wide. The buccolingual alveolar bone thickness exhibited significant differences among the arch forms.

• Imaging Science in Dentistry
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• 제50권3호
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• pp.217-226
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• 2020

Purpose: The purpose of this study was to analyze the quantity and quality of the mandibular anterior alveolar bone in terms of alveolar width, density, and total alveolar height (TAH) based on dental status, gender, and age. Additionally, this study aimed to quantitatively evaluate the available alveolar height for graft harvesting (AHGH) and examine its variability based on the aforementioned factors. Materials and Methods: This retrospective cone-beam computed tomographic study included a total of 100 subjects. On the basis of gender, dental status, and age, the scans were divided into 3 primary groups and 8 subgroups. The mandibular alveolar width and density were measured 5 mm mesial to the mental foramen bilaterally and at the midline. The TAH was measured at the midline, and the AHGH was measured as the midline distance between 5 mm apical to the root of the canines and 5 mm superior to the lower border. Results: The mandibular alveolar width was statistically similar between dentulous and edentulous patients (P>0.05). A significantly greater density was observed at the midline in edentulous patients (P<0.05). The TAH was significantly greater in edentulous male patients than in edentulous female patients (P<0.05). Dentulous and male patients had significantly greater AHGH than edentulous and female patients, respectively (P<0.05). Conclusion: Based on the data evaluated in this study, it can be concluded that the mandibular symphyseal area has adequate bone quality and quantity for bone graft harvesting for dental implant therapy.

• 대한치과교정학회지
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• 제48권2호
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• pp.98-106
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• 2018

Objective: This study aimed to explore the usefulness of adjunctive buccal and palatal corticotomy for adult maxillary expansion in an animal model using cone-beam computed tomography (CBCT). Methods: Twelve adult sheep were randomly divided into two groups (each n = 6): a control group, where no treatment was administered, and a treatment group, where buccal and palatal corticotomy-assisted maxillary expansion was performed. CBCT scans were taken before (T1) and after (T2) treatment. Differences in all transverse dental and alveolar dimensions, alveolar width at crest level, hard palate level, horizontal bone loss, interdental cusp width and inter-root apex were assessed using Wilcoxon signed-rank and Mann-Whitney U-tests. Kruskal-Wallis tests and pairwise comparisons were used to detect the significance of differences among the inter-premolar and inter-molar widths. Results: CBCT data revealed significant changes in all transverse dental and alveolar dimensions. The mean interpremolar alveolar width showed an increase of 2.29 to 3.62 mm at the hard palate level, 3.89 to 4.38 mm at the alveolar crest level, and 9.17 to 10.42 mm at the buccal cusp level. Dental changes in the vertical dimension were not significant. Conclusions: Our findings based on an adult animal model suggest that adjunctive buccal and palatal corticotomy can allow for both skeletal and dental expansion, with the amount of dental expansion exceeding that of skeletal expansion at alveolar crest and hard palate levels by two and three folds, respectively. Therefore, this treatment modality is potential to enhance the outcomes of maxillary expansion in adults.

• Restorative Dentistry and Endodontics
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• 제38권2호
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• pp.59-64
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• 2013

Apical surgery cuts off the apical root and the crown-to-root ratio becomes unfavorable. Crown-to-root ratio has been applied to periodontally compromised teeth. Apical root resection is a different matter from periodontal bone loss. The purpose of this paper is to review the validity of crown-to-root ratio in the apically resected teeth. Most roots have conical shape and the root surface area of coronal part is wider than apical part of the same length. Therefore loss of alveolar bone support from apical resection is much less than its linear length.The maximum stress from mastication concentrates on the cervical area and the minimum stress was found on the apical 1/3 area. Therefore apical root resection is not so harmful as periodontal bone loss. Osteotomy for apical resection reduces longitudinal width of the buccal bone and increases the risk of endo-perio communication which leads to failure. Endodontic microsurgery is able to realize 0 degree or shallow bevel and precise length of root resection, and minimize the longitudinal width of osteotomy. The crown-to-root ratio is not valid in evaluating the prosthodontic prognosis of the apically resected teeth. Accurate execution of endodontic microsurgery to preserve the buccal bone is essential to avoid endo-perio communication.

• 대한치과교정학회지
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• 제37권3호
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• pp.220-230
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• 2007

골격성 I급이면서 수직적으로 정상인 환자 160명(남자 80명, 여자 80명)의 측모 두부방사선 계측사진을 대상으로 하악 전치부 치조골의 협설측 두께를 치축을 기준으로 계측하여 연령에 따른 차이를 조사하여 다음과 같은 결과를 얻었다. 하악전치부 치조골의 협설측 두께와 하악 전치부 설측 치조골의 두께는 연령이 증가함에 따라 여자의 CEJ 하방 2 mm 부위를 제외하고는 남녀 모두에서 유의한 감소를 보였다. 반면에, 하악 전치부 협측 치조골의 두께와 하악 이부 최대 풍융부의 두께는 연령이 증가함에 따라 유의한 차이를 보이지 않았다. 이상의 연구를 통하여 한국인에 있어서 수평적으로 I급의 골격형태이면서 수직적으로 정상인 환자에서는 성인보다는 성장기환자에서 하악 전치의 설측 치조골의 두께가 더 두꺼워 발치치료에서와 같은 하악 전치의 설측이동이 유리할 것으로 사료된다.

• Journal of Periodontal and Implant Science
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• 제34권2호
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• pp.281-292
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• 2004

Periodontal defects of the furcation are characterized by several inherent anatomic factors that can make successful periodontal therapy difficult and results unpredictable. The severity and rate of occurrence of periodontal disease are directly related to the location of the furcation relative to the cementa-enamel junction and anatomical form of the root by limiting the accessibility and effectiveness of the periodontal instrumentation. This study investigated the reliability and accuracy of panoramic radiograph diagnoses of the periodontal state of mandibular molars, particularly regarding the diagnosis of furcation area periodontal defects, treatment planning, and prognosis prediction. This study examined a total of 110 teeth belonging to 33 subjects (19 male, 14 female) presenting with incipient to moderate periodontitis 4-7mmpocket depth. The alveolar bone level, length and width of the root trunk, and root separation angle were measured using the panoramic radiograph and compared to the results taken directly by retracting a full-thickness flap. The results of the study are as follows: 1. Data regarding the alveolar bone level of the mandibular first molar showed that the directly taken surgical measurements resulted in $5.1{\pm}0.9mm$ that was slightly deeper than the corresponding panoramic measurement resulted in $4.8{\pm}0.8mm$, but these differences were statistically insignificant (p>0.05). 2. The data of the directly taken surgical measurement of the mandibular second molar $(5.1{\pm}1.1mm)$ was slightly deeper than the corresponding panoramic measurement $(4.7{\pm}1.2mm)$, but these differences were statistically insignificant (p>0.05). 3. The measured values of the length and width of the mandibular first molar root trunks were determined to be $4.1{\pm}0.6mm$ and $7.3{\pm}0.9mm$, respectively, while the values of the mandibular second molar root trunks were determined to be $4.6{\pm}1.3mm$ and $7.6{\pm}0.9mm$ respectively. The differences between these values were found to be statistically significant (p<0.01). 4. The measured values of the root separation angle showed that the mandibular first molars averaged $34.5{\pm}4.4^{\circ}$, while the mandibular second molars averaged $23.0{\pm}10.0^{\circ}$. The differences between these values were found to be statistically significant (p<0.01).

• 대한치과교정학회지
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• 제40권5호
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• pp.314-324
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• 2010

본 연구는 성인 환자를 대상으로 안면골의 수평적, 수직적 골격 형태에 따른 하악 전치부 치조골의 순설측 두께를 하악 전치 치축을 기준으로 계측하고, 하악 이부 치조골의 단면적을 비교해 형태학적 차이를 확인해 보기 위하여 시행되었다. 20세 이상 성인 환자들의 초진 시 측모두부 방사선 사진을 사용하여, 수평적, 수직적 분류 기준에 따라 9군으로 분류하여 무작위로 30명(남자 15명, 여자 15명)씩, 총 270명을 추출하였다. 수평적 골격 형태를 판단하는 기준으로 ANB 각도가 사용되었으며, 수직적 골격 형태를 판단하는 기준으로는 하악평면각(SN-MP 각도)을 사용하였다. 측모두부 방사선 사진에서 하악 전치부 치조골의 협설측 두께와 하악 이부 치조골의 단면적을 계측하여 형태학적 차이를 확인해 보았다. 연구 결과로 high angle group은 low angle group과 average group에 비해 CEJ 하방 2 mm 부위 아래의 협설측 치조골과 모든 부위의 설측 치조골에서 통계적으로 유의하게 얇은 두께를 보였으며 ($p$ < 0.05), low angle group과 average group 중에서 Class I, II group은 모든 부위에서 Class I average group에 비해 유사하거나 통계적으로 유의하게 두꺼운 치조골 두께를 보였다 ($p$ < 0.05). Average group 내에서 Class III group은 Class I, II group에 비해 치근 중간 부위의 협설측과 설측에서 통계적으로 유의하게 얇은 치조골 두께를 보였으며 ($p$ < 0.05), high angle group 중에서도 특히 Class III인 high angle group에서 더 얇은 평균 치조골 두께를 보였다. 수직적 안면 골격 형태에 따라 하악 이부 치조골의 단면적은 통계적으로 유의한 차이를 보이지 않았다 ($p$ > 0.05). 이상의 결과에서 성인의 교정 치료 시 Class III이면서도 high angle을 보이는 환자에서는 하악 전치부에서 얇은 치조골 두께를 가지게 되는 경우가 많으므로, 하악 전치의 위치를 결정할 때 주의를 기울여야 할 것으로 생각한다.