• Maxillofacial Plastic and Reconstructive Surgery
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• 제30권3호
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• pp.266-275
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• 2008

저자들은 잔존 치조골의 흡수 및 위축으로 통상적인 임플란트 시술이 어려운 증례에서 하악골의 하악지에서 자가골을 채취하여 이를 증례에 따라 블록형 혹은 입자형으로 골 이식술을 시행하여 다양한 증례에 적용하여 비교적 만족할 만한 임플란트 식립 수술이 가능하였던 바 이를 문헌고찰과 함께 보고하며, 본 연구에서는 다양한 술식의 임상적 활용에 대해서만 보고하였으나 향후 이러한 증례들에 대하여 보다 장기적인 추적조사와 골 이식된 부위의 골 조직의 재형성 식립된 임프란트의 보철적인 기능과 장기적인 예후에 대한보다 체계적인 연구가 필요하리라 사료된다.

• 대한치과보철학회지
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• 제35권4호
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• pp.674-696
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• 1997

There're many cases that should be reconstructed with post and core when clinical crown is destructed. But this post and core restoration may cause damaging stress on the teeth. Previous finite element study was restricted to normal bone model relatively close to cemen-toenamel junction. Moreover, the test of a model with diminished bone support was rare. The purpose of this study is to test the effects of alveolar bone loss on the magnitude, stress distribution and displacement of post reconstructed teeth. In this study, it was assumed that the coronal portion of upper incisor was severely destructed. After conventional endodontic treatment, it was restored with post and core. The PFM restoration was made on it. This crown was cemented with ZPC. Alveolar bone was classified by 4 types of bone, such as normal, 2 mm, 4 mm, 6 mm bone, according to the bone loss. Meanwhile, the material of post are divided into 2 types of materials, such as gold, co-cr. Force was applied to two directions. One was fuctional maximum bite force (300 N) applied to the spot just lingual to the incisal edge with the angle of 45 degree to the long axis of the tooth, and the other one was horizontal force (300 N) applied to the labial surface. The results analyzed with three dimensional finite element method were as follows : 1. Stress was concentrated on the adjacent dentin of the post apex, one third portion of the post apex and the labial & lingual mid-portion of the root in all case. The stress of middle third of the root was apparently concentrated on the labial aspect. 2. The stress on adjacent dentin of the post apex and one third of the post apex increased as alveolar bone height moved apically. This increase was dramatic beyond 4 mm bone loss model. 3. The stress of the post apex was spreaded to the middle third of the post and greater than gold post in the case of metal post. 4. The displacement of the neck of post was the greatest in one of the post-cement interface and this increased as alveolar bone height moved apically. Besides the displacement of the metal post is slightly lower than one of the gold post.

• Journal of Periodontal and Implant Science
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• 제31권1호
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• pp.57-74
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• 2001

The purpose of this study was to evaluate the adjunctive combined effect of demineralized freeze-dried bone allograft(DFDB) in guided bone regeneration on supra-alveo-lar peri-implant defect. Supra-alveolar perio-implant defects, 3mm in height, each including 4 IMZ titanium plasma-sprayed implants were surgically created in two mongrel dogs. Subsequently, the defects were treated with 1 of the following 3 modalities: Control) no membrane or graft application, Group1) DFDB application, Group2) guided bone regeneration using an expanded polytetra-fluoroethylene membrane, Group3) guided bone regeneration using membrane and DFDB. After a healing period of 12-week, the animals were sacrificed, tissue blocks were harvested and prepared for histological analysis. Histologic examination were as follows; 1. New bon formation was minimal in control and Group 1, but considerable new bone formation was observed in Group 2 and Group 3. 2. There was no osteointegration at the implant-bone interface in the high-polished area of group2 and Group 3. 3. In fluorescent microscopic examination, remodeling of new bone was most active during week 4 and week 8. There was no significant difference in remodeling rate between group 2 and group 3. 4. DFDB particles were observed, invested in a connective tissue matrix. Osteoblast activity in the area was minimal. The results suggest that guided bone regeneration shows promising results in supra-alveolar peri-implant defects during the 12 week healing period although it has a limited potential in promoting alveolar bone regeneration in the high-polished area. There seems to be no significant adjunctive effect when DFDB is combined with GBR.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제27권3호
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• pp.238-247
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• 2005

The placement of different graft materials and/or the use of occlusive membranes to cover the extraction socket entrance are techniques aimed at reducing alveolar ridge resorption and enhancing bone formation. However, in spite of its clinical advantage, the use of graft materials in fresh extraction socket has been questioned because particles of the grafted material have been found in alveolar sockets with fibrous union. The purposes of this study were to evaluate whether alveolar ridge resorption following tooth extraction could be reduced and bone formation could be enhanced by the application of absorbable gelatin spongy or gelatin spongy soaked with platelet rich plasma(PRP) used as a space filler in clinical and radiographic aspects. Eighty patients who were scheduled for extraction of both third molars were participated and carried out by one experienced surgeon. Following extraction of teeth, one extracted socket were treated with gelatin spongy as an experimental group A and the other were treated with gelatin spongy and PRP as an experimental group B. The routine extracted socket were healed without any treatment as a control group. From the period of extraction to 12 weeks postoperatively, we examined the clinical course and radiographic evaluation on socket at regular interval. Both experimental groups showed faster wound healing process than control clinically. Vertical gingival height of the extraction socket were less changed statistically in both experimental groups than control. The horizontal width change of the extraction socket were not significant statistically in any group. Radiographic changes of the alveolar bone height were less changed in both experimental groups and bone density were showed higher than control. There were a little difference between experimental group A and B. In conclusion, absorbable gelatin sponge and with PRP were considered as having preservation effects of extraction socket and stimulation of bone formation process after extraction.

• 대한치과교정학회지
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• 제47권5호
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• pp.313-322
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• 2017

Objective: Miniscrew-assisted rapid palatal expansion (MARPE) is a means for expanding the basal bone without surgical intervention in young adults. Here, we assessed the differences in dental, alveolar, and skeletal measurements taken before (T0), immediately after (T1), and 1 year after (T2) MARPE. Methods: Twenty-four patients (mean age, 21.6 years) who had undergone MARPE and cone-beam computed tomography at T0, T1, and T2 were included. Changes in the following parameters were compared using paired t-tests: intercusp, interapex, alveolar, nasal floor, and nasal cavity widths; inclination of the first molar (M1) and its alveolus; and thickness and height of the alveolar bone. A linear mixed-effects model was used to determine variables that affected periodontal changes in the M1. Results: MARPE produced significant increases in most measurements during T0-T2, despite relapse of some measurements during T1-T2. The alveolar thickness decreased on the buccal side, but increased on the palatal side. The alveolar crest level at the first premolar moved apically. Changes in the thickness and height of the alveolar bone were affected by the corresponding initial values. Conclusions: MARPE can be used as an effective tool for correcting maxillomandibular transverse discrepancy, showing stable outcomes 1 year after expansion.

• 대한치과교정학회지
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• 제31권2호통권85호
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• pp.209-223
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• 2001

치조골 결손을 갖는 환자의 상악전치부 압하(intrusion)시 필수적인 pure intrusion을 위해 three-piece base arch appliance와 후방견인력의 적용이 필요하게 된다. Three-piece base arch appliance를 적용한 상악전치부 압하시의 상악 6전치, 치근막 및 치조골의 3차원 유한요소모델을 제작하였다. Three-piece base arch appliance를 이용한 상악 전치부압하시 치아 수에 따른 저항중심의 위치, 치조골 흡수에 따른 pure intrusion을 위한 후방견인력 변화 양상, 그리고 이때의 치조골 높이에 따른 저항중심의 수직적, 수평적 위치 변화의 상관관계에 대해 다음과 같은 결과를 얻었다. 1. 치축 경사도와 치조골 높이가 정상이고, 압하시 three-piece base arch appliance를 이용한 경우 압하 하중점이 전후방적으로 저항중심을 통과하기 위한 조건은 다음과 같다. 1) 2 전치군(중절치군)을 대상으로 한 경우에는 중절치 브라켓 원심면에서 후방 6mm 지점으로, 측절치 브라켓 전방 1/3부위에 위치 하였다. 2) 4 전치군(중절치와 측절치군)을 대상으로 한 경우에는 측절치 브라켓 원심면에서 후방 5mm지점으로, 측절치와 견치 브라켓 사이 공간의 후방 2/3부위에 위치하였다. 3) 6 전치군(중절치, 측절치와 견치군)을 대상으로 한 경우에는 견치 브라켓 원심면에서 후방 7mm 지점으로, 제 1소구치 브라켓 중앙부위에 위치하였다. 4) 치아 수 증가에 따른 저항중심의 후방이동을 관찰할 수 있었고, 4 전치군 보다 6 전치군에서 후방 이동량이 크게 나타났다. 2. 치조골 높이가 정상일 때, pure intrusion을 위한 후방견인력을 적용할 경우 수직 압하점은 저항중심과 같거나 약간 전방에 위치했다. 3. 동일한 압하력과 압하점 적용시 치조골 상실 증가에 따른 압하시 pure intrusion을 위한 후방견인력 변화는 다음과 같다. 1) 2 전치군과 4 전치군의 후방 견인력은 6 전치군의 후방 견인력에 비해 낮게 나타났다. 2) 치조골이 상실됨에 따라 각 치아군 후방견인력은 증가됨을 보였다. 4. 상악 전치부 치아군과 치조골 높이에 따른 저항중심의 수평적, 수직적 위치간 상관관계는 다음과 같다. 1) 2 전치군일 때, 치조골 상실에 따른 저항중심의 수직적 위치변화에 대한 수평적 위치 변화가 가장 크게 나타났다. 치아 수가 증가할수록 치조골 상실에 따른 저항중심의 수직적 위치 변화에 대한 수평적 위치변화는 작아지는 경향을 보였다. 2) 치조골 상실량이 커짐에 따라서는, 치아 수에 관계 저항중심의 수직적 위치변화에 대해 수평적 위치변화가 커졌다.

• Journal of Periodontal and Implant Science
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• 제50권1호
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• pp.38-47
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• 2020

Purpose: The aim of this study was to investigate the available alveolar bone height between the maxillary molars and the sinus floor according to their anatomical relationship using cone-beam computed tomographic (CBCT) images. Methods: A total of 752 maxillary first (M1) and second molars (M2) on CBCT scans of 188 patients were selected. First, each maxillary molar was categorized as type 1, 2, 3, or 4 according to the relationship of the molar root with the maxillary sinus floor. The frequency distribution of each type was analyzed. Second, the shortest vertical distance (VD) of each molar was measured from the furcation midpoints of the roots to the lowest point of the sinus floor by 2 observers. Intraclass correlation coefficients and the t-test were calculated for the VD measurements. Results: For M1, type 3 was the most frequent, followed by type 2. For M2, type 3 was the most common, followed by type 1. The VD measurements of type 1 were 9.51±3.68 mm and 8.07±2.73 mm for M1 and M2, and those of type 3 were 3.70±1.52 mm and 4.03±1.53 mm for M1 and M2, respectively. The VD measurements of M2 were significantly higher in female patients than in male patients. Conclusions: Type 3 was the most frequent anatomical relationship in the maxillary molars, and showed the lowest alveolar bone height. This information will help clinicians to prevent complications related to the maxillary sinus during maxillary molar treatment and to predict the available bone height for immediate implant planning.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제33권4호
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• pp.314-318
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• 2011

Purpose: The purpose of this study is to evaluate the results of alveolar bone grafting in patients with various types of cleft lip and to compare the success rates according to the lateral incisors and canines. Methods: The postoperative radiographs of 20 patient with a cleft lip and alveolar process alone (CLAP), complete unilateral cleft lip and palate (UCLP) and complete bilateral cleft lip and palate (BCLP) were retrospectively analyzed. The alveolar bone height was classified according to ${\AA}$byholm (1981) and Bergland (1986) and we evaluated the dentition at the time of surgery and the existence of a lateral incisor and impacted canines. Results: 16 (80%) of the 20 patients were assigned to Type I & II and they were considered successful. In the UCLP group, the success rate was significantly better than that of the UCLP and BCLP groups. The success rate was significantly better than when the cleft was grafted with the existence of a lateral incisor and before the eruption of the canines. Conclusion: The severity of the deformity influenced the success rate. The timing of the operation was a critical variable that affected the outcome in patients with cleft lip and palate.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제43권2호
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• pp.100-105
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• 2017

Objectives: Localization of the mandibular canal (MC) and measurement of the height and width of the available alveolar bone at the proposed implant site in the posterior segment of the mandible using cone-beam computed tomography (CBCT) in patients with a single missing tooth. Materials and Methods: A cross-sectional study was performed where CBCT scans of the patients with a single missing tooth in the posterior segment of the mandible-premolar, I (1st) molar, and II (2nd) molar were used. The scans were assessed using OnDemand3D software (version 1.0; CyberMed Inc., Seoul, Korea) for localization of the MC asnd remaining alveolar bone both vertically (from the superior position of the MC to the crest of the alveolar ridge) and horizontally (buccolingual, 3 mm below the crest of the alveolar ridge). The findings were statistically analyzed using independent t-test. Results: A total of 120 mandibular sites (40 sites for each of the three missing premolar, I molar, and II molar) from 91 CBCT scans were analyzed. The average heights (from the alveolar crest to the superior margin of the MC) at the premolar, I molar, and II molar areas were $15.19{\pm}2.12mm$, $14.53{\pm}2.34mm$, and $14.21{\pm}2.23mm$, respectively. The average widths, measured 3 mm below the crest of the alveolar ridge, at the premolar, I molar, and II molar areas were $6.22{\pm}1.96mm$, $6.51{\pm}1.75mm$, and $7.60{\pm}2.08mm$, respectively. There was no statistically significant difference between males and females regarding the vertical and horizontal measurements of the alveolar ridges. Conclusion: In the study, the measurements were averaged separately for each of the single missing teeth (premolar, I molar, or II molar), giving more accurate information for dental implant placement.

• The Journal of Advanced Prosthodontics
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• 제6권1호
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• pp.53-59
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• 2014

PURPOSE. The aim of this study was to obtain statistical data on the residual bone height at different natural tooth positions by panoramic radiography in edentulous Korean patients aged 60-90 years. MATERIALS AND METHODS. The study included the diagnostic panoramic radiographs of 180 randomly selected edentulous patients without systemic diseases affecting bone. The radiographic selection criteria included absence of obvious facial asymmetry, clearly visible anatomic structures, and no surgical and fracture history. The panoramic radiographs of 79 patients met these criteria and were used in the analysis. The same researcher processed all the radiographs by using a standardized method. The height of the residual bone was measured at 18 predetermined sites (7 in the maxilla and 11 in the mandible) on digitized and printed radiographs by using a Digimatic caliper, triangle, and ruler. Gender- and age-related differences were statistically analyzed by using the t-test and rank-sum test (${\alpha}=0.05$). RESULTS. The maxillary residual bone height did not show significant gender-related differences, but male patients had significantly higher residual bone in the mandible(P<.05). No significant height differences at the measured sites were noted among the 60s, 70s, and 80s age groups. CONCLUSION. Dentists should pay greater attention to older female edentulous patients because they are more prone to rapid residual bone resorption. Residual bone resorption may not be affected by age.