• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제45권6호
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• pp.332-342
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• 2019

Objectives: Socket grafting is vital to prevent bone resorption after tooth extraction. Several techniques to prevent resorption have been described, and various bone graft substitutes have been developed and used with varying success. We conducted this pilot study to evaluate the performance of nanohydroxyapatite (nHA) derived from chicken eggshells in socket preservation. Materials and Methods: This was a prospective, single center, outcome assessor-blinded evaluation of 23 sockets (11 patients) grafted with nHA and covered with platelet-rich fibrin (PRF) membrane as a barrier. Bone width and radiographic bone density were measured using digital radiographs at 1, 12, and 24 weeks post-procedure. Postoperative histomorphometric and micro-computed tomography (CT) evaluation were performed. The study protocol was approved by the Institutional Ethics Committee. Results: All patients had uneventful wound healing without graft material displacement or leaching despite partial exposure of the grafted socket. Tissue re-epithelialized with thick gingival biotype (>3 mm). Width of the bone was maintained and radiographic density increased significantly with a trabecular pattern (73.91% of sockets) within 12 weeks. Histomorphometric analysis showed 56.52% Grade 3 bone formation and micro-CT analysis revealed newly formed bone with interconnecting trabeculae. Conclusion: Use of a PRF membrane with nHA resulted in good bone regeneration in sockets. Use of a PRF membrane prevents periosteal-releasing incisions for primary closure, thereby facilitating the preservation of keratinized mucosa and gingival architecture. This technique, which uses eggshell-derived nHA and PRF membrane from the patient's own blood, is innovative and is free of disease transfer risks. nHA is a promising economic bone graft substitute for bone regeneration and reconstruction because of the abundant availability of eggshell waste as a raw material.

• Journal of Audiology & Otology
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• 제24권1호
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• pp.17-23
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• 2020

Background and Objectives: We aimed to measure the head dimensions on computed tomography (CT) images, to compare them to directly measured head dimensions, and to predict a new parameter of bone thickness for aiding bone conduction implant (BCI) placement. Subjects and Methods: We reviewed the facial and mandibular bone CT images of 406 patients. Their head sizes were analyzed using five parameters included in the 6th Size Korea project, and they were divided into age groups (ranging from the 10s to the 80s). We compared the head length, head width, sagittal arc, bitragion arc, and head circumference in the CT and Size Korea groups. We also added the parameter bone thickness for aiding BCI placement. Results: All the head size parameters measured using CT were significantly smaller than those measured directly, with head length showing the smallest difference at 7.85 mm. The differences in the other four parameters between the two groups according to patient age were not statistically significantly different. Bone thickness had the highest value of 4.89±0.93 mm in the 70s and the lowest value of 4.10±0.99 mm in the 10s. Bone thickness also significantly correlated with head width (p=0.038). Conclusions: Our findings suggested that the CT and direct measurements yielded consistent data. Moreover, CT enabled the measurement of bone sizes, including bone thickness, that are impossible to measure directly. CT measurements may complement direct measurements in the Size Korea data when used for developing bone conduction hearing devices (BCIs and headsets) for the Korean population.

• 대한청각학회지
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• 제24권1호
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• pp.17-23
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• 2020

Background and Objectives: We aimed to measure the head dimensions on computed tomography (CT) images, to compare them to directly measured head dimensions, and to predict a new parameter of bone thickness for aiding bone conduction implant (BCI) placement. Subjects and Methods: We reviewed the facial and mandibular bone CT images of 406 patients. Their head sizes were analyzed using five parameters included in the 6th Size Korea project, and they were divided into age groups (ranging from the 10s to the 80s). We compared the head length, head width, sagittal arc, bitragion arc, and head circumference in the CT and Size Korea groups. We also added the parameter bone thickness for aiding BCI placement. Results: All the head size parameters measured using CT were significantly smaller than those measured directly, with head length showing the smallest difference at 7.85 mm. The differences in the other four parameters between the two groups according to patient age were not statistically significantly different. Bone thickness had the highest value of 4.89±0.93 mm in the 70s and the lowest value of 4.10±0.99 mm in the 10s. Bone thickness also significantly correlated with head width (p=0.038). Conclusions: Our findings suggested that the CT and direct measurements yielded consistent data. Moreover, CT enabled the measurement of bone sizes, including bone thickness, that are impossible to measure directly. CT measurements may complement direct measurements in the Size Korea data when used for developing bone conduction hearing devices (BCIs and headsets) for the Korean population.

• Journal of Periodontal and Implant Science
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• 제51권2호
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• pp.88-99
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• 2021

Purpose: Direct intraoral scanning and superimposing methods have recently been applied to measure the dimensions of periodontal tissues. The aim of this study was to analyze various correlations between labial gingival thickness and underlying alveolar bone thickness, as well as clinical parameters among 3 tooth types (central incisors, lateral incisors, and canines) using a digital method. Methods: In 20 periodontally healthy subjects, cone-beam computed tomography images and intraoral scanned files were obtained. Measurements of labial alveolar bone and gingival thickness at the central incisors, lateral incisors, and canines were performed at points 0-5 mm from the alveolar crest on the superimposed images. Clinical parameters including the crown width/crown length ratio, keratinized gingival width, gingival scallop, and transparency of the periodontal probe through the gingival sulcus were examined. Results: Gingival thickness at the alveolar crest level was positively correlated with the thickness of the alveolar bone plate (P<0.05). The central incisors revealed a strong correlation between labial alveolar bone thickness at 1 and 2 mm, respectively, inferior to the alveolar crest and the thickness of the gingiva at the alveolar crest line (G0), whereas G0 and labial bone thickness at every level were positively correlated in the lateral incisors and canines. No significant correlations were found between clinical parameters and hard or soft tissue thickness. Conclusions: Gingival thickness at the alveolar crest level revealed a positive correlation with labial alveolar bone thickness, although this correlation at identical depth levels was not significant. Gingival thickness, at or under the alveolar crest level, was not associated with the clinical parameters of the gingival features, such as the crown form, gingival scallop, or keratinized gingival width.

• 대한치과의사협회지
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• 제55권1호
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• pp.30-41
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• 2017

Inadequate keratinized mucosa around dental implants can lead to more plaque accumulation, tissue inflammation, marginal recession and attachment loss. We evaluated the effects of free gingival and extracellular matrix membrane grafts performed to increase the insufficient width of keratinized tissue around dental implants in the posterior mandible. A 47-year-old female patient presented with discomfort due to swelling of the lower right second premolar area. Due to severe destruction of alveolar bone, the tooth was extracted. After 3 months, a guided bone regeneration (GBR) procedure was performed and then a dental implant was placed 6 months later. During the second-stage implant surgery, free gingival grafting was performed to increase the width of the keratinized tissue. After 12 months, a clinical evaluation was performed. A 64-year-old female patient had a missing tooth area of bilateral lower molar region with narrow zone of keratinized gingiva and horizontal alveolar bone loss. Simultaneous implant placement and GBR were performed. Five months after the first-stage implant surgery, a gingival augmentation procedure was performed with an extracellular matrix membrane graft to improve the width of the keratinized tissue in the second-stage implant surgery. After 12 months, a clinical evaluation was performed. In these two clinical cases, 12 months of follow-up, revealed that the increased width of the keratinized tissue and the deepened oral vestibule was well maintained. A patient showed a good oral hygiene status. In conclusion, increased width of keratinized tissue around dental implants could improve oral hygiene and could have positive effects on the long-term stability and survival rate of dental implants. When planning a keratinized tissue augmentation procedure, clinicians should consider patient-reported outcomes.

• Journal of Periodontal and Implant Science
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• 제33권4호
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• pp.563-571
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• 2003

One of the central components of periodontal therapy is the improvement of esthetics. The presence and appearance of interdental papillae plays an important role of periodontal esthetics. The aim of the present study was to investigate how immediate provisional restoration preserve the shape of interdental papilla around the extraction socket and the width of bucco-lingual of gingiva. Another aim was to investigate the change in the interdental papilla and the amount of vertical bone fill of a extraction socket in relation to the interdental alveolar bone levels adjacent the alveolar socket. A total of 19 patients (11 male, 8 female, mean age of 50.57${\pm}$8.16), who visited the Department of Periodontology, Pusan National University and had more than one anterior tooth scheduled to be extracted due to an advanced periodontal disease were included in the present study. After initial periodontal therapy, the extracted teeth were reshaped of the root and placed into the socket followed by splinting with adjacent teeth with self-curing resin. The width of hucco-lingual of gingiva and interdental papilla height were measured at baseline, 1, 3, 6, 9 and 12 month and the periapical radiographic examination were taken at baseline, 6 and 12month following the extraction. The amount of vertical bone fill in the extraction socket were calculated. At 12 months following the extraction, the changes in mesial and distal interdental papilla and the width of bucco-lingual showed -1.06${\pm}$0.48mm, -0.844${\pm}$0.50mm, -1.50${\pm}$0.96m, relatively. The positional change in the interproximal papillae was significantly associated with the interdental bone level adjacent to the extraction socket(p=0.028). The higher the interproximal bone level adjacent the extraction socket, the greater the amount of bone fill in the extraction socket(p<0.001). In conclusion, it was thought that immediate provisional restoration could minimize the loss of the width of bucco-lingual and interproximal papillae around the extraction socket. In addition, the higher the interproximal bone level adjacent the extraction socket, the greater the amount of bone fill and the smaller the reduction of papillary height around the extraction socket.

• 대한치과교정학회지
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• 제37권3호
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• pp.212-219
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• 2007

현재 교정용 미니 임플란트의 식립부위에 대한 연구는 주로 구치부 치근사이 공간에 집중되어 왔으며, 연조직에 관한 연구는 부족하다. 본 연구의 목적은 하악골에서 전치부와 구치부의 치근사이 피질골과 연조직 두께를 측정하여 해부학적인 지도를 만들고, 한국인의 평균 부착치은의 폭경을 제시하는데 있다. 연구를 위하여 자원한 남자 15명, 여자 15명 총 30명을 대상으로 하였으며, 평균연령은 27세 3개월이었다. 구강 내 인상을 채득한 후 석고모형을 만들어 0.5 mm두께의 평판으로 스텐트를 제작하였다. 스텐트의 중절치에서 제1대구치까지 치근사이 치은변연을 연결한 선에 방사선 불투과성의 표식을 부착하고 구강 내에 장착한 후 3차원 CT 영상을 얻고, 각 치근사이 치조정 하방에서 2, 4, 6, 8 mm부위의 피질골 두께를 측정하였다. 연조직 두께는 스텐트의 각 치근사이 치조정 하방에서 2, 4, 6, 8 mm부위에 구멍을 뚫고 구강 내에서 근관치료용 파일을 연조직에 통과시켜 측정하였다. 석고모형 상에서 중절치에서 제1대구치까지 각 치근중앙 부위에서 부착치은의 폭경을 측정하였다. 연구결과 하악골에서 전체대상자의 평균 피질골 두께는 $1.33{\pm}0.38mm$이었으며 전치부에서 구치부로 갈수록 두꺼워지고, 평균 연조직 두께는 $1.49{\pm}0.54mm$이었으며 치근단 쪽으로 내려가면서 두께가 변하지 않았다. 평균 전체 두께는 $2.82{\pm}0.70mm$이었으며 전치부에서 구치부로 갈수록 두꺼워졌다. 부착치은의 폭경은 전치부가 구치부보다 넓었다. 이상의 결과는 피질골과 연조직 두께, 부착치은의 폭경을 고려하여 미니 임플란트의 식립부위를 결정하는 것이 필요함을 시사하였다.

• 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.

• 구강회복응용과학지
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• 제28권3호
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• pp.277-290
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• 2012

최근 치과 임플란트는 구강 내 무치악 부위의 보편적인 수복 방법으로 임상가 뿐만 아니라 환자들에게도 널리 인식되어 있다. 외상, 만성 치주염 등 다양한 원인에 의해 상악 전치부는 발치 후 급속한 순측 골흡수가 진행될 수 있다. 그로 인해 협소한 순구개 폭경을 가진 상악 전치부 치조제 상에 임프란트 식립 시 열개 및 천공형 골결손이 발생할 수 있다. 이 경우 골유도 재생술을 사용하여 상악 전치부 치조제를 증강시킬 수 있다. 골유도 재생술시 골이식재에 조직 접착제를 혼합하여 기계적 및 생물학적 이점을 얻을 수 있다. 본 증례에서는 순설 폭경이 얇은 상악 전치부 치조제 상에 임플란트 식립에 의한 열개 및 천공형 골결손 발생시 자가골을 제외한 동종골, 이종골, 그리고 합성골 입자형 골이식재 등을 다양하게 조합한 후 조직 접착제와 혼합하여 골유도 재생술을 진행하였다. 모든 증례에서 양호한 치조제 증강을 보였음에 보고하는 바이다.

• 대한치과보철학회지
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• 제48권4호
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• pp.266-272
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• 2010

연구 목적: 임플란트 경부 역사면의 디자인이 변연골 응력분포에 미치는 영향을 알아보기 위해 유한요소법을 사용하여 비교분석하였다. 연구 재료 및 방법:경부 직경 5.5 mm, 길이 8 mm의 매립형 (submerged type) 고정체 (Dentis Co., Daegu, Korea)를 연구모델로 선정하였다. 임플란트 경부 역사면의 디자인을 높이 (h, 0.4 mm, 1.0 mm)와폭경({5.5 - (3.34 + 2b)} / 2, [b, 0.2 mm, 0.3 mm, 0.4 mm])을 다르게 하여 총 여섯 가지의 실험 임플란트 조합으로 구분하였다. 축대칭 유한요소모델링을 이용하여 임플란트/악골 복합체에 대해 임플란트 장축에 평행한 방향으로 치관 교합면의 중심부에 수직 하중 100 N이 작용할 때 변연골의 최대압축응력을 산출하여 비교 하였다. 결과: 여섯 개의 모든 실험 임플란트 모델에서 변연골의 응력집중이 관찰되지 않았다. 변연골 응력은 임플란트 경부 역사면의 폭과 높이의 차이에 따라 달라지는 것이 관찰되었으며 사면각이 클수록 응력 집중이 증가하는 경향을 보였다. 결론: 임플란트 경부 역사면 디자인의 부여는 변연골 응력 분포 개선에 중요한 역할을 할 수 있을 것으로 여겨진다.