Growth and Age-Related Abnormalities in Cortical Structure and Fracture Risk

시먼에고 대한내분비학회 2015 Endocrinology and metabolism Vol.30 No.4

Vertebral fractures and trabecular bone loss have dominated thinking and research into the pathogenesis and the structural basis of bone fragility during the last 70 years. However, 80% of all fractures are non-vertebral and occur at regions assembled using large amounts of cortical bone; only 20% of fractures are vertebral. Moreover, ~80% of the skeleton is cortical and ~70% of all bone loss is cortical even though trabecular bone is lost more rapidly than cortical bone. Bone is lost because remodelling becomes unbalanced after midlife. Most cortical bone loss occurs by intracortical, not endocortical remodelling. Each remodelling event removes more bone than deposited enlarging existing canals which eventually coalesce eroding and thinning the cortex from ‘within.’ Thus, there is a need to study the decay of cortical as well as trabecular bone, and to develop drugs that restore the strength of both types of bone. It is now possible to accurately quantify cortical porosity and trabecular decay in vivo. The challenges still to be met are to determine whether measurement of porosity identifies persons at risk for fracture, whether this approach is compliments information obtained using bone densitometry, and whether changes in cortical porosity and other microstructural traits have the sensitivity to serve as surrogates of treatment success or failure.

Distribution of Cortical Bone in Bovine Limbs

CHOI, Sung-Jin,LEE, Jong-Il,KIM, Nam-Soo,CHOI, In-Hyuk Japanese Society of Veterinary Science 2006 The Journal of veterinary medical science Vol.68 No.9

<P>Xenogenic bone grafts have been widely researched because they are not limited in terms of volume and size like autogenous and allogenic grafts, and the favored bone for xenografts is bovine bone. However, the efficacy of cortical bone from bovine limb for xenografts is not clearly known. In this study, the distribution of cortical bone in bovine humerus, radius, femur, and tibia were investigated. Each experimental bone was split longitudinally with a bone saw and bone marrow and cancellous bone were removed. The thicknesses of cortical layers in sample diaphyses were measured at 1cm intervals using a micrometer. The mean lengths of cortical portions were; humerus 14.7 ± 2.3 cm, radius 19.0 ± 2.6 cm, femur 19.0 ± 3.2 cm, and tibia 23.0 ± 3.1 cm. Thickest cortical bone was found at the distal caudal metaphysis of the humerus, the proximal caudal metaphysis of the radius, the craniolateral and caudomedial midshaft of the femur and the lateral and medial midshaft of tibia. The mean surface areas of cortical bone were humerus 187.4 ± 15.44 cm<SUP>2</SUP>, radius 229.2 ± 43.31 cm<SUP>2</SUP>, femur 295.8 ± 8.93 cm<SUP>2</SUP>, and tibia 290.0 ± 30.44 cm<SUP>2</SUP>. And, mean volumes of cortical bone were humerus 149.42 ± 15.35 cm<SUP>3</SUP>, radius 166.26 ± 20.02 cm<SUP>3</SUP>, in femur 220.45 ± 22.73 cm<SUP>3</SUP>, and tibia 214.89 ± 20.05 cm<SUP>3</SUP>. The results of this study can be used to produce cortical bone-based plates and screws.</P>

Evaluation of mandibular cortical bone thickness for placement of temporary anchorage devices (TADs)

김정훈,박영철 대한치과교정학회 2012 대한치과교정학회지 Vol.42 No.3

Objective: In this study, we measured the cortical bone thickness in the mandibular buccal and lingual areas using computed tomography in order to evaluate the suitability of these areas for application of temporary anchorage devices (TADs) and to suggest a clinical guide for TADs. Methods: The buccal and lingual cortical bone thickness was measured in 15 men and 15 women. Bone thickness was measured 4 mm apical to the interdental cementoenamel junction between the mandibular canine and the 2nd molar using the transaxial slices in computed tomography images. Results: Th e cortical bone in the mandibular buccal and lingual areas was thicker in men than in women. In men, the mandibular lingual cortical bone was thicker than the buccal cortical bone, except between the 1st and 2nd molars on both sides. In women, the mandibular lingual cortical bone was thicker in all regions when compared to the buccal cortical bone. Th e mandibular buccal cortical bone thickness increased from the canine to the molars. Th e mandibular lingual cortical bone was thickest between the 1st and 2nd premolars, followed by the areas between the canine and 1st premolar, between the 2nd premolar and 1st molar, and between the 1st molar and 2nd molar. Conclusions: Th ere is suffi cient cortical bone for TAD applications in the mandibular buccal and lingual areas. Th is provides the basis and guidelines for the clinical use of TADs in the mandibular buccal and lingual areas.

Evaluation of mandibular cortical bone thickness for placement of temporary anchorage devices (TADs)

Jung-Hoon Kim,Young-Chel Park 대한치과교정학회 2012 대한치과교정학회지 Vol.42 No.3

Objective: In this study, we measured the cortical bone thickness in the mandibular buccal and lingual areas using computed tomography in order to evaluate the suitability of these areas for application of temporary anchorage devices (TADs) and to suggest a clinical guide for TADs. Methods: The buccal and lingual cortical bone thickness was measured in 15 men and 15 women. Bone thickness was measured 4 mm apical to the interdental cementoenamel junction between the mandibular canine and the 2nd molar using the transaxial slices in computed tomography images. Results: The cortical bone in the mandibular buccal and lingual areas was thicker in men than in women. In men, the mandibular lingual cortical bone was thicker than the buccal cortical bone, except between the 1st and 2nd molars on both sides. In women, the mandibular lingual cortical bone was thicker in all regions when compared to the buccal cortical bone. The mandibular buccal cortical bone thickness increased from the canine to the molars. The mandibular lingual cortical bone was thickest between the 1st and 2nd premolars, followed by the areas between the canine and 1st premolar, between the 2nd premolar and 1st molar, and between the 1st molar and 2nd molar. Conclusions: There is sufficient cortical bone for TAD applications in the mandibular buccal and lingual areas. This provides the basis and guidelines for the clinical use of TADs in the mandibular buccal and lingual areas.

Evaluation of mandibular cortical bone thickness for placement of temporary anchorage devices (TADs)

Kim, Jung-Hoon,Park, Young-Chel The Korean Association Of Orthodontists 2012 대한치과교정학회지 Vol.42 No.3

Objective: In this study, we measured the cortical bone thickness in the mandibular buccal and lingual areas using computed tomography in order to evaluate the suitability of these areas for application of temporary anchorage devices (TADs) and to suggest a clinical guide for TADs. Methods: The buccal and lingual cortical bone thickness was measured in 15 men and 15 women. Bone thickness was measured 4 mm apical to the interdental cementoenamel junction between the mandibular canine and the 2nd molar using the transaxial slices in computed tomography images. Results: The cortical bone in the mandibular buccal and lingual areas was thicker in men than in women. In men, the mandibular lingual cortical bone was thicker than the buccal cortical bone, except between the 1st and 2nd molars on both sides. In women, the mandibular lingual cortical bone was thicker in all regions when compared to the buccal cortical bone. The mandibular buccal cortical bone thickness increased from the canine to the molars. The mandibular lingual cortical bone was thickest between the 1st and 2nd premolars, followed by the areas between the canine and 1st premolar, between the 2nd premolar and 1st molar, and between the 1st molar and 2nd molar. Conclusions: There is sufficient cortical bone for TAD applications in the mandibular buccal and lingual areas. This provides the basis and guidelines for the clinical use of TADs in the mandibular buccal and lingual areas.

Evaluation of mandibular cortical bone ratio on computed tomography images in patients taking bisphosphonates

Koo, Chul-Hong,Lee, Jae-Hoon Korean Association of Maxillofacial Plastic and Re 2018 Maxillofacial Plastic Reconstructive Surgery Vol.40 No.-

Background: Bisphosphonate (BP) has the ability to thicken the cortical bone. In addition, it has been reported that the cortical bone thickened by BP has relation to the medication-related osteonecrosis of the jaw (MRONJ). Therefore, the objective of this article is to analyze the ratio as well as thickness of cortical bone in the mandible using computed tomography (CT) and to evaluate it as the predictive factor of MRONJ. Methods: The thickness of the cortical bone was measured on a paraxial view of the CT showing the mental foramen in 95 patients: 33 patients with MRONJ (3 males, 30 females), 30 patients taking BP without MRONJ (2 males, 28 females), and 32 controls (9 males, 28 females). Also, the ratios of the cortical bone to the total bone were obtained using the measured values. Based on these results, we compared the difference of mandibular cortical bone ratio between the three groups. Results: The average cortical bone thickness was measured as 3.81 mm in patients with MRONJ, 3.39 mm in patients taking BP without MRONJ, and 3.23 mm in controls. There was only a significant difference between patients with MRONJ and controls (P < 0.05). On the other hand, the average mandibular cortical bone ratio was measured as 37.9% in patients with MRONJ, 27.9% in patients taking BP without MRONJ, and 23.3% in controls. There was a significant difference between all groups (P < 0.05). Conclusion: The mandibular cortical bone ratio is large in order of patients with MRONJ, patients taking BP without MRONJ, and controls. This result suggests that the mandibular cortical bone ratio would be very useful to predict the development of MRONJ.

Consideration of Lateral Cortical Bone Thickness and IAN Canal Location During Mandibular Ramus Bone Grafting for Implant Placement

Lee, Nam-Hoon,Ohe, Joo-Young,Lee, Baek-Soo,Kwon, Yong-Dae,Choi, Byung-Joon,Bang, Sung-Moon Korean Academy of Dental Science 2010 Journal of korean dental science Vol.3 No.2

Purpose: This study aimed at examining the thickness of lateral cortical bone in the mandibular posterior body and the location of the inferior alveolar nerve canal as well as investigating the clinically viable bone grafting site(s) and proper thickness of the bone grafts. Subjects and Methods: The study enrolled a total of 49 patients who visited the Department of Oral and Maxillofacial Surgery at Kyung Hee University Dental Hospital to have their lower third molar extracted and received cone beam computed tomography (CBCT) examinations. Their CBCT data were used for the study. The thickness of lateral cortical bone and the location of inferior alveolar nerve canal were each measured from the buccal midpoint of the patients' lower first molar to the mandibular ramus area in the occlusal plane of the molar area. Results: Except in the external oblique ridge and alveolar ridge, all measured areas exhibited the greatest cortical bone thickness near the lower second molar area and the smallest cortical bone thickness in the retromolar area. The inferior alveolar nerve canal was found to be located in the innermost site near the lower second molar area compared to other areas. In addition, the greatest thickness of the trabecular bone was found between the inferior alveolar nerve canal and the lateral cortical bone. Conclusions: In actual clinical settings involving bone harvesting in the posterior mandibular body, clinicians are advised to avoid locating the osteotomy line in the retromolar area to help protect the inferior alveolar nerve canal from damage. Harvesting the bone near the lower second molar area is judged to be the proper way of securing cortical bone with the greatest thickness.

Exploring and calibrating local curvature effect of cortical bone for quantitative ultrasound (QUS)

Chen, Jiangang,Su, Zhongqing,Cheng, Li,Ta, De-An Techno-Press 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.48 No.4

Apart from thinning of cortical layers, the local bone curvature, varying along bone periphery, modulates ultrasound waves as well, which is however often underestimated or overlooked in clinical quantitative ultrasound (QUS). A dedicated three-dimensional finite element modelling technique for cortical bones was established, for quantitatively exploring and calibrating the effect of local curvature of cortical bone on ultrasound. Using a correlation-based mode extraction technique, high-velocity group (HVG) and low-velocity group (LVG) wave modes in a human radius were examined. Experimental verification using acrylic cylinders and in vitro testing using a porcine femur were accomplished. Results coherently unravelled the cortical curvature exerts evident influence on bone-guided ultrasound when RoC/${\lambda}$ <1 for HVG mode and RoC/${\lambda}$ <2 for LVG mode (RoC/${\lambda}$: the ratio of local bone curvature radius to wavelength); the sensitivity of LVG mode to bone curvature is higher than HVG mode. It has also been demonstrated the local group velocity of an HVG or LVG mode at a particular skeletal site is equivalent to the velocity when propagating in a uniform cylinder having an outer radius identical to the radius of curvature at that site. This study provides a rule of thumb to compensate for the effect of bone curvature in QUS.

위턱뼈에서 미니임프란트 식립을 위한 물렁조직과 겉질뼈의 두께

박종태(Jong-Tae Park),정려령(Rye-Ryeng Jeong),김규탁(Kyu-Tag Kim),김상봉(Sang-Bong Kim),허경석(Kyung-Seok Hu),김희진(Hee-Jin Kim),임성훈(Sung-Hun Lim),김흥중(Heung-Joong Kim) 대한체질인류학회 2008 해부·생물인류학 (Anat Biol Anthropol) Vol.21 No.3

위턱뼈의 정중입천장봉합 부위와 어금니 사이는 교정용 미니임플란트를 식립하기에 적절한 장소이다. 이 연구는 물렁조직과 겉질뼈의 두께와 관련하여 미니임플란트를 가장 적절한 부위에 위치시키기 위한 장소에 대한 자료를 제공하고자 수행되었다. 연구용 사체 15구의 위턱뼈를, 정중입천장봉합 부위와 위턱 어금니 사이의 물렁조직과 겉질뼈의 두께를 계측하기 위해, 정중시상면과 볼쪽-입천장쪽면으로 절단하였다. 각 절단원 절편들을 스캐너로 스캔한 다음, 물렁조직과 겉질뼈의 두께를 측정하였다. 정중시상절편에서는 안쪽앞니 잇몸유두로부터 5㎜ 간격으로 6개의 지점의 두께를 측정하였고, 볼쪽-입천장쪽 절편에서는 이틀능선으로부터 치아뿌리끝쪽으로 1㎜ 간격으로 5개의 지정의 두께를 측정하였다. 정중입천장봉합 부위에서 물렁조직의 두께는 안쪽앞니 사이 잇몸유두로부터 15㎜ 지점에서 1.46㎜를 보였고, 그 뒤쪽에서 비교적 일정하다가 잇몸유로부터 35㎜ 지점 이후부터 급격히 증가하였다. 겉질뼈의 두께는 안쪽앞니 잇몸유두로부터 20㎜ 지점에서 2.13㎜로 가장 두꺼웠고, 그 뒤쪽 부위에서 일정한 두께를 보이다가 잇몸유두로부터 30㎜ 지점 이후부터 감소하였다. 입천장쪽의 물렁조직의 두께는 세 군 모두에서 이틀능선에서 1㎜ 지점에서 가장 얇았으며, 치아뿌리끝쪽으로 갈수록 점차 증가하였다. 입천장쪽 겉질뼈의 두께는 세 군 모두에서 이틀능선에서 1㎜ 지점에서 가장 두꺼웠으며, 치아뿌리끝쪽으로 갈수록 감소하였으나 그 차이는 미약하였다. 볼쪽 물렁조직의 두께는 세 군 모두에서 이틀능선에서 1㎜ 부위에서 가장 두꺼웠으며, 치아뿌리끝쪽으로 갈수록 점차 감소하였다. 볼쪽 겉질뼈의 두께는 세 군 모두에서 이틀능선에서 1㎜ 지점에서 가장 앓았으며, 치아뿌리끝쪽으로 갈수록 약간 증가하였다. 입천장쪽과 볼쪽을 비교하였을 때, 물렁조직의 두께는 입천장쪽이 더 두꺼웠고, 겉질뼈의 두께는 볼쪽이 입천장쪽보다 두꺼웠다. 위의 결과들은 위턱뼈 정중입천장봉합 부위와 어금니 사이에 미니임폴란트 식립 시 안전한 부위를 결정하는데 도움이 되는 물렁조직과 겉질뼈의 두께에 대한 해부학적 자료를 제공할 수 있을 것으로 생각된다. The midpalatal suture area and maxillary interdental area are suitable site for the placement of orthodontic mini-implant. The purpose of this study was to provide a guideline to indicate the best location for mini-implant placement as it relates to the thickness of soft tissue and cortical bone. Fifteen maxilla from 15 cadavers were cut in midsagittal plane and buccopalatal plane to measure the thickness of soft tissue and cortical bone of midpalatal and maxillary posterior interdental areas. Sectioned samples were scanned and the thickness was measured. The thickness of soft tissue and cortical bone were measured at 6 points from the interdental papilla with 5-mm intervals in the mid-sagittal section. And, the thickness of soft tissue and cortical bone were also measured at 5 points from the alveolar crest with I-mm intervals in the buccopalatal section. The mean and standard deviation of the measurement were calculated. Soft tissue thickness at the midpalatal suture area was 1.46 ㎜ at 15 ㎜ from the interdental papilla and remained uniformly thick posterior to this point, and steeply increased at 35 ㎜ area posteriorly. Cortical bone thickness were greatest (2.13 ㎜) at 20 ㎜ from the interdental papilla and remained uniformly thick posterior to this point, and decreased at 30 ㎜ area posteriorly. Palatal soft tissues thickness in all groups was thinnest at the 1 ㎜ from the alveolar crest and gradually increased from alveolar crest to apical portion. Cortical bone thickness in all groups was thickest at the 1 ㎜ from the alveolar crest and slightly decreased from alveolar crest to apical portion. Buccal soft tissue thickness in all groups was thickest at the 1 ㎜ from the alveolar crest and gradually decreased from alveolar crest to apical portion. Cortical bone thickness in all groups was thinnest at the 1 ㎜ from the alveolar crest and slightly increased from alveolar crest to apical portion. Soft tissue thicknesses were greater on the palatal side than on the buccal side. Cortical bone thicknesses of the buccal side were thicker than the palatal side. These results provide anatomical data of soft tissue and cortical bone thickness to assist in the determination of safe location for the mini-implant placement in the midpalatal and maxillary interdental areas.

교정용 미니스크류 식립 시 스크류의 길이, 직경 및 피질골 두께에 따른 응력 분포에 관한 3차원 유한요소법적 연구

임종원,김왕식,김일규,손충렬,변효인 대한치과교정학회 2003 대한치과교정학회지 Vol.33 No.1

본 연구는 교정치료 시 고정원 보강을 위해 사용되는 교정용 미니스크류의 길이, 직경 및 피질골 두께에 따른 응력분포 양상을 알아보기 위하여 시행되었다. 미니스크류의 길이와 직경 변화에 따른 응력 분포 양상을 관찰하기 위하여 식립되는 피질골의 두께를 1.0mm로 고정하고 미니스크류의 길이를 6.0mm, 8.0mm, 10.0mm, 12.0mm로, 직경을 1.2mm, 1.6mm, 2.0mm인 3차원 유한요소 모델을 제작하였다. 또한, 피질골의 두께 변화에 따른 응력 분포 양상을 관찰하기 위하여 미니스크류의 길이를 0.8mm로 고정하고 직경은 1.2mm, 1.6mm, 2.0mm로, 피질골의 두께는 1.0mm, 1.5mm, 2.0mm, 2.5mm인 3차원 유한 요소 모델을 제작하였다. 각각의 유한요소 모델의 미니스크류 head 중심에 200gm의 수평력을 가하여 응력 분포 양상과 크기를 3차원 유한요소 해석 프로그램인 ANSYS응 이용하여 비교한 결과 다음과 같은 결론을 얻었다. 1. 미니스크류 내부에서 나타나는 최대 응력값을 비교한 결과, 미니스크류의 직경이 1.2mm에서 2.0mm로 증가할수록 응력이 감소하였으며 같은 직경에서는 길이 증가에 상관없이 일정한 값을 유지하였다. 2. 피질골 및 해면골에 작용되는 최대 응력값을 비교한 결과, 미니스크류의 직경이 1.2mm에서 2.0mm로 증가할수록 응력이 감소하였으며 같은 직경에서는 길이 증가에 상관없이 일정한 값을 유지하였다. 3. 피질골 및 해면골에 작용되는 응력 분포를 관찰한 결과, 대부분의 응력이 피질골에서 흡수 되었으며, 해면골에 전달되는 응력값은 미미하였다. 4. 피질골 두께에 따른 최대 응력값을 비교한 결과, 같은 미니스크류의 직경에서는 피질골의 두께 증가에 상관없이 일정한 값을 유지하였다. 이상의 결과는 교정용 미니스크류의 유지에 길이보다는 직경이 더 크게 관여하는 것으로 나타나 미니스크류의 식립시 이에 대한 고려가 필요함을 시사하였다. The purpose of the present study is to evaluate the stress distribution on the length and diameter of the miniscrew and cortical bone width. Three dimensional finite element models were made of diameter 1.2mm, 1.6mm, 2.0mm and length 6.0mm, 8.0mm, 10.0mm, 12.0mm and cortical bone width 1.0mm. Also, another three dimensional finite element models were made of diameter 1.2mm, 1.6mm, 2.0mm and length 8.0mm and cortical bone width 1.0mm, 1.5mm, 2.0mm, 2.5mm, Two-hundred grams horizontal force were applied on the center of the miniscrew head and at that stress distribution and its magnitude had been analyzed by ANSYS, which is three dimensional finite element analysis program. The obtained results were as follows : 1. The comparison of the maximum von-Mises stress in the miniscrew showed that as the diameter increases from 1.2mm to 2.0mm stress has been decreased, while on the same diameter stress was not changed regardless of the length change. 2. The comparison of the maximum von-Mises stress in the cortical and cancellous bone showed that as the diameter increases from 1.2mm to 2.0mm stress has been decreased, while on the same diameter stress was not changed regardless of the length change. 3. In the analysis of the stress distribution in the cortical and cancellous bone, the most of the stress had been absorbed in the cortical bone, and did not transmitted much to the cancellous bone. 4. In the analysis of the maximum von-Mises stress according to the cortical bone width, the same diameter of the miniscrew showed a constant stress value regardless of the cortical bone width change. The above results suggest that the maintenance of the miniscrew is more reliable on diameter than length of the miniscrew.