不同垂直骨面型成人上下颌后牙区皮质骨密度测量研究

目的探讨不同垂直骨面型成人上下颌后牙区微螺钉种植体（MSI）常植入部位的皮质骨密度,为临床成功植入MSI提供参考。 方法采用整群抽样的方法从2015年1月至2018年12月广州市花都区妇幼保健院（胡忠医院）口腔正畸科就诊并拍摄锥形束CT（CBCT）的20 ~ 40岁成人患者中抽取57例患者,其中高角组患者20例、均角组患者22例和低角组患者15例。应用Ez3D-i软件重建上下颌骨三维模型,测量上下颌骨12个牙根间部位（距离牙槽嵴顶4 mm处）皮质骨密度（HU值）,运用单因素方差分析（ANOVA）比较3组各测量部位皮质骨密度均数的差异。 结果3组间上下颌后牙区颊侧多数测量部位皮质骨密度差异有统计学意义（P<0.001）,其中高角组最小。上颌腭侧多数测量部位差异无统计学意义。各组中相同牙位上颌后牙区颊侧、腭侧、以及下颌颊侧皮质骨密度差异有统计学意义（P<0.001）,其中上颌腭侧最小,下颌颊侧最大。 结论成人上下颌后牙区颊侧皮质骨密度受垂直骨面型影响,高角成人在上颌后牙区颊侧植入MSI需谨慎;上颌后牙区腭侧皮质骨密度几乎不受垂直骨面型影响,但骨密度低,植入MSI时也需谨慎。     

光相干成像技术对猪上下颌骨缺损探查深度差异的研究

目的：研究频域型光相干成像（ fourier domain optical coherence tomography, FD OCT）系统对猪上、下颌骨缺损探查深度的差异。方法从10对猪同侧上下颌骨第二磨牙区颊侧截取20块骨块,将骨块内侧面打磨成水平面,外侧面保持完整。用锥形车针在内侧面上制备出楔形沟槽,槽内充填肉末模拟骨缺损。频域OCT从骨块外侧面,沿沟槽最深处向最浅处扫描。当沟槽底部在OCT影像上刚刚消失时,在骨块外侧面上标记此位点,并记录该位点到槽底之间的骨厚度（即OCT测量值）记为Ls。再用显微CT扫描骨块,测量标记位点到槽底之间骨厚度并记录为Lr。结果频域OCT在猪上、下颌骨骨下缺损探查的平均深度分别为0.86mm和0.78mm,对应OCT测量值分别为1.19mm和1.09mm,两者间均无显著性差异（P＆gt;0.05）。结论在本研究条件下,频域OCT对猪上、下颌骨缺损的探查深度无显著性差异。     

我国北方成年人下颌骨骨密度的测量研究

目的 研究健康人下颌骨与全身骨密度的相关性.方法 选择中国北方健康志愿者221名,分别将不同性别的志愿者按年龄分为6组,即≥20岁(男21人、女23人)、≥30岁(男20人、女21人)、≥40岁(男21人、女22人)、≥50岁(男20人、女21人)、≥60岁(男16人、女15人)、≥170岁(男11人、女10人).从每人下颌骨颏部及双侧下颌角各选10个感兴趣区,用双能X线骨密度仪测量骨密度值,同时测量腰椎(L2-L4);并行统计学分析.结果 该人群的下颌骨颏部的骨密度值为(1.310 9±0.035 5)g/cm2,左下颌角的骨密度值(1.048 9±0.013 7)g/cm2,右下颌角的骨密度值(1.054 7±0.014 1)g/cm2,腰椎(L2-L4)的骨密度值(1.1211±0.0172)g/cm2.男女之间下颌角、腰椎的骨密度比较,差异有统计学意义(t(左)=2.017 5,t(右)=2.446 9,P<0.05).50岁以后下颌角、腰椎的骨密度明显减低.结论 下颌骨与腰椎的骨密度密切相关,下颌骨可以作为测量全身骨密度的一个敏感部位进行骨质疏松的预测.     

Comparison of malignant tumors and sinusitis of maxilla on CT images: Sites of bone destruction

We used CT to examine the bone destruction sites of the entire bone wall of the maxillary sinus in cases of malignant tumors of the maxilla and in maxillary sinusitis cases to investigate the differences between the destructive findings of the bone of both patient groups. The study subjects consisted of 13 patients with malignant tumors of the maxilla and 45 patients with maxillary sinusitis. Destruction of the bone wall was seen in 100% of the patients with malignant tumor of maxilla patients and in 57.8% with the maxillary sinusitis, hence showing a significantly higher incidence in malignant tumors of the maxilla. Neither group of patients exhibited disease-specific characteristics of their bone destruction. The incidence of posterolateral bone destruction in patients with malignant tumor of the maxilla patients was 61.5%, while it was significanty lower at 23.1% in the maxillary sinusitis patients. The number of bone walls affected was 2 or more walls in 84.5% of the malignant tumor patients of the maxilla patients and in 42.3% of the maxillary sinusitis patients.     

Racial disparity of Crouzon syndrome in maxilla and mandible

The racial disparity of facial features in craniosynostosis patients is not fully understood. The aim of this study was to explore the difference in maxillary and mandibular morphology and spatial position in Asian and Caucasian Crouzon syndrome patients. Ninety-one computed tomography scans were included (12 Asian Crouzon syndrome patients, 22 Asian controls; 16 Caucasian Crouzon syndrome patients, 41 Caucasian controls) and measured using Materialise software. The maxillary and mandibular volumes of Asian patients were both reduced by 19% (P = 0.102 and P = 0.187), and those of Caucasian patients were reduced by 15% (P = 0.142) and 14% (P = 0.211) when compared to the respective race-specific controls. Maxilla length of Asian patients was reduced by 6.36 mm (14%, P = 0.003), while the reduction in Caucasian patients was 4.88 mm (10%, P = 0.038). ANS was retracted 11.99 mm (P < 0.001) in Asian patients and 11.54 mm (P < 0.001) in Caucasian patients. The ANB angle was narrowed by 13.17° (P < 0.001) in Asian patients compared to Asian controls, and by 7.02° (P < 0.001) in Caucasian patients compared to Caucasian controls. The retrusive midface profiles of Asian and Caucasian Crouzon syndrome look similar; both result from the combined effect of hypoplastic size and backward displacement. However, the insufficiency was found to be more a failure of the anteroposterior maxillary length in Asian patients, and more due to posterior maxillary positioning in Caucasian patients. Therefore, prognathism in Crouzon syndrome patients is more likely caused by displacement rather than elongation of mandibular length in both races. Crouzon syndrome results in the same extent of overall volume deficiency of the maxilla and mandible in these races.     

Management of juvenile ossifying fibroma in the maxilla and mandible

We present three cases with juvenile ossifying fibroma. Two occurring in the maxilla, and one in the mandible. All three cases presented with a major swelling in the face. After clinical and radiological evaluation the lesions were surgically excised and sent for histopathological evaluation. Two histological types of juvenile ossifying fibroma were found, the psammatous type in two cases and the trabecular pattern in one case. Although juvenile ossifying fibroma is an uncommon clinical entity, its aggressive local behaviour and high recurrence rate mean that it is important to make an early diagnosis. It is also important to apply the appropriate treatment and to follow-up the patient closely over the long term. This report describes the diagnosis and treatment of juvenile ossifying fibroma in the maxilla and the mandible. It also emphasizes the importance of considering the less aggressive options as a first line of treatment before choosing the aggressive approach when dealing with children.     

Quantitative assessment of post-extraction healing and alveolar ridge remodelling of the mandible in female rats

OBJECTIVE: To quantitatively evaluate the healing and bone changes in the mandible of adult female rats following unilateral extraction of the mandibular molars and the incisor. METHODS: Six-month old female rats had their mandibular molars and the incisor on one side of the mandible extracted. Nine rats were sacrificed at 0, 14, 28, 56 and 112 days post-extraction. Bone mineral density (BMD) as observed by dual energy X-ray absorptiometry (DEXA) and histomorphometric measurements of total bone volume (TBV/TV%) as well as changes in size; height and width on backscattered electron microscopy images of cross-sections of the mandible were evaluated. RESULTS: There was a total increase of 28% in BMD of the body of the mandible and 35.1% increase in TBV/TV% at 112 days post-extraction. A maximal increase of 25% in BMD was observed at 14 days post-extraction. TBV/TV% increased by 9.5% at 14 days post-extraction and further increased by 15.9% (P < 0.001) from 14 to 28 days and by 9.2% (P < 0.001) from 28 to 56 days. A further slight but non-significant increase of 6% (P = 0.108) occurred from 56 to 112 days post-extraction. Regression equations demonstrated that the maximal increase in TBV/TV% and BMD occurred between 0 and 28 days, which subsequently slowed down between 28 and 56 days and further declined between 56 and 112 days post-extraction. Healing was associated with a reduction in cross-sectional area (32.89%), height (21%) and width of the mandible (12.84%). CONCLUSIONS: BMD of the edentulous mandible following extraction of mandibular molars and the incisor on one side of the mandible increases up to 56 days, but that total bone volume increases up to 112 days post-extraction. This indicates that bone volume measurement is more sensitive than BMD measurements in detecting small increase in bone formation at later stages of healing, possibly because of changes in geometry of the edentulous mandible following teeth extraction. The edentulous mandible undergoes a significant reduction in size as a result of reduction in both height and width up to 112 days post-extraction.     

应变率和骨密度对人下颌骨拉伸力学性能的影响

目的 探讨应变率和骨密度与下颌骨位伸力学性能的关系,建立下颌骨在拉伸载荷下的本构方程。方法 以５具新鲜男性青年尸体的下颌骨为材料,对每具标本进行骨密度测试,然后标准试件在Ｉｎｓｔｒｏｎ材料试验机上进行电子拉伸,应变率分别为０．０００３／ｓ、０．００３０／ｓ、０．０３００／ｓ、０．３０００／ｓ,获得不同载荷下相应的应力－应变曲线。利用模型Ｙ＝ａρｂεｃ,以极限强度、弹性模量及破坏应变为因变量（Ｙ）,以应变率和骨密度为自变量（Ｘ）进行非线性回归分析,并建立与应变率和骨密度相关的下颌骨拉伸本构方程。结果 极限强度、弹性模量以及破坏应变相对于应变率和骨密度的非线性方程分别为σｕ＝１２６．３６ρ＾１．８８ε＾０．０４４（Ｐ〈０．０１）、Ｅ＝２５１７０．９７ρ＾０．９６ε＾０．０５６ε＾０．８０（Ｐ〈０．０１）。结论 应变     

老年性骨质疏松症患者下颌骨骨密度的检测分析

目的 研究老年性骨质疏松症患者下颌骨骨密度的改变,探讨下颌骨骨密度改变与全身骨密度改变的相关性.方法 对加例老年性骨质疏松症患者(A组)、40名非骨质疏松症老年志愿者(B组)和40名青年健康志愿者(C组)摄取标准化数字曲面体层X线片;应用计算机图像处理软件对标准化数字曲面体层X线片的下颌骨下缘皮质骨厚度、曲面体层下颌指数、牙槽骨骨密度、牙槽骨骨高度进行测量.使用双能X线吸收骨密度仪测量腰椎及髋关节骨密度.结果 A组下颌骨下缘皮质骨厚度(3.57±0.82)与全身骨密度显著相关(P＜0.05).A组与C组标准化数字曲面体层X线片测量指标(下颌骨下缘皮质骨厚度、曲面体层下颌指数、牙槽骨骨密度、牙槽骨骨高度)差异均具有统计学意义(P＜0.05);A组下颌骨下缘皮质骨厚度(3.57±0.82)与曲面体层下颌指数(0.29±0.06)与B组(下颌骨下缘皮质骨厚度:4.07±0.75,曲面体层下颌指数:0.32±0.07),差异有统计学意义(P＜0.05);B组牙槽骨骨密度(105.40±20.48)与牙槽骨骨高度(10.42±1.82)与C组(牙槽骨骨密度:117.10±22.23,牙槽骨骨高度:11.69±1.63)差异具有统计学意义(P＜0.05).结论 老年性骨质疏松症患者下颌骨下缘皮质骨丢失明显,骨质疏松症对健康牙槽骨没有显著影响,其牙槽骨骨丢失主要为一种增龄性改变.     

锥形束CT对微螺钉前牙根间植入区骨量的分析

目的 通过对微螺钉种植支抗前牙根间植入区骨量进行三维测量分析,为前牙根间植入位点的选择提供参考.方法 对36名成人患者的上、下颌前牙区行锥形束CT扫描及三维重建,分别测量U/L11(上/下颌中切牙根间),U/L12(上/下颌中切牙和相邻侧切牙根间),U/L23(上/下颌侧切牙和相邻尖牙根间)距上、下前牙釉牙骨质界3mm、5 mm、7 mm及9mm水平的根间距(D1)和牙槽骨宽度(D2).采用SPSS 17.0软件进行单因素方差分析和Duncan法进行两两比较.结果 相邻两牙根间最小距离D1:从大到小依次为U11＞U23＞L23＞L11＞U12＞L12,所有牙位越往根尖方向D1越大,其中只有U11,U23分别距离釉牙骨质界5mm和7mm根间距大于3mm,相邻两牙根间唇舌向牙槽骨宽度D2为:U11＞L11,U12＞L12,L23＞U23,不同水平D2值在3.82～6.62mm之间.结论 上、下颌前牙区,上颌中切牙之间及上颌侧切牙和尖牙之间的根间区是植入微种植体较理想的部位.     

Ramsay-Hunt syndrome complicating osteonecrosis of edentulous maxilla and mandible: report of a rare case

Review of literature revealed atleast 30 cases of post herpes zoster osteonecrosis of maxilla or mandible. To our knowledge this is a first reported case of Ramsay-Hunt syndrome with post herpetic neuralgia and post herpes zoster osteonecrosis of edentulous maxilla and mandible. We have briefly reviewed the pathophysiology and management of post herpes zoster osteonecrosis and post herpetic neuralgia.     

有牙颌与无牙颌老年人下颌及髋部骨密度的比较研究

目的　观察有牙颌与无牙颌老年人下颌骨及髋部骨骨密度有无差别 ,探讨影响牙槽骨骨吸收及无牙颌发生的全身危险因素。方法　采用双能X线吸收法测量全部研究对象的右侧髋部骨密度及左侧下颌角骨密度。结果　无牙颌与有牙颌老年人相比 ,前者下颌角骨密度较低 (P <0 0 0 1) ;髋部 (股骨颈、大粗隆、Ward三角区 )骨密度也表现出不同程度的降低。结论　髋部或全身骨密度减低、下颌骨骨密度减低是导致牙齿缺失及无牙颌的因素之一。     

实验性咬合功能减退及功能恢复对大鼠下颌骨骨矿密度的影响

目的:探讨实验性咬合功能减退及咬合功能恢复对大鼠下颌骨骨矿密度的影响。方法:60只雄性SD大鼠,随机等分为咬合功能减退组、咬合功能恢复组和空白对照组。于实验开始时(0周)和第2、4、6、8周麻醉下处死动物,测量大鼠体重,并用Micro-CT测量下颌第一磨牙区域松质骨和皮质骨的骨矿密度(BMD)。采用SPSS12.0软件包对数据进行统计学处理。结果:与对照组相比,咬合功能减退组大鼠根分叉区和根尖区松质骨BMD于实验4周后降低(P<0.05),颊、舌侧松质骨BMD于实验6周后开始降低(P<0.01),且均持续到实验结束(P<0.01);咬合功能恢复组大鼠在第8周时除根分叉区外(P<0.05),根尖区及颊、舌位点松质骨BMD恢复至正常水平,高于咬合功能减退组(P<0.01);在第6周和第8周时,咬合功能减退组大鼠舌侧中部和基底区皮质骨BMD较对照组降低(P<0.05),而咬合功能减退组大鼠颊侧以及咬合功能恢复组大鼠颊、舌侧皮质BMD与对照组无显著差异。结论:咬合功能减退可导致大鼠下颌骨松质骨和皮质骨BMD的降低,咬合功能恢复可逆转下颌骨骨矿密度的减少。     

Two alternative surgical techniques for enhancing primary implant stability in the posterior maxilla: a clinical study including bone density, insertion torque, and resonance frequency analysis data

Background: The primary stability of dental implants associated with resistance to micromotion during healing is affected by surgical technique and implant design, which are important especially in the soft bone, where implant failures are more likely. Purposes: This study was designed to compare the parameters associated with implant insertion using two different methods of enhancing implant primary stability and to identify any relationship between these parameters at implant insertion. Materials and Methods: A total of 60 implants were placed in the maxillary posterior regions of 22 patients. The bone densities at the implant sites were recorded using a computerized tomography machine in Hounsfield unit (HU). The maximum insertion torque data were recorded with the Osseocare™ (Nobel Biocare AB, Göteborg, Sweden) equipment, while resonance frequency analysis (RFA) measurements were taken using an Osstell™ (Integration Diagnostics AB, Göteborg, Sweden) machine at implant surgery. Comparisons including HU, Ncm, and implant stability quotient were made between two control groups (C1 and C2), and corresponding four test groups (T1–T4) using thinner drills to enhance primary implant stability. Results: Two implants were lost, meaning an overall implant survival rate of 96.6% after 3 ± 1 years. When compared to control groups, significantly higher mean maximum insertion torque and RFA values were found for corresponding test groups. In addition, strong correlations were observed between the bone density and insertion torque, and implant stability values at implant placement. Conclusion: The results of this study suggest that using thinner drills for implant placement in the maxillary posterior region where bone quality is poor may improve the primary implant stability, which helps clinicians to obtain higher implant survival rates.     

Large peripheral osteoma of the mandible

This case report concerns a 30-year-old man who presented with a large mass on the left side of the jaw in the submandibular area. Panoramic radiography and computed tomography revealed the swelling to be a peripheral osteoma of the mandible, which was excised surgically.     

Correlation of cone beam CT-derived bone density parameters with primary implant stability assessed by peak insertion torque and periotest in the maxilla

Purpose

Primary implant stability is crucial to osseointegration. The aim of this study was to assess correlation of preoperative radiologic parameters with intraoperatively obtained biomechanical tests in the maxilla.

Mandibular bone stiffening and increased bone calcium mass in rats permanently stunted by hypophysectomy

OBJECTIVE: This investigation was designed to obtain information on the changes induced by hypophysectomy on biometric parameters, bone calcium mass, and material and architectural properties during ontogenesis of the rat mandible. DESIGN: Female Sprague-Dawley rats were hypophysectomised (HX) at 30 days of age. A "basal control group" (BC) was sacrificed on the same day surgery was performed. An "age-matched intact control group" (CON) was also included. HX and CON rats were sacrificed when aged 6 months. Body weight was monitored weekly. Mandibular growth was estimated directly on the right hemimandible by taking measurements between stable anatomical points. Its mechanical properties were determined using a three-point bending mechanical test. Load was applied transversely to the bone axis at a point immediately posterior to the posterior surface of the third molar. The left hemimandibles were ashed in a muffle furnace at 600 degrees C for 18h and the ash weight obtained. Calcium content in the ashes was determined by atomic absorption spectrophotometry. It was taken as the mandibular calcium mass. Histomorphometric studies were performed on decalcified hemimandibles: total interradicular bone, bone volume, and height of the periodontal ligament were measured. CONCLUSIONS: Morphometric studies indicated that hypophysectomy in juvenile rats induced mandibular growth cessation, which was limited to the posterior part of the bone. Thus, the mandible maintained its juvenile proportions and showed an important deformation relative to age. In spite of the reduced bone size, both the mandibular weight and the calcium bone mass increased more than two times in ontogenia. Histomorphometric studies revealed that the interradicular bone volume was markedly increased. These findings strongly suggest that the bone that forms the mandible of the hypophysectomised rat under the conditions of the present study showed a higher than normal density. As evidenced from biomechanical studies, these bone properties, plus the significant stiffening of bone material tissue, were presumably responsible for the unnecessary and marked increment in the "load capacity" suffered by the mandible of the hypophysectomised rat during ontogenesis.     

Metastasis of colon adenocarcinoma to the mandible: A case report

Metastatic tumors to the oral cavity are uncommon. In this article, we report a case of metastatic adenocarcinoma of the colon to the mandible with imaging features. A 73-year-old man with a history of colon cancer and liver metastasis was referred to our hospital with a chief complaint of swelling and pain in the right mandible. Panoramic radiograph revealed a radiolucency with ill-defined margin. Computed tomography showed an osteolytic lesion with cortical bone destruction. Magnetic resonance imaging showed a round-shaped homogeneous intensity mass expanding from the mandible. Histopathological diagnosis revealed metastatic adenocarcinoma of the colon.