去势大鼠骨质疏松模型的综合评定

目的：多种方法评定大鼠去除双侧卵巢三个月后是否形成明显骨质疏松状态。方法：分别从6月龄SD雌性大鼠假手术对照（Sham）组和卵巢切除骨质疏松（0VX）组各取大鼠8只。将全部大鼠取血后处死。取一侧胫骨、股骨,去净软组织。分别行血生化骨代谢指标检测、MicroCT检查、骨组织计量学测量及组织病理学观察、三点弯曲试验。所得数据经SPSS13．0统计分析。结果：OVX组大鼠ALP、OC较Sham组明显升高,P〈0．05。骨小梁数目减少,排列稀疏,骨小梁断裂;骨小梁面积比和体积比、厚度和数目,骨矿含量和骨体积密度等均较Sham组显著降低,骨小梁分离度增加,P〈0．05。OVX组弹性载荷与Sham组升高明显,P〈0．05;最大应力和弹性应力显著降低P〈0.05。结论：经多种方法评定,3月龄SD雌性大鼠切除卵巢3月后,形成明显骨质疏松状态。OVX大鼠,骨量降低,骨小梁结构改变,骨生物力学性能变差。     

雌激素对去势大鼠颌骨和股骨结构影响的实验研究

目的 :观察雌激素对实验性骨质疏松大鼠颌骨和股骨结构影响的相互关系。方法 :切除SD雌性大鼠双侧卵巢建立骨质疏松动物模型 ,给予腹腔注射雌二醇 ,治疗 6周后处死大鼠 ,取颌骨和股骨标本 ,对组织切片进行骨组织形态计量学分析。结果 :去势后的大鼠颌骨、股骨骨小梁呈疏松化改变 ,股骨骨量减少明显多于颌骨 ;雌二醇治疗后可明显抑制颌骨、股骨骨质的吸收 ,颌骨骨量变化更为明显。结论 :雌激素治疗对于骨质疏松的颌骨、股骨骨小梁结构的影响是有差异的 ,治疗效果颌骨优于股骨 ,可能与扁骨、长骨本身结构和功能不同有关     

大鼠卵巢去势后颌骨与全身骨的形态学研究

目的：本实验通过切除大鼠双侧卵巢，观察颌骨的结构变化，了解其与全身骨结构变化的关系。方法：SD雌性大鼠4月龄行双侧卵巢切除术，术手3个月处死收取标本，进行HE染色，光镜观察，结果：切除卵巢后胫骨松质骨改变明显，牙槽骨仅个别密质骨见到活动性骨吸收，固有牙槽骨，松质骨及髁状突未见明显的改变。结论：大鼠卵巢去势后全身骨骼的骨结构的形态学改变明显，而颌骨骨结构的形态改变不明显。     

“骨疏康”对去势大鼠下颌骨骨量变化的影响

目的 :观察防治骨质疏松症的药物“骨疏康”如何影响下颌骨的骨量变化。方法 :以去势大鼠 (Ovariectomizedrats,OVX)为绝经后骨质疏松症模型以诱发下颌骨骨丢失 ;对去势大鼠分别以“骨疏康”一代、二代 (2 .5g/kg/day)进行灌胃。结果 :“骨疏康”一代和二代均可抑制去势大鼠下颌骨骨量丢失和骨小梁结构破坏 ,使下颌骨骨密度、骨组织形态计量学指标维持在假去势组 (Sham OVX)水平。结论 :本研究表明防治骨质疏松症药物不仅对全身骨起作用 ,对预防下颌骨骨丢失也有一定的作用。     

辛伐他汀对去势大鼠骨生长代谢的影响

目的:观察辛伐他汀对去势大鼠骨密度和骨生长代谢的作用。方法:40只雌性SD大鼠随机分成4组,正常对照假手术组(Sham)-A,单纯去势组(OVX)-B,去势雌激素治疗组-C;去势辛伐他汀治疗组-D。术后第30天,C组以体质量每100g每天给0.1mg尼尔雌醇灌胃,每周1次,持续12周。D组以辛伐他汀5mg/(kg·d)灌胃,连续服用1周,停2周,再服用1周,间断持续12周。用药12周后,所有大鼠被处死采取胫骨标本,处死前第12和第4天进行四环素双标记。标本行不脱钙骨切片,硝酸银和VonKossa染色,骨形态计量学方法检测各治疗方法对胫骨近心端干骺的作用效果。结果:单纯去势组(OVX)-B与对照假手术组(Sham)-A相比,其胫骨有明显的骨质疏松表现。与OVX相比,雌激素组、辛伐他汀组去势大鼠胫骨骨形态计量学静态参数%Tb.Ar、Tb.N,Tb.Sp有明显差异(P<0.01)。辛伐他汀组的动态骨形成参数%L.Pm、MAR、BFR/BV、%O.Pm及荧光双标间隔均明显高于其他各组(P<0.01),骨吸收参数Oc.N、%E.Pm低于单纯去势组,但高于雌激素组和假手术组(P<0.01),雌激素组骨吸收参数Oc.N、%E.Pm相对单纯去势组显著下降(P<0.01)。结论:辛伐他汀能降低大鼠去势后骨转换,促进骨的生长,并能抑制骨的吸收作用。     

1α（OH）—D3对去势大鼠下颌骨骨量变化的影响

评价防治骨质疏松症药物１α（ＯＨ）－Ｄ如何影响下颌骨的骨量变化。。方法以去势大鼠作为绝经后骨质疏松症模型以诱发下颌骨骨丢失。对去势大鼠分别以０．０４μｇ／ｄａｙ、０．５μｇ／ｋｇ／ｄａｙ两种不同浓度进行灌胃。结果１α（ＯＨ）－Ｄ３可抑制去势大鼠下颌骨骨丢失和骨小梁结构破坏,下颌骨骨密度、骨组织形态计量学指标维持在假去势组水平。结论防治骨质松站药不仅对全身骨起作用,对预防下颌骨骨丢失也有一定的效果。     

雌激素和应力环境改变对骨质疏松大鼠下颌骨骨小梁结构的影响

目的: 探讨骨质疏松状态下由于牙齿缺失后应力环境的改变,导致下颌骨骨小梁结构的变化及补充雌激素对其变化的影响。方法: 用去势法建立骨质疏松的大鼠动物模型,8周后拔除大鼠单侧所有上颌磨牙,模拟下颌骨高低应力环境的变化,用骨组织形态计量学的方法观察骨质疏松组、雌激素治疗组和假手术对照组双侧下颌骨骨小梁的变化。结果: 骨质疏松组低应力侧比高应力侧的Tb.Ar、Tb.Wi明显降低(P<0.01),Tb.Sp明显增大(P<0.05);正常组和雌激素组无明显差异;雌激素组高应力侧、低应力侧的Tb.Ar与骨质疏松组同期相比增大(P<0.05)。结论: 高应力可减缓骨质疏松所引起的下颌骨骨小梁的吸收,低应力则可加速骨吸收;雌激素的补充治疗阻止了去势后大鼠下颌骨骨质的吸收,并抑制低应力环境下颌骨的进一步丢失,促进了骨形成。     

1α(OH)-D_3对去势大鼠下颌骨骨量变化的影响

目的　评价防治骨质疏松症药物 1α(OH) -D3 如何影响下颌骨的骨量变化。方法　以去势大鼠作为绝经后骨质疏松症模型以诱发下颌骨骨丢失。对去势大鼠 (ovariectomizedrats,OVX)分别以 0 .0 4μg/kg/day、0 .5μg/kg/day两种不同浓度进行灌胃。 结果　 1α(OH) -D3 可抑制去势大鼠下颌骨骨丢失和骨小梁结构破坏 ,下颌骨骨密度、骨组织形态计量学指标维持在假去势组 (Sham -OVX)水平。结论　防治骨质疏松症药物不仅对全身骨起作用 ,对预防下颌骨骨丢失也有一定的效果     

下颌骨牵张成骨过程中新骨生成的定量组织学观察

目的：对下颌牵张成骨过程中的新骨生成进行动态定量组织学观察,探讨下颌牵张成骨过程中新骨生成的规律。方法：采用牵张成骨术延长10只山羊双侧下颌骨10mm,于术后第10、15、25、35和45天各处死2只动物;另选取2只山羊．不实施手术作为正常对照组。用骨组织形态法评价新生骨组织的形态结构变化;用四环素荧光标记法间接测定新骨的中成速率．外用方置分析法对数据进行统计学分析。结果：从10天组到45天组的平均骨小梁体积分数、平均骨小梁厚度、平均骨小梁数目和新生骨小梁体积密度比均表现为向正常对照组阶梯式递增（P〈0．05）,而平均骨小梁分隔距离和新生骨小梁表而积密度则表现为向正常对照组阶梯式递减（P〈0．05）。从15天组到45天组,成骨细胞活性均显著高于正常对照组（P〈0．05）;而破骨细胞活性则表现为向正常对照组阶梯式递增（P〈0．05）。从15天组到45天组,新骨生成速率与正常对照组相比有3个数量级的差异（P〈0．05）。结论：在下颌骨牵张过程中,新生骨小梁由少到多,从幼稚到成熟：新骨生成过程持续活跃：骨吸收改建过程逐渐增强：牵张期新骨生成速率快于固定期。     

骨挤压技术对去势大鼠种植后骨整合的影响

目的 从组织学角度观察骨挤压技术对于去势所致骨质疏松症大鼠行种植后骨整合的影响。方法 72只3月龄SD大鼠随机分为2组，一组36只行去势（Ovx）手术。另一组作为对照组行假手术。120天后测量大鼠体重及骨密度，确定建立骨质疏松大鼠模型。处死对照组，将原试验组36只大鼠作为新的研究对象随机分为实验组和对照组，每只大鼠胫骨近骺端植入纯钛种植体。实验组经过骨挤压，对照组不经骨挤压。分别于术后28天、56天、84天处死动物、取材。切片进行光学显微镜观察和骨计量学测量。结果 28天和56天实验组骨结合率与对照组相比有显著性差异，84天时两组无显著性差异。结论 经过骨挤压后的实验性骨质疏松大鼠骨整合更具优势。     

应用Micro CT进行下颌骨骨板厚度的测量研究

目的：运用MicroCT测量下颌骨牙根尖到颊侧骨板的解剖距离。方法：应用Micro CT（Skyscan1072,Antwerpen,Belgium）及cutome软件分析下颌骨三维骨结构。结果：下颌第二磨牙远中根到颊侧骨板的平均距离为8.51mm,近中根距离7.34mm,融合根7.19mm。下颌第一磨牙近中和远中根到颊侧骨板的距离分别为5.18mm和4.09mm。当出现有2个远中根时,远中舌侧根到颊侧骨板的厚度约9.52mm。第一前磨牙和第二前磨牙到颊侧骨板的平均距离分别为3.68mm和3.02mm。前牙牙根到颊侧骨板的距离2.07mm～2.48mm。男性下颌骨颊侧骨板厚度大于女性,差异没有统计学意义（P〉0.05）。结论：Micro CT是一种快速、准确、不损伤样本内部结构的有效的评价方法。牙根尖到下颌颊侧骨板厚度的测量结果可为牙根尖手术和牙种植术提供理论依据。     

Effect of calcium supplementation on bone dynamics of the maxilla, mandible and proximal tibia in experimental osteoporosis

The effect of calcium supplementation on the bone dynamics in the hard palate of the molar region (maxilla), mandible and proximal tibia in experimental osteoporotic rats was examined. Ninety ovariectomized (OVX) and 45 sham-OVX Wistar female rats were used in this study. All the rats received surgical operation at 6 weeks of age. Ovariectomized rats were fed on a low calcium diet (0.02%) for 12 weeks post-operation, and then randomly divided into the two following groups. One group was fed on high calcium diet (2.30%) (OVX-HCa) and the other group was remained on the low calcium diet (OVX-LCa). Sham-OVX rats were fed on regular calcium diet (1.15%) during the experimental period (Sham-OVX). Histomorphological analysis was carried out from 12 to 32 weeks post-operation. On undecalcified thin section, bone volume, eroded surface, osteoid surface and bone formation rate were calculated for cortical bone of the maxilla, and for cancellous bone of the mandible and proximal tibia. In the OVX-LCa group, compared with the Sham-OVX group, decrease of the bone volume and increase of the bone resorption and formation parameters were detected throughout the observation periods. In the OVX-HCa group, compared with the OVX-LCa group, increase of the bone volume and temporarily increased parameters of bone formation at 1 week after feeding on high calcium diet were observed in the maxilla, but these changes were not observed in the mandible and proximal tibia. Moreover, the bone resorption and formation parameters in the maxilla, mandible and proximal tibia in the OVX-HCa group became equivalent to the Sham-OVX levels with the passage of time.     

Cortical porosity of the mandible in an osteoporotic sheep model

Objectives: Cortical porosity and thickness of the axial and the appendicular skeleton are predictors of osteoporotic fractures. In the jawbone, however, cortical porosity and thickness may affect the mechanical stability of dental implants. We have shown previously that the jawbone of osteoporotic sheep has impaired trabecular structures, but whether catabolic bone turnover also accounts for the cortical bone porosity remains unknown. Material and methods: We compared mandibular bone from six geriatric sheep subjected to ovariectomy, calcium/vitamin D restriction, and methylprednisolone administration to those of six healthy adult control sheep. Histological ground sections were prepared from the diastema, first and second premolars, and postmolar region. Cortical porosity and thickness were assessed by histomorphometry. Results: Cortical porosity was higher in osteoporotic sheep than in adult controls in the diastema and in the first and second premolar region. In the postmolar region, the difference failed to reach the level of significance. The changes were even more prominent when histomorphometry was restricted to the inner millimeter of the mandibular cortex. In contrast, induction of osteoporosis did not have a discernable effect on cortical thickness. Conclusion: These results demonstrate that cortical porosity of mandibles is more pronounced in geriatric osteoporotic sheep than in adult controls. To cite this article:
Dvorak G, Reich KM, Tangl S, Goldhahn J, Haas R, Gruber R. Cortical porosity of the mandible in an osteoporotic sheep model.
Clin. Oral Impl. Res 22 , 2011; 500–505
doi: 10.1111/j.1600‐0501.2010.02031.x     

Effects of ovariectomy on trabecular structures of rat alveolar bone

An association between postmenopausal osteoporosis and tooth loss has been proposed. However, histomorphometrical changes in alveolar bone following estrogen deficiency are rarely reported with data on microtrabecular structural changes. To clarify the relationship between estrogen deficiency and tooth loss, we histomorphometrically analyzed the trabecular structural changes of mandibular alveolar bone in ovariectomized rats. Twenty-four adult female Fischer rats were used. Eight rats were sacrificed on day 0 (baseline). The remaining 16 rats were divided into two groups. One group was ovariectomized bilaterally (OVX) and the other group was subjected to sham surgery (Sham). After administration of tetracycline and calcein, the animals were sacrificed 60 days after surgery. Bone histomorphometry, node-strut analysis and measurement of thickness of alveolar bone proper were performed on the interradicular septum of the first molar on the sagittal surface. The trabecular bone volume and trabecular number of the OVX group were significantly lower than those of the baseline and Sham groups. All of the bone resorptive and formative parameters of the OVX group were significantly higher (about one-and-a-half times) than those of the Sham group. Several osteoclasts were seen lining the irregular, eroded surface facing the bone marrow in the OVX group. Furthermore, the OVX group tended to have low microtrabecular stiffness and showed significantly thinner distal alveolar bone proper than in the baseline and Sham groups. In summary, estrogen deficiency caused osteoporotic changes and thin alveolar bone proper in the interradicular septum of rat first molar. This phenomenon might accelerate destruction of alveolar bone and tooth loss, especially in elderly women affected by periodontal disease.     

Effect of icariin on bone formation during distraction osteogenesis in the rabbit mandible

The aim of this study was to evaluate the effect of icariin on bone formation during mandibular distraction. 40 Rabbits were randomly divided into experimental and control groups. Mandibular distraction was performed 5 days after unilateral mandibular osteotomy using a custom-made external distractor at a rate of 0.5 mm/12 h for 10 days. From the first day of distraction, icariin (2.5 mg/kg·day) was orally administered to the experimental group and placebo to the controls. 10 Rabbits were killed at the end of weeks 2 and 4 of the consolidation phase. The distracted hemimandible was harvested and newly formed bone was evaluated by soft radiography, histology and bone histomorphometry. Regenerated bone was evaluated for bone mineral density by dual-energy X-ray absorptiometry. The experimental group had fewer radiolucent areas on soft radiography. Bone mineral density of regenerated bone was higher in the experimental than in the control group at 2 and 4 weeks. At 4 weeks, the experimental group had greater volumes of new bone, higher trabecular number, and less trabecular separation than the controls. Oral administration of icariin could promote bone formation during mandibular distraction osteogenesis and might be a promising method for shortening the course of distraction osteogenesis.     

Study of mandible bone mineral density of Chinese adults by dual-energy X-ray absorptiometry

The objective of this study was to measure the bone mineral density (BMD) of mandible and study the correlation between the BMD of the mandible and the lumbar vertebrae. 224 healthy volunteers were recruited in China and divided into 6 age groups: 20-29, 30-39, 40-49, 50-59, 60-69, and over 70 years. Dual-energy X-ray absorptiometry (DXA) was used to measure the BMD of the lumbar vertebrae and the mandible of each volunteer. The BMD of mandibular chin, mandibular angle and the lumbar vertebrae (L1-L4) was 1.3013 ± 0.2576 g/cm², 1.0484 ± 0.1087 g/cm² and 1.1195 ± 0.1373 g/cm², respectively. The BMD of mandibular angle and lumbar vertebrae decreased significantly beyond the age of 50 years. There was a significant difference between males and females in the BMD of the mandibular angle and lumbar vertebrae in the 50-59, 60-69 and over 70 year age groups. The authors found that the BMD of mandibular angles correlates with that of lumbar vertebrae. This study suggests that measurement of mandible BMD could be used to predict osteoporosis.     

Quality and quantity of bone following alveolar distraction osteogenesis in the human mandible

PURPOSE: The purpose of this prospective study on humans were to evaluate (a) the clinical outcome of alveolar distraction osteogenesis for the correction of vertically deficient edentulous mandibular ridges, (b) the clinical outcome of dental implants placed in the distracted areas, and (c) the quality and quantity of the bone that had formed in the distraction gap. MATERIAL AND METHODS: Seven patients presenting vertically deficient edentulous ridges were treated by means of distraction osteogenesis with an intraoral alveolar distractor. Approximately 3 months after consolidation of the distracted segments, 20 ITI solid screw SLA implants were placed in the distracted areas. Three to 4 months later, abutments were connected and prosthetic loading of the implants started. During implant site preparation, bone biopsies were taken at the implant sites with trephine burrs for histologic and histometric analyses. RESULTS: The mean follow-up after the initial prosthetic loading was 18 months (range 12-24 months). The mean bone gain obtained at the end of distraction was 7 mm (range 5-9 mm). The cumulative success rate of implants 2 years after the onset of prosthetic loading was 95%, whereas the survival rate of implants was 100%. The newly formed bone consisted of woven bone reinforced by parallel-fibered bone with bone marrow spaces between the bone trabeculae. The bone area fraction in the distraction region ranged from 21.6% to 57.8% (38.5+/-11.7%). DISCUSSION AND CONCLUSIONS: Results from this study showed that (a) distraction osteogenesis is a reliable technique for the correction of vertically deficient edentulous ridges, (b) the regenerated bone withstood the functional demands of implant loading, (c) survival and success rates of implants placed in the distracted areas were consistent with those of implants placed in native bone, and (d) there is sufficient bone volume and maturity in the distracted region for primary stability of the implant.     

The effect of diabetes mellitus on rat mandibular bone formation and microarchitecture

Abbassy MA, Watari I, Soma K. The effect of diabetes mellitus on rat mandibular bone formation and microarchitecture. Eur J Oral Sci 2010; 118: 364–369. © 2010 The Authors. Journal compilation © 2010 Eur J Oral Sci The aim of this study was to assess the effect of type 1 diabetes mellitus (DM) on the structure of mandibular bone and on the changes of alveolar/jaw bone formation. Experimental DM was induced in 3‐wk‐old male Wistar rats by a single dose of 60 mg/kg body weight of streptozotocin. All rats were injected with calcein on days 21 and 28. The rats were killed when 8 wk of age. Bone structure was analyzed by bone histomorphometry, microcomputed tomography (micro‐CT), and histological section. Histomorphometric analysis showed that the mineral apposition and the bone formation rates in most of the mandibular regions were significantly decreased in the DM group compared with the control group. Micro‐CT analysis showed significant deterioration of the bone quality in rats with DM. For a histometric measure of bone resorption, the number of osteoclasts along the distal surface of the alveolar wall was counted. The number of osteoclasts was significantly lower in the rats with DM than in the controls. These findings suggest that uncontrolled DM decreases mandibular bone formation, reduces the rate of bone turnover in the alveolar wall surrounding the root, and affects the quality of bone structure resulting in retardation of its skeletal development.     

儿童下颌骨骨密度的定量CT测量研究

目的 对71名10～16岁儿童的下颌骨骨密度进行定量CT(QCT)测量,探讨骨密度的变化情况.方法 对每名儿童的左侧下颌角、颏中部和右侧下颌角分别进行QCT扫描测量,并按照年龄和性别进行分析.结果 10～12岁儿童左侧下颌角、颏中部、右侧下颌角骨密度平均值分别为44.29、89.70、54.31 mg/dL;13～16岁儿童左侧下颌角、颏中部、右侧下颌角骨密度平均值分别为63.85、122.47、70.23 mg/dL.结论 男性儿童10～12岁组与13～16岁组下颌骨骨密度值随年龄的增加而明显增高,但左右两侧下颌角及颏中部骨密度值有较大差异,男女之间骨密度值也有很大的差异.