不同去势时间大鼠牙槽骨微结构变化的Micro-CT研究

目的： 观察不同去势时间大鼠牙槽骨微结构的改变,探讨去势时间对牙槽骨骨质疏松程度的影响。方法： 健康未孕雌性SD大鼠24只,随机分为去势组(OVX)与假手术组（sham）,每组各12只,分别在全麻下行双侧卵巢去势术与假手术。于术后3个月及6个月2个不同时间点分别处死每组大鼠各6只,取右侧上颌骨标本行Micro-CT扫描;观察去势3个月及6个月后大鼠上颌第一磨牙根分叉区牙槽骨微结构的改变。采用SPSS16.0软件包对数据进行统计学分析。结果： Micro-CT水平面、矢状面二维图像及三维重建均显示,去势3个月及6个月大鼠牙槽骨骨髓腔面积增加、骨小梁变细、部分发生断裂。骨结构参数分析显示,去势3个月及6个月后,大鼠牙槽骨骨密度（BMD）及骨体积分数（BV/TV）、骨小梁宽度（Tb.Th）均显著低于相应时间假手术大鼠（P<0.05）;去势6个月组较3个月组大鼠牙槽骨骨密度(BMD)、骨体积分数(BV/TV)、骨小梁宽度(Tb.Th)显著降低（P<0.05）。去势3个月及6个月大鼠骨小梁数目（Tb.N）及骨小梁分离度（Tb.Sp）显著高于相应假手术组（P<0.05）,且去势6个月组骨小梁数目(Tb.N)显著高于去势3个月组（P<0.05）。结论： 随着去势时间延长,大鼠牙槽骨骨量降低、骨小梁微结构破坏加剧,骨质疏松程度加重。     

甲状旁腺激素与雌激素对去势雌性大鼠牙槽骨代谢的影响

目的 观察甲状旁腺激素与雌激素单独和联合应用对去势雌性大鼠牙槽骨代谢的影响。方法选用4月龄雌性Wistar大鼠66只,分成两组,分别为伪手术组（n=18）和去势组（n=48）。8周后各处死8只证实骨质疏松造模成功。剩余的伪手术组（A组,n=10）Wistar大鼠作为对照;将剩余的去势组Wistar大鼠随机分成4组,分别为去势组（B组）、去势加雌激素组（C组）、去势加甲状旁腺激素组（D组）、去势加雌激素和甲状旁腺激素组（E组）,每组10只。A组和B组注射生理盐水（1 mL·kg-1）;C组注射苯甲酸雌二醇（10 μg·kg-1）; D组注射甲状旁腺激素（20 μg·kg-1）;E组注射苯甲酸雌二醇（10 μg·kg-1）和甲状旁腺激素（20 μg·kg-1）。隔日腹腔注射1次,用药8周。治疗后处死大鼠并测定牙槽骨骨密度,观察每组大鼠骨组织形态计量学参数及血清钙、磷、碱性磷酸酶（ALP）水平。结果去势手术8周后,去势组大鼠牙槽骨密度明显低于伪手术组（P<0.05）。用药8周后,C、D、E组骨密度、骨小梁面积百分比（%Tb.Ar）、骨小梁宽度（Tb.Th）和骨小梁数量（Tb.N）较B组均有明显提高,其中E组提高最明显（P<0.05）。各组血清钙磷值无明显改变（P>0.05）,B组ALP值较A组明显升高（P<0.05）。结论间歇性、小剂量注射甲状旁腺激素能增加去势大鼠牙槽骨的骨密度和改善骨结构,与雌激素联合使用对骨质疏松的治疗有协同作用。     

二膦酸盐对骨质疏松大鼠下颌牙槽骨牙本质基质蛋白1表达的影响

目的 :观察二膦酸盐对去卵巢骨质疏松大鼠下颌牙槽骨内破骨细胞以及牙本质基质蛋白1(dentin matrix protein1,DMP1)表达的影响。方法 :取6月龄SD大鼠30只,随机分为假手术组(Sham)、去卵巢模型组(OVX)和二膦酸盐药物治疗组(RIS),每组10只。Sham组大鼠仅术中暴露卵巢不切除,OVX组大鼠行"双侧卵巢切除术+生理盐水皮下注射",RIS组行"双侧卵巢切除术+利塞磷酸钠(2.4μg/kg)皮下注射"。术后3个月取各组大鼠下颌骨常规脱钙,甲苯胺兰染色观察下颌第一磨牙(M1)区域牙槽骨组织学结构,抗酒石酸酸性磷酸酶(tartrate-resistant acid phosphatase,TRAP)染色观察M1区域牙槽纵隔破骨细胞的骨吸收情况,免疫组化染色观察各组M1牙槽骨DMP1分布表达情况,并进行相关半定量图像分析。结果:与Sham组相比,OVX组TRAP阳性细胞数增加;而较OVX组而言,RIS组TRAP阳性细胞数显著减少(P<0.05)。免疫组化染色显示,各组DMP1不仅表达在牙槽骨骨细胞内,牙槽间隔的松质骨骨基质、牙周韧带中均可见其表达,OVX组M1牙槽骨DMP1表达较Sham组减少(P<0.05),而RIS组表达较OVX组有升高。结论:二膦酸盐能减少骨质疏松大鼠下颌牙槽骨破骨细胞数量,并上调DMP1表达,从而影响下颌牙槽骨矿化。     

利塞膦酸钠对骨质疏松大鼠牙槽骨Bcl-2、BAX表达的影响

目的: 观察利塞膦酸钠对骨质疏松大鼠下颌牙槽骨显微结构、抗凋亡因子Bcl-2、凋亡因子BAX表达以及骨细胞凋亡的影响。方法: 30只6月龄雌性SD大鼠,随机分为3 组（每组10只）,即Sham组（假手术组）、OVX组（接受双侧卵巢切除术）和RIS组（接受双侧卵巢切除术,然后给予利塞膦酸钠）;造模3个月后,取各组大鼠下颌骨进行micro-CT扫描,并通过TUNEL染色以及Bcl-2、BAX免疫组织化学染色检测下颌骨骨细胞的凋亡。采用SPSS 13.0软件包对组间数据进行比较。结果: 与Sham组相比,OVX组牙槽骨丧失和骨细胞凋亡明显增多;RIS组与OVX组相比,骨细胞凋亡显著减少,BV/TV显著增加,Bcl-2 表达增加,Bcl-2/BAX比值增加（P<0.05）。结论: 利塞磷酸钠增加下颌牙槽骨中Bcl-2的表达和Bcl-2/BAX的比值,部分逆转去卵巢骨质疏松大鼠的牙槽骨丧失,减少下颌骨骨细胞凋亡。     

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。     

XW630促进去势大鼠骨组织成骨作用的实验研究

目的 :探讨抗骨质疏松新药XW6 30在去势大鼠骨组织成骨中的作用。方法 :3月龄SD雌性大鼠 36只 ,随机分为 4组 ,即Sham组、OVX组、OVX加雌酚酮组和OVX加XW6 30组 ,每组 3只。术后 30、6 0、90d各处死 1组动物 ,取两侧胫骨作HE和SEM组织学观察 ,取 1侧股骨作三点弯曲力学强度测试。结果 :HE和SEM观察发现 ,OVX组胫骨干骺端术后 30d即呈骨丢失状态 ,并持续至整个观察期。应用雌酚酮和XW6 30治疗后 ,干骺端骨小梁出现不同程度的骨修复现象 ,整个观察期内XW6 30组成骨活动明显较雌酚酮治疗组活跃。整个观察期内 ,OVX组股骨三点弯曲强度呈下降趋势 ,与Sham组存在显著性差异 (P <0 0 1) ,两个治疗组骨强度则呈上升趋势 ,与OVX组存在显著性差异 (P <0 0 5和P <0 0 1)。结论 :XW6 30能有效地促进去势大鼠骨组织的成骨和预防骨质疏松性骨折的发生。     

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。     

蛋白质黏附对镍铬合金在人工唾液中腐蚀行为的影响

目的 研究两种不同蛋白质黏附对镍铬合金在人工唾液中腐蚀行为的影响。方法 实验组中选择小牛血清蛋白（BSA）和溶菌酶（LSZ）作为目标蛋白,分别与人工唾液混合制成不同浓度的试剂,对照组选择纯人工唾液（AS）,将镍铬合金试件分别浸泡在实验组与对照组溶液中24 h,通过测量动电位极化曲线进行拟合,得到电化学腐蚀参数值,包括腐蚀电流值（I_corr）、极化阻抗值（R_p）、破钝电位值（E_br）,以此观察蛋白质黏附对材料腐蚀行为的影响及其与浓度的相关性。结果 BSA组与对照组中测得腐蚀电流值（I_corr）从小到大依次为1% BSA、0.1% BSA、AS、0.01% BSA（P<0.05）,极化阻抗值（R_p）从小到大依次为AS、0.01% BSA、0.1% BSA、1% BSA（P<0.05）,破钝电位值（E_br）从小到大依次为AS、0.01% BSA、0.1% BSA、1% BSA（P<0.05）; LSZ组与对照组中测得腐蚀电流值（I_corr）从小到大依次为AS、0.22% LSZ、0.022% LSZ（P<0.05）,极化阻抗值（R_p）从小到大依次为AS、0.022% LSZ、0.22% LSZ（P<0.05）,破钝电位值（E_br）从小到大依次为AS、0.022% LSZ、0.22% LSZ（P<0.05）。结论 镍铬合金经蛋白溶液作用后,极化阻抗值及破钝电位均显著升高,且蛋白浓度越高,极化抗阻值和破钝电位值升高越显著。     

软食对青春期大鼠下颌后牙区牙槽骨微结构的影响

目的 :观察软食喂养引起的机械负荷改变对青春发育期大鼠下颌后牙区牙槽骨微结构的影响。方法 :取16 d龄雄性SD大鼠20只,随机分为软食组(SD组)和硬食组(HD组),每组各10只。7周后,运用显微CT(Micro CT)技术观察分析2组大鼠下颌第一磨牙(M1)区牙槽骨的松质骨微结构,苏木精-伊红染色对脱钙后的下颌骨M1区域进行组织学观察。结果:Micro-CT结果显示,较HD组而言,SD组M1区松质骨的骨小梁厚度(Tb.Th)显著减少(P<0.01),骨小梁间距(Tb.Sp)显著升高(P<0.05);组织学结果显示,SD组M1牙槽纵隔以及根尖区域骨小梁较HD组稀疏、变细,骨髓腔增大,近牙周韧带区域骨细胞分布减少。结论:软食喂养引起的负荷降低减少了下颌后牙的牙槽骨骨小梁的厚度、增加了骨小梁间距,从而影响了其骨微结构。     

姜黄素对去势骨质疏松大鼠下颌骨和股骨EZH2基因表达的影响

目的 研究姜黄素对去势骨质疏松大鼠下颌骨和股骨EZH2（enhancer of zeste homolog 2,EZH2）表达的影响,探讨其对骨质疏松大鼠的保护作用及机制。方法 将30只6月龄SD雌性大鼠随机分为假手术组（SHAM组）、去势模型组（OVX组）和姜黄素治疗组(OVX+C组)。治疗组将姜黄素溶于羧甲基纤维素钠溶液后,按110 mg/kg·d灌胃给药;假手术组和去势模型组灌胃同等剂量羧甲基纤维素钠溶液,每天1次,连续12周后取材。检测大鼠血清钙、磷、碱性磷酸酶的指标变化,采用Micro-CT对左侧下颌骨和股骨的骨形态计量学参数进行测定。取右侧下颌骨和股骨,采用PT-PCR法检测骨组织EZH2mRNA的表达。采用SPSS22.0软件包对数据进行统计学分析。结果 OVX组骨组织中EZH2mRNA的表达显著高于SHAM组（P<0.05）。与OVX组相比,姜黄素可以改善骨质疏松大鼠的骨微结构,增加骨密度,降低骨质疏松大鼠血清碱性磷酸酶含量,使骨组织EZH2mRNA表达显著下调（P<0.05）。结论 姜黄素能够防治去势大鼠的骨量丢失和改善骨微结构,其机制可能与下调EZH2mRNA的表达水平有关。     

2种给药方式下辛伐他汀对牙周炎骨质疏松大鼠上颌骨骨丢失的影响

目的比较辛伐他汀(Simvastatin,SIM)在不同给药方式下抑制牙周炎骨质疏松大鼠上颌骨骨丢失的作用效果。方法 24只4月龄雌性SD(Sprague Dawley)大鼠,随机分成4组:假手术组(SHAM),去势+绑线组(OVX+LIG),去势+绑线+辛伐他汀灌胃给药组(OVX+LIG+Oral SIM),去势+绑线+辛伐他汀局部用药组(OVX+LIG+Local SIM)。适应性喂养1周后,进行骨质疏松造模手术——双侧卵巢切除术(OVX),4周后,进行牙周炎造模手术——分别于双侧上颌骨第一、第二磨牙进行8字结扎绑线术(LIG),4周后拆除绑线,用药组开始辛伐他汀给药。8周后处死所有大鼠,收集双侧上颌骨和血清,分别进行进一步检测。检测包括micro-CT扫描,硬组织切片观察、染色,酶联免疫吸附实验(ELISA)。结果相比于对照OVX+LIG组,OVX+LIG+Local SIM组可见明显釉牙骨质界-牙槽嵴顶(CEJ-ABC)距离的减少(P<0.05),OVX+LIG+Oral SIM组与OVX+LIG+Local SIM组可见明显牙槽骨的骨密度(BMD)和骨体积分数(BVF)升高,OVX+LIG+Oral SIM组可见明显骨钙素(OC)上升,抗酒石酸酸性磷酸酶5b(TRAP5b)下降。结论局部或全身系统应用辛伐他汀能减缓牙周炎伴骨质疏松大鼠上颌骨的骨丢失,其中局部注射辛伐他汀对牙槽嵴顶骨形成具有促进作用。     

Effects of Estrogen Deficiency and/or Caffeine Intake on Alveolar Bone Loss,Density, and Healing: A Study in Rats

Background: The aim of this study is to evaluate the effects of caffeine and/or estrogen deficiency on ligature‐induced bone loss (BL), trabecular bone area (TBA), and postextraction bone healing (BH). Methods: Rats were assigned into one of the following groups (15 each): 1) control = non‐ingestion of caffeine/sham surgery; 2) caffeine = ingestion of caffeine/sham surgery); 3) ovariectomized (OVX) = non‐ingestion of caffeine/ovariectomy; or 4) caffeine/OVX = ingestion of caffeine/ovariectomy. The rats were under caffeine administration for 65 days and/or estrogen deficiency for 51 days. On day 21 after ovariectomy, one first mandibular molar received a ligature and the contralateral tooth was not ligated. The first maxillary molars were extracted 8 days before sacrifice. BL, TBA, the positive cells for tartrate‐resistant acid phosphatase (TRAP), receptor activator of nuclear factor‐κB ligand (RANKL), and osteoprotegerin (OPG) were analyzed in the furcation area of mandibular molars. Histometric BH and gene expression of bone morphogenetic protein (BMP)‐2, BMP‐7, osteopontin, and bone sialoprotein were evaluated in alveolar sockets. Results: The caffeine group presented the greatest BL and the OVX group the highest number of TRAP‐positive (TRAP⁺) cells around ligated teeth (P <0.05). The control group presented higher TBA and BH than the other groups (P <0.05). All test groups presented higher RANKL/OPG⁺ cells than the control group around ligated/unligated teeth. The OVX and caffeine/OVX groups presented a greater number of TRAP⁺ cells around unligated teeth than the control group (P <0.05). There were no differences among groups for gene expression (P >0.05). Conclusions: Caffeine increased BL in ligated teeth. Caffeine and/or estrogen deficiency decreased TBA in the unligated teeth and reduced BH after tooth extraction.     

Effects of ovariectomy on turnover of alveolar bone in the healed extraction socket in rat edentulous mandible

Objective

The number of patients with postmenopausal osteoporosis receiving dental implants because of edentulism is increasing. Since osseointegration around implants requires formation and maintenance of new bone, knowledge of how ovariectomy (OVX) affects turnover of mandibular and maxillary bone is required. In the present study, we investigated the effects of OVX on turnover of alveolar bone in the healed extraction socket of the rat left mandibular incisor.

Methods

The molars and the incisor on left side in 6-month-old Sprague–Dawley female rats (n = 38) were extracted and left to heal for 4 months. Animals were then ovariectomized and killed at the time of OVX (baseline) (n = 4), 6 weeks (n = 10), 6 months (n = 12) and 9 months (n = 12) post-OVX. Changes in bone mass and bone turnover were assessed using static and dynamic histomorphometric parameters.

Results

Bone turnover was increased by ovariectomy (OVX) as reflected by increased static parameters of bone formation and resorption. The changes in dynamic parameters were not statistically significant. Cancellous bone volume/total volume (%) in the post-OVX group decreased more than that in the control group.

Conclusions

Our results suggest that OVX increases the turnover of alveolar bone in the healed extraction socket of rat mandibular incisor, resulting in a decrease of cancellous bone volume with time.     

成骨特异转录因子 Runx2 在去势大鼠正畸牙移动牙周组织中的表达

目的：研究成骨特异转录因子Runx2在去势大鼠正畸牙移动过程中牙周组织内的表达规律。方法：选用3月龄雌性未孕SD大鼠50只,随机分为去势组（OVX）与假手术组（Sham）各25只。全麻下行大鼠去势术或假手术,术后饲养3个月。构建大鼠上颌第一磨牙正畸牙移动模型,并分别于牙移动0d、1d、3d、7d与15d处死去势组大鼠和假手术组大鼠各5只,取上颌第一磨牙周围牙周组织,行H-E染色和免疫组织化学染色后观察正畸牙移动牙周组织的改建。结果：去势大鼠与假手术大鼠正畸牙移动过程中牙周组织的改建基本相似,即张力区以成骨为主,压力区以破骨为主。去势组大鼠牙移动15d张力区成骨细胞及压力区破骨细胞均显著多于假手术组大鼠（尸〈0．05）。大鼠正畸牙移动过程中牙周组织Runx2表达先升后降。牙移动1d、3d、7d张力区与压力区Runx2表达均显著高于0d（P〈0．05）,15d与0d则无显著差异。去势组大鼠牙移动牙周组织Runx2表达变化与假手术组大鼠基本一致,但是去势组1d压力区和7d张力区Runx2表达均显著高于假手术组大鼠（P〈0．05）。结论：去势大鼠正畸牙移动过程中的牙周组织改建符合正畸牙移动的基本规律,但其牙周组织的改建更为活跃。去势大鼠正畸牙移动牙周组织内Runx2的表达增强,这可能与活跃的牙周组织改建相关,其机制需进一步研究。     

雌孕激素缓释凝胶对去势牙周炎大鼠牙槽骨吸收部位修复再生作用的研究

目的:研究雌孕激素缓释凝胶对去势牙周炎大鼠牙槽骨修复再生的作用。方法:选取6月龄雌性大鼠,随机分为去势组和假手术组,去势术后12周检测血清钙、磷、碱性磷酸酶和E2浓度。用0.2 mm结扎线于单侧第一磨牙牙颈部结扎,结扎4周后,建立大鼠牙周炎模型,用Micro-CT观察骨丧失情况。移除结扎线,将大鼠分为假手术生理盐水组,假手术上药组,去势生理盐水组和去势上药组。将配制好的雌孕激素缓释凝胶和生理盐水分别注入大鼠牙周袋内,治疗8周后,进行Micro-CT分析和HE组织学染色。结果:去势大鼠骨密度降低,血清钙、磷浓度降低,碱性磷酸酶活性升高,E2浓度降低。牙周结扎后,假手术组牙槽骨有水平吸收,去势组牙槽骨不仅水平方向上的吸收,垂直方向上也同样有吸收,牙槽嵴高度降低明显,根分叉暴露。雌孕激素缓释凝胶联合应用后,牙槽骨骨密度(BMD)升高、骨小梁数量(Tb.n)增加、骨小梁分离度(Tb.Th)增加、骨小梁连接数(Tb.Pf)增多,破骨细胞减少,新骨形成。结论:雌孕激素缓释凝胶能够促进去势大鼠牙槽骨吸收部位的修复再生。     

The effect of oestrogen deficiency on the alveolar bone resorption caused by traumatic occlusion

This study, using 132 female rats, was designed to investigate whether oestrogen loss facilitates alveolar bone alterations induced by traumatic occlusion. Rats were ovariectomized (OVX) or underwent sham-operation (Sham). Seven days after surgery, half of the rats in each group were subjected to experimental traumatic occlusion (trauma), and the other half were left untreated. Thus, there were four groups: OVX+trauma, Sham+trauma, OVX, and Sham. Rats in each group were killed 1, 3, 5, 7, or 10 days after the introduction of occlusal trauma. The resected mandibles were processed without decalcification, and histomorphometric measurements were performed in the alveolar bone adjacent to the periodontal ligament of the first molar. The statistical assessment of the time- and group-specific differences by analysis of variance revealed significant differences between the OVX+trauma and Sham+trauma groups in the resorption parameters, but not in the formation parameters. The results show that the alveolar bone dynamics induced by traumatic occlusion are enhanced by oestrogen deficiency.     

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.