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。     

Assessment of aging characteristics of female condylar trabecular structure by cone-beam computed tomography

Objectives

This study was performed to analyze the aging-related changes of the female condylar bone mineral density (BMD) and trabecular structure by cone-beam computed tomography (CBCT), and determine whether the condylar structure shows obvious changes after menopause.

Methods

The CBCT images of 160 female patients who met the inclusion criteria for the study were collected and divided into four groups by age (20–29 years, 30–39 years, premenopausal, and postmenopausal groups). Computer processing software CT-Analyser (Version 1.15.2.2+; SkyScan, Antwerp, Belgium) was used to measure the condylar BMD and related indexes, namely the bone volume/tissue volume ratio (BV/TV), trabecular number (Tb.N), trabecular thickness (Tb.Th), trabecular separation (Tb.Sp), trabecular structure model index (SMI), and bone surface area/volume ratio (BS/BV). SPSS 12.0 (SPSS Inc., Chicago, IL, USA) was used to analyze the radiographic findings and statistical differences.

Results

No significant differences were found between the bilateral condyles in each group (P?>?0.05). BV/TV, Tb.N, and Tb.Th of the condyle decreased with age, and the postmenopausal group showed significantly different values for each index compared with the other groups (P?<?0.01). Tb.Sp, SMI, and BS/BV of the condyle increased with age, and the postmenopausal group showed significantly different values for each index compared with the other groups (P?<?0.01).

Conclusions

With increasing age, the female condylar bone volume decreases, the Tb.N and Tb.Th decrease, the gap between the trabecular bone increases, and plate-like trabecular bone gradually transforms into a rod-like form. These changes are much more obvious in postmenopausal women.

     

Volumetric analysis of the periodontal microstructure under antiresorptive therapy: an experimental study in rabbits

Objectives

The objective of this study was to volumetrically assess changes in the periodontal microstructure under antiresorptive therapy.

Materials and methods

Microtomographic scans from a total of 9 Dutch Belted rabbits having been randomly allocated to either the intravenous administration of amino-bisphosphonate (zoledronic acid) (Za) (n?=?5) or a negative control group (nZa) (n?=?4) were obtained at 10 months following a repeated drug administration. A quantification of the periodontal space thickness (P.Th) of both maxillary and mandibular most posterior premolars, as well as of the 2nd molars was performed. Bone micromorphometry was assessed by means of bone volume per total volume (BV/TV), the bone mineral density (BMD), trabecular thickness (Tb.Th), trabecular number (Tb.N), bone surface (BS), and the specific bone surface (BS/BV).

Results

Za was associated with significantly higher P.Th (P?=?0.010), which was most pronounced in the upper jaw. Bone micromorphometry revealed no significant differences among the two groups, i.e., Za and nZa, for all the investigated parameters.

Conclusions

Volumetric analysis revealed that antiresorptive therapy was associated with periodontal space widening, whereas major effects on the bone micro-morphology could not be observed.

Clinical relevance

A deep understanding of specific periodontal and alveolar bone alterations in patients under antiresorptive therapy might help to prevent the onset of medication-related osteonecrosis of the jaw.

     

不同方式处理犬下颌磨牙区即刻种植间隙的效果评价

目的: 探讨在犬下颌磨牙区即刻种植中,不同方式处理拔牙窝与种植体之间的间隙后的新骨形成情况。方法: 选择 6 条 1.5~2.0 岁的拉布拉多犬作为实验对象,在每条犬下颌骨中拔除两侧的第四前磨牙和第一磨牙,分别植入 4 颗牙种植体（Astra Tech^®,4.0 mm × 10 mm）。种植体和拔牙窝骨壁之间的近远中间隙分别进行3种处理,分为空白组（NN组）、胶质银明胶海绵（Gelatamp） 组（EN组）和 Gelatamp + 可吸收胶原膜（CM）组（EG 组）。术后12周收集标本,进行显微CT 扫描和组织学分析。采用SPSS 25.0软件包进行统计学分析。结果: 牙种植术后 12 周存活率为 100%。显微CT 扫描结果显示,新骨高度、骨矿物质密度（BMD）、骨体积分数 （BV/TV）、骨表面积骨体积比（BS/TV）、骨小梁厚度（Tb.Th）、骨小梁数（Tb.N）和骨小梁间距（Tb.Sp）等指标,组间无显著差异。组织学分析结果显示,新骨形成面积和种植体与骨接触面积（BIC）在组间无统计学差异。结论: 使用不同方式处理种植体与拔牙窝之间的间隙后的12周内,与空白对照组相比,单独放置 Gelatamp 或与 CM 联合使用,对种植体周围新骨形成、BIC、BMD、BV/TV、BS/TV、Tb.Th、Tb.N 及 Tb.Sp 等均无显著影响。     

Microcomputed tomographic analysis of bone microarchitecture after sinus augmentation with hyaluronic matrix: a case–control study

Background

The aim of this study was to analyze trabecular microarchitecture of augmented sinuses with hyaluronic matrix and xenograft by microcomputed tomography, and to investigate whether hyaluronic matrix has an effect on the newly formed bone quality.

Materials and methods

Thirteen patients undergoing maxillary sinus augmentation were included in this split-mouth study. Right and left sinus sites were randomly assigned to test and control group. In test group, the sinus was grafted with hyaluronic matrix and xenograft; in control group, only with xenograft. Four months after augmentation, bone samples were harvested during implant placement and analyzed for the following trabecular microarchitecture parameters using microcomputed tomography: bone volume (BV), total volume (TV), bone volume fraction (BV/TV), bone surface (BS), specific bone surface (BS/BV), bone surface density (BS/TV), trabecular thickness (Tb.Th), trabecular separation (Tb.Sp), trabecular pattern factor (Tb.Pf), and fractal dimension (FD).

Results

There was statistically significant difference only for BS/TV parameter between two groups. BS/TV was higher in hyaluronic matrix group compared with control group.

Conclusions

Addition of hyaluronic matrix to xenograft may enhance bone quality in terms of bone surface density. However, more research investigating the microstructural variation of augmented sinuses is needed with a greater sample.

     

感觉神经肽与P物质缓释微球对小鼠拔牙窝成骨的作用

目的:验证负载感觉神经肽与P物质(substance P,SP)明胶缓释微球能否促进拔牙窝牙槽骨生成。方法:乳化交联法制备直径10~100μm的明胶微球,将10-6 mol/L的SP、神经肽降钙素基因相关肽(calcitonin gene-related peptide,CGRP)与微球混合制成载药缓释系统。27只成年KM小鼠随机分为SP组、CGRP组、SP/CGRP混合组,每组9只。分别拔除双侧上颌第一磨牙,一侧拔牙窝内放入含生理盐水的空白微球作为对照组,另一侧拔牙窝内放入载药微球作为实验组。于第4周处死小鼠,取上颌骨标本,制作硬组织切片,进行组织形态学分析,观察新骨形成情况。结果:术后4周测量新骨组织体积比例(bone volume/tissue volume,BV/TV),SP实验组为(30.25±0.92)%,同型对照组为(10.66±0.83)%,两组比较差异有统计学意义(P<0.05);CGRP实验组为(19.46±1.46)%,同型对照组为(8.78±1.03)%,两组比较差异有统计学意义(P<0.05);混合实验组为(59.45±3.07)%,同型对照组为(10.06±3.25)%,两组比较差异有统计学意义(P<0.05)。混合实验组为(59.453±3.071)%,混合空白组为(10.062±3.254)%,两组比较差异有统计学意义(P<0.05);骨小梁厚度(trabecular thickness,Tb.Th),混合空白组为(0.076±0.009)%,混合实验组为(0.132±0.043)%,两组比较差异有统计学意义(P<0.05);骨小梁数量(trabecular number,Tb.N),混合空白组为(0.841±0.212)%,混合实验组为(4.497±0.413)%,两组比较差异有统计学意义(P<0.05);骨密度(bone mineral density,BMD),混合空白组为(0.184±0.072)%,混合实验组为(0.615±0.010)%,两组比较差异有统计学意义(P<0.05)。结论:CGRP与SP均能够促进拔牙窝新骨生成,且两者对成骨具有协同促进作用。     

Preliminary Clinical Study to Evaluate the Relationship between Systemic Bone Turnover and the Microstructure of the Alveolar Bone

The objective of this study was to assess the possibility of developing a clinical minimally invasive and standardized method to evaluate the relationship between the microstructure of the jaw bone and systemic bone turnover. For this purpose, we performed standardized bone biopsy of the alveolar bone, and compared the 3D bone microstructure using micro-computed tomography (micro-CT) with bone mineral density (BMD) of the lumbar spine and biochemical markers of bone turnover. We evaluated a total of 9 samples taken from 6 patients by standardized biopsy using a trephine bur. BMD was evaluated using dual energy X-ray absorptiometry (DXA). Regarding the biochemical markers of bone turnover, serum bone-specific alkaline phosphatase (BAP) and serum osteocalcin (OC) were used as bone formation markers, and urinary cross-linked N-telopeptides of type I collagen (NTx) and urinary deoxypyridinoline (DPD) were selected as bone resorption markers. We scanned micro-CT images of these samples. Bone volume fraction (BV/TV), trabecular thickness (Tb.Th), trabecular number (Tb.N), trabecular spacing (Tb.Spac), fractal dimension, trabecular bone pattern factor (TBPf) and node-strut (Nd.Nd/TV, TSL/TV) were measured. Regarding the correlations between the parameters of bone microstructures, TB/TV, Tb.N, fractal dimension, and node-strut seemed to be positively correlated and Tb.Spac and TBPf seemed to be negatively correlated with each other, but Tb.Th seemed to have a low correlation with other parameters. OC and/or BAP showed a significantly high correlation with many structural parameters (p < 0.05%). In conclusion, some microstructural parameters may change according to the systemic bone turnover.     

Microcomputed tomography analysis of particular autogenous bone graft in sinus augmentation at 5 months: differences on bone mineral density and 3D trabecular structure

Objectives

This study investigated the effects of gender on the three-dimensional (3D) bone mineral density (BMD) and micromorphology of the trabeculae of matured autogenous bone grafts after sinus floor augmentation, and compared them to those of adjacent native bone.

Materials and methods

Ten bone biopsy samples were removed from the implant placement areas of patients who had received second-stage sinus floor augmentation, and analyzed by microcomputed tomography. BMD phantoms with two calcium hydroxyapatite densities (0.25 and 0.75 g/cm³) were used to determine the BMD of the grafted and native bone samples. The 3D structural parameters of the trabeculae, including percentage of bone volume (bone volume/tissue volume, BV/TV), trabecular thickness (Tb.Th), trabecular number, trabecular separation, trabecular pattern factor (Tb.Pf), and structure model index, were analyzed between males and females and between grafted bone and native bone.

Results

No significant gender-specific differences in BMD and 3D trabecular structure of either native or grafted bone were found (P?>?0.05). Compared to the adjacent native bone, the autogenous grafted bone exhibited lower BV/TV and Tb.Th as well as a higher Tb.Pf (P?<?0.05). Additionally, there was a weak positive correlation between the Tb.Th values of grafted and native bone (R ²?=?0.58).

Conclusions

In the maxillary sinus, autogenous grafted bone exhibited lower BV/TV, Tb.Th, and trabecular connectivity than the adjacent native bone. No significant gender-specific differences were found for either the BMD or 3D trabecular structure of grafted bone.

Clinical relevance

After bone remodeling, autogenous grafted bone revealed different 3D trabecular structure as compared to native bone.     

不同去势时间对大鼠牙槽骨微结构影响的比较研究

目的 比较不同去势时间对大鼠牙槽骨微结构的影响,探讨牙槽骨骨质疏松大鼠模型建立成功的参数。方法 24只6月龄雌性SD大鼠,随机分为4组：（1）对照组1（Sham1）;（2）去势组1（OVX1）;（3）对照组2（Sham2）;（4）去势组2（OVX2）。分别在全麻下行假手术和双侧卵巢去势术。于术后3个月和4个月处死各组大鼠,取双侧上颌骨标本,通过Micro-CT扫描、HE染色、抗酒石酸酸性磷酸酶（TRAP）染色、Van Gieson染色、荧光双标观察并分析牙槽骨微结构的变化。结果 去势3个月后OVX1组与Sham1组大鼠相比,体重增加25.09%（P<0.01）;牙槽骨骨体积分数（BV/TV）、骨小梁数目（Tb.N）、骨小梁分离度（Tb.Sp）,牙骨质界-牙槽嵴顶（CEJ-ABC）距离无改变（P>0.05）,骨小梁宽度（Tb.Th）降低了12.44%（P<0.05）,破骨细胞数量增加了40.12%（P<0.01）;骨形成沉积率（MAR）无明显改变（P>0.05）;去势4个月后OVX1组与Sham1组大鼠相比,体重进一步增加了26.25%（P<0.01）,BV/TV、Tb.Th、MAR分别降低了11.15%、17.22%和38.45%（P<0.01）,Tb.Sp和破骨细胞数量分别增加了81.89%和35.67%（P<0.01）,Tb.N和CEJ-ABC距离无变化（P>0.05）,HE和Van Gieson染色均表明OVX2组大鼠牙槽骨骨量降低,骨髓腔面积增加,骨小梁微结构破坏、变细,部分区域发生断裂。结论 6月龄雌性SD大鼠去势4个月后,牙槽骨发生明显骨质疏松,可作为合适的牙槽骨骨质疏松大鼠模型参数的理论依据。     

Microarchitecture of medication-related osteonecrosis of the jaw (MRONJ); a retrospective micro-CT and morphometric analysis

Medication-related osteonecrosis of the jaw (MRONJ) is a severe side effect of antiresorptive (AR) drugs such as bisphosphonates (BP) and denosumab (Dmab). Although several risk factors are described, the etiology of MRONJ is still not fully elucidated. Bone-strengthening is the primary aim of antiresorptive therapy; however, overly increased bone mass and microcrack accumulation are also discussed in MRONJ etiologies. The aim of this study is to evaluate the microarchitecture of jaw bones with micro?computed tomography (micro-CT) in AR-treated patients with or without MRONJ.Human jaw bone samples of AR-treated patients were separated into 11 groups by AR treatment bisphosphonate (BP), denosumab (Dmab), both (M) and control groups. Subgroups were divided according to the clinical localization as AR-exposed vital jaw bone (BP_exp, Dmab_exp, M_exp), osteonecrosis–margin of a sequestrum (BPO_mar, DmabO_mar, MO_mar) and osteonecrosis–sequestrum (BPO_seq, DmabO_seq, MO_seq). Healthy jaw bone (C_HB) and osteoporotic jaw bone (C_OP) represent control groups. Samples underwent retrospective micro-CT and morphometric analysis in representative units by bone volume fraction (BV/TV), bone surface density (BS/BV), trabecular thickness (Tr.Th.), trabecular number (Tr.N.), trabecular space (Tr.Sp.), Euler characteristic for bone connectivity, bone mineral density (BMD) and tissue mineral density (TMD).A total of 141 samples from 78 patients were analyzed. BV/TV of M_exp group (mean: 0.46 ± 0.27) was significantly higher than in the C_OP group (mean: 0.14 ± 0.05; p = 0.0053). Tr.Th. differed significantly between the BP_exp group (mean: 0.32 ± 0.15) and the M_exp group (mean: 0.57 ± 0.20; p = 0.0452) as well as between the BPO_seq group (mean: 0.25 ± 0.10) and the MO_seq group (mean: 0.39 ± 0.18; p = 0.0417). Signs of trabecular thickening and unorganized trabecular microarchitecture from AR-exposed- to sequestrum groups, were analyzed in 3D reconstructions. However, BS/BV, Tr.N., and Tr.Sp. showed no significant differences. Euler characteristic of the BPO_seq group (median: 7.46) doubled compared to that of the BP_exp group (median: 14.97; p = 0.0064). Mineralization parameters BMD and TMD were similar in all groups.Findings show evidence of enhanced bone mass and suspect microarchitecture in some AR-treated jaw bone compared to osteoporotic jaw bone. Despite increased bone mass, some MRONJ samples showed decreased trabecular connectivity by Euler characteristic compared to AR-treated jaw bone. These samples may indicate extensive ossification and ineffective bone mass with superficially higher bone mass without existing or even reduced mechanical stability, indicated by connectivity loss. This result might also suggest a high risk to microcrack accumulation. At some point, possibly some kind of over-ossification could lead to under-nourishment and microarchitectural weakness, creating instability, subsequently increasing vulnerability to MRONJ.     

The correlation of different methods for the assessment of bone quality in vivo: an observational study

Different methods for the assessment of bone quality were evaluated in this study. Sixty alveolar bone areas were investigated. Peri-apical and panoramic radiographs were obtained with an aluminium scale to assess optical density. The Lekholm and Zarb (L&Z) classification was determined through radiographic analysis and the surgeon’s tactile perception. A trephine was used to obtain a bone biopsy for assessment by micro-computed tomography (micro-CT) and histomorphometry. Primary stability of the implants was assessed using insertion torque (IT) and the implant stability quotient (ISQ). The optical density on peri-apical radiographs was correlated with IT, ISQ, and micro-CT (BV, BV/BT, Tb.Th, Tb.N, BS/BV, Tb.Pf, and SMI) (rho ≤ 0.471, P ≤ 0.028). Panoramic radiography showed a correlation only with bone surface (BS) and bone surface/volume ratio (BS/TV) (rho ≤ 0.290, P ≤ 0.031). IT showed a correlation with ISQ, histometry, and micro-CT (BV, BS/TV, Tb.Th, Tb.N, BS/BV, Tb.Pf, Tb.Sp, BV/BT) (rho ≤ 0.550, P ≤ 0.022). ISQ did not show any correlation with micro-CT. The L&Z classification showed correlations with the optical density obtained in the peri-apical radiographs, histometry, osteocyte count, IT, and micro-CT (BS/BV, Tb.Sp, Tb.Pf, BV, BS/TV, Tb.Th, Tb.N) (rho ≤ 0.344, P ≤ 0.042). The L&Z bone classification and IT are reliable methods, peri-apical radiographs and ISQ are acceptable, and panoramic radiography is not a reliable method for the assessment of bone quality.     

Chronological changes in the microstructure of bone during peri-implant healing: a microcomputed tomographic evaluation

Our objectives were to examine the titanium-bone interfaces chronologically and to clarify the process of osseointegration using microcomputed tomography (microCT). The mandibular premolars of 3 dogs were extracted and 12 weeks later 2 Straumann dental implants were installed in each quadrant. The microstructural changes at the bone-implant interface at the first, fourth, and eighth weeks after installation were evaluated by microCT and a 3-dimensional image was constructed. The microstructural measurements at the bone-implant interface, including the trabecular number (Tb.N), bone volume fraction (BV/TV), structure model index (SMI), trabecular thickness (Tb.Th), trabecular separation (Tb.Sp) and connectivity density (Conn.D), were measured. Experimental outcomes were analysed for correlations between time and microstructural variables of trabecular bone. Tb.N increased significantly during the eighth week compared with that during the first and fourth week (p = 0.001, 0.002). BV/TV increased generally with time and there were significant differences (p = 0.003) between each time group. While Tb.Sp decreased with time and changed significantly during the eighth week compared with that during the first week (p = 0.021), differences in SMI, Tb.Th and Conn.D did not differ significantly according to time of implant. The significant increase in the Tb.N and BV/TV during the eighth week after insertion of implants indicates that the formation of new bone before the eighth week is the key to osseointegration.     

The effect of bone morphometric changes on orthodontic tooth movement in an osteoporotic animal model

Objective:To elucidate the effect of bone morphometric changes on orthodontic tooth movement (OTM) in zoledronic acid–treated ovariectomized rats.Materials and Methods:Twenty-one 10-week-old female Wistar rats were divided into ovariectomy (OVX), OVX with zoledronic acid administration (OVX + ZOL), and sham operation (control) groups. Two weeks after OVX, ZOL administration was initiated. Twelve weeks after OVX, a nickel-titanium closed-coil spring of 25-g force was applied mesially to the maxillary left first molar. In vivo micro–computed tomography (CT) of the left proximal tibia was performed for bone morphometric analysis every 2 weeks after OVX. In addition, OTM was investigated using micro-CT at 0, 12, and 14 weeks after OVX.Results:There were significant differences in the bone mineral content (BMC), bone volume (BV), BMC to tissue volume ratio (BMC/TV), and BV to TV ratio of trabecular bone between the control and OVX groups and also between the OVX + ZOL and OVX groups. In the OVX + ZOL group, increased BMC and BV in the cortical bone and increased bone mineral density (BMD) in the trabecular bone were observed. Interestingly, OTM in the OVX group was almost two times more than that in the control and OVX + ZOL groups. Moreover, OTM was correlated with BMD, BMC, BV, and BMC/TV in the trabecular bone.Conclusions:OVX accelerated OTM, while ZOL suppressed it. OTM demonstrated a significant negative relationship with trabecular bone mass.     

增材制造Ti-6Al-4V钛合金种植体骨结合的动物实验研究

目的探讨增材制造Ti-6Al-4V（TC4）钛合金种植体动物体内的骨结合和成骨效果,为进一步临床应用提供实验依据。 方法选择健康雄性新西兰兔42只,以兔双侧后腿股骨髁部为种植体植入区,将实验兔先分为2周（A组）、8周（B组）2个大组,每组21只;每大组中再分为3个亚组,分别为A1组、A2组、A3组和B1组、B2组、B3组,每小组7只。A1组和B1组实验兔双侧后腿股骨髁部分别植入原始表面和表面改性TC4钛合金种植体各1枚;A2组和B2组实验兔植入原始表面TC4钛合金种植体和钛骨种植体各1枚;A3组和B3组实验兔植入表面改性TC4钛合金种植体和钛骨种植体各1枚;使2周、8周均含有3种种植体各14枚。术后2、8周观察并比较分析3种种植体的植入成功率和骨结合情况,观察指标为：骨体积分数（BV/TV）、骨小梁面积密度（BS/BV）、骨小梁厚度（Tb.Th）、骨小梁数量（Tb.N）和骨小梁间隔（Tb.Sp）。对各组不同时段种植体骨界面骨密度指标,使用SPSS 21.0软件包对数据进行双因素方差分析,验证不同表面、不同时间对种植体骨结合水平的影响,并采用Tukey′s多重比较检验分析组间统计学差异。 结果3种种植体不脱钙组织切片、骨块微CT扫描及光学显微镜观察显示,随着植入后的时间进展,3种种植体表面骨组织的量逐渐增多,分布逐渐变密。2周时,表面改性TC4钛合金种植体组的BV/TV、Tb.N显著高于原始表面和钛骨组,差异有统计学意义（P<0.05）;Tb.Th显著高于钛骨组（P<0.05）;BS/BV、Tb.Sp显著低于钛骨组,差异有统计学意义（P<0.05）。8周时,3种种植体的BV/TV、BS/BV、Tb.Th、Tb.N和Tb.Sp差异均无统计学意义（P>0.05）。 结论表面改性TC4钛合金种植体2周时即能形成更多的骨组织,骨小梁的分布更密集,骨结合能力更强,有望成为口腔种植体的优选材料。     

Assessing Bone Type of Implant Recipient Sites by Stereomicroscopic Observation of Bone Core Specimens: A Comparison With the Assessment Using Dental Radiography

Background: The aim of the study is to determine if bone quality evaluation of surgically obtained bone core specimens using a stereomicroscope is reliable for determining bone quality at implant recipient sites. Methods: Bone quality was presurgically assessed in 122 edentulous ridges obtained from 62 patients using periapical radiographs and categorized according to the Lekholm and Zarb classification. During surgery, bone specimens were trephined, and bone types were immediately classified using a stereomicroscope. Microarchitectural characteristics of bone cores were evaluated after being scanned using microcomputed tomography (micro‐CT). Results: Bone types of implant sites categorized from radiography and stereomicroscope had statistically similar distribution but poor interrater agreement. Using micro‐CT, maxillae and mandibles showed significant differences in microarchitectural characteristics of bone cores. Bone volume (BV), total volume (TV), and trabecular thickness (Tb.Th) increased, whereas bone surface density (BS/BV) and open porosity (Po.[Op]) decreased in mandibular bone cores compared with those in maxillary bone cores. Moreover, micro‐CT values of BV/TV and Po.(Op) statistically correlated with bone types assessed by stereomicroscopy, particularly in mandibles (adjusted means of BV/TV of Type 2 to 4 versus Type 1 decreasing from ?9.88%, ?15.09%, ?29.31%; those of Po.(Op) ranged from 9.77%, 15.06%, 29.52% in an upward trend). However, such correlations were not found in maxillae or when bone types were classified using periapical radiographs. Conclusions: Caution is needed when using presurgical periapical radiographs to predict bone quality at implant recipient sites. Surgically preserved bone core specimens, whenever obtainable, might offer additional information to accurately assess bone quality, particularly at mandibular implant sites.     

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目的评价钛酸钡(BaTiO3)压电陶瓷涂层对种植支抗稳定性及其周围骨改建情况的影响。方法本研究于2013年8月至2014年1月在兰州军区总医院进行。选择5只成年杂种犬,将机械处理表面支抗种植钉(对照组)植入犬左侧下颌骨,BaTiO3压电陶瓷涂层支抗种植钉(实验组)植入犬右侧下颌骨,每侧各2枚;术后2周,给予1.96 N交互牵引力持续1个月,测量2枚种植体位移并通过影像学检查、组织学染色分析、生物力学检测观察种植支抗稳定性及其与周围骨结合的效果。结果与对照组相比,实验组BaTiO3压电陶瓷涂层种植支抗移动距离明显减小,骨形成活跃,骨结合率及最大拔出力显著升高,组间差异具有统计学意义(P<0.05)。结论在种植支抗表面制备BaTiO3压电陶瓷涂层可有效增加种植支抗的稳定性。     

钛酸钡压电陶瓷涂层用于种植支抗效果研究

目的    评价钛酸钡（BaTiO3）压电陶瓷涂层对种植支抗稳定性及其周围骨改建情况的影响。方法    本研究于2013年8月至2014年1月在兰州军区总医院进行。选择5只成年杂种犬,将机械处理表面支抗种植钉（对照组）植入犬左侧下颌骨,BaTiO3压电陶瓷涂层支抗种植钉（实验组）植入犬右侧下颌骨,每侧各2枚;术后2周,给予1.96 N交互牵引力持续1个月,测量2枚种植体位移并通过影像学检查、组织学染色分析、生物力学检测观察种植支抗稳定性及其与周围骨结合的效果。结果    与对照组相比,实验组BaTiO3压电陶瓷涂层种植支抗移动距离明显减小,骨形成活跃,骨结合率及最大拔出力显著升高,组间差异具有统计学意义（P < 0.05）。结论    在种植支抗表面制备BaTiO3压电陶瓷涂层可有效增加种植支抗的稳定性。     

牙周膜对于牙槽骨吸收影响的初步研究

目的 :通过影像学和组织形态学观察,比较脱位牙的再植位点与自然愈合拔牙创的牙槽骨高度,并观察保留或刮除牙周膜对再植脱位牙的牙槽骨骨量影响。方法:选取3只成年雄性健康Beagle犬,间隔拔除其下前牙3颗,并将每只实验犬的前牙分成3组,有牙周膜再植组(T1),无牙周膜再植组(T2),拔牙创自然愈合组(T3)。4个月后处死Beagle犬,切取实验位点组织块,Micro-CT扫描分析,制作硬组织磨片,HE染色后在光学显微镜下进行组织学观察及形态学观察。结果:Micro-CT分析显示,T1组骨小梁数量(Tb.N)多于其他两组(P<0.05),差异有统计学意义,而T2和T3组差异无统计学意义;骨小梁间隙(Tb.Sp)在T1组间隙明显小于T2组,差异有统计学意义(P<0.05),T2和T3组间差异无统计学意义;骨量比(BV/TV)、骨小梁厚度(Tb.Th)等骨微参数,各组间差异无统计学意义。HE染色显示,在所有试验位点颊侧牙槽嵴发生垂直骨降低,但三组间骨量吸收值的差异无统计学意义。在距颊侧牙槽嵴顶以下1 mm位置处的颊侧骨壁的水平宽度,T2和T3组间具有统计学意义(P<0.05);而在2、3 mm两个水平位置处,各组间差异均无统计学意义。结论:牙拔除后20 min内,牙再植回拔牙窝中,相比于自然愈合,可以保留更多牙槽骨骨量,而进一步保留再植牙的牙周膜活性,更有利于颊侧新骨形成。     

“脑回形(cortex-like)”微弧氧化膜钛种植体成骨的Micro-CT分析

目的: 利用Micro-CT评价“大脑皮质”(cortex-like)形貌的二氧化钛膜层在初始稳定性和继发稳定性阶段的骨-种植体结合的能力。方法: 实验组MAO(cortex-like)为 “大脑皮质”形貌种植体,对照组SLA为具有同等规格的SLA形貌的种植体,共计36颗,通过扫描电镜(SEM)等对材料表面进行表征,随机植入18只新西兰雄性兔的股骨髁部,分别于4周和8周处死取样,所得标本行Micro-CT扫描重建,分析MAO和SLA种植体表面的骨结合状况以及的骨小梁形态学参数。结果: 类“大脑皮质”形貌氧化层由微米级沟槽和纳米级孔洞组成,沟槽相互交通,接触角(6.9±1.14)°,Micro-CT检测可见:随着骨结合时间的延长,骨体积分数(BV/TV)、骨小梁数量(Tb.N)、厚度(Tb.Th)、连接密度增加(Conn.Dn)均增加,结构模型指数(SMI)、骨小梁分离度(Tb.Sp)下降,第4周时,BV/TV,SMI组间比较差异存在统计学意义(P<0.05),第8周时,BV/TV、Tb.N、Tb.Sp、Conn.Dn值组间比较差异存在统计学意义(P<0.05),MAO高于SLA组。结论: “大脑皮质”(cortex-like)形貌的二氧化钛、具有双微层结构膜层,能促进种植体的骨结合的提升,是一种良好的种植体改性方法。