天然羟基磷灰石／壳聚糖复合材料修复种植体周围骨缺损的实验研究

目的：探讨天然羟基磷灰石／壳聚糖复合材料修复种植体周围骨缺损的可行性。方法：预成直径为2．0mm的螺纹纯钛种植体48颗,新西兰白兔12只,每只在双侧胫骨各钻2孔,实验组孔径4．5mm,对照组孔径为2．0mm,实验组同期植入复合材料＋纯钛种植体,对照组只植人种植体,分别于术后4、8、12、16周随机处死三只动物,制作硬组织标本、扫描电镜和能谱分析标本,观察移植材料及种植体一新骨界面变化情况,并分析每一时期两组Ca、P、S元素的含量。结果：实验组复合材料植入后未见明显的异物反应。实验组种植体植入后未发生明显移位,16周时能与周围骨组织形成较好的骨结合。能谱分析显示,16周时两组Ca、P、S元素差异无显著性。结论：天然羟基磷灰石／壳聚糖复合材料可以作为种植体周围骨缺损的修复材料,并能促进种植体一骨界面形成较为完善的骨结合。     

活性胶原基纳米骨修复即刻种植体周围骨缺损的研究

目的:观察胶原基纳米骨(nHAC)及活性胶原基纳米骨(AnHAC)修复即刻钛种植体周围骨缺损的效果,为临床应用奠定理论依据。方法:犬下颌骨拔牙创区制造即刻种植体周围骨缺损,分别采用植入nHAC、AnHAC、自体牙槽松质骨及不植入任何材料4种不同方法修复种植体周骨缺损,术后6周、12周,采用X线摄片、骨密度测量及组织学检查,观察新骨形成情况和新骨与种植体的关系。结果:两组实验动物中,除空白对照组外,骨缺损区均愈合良好,未见种植体周围炎发生。1)nHAC组:术后6周已有新生骨小梁形成,术后12周修复骨缺损,种植体边缘可见较多新骨形成;2)AnHAC组:成骨过程较早,术后6周即有较多新生骨组织出现,术后12周新骨组织与宿主骨完全融合,并与种植体表面形成广泛的骨性结合。结论:nHAC具有良好的骨引导作用,可良好地修复种植体周骨缺损,复合rhBMP-2后效果更佳。临床上可根据具体情况选用修复即刻种植体周围骨缺损的方法。     

Gel-HA-M/PRP复合材料对种植体周围骨缺损修复的实验研究

目的:观察明胶-羟基磷灰石-米诺环素(Gel-HA-M)纳米复合物与富血小板血浆(platelet-rich plasma,PRP)复合(GEL-HA-M/PRP)修复种植体周围骨缺损的效果,探讨其作为种植体周围骨缺损修复材料的可行性.方法:普通健康杂种犬6只,拔除双侧下颌第二、三、四前磨牙,3个月后每侧拔牙处植入3枚...     

富血小板血浆复合珊瑚羟基磷灰石在即刻种植术中的应用

目的:探讨富血小板血浆复合珊瑚羟基磷灰石,修复即刻种植时种植体周围骨缺损的效果。方法:8只实验用犬,拔除双侧下颌第2、3、4前磨牙,每个拔牙窝即刻植入1枚种植体,并制备种植体颈部的半环状骨缺损。将同一实验犬的6处种植体周骨缺损随机分为3组给予不同方法处理,每组2处。具体如下:A组骨缺损中植入珊瑚羟基磷灰石-富血小板血浆复合物,B组骨缺损中单纯植入珊瑚羟基磷灰石,C组中骨缺损空置。术后3个月处死动物,制作标本,分别进行大体观察,生物力学测试,组织形态学观察、测试(骨结合率)。结果:骨结合率、生物力学结果一致,均为A组最佳,B组次之,C组最差,且3组间差异有统计学意义(P<0.05)。结论:富血小板血浆复合珊瑚羟基磷灰石可促进即刻种植时种植体周围的骨生成,提高骨结合率。     

BMSC-HA/TCP修复羟基磷灰石种植体周围骨缺损的实验研究

目的:探讨应用小型猪BMSC为种子细胞,HA-TCP为支架修复种植体周围骨缺损的可行性。方法:将8只小型猪,随机分为实验组及对照组。在两组种植体周围骨缺损区分别植入细胞-支架材料,单纯支架材料,于种植体植入后1个月,3个月取材,进行观察。结果:细胞-支架组1个月骨缺损区可见新生编织骨包绕支架材料,3个月可见支架材料降解,密质骨形成。支架组1个月骨缺损区纤维组织包裹支架材料,3个月支架材料部分降解。结论:细胞-支架构建方式可作为修复羟基磷灰石种植体周围骨缺损的方法之一。     

应用羟基磷灰石生物陶瓷引导骨再生对单牙种植修复体周围牙龈的影响

目的:探讨伴有不同程度骨缺损的单牙缺失区引导的再生骨对种植修复体周围牙龈形态美学的影响.材料与方法:对53例单牙缺失伴有不同程度牙槽骨缺损的病人进行标准牙种植手术,同期应用羟基磷灰石生物陶瓷行骨引导再生术,观察骨愈合和引导再生骨的形成情况.在修复即刻、修复后半年和1年时,对种植体顶骨缘吸收和种植修复体周围牙龈形态、龈缘水平、牙龈质地、龈乳头结构和龈缘出血状况的变化进行评价.结果:引导的再生骨充满骨缺损,骨质良好.在修复后1年,4例出现种植体顶边缘骨吸收超过1个螺纹,与骨缺损类型无关.随功能负重时间延长,种植修复体牙龈美学效果改善明显,但牙龈形态和龈乳头结构不完整在骨缺损较大病例中的发生率明显高于小型骨缺损病例.结论:羟基磷灰石生物陶瓷充具有良好的引导骨再生作用,充足的引导再生骨是维持种植修复体周围牙龈正常形态结构的决定性因素.     

纳米羟基磷灰石修复兔颌骨缺损的组织学研究

目的研究纳米羟基磷灰石修复颌骨缺损的生长特性及生物相容性。方法24只健康新西兰大白兔随机分为实验组及对照组。在下颌骨体部造成直径1.0cm的骨缺损,实验组以纳米羟基磷灰石修复,对照组以普通羟基磷灰石修复,于术后1周、4周、8周、12周分别处死,用医学图像分析系统分析各组分的组织生成量,进行组织学定性和定量分析,并进行统计学处理。结果纳米羟基磷灰石组骨缺损修复区随时间增长修复材料被利用与新生组织结合成骨而不断减少,直至与正常骨接近而趋于稳定;HA组新生骨仅围绕材料生成。结论纳米羟基磷灰石可与新生骨组织结合且成骨较快,有良好的生物相容性。     

骨移植与骨引导再生技术联合应用修复种植体周围骨缺损的实验研究

目的:评价不同的骨移植材料结合钛膜和胶原膜修复种植体周围骨缺损效果,为临床决策提供实验依据.材料与方法:8条健康成年杂种犬拔除双侧下颌前磨牙3个月后,每侧缺牙区植入4枚钛钉,并于钛钉颊侧制造骨缺损,分别植入自体骨、Bio一oss、1:2的自体骨和Bio-oss混合物、2:1的自体骨和Bio-oss混合物.两侧分别覆盖钛膜和胶原膜.5个月后取材,通过影像学、组织学和免疫组化学技术观察骨缺损区生成新骨的质量和成骨活性.结果:种植钉无松动脱落.2例钛膜暴露但无脱落,无胶原膜暴露.钛膜下的钛钉顶部被新生骨覆盖,在胶原膜覆盖的钛钉颊侧骨面凹陷,钛膜侧新骨高度大于胶原膜组.X线片可见钛钉与骨结合紧密,钛膜侧植骨区饱满,密度较高.硬组织磨片显示种植钉与植骨材料形成了良好的骨整合,胶原膜组的骨-种植体接触率(BIC)和种植体周围骨面积(BA)均略高于钛膜组,但两者无统计学差异.2:1自体骨和Bio-oss的混合物的BIC和BA均高于1:2比例组,有统计学差异.2:1比例组与1:2比例组植骨材料相比,骨缺损处新生骨成熟度高.饱和苦味酸-天狼猩红-偏振光法和免疫组织化学SABC法观察I型胶原和骨钙素,各组未见存在显著差异.结论:自体骨、Bio-oss及自体骨和Bio-oss不同比例的混合物,在修复种植体周围3mm骨缺损时,均可获得满意效果,但自体骨比例大者骨整合程度更好.钛膜下新骨生成量大于胶原膜,但质地和活性无明显区别.讨论:修复种植体周围小的骨缺损(＜3mm)时,选用哪种骨移植材料都可以.钛膜虽然容易暴露,但它的帐篷作用好,其下成骨量大,价格便宜,适于国内推广使用.     

纳米羟基磷灰石/聚酰胺66复合人工骨修复颅骨缺损的动物实验研究

目的研究纳米羟基磷灰石/聚酰胺66复合生物活性人工骨作为骨缺损修复材料的可行性。方法将人工骨材料的预制件植入人工形成的兔颅骨临界缺损区域内,通过大体标本观察、X线及锝(99mTc)亚甲基二磷酸盐核素骨显像检查评价该材料的骨缺损修复能力,并动态评价修复后受植区内的骨代谢变化。结果纳米羟基磷灰石/聚酰胺生物活性人工骨具有良好的生物相容性,对颅骨及其颅内代谢无影响,可在兔颅骨临界缺损区域内引导骨再生。结论纳米羟基磷灰石/聚酰胺生物活性人工骨材料具备骨缺损修复材料所需的良好生物学特性。     

应用羟基磷灰石生物陶瓷引导骨再生对单牙种植修复体牙龈形态的影响

目的 探讨伴有不同程度骨缺损的单牙缺失区引导的再生骨对种植修复体周围牙龈形态美学的影响.方法 对53例单牙缺失伴有不同程度牙槽骨缺损的患者进行标准牙种植手术,同期应用羟基磷灰石生物陶瓷行骨引导再生术(GBR),观察引导再生骨的形成情况.在修复即刻、修复后3、6个月时,对种植体顶骨缘吸收和种植修复体周围牙龈形态、龈缘水平、牙龈质地、龈乳头结构和龈缘出血状况的变化进行评价.结果 引导的再生骨充满骨缺损,骨质良好.在修复后6个月,4例出现种植体顶边缘骨吸收超过1个螺纹,与骨缺损类型无关.随功能负重时间延长,种植修复体牙龈美学效果改善明显,但牙龈形态和龈乳头结构不完整在骨缺损较大病例中的发生率明显高于小型骨缺损病例.结论 羟基磷灰石生物陶瓷具有良好的引导骨再生作用,充足的引导再生骨是维持种植修复体周围牙龈正常形态结构的决定性因素.     

复合牛骨形成蛋白多孔中空种植体成骨效应的研究

目的　利用激光扫描共聚焦显微镜(LSCM)观察牛骨形成蛋白复合种植体成骨效应。方法　将天然提取的牛骨形成蛋白(bBMP)与多孔中空钛种植体相复合形成人工复合种植体,植入狗下颌骨,并设同等规格的实心柱状钛种植体及不复合bBMP的多孔中空柱状钛种植体植入狗下颌骨为对照组。应用三色荧光标记LSCM观察复合种植体周围骨整合情况。结果　实验组复合种植体在各时期成骨能力和成骨量均明显优于对照组。结论　复合种植体可诱导早期、大量、较持久的成骨;LSCM对种植体周围成骨行为进行观察是一种准确、有效的手段。     

纯钛种植体与非血管化髂骨骨结合的组织学观察

目的：研究纯钛种植体和非血管化髂骨块的骨结合情况。方法：10只杂种犬被随机分成5组，分别切取两侧游离髂骨移植于对侧，移植骨内同时植入钛种植体，术后不同时间点取材，组织学观察。结果：3周时，移植骨以吸收和坏死为主，6周时有新骨形成，9周时新骨形成的数量增加，12周时移植的骨块成活，骨组织改建完成，植入的钛种植体和移植的髂骨块之间无软组织介入，标志种植体与移植骨之间骨结合完成。结论：在本实验条件下，钛种植体和非血管化髂骨块可以形成完全骨结合。     

显微CT与硬组织切片技术在评价牙种植体骨结合中应用的对比研究

目的 :探讨最佳反映牙种植体表面骨结合情况的检测方法。方法 :4只beagle犬下颌骨延期植入40枚种植体,在2周和4周时取样进行显微CT检测和硬组织切片制作,对比两种检测方法的效果和特点。结果:显微CT具有连续性和完整性的优势,可以宏观地观察到种植体周围骨质情况,但是由于金属伪影的存在,它对种植体-骨界面成骨现象显示不够清晰。硬组织切片是一种单层组织切片,制作过程较复杂,但其对种植体-骨界面的细微情况显示较清晰。结论:显微CT更适用于对种植体周围总体成骨的评估,而种植体表面成骨的细微变化宜采用硬组织切片。     

Osseointegration and foreign body reaction: Titanium implants activate the immune system and suppress bone resorption during the first 4 weeks after implantation

Background

Osseointegration mechanisms are still not entirely understood.

Purpose

The present pilot study aims at demonstrating the involvement of the immune system in the process of osseointegration around titanium implants, comparing bone healing in the presence and absence of a titanium implant.

Materials and Methods

Fifteen New Zealand White rabbits had one osteotomy performed at each of the distal femurs; on one side, no implant was placed (sham) and on the other side a titanium implant was introduced. Subjects were sacrificed at 10 and 28 days for gene expression analysis (three subjects each time point) and for decalcified qualitative histology (six subjects each time point). At 10 days, the three subjects for gene expression analysis were part of the six subjects for histology.

Results

Gene expression analysis: at 10 days, ARG1 was significantly up‐regulated around titanium, indicating an activation of M2‐macrophages. At 28 days CD11b, ARG1, NCF‐1, and C5aR1 were significantly up‐regulated, indicating activation of the innate immune system, respectively M1‐macrophages, M2‐macrophages and group 2‐innate lymphoid cells, neutrophils, and the complement system; on the other hand, the bone resorption markers RANKL, OPG, cathepsin K, and TRAP were significantly down‐regulated around titanium. Histology: at 10 days new bone formation is seen around both sham and titanium sites, separating bone marrow from the osteotomy/implant site; at 28 days no bone trabeculae is seen on the sham site, which is healing at the original cortical level, whereas around titanium implants, bone continues into organization of more mature cortical‐like bone, forming a layer between the implant and the bone marrow.

Conclusions

The presence of a titanium implant during bone healing activates the immune system and displays type 2 inflammation, which is likely to guide the host‐biomaterial relationship. At the same time, bone resorption is suppressed around titanium sites compared to sham sites after 4 weeks of implantation, suggesting a shift to a more pronounced bone forming environment. This suggests two important steps in osseointegration: identification of the titanium foreign body by the immune system and the development of a bone forming environment, that at tissue level translates into bone build‐up on the titanium surface and can be perceived as an attempt to isolate the foreign body from the bone marrow space.     

非血管化髂骨和下颌骨与钛种植体结合的比较研究

目的 :研究非血管化髂骨和下颌骨与钛种植体结合的组织学特点。方法 :12只杂种犬随机分为 6组。切取 15mm× 5mm的下颌骨骨质 ,将骨块移植于对侧下颌骨人工骨缺损区 ,然后切取同样大小的髂骨骨块 ,移植于下颌骨骨缺损区 ,同时植入 2枚钛种植体 ,用种植体固定骨块。术后不同时间点取材 ,组织学观察。结果 :髂骨移植后早期以溶解坏死为主 ,6周时开始重建 ,种植体为混合界面 ;12周时改建基本完成 ,种植体形成骨结合。而下颌骨移植后早期移植骨吸收不明显 ,只是哈佛氏管扩大 ,与种植体界面间未见新骨形成 ;12周时移植骨内出现新生骨 ,骨吸收停止 ,种植体为混合界面 ,界面有不成熟的新生骨沉积 ,新骨与原骨结合不紧。 18周 ,种植体形成骨结合。 2 4周 ,移植的髂骨和下颌骨与骨床均融为一体 ,下颌骨与髂骨相比整体致密。结论 :髂骨与下颌骨移植后的修复过程及它们与钛种植体的骨结合过程不同 ,但均能形成骨性结合。下颌骨与种植体形成骨结合的时间比髂骨长     

转化生长因子-β1基因治疗对种植体周骨质疏松的影响

目的探讨转化生长因子- β1（TGF- β1）基因治疗对种植体周围骨质疏松和骨缺损的影响。方法构建pCDNA3.1（+）- TGF- β1真核表达载体，转染大鼠骨髓间充质干细胞（BMSCs），并与聚乳酸- 羟基乙酸（PLGA）体外黏附。制备骨质疏松大鼠股骨植入钛种植体模型，将24只Wister大鼠随机分为实验组、对照组和空白对照组，实验组为在种植体周骨缺损处植入TGF- β1基因修饰BMSCs复合PLGA；对照组为BMSCs复合PLGA。术后第4和8周取标本行免疫组化和组织学分析，观察种植体周骨组织中TGF- β1的表达和组织学变化。结果术后第4周，实验组骨缺损区的TGF- β1表达较对照组和空白对照组明显；第8周实验组骨缺损区被新生骨充填，骨质较对照组和空白对照组明显改善。结论TGF- β1基因修饰BMSCs体内回植后，可在种植体周围骨组织内表达TGF- β1，并可以影响种植体周骨缺损的修复和骨质疏松状况。     

Effects of Simvastatin on bone healing around titanium implants in osteoporotic rats

Objectives: Osteoporosis is known to impair the process of implant osseointegration. The recent discovery that statins (HMG‐CoA reductase inhibitors) act as bone anabolic agents suggests that statins can be used as potential agents in the treatment of osteoporosis. Therefore, we hypothesized that statins will promote osteogenesis around titanium implants in subjects with osteoporosis. Material and methods: Fifty‐four female Sprague Dawley rats, aged 3 months old, were randomly divided into three groups: Sham‐operated group (SHAM; n=18), ovariectomized group (OVX; n=18), and ovariectomized with Simvastatin treatment group (OVX+SIM; n=18). Fifty‐six days after being ovariectomized (OVX), screw‐shaped titanium implants were inserted into the tibiae. Simvastatin was administered orally at 5 mg/kg each day after the placement of the implant in the OVX+SIM group. The animals were sacrificed at either 28 or 84 days after implantation and the undecalcified tissue sections were obtained. Bone‐to‐implant contact (BIC) and bone area (BA) within the limits of implant threads were measured around the cortical (zone A) and cancellous (zone B) bone regions. Furthermore, bone density (BD) of zone B in a 500 μm wide zone lateral to the implants was also measured. Results: There were no significant differences in BIC and BA measurements in zone A in any of the three groups at either 28 or 84 days after implantation (P>0.05). By contrast, in zone B, significant differences in the measurement of BIC, BA, and BD were observed at 28 and 84 days between all three groups. Bone healing decreased with lower BIC, BA, and BD around implant in OVX group compared with other two groups, and Simvastatin reversed the negative effect of OVX on bone healing around implants with the improvement of BIC, BA, and BD in zone B. Conclusion: Osteoporosis can significantly influence bone healing in the cancellous bone around titanium implants and Simvastatin was shown to significantly improve the osseointegration of pure titanium implants in osteoporotic rats.     

Thyroid hormones may influence cortical bone healing around titanium implants: a histometric study in rats

BACKGROUND: The aim of the present study was to evaluate, by histometric analysis, the influence of the thyroid hormones, triiodothyronine (T(3)) and thyroxine (T(4)), on bone healing around titanium implants inserted in rat tibiae. METHODS: Forty-two male Wistar rats were randomly assigned to the experimental groups: G1 = healthy animals (control; N = 15); G2 = hypothyroidism (N = 13); and G3 = hyperthyroidism (N = 14). Once alterations were confirmed by total serum levels of T(3) and T(4), one screw-shaped titanium implant was placed in the rat tibiae. Sixty days later, the animals were sacrificed, and undecalcified sections were obtained. Bone-to-implant contact (BIC), bone area within the limits of the implant threads, and bone density in a 500-microm-wide zone lateral to the implant were obtained separately for the cortical (zone A) and cancellous (zone B) bone regions. RESULTS: Intergroup analysis demonstrated that thyroid hormones may significantly affect cortical bone healing around titanium implants. Hyperthyroidism significantly increased the area of newly formed bone in zone A (P <0.05), whereas hypothyroidism significantly decreased the area of newly formed bone and bone density around the implant in zone A (P <0.05) compared to the healthy group. In addition, hyperthyroidism significantly increased BIC extension in zone A compared to hypothyroidism (P <0.05). CONCLUSION: Thyroid hormones may influence the healing process in the cortical bone around titanium implants placed in rats, whereas cancellous bone seems to be less sensitive to changes in T(3) and T(4) serum levels.     

A histomorphometric and biomechanical study of the effect of delayed titanium implant placement in irradiated rabbit bone

Background: The time interval from irradiation to implant surgery has been considered an impact factor for implant integration in irradiated bone and the importance of a long interval between the radiation trauma and reconstructive bone surgery has been suggested. Purpose: The present study was undertaken to histomorphometrically and biomechanically analyze the effect of delayed implant placement on bone healing around titanium implants in irradiated bone. Materials and Methods: Rabbits were given a single dose of 15 Gy Cobalt⁶⁰ radiation to one hind leg, the other hind leg serving as a control. Titanium screws were inserted into the femur and tibia directly and at 12 weeks and 52 weeks after irradiation. The implants were evaluated after a healing time of 8 weeks. The torques necessary for removal of the implants were measured. Histomorphometry with respect to bone‐metal contact and amount of bone surrounding the implants was performed. Results: The biomechanical force necessary to unscrew the titanium implants in the irradiated bone was significantly increased after a resting period of 1 year between irradiation and implant placement, compared to direct implant placement. The histornorphometric evaluation showed an improvement of bone healing around the implants in the irradiated bone, both after a resting period of 12 weeks and after 1 year compared to direct implant placement. Conclusions: It is concluded that a relatively long interval between irradiation and reconstructive bone surgery will improve osseointegration of titanium implants in irradiated rabbit bone.