应用放射性核素骨显像观察组织工程化骨修复兔下颌骨缺损的能力

目的:应用99mTc-MDP放射性骨显像观察复合兔骨髓基质细胞的纳米羟基磷灰石/胶原(BMSCs nHAC)修复兔下颌骨缺损的能力。方法:兔下颌骨体部范围为15mm×15mm的全层骨缺损分别采取相应方法修复:A组,BMSCs nHAC修复;B组,nHAC修复;C组,空白对照组,缺损不做修复。术后4、8、12周分别通过放射性核素骨显像进行监测。结果:术后4周,A组核素浓聚程度明显高于B组、C组,差异具有统计学意义,B组核素浓聚程度亦高于C组,差异具有统计学意义;术后8周,A组核素浓聚程度明显高于B组、C组,差异具有统计学意义,B组核素浓聚程度与C组无显著差异;术后12周,3组核素浓聚程度无显著性差异。结论:BMSCs nHAC修复下颌骨缺损与单独使用nHAC相比具有较好的成骨能力和血管化程度。     

复合血管内皮细胞的组织工程骨构建

目的:探讨将血管内皮细胞(vascular endothelial cell,VEC)与成骨细胞(osteoblast,OB)复合后用于血管化组织工程骨预构的可能性。方法:6只日本大耳白兔分为两组,分别在背阔肌下植入(OB+VEC)/外消旋聚乳酸(PDLLA)、OB/PDLLA。术后4、8周处死动物,大体标本、HE染色镜下观察体内成骨与血管化情况,以及血管化与成骨之间关系。结果:OB/PDLLA、(OB+VEC)/PDLLA两组植入物表面均有大量毛细血管肌纤维长入。OB/PDLLA组植入4周后可见骨组织形成,材料周围可见有小血管长入,随时间延长成骨量及血管化程度均有所增加。OB+VEC/PDLLA组可见在支架内部有大量毛细血管形成,支架周围成骨细胞活跃,成骨能力较强,在体内成骨能力及血管化程度均高于单纯成骨细胞复合支架组。结论:复合血管内皮细胞的组织工程骨成骨能力与血管化程度均高于单纯成骨细胞构建的组织工程骨。     

骨密度测量在评估骨支架材料促成骨作用中的意义

目的:用预制型无机诱导因子复合性骨组织工程支架材料对实验山羊的下颌骨角部大型箱状缺损施行骨重建再造,应用骨密度测量来评估支架材料在组织工程构建骨修复中的价值。方法:15只雌性山羊按每组5只以4、8、12周时间点分为3组,手术制备30 mm×25 mm×10 mm大型箱状缺损,左侧置支架材料,右侧空白对照。分别于4、8、12周处死1组5只山羊,行骨密度的双能X线吸收法(DXA)和X线光密度法(XBMD)检测。结果:DXA和XBMD检测,实验侧和对照侧间差异有统计学意义(P<0.05),和正常骨组间差异无显著性(P>0.05)。结论:实验侧的骨密度系数呈递增式上升,证明本支架材料在组织工程骨构建中的骨诱导作用。对照侧的骨密度系数维持较低水平,提示自发性成骨现象欠佳,在12周前的骨缺损区尚未明显出现自我修复痕迹。骨密度测量可作为术后动态监测组织工程化骨构建存活与否的指标之一。     

利用核医学方法监测自体移植骨在个体化钛支架内的转归

目的:探讨应用核医学方法监测钛支架内部移植骨的转归情况.方法:以10 只杂种犬作为实验动物.通过螺旋CT采集犬头颅CT图像,建立CAD模型,在模型上制造一侧下颌骨4 cm长的节段性缺损,并利用镜像对称重构缺损区域,设计完全匹配的个体化的植入支架,通过快速成型技术获得树脂模型,再铸造得到钛植入支架.然后手术制造下颌骨缺损,植入钛支架,并在支架内充填碎髂松质骨.术后2、4、8、12、24 周进行核素骨显像检查,连续观察移植骨的核素分布情况,判断植骨是否成活.结果:术后植骨区域较对侧正常下颌骨有明显的核素浓聚.核素计数比值半定量分析发现术后2 周时,植骨区和对照侧核素计数比值最大,此后呈逐渐下降趋势.结论:快速成型支架结合自体骨移植植入下颌骨缺损区后,植骨块能够成活.利用核素骨显像监测金属支架内移植骨成活的方法是可行的.     

鸵鸟骨转化多相钙磷陶瓷支架负载骨髓基质细胞异位成骨性能研究

目的：观察鸵鸟骨转化多相钙磷陶瓷复合骨髓基质细胞后植入裸鼠皮下的成骨性能。方法：获取兔髂骨松质骨骨髓基质细胞，体外分离、扩增、诱导后接种于多相钙磷陶瓷支架。支架／细胞复合物植入裸鼠背部皮下，单纯支架材料植入作为对照。植入后4周、8周取材，通过大体、组织学观察评价成骨活性。结果：支架／细胞复合物植入后4周，新骨主要以软骨为主，部分区域见少量成熟骨，可见软骨内成骨方式。植入后8周，材料表面和孔隙内有更多的成熟骨形成，部分区域有血管和多核巨细胞分布。结论：支架／细胞复合物显示良好的成骨活性，鸵鸟骨转化多相钙磷陶瓷可以用于骨组织工程支架材料。     

无机诱导因子复合性支架材料修复骨缺损的组织学观察

目的:应用无机诱导因子复合性支架材料修复山羊的下颌骨角部大型箱状缺损,研究该材料的成骨性能,探讨其在骨组织工程中的应用价值。方法:山羊15只,按4、8、12周3个时间点分为3组,于双侧下颌角手术制备30mm×25mm×10mm的大型箱状缺损,采用自身配对设计,左侧置入支架材料(A组),右侧空白对照(B组)。术后4、8、12周分别处死动物,取缺损修复区和材料—骨界面标本,观察组织动态学。结果:!4～12周A组有进行性成骨、钙化、骨髓形成的过程,而B组骨缺损内为未充满的纤维结缔组织,下缘有不成熟的软骨细胞附着。结论:支架材料有相当良好的生物活性;修复骨缺损显示优良的修复效果;具有临床应用的可行性。     

无机诱导因子支架材料行颌骨重建的放射学评价

目的:在实验外科的基础上,用预制型无机诱导因子复合性支架材料对颌骨缺损行修复重建,从放射学角度评价组织工程化骨构建的效果。方法:实验组对15只山羊下颌角缺损(30mm×25mm×10mm大小)以预制型支架材料修复,左侧为实验组,右侧为空白对照组,术后分别于4、8、12周处死5只动物行X线检查。临床应用组31例,分别于术后5d、1、2、3、6个月摄取下颌骨全景片和CT,观察骨缺损区的新骨形成情况,并按X线分级评分、6点法和X线阻射密度测量的评分标准测评,对各组的X线评分值及阻射密度值进行t检验。结果:实验组骨缺损放射影像评分及新生骨情况在4、8、12周显著优于对照组,空白对照组12周时骨缺损区均无明显骨修复现象。临床应用组发现组织工程骨表现出随时间的增长,成骨量逐渐增加的特征,在6个月时,阻射静止期有骨髓重建X线像。结论:预制型无机诱导因子复合性支架材料具有优良的成骨效果,放射学检查对骨缺损的评估有重要意义。     

同种异体下颌骨移植修复犬颞颌关节、下颌骨的放射性核素和骨密度观察

目的：通过放射性核素和骨密度检查,观察犬同种异体下颌骨移植后的愈合情况。方法：18只杂种犬随机分成3组,分别接受自体骨、冷冻同种异体骨、冷冻干燥同种异体骨移植,术后4周、12周、24周分别进行放射性核素检查;术后24周处死所有动物,对髁突、升支中段、下颌角进行骨密度扫描,并与移植前的骨密度比较。结果：术后4周、12周、24周移植侧的RO I平均计数均高于对照侧,异体骨组术后12周的T/NT比值显著高于其他时间点;自体移植骨髁突的骨密度显著高于对照,异体冷冻干燥骨/冷冻骨移植术后24周的骨密度没有明显改变。结论：犬同种异体冷冻/冻干下颌骨移植后可以重新血管化,术后24周时骨改建已经趋缓;犬冷冻/冻干异体下颌骨移植24周后的骨密度变化不大。     

复合血管内皮细胞组织工程骨修复兔下颌骨缺损的研究

目的探讨血管内皮细胞构建的组织工程骨修复兔下颌骨缺损。方法实验分为三组,A组：兔成骨细胞（rabbit osteoblast,ROB）和血管内皮细胞（rabbit vascular endothelial cell,RVEC）复合外消旋聚乳酸（poly-DL-lacide,PDLLA）;B组：单纯成骨细胞复合PDLLA,C组：单纯PDLLA。分别修复兔下颌骨缺损,手术后4周、8周通过形态学、X线观察骨缺损修复及血管化情况。结果A组骨组织形成与血管化程度均高于B组,在材料中心区可见有血管形成,越靠近血管成骨越多。X线观察,A组：骨缺损区阴影面积明显减小,材料植入区可见骨组织影像;B组：缺损面积减小,骨组织影像增加,中心区影像低于周围区域。C组：缺损区未见骨组织影像,周围可见骨痂形成。结论复合血管内皮细胞和成骨细胞的细胞支架复合体无论在成骨还是血管化方面均好于单纯成骨细胞复合支架植入组。     

纳米晶羟基磷灰石复合胶原材料在拔牙创修复中的作用

目的:探讨纳米晶羟基磷灰石复合胶原材料(nHAC)在拔牙创修复中的作用。方法:拔除12只成年狗两侧下颌第二及第三切牙,并去除牙槽间隔,一侧随即植入nHAC,对侧植入致密多晶羟基磷灰石微粒人工骨(HA)作为对照。于植入后4、8、12周分别取材,采用99mTc MDP核素骨显像、组织学观察、图像分析等方法比较两种植入材料在牙槽窝中的骨修复能力。结果:nHAC植入牙槽骨后,材料被逐渐降解吸收,新骨不断生成,12周后植入材料几乎完全被成熟的骨组织取代;图像分析结果显示不同时间nHAC组新骨形成的比值显著高于HA组(P<0.01);4、8、12周nHAC组浓聚程度均高于HA组。结论:nHAC在修复拔牙创缺损时比HA效果更好,是一种较为理想的骨替代材料。     

无机活性元素组织工程支架材料重建修复山羊颌骨缺损的扫描电镜观察

目的:用扫描电镜观察无机活性元素组织工程支架材料构建的组织工程骨及其修复羊大面积颌骨缺损的体内成骨状况.方法:实验组对15只山羊下颌角缺损(30 mm×25 mm×10 mm大小)以支架材料修复,左侧为实验组,右侧为空白对照组,术后分别于1、3、6个月处死5只动物行扫描电镜及生物化学检查,观察无机活性元素组织工程支架材料体内成骨情况.结果:实验组骨缺损新生骨在1、3、6个月显著优于对照组,空白对照组6个月骨缺损区均无明显骨修复现象.结论:应用扫描电镜观察到无机活性元素组织工程支架材料具有优良的成骨效果.     

无机诱导因子复合性骨支架材料的生物相容学研究——兼论人体外复合细胞相容性观察

目的用预制型无机诱导因子复合性骨组织工程支架材料对实验动物山羊的下颌骨角部大型箱状缺损行骨重建，评价其及其降解产物对血液和植入区周围组织的生物相容性反应；和人体外复合细胞培养的生物相容性观察。方法15只雌性山羊作为实验组，术后4，8，12w处死动物对相关重要脏器进行大体解剖学和组织病理观察；另取雌性山羊15只作为对照组；培养人骨髓基质细胞行细胞形态、电镜和MTT观察。结果血液学检测，实验组与对照组均在正常值范围内，两组间差别无统计学意义；实验组重要脏器组织病理学未见形态改变和炎性细胞浸润；支架置入区域病检符合组织工程骨的愈合过程；人体外复合细胞培养的检测中未见明显异常。结论生物相容性观察提示：本支架材料无急慢性毒性反应和超敏反应，对人骨髓基质细胞的形态、生长和增殖无明显抑制作用，具有良好的生物相容性。     

冷冻异体硬脑膜引导骨组织再生的动物实验及在口腔种植中的临床应用研究

探索利用冷冻处理异体硬脑膜引导种植体周围骨组织再生的可能性。12只日本大耳白兔 ,在双侧下颌下缘造成骨缺损 ,右侧覆盖兔冷冻异体硬脑膜 ,左侧不覆膜 ;临床用于种植体周围骨缺损24例 ,采用人异体冷冻硬脑覆盖。结果实验动物伤口均I期愈合。组织学观察实验侧4周时骨表面有柱状骨突起 ,18周改建为成熟骨 ;对照侧明显慢于实验侧。临床患者骨修复良好 ,其中15例(16区)裂隙状骨缺损修复率达87.8 %。冷冻异体硬脑膜是一种较理想的引导骨组织再生膜材料     

无机诱导因子复合支架材料修复狗牙槽骨缺损的初步观察

目的观察无机诱导因子在狗牙槽骨缺损修复中的作用效果。方法在5只狗双侧下颌第1、2前磨牙牙周，制备1．0cm高的全牙槽骨缺损，植入无机诱导因子，在术后2、3个月随机选取2只狗，分次取材后进行影像和组织学评价。结果无机诱导因子植入1周后，软组织愈合正常，2个月后缺损区X线影像开始出现阻射，牙槽嵴高度变化不明显，部分牙周膜影消失，硬组织切片观察到新生牙槽骨与牙根直接连接，形成骨结合，3个月时尚可见到未完全降解材料。结论无机诱导因子促进了牙槽骨成骨，可作为修复牙槽骨缺损的人工骨替代材料。     

自体颏外板在眶底骨折缺损重建中的应用

目的 探讨自体颏外板修复眶底骨折缺损的效果。方法 对11例眶底骨折缺损患者,采用自体下颌骨颏外板进行眶底重建修复,术后随访6~12月。结果 11例患者术后伤口均一期愈合,眶底结构恢复,无视力下降和眼球运动受限,移植物均无感染排出或吸收,供区无并发症发生。结论 自体颏外板是眶底骨缺损较为理想的一种修复材料。     

Healing of large dentofacial defects

Dentofacial defects can be small or very large, consisting of defects in the craniomaxillofacial region with missing soft tissue, bony and other hard tissue components. Such combined mucosal, osseous and even cartilaginous defects can be reconstructed using flaps and bone grafts, or hopefully, in the future with bone graft substitutes or even tissue engineered constructs. The healing of such wounds always relies on the vascularity of the surrounding tissues. This chapter seeks to provide a physiological basis for the mechanisms involved in the healing of such large complex defects. The reconstruction of specific defects must follow sound and logical surgical principles. The authors employ the concept of the reconstructive surgical ladder, in which techniques of step‐wise increasing complexity are used with a strong preference for the simplest possible procedure at the outset. A number of techniques are presented along with the principles of tissue engineering and the basis for bone regeneration using adipose derived stem cells, growth factors and resorbable scaffolds.     

The effect of enamel matrix proteins on periodontal regeneration as determined by histological analyses

BACKGROUND: Therapeutic approaches to periodontal regeneration in the past have utilized bone replacement grafts, growth factors, barrier membranes, or combinations of these approaches. More recently, enamel extracellular matrix proteins have been introduced to stimulate periodontal regeneration. One factor thought to have an impact on the outcome of the regenerative process is the initial size of the periodontal defect. This is particularly the case when using proteins to stimulate regeneration, because the concepts of guided tissue regeneration emphasize the need for space maintenance to allow for selected cell repopulation. The goal of this study was to evaluate periodontal regeneration in intrabony defects of various sizes treated with enamel matrix proteins. METHODS: Periodontal defects ranging in size from 1 to 6 mm were created bilaterally around 3 teeth in the mandibles of baboons. Plaque was allowed to accumulate around ligatures placed into the defects. After 2 months, the ligatures were removed, the teeth were scaled and root planed, and a notch was placed at the base of the defect. On one side of the mandible, neutral ethylene diamine tetracetic acid and enamel matrix proteins were used to treat the defects. The other side served as a control, with neutral ethylene diamine tetracetic acid treatment alone after scaling and root planing. Flaps were sutured and the animals were allowed to heal without oral hygiene procedures. After 5 months, the animals were sacrificed and the teeth were processed for histological evaluation. RESULTS: Periodontal regeneration occurred in all sizes of the periodontal defects. Qualitatively, new cementum, periodontal ligament with Sharpey's fibers, and new bone tissue were observed. In general, enamel matrix protein treatment resulted in greater tissue formation than controls. In many instances, dramatic tissue formation occurred far coronal to the base of the defects. In addition, horizontal bone fill occurred in defects that were initially 4 or 6 mm wide. The resultant width of the periodontal ligament was similar in all defects regardless of the original defect width. The cementum width was slightly greater in the wider (4 and 6 mm) defects compared to the more narrow (1 and 2 mm) defects. When evaluating the combined 1 and 2 mm defects, the height of new cementum with enamel matrix protein treatment was 45% greater than the control, with 31% greater new bone height versus the control. In the combined wider defects (4 and 6 mm), new tissue height was more similar between enamel matrix protein-treated defects and control defects. The results from the wider defects must be interpreted cautiously, because the interproximal bone heights were resorbed more adjacent to the wider defects during the plaque accumulation period and likely limited the potential for regeneration. CONCLUSIONS: The treatment of various sized periodontal defects with enamel matrix proteins stimulated substantial periodontal regeneration. In many cases, dramatic amounts of new cementum, Sharpey's fibers, periodontal ligament, and bone tissue were formed far coronal to the notch at the base of the defect, especially considering the width of the original defects. This periodontal regeneration occurred in the absence of exogenous growth factors, bone replacement grafts, barrier membranes, or their combination.     

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     

Incorporation of composite bone implants in the facial skeleton

The purpose of this study was to evaluate the capacity of composite grafts consisting of either particulated cancellous or particulated cortical bone and anorganic bovine bone mineral (BBM) (Bio-Oss) to induce regeneration in standardized critical size bony defects overlying the frontal sinus. Four full thickness critical size bone defects were made in the frontal bone in each of 8 skeletally mature female goats. These defects were filled at random with composite cancellous bone/BBM grafts or composite cortical bone/BBM grafts. Control defects were not included but could be evaluated using data from a previous study in which the same experimental setting was used (Merkx et al. 1999a). Fluorochrome bone markers were injected subcutaneously 1 and 5 weeks after implantation, and 1 week before the animals were killed. Two animals were killed at 3, 6, 12 and 24 weeks after surgery respectively. The results were evaluated by histological means including fluorescence microscopy. In conclusion, composite grafts consisting of autogenous cancellous bone/BBM yield good results, combining the advantages of each material alone and reducing the disadvantages of each when used separately. Critical size defects in the maxillofacial area, overlying a paranasal sinus, filled with this material heal uneventfully within 12 weeks. Composite grafts consisting of cortical bone and BBM show less favorable results. These grafts induce osteoclasts, probably by the presence of non-functional BBM, resulting in resorption of the cortical bone chips.