羟基磷灰石涂层种植体─骨界面的生物力学研究

本项研究选用氧化铝作为种植体基体，在８５０℃和１０５０℃下分别在其表面烧结羟基磷灰石（简称ＨＡ），制成ＨＡ１和ＨＡ２涂层种植体，以纯钛作对照。狗股骨穿皮质种植１、３、６个月后取材，行顶出试验，并对测试后的破坏断面行扫描电镜观察。结果发现：两种ＨＡ涂层种植体具有较好的生物力学性能，能在种植早期加速新骨形成、钙化，达到较高的界面结合强度；涂层种植体在顶出试验后，断裂发生在涂层材料内，而纯钛则发生在种植体一骨组织界面；涂层种植体的界面力学性能和烧结温度有关，ＨＡ２涂层种植体在各种植程期的界面结合强度均高于ＨＡ１涂层种植体。     

羟基磷灰石烧结涂层种值体和纯钛种植体的对比实验研究

将相同大小的ＨＡ１涂层种植体（涂层烧结温度８５０℃）、ＨＡ２涂层种植体（涂层烧结温度１０５０℃）和Ｔｉ种植体植入狗股骨１、３、６个月，行界面形态学、定量组织学及生物力学测试，结果发现：１、Ｔｉ种植体和涂层种植体均具有良好的生物相容性，能和骨组织形成良好的骨性结合，其中涂层种植体能在种植早期加速界面骨性结合的形成．界面强度高于纯钛．涂层种植体－骨组织界面受剪切力破环后，断裂面在涂层材料内；而Ｔｉ种植体则断裂在种植体－骨组织界面．２、ＨＡ涂层的生物活性与烧结温度有关，ＨＡ２涂层在各种植程期均显示出比ＨＡ１更好的生物活性和界面强度。３、ＨＡ烧结涂层具有良好的生物稳定性，种植６个月后未见明显降解吸收。研究表明：ＨＡ烧结涂层种植体具有良好的生物活性和生物力学性能，是比较理想的种植材料。     

羟基磷灰石烧结涂层种植体和纯钛种植体的对比实验研究

将相同大小的ＨＡ１涂层种植体（涂层烧结温度８５０℃）、ＨＡ２涂层种植体（涂层烧结温度１０５０℃）和Ｔｉ种植体植入狗股骨１、３、６个月，行界面形态学，定量组织学及生物力学测试，结果发现：１、Ｔｉ种植体和涂层种植体均具有良好的生物相容性，能和骨组织形成良好的骨性结合，其中涂层种植体能在种植早期加速界面骨性结合的形成，界面强度高于纯钛。涂层种植体一骨组织界面受剪切破坏后，断裂面在涂层材料内，而Ｔｉ种植体     

羟基磷灰石涂层种植体骨愈合的实验研究

目的：通过动物实验，研究涂覆烧结工艺技术研制的新型羟基磷灰石（HA）涂层种植体的骨愈合情况。方法：将12颗钛种植体（6颗有HA涂层，6颗无涂层）植入6只成年杂种犬下颌骨内，分别饲养1、3、6个月，使种植体在无负荷的条件下愈合。标本进行大体观察、光镜组织学观察以及计算机定量组织形态学评价。结果：两种种植体都能产生骨结合。有涂层的种植体新骨的产生和成熟都比无涂层的钛种植体更为迅速。术后1、3、6个月有涂层种植体的骨结合率分别为71．68％、86．81％、90．19％；无涂层种植体的骨结合率为53．26％、66．16％、68．72％，其间有显著性差异（P＜0．01）。结论：涂覆烧结工艺HA涂层骨内种植体能取得良好的骨结合，涂覆烧结工艺HA涂层能够很好地促进种植体的骨结合。     

正畸支抗种植体骨整合与稳定性的实验研究

目的　考察正畸支抗种植体的骨整合与稳定性以及二者之间的关系。方法　将HA涂层钛种植体、钛浆喷涂钛种植体、未涂层钛种植体植入狗股骨 ,愈合期后施加 1 96N正畸力 2个月。测量施力后种植体的位置变化和种植体—骨界面的剪切结合强度 ,用扫描电镜观察界面。结果　 3种种植体位移分别为 (- 0 5 0± 1 78)mm、(- 0 0 5± 1 76 )mm、(0 2 9± 1 77)mm ,统计学分析结果显示 ,还不能认为 3种种植体出现移动。 3种种植体—骨界面的剪切结合强度分别是 (2 88± 0 5 5 )MPa、(1 89± 0 81)MPa和 (2 14± 0 49)MPa。HA涂层种植体与骨紧密结合 ,其界面结合强度最高 ;另外 2种种植体与骨的结合强度差异无显著性。结论　虽然HA涂层种植体与骨结合最牢固 ,但 3种种植体—骨界面均可形成骨整合 ,在常规正畸力作用下不会发生明显移动。本项研究结果表明 ,种植体可用作短期的正畸支抗。     

羟基磷灰石涂层的氧化锆陶瓷骨内种植实验初步研究

将烧结涂层的羟磷灰石-氧化锆复合生物陶瓷种植体及纯钛种植体按低创伤手术原则植入犬股骨。三个月后取标本进行骨一种植体结合强度试验，作含复合陶瓷种植体的不脱钙组织切片光镜观察，扫描电镜观察及Ca、P、Zr元素探针检测分析．结果表明，复合陶瓷—骨给合强度，显著高于钛—骨结合强度；复合陶瓷与骨组织结合紧密，界面无纤维结缔组织间隔，说明该材料具有极好的生物相容性。考虑到氧化锆陶瓷有着优良的机械性能，预计该复合生物陶瓷材料可能具有良好的发展前景。     

生物陶瓷涂层复合种植体骨界面的剪切强度

本文以恒河猴为实验对象,以未涂层纯钛种植体为对照,用力学测试方法研究两种生物活性玻璃陶瓷涂层种植体植入股骨后,种植体——骨界面的剪切强度。结果表明:两种生物活性玻璃陶瓷涂层种植体,与未涂层种植体相比,在种植早期较快与骨形成牢固的结合。其中,又以M—涂层种植体更明显,它的平均界面剪切强度,在种植后3个月是未涂层者的2至3倍。     

Ti—75合金作为复合种植体基底材料的实验研究

目的：观察复合种植体（CI）基底材料Ti-75合金（TA）的生物学特性和TA－涂层结合强度在种植体骨界面结合强度中的表现。方法：应用穿皮质骨种植模型。在双侧犬股骨内种植TA和CI共32枚；在术后3个月和6个月,处死动物取材；种植体骨界面进行组织学观察和推出试验，并对断裂后的种植术骨界面进行扫描电镜观察。结果：TA与CI均与骨组织形成了骨柱结合；CI骨界同的剪切强度高度于TA（P＜0．01）；CI骨界面断裂在部分在涂层骨组织界面和涂层内部，很少在涂层TA界面。结论：TA与CI均具有良好的生物相容性；TA涂层界面具有足够的结合强度，是值得进一步研究的复合种植体基底材料。     

矫形力对羟基磷灰石涂层的钛支抗种植体骨界面影响的研究

目的：了解在矫形力作用下的HA涂层钛种植体骨界面情况。方法：在狗下颌骨延期植入8枚种植体，施以2.9N和5.9N的矫形力，通过三色荧光标记和组织学切片的形态学研究支抗种植体骨界面情况。结果：HA涂层钛支抗种植体在矫形力作用3个月后仍然稳定，种植体界面为骨整合,2.9N与5.9N矫形力对种植体周围骨改建的影响无差别。结论：HA涂层种植体在短期内受矫形作用下稳定，可用做正畸矫开支抗。     

生物活性陶瓷-钛复合种植体研究

种植作的表面形态与结构对种植效应起着决定性的影响。本文通过烧结涂层技术在钛基体表面涂层生物活性陶瓷膜层，制作成BTC复合种植体。经测定，其瓷层厚度80～100μm，瓷层－基体间的压剪强度27．1±4．9MPa，生物安全性实验及动物实验表明，其完全符合生物医用植入材料的各项指标。与裸钛种植体相比，可提前一个月实现骨性结合。实验证实BTC是一种生物相容性好，金－瓷结合强度高的理想的复合种植体。     

Experimental study on the Biomaterial/Porous Titanium composite dental implants]

This study investigated the tissue compatibility of bone morphogenetic protein (BMP) /biologic ceramic/porous titanium implant,BMP/porous titanium implant,biologic ceramic/porous titanium implant and porous titanium implant by LM,SEM,EDXA.The results showed that the new bone formation and new bone mature were earlier in the BMP composite implants treated group.BMP uncomposite implants had no evident difference in the time of new bone formation, but the interface bonding ways had significant difference.     

Failure analysis of fractured dental zirconia implants

Objectives: The purpose of the present study was the macroscopic and microscopic failure analysis of fractured zirconia dental implants. Methods: Thirteen fractured one‐piece zirconia implants (Z‐Look3) out of 170 inserted implants with an average in situ period of 36.75±5.34 months (range from 20 to 56 months, median 38 months) were prepared for macroscopic and microscopic (scanning electron microscopy [SEM]) failure analysis. These 170 implants were inserted in 79 patients. The patient histories were compared with fracture incidences to identify the reasons for the failure of the implants. Results: Twelve of these fractured implants had a diameter of 3.25 mm and one implant had a diameter of 4 mm. All fractured implants were located in the anterior side of the maxilla and mandibula. The patient with the fracture of the 4 mm diameter implant was adversely affected by strong bruxism. By failure analysis (SEM), it could be demonstrated that in all cases, mechanical overloading caused the fracture of the implants. Inhomogeneities and internal defects of the ceramic material could be excluded, but notches and scratches due to sandblasting of the surface led to local stress concentrations that led to the mentioned mechanical overloading by bending loads. Conclusions: The present study identified a fracture rate of nearly 10% within a follow‐up period of 36.75 months after prosthetic loading. Ninety‐two per cent of the fractured implants were so‐called diameter reduced implants (diameter 3.25 mm). These diameter reduced implants cannot be recommended for further clinical use. Improvement of the ceramic material and modification of the implant geometry has to be carried out to reduce the failure rate of small‐sized ceramic implants. Nevertheless, due to the lack of appropriate laboratory testing, only clinical studies will demonstrate clearly whether and how far the failure rate can be reduced. To cite this article:
Gahlert M, Burtscher D, Grunert I, Kniha H, Steinhauser E. Failure analysis of fractured dental zirconia implants.
Clin. Oral Impl. Res. 23 , 2012; 287–293
doi: 10.1111/j.1600‐0501.2011.02206.x     

Some advances in endosseous implants

A major advance in endosseous implantology hinges on the coating of titanium implants by porous biodegradable, bioreactive tricalcium phosphate ceramic. When implanted into alveolar bone by a careful technique, the ceramic is resorbed to be replaced by bone. As a result, the endosseous implant becomes ankylosed to the bone. This represents a stable implant/bone interface as opposed to the unstable connective tissue interface that encapsulates many other implant devices.     

钛种植体表面微弧氧化处理后的生物力学及组织形态学研究

目的对表面微弧氧化(MicroarcOxidation ,MAO)处理后的纯钛种植体进行动物种植实验研究,评估改进的MAO工艺应用于钛种植体的实际效果。方法建立犬下颌缺牙模型,设计纯钛材料种植体,分别经两种MAO处理(MAO - 1和MAO - 2 )后,植入犬下颌骨,采用拉出测力实验、扫描电镜观察、种植体-骨界面X射线能谱扫描的研究方法,对植入3、6、12周种植体的生物力学稳定性及界面特点进行评价,以未经处理纯钛种植体作为对照,实验数据以SPSS软件进行统计分析。结果各组种植体的骨结合力随时间逐渐升高,在所测试的3个时间点内,各组间的骨结合力都有明显统计学差异,MAO - 1组>MAO - 2组>纯钛对照组;X射线扫描结果表明,MAO处理后的种植体-骨界面附近钙磷含量较高,提示新生骨基质钙化良好。结论MAO处理工艺可以提高种植体表面氧化层的生物活性,纯钛种植体经改进的MAO处理后的可以进一步缩短骨结合时间,提高骨结合力。     

管状骨种植骨结合的实验研究

目的 研究管状骨种植后的组织学以及生物力学变化,为临床应用提供理论依据.方法 采用6只成年山羊,每只羊的左后肢胫骨手术放置4只种植体.采用影像学、四环素标记评价种植后的变化,术后1、2、3个月各宰杀2只动物,切取实验标本,制备成硬组织切片及扫描电镜标本进行观察,同时对剩余的标本采用推出实验进行生物力学分析.结果 术后1个月,在种植体两端与胫骨的结合部位,种植体周围被新形成的编织骨包绕,四环素标记显示新骨形成活跃.种植体-骨界面结合率的平均值为60.13%,种植体承受的推出力相对较小,为435 N左右.术后3个月,与种植体结合部位的骨组织已经改建,且与正常皮质骨相同,排列方向与种植体轴向平行,种植体-骨界面结合率的平均值为61.61%.种植体承受的推出力达1113 N左右.结论 管状骨种植后,种植体-骨界面仅发生在双皮质结构区;种植后3个月时骨改建完毕,能够承受较大的负载.     

Potential application of high-resolution microfocus X-ray techniques for observation of bone structure and bone-implant interface

PURPOSE: The aim of the present study was to evaluate the potential application of 2 types of microfocus x-ray units to study the bone structure around dental implants and at the bone-implant interface. MATERIALS AND METHODS: IMZ titanium implants were placed in the maxilla and mandible of a beagle dog. After implantation periods of 1, 2, and 3 months, the bone-implant interface was evaluated with microfocus x-ray computed tomography (CT) and microfocus x-ray fluoroscopy. RESULTS: Microfocus x-ray CT images of the bone-implant specimen at 3 months after implant placement revealed a clear distinction between the implant and the bone. The implant surface was partially covered with bone, and direct contact between the implant and bone could be clearly seen. Differences in degrees of calcification were identified by the differences in relative black and white intensity. Microfocus x-ray fluoroscopy also showed clear features of the bone and titanium implant The original drill hole and new bone formation could be recognized. These findings corresponded with traditional histologic observations by light microscopy. DISCUSSION AND CONCLUSION: Microfocus x-ray techniques are non-destructive and require a very short examination time. They are considered useful to observe details of the bone structure and bone-implant interface. Microfocus x-ray fluoroscope and microfocus x-ray CT techniques can provide a clear and distinguishable image of the bone-implant interface because of their high spatial resolution.     

Impact Fracture Resistance of Two Titanium‐Abutment Systems Versus a Single‐Piece Ceramic Implant

Background: The number of patients with oral implants has increased significantly. However, the literature addressing the effect of impact force on titanium and/or ceramic implants is inconclusive. This study sought to determine the fracture resistance to impact load of titanium and ceramic endosseous oral implants. Materials and Methods: Endosseous oral implants were vertically positioned in two different mounting media: brass and a bone‐simulation material. The implant configurations tested included an experimental one‐piece Y‐TZP implant and a commercially available titanium implant (external hex) with both titanium and zirconia abutments. The specimens were subjected to an impact load using a pendulum impact tester with tup weights varying from 0.9 to 4.5 kg delivered at a radius of 40.64 mm. Loads were delivered to the abutment at a point 4.27 mm above the implant fixture and block junction. Statistical differences (p < .05) were established using the F‐test for variances and, when different, t‐test assuming unequal variances. Results: For implants clamped in brass, the titanium implant with titanium abutment required the greatest energy to fracture the implant‐abutment system (only the abutment screw failed). The ceramic implant and ceramic abutment on titanium implant presented the lowest fracture energy (p < .01). No significant differences were observed when different systems were inserted into the foam blocks of the bone substitute (p > .25). Conclusion: This investigation showed that the fracture energy of two titanium‐abutment systems versus a single‐piece Y‐TZP implant in foam blocks simulating bone elastic modulus was not different, and that differences occurred when the embedding material elastic modulus was increased an order of magnitude.     

Light and transmission electron microscopy of the intact interfaces between non-submerged titanium-coated epoxy resin implants and bone or gingiva.

This experiment was aimed at studying the intact tissue/implant interface of non-submerged dental implants with a titanium surface. Epoxy-resin replicas were fabricated from 3.05 x 8 mm cylindrical titanium implants with a plasma-sprayed apical portion and a smooth coronal collar. The replicas were coated with a 90-120-nm-thick layer of pure titanium and autoclaved. The coated replicas were inserted as non-submerged endosseous implants in the edentulous premolar region of dog mandibles and allowed to heal for three months. Jaw sections containing the implants were processed for light and electron microscopic study of the intact tissue/implant interface with and without prior demineralization. Gingival connective tissue fibers were closely adapted to the titanium layer, in an orientation more or less parallel to the implant surface. There was no evidence of any fiber insertions into the surface irregularities of the smooth or rough titanium surface. Undemineralized bone was intimately adapted to the titanium surface without any intervening space. In demineralized sections, the collagen fibers of the bone matrix tended to be somewhat thinner and occasionally less densely packed in the vicinity of the implant surface. However, they extended all the way to the titanium surface, without any intervening fibril-free layer.     

In vitro evaluation of push-out bond strength of direct ceramic inlays to tooth surface with fiber-reinforced composite at the interface

STATEMENT OF PROBLEM: Failure of a restoration, where a part of a ceramic inlay and/or a cusp is fractured, is a common clinical problem. The application of fiber-reinforced composites at the tooth-inlay interface may prevent undesirable fractures in dental restorations. There is little information regarding the effect of a fiber- reinforced composite layer on the push-out bond strength of ceramic inlays to tooth structure. PURPOSE: The purpose of this study was to compare push-out bond strengths of ceramic inlays to tooth structure using a layer of fiber weave-reinforced composite at the tooth interface with different adhesive systems. MATERIAL AND METHODS: Forty standardized occlusal, conically-shaped cavities, 5 mm in occlusal diameter, 3.5 mm in cervical diameter and 3.5 mm deep, were prepared in extracted human molars using a truncated cone-shaped diamond rotary cutting instrument, the dimensions of which corresponded with those of prefabricated ceramic inlays. The teeth were divided into 2 groups according to the adhesive system used. Solobond Plus was used as a total-etching system and Futurabond NR as a self-etching system. Preetched and silanized ceramic inlays were bonded to tooth structure with or without a layer of bidirectional fiber weave (StickTech). The groups without fiber-reinforced composite layer served as controls. The inlays were cemented with dual-polymerizing luting composite (Bifix QM) and light polymerized for 40 seconds from the buccal, lingual, and occlusal surfaces. Specimens were thermal cycled (6000 x 5 degrees -55 degrees C) and 3.5-mm-thick discs were prepared for the push-out test. The discs (n=10) were tested in a universal testing machine and pushed out with a cross-head speed of 1.0 mm/min. The data were analyzed with analysis of variance (ANOVA) (alpha=.05). Failure modes were analyzed using a stereomicroscope and SEM. RESULTS: Push-out mean bond strength (SD) values in MPa of direct ceramic inlays were: Solobond Plus (control): 9.7 (3.9), Solobond Plus with fiber-reinforced composite: 10.5 (5.0), Futurabond NR (control): 8.4 (2.5), Futurabond NR with fiber-reinforced composite: 8.6 (2.2). The differences between groups were not significant for either adhesive system or with the use of fiber-reinforced composite layer at the interface. Mixed failures were observed in the control groups, whereas in the fiber-reinforced composite layer groups, failures were mostly cohesive within the fiber layer. No cohesive fracture of the tooth was observed when a layer of fiber weave was placed at the interface. CONCLUSION: Within the limitations of this in vitro study, a fiber-reinforced composite layer at the bonding interface of ceramic inlay did not influence the push-out bond strength. Futurabond NR self-etching system and Solobond Plus total-etching system demonstrated similar push-out bond strengths.     

3D打印多孔钽种植体对骨整合影响的实验研究

目的 研究多孔钽及多孔钛种植体对骨整合的影响。方法 通过计算机辅助设计方法建模,采用3D打印技术制备两种微孔参数相同的多孔材料种植体：多孔钽及多孔钛。在24只新西兰大白兔双侧股骨外踝处建立骨缺损模型,每只动物左右侧缺损随机分组,分别用多孔钽（实验组）和多孔钛（对照组）种植体进行修复。种植体植入后2、4、8周取材,进行大体观察和亚甲基蓝-酸性品红染色,观测种植体和骨界面的骨整合情况,采用推出实验测试种植体-骨界面结合强度。 结果 术后2、4、8周,两组材料界面的新生骨组织逐渐增加,出现新生骨小梁并向材料孔隙内生长;两组的成骨情况及种植体-骨组织界面结合强度的差异无统计学意义（P>0.05）。结论 3D打印的多孔钽能与骨组织形成早期的生物结合,具有与多孔钛相当的骨整合能力。