早期不同时间种植体骨界面改建的骨组织定量测定

目的建立种植体植入Beagle犬下颌骨的动物模型,应用Micro-CT对早期的种植体周围骨组织情况进行分析研究。方法选用4只健康纯系雄性Beagle犬,随机分A、B两组,拔除下颌双侧第4前磨牙、第1磨牙,3个月后在相应缺牙区植入8枚植体,分别在植入后2周、4周处死两只Beagle犬,并对其作相应临床检查及Micro-CT检测。结果各组实验犬拔牙创愈合良好,种植体成功植入相应拔牙位点,各项临床指标无明显差异,Micro-CT检测显示种植体植入后2周的骨体积分数大于植体植入后4周的骨体积分数,且两组具有显著统计学差异(P≤0.01),其余骨微结构计量无统计学差异。结论成功建立口腔种植Beagle犬动物实验模型,早期植体周围骨愈合是一个骨吸收骨生成的骨组织改建或骨组织修复过程,植体植入后4周其周围骨吸收大于骨生成,Micro-CT能很好地应用于口腔种植骨微结构分析研究。     

TM种植体-骨结合界面的显微CT观察

目的 研究TM种植体-骨结合界面及其上 1/3倒楔形间隙的成骨情况.方法 用医用钝钛钛棒加工成两组种植体,实验组为锥度5.44°、表面进行喷砂酸蚀处理的TM种植体,锥度从种植体上1/3处开始变化;对照组为仿straumann的表面喷砂酸蚀(sandblast large grit and acid-etching,SLA)圆柱状螺纹种植体.建立Beagle犬下颌骨种植模型,3只犬每只植入实验组TM种植体和对照组仿straumann -SLA圆柱状螺纹种植体各4枚,3只实验犬分别于4周、8周和12周处死,截取下颌骨行显微CT三维重建,观察种植体-骨结合界面及上1/3间隙的成骨情况.结果 8周时实验组TM种植体上1/3倒楔形间隙开始有骨修复,12周时对照组仿straumann-SLA种植体颈部骨质有吸收迹象,实验组TM种植体颈部骨质仍得到良好保存.结论 TM种植体能形成良好骨结合界面,体部上1/3的锥度设计可保存颈部皮质骨.     

富血小板血浆在种植体周围骨缺损修复中的实验研究

目的:探讨富血小板血浆(platelet-richplasma,PRP)、PRP复合骨诱导活性材料(osteoinduction active material,OAM)对种植体周围骨缺损修复的作用。方法:Beagle犬4只,拔除每只犬一侧下颌第一、二前磨牙及其双侧下颌第四前磨牙作为实验牙位。3个月后拔牙处植入种植体,每只犬共植入3颗种植体,第一、二前磨牙牙位植入1颗种植体为对照组,对侧第四前磨牙牙位植入1颗种植体为实验A组,同侧第四前磨牙牙位植入1颗种植体为实验B组。种植术中同期制备种植体周围骨缺损并植入相应骨移植材料:A组植入PRP/OAM;B组植入PRP/磷酸三钙;对照组植入磷酸三钙。种植术后8、16周处死动物,进行组织学观察,测量种植体周围骨密度,采用SPSS13.0软件对数据进行单因素方差分析。结果:8周时,实验A组新骨与种植体形成区段性骨结合;实验B组种植体边缘可见新骨形成,但量较少;对照组种植体边缘为纤维性界面。8周时骨密度测量,各组间骨密度差异无统计学意义。16周时,实验A组可见哈佛系统,实验A、B组新骨与种植体形成骨整合;对照组仅为纤维性结合。16周时骨密度测量,两实验组骨密度均显著高于对照组。结论:PRP及PRP/OAM可促进种植体周围骨缺损修复。     

骨诱导活性材料复合富血小板血浆修复犬种植体周围骨缺损

目的从组织学角度评价骨诱导活性材料(osteoinduction active material,OAM)复合富血小板血浆(platelet-rich plas-ma,PRP)对种植体周围骨缺损的修复效果。方法Beagle犬4只,拔除下颌1、2、4前磨牙。每只犬左右两侧实验牙位随机分为实验侧和对照侧,实验侧第4前磨牙牙位为实验A组,第1、2前磨牙牙位为实验B组,对照侧第1、2前磨牙牙位为对照组。3个月后植入种植体,制备种植体周围骨缺损。实验A组骨缺损区植入OAM/PRP;B组植入OAM;对照组植入磷酸三钙。8、16周分别处死动物2只,进行组织学观察,能谱分析种植体-新骨界面Ca含量。结果8周时,A、B组新骨与种植体形成区段性骨结合,对照组种植体边缘为纤维性界面。各组间种植体-新骨界面Ca含量存在显著性差异。16周时,实验A、B组可见哈佛氏系统,新骨与种植体形成骨整合,对照组为纤维性结合。实验各组Ca含量均显著高于对照组。结论OAM及PRP/OAM能促进种植体周围骨缺损修复。     

紫外线处理微弧氧化种植体的早期成骨研究

目的研究C波段紫外线(ultraviolet C,UVC)处理的微弧氧化(micro-arc oxidation,MAO)纯钛种植体植入兔胫骨后的早期成骨方式。方法实验分2组,MAO组和UVC-MAO组。MAO组将医用纯钛种植体经微弧氧化处理后植入新西兰大白兔胫骨。UVC-MAO组将医用纯钛种植体经过微弧氧化处理后,用15 W UVC灭菌灯对钛种植体照射48 h,经过25.0 kGyγ射线消毒后植入新西兰大白兔胫骨。2周后取出胫骨,用锥形束CT观察种植体表面成骨情况;制作胫骨硬组织切片,并以亚甲基蓝-酸性品红染色,光学显微镜观察两组种植体的成骨方式。结果 MAO组可见靠近种植体骨环底端的为成骨细胞及软组织,无任何骨组织,骨环斜面有从周围成熟骨生长的骨组织及类骨质,但所有组织与种植体表面均有一定距离,而非密切接触材料表面。UVC-MAO组可见种植体骨环底端及骨环斜面表面紧密接触类骨质及成骨细胞,还有已经分化的新生骨组织;所有组织与种植体表面紧密接触,无间隔。结论紫外线处理微弧氧化后的种植体,更有利于成骨细胞粘附于种植体表面,形成新生骨质并紧密贴附于种植体表面,骨环周围成熟骨质同时向种植体生长,有利于种植体早期的接触成骨。     

PRP及PRP/OAM对种植体周围骨缺损修复的实验研究

目的探讨富血小板血浆(PRP)以及PRP复合骨诱导活性材料(PRP/OAM)对种植体周围骨缺损修复的作用。方法选取成年Beagle犬4只,体质量10~13 kg,每只犬左右两侧下颌第四前磨牙牙位随机分为A组和B组,与B组同侧的第一、二前磨牙牙位作为对照组。A组种植体周围骨缺损区植入PRP/OAM,B组植入PRP/磷酸三钙,对照组植入磷酸三钙。采用能谱分析各组种植体-新骨界面Ca~(2+)含量,同时观察各组种植术后8、16周组织学形态。结果 A组和B组种植术后8、16周时种植体部位骨表面Ca~(2+)含量均明显高于对照组(P<0.05);A组种植术后8、16周时种植体部位骨表面Ca~(2+)含量为(26.01±3.28)%和(44.10±7.11)%,明显高于B组(P<0.05);种植术后8周,A组新骨与种植体形成区段性骨结合,B组种植体边缘可有新骨形成,对照组种植体边缘为纤维性界面;种植术后16周,A组和B组新骨与种植体形成骨整合,对照组仅为纤维性结合。结论 PRP及PRP/OAM在种植体周围骨缺损修复中,能有效促进骨缺损修复。     

富血小板血浆与骨诱导活性材料复合物促种植体周骨缺损修复的实验研究

目的:观察富血小板血浆(platelet-rich plasma,PRP)、PRP复合骨诱导活性材料(osteoinduction active material,OAM)对种植体周围骨缺损的修复效果,探讨其作为种植体周围骨缺损修复材料的可行性.方法:Beagle犬4只,拔除双侧下颌第一、二、四前磨牙,3个月后植入种植体,制备种植体周围骨缺损并植入相应骨移植材料.A组植入PRP/ OAM,B组植入PRP,磷酸三钙,对照组植入磷酸三钙.种植术后8、16周各处死2只动物,进行组织学观察,能谱分析种植体-新骨界面Ca2+含量,采用SPSS13.0软件包对数据进行单因素方差分析.结果:8周时,实验A组新骨与种植体形成区段性骨结合;实验B组种植体边缘可见新骨形成,但量较少;对照组种植体边缘为纤维性界面.16周时,实验A组可见哈佛系统,实验A、B组新骨与种植体形成骨整合;对照组为纤维性结合.能谱分析显示,8、16周时各组间钙含量百分比均存在显著差异.实验A组最高,实验B组其次,对照组最低.结论:PRP及PRP/OAM应用于种植体周围骨缺损中,可以促进骨缺损的修复,并形成理想的种植体-骨结合界面.     

富血小板血浆修复种植体周围骨缺损的实验研究

目的探讨富血小板血浆(platelet-rich plasma,PRP)修复种植体周围骨缺损的能力。方法Beagle犬4只,拔除单侧下颌1、2、4前磨牙作为实验牙位。3个月后植入种植体,其周围制备骨缺损并植入相应骨移植材料:实验组植入PRP/磷酸三钙(tricalcium phosphate,TCP);对照组植入TCP。8、16周分别处死动物2只,进行组织学、扫描电镜观察,观察新骨形成和种植体-新骨界面情况,能谱分析种植体-新骨界面Ca含量。结果8周及16周通过肉眼及组织学观察,实验组修复效果优于对照组,种植体-新骨界面Ca含量均高于对照组,差异有显著性(P<0.05)。结论PRP/TCP作为修复种植体周围骨缺损的骨移植材料具有可行性。     

放疗后颌骨骨内种植的Beagle犬动物模型的建立

目的 评估放疗对颌骨骨内种植的影响,以及不同治疗方法对放疗后颌骨骨内种植体周围组织成骨性能、成骨特点、种植体骨结合情况的影响,建立一种符合放疗后颌骨骨内种植特点的动物模型.方法 以Beagle犬为实验动物,拔除其双侧下颌前磨牙和第一磨牙,1个月后,每只犬右侧下颌骨给予50 Gy剂量放射治疗.左侧为对照.放疗后9个月两侧植入埋入式螺纹种植体各4枚,于种植体植入后8周和12周处死动物,取材制作种植体-骨磨片.结果 4只实验犬均无死亡,饮食、活动正常,种植体无松动.组织病理学观察见:8周时,放疗组种植体周围有少量骨组织形成,部分有纤维组织长入,对照组骨组织形成量较放疗组多,与种植体形成了部分骨结合;12周时,两组种植体周围骨组织较8周时明显增加,都与种植体发生了骨结合,对照组的骨组织量及种植体-骨结合程度都优于放疗组.结论 本研究采用的建模方法,较符合放疗后颌骨骨内种植临床实际情况,为今后放疗后骨内种植体周围骨组织再生的研究奠定了动物实验基础.     

牙种植体即刻种植骨愈合过程的组织学观察

目的：了解即刻种植体的骨愈合过程，验证即刻种植的可行性。方法：在１２只犬下颌前磨牙新鲜拔牙创内立即植入纯钛牙种植体，通过组织学光镜和扫描电镜观察术后２、４、６、８、１２周种植体周围骨缺损修复过程和种植体骨结合形成情况。结果：骨缺损区内血块首先机化，而后沿牙槽窝骨壁向中心方向逐渐骨化形成新骨。小于１ｍｍ骨缺损１２周内可完全修复，种植体骨结合形成；１ｍｍ以上骨缺损则不能完全修复。结论：即刻种植体周围骨缺损的修复和骨结合形成类似于拔牙创的愈合，大于１ｍｍ的骨缺损应争取植骨。     

Effects of Thread Depth in the Neck Area on Peri‐Implant Hard and Soft Tissues: An Animal Study

Background: Implants with deep thread depth have been developed for the purpose of increasing total implant surface area. However, effects of implant thread depth remain controversial. The aim of this study is to examine effects of thread depth on peri‐implant tissues in terms of bone–implant contact (BIC), bone–implant volume (BIV), and hard and soft tissue dimensions using comprehensive analyses, including microcomputed tomography (micro‐CT). Methods: Five beagle dogs received experimental intramandibular implants 3 months after removal of their premolars and first molars (P₂, P₃, P₄, and M₁). Two different types of implants were installed in each animal: deep threaded (DT) and shallow threaded (ST). Resonance frequency testing was performed on the day of implantation as well as 4 and 8 weeks after implantation. Intraoral radiography, micro‐CT, and histomorphometry were used to evaluate peri‐implant tissues 4 and 8 weeks after implantation. Results: There were no significant differences in resonance frequency test results between the two groups. Although radiographic analysis showed no group differences, micro‐CT (P = 0.01) and histomorphometry (P = 0.003) revealed the DT group had significantly lower BIC values than the ST group at 4 weeks. However, by 8 weeks, BIC values of the two groups did not differ significantly. No significant differences in BIV or soft tissue height were observed between the two groups at either time point. Conclusion: DT implants showed no benefits over ST implants when inserted in dog mandibles.     

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。     

Effects of the placement of endosseous implants in vascularized bone grafts on bone union in beagle dogs

Recently, reconstructive surgery with revascularized osteocutaneous flaps has been used to restore function in patients with bone defects caused by surgery for oral cancer. However, few basic studies have addressed problems such as the union of bone segments after osteotomy, the effects of dental implant placement on blood flow, and bone formation at the bone:implant interface in grafted bone. Nine adult beagle dogs were divided into three groups of three dogs each. Each group received osteotomized vascularized tibial grafts, osteotomized tibial grafts with implants (implants placed in contralateral limbs as control), or simple (non-vascularized) tibial grafts. The development of bone around the implants was studied by histological examination, contact micro-radiography (CMR), and fluorescent bone labeling. In the dogs receiving osteotomized vascularized tibial grafts, bone bridging was confirmed at both the medial and distal junctions of the bone segments after 4 weeks. Additional newly formed bone was observed after 8 weeks, and bone union at the surface of the segments was completed after 12 weeks. In contrast, bone formation was clearly delayed in dogs receiving simple (non-vascularized) tibial grafts. Histologically, no difference in bone union was evident between limbs with dental implants in tibial bone and control limbs without implants, suggesting that implant placement does not negatively affect revascularization. Fluorescent bone labeling technique confirmed high vascularity of the vascularized tibial bone grafts but not of the simple (non-vascularized) tibial bone grafts early after the procedure. Our results suggest that osseointegration occurred around dental implants placed at the same time as reconstruction with osteotomized vascularized bone grafts in this animal model.     

牙﹑微型种植体支抗联合支抗牵张成骨治疗齿槽突裂的动物实验研究

目的:建立牙、微型种植体支抗联合支抗牵张成骨治疗齿槽突裂的动物模型,评估其治疗效果。方法:成年杂种犬实验组6只,对照组2只。首先形成齿槽突裂外科模型,2周后手术截骨形成一含牙的骨运送盘,在骨运送盘上植入微型种植体支抗,一周后开始牵引。牵张完成后1,2,3月各处死动物2只,对照组术后1月处死。取标本作大体,放射学,及组织学检查。结果:齿槽突裂隙完全关闭,牵张区为丰富的新骨。结论:牙、微型种植体支抗联合支抗牵张成骨能够很好的关闭犬的齿槽突裂隙。     

Treatment of a commercial, machined surface titanium implant with H2SO4/H2O2 enhances contact osteogenesis

BACKGROUND: It has recently been reported that controlled chemical oxidation of titanium (Ti) with sulfuric acid (H(2)SO(4))/hydrogen peroxide (H(2)O(2)) significantly influences the early stages of in vitro osteogenesis. The aim of this study was to evaluate whether this chemical treatment can also influence in vivo bone formation. MATERIAL AND METHODS: Ti implants (Mk III) were etched with H(2)SO(4)/H(2)O(2) for 4 h at room temperature. Mandibular premolars were extracted in eight dogs and, after 3 months, three treated and three untreated implants were placed in each animal. At 3 and 8 weeks postimplantation, the animals were sacrificed, and the implants with surrounding bone were harvested, fixed with formaldehyde, and processed for embedding in LR White. Sections of bone with the implants were prepared, stained with Stevenel's blue and Alizarin red, and analyzed histomorphometrically for percentage of bone-to-implant contact (BIC), percentage of mineralized bone area between threads (BABT), and percentage of mineralized bone area within the mirror area (BAMA). Data were analyzed statistically using two-way analysis of variance. RESULTS: Treated implants exhibited significantly more (P<0.05) BIC than control, untreated ones both at 3 (68.1% vs. 27.9%) and 8 weeks (73.5% vs. 14.7%) postimplantation. However, there was no difference in the BABT and BAMA. Histological analysis confirmed that, in most cases, new bone in contact with the implant formed in a direction away from it. CONCLUSIONS: These data indicate that a controlled chemical oxidation of Ti implants significantly enhances contact osteogenesis and suggest that this treatment may be beneficial for early loading of implants.     

Molecular analysis of healing at a bone-implant interface

While bone healing occurs around implants, the extent to which this differs from healing at sites without implants remains unknown. We tested the hypothesis that an implant surface may affect the early stages of healing. In a new mouse model, we made cellular and molecular evaluations of healing at bone-implant interfaces vs. empty cortical defects. We assessed healing around Ti-6Al-4V, poly(L-lactide-co-D,L,-lactide), and 303 stainless steel implants with surface characteristics comparable with those of commercial implants. Our qualitative cellular and molecular evaluations showed that osteoblast differentiation and new bone deposition began sooner around the implants, suggesting that the implant surface and microenvironment around implants favored osteogenesis. The general stages of healing in this mouse model resembled those in larger animal models, and supported the use of this new model as a test bed for studying cellular and molecular responses to biomaterial and biomechanical conditions.     

Loaded hydroxylapatite-coated implants and uncoated titanium-threaded implants in distracted dog alveolar ridges

AIMS: The aim of this study was to determine the response of alveolar bone after it was augmented vertically with distraction osteogenesis, implanted with hydroxylapatite (HA)-coated implants and noncoated titanium-threaded implants, and subsequently loaded for 1 year. METHODS: Eight dogs each had 4 implants placed horizontally into an edentulous mandibular quadrant. After integration, a distraction osteogenesis device was fabricated in the laboratory. An osteotomy was made to allow the crest of the alveolar ridge to be distracted vertically. After 10 mm of vertical distraction, the distraction devices were stabilized with light cured resin. After bone fill of the distraction gap was radiographically confirmed in all dogs at 10 weeks, 2 implants were placed into the ridges. Four dogs had threaded titanium implants placed, and 4 dogs had threaded HA-coated implants placed, with 1 implant in the distracted bone and 1 implant in adjacent nondistracted bone, for both groups. After 4 months for implant integration, bridges were fabricated and secured to the implants with screws. Crestal bone levels were evaluated by radiographs through 1 year of function. Animals were killed after 1 year of loading for histologic evaluation. RESULTS: The vertical ridge augmentation averaged 8.8 +/- 1.0 mm after 10 weeks of healing after distraction. Analysis of variance indicated a significantly greater change from baseline for HA-coated implants and for distracted bone sites. Histologic examination showed that bone had formed between the distracted segments creating an augmented ridge. The average thickness of the labial cortex in the distraction gap was significantly thinner than the lingual cortex in distracted bone or the lingual and labial nondistracted cortical bone. The presence of a dental implant did not significantly affect cortical bone thickness. Serial sections showed that implants remained integrated and functional without soft tissue inflammation. CONCLUSION: Dental implants placed into alveolar ridges augmented with the technique of distraction osteogenesis were functional for the length of this study.     

The Influence of Surface Roughness on the Displacement of Osteogenic Bone Particles during Placement of Titanium Screw‐Type Implants

Background: Previously, we demonstrated that bone debris, which is translocated during dental implant placement, has osteogenic potential. Therefore, it was hypothesized that implant surface roughness can influence the amount of translocated bone debris/particles and thereby the osteogenic response. Material and Methods: Small titanium implants were left turned (smooth) or blasted and acid etched. The implants were placed in fresh cadaver bone. After explantation, the implants were incubated in a culture medium containing β‐glycerophosphate and dexamethasone up to 24 days. Subsequently, histology, scanning electron microscopy (SEM), DNA analysis, and calcium (Ca) content measurements were performed. Results: For both types of implant during implant placement, bone particles were translocated because of inherent roughness of the implant. SEM and histology confirmed the presence of a bone‐like tissue on the surface of both types of implants, as also confirmed by DNA and Ca measurements. However, the significantly higher roughness of the etched implants accounted for more bone debris and accordingly elevated osteogenic response. Control samples, which had not been placed into bone, did not show mineralization in the same medium. Conclusion: The present study, for the first time, demonstrated that implant surface roughness can increase the amount of the translocated bone particles and thereby also have a beneficial effect on the osteogenic response of these bone particles. It is hypothesized that these bone fragments behave like miniature auto‐grafts and thereby play a significant role to enhance peri‐implant osteogenesis. Optimization of surface topography should be evaluated to take advantage of this additional effect of surface roughness.     

微型种植体-牙联合支抗牵张成骨在牙槽突裂治疗中的应用

目的：探讨微型种植体-牙联合支抗牵张成骨治疗牙槽突裂的可行性,以及微型种植体对支抗牙的影响。方法：成年杂种犬14只,随机分为A、B、C3组,A、B每组6只,C组2只为对照组。首先形成牙槽突裂外科模型,2周后手术截骨,形成一含牙的骨输送盘。A组采用单纯牙支抗的方法,B组采用微型种植体-牙联合支抗的方法,C组骨切开后原位固定。1周后开始牵引,牵张完成后固定1个月,处死全部动物,取标本作大体观察、组织学检查,应用SPSS10.0软件包对2组数据分别作Fisher准确性检验和t检验。结果：2种方法均能关闭牙槽突裂隙。2组犬的阳性数比较有显著性差异（P〈0.05）。A、B2组支抗牙在骨输送盘中的移动量具有显著性差异（P〈0.01）。结论：微型种植体-牙联合支抗牵张成骨治疗牙槽突裂是可行性的,使用微型种植体,可以减轻支抗牙牙周-牙髓组织的损伤,减少支抗牙的倾斜移位。