KOM一段式种植体即刻种植的动物实验研究

目的：观察KOM一段式种植体即刻种植骨愈合过程,探索即刻种植的可行性。材料与方法：将6只狗分3组分别作实验。每组2只动物行KOM一段式种植体即刻种植愈合过程观察;动物分别于术后1、2、3个月处死2只大体标本观察、X线片、光镜、扫描电镜观察;结果：KOM一段式种植体即刻种植可以达到骨怀愈合。结论：1、KOM一段式种植体的即刻种植是一种临床可行的种植方式。2、即刻中植时种植体与骨组织之间的骨间隙是否充填生物替代材料,除了考虑种植体周围骨间隙的大小,还要考虑种植体的初期稳定性。     

XIVE 种植体即刻植入即刻负重的临床观察

目的:评价XIVE种植体在上颌外伤前牙区即刻种植即刻负重修复的临床效果。方法:对26例前牙区单颗或多颗无法保留的外伤残根拔除后,即刻植入XIVE种植体,并即刻负重修复。种植体扭矩控制在35Ncm左右,初期稳定性良好。平均四到五个月后行永久修复。在植入后1、2、4个月对其进行临床及影像学检查。结果:32枚种植体有2枚种植体2周后出现松动,一个月后脱落,其余30枚均在预期时间内形成良好骨性愈合,最终完成修复。结论:上颌前牙区单颗或多颗牙外伤,残根无法保留者,行即刻种植即刻负重修复是可行。早期种植修复有利于减缓牙槽骨的吸收,保留软硬组织的形态,缩短疗程。     

XIVE种植体即刻植入即刻负重的临床观察

目的：评价XIVE种植体在上颌外伤前牙区即刻种植即刻负重修复的临床效果。方法：对26例前牙区单颗或多颗无法保留的外伤残根拔除后,即刻植入XIVE种植体,并即刻负重修复。种植体扭矩控制在35Ncm左右,初期稳定性良好。平均四到五个月后行永久修复。在植入后1、2、4个月对其进行临床及影像学检查。结果：32枚种植体有2枚种植体2周后出现松动,一个月后脱落,其余30枚均在预期时间内形成良好骨性愈合,最终完成修复。结论：上颌前牙区单颗或多颗牙外伤,残根无法保留者,行即刻种植即刻负重修复是可行。早期种植修复有利于减缓牙槽骨的吸收,保留软硬组织的形态,缩短疗程。     

种植体稳定系数测定与种植体负重时机选择

目的:通过测量ITI和Osstem-SS种植系统的稳定系数(ISQ),评价这两种种植体的骨结合情况,为临床确定其上部结构修复时机提供依据。方法:93例牙列缺损患者共植入179颗种植体,根据患者种植区骨量情况分为两组,其中A组为种植区骨量良好,不需骨增量手术病例(62例);B组为种植区骨量不足,需进行骨增量手术病例(31例)。A组共植入125颗种植体,其中ITI种植系统64颗,OSSTEM-SS种植系统61颗;B组共植入54颗种植体,其中ITI种植系统28颗,OSSTEM-SS种植系统26颗。术后即刻及第4、6、8、12、16、24周分别测量各时期种植体稳定系数(ISQ),并同期进行临床和影像学检查。结果:A组中ITI种植系统术后8周ISQ值平均(74.17±1.85),进行负重;OSSTEM-SS种植系统术后12周ISQ值平均(72.00±2.59),进行负重。B组中ITI种植系统术后16周ISQ值平均(65.09±3.42),进行负重;OSSTEM-SS种植系统术后24周ISQ值平均(62.09±6.16),进行负重。负重后临床随访3-24个月所有病例均成功,咀嚼功能良好,患者满意。结论:种植体稳定系数(ISQ)能反应种植体骨结合情况,可以协助医生选择种植后合适的冠修复时机。     

前牙美学区实施即刻种植及延期种植对患者唇侧骨量变化的对比研究

目的：研究对比前牙美学区实施即刻种植及延期种植对患者唇侧骨量变化。方法：选择2012 年4 月至2013 年4 月在我院 接受上颌前牙区的单颗种植手术治疗的患者96 例作为研究对象。根据数字法随机分成即刻种植组48 例（48 颗ITI种植体）与延 期种植组48 例（48 颗ITI种植体）。对比两组术后唇侧骨量情况,唇侧骨的改建情况以及术后1 年的PES评分。结果：即刻种植组 术后1 年的唇侧骨高度较术后即刻显著更高,差异有统计学意义（P＜0.05）。即刻种植组与延期种植组术后1 年水平向骨改建的 种植体冠方C 及中段M 较术后即刻显著更低,差异均有统计学意义（均P＜0.05）。即刻种植组在术后1 年的唇侧牙槽嵴的高度 降低水平明显大于延期种植组,且对于水平向骨改建方面,两组种植体中段M的差异具有统计学意义（P＜0.05）。两组在术后1 年的PES 评分上对比,差异无统计学意义（P＞ 0.05）。结论：即刻种植并未能阻止患者牙槽嵴生理吸收,但种植的美学效果亦较 好。临床运用时应加以关注,掌握好适应证,从而获得最佳疗效。值得重视。     

糖尿病对大鼠骨折愈合影响的实验研究

目的:观察糖尿病大鼠的骨折愈合过程,探讨糖尿病影响大鼠骨折愈合的可能的机制,为临床实践提供理论依据。方法:雄性Wister大鼠140只,随机分成二组,每组70只,A组为糖尿病骨折组;B组为非糖尿病骨折组。建立糖尿病动物模型后,无菌条件下在各组大鼠胫骨中点用手术方法制成骨折模型。术后1周、2周、4周、6周、8周各时间点进行X线检查,观察骨折愈合情况。术后1周、2周、3周、4周、6周、8周分别用ELISA法检测血清中IGF-1含量。分别在1、2、4、6、8周各时间点观察5只大鼠骨痂生长情况并取骨折断端组织行HE染色光镜观察。术后4周、6周、8周每组处死10只大鼠留取双侧胫骨标本,冷冻保存后集中进行生物力学检测。结果:1、大体标本观察结果:各时间点A组骨痂生长减缓延迟。2、X线结果:A组骨折愈合质量在各时间点均明显低于B组。3、生物力学测定结果:4周、6周、8周个时间点A组骨折处骨痂的机械强度均明显低于B组。4、组织学染色显示:术后各时间点1、2、4、6、8周A组与B组相比骨折处局部骨痂成熟延迟并且软骨细胞肥大。5、血清IGF-1含量测定:A组大鼠血清中IGF-1含量低于B组,且高峰延迟1周。结论:1.患有糖尿病后大鼠骨折愈合质量差,比较容易出现愈合延迟甚至不愈合;2.患有糖尿病的大鼠骨折后血清中的IGF-1表达明显低于对照组,且高峰推迟1周。     

利用共振频率分析牙种植体骨愈合期稳定性变化 与早期边缘骨吸收的关系

目的:利用共振频率测量仪(Osstell)连续监测骨愈合期种植体稳定性变化与早期边缘骨吸收的关系。方法:本研究于2010-2011年期间根据纳入及排除标准连续纳入32名成年男性患者作为实验对象共植入45枚Strauman种植体,每名患者选择一颗(4.8mm×10mm)种植体,共计32颗种植体,种植区位于下颌后牙(骨质均为Ⅱ或Ⅲ类骨)。利用共振频率分析仪(Osstell)测量种植体的稳定性,测量时间点为植入时以及术后第1,2,3,4,6,8,12周。另外,影像学分析测量32颗种植体12周时的边缘骨吸收;结果:本实验中所有种植体在12周均实现骨结合,并成功完成种植修复。通过重复性方差分析,见表1,在种植体植入时,初期稳定系数(ISQ)均值为(79.03±6.756)。术后一周,种植体稳定系数(ISQ)均值均呈下降趋势,至术后第2周时达到最低点,与植入时稳定性有统计学差异(P<0.05)。从术后第3周开始种植体稳定系数(ISQ)均值逐渐上升。其中,稳定系数(ISQ)均值在第6周时与第12周无统计学差异,已达到延期稳定期。32颗种植体在第12周的边缘骨吸收均值为(0.86±0.068mm),而在第12周的种植体的稳定系数均值与种植体植入时的稳定系数均值无统计学差异。结论:本实验通过共振频率测量仪(OsstellTM)连续监测,目前的结果认为种植体愈合期边缘骨吸收对种植体愈合期稳定性变化没有影响。     

自体颏部骨移植并种植体修复前牙槽骨缺损的应用研究

目的:评价自体颏部骨移植方法在前牙槽骨缺损植骨及种植的效果。方法:对16例前牙骨缺损的患者进行自体颏部骨移植,分别于植骨12～16周后植入种植体,共植入18枚种植体,术后16～20周完成修复治疗。结果:16例自体骨移植患者中,1例出现术后感染,经局部冲洗换药后后愈合良好,其余患者移植骨均已成活,修复后种植体至今均无脱落,局部外形良好。结论:自体颏部骨移植能有效恢复局部牙槽外形,为前牙美学修复提供良好的基础。     

PRP 与CPC 应用于拔牙后种植位点保存的实验研究

目的:探讨磷酸钙骨水泥(CPC)与富血小板血浆(PRP)混合物应用于拔牙后种植位点保存的可行性。方法:拔除6只犬下颌双侧第三切牙与一侧第一切牙,并于每只犬的3个拔牙窝颊舌侧骨壁分别制造2 mm×2 mm×3 mm缺损,随机在两个牙槽窝内分别植入CPC或CPC与PRP的混合物,第三个不加处置作对照,在术后4、8、12周各处死两只动物,行大体、X线、显微镜观察,比较各组的新骨生成情况。结果:术后4周时CPC/PRP混合物组骨形成早于其他组,8、12周时CPC/PRP混合物组新骨生成明显优于CPC组和对照组。结论:CPC混合PRP可促牙槽窝新骨生成并能保证成骨的高度和颊舌向宽度,从而为后期种植义齿修复提供了必要的条件。     

氧化钛纳米管对即刻种植骨结合影响的实验研究

目的:评价氧化钛纳米管对犬即刻种植骨结合效果的影响。方法:犬拔牙后即刻将光滑表面(对照组)和氧化钛纳米管表面(实验组)种植体植入拔牙窝内,于12周后处死取材,进行显微CT扫描、组织学染色分析以及生物力学检测。结果:扫描电镜显示经过阳极氧化后,钛表面形成了直径为30-80纳米的纳米管状结构;12周后,显微CT扫描结果提示实验组骨体积分数(BV/TV)、骨小梁数目(Tb.N)、骨小梁厚度(Tb.Th)均显著高于对照组,骨小梁间隙(Tb.Sp)显著低于对照组,差异具有统计学意义(P0.05)。术后12周,实验组与对照组骨结合率分别为49.35±11.76%、31.79±13.07%,最大拔出力分别为105.28±27.87N、79.23±20.46N,实验组均显著高于对照组,差异均具有统计学意义(P0.05)。结论:氧化钛纳米管表面有利于促进即刻种植后骨结合的效果。     

A nonlinear homogenized finite element analysis of the primary stability of the bone–implant interface

Stability of an implant is defined by its ability to undergo physiological loading–unloading cycles without showing excessive tissue damage and micromotions at the interface. Distinction is usually made between the immediate primary stability and the long-term, secondary stability resulting from the biological healing process. The aim of this research is to numerically investigate the effect of initial implantation press-fit, bone yielding, densification and friction at the interface on the primary stability of a simple bone–implant system subjected to loading–unloading cycles. In order to achieve this goal, human trabecular bone was modeled as a continuous, elasto-plastic tissue with damage and densification, which material constants depend on bone volume fraction and fabric. Implantation press-fit related damage in the bone was simulated by expanding the drilled hole to the outer contour of the implant. The bone–implant interface was then modeled with unilateral contact with friction. The implant was modeled as a rigid body and was subjected to increasing off-axis loading cycles. This modeling approach is able to capture the experimentally observed primary stability in terms of initial stiffness, ultimate force and progression of damage. In addition, it is able to quantify the micromotions around the implant relevant for bone healing and osseointegration. In conclusion, the computationally efficient modeling approach used in this study provides a realistic structural response of the bone–implant interface and represents a powerful tool to explore implant design, implantation press-fit and the resulting risk of implant failure under physiological loading.     

Osseointegrated alloplastic ear reconstruction with the implant-carrying plate system in children

Osseointegration biotechnology has revolutionized ear prosthetic retention, and the benefits of osseointegrated alloplastic ear reconstruction have been well documented. The aim of this study is to present the authors' clinical experience with the implant-carrying plate system (EPITEC System) in children. For 3.5 years, 14 microtia patients (13 boys and one girl, ages 6 to 16 years) were treated with osseointegrated prosthetic ear reconstruction. A total of 30 titanium implant posts of the system were used; one of the patients had bilateral defects. Implant posts were inserted into a three-dimensional carrier plate, which was fixed by means of screws to the mastoid. All patients were operated on using a one-stage procedure allowing 2 to 3 months for osseointegration, followed by fabrication of the ear prostheses. After follow-up, which varied from 6 to 42 months for each patient, all implants that could be monitored were found to be stable. A total of 21 implant posts remained free from potentially dangerous skin reactions. The soft tissues around five of the implant posts in three patients were hypertrophied. One patient was lost to follow-up. The results suggest that the implant-carrying plate system offers several advantages in children: (1) Location of the implants is independent of the recipient bone available; (2) no apparent submergence is evident; (3) additional anchoring is achieved by newly formed bone growing over and covering the connecting bars of the three-dimensional carrier plate, which is only 1 mm thick; and (4) osseointegration is highly successful. Because of the limited number of cases represented in this article, along with a rather limited observation period, this study is preliminary. For a final evaluation, a longer observation time is needed. Despite this, the authors believe that a one-stage procedure with the system in the mastoid process in children can be recommended.     

Immediate implantation in infected tooth sockets

Although immediate implantation has not been previously recommended in infected sites, it is now becoming a procedure of choice in modern implant dentistry. We report a case of a 65-year-old male patient, who required multiple tooth extractions in the lower jaw and fabrication of a new overdenture in the lower jaw and a complete denture in the upper jaw. Immediate implantation in infected tooth sockets followed extraction. Two NobelReplace Tapered implants (Nobel BioCare, Zürich, Switzerland), one 13 mm long and 4.3 mm wide and the other 13 mm long and 5.0 mm wide, were placed in the position 33 and 43. The site was sutured and a temporary denture was fabricated by adjusting the old denture. After a period of three months the implant site was reopened and healing abutments were placed. Impressions were made using the Impregum Penta Soft (3M ESPE, St. Paul, Minn, USA) polyether material. Ball Abutment Titanium" was used as a patrix attachment and a matrix was inserted into the denture. Clinical examination and x-ray analysis after six months showed no significant changes of the implants. Bone resorption was within standard values. Although it is still a controversial subject, immediate implantation in infected sites can be a safe and predictable procedure if surgical protocols are followed. However, further research is needed to draw firm conclusions.     

Allogeneic materials in complications associated with pre-implantation restoration of maxillary and mandibular alveolar processes. A four case report

There are numerous types of bone replacement materials used to regenerate atrophic alveolar processes before the elective intraosseous implantation. Properties of these materials differ one from another, therefore the choice of material should be thoroughly analysed as well as its type and texture in regard of intraoral conditions and the objective to be achieved. The study involved reconstruction of atrophic alveolar processes with allogeneic bone following unsuccessful use of synthetic and animal materials. The procedure of bone regeneration was performed with frozen bone block (case 1) and allogeneic bone granulate (cases 2, 3, 4) radiation-sterilised with 35 kGy prepared by the Tissue Bank. In all of the presented cases after 3-month implant reorganisation optimal width of the process was obtained, which allowed implant embedment (case 1) or correct implant submergence in the osseous tissue, when implantation took place at the same time (case 2, 3, 4). Allogeneic bone material both, in the form of a block as well as granulate, seems to be an adequate alternative for other materials used in order to widen the bone of the alveolar process, particularly in difficult, complicated cases, where the first regeneration procedure was not successful.     

Numerical investigation of bone remodelling around immediately loaded dental implants using sika deer (Cervus nippon) antlers as implant bed

This study combines finite element method and animal studies, aiming to investigate tissue remodelling processes around dental implants inserted into sika deer antler and to develop an alternative animal consuming model for studying bone remodelling around implants. Implants were inserted in the antlers and loaded immediately via a self-developed loading device. After 3, 4, 5 and 6 weeks, implants and surrounding tissue were taken out. Specimens were scanned by μCT scanner and finite element models were generated. Immediate loading and osseointegration conditions were simulated at the implant-tissue interface. A vertical force of 10 N was applied on the implant. During the healing time, density and Young’s modulus of antler tissue around the implant increased significantly. For each time point, the values of displacement, stresses and strains in the osseointegration model were lower than those of the immediate loading model. As the healing time increased, the displacement of implants was reduced. The 3-week immediate loading model (9878 ± 1965 μstrain) illustrated the highest strains in the antler tissue. Antler tissue showed similar biomechanical properties as human bone in investigating the bone remodelling around implants, therefore the use of sika deer antler model is a promising alternative in implant biomechanical studies.     

Effect of guided bone regeneration on bone quality surrounding dental implants

Bone quality as well as its quantity at the implant interface is responsible for determining stability of the implant system. The objective of this study is to examine the nanoindentation based elastic modulus (E) at different bone regions adjacent to titanium dental implants with guided bone regeneration (GBR) treated with DBM and BMP-2 during different post-implantation periods. Six adult male beagle dogs were used to create circumferential defects with buccal bone removal at each implantation site of mandibles. The implant systems were randomly assigned to only GBR (control), GBR with demineralized bone matrix (DBM), and GBR with DBM + recombinant human bone morphogenetic protein-2 (rhBMP-2) (BMP) groups. Three animals were sacrificed at each 4 and 8 weeks of post-implantation healing periods. Following buccolingual dissection, the E values were assessed at the defects (Defect), interfacial bone tissue adjacent to the implant (Interface), and pre-existing bone tissue away from the implant (Pre-existing). The E values of BMP group had significantly higher than control and DBM groups for interface and defect regions at 4 weeks of post-implantation period and for the defect region at 8 weeks (p < 0.043). DBM group had higher E values than control group only for the defect region at 4 weeks (p < 0.001). The current results indicate that treatment of rhBMP-2 with GBR accelerates bone tissue mineralization for longer healing period because the GBR likely facilitates a microenvironment to provide more metabolites with open space of the defect region surrounding the implant.     

Implementation of contact definitions calculated by FEA to describe the healing process of basal implants

Aims: Bone structure around basal implants shows a dual healing mode: direct contact areas manifest primary osteonal remodeling, in the void osteotomy-induced spaces, the repair begins with woven bone formation. This woven bone is later converted into osteonal bone. The purpose of this study was to develop a model to accurately represent the interface between bone and basal implant throughout the healing process. The model was applied to the biological scenario of changing load distribution in a basal implant system over time. Methods: Computations were made through finite element analysis using multiple models with changing boneimplant contact definitions which reflected the dynamic nature of the interface throughout the bony healing process. Five stages of bony healing were calculated taking into account the changes in mineral content of bone in the vicinity of the load transmitting implant surfaces. Results: As the bony integration of basal implants proceeds during healing, peak stresses within the metal structure shift geographically. While bony repair may still weaken osteonal bone, woven bone has already matured. This leads to changes in the load distribution between and within the direct contact areas, and bone areas which make later contact with implant. Conclusions: This study shows that basal implants undergo an intrinsic shift of maximum stress regions during osseointegration. Fatigue testing methods in the case of basal implants must therefore take into account this gradual shift from early healing phase until full osseointegration is achieved.     

Angiogenesis after sintered bone implantation in rat parietal bone

We studied the effect of bone substitutes on revascularization and the restart of blood supply after sintered bone implantation in comparison with synthetic hydroxyapatite implantation and fresh autogenous bone transplantation (control) in rat parietal bones. Methods for the study included the microvascular corrosion cast method and immunohistochemical techniques were also used. The revascularization of the control group was the same as that for usual wound healing in the observations of the microvascular corrosion casts. The sintered bone implantation group was quite similar to that of the control group. In the synthetic hydroxyapatite group, immature newly-formed blood vessels existed even on the 21st day after implantation and the physiological process of angiogenesis was interrupted. Immunohistochemically, vascular endothelial growth factor (VEGF), which activates angiogenesis, appeared at the early stages of both the control group and the sintered bone implantation group. VEGF reduced parallel with the appearance of the transforming growth factor factor-beta-1 (TGF-beta-1), which obstructs angiogenesis, and the angiogenesis passed gradually into the mature stage. In the hydroxyapatite implantation group, TGF-beta-1 appeared at the early stage of the implants. The appearance of VEGF lagged and it existed around the pores of hydroxyapatite even on the 21st day of the implantation. Proliferation and wandering of endothelial cells continued without any maturing of the vessels. These findings suggest that the structure and the components of the implant material affect angiogenesis after implantation as well as new bone formation.     

The biologic behavior of hydroxyapatite implanted into the maxillofacial skeleton

Eleven patients who previously had undergone elective facial osteotomy and in whom blocks of porous hydroxyapatite were implanted into osteotomy gaps later consented to open biopsy of the implant material. A total of 24 biopsies were harvested at a mean time of 10.2 months following implantation. Gross anatomic findings were recorded at the time of biopsy. Specimens were harvested from the zygomatic buttress of the maxilla (12), the piriform buttress of the maxilla (4), the maxillary interdental premolar region (2), and the anterior mandible (6). Histologic sections were examined undecalcified using a modified trichrome stain. Eight of the 11 patients were followed radiographically for a minimum of 24 months. In the absence of infection, there was rapid fibrovascular ingrowth and, provided there was contact with host bone, bone ingrowth. This was observed in 21 of 24 biopsy specimens. The extent of bone ingrowth, as judged qualitatively, was highly variable and did not correlate with the time interval from implantation, anatomic site, or surface area of bone-implant interface. A healing process involving an osteoid phase of bone maturation and suggestive of continued net bone production was consistently found. The gross anatomic, radiographic, and histologic findings are discussed and provide further insight into the biologic behavior of porous block hydroxyapatite implanted into the maxillofacial skeleton.