高植入扭力对微型种植体-骨界面愈合的组织学影响

目的:探讨高植入扭力对种植体-骨界面组织愈合的影响。方法:将36枚微型种植体以(14±1)Ncm及(11±1)Ncm的扭力植入4只Beagle犬的下颌牙槽骨,观察7 d及28 d的组织学、组织形态测量学及扫描电镜变化。结果:14 Ncm组植入后7 d界面密骨质有重度微损伤,28 d骨界面仍有许多碎骨屑。而11 Ncm组7 d骨质轻度微损伤,28 d骨愈合良好。2组种植体-骨结合率(BIC)无显著差异(P0.05),7 d时,2组种植体-骨密度(BD)值差异无统计学意义(P0.05),但28 d时,11 Ncm组BD值明显高于14 Ncm组(P0.05)。结论:适度扭力植入种植体的骨界面损伤小、愈合快,而过高植入扭力可造成骨界面严重微损伤,影响骨组织愈合。     

微型种植体支抗

微型种植体支抗系统用作正畸支抗,植入部位广泛,操作简单,患者易于接受,优势明显,但缺点也不容忽视。目前不同外形,不同型号的微型种植体相继出现,本文对其作一综述。     

正畸微型种植体支抗的三维导向植入研究

目的在三维牙颌数据基础上,设计制作引导模板,实现微型种植体支抗的准确植入。方法对需要植入微型种植体支抗的患者进行CT扫描和三维数据重建,在三维数据基础上设计种植体支抗的位置。根据种植体位置,设计可配合的引导隧道,并采用牙冠唇、腭面数据设计定位的翼板;数据利用快速成型技术,制作成实体树脂模板,并引导微型种植体的植入;术后通过CT扫描和三维数据重建观察种植效果。结果完成微支抗种植体引导模板的设计,实体模板对种植体植入的引导稳定,种植体能够准确植入设计位置。结论通过三维导向植入可以使微型种植体支抗达到最佳植入部位,从而有效降低种植体支抗的失败率。     

微小种植体的植入方法及一般植入部位

通过对微小种植体植入时的术前准备、手术操作、术中应注意问题、术后处理及医嘱的论述,介绍微小种植体植入的整个过程.同时,通过对植入部位的确定原则,及8 个微小种植体常见植入部位的介绍,为正畸医生在临床正确使用微小种植体提供一定的参考.     

微型支抗种植体的临床效果观察

目的初步探讨微型支抗种植体周围组织炎症的发病率及相关因素,为今后种植体的设计及临床维护工作提供参考。方法观察分析128枚微型支抗种植体的临床使用情况,定期监测菌斑指数(PLI)、改良龈沟出血指数(mBI)和种植体周探诊深度(PD)等临床指标,并对检测结果进行统计学分析。结果 128枚微螺钉种植体中7枚PD大于或等于4mm,5枚支抗种植体脱落。微螺钉种植体组的PLI、mBI及PD等临床指征均高于对照天然牙,差异均有统计学意义(P<0.05),但种植体组内在不同时期之间检查指数比较差异无统计学意义(P>0.05)。出现黏膜炎的种植体的PLI、PD普遍高于健康种植体,差异有统计学意义(P<0.05),且有随炎症程度的加重而升高的趋势。结论大部分微型支抗种植体周围软组织均出现轻微炎症,在考察支抗种植体颈部软组织健康状况时,应综合采用mBI、PLI与PD这3个临床指征。     

微型正畸支抗种植体即刻挤压植入时骨界面应力分析

目的研究微型正畸支抗种植体即刻植入时骨界面应力大小及分布,为微型支抗种植体即刻加载提供参考。方法将局部下颌骨简化成一个等腰梯形,颌骨骨块长20mm,断面高为30mm,上边宽为10mm,底边宽14mm,皮质骨厚度设定为1.6mm;微型种植体直径设定为1.2mm,长6mm。利用ANSYS9.0软件,建立局部微型种植体-骨的三维有限元模型。下颌骨材料属性设定为线性、正交各向异性,种植体-骨界面定义为完全连接。将断端处、下颌骨局部骨块面及底面的所有节点给予刚性约束。模拟种植体即刻植入时的情况,将骨界面初始位移设定为0、0.05、0.1mm,分析各指定初始位移时骨界面应力大小及分布。结果即刻加载时,0mm初始位移下,种植体骨界面无应力分布;初始位移为0.05mm时,骨界面应力集中在骨皮质内,分布较均匀,衰减幅度很小,近远中方向上的VonMises应力为1648MPa,龈向为1782MPa。初始位移为0.1mm时,近远中方向上的VonMises应力为2012MPa,龈向为2110MPa。结论微型种植体挤压植入时会产生较大的初始应力,即刻加载时,应当考虑这种初始应力。     

下牙槽神经移位术种植体植入

目的:采用下牙槽神经移位术行下颌后牙人工牙种植术。方法:应用经颊侧开窗解剖下牙槽神经血管束同期种植体植入。结果:全部患者均在术后4～9个月完成义齿修复。随访观察1年～5年,平均3年,义齿修复后种植体无松动及脱落,其中2人术后出现下唇麻木,一人3个月后恢复,一人半年后恢复。结论:下牙槽神经移位术适用于下颌后牙区管突距离不足的种植,能满足对修复效果要求高的患者。     

非血管化骨移植种植体以及即刻种植体与软组织结合的实验观察

目的:观察非血管化骨移植种植以及即刻种植体钛金属表面与软组织的结合状况,分析影响二者结合的因素。方法:拔除狗的一侧下颌前磨牙,4周后截除无牙下颌骨段,自体非血管化髂骨移植同时植入纯钛种植体修复下颌骨缺损。对照组动物拔除一侧下颌前磨牙时同期在牙槽窝内植入同样的种植体,缝合牙龈。在术后4、8、16周处死动物,以40g/L中性多聚甲醛灌注固定后,取种植体颈部周围软组织。肉眼观察2组动物种植体与周围软组织结合的紧密程度;HE染色观察结合上皮的组织结构;透射电镜观察结合上皮与种植体结合面细胞超微结构。结果:2组动物在术后4周时,种植体顶端已出龈暴露在口腔内,颈部周围的软组织已达初步封闭;两者的结合还较疏松,软组织较薄,细胞膜的表面突起较少。术后8周时,种植体的颈部软组织已完全封闭,软组织与钛表面结合紧密,即刻种植组动物可见明显的结合上皮;超微结构可见结合上皮有较多的细胞膜突起。术后16周,2组的结果与8周时相似。整个实验过程未发现桥粒结构的形成。结论:在没有明显创伤和感染的情况下,两者均可形成良好的结合;即刻种植体与周围软组织结合较非血管化骨移植种植体更致密。2种种植方法结合上皮与钛表面都不能形成桥粒结构。     

正畸微型种植体支抗稳定性的临床研究

目的：研究微型纯钛种植体承受正畸力后的稳定性。方法：16例安氏Ⅱ类上颌前突的女性成年患者,以植入于上领第二前磨牙与第一磨牙牙根之间牙槽骨的微型种植体作为支抗内收上前牙。种植体植入2周后加力,加力前及加力后9个月分别摄X线头颅定位侧位片,将加力前后的头颅定位侧位片进行重叠,测量微型种植体的移位变化。结果：16例中5例患者的微型种植体伸长并移位（-1．0～1．5mm）。所有微型种植体头部平均向前位移0．4mm,具有统计学意义（P〈0．05）。结论：微型种植体是一种稳定的支抗,但在承受正畸力后并不保持绝对的稳定,某些微型种植体在正畸力作用下会移位。为了防止其移位伤及邻近的重要组织,建议将微型种植体植入在无主要血管和神经通过的区域或植入在牙槽间隔区,必需使种植体与牙根之间保持2mm以上的安全距离。     

种植体和微型种植体支抗在正畸与修复中的联合应用

目的：探讨种植体和微型种植体支抗在正畸与修复中的联合应用的可行性,并观察临床效果。方法：选择24例下颌磨牙缺失时冶牙伸长需要做种植的患者。缺牙区植入ITI种植体,常规种植治疗。同时在对猞伸长的磨牙的近中腭侧和远中颊侧各植入一枚微型种植体,用橡皮链挂在颊、腭侧的种植体上,以压低伸长的对日冶牙齿,定期更换并进行,陆床检查。结果：24例患者中,1枚微型种植钉松动脱落,余23例患者伸长牙平均压低2．4mm,平均压低时间为5．6个月,经种植修复后均获得满意的临床效果。结论：针对下颌磨牙缺失对骀牙伸长的病例,种植体和微型种植体支抗的联合应用,能达到最佳的修复效果。     

即刻负载对正畸用微型种植体的稳定性及周围组织的影响

目的 临床和组织学评价即刻负载连续的,持续的水平力于正畸微种植体的可行性及其对周围组织的影响.方法 32枚钛合金微型种植体放置于两只狗的上下颌骨颊侧的牙根间区,愈合在开放的环境下.研究组包括28枚微型种植体,即刻负载约200克的、连续的水平力持续,9周.4枚没有负载的微型种植体作为对照组.在负载开始及结束时,测量相互受力的微型种植体之间的距离,种植体周边袋.光学和荧光学显微镜检查脱钙和不脱钙的微型种植体周围组织的组织切片.结果 9周负载后,研究组有24枚微型种植体无松动,无X线阴影.研究组移位距离在上颌(0.93±0.32)mm,在下颌(0.66±0.45)mm.对照组微型种植体没有松动、移位、倾斜现象.组织学分析显示,在两组中均可见微型种植体与周围组织的骨性结合,其间没有软组织.骨结合可见于微型种植体在骨皮质区的任何部位.结论 微型种植体是有效的支抗工具,可以即刻负载.但是,由于有微移动,植入位置应该与生物器官有一定的距离.     

Load-related bone modelling at the interface of orthodontic micro-implants

Abstract: The purpose of this study was to determine the interface reaction of two different titanium micro‐implant systems activated with different load regimens. A total of 200 micro‐implants (100 Abso Anchor^® and 100 Dual Top^®) were placed in the mandible of eight Göttinger minipigs. Two implants each were immediately loaded in the opposite direction by various forces (100, 300 or 500 cN) through tension coils. Three different distances between the neck of the implant and the bone rim (1, 2, 3 mm) were used. The loads provided by superelastic tension coils (which are known to develop a virtually constant force) led to a range of tip moments 0–900 cN mm at the neck of implants. Non‐loaded implants were used as a reference. Bone tissue responses were evaluated by histology, histomorphometry and scanning electron microscopy after 22 and 70 days of loading. Implant loosening was present in the groups where the load reached 900 cN mm. No movement of implants through the bone was found in the experimental groups, for any of the applied loads. A direct bone‐to‐implant contact to various extents was observed at differently loaded implants. Ultrastructural analysis confirmed the clinical and histological finding that implants (except when loaded at 900 cN mm) were well osseointegrated after 22 days. An increase in the bone‐to‐implant contact ratio was observed during the experimental period in the coronal part of the implants in most experimental groups. The difference reached a level of statistical significance at 500 cN mm (Abso Anchor^®) and 600 cN mm (Dual Top^®). We conclude that micro‐implants can not only be loaded immediately without impairment of implant stability but many enhance bone formation at the interface when the load‐related biomechanics do not exceed an upper limit of tip moment at the bone rim.     

Success rate of mini- and micro-implants used for orthodontic anchorage: a prospective clinical study

OBJECTIVES: Whereas micro-implants have become a useful alternative as orthodontic anchorage elements in orthodontics, less is known about the clinical effectiveness of micro-implants. The aim of this prospective clinical study was to evaluate the success rate of micro-implants used for orthodontic anchorage. MATERIAL AND METHODS: A total of 133 mini-implants (79 Abso Anchor, 54 Dual Top implants) placed in 49 patients to support orthodontic tooth movements were examined in the study. The majority of the implants were placed in the maxilla (82), followed by the vestibular (42) and lingual (nine) aspect of the mandible. RESULTS: An overall cumulative survival rate of 86.8% (102/133) was found by Kaplan-Meier analysis. The failure rate between Dual Top implants (13%) and Abso Anchor implants (30.4%) differed significantly (P=0.0196; log-rank test). The cumulative failure rate of implants was found to be significantly higher when implants were placed in the lingual aspect of the mandible compared with the other localizations (P=0.0011; log-rank test). Clinical evaluation revealed successful dental movements when implants remained stable during the orthodontic therapy. CONCLUSIONS: The present results confirm the effectiveness of orthodontic micro-implants used as anchorage elements.     

Normal histology and the effect of acute mechanical stress on the esophagus epithelium in the guinea pig

With the aim of investigating histologically the effect of acute mechanical stress on keratinized mucosa of the guinea pig, examination of the esophagus was carried out on 50 adult animals. Twenty-eight served as normal controls, while in 22 animals the esophagus was dilated in vivo 10 min by means of polyethylene tubes of varying diameter before killing the animals. In histological sections from six non-dilated esophagi the length of the epithelio-mesenchymal border (basement membrane) was measured at a distance of 15 and 20 mm from the larynx. No difference was found when measured at the two levels in one and the same animal, whereas there was a significant variation between different animals. Macroscopically the esophageal mucosa showed a complex system of circularly arranged keratin crests, divided into segments. Histologically the configuration of the epithelium-connective tissue union showed a regularly scalloped pattern. The spinous cells were arranged in arcades stretching from one epithelial ridge to the next. The stratum granulosum was distinct with deeply stained keratohyalin granules. The stratum corneum was divided into a narrow heavily stained deeper zone and a loosely structured, lightly stained upper zone. In vivo dilation of esophagi resulted in a uniform flattening of the epithelium without break in continuity of the tissue. The scalloped epithelium-connective tissue boundary was evened out. The length of the basement membrane of the dilated esophagus was found to be considerably greater than in control animals. The investigation demonstrated that lining epithelium is pliable to a great extent and adapted for marked elongation.     

A comparative light-microscopic, electron-microscopic and chemical study of human vaginal and buccal epithelium

The scarcity of sizeable specimens of normal oral mucosa for experimental purposes has hampered research on oral epithelium. Because large specimens of viable human vaginal mucosa are readily available and because vaginal and buccal epithelia are microscopically similar, vaginal mucosa has been used successfully to establish a human cyst model in experimental animals. The ultrastructure and distribution of keratin filaments in these epithelia are also similar, as is their permeability to water and a number of chemical substances. Therefore, if vaginal mucosa could be substituted for buccal mucosa it would expedite research on the epithelium of buccal mucosa. To strengthen further the concept that vaginal epithelium could replace buccal epithelium in certain experimental studies, the thickness of these epithelia, their patterns of surface keratinization, the presence or absence of intercellular lipid lamellae and their lipid contents were now compared. Thirty-three specimens of vaginal mucosa from postmenopausal women and 36 of buccal mucosa were investigated. To compare the thickness of the epithelial layers the number of cell layers in sections of 20 vaginal and 20 buccal mucosal specimens were counted in the three thickest and three thinnest regions of each specimen. Surface keratinization was evaluated on sections stained with the Picro-Mallory method. To demonstrate lipid lamellae two vaginal and two buccal mucosa specimens were examined electron microscopically after normal fixation and postfixation in ruthenium tetroxide. Following solvent extraction of 11 vaginal and 14 buccal epithelia, quantitative lipid analyses were performed using thin-layer chromatography. No statistically significant differences were found between the maximum and minimum number of epithelial cell layers. The patterns of surface keratinization and the distribution and appearance of the lipid lamellae in the intercellular spaces were similar. The lipid composition of the two epithelia corresponded, except for the cholesterol esters and glycosylceramides, which were higher in buccal epithelium. Ceramides for vaginal epithelium and triglycerides for buccal epithelium were not determined. Based on structural similarities, a similar lipid composition and earlier findings, it is concluded that vaginal epithelium can be used as a substitute for buccal epithelium in certain in vitro, and possibly for in vivo, studies.     

Evaluation of the surface damage of dental implants caused by different surgical protocols: an in vitro study

The implant surface must withstand high insertion torque during implant insertion. The aim of this study was to investigate the damage to implant surfaces caused by two different insertion protocols in vitro. Fifteen titanium implants per group were inserted in standardized polyurethane foam models, group 1 according to a non-threaded surgical protocol and group 2 according to a threaded surgical protocol. Before and after insertion, the surfaces were visualized by scanning electron microscopy (SEM) and non-contact laser profilometry. Different surface area parameters were evaluated and maximum torque during insertion was determined. SEM detected topographical changes such as deposition of the test block and smoothening of the surface in the region of the thread crests in both groups. The laser profilometry analysis revealed significant changes in the surface topography of the implants in both groups, but no differences between the groups. Insertion torque was significantly decreased in the threaded group. Both types of surgical intervention resulted in surface damage. Less damage was detected to the thread crests with the use of a thread cutter, and most of the surface was not visibly affected by the surgical protocol at the microscopic level. The surgical protocol seems to have a minor influence on preservation of the implant surface.     

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。     

多层螺旋CT辅助微螺钉种植支抗的应用研究

目的应用微型种植体支抗内收上颌前牙,观察上颌前牙及第一磨牙位置的变化,评价微型种植体作为强支抗的应用效果。方法从临床病例中选择20例双颌前突的患者,矫治设计拔除4颗第一双尖牙,随机选择10例在后牙区植入微螺钉型种植体支抗内收前牙,另10例采用腭杆加口外弓的支抗方法。于治疗前拍摄螺旋CT,了解种植区的解剖情况,于治疗前及关闭拔牙间隙后拍摄X线头颅侧位片,测量前牙内收情况及磨牙支抗的变化。用配对t检验比较治疗前后的差异。结果①微型钛钉种植体在拔牙间隙关闭的过程中保持了稳定,成功率93%。②种植体支抗较非种植体强支抗治疗前、后上中切牙倾角及凸距的改变有显著性统计学意义(P<0.05);两组磨牙位移的差异有统计学意义(P<0.05);下切牙切端位移的差异无统计学意义(P>0.05)。结论初步临床观察结果表明,微型钛钉种植体能作为稳定的骨性正畸支抗,可以实现理想的支抗控制效果。     

The differentiation profile of the epithelium of the human lip

The aim of this study was to analyse the immunohistochemical differentiation profile of the stratified squamous epithelium of the adult human lip. Full-thickness lower lips taken from 31 cadavers were analysed. Sections were stained with haematoxylin and eosin, periodic acid-Schiff (PAS), cytokeratins (CK), loricrin, involucrin, profilaggrin and filaggrin. The stratified squamous epithelium covering the lip could be divided into: (i) appendage-bearing, orthokeratinised epidermis; (ii) orthokeratinised vermilion which had a more prominent rete pattern than the epidermis; (iii) parakeratinised, PAS-positive intermediate zone; and (iv) non- or parakeratinised labial mucosal epithelium. Epithelial thickness increased gradually from the skin to the mucosal aspect. The CK pattern changed across the intermediate zone, with gradual loss of CK 1 and 10 from the skin, and CK 4, 13 and 19 from the mucosal, aspect. CK 5 and 14 were consistently expressed basally, and variably expressed suprabasally. Apart from labelling Merkel cells, CK 8, 18 and 20 were negative. Involucrin, which was present at all sites, was restricted to the stratum granulosum in skin, but extended into the stratum spinosum, and gradually into parabasal keratinocytes, across the vermilion and mucosa. Loricrin, profilaggrin and filaggrin were present in the stratum granulosum of orthokeratinised sites, but expression was abruptly lost at the junction between the vermilion and the intermediate zone. In conclusion, the phenotype of the stratified squamous epithelium covering the lip changes at, or across, the intermediate zone of the adult vermilion. It is possible that changes in the composition of the stratified squamous epithelium affect the colour of the vermilion.