不同受力条件下微螺钉支抗种植体稳定性的动物实验研究

目的:探讨微螺钉支抗种植体在不同受力条件下的稳定性。方法:观察在3 0 0 g力值下,以微型螺钉种植体为支抗,牵拉犬上下颌尖牙;在15 0 g力值下压低上颌前牙;在3 0 0g、40 0 g、60 0 g逐渐加力和60 0g即刻加力情况下,种植体交互牵引。观察尖牙横向位移、前牙压低位移以及微螺钉支抗种植体的相互位移情况。结果:种植体拉尖牙移动、压低前牙有效。在60 0 g力的条件下种植体发生相互位移,并有部分种植体发生松动。结论:微螺钉种植体支抗的稳定性与受力大小有关。     

正畸使用微螺钉种植支抗研究进展

目的:报道正畸微螺钉支抗种植体植入后的有关功能和形态学的变化.方法:收集近8年国内外公开发表(截止08年2月)的有关文献.文献内容包括实验性动物(小猪,beagle狗和猴子)研究和临床试验性研究(接受正畸治疗的牙颌畸形患者),使用直径1.1～2.2mm和微种植螺钉和小型钛板作为正畸临时骨性支抗.分析加力前等候时间、加力大小、稳定情况、副作用、骨整合及失败率情况等.结果:微螺钉支抗种植体在功能和结构上均能满足对支抗的要求;种植体未发现有严重的副作用;加载前等候时间从零到12周不等;加力范围从25g到500g.骨与种植体的整合度从10%到58%,支抗螺钉植入后随着时间的推移骨结合量也随之增加,骨结合量的多少与种植体负载与否没有显著性差异,负载种植体压力侧与张力侧的骨结合量没有显著性差异;微螺钉支抗种植体失败率从0%～19%不等.种植体置入位置、手术方法、种植体加力时机以及负载大小等因素均有可能影响成功率.结论:理想的加载前等候时间和加载力值、种植体植入手术和种植体植入的最适宜位置,仍待日后采用标准化程序进行标准化研究.     

微型种植体支抗稳定性的临床研究

目的：对微螺钉种植体在正畸支抗中的稳定性进行研究。方法：按微螺钉种植体支抗的标准操作规程对50例各类错畸形采用直丝弓矫治技术配合自攻型微螺钉支抗种植体进行矫治,共种植微螺钉135个,微种植钉的负载期为8～12个月,评价各个临床变量对微螺钉种植体稳定性的影响。结果：微型种植钉的成功率为95.6%,下颌平面角的高低、微螺钉直径、患者口腔卫生状况,对微种植钉的稳定性影响明显,微种植钉的定位及加力情况对微种植钉的稳定性无显著影响。结论：选择较粗的螺钉,对下颌平面角较高的患者采取谨慎设计,严格手术操作,维持好的口腔卫生是微螺钉支抗种植体种植成功及能否稳定行使功能的关键。     

不同加载条件下的微螺钉支抗种植体骨界面的组织学观察

目的:研究微螺钉支抗种植体在不同加载力值、加载时机与颌骨的结合程度及种植体的稳定性.方法:在3只杂种犬的上、下颌骨分别植入36枚钛合金微螺钉种植体,根据植入颌骨的部位(左、右侧)分为即刻加力组和延期加力组.植入犬左侧颌骨内的延期加力组种植体暂时不加力,4周后与植入犬右侧颌骨内的即刻加力组同时加力.每侧近中种植体不加力,远中2枚种植体相互加力,上颌骨加载1.96N力,下颌骨加载3.92N力.第13周处死动物.标本常规脱钙,行BMP-2免疫组化染色,利用图像分析方法测定骨界面区BMP-2的平均灰度值,分析种植体与骨组织的结合情况.采用SPSS10.0软件包对数据进行t检验和方差分析.结果:即刻加力组(1.96N力、3.92N力)、延期加力组(1.96N力、3.92N力)与非加力组的种植体骨界面BMP-2平均灰度值均有显著性差异(P<0.05),即刻加力组与延期加力组之间平均灰度值无显著性差异(P>0.05).结论:即刻加载、延期加载正畸矫治力均有助于提高微螺钉支抗种植体与周围骨组织骨性结合的能力.正畸力的加载时机对微螺钉种植体稳定性的影响较小.     

自攻型微螺钉种植体支抗的临床应用研究

目的 研究自攻型微螺钉种植体作为磨牙强支抗的临床应用效果.方法 在30例采用自攻型微螺钉种植体作为磨牙支抗的临床病例中,选择6例已经结束治疗的患者进行分析.6例患者均为骨性Ⅱ类上颌前突患者,拔除上颌双侧第一前磨牙后采用上颌强支抗进行矫治.选择自攻型微螺钉种植体作为上颌支抗,以内收上颌前牙、关闭拔牙间隙.种植体植入部位为上颌第二前磨牙与第一磨牙牙根间的颊侧牙槽间隔,加力值为每侧1.47～1.96 N.对患者拔牙间隙关闭前后的头颅定位侧位片进行分析,测量前牙内收情况和磨牙支抗的变化.结果 6例患者共植入12枚微螺钉种植体,矫治后其上颌前突症状均得到明显改善,上颌切牙切缘平均内收6.06 mm,支抗磨牙平均前移0.44 mm,均获得了磨牙强支抗效果.治疗中,种植体保持稳定,种植体周围的软组织健康.结论 自攻型微螺钉种植体支抗是一种简便、有效的支抗形式,可以满足正畸临床治疗的需要.     

自攻型微螺钉种植体支抗周围骨组织中MMP-9表达变化的研究

目的：通过检测种植体支抗周围骨组织MMP-9含量,从分子水平来探讨种植体支抗周围骨改建情况。方法：选用成年雄性杂种狗4只,随机分为1、2、4、8周组。在每只狗上颌颊侧磨牙区靠近膜龈联合处植入微螺钉,每侧2枚,每组4枚。即刻用镍钛拉簧（1.96N）对拉同侧种植体。在相应的分组时间处死动物,进行免疫组化染色。采用spss17.0软件包进行Χ2检验,检验水准a=0.05。结果：HE染色显示即刻加载自攻型微螺钉种植体支抗颈部周围骨组织改建在即刻加载8周内以纤维改建为主;基质金属蛋白酶9（MMP-9）含量在即刻加力8周内表达有差异,加力2周时表达含量最高。结论：即刻加载微型种植体支抗周围颈部骨组织改建在加力8周内以胶原纤维改建为主;MMP-9与微螺钉种植体支抗骨组织周围骨改建密切相关。     

微螺钉种植体支抗的并发症分析

目的 研究自攻型微螺钉正畸支抗的稳定性及其并发症。方法 本院门诊2007年1月—2009年6月,经严格适应证和禁忌证选择的55例应用微螺钉的正畸患者,共植入107枚自攻型微螺钉,手术后立即加力负载。观察微螺钉种植体支抗并发症的表现,发生并发症的微螺钉的植入部位,计算微螺钉相关并发症的发生率。结果 86枚微螺钉完成正畸支抗,13枚松动,7枚发生周围炎。应用过氧化氢和含抗生素的生理盐水局部冲洗以消除炎症。1枚于手术5d后发生局部植入后出血。结论 微螺钉种植体是正畸的有效支抗,同时应重视并防治其并发症的发生。     

助攻型和自攻型支抗种植体稳定性的比较研究

目的：研究支抗种植体在正畸治疗中的稳定性。方法：选取52例成年双颌前突患者,支抗种植体植人第二前磨牙和第一磨牙之间。每个患者分上下左右对称植入自攻型和助攻型种植体各2颗,总共4颗。共计208颗微螺钉支抗种植体,植入2周后加力,常规矫治,矫治中松动无法行使加力功能的支抗种植体给予拔除后重新植入新种植体,做好记录。矫治结束后分别统计自攻型和助攻型支抗种植体的脱落数和部位。结果：自攻型脱落5颗,助攻型脱落8颗,发生在上颌10颗,下颌3颗。结论：自攻型和助攻型支抗种植体脱落率无显著性差异,支抗种植体上颌比下颌易于脱落。     

三维有限元法在微螺钉种植体研究中的应用

微螺钉种植体是一种发展前景良好的骨性支抗,生物力学是微螺钉种植体支抗研究的重要领域。三维有限元分析法在口腔生物力学研究领域中有着无可比拟的优越性,本文特对该方法在微螺钉种植体支抗生物力学研究中的应用作一综述。     

种植体支抗的临床应用初步研究

目的 :以骨融性种植体和微螺钉种植体作支抗来移动牙齿 ,观察其支抗效果。材料和方法 :患者 2 4例 ,5例为骨融性种植体支抗患者 ,另 19例为微型螺钉种植体支抗患者。 5例骨融性种植体支抗患者中男l例、女 4例 ,最大 4 1岁 ,最小 2 0岁 ,平均 32岁。患者缺失后牙 1～ 7颗 ,种植体l～ 7个。另外 19例微型螺钉种植体患者中男 4例、女 15例 ,最大 4 0岁 ,最小 13岁 ,平均 2 2 .8岁。其中 2例患者采用种植体支抗压低伸长的磨牙 ,1例用作垂直牵引支抗 ,2例采用微螺钉做支抗来推磨牙向远中 ,其余 14例作为拔牙后关闭间隙的支抗。结果 :1)骨融性种植可以用作正畸支抗 ,能承受前后向、左右向、垂直向 3个方向的矫治力。 2 )通过X光片研究显示 ,5例骨融性种植体患者在正畸加力过程中和矫治后 ,种植体与牙槽骨融 (结 )合良好 ,没有不良的影响。临床检查也未发现松动的现象。 3) 5例骨融性种植患者均在正畸完成后利用原种植体进行了修复治疗。因此骨融性种植体既可以作为正畸矫治的支抗 ,又能作为永久修复的桥桩 ,是成年缺失牙患者最佳的选择。 4 )微螺钉种植体作为正畸支抗体效果良好 ,可用于各种年龄的患者 ,在压低磨牙、推磨牙向远中、作为支抗体内收前牙、关闭间隙方面具有明显的优势。微螺钉种植体有望广泛应用     

Effects of lateral cortical anchorage on the primary stability of implants subjected to controlled loads: an in vitro study

Our aim was to evaluate the effects of lateral cortical anchorage on the primary stability of implants subjected to immediate loading. Implants were placed into bovine bones with monocortical anchorage (implant placed through the cortical bone of the crest) and bicortical anchorage (the crest cortical bone plus one cortical bone on the lateral side). Loads of 25N and 50N were applied to the implants in different cycles. The implant stability quotient (ISQ) was measured before and after the cyclic loadings. Under 25N load there was no difference in ISQ between 1800 cyclic loading and preloading, but the values decreased significantly after 3600 cyclic loading in both groups (p<0.05). Under a 50N load the ISQ value after 1800 and 3600 cyclic loading decreased in the monocortical group (p<0.05), but there was no difference between 1800 cyclic loading and preloading in the bicortical group, and the ISQ in the bicortical group was higher than in the monocortical group after 1800 cyclic loading (p<0.05). Our results suggest that the stability of implants with bicortical anchorage decreased more slowly under higher loads.     

Bone‐to‐implant contact of orthodontic horizontal implants in humans subjected to loading

Implant‐based anchorage in orthodontics is increasingly obtaining significance. In this study, implants were temporarily inserted into the mid‐palatal and the mandibular retromolar areas in humans for orthodontic anchorage. Histological analysis of the implant‐bone interface was performed following the retrieval of implants which were subjected to prolonged oblique orthodontic loading. The results of the histomorphometric evaluation indicated that all the implants serving for orthodontic anchorage were well integrated into the bone despite the prolonged application of the orthodontic loading. Hence, it may be concluded that small‐size, one‐part transmucosal implants with a self-tapping thread and an SLA surface seemed to provide adequate anchorage for orthodontic therapy. Furthermore, the successful integration and the subsequent oblique loading of these orthodontic implants provide evidence that continuous forces in the order of magnitude of 2–6 N are compatible with the maintenance of osseointegration.     

Direct versus indirect loading of orthodontic miniscrew implants—an FEM analysis

Objective

The mesialization of molars in the lower jaw represents a particularly demanding scenario for the quality of orthodontic anchorage. The use of miniscrew implants has proven particularly effective; whereby, these orthodontic implants are either directly loaded (direct anchorage) or employed indirectly to stabilize a dental anchorage block (indirect anchorage). The objective of this study was to analyze the biomechanical differences between direct and indirect anchorage and their effects on the primary stability of the miniscrew implants.

Materials and methods

For this purpose, several computer-aided design/computer-aided manufacturing (CAD-CAM)-models were prepared from the CT data of a 21-year-old patient, and these were combined with virtually constructed models of brackets, arches, and miniscrew implants. Based on this, four finite element method (FEM) models were generated by three-dimensional meshing. Material properties, boundary conditions, and the quality of applied forces (direction and magnitude) were defined. After solving the FEM equations, strain values were recorded at predefined measuring points. The calculations made using the FEM models with direct and indirect anchorage were statistically evaluated.

Results

The loading of the compact bone in the proximity of the miniscrew was clearly greater with direct than it was with indirect anchorage. The more anchor teeth were integrated into the anchoring block with indirect anchorage, the smaller was the peri-implant loading of the bone.

Conclusions

Indirect miniscrew anchorage is a reliable possibility to reduce the peri-implant loading of the bone and to reduce the risk of losing the miniscrew. The more teeth are integrated into the anchoring block, the higher is this protective effect.

Clinical relevance

In clinical situations requiring major orthodontic forces, it is better to choose an indirect anchorage in order to minimize the risk of losing the miniscrew.     

Immediate Loading of Palatal Implants in Stillgrowing Patients: a Prospective, Comparative, Clinical Pilot Study

OBJECTIVE: The objective of this prospective, comparative study was to evaluate the potential of allowing immediate (within 72 hours) loading of palatal implants used for maximum orthodontic anchorage. This is in contrast to the standard protocol calling for a healing period of 12 weeks. MATERIALS AND METHODS: Sixteen patients with a mean age of 14.22+/-1.37 years for whom orthodontic treatment with maximum anchorage was indicated were randomized into two groups. In the SB (immediate loading) group (n=8, mean age 14.15+/-1.2 years), the implants were employed to provide maximum anchorage for a 1.2 x 1.2 mm TPA wire in combination with a molar band within 72 hours of insertion. In the KB (conventional loading) group (n=8, mean age 14.30+/-1.57 years), the implants were not used for maximum anchorage until a 12-week healing period had elapsed. Patients in both groups with implants that were clinically unstable after insertion were excluded from the study. After conclusion of the treatment, the implants were explanted and embedded using the sawing-grinding technique after Donath. Bone-implant contact (KIK) was analyzed using Bioquant Osteo software version 7.10.10. RESULTS: The objective of the orthodontic treatment, to achieve maximum anchorage of the first molars, was achieved in both groups. In the SB group, the mean bone-implant contact was 55.0%+/-21.6. In the KB group, the mean bone-implant contact was 73.1%+/-19.8. With a p-value of 0.1661, the difference between the bone-implant contact values was not statistically significant. CONCLUSION: The results of our clinical study demonstrate that when implants are clinically stable following insertion, it seems that a 12-week healing phase during which the implants are not loaded leads to a non-statistically significant improvement in osseointegration.     

The Anchorage Quality of Mini-implants towards Translatory and Extrusive Forces

AIM: The objective of the present experimental animal study was to investigate the stability of mini-implants (submersion depth 4 mm, ? 3.3 mm) for orthodontic anchorage. Additionally the histomorphologic effects of orthodontic loading were to be analyzed, especially with regard to the activity and location of periimplant osteodynamic reactions. MATERIAL AND METHOD: 16 titanium implants (Orthosystem, Straumann, Waldenburg, Switzerland) were inserted in edentulous areas of the upper and lower jaw of four foxhounds. After a 6-month healing period the fixtures were loaded with extrusive forces (50 cN) in group 1, and with translatory forces (200 cN) in group 2. The osteodynamic changes during the 6-month force application period were documented using stains with calcium affinity (polychrome sequential labeling). The histologic analysis comprised: microsection method, fluorescence microscopy, toluidine blue staining, histomorphometry. RESULTS: All osseointegrated implants were stable throughout the test period. With respect to the apposition lines, the histomorphometric analysis showed more distinct osteodynamic activity in extrusively loaded than in translatorily loaded implants. The activity was more pronounced in the marginal area than in intermediate and apical implant areas. The extent of peri-implant remodeling activity was up to 980 micro m after extrusive loading and 300-700 microm after translatory loading. CONCLUSIONS: The results suggest that even mini-implants are suited to orthodontic anchorage tasks. The question of the required minimum size of orthodontic anchorage implants remains unanswered.     

Short epithetic implants for orthodontic anchorage in the paramedian region of the palate

Orthodontic movement of teeth often requires maximum anchorage, so that additional resistance must be added to teeth to avoid reaction to reciprocal forces. Thus, use of endosseous implants may be a valuable alternative for ensuring stable intraoral anchorage. This study was designed to evaluate the efficacy of short epithetic implants for orthodontic anchorage in the paramedian region of the palate. Twenty-one patients (15 female, 6 male; mean age 25.8+/-9.9 yrs, min 12.7, max. 48.1) were included in this study. Following adequate preoperative planning, an implant system with reduced length, which had already been used for anchorage of epitheses, was placed in the paramedian region avoiding the anterior palatine suture. After a mean period of 4 months with unloaded healing, the implants were subjected to direct or indirect orthodontic loading. Despite varying bone quality and varying vertical bone volume in this region, adequate primary stability was achieved for all of the implants. No implant was lost during the healing period. Three out of the 21 implants placed were considered as failures. Two implants loosened shortly after the start of orthodontic loading. One of these was lost at a later stage due to peri-implant inflammation, while the other one was left in place during the 9-month follow-up period because no inflammation developed and this implant is still indirectly included in the orthodontic treatment. Another implant loosening was observed after 8.5 months following direct loading with 8 N. This implant was also lost due to peri-implant inflammation. The time-related survival probability was 84.8% after 22.9 months. As yet, 4 implants have been removed due to completion of orthodontic treatment. The results of this study indicate that short epithetic implants are suitable to achieve maximum anchorage in the paramedian region of the hard palate in orthodontic treatment.     

The efficacy of two-stage titanium implants as orthodontic anchorage in the preprosthodontic correction of third molars in adults--a report of three cases

Orthodontic movement of teeth is often required to satisfactorily treat a variety of oral rehabilitation problems. Considerable limitations in the clinical application of orthodontic treatment may result from the lack of teeth suitable for anchorage. Three patients with edentulous posterior segments are presented illustrating how implants can be utilized for preprosthodontic correction of impacted third molars rendering them suitable as bridge abutments. The patients have been followed for 8-10 years. Two-stage titanium implants were used as orthodontic anchorage as no dental anchorage was available. Edgewise orthodontic mechanics were used to move the third molars mesially with forces up to 2.5 N (about 250 g). No movement of the implants occurred and they were radiologically and clinically intact at the end of the orthodontic loading and were, therefore, subsequently used as bridge abutments.     

The use of titanium fixtures for intraoral anchorage to facilitate orthodontic tooth movement.

The use of endosseous implants to facilitate orthodontic tooth movement has been periodically reported in the scientific literature for over 40 years. The predictable achievement of rigid bone-implant anchorage was first applied by Br?nemark in 1965. Using the osseointegration method, a prospective study was conducted involving seven adult patients who were treated with titanium implants used as rigid anchorage units. Orthodontic forces were directed off the implants to correct a variety of malocclusions. All 14 implants placed remained stable during the course of treatment with loading forces of 150 to 400 g. No significant complications occurred. Desirable occlusal and facial results were achieved in all cases. The results obtained over a 3-year period of treatment indicate that intraoral rigid anchorage in the absence of observed reciprocal action is possible.     

Immediate function of cortically anchored disk-design implants without bone augmentation in moderately to severely resorbed completely edentulous maxillae.

The completely edentulous maxilla remains a challenge in implant dentistry. Conventional two-stage surgical techniques require two independent invasive surgeries separated by a 5-6-month healing period. In addition, an increased risk of trauma to the implant-bone interface may be caused by a removable transitional complete denture during the interim submerged period, which can compromise implant success or increase crestal bone loss around the implants during initial bone healing. The purpose of this clinical trial was to evaluate the safety and efficacy of immediately loading a fixed implant-supported prosthesis without bone augmentation in moderately to severely resorbed, completely edentulous maxillae. Over a 41-month period, 783 titanium implants (627 laterally inserted disk implants, with or without 156 axially inserted Structure implants) were placed in 72 consecutive patients with completely edentulous maxillae using an immediate loading protocol. After 6 months of function, the fixed restorations were removed and each implant status was verified using radiographs, Periotest evaluations, clinical osseointegration criteria, and torque testing at 20 N-cm. Six months postoperatively, 98% of the implants were radiologically and clinically osseointegrated. Fifty-six gold screws (7%) required retightening after 10 months, but no screw fractures occurred during this study period. The postrestorative follow-up of these patients ranged from 6 to 48 months. As of this report, all of the fixed prostheses remain functional, and no additional implants have been lost. This clinical trial demonstrates that immediate loading of nonsubmerged, laterally inserted disk-design implants may provide adequate primary anchorage and longterm osseointegration in completely edentulous maxillae. The initial multicortical anchorage afforded by the disk-design implant in this study, coupled with biomechanical splinting of the disks (sometimes with more traditional root-form design implants) using a rigid prosthesis, permits a one-stage predictable implant procedure offering rapid restoration of patients to masticatory function.     

Peri-implant bone response to orthodontic loading: Part 1. A histomorphometric study of the effects of implant surface design.

INTRODUCTION: Bone response to orthodontic loading was compared histomorphometrically around 2 different types of osseointegrated implants (porous surfaced and machined threaded) to determine their suitability for orthodontic anchorage. METHODS: Five beagles each received 3 implants of each design in contralateral mandibular locations. After a 6-week initial healing period, abutments were placed, and, 1 week later, the 2 mesial implants on each side were orthodontically loaded for 22 weeks. All implants remained osseointegrated throughout orthodontic loading except for 1 threaded implant that loosened. Light miscroscopy and back-scattered scanning electron microscopy were used to compare responses around the 2 implant designs. RESULTS: Porous-surfaced implants had higher marginal bone levels (P +/- .025) and less relative implant displacement than threaded implants. CONCLUSIONS: Differences in implant surface design can lead to differences in peri-implant bone height and bone-to-implant contact. Porous-surfaced implants might be successful as orthodontic anchorage units.