两种微型种植体支抗植入方法的临床稳定性研究

目的:观察自攻型与助攻型两种方法植入微型种植体支抗的临床稳定性.方法:选择采用微型种植体支抗病例94例共171个种植钉,观察比较自攻型与助攻型植入种植支抗2个月的稳定性.结果:助攻型植入成功率为89.0%,自攻型为97.7%,助攻型成功率低于自攻型(p＜0.05).结论:助攻型微型种植体支抗植入方法临床效果较好.     

微种植体支抗两种不同植入方法稳定性临床应用比较

目的：观察自攻型与助攻型微种植体支抗的临床成功率,比较两种不同植入方法的临床稳定性。方法：选择同一部位（上颌第二前磨牙和第一磨牙颊侧牙槽骨）植入微型种植体支抗病例165例,共324枚种植钉（其中自攻型微种植体33例64枚,助攻型微种植体132例260枚）,分别采用自攻型及助攻型微型种植钉,植入4周后使用正畸矫治力,力值控制在400g以内,比较自攻型与助攻型种植支抗的稳定性。结果：助攻型植入260枚,脱落16枚,植入成功率93.8%,自攻型植入64枚,脱落9枚,成功率85.9%,助攻型成功率高于自攻型（P〈0.05）。结论：助攻型微型种植体支抗植入方法临床成功率较高。     

国产微型钛钉正畸种植支抗即刻负载的稳定性

目的:探讨国产微型钛钉正畸种植支抗即刻负载的稳定性.方法:选择恒牙列正畸病例需要最大支抗者,采用国产自攻型(钛合金)和非自攻型(纯钛)2种微型钛钉作为正畸支抗,前者采用自攻法植入,后者采用非自攻法植入.2种钛钉均为即刻种植、即刻加载.结果:共计种植国产微型钛钉正畸支抗20例52枚,直径(mm)×长度(mm)分别为1.5×12、1.2×7、1.6×11.3种规格.其中成功47枚,失败5枚.在体负载时间3～8个月,平均5.5个月.结论:2种国产微型钛钉用作种植支抗可以满足临床正畸需要.但微型种植钛钉植入后即刻加载约有10.4%的松动失败率,特别是1.2mm×7mm的微型种植钛钉.     

影响自攻型微型种植体支抗稳定性的多因素分析

目的：探讨影响自攻型微型种植体支抗稳定性的多种因素。方法：选取2006年1月～2009年8月需要设计为强支抗而应用了自攻型微型种植体支抗的43例患者,以微型种植体作为支抗,主要用以压低前牙或内收前牙。结果：43例患者植入104颗自攻型微型种植体,其中8颗脱落。结论：重视微型种植体的选择、植入位置与手术操作、微型种植体植入后的加载、植入后的软组织并发症及预防等因素,以提高微型种植体支抗的稳定性。     

自攻型微钛钉种植体增强磨牙支抗的临床应用研究

目的　介绍自攻型微钛钉种植体用于正畸支抗的临床经验 ,评价该型种植体作为强支抗的有效性。方法　在 6 7例采用自攻型微钛钉种植体作为支抗的临床病例中 ,选择 5例II类骨型、上牙弓前突或双牙弓前突患者 ,矫治设计上颌均为减数双侧第一前磨牙 ,支抗设计为磨牙强支抗。内收前牙阶段的治疗应用自攻型微钛钉支抗种植体 ,种植体植入上颌第一恒磨牙与第二前磨牙颊侧根尖部之间的牙槽间隔 ,以每侧 15 0～ 2 0 0g力滑动法内收前牙。比较内收前后头颅X线侧位片 ,测量前牙内收情况和磨牙支抗的变化。结果　 5例牙弓突度均得到明显改善 ,切牙切缘平均内收 6 4mm ,支抗磨牙平均前移 0 3mm ,均获得磨牙强支抗的效果。治疗过程中种植体均保持了稳定 ,种植体周围软组织健康。结论　自攻微型钛钉种植体能作为稳定的骨性正畸支抗 ,代替口外力的使用 ,起到磨牙强支抗的效能。该型种植体具有操作简单灵活 ,可即刻加力 ,不依赖患者合作的优点     

自攻型微种植支抗钉在矫治下颌磨牙舌倾中的应用

目的评价自攻型微种植支抗钉治疗下颌磨牙舌倾的有效性。方法 选择8例下颌磨牙舌倾的正畸患者,应用自攻型微种植支抗钉牵引11颗舌倾的下颌磨牙。分别在微种植支抗钉植入前和取出后拍摄曲面断层片和头颅侧位片,并进行头影测皱及模型测绩分析。结果8例患者所植入的自攻型微种植支抗钉在矫治过程中均保持稳定;舌倾的磨牙均得到有效的直立,矫治后下颌磨牙间宽度增加4．5mm,与矫治前相比下颌磨牙宽度变化差异有统计学意义（P〈0．01）;下颌磨牙高度降低1．2mm,有统计学意义（P〈0．05）;而下颌平面角（MP—SN）及面下高与全面高之比（ANS—Me／N—Me）变化差异无统计学意义（P〉0．05）。结论自攻型微种植支抗钉可有效地直立舌倾的下颌磨牙,避免磨牙伸长,磨牙咬合关系良好。     

口腔正畸学

自攻型微螺钉种植体支抗稳定性的临床研究;支抗种植体在上颌前牵引中的组织学研究;转矩力作用下托槽槽沟变形的实验研究;微型支抗种植钉愈合期骨结合状态的组织学观察;使用正畸菌斑指数评价固定矫治器患者的菌斑分布状况     

微型自攻钛钉种植体支抗压低切牙的初步应用研究

目的介绍微型自攻钛钉种植体用于正畸支抗的临床经验,评价自攻型微型钛钉种植体作为垂直向支抗压低前牙的有效性.材料方法在26例采用微型自攻钛钉种植体作为支抗手段的临床病例中,选择3名患者(年龄20-25岁),均表现为上颌或下颌前部牙齿槽发育过度,采用微型种植体支抗压低前牙.种植体植入上颌中切牙和侧切牙之间的牙槽间隔或下颌侧切牙和尖牙之间的牙槽间隔,每侧以50克力压低前牙.比较压低治疗前后的X线头颅侧位片,测量前牙切缘的压低量和转矩的改变量.结果所有病例治疗后前牙覆(牙合)达到正常,切缘平均压低4.3毫米,转矩平均增加9.8度.治疗过程中所有微型种植体均保持了稳定,种植体周围软组织健康.结论微型自攻钛钉种植体能够作为稳定的骨性正畸支抗,压低前牙,改善覆(牙合)和龈笑.并且具有操作简单灵活,可即刻加力,不依赖患者合作的优势.     

自攻型微钛钉种植体支抗治疗骨性Ⅱ类双牙弓前突错(牙合)

骨性支抗已经被越来越多的用于正畸临床提供支抗控制的手段.应用骨性结合的修复种植体可以实现绝对的支抗控制而不需要依赖患者的合作,但是对于大多数的正畸患者,修复种植体正畸支抗受到植入部位有限、术式复杂、愈合期长等的限制.近来,微型钛钉和微型钛板种植体的应用得到快速发展.本文中,我们介绍一种治疗骨性Ⅱ类双牙弓前突错(牙合)的新的支抗方法,应用自攻型微钛钉支抗内收前牙,改善患者的突面型.     

微型种植钉在口腔正畸学中的应用

微型种植钉作为增强正畸支抗的措施可以获得良好的效果,近年来引起关注。本文介绍了微型种植钉的材质、外形设计特点、适应证、植入方式及植入部位的选择,对上下颌骨骨密度分布,微型种植钉植入的潜在危险因素、并发症,微型种植钉的负载力等问题作了较为详尽的综述。     

Insertion torque of orthodontic miniscrews according to changes in shape, diameter and length

OBJECTIVE: To determine the variation in the insertion torque of orthodontic miniscrews according to the screw length, diameter, and shape. MATERIALS AND METHODS: The maximum insertion torque (MIT) was measured using a torque tester at a constant speed of 3 rotations per minute. Cylindrical and taper type of miniscrews (Biomaterials Korea Inc, Seoul, Korea) with different lengths, diameters, and pitches were tested. RESULTS: The results showed that the insertion torque significantly increased with increasing screw length (P < .01). In particular, there was a significant increase in torque with increasing screw length and diameter (P < .01). An analysis of the serial insertion torque of miniscrews revealed the cylindrical type screw to have much higher insertion torque at the incomplete screw thread, while the taper type screw showed a much higher insertion torque at the final inclination part of the screw thread. The insertion torque was affected by the outer diameter, length, and shape in that order. CONCLUSIONS: An increase in screw diameter can efficiently reinforce the initial stability of the miniscrew, but the proximity of the root at the implanted site should be considered.     

Optimal asymmetric thread for orthodontic microimplants: Laboratory and clinical evaluation

Objectives:To investigate the performance of microimplants incorporating a newly designed asymmetric thread.Materials and Methods:Three microimplants were compared. The control group comprised microimplants with the original v-shaped thread. The two experimental groups (Taper 1.0 and Taper 1.25) comprised prototype microimplants constructed with the new asymmetric thread; the Taper 1.25 specimens had a 1.25-mm-long and sharper tip, while the Taper 1.0 and control groups had a less sharp 1-mm tip. Two specially designed artificial bone blocks mimicking soft (maxillary) and hard (mandibular) bone were used to evaluate the microimplant insertion characteristics and postinsertion lateral stability. The peak insertion torque, insertion time, Periotest value (PTV), and torsional strength were measured. Then the microimplants were evaluated clinically over a 3-month period.Results:Significant differences in peak insertion torque, insertion time, and PTV were observed and favored the experimental groups. Although statistically insignificant, the clinical success rate was also higher in the Taper 1.25 experimental group than in the control group (87.2% vs 75.6%).Conclusions:The better performances of the experimental microimplant, under both laboratory and clinical conditions (although statistically insignificant in the latter), demonstrate the superiority of the new asymmetric thread.     

An easy way to apply orthodontic extraction for impacted lower third molar compressing to the inferior alveolar nerve

PurposeTo study the results of an easy orthodontic extraction method for impacted lower third molar removal which had roots compressing to the inferior alveolar nerve (IAN).Patients and methodsForty patients were divided into two groups according to their desire. Orthodontic traction group (n = 20) had brackets or mini bone screws on the antagonist maxillary molars as anchorage for orthodontic traction from 3 to 10 weeks until the roots’ tip was away from the IAN, the tooth was then removed. Traditional extraction group (n = 20) had the tooth removed immediately by the same surgeon. Post-operative results were compared between the two groups.ResultsAll 20 patients in the orthodontic extraction group had their lower impacted third molar removed easily without lower lip numbness after surgery, while 5 patients in the traditional extraction group had transient IAN injury and went away 1 week later. There were no anchorage teeth and adjacent mandibular second molar loose or displacement.ConclusionApplication of orthodontic brackets or mini bone screws on the antagonist maxillary molars is an easy way for orthodontic extraction of impacted lower third molar with roots’ tip compressed to the IAN. It is an effective way to avoid IAN injury during tooth extraction.     

Torque measurements of the mechanical load capacity of thin bony structures of the visceral cranium

The stability of self-tapping screws of the Luhr (1979)-mini-plate system in thin facial bones was assessed. The maximal possible torque which can be applied to the screws before they strip the thread in the bone was measured. This end point was called the penetration torque. Only the central section of the maxillary sinus wall was unsuitable for anchorage of the screw and plate. The other sections of the osseous middle and lateral parts of the face, of the glabella and of the root of the nose have sufficient strength for bony segments to be anchored using plates.     

Biomechanical properties of small bone screws

To evaluate systematically the biomechanical properties of 13 popular screw designs, ranging from 0.8 to 2.0 mm in diameter. Screws were characterized in terms of external, core, and drill diameter; cutting flute and head design; material; pitch, thread depth; and height of shank (unthreaded portion) and shank with plate. They were tested in standardized bone specimens (2 × 2.5-cm slabs of fresh bovine femur) 1, 2, 3, and 4-mm thick. For each screw-bone thickness combination, 10 trials were conducted to determine push-out force (POF) and another 10 trials to determine insertion (IT) and maximum torque (MT) yielding a total of 1,040 tests. Among the 13 different screws, in 1-mm thick bone, both the lowest (108.5 N) and highest (294.9 N) POF were created by 2-mm screws (P < .001); that with the lowest POF had a long unthreaded shank and pitch, that with highest POF had a short unthreaded shank and pitch. Screws with 0.8- to 1.5-mm diameters showed no differences in POF. The 2-mm screw with the lowest POF also had the lowest MT in 1-mm thick bone compared with the other 2-mm screws (P < .001). In thicker bones (>2 mm), two 2-mm screws showed 30% to 50% lower MT than the other same size screws (P < .001) because their head slots stripped easily. When all screws were considered together for a particular bone thickness, torque was strongly predicted by screw diameter (MT: r = .94, P < .001; IT: r = 0.92, P < .001). Screws with the same diameters varied significantly in IT because of differences in self-tapping cutting flute design. External diameter, unthreaded shank height, head slot, and self-tapping cutting flute design had the greatest impact on screw strength and efficiency in thin cortical bone. Thread depth, core diameter, and metal type did not affect performance significantly. Under these highly standardized in vitro conditions, the ideal 2-mm screw has an unthreaded shank that is as short as possible, and the pitch is about 0.8 mm. Additional aspects of a clinical situation beside holding strength must, however, be considered when choosing a screw.     

正畸辅助水平向牵张成骨治疗牙槽突裂的临床探讨

目的探讨正畸辅助水平向牵张成骨治疗牙槽突裂的临床效果。方法单侧完全性牙槽突裂患者3例,缺损区域远中节段性截骨,保留其血液供应形成一含牙及种植支抗的骨运送盘,牵引骨运送盘向裂隙侧移动,运用牵张成骨的原理修复牙槽骨缺损。结果牙槽骨软硬组织缺损区完全闭合,牵张区新骨形成良好,支抗牙无明显松动及移位,牙髓活力测试正常,种植支抗稳定无松脱。结论采用正畸辅助水平向牵张成骨修复牙槽突裂临床可行。     

Biomechanical characteristics and reinsertion guidelines for retrieved orthodontic miniscrews

Objectives:To analyze morphological variations of retrieved orthodontic miniscrews and to evaluate the mechanical properties that may adversely affect relocation of miniscrews.Materials and Methods:Retrieved miniscrews were classified with scanning electron microscopy according to the degree of morphological deformation of the tip. To evaluate the differences in mechanical characteristics during reinsertion, changes in insertion torque, insertion time and differences in successful insertion load were compared between unused controls and retrieved miniscrews. In addition, surface composition analysis of retrieved miniscrews was performed using energy-dispersive x-ray spectroscopy.Results:Significant tip deformation was evident in the majority (>84.5%) of retrieved miniscrews. Initial conditions such as insertion site or duration of insertion were not associated with the presence of tip deformation. Insertion load for successful bone penetration increased in proportion to the degree of tip deformation; however, serial changes in insertion torque were similar to those of the controls. Deposited debris such as carbon, calcium, and phosphorus was noted on the retrieved miniscrews.Conclusion:Miniscrews retrieved after primary insertion exhibited decreased cutting ability due to deformation of the tip structure, as well as surface contamination.     

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.     

不同微型种植体稳定性比较的动物实验

目的评价自攻型和助攻型正畸微型种植体的稳定性，探讨两种种植体生物力学的差别。方法将自攻型组与助攻型组正畸微型种植体（每组各28枚）种植于两只狗的上下颌骨颊侧根间区，植入时测量最高植入转矩，即刻负载水平力约1．96N，持续9周后取出种植体，测量最高去除转矩。结果上、下颌自攻型组最高植入转矩[分别为（5．6±1．1）N·cm和（8．7±2．3）N·cm]均明显高于助攻型组[分别为（3．5±2．1）N·cm和（7．4±1．1）N·cm]，差异均有统计学意义（P〈0．05）。上、下颌自攻型组最高去除转矩[分别为（-6．5±2．2）N·cm和（-7．1±2．0）N·cm]均高于助攻型组[分别为（-5．7±2．3）N·cm和（-6．1±0．5）N·cm]，差异均无统计学意义（P〉0．05）。自攻型组成功率为92．9％，助攻型组成功率为86．7％。结论自攻型种植体有较高的初期稳定性，适于种植在上颌骨及下颌骨骨皮质较薄的部位。     

Success of miniscrews used as anchorage for orthodontic treatment: analysis of different factors

ObjectivesTo examine factors involved in clinical success of miniscrew implants used for orthodontic anchorage in the upper jaw.Materials and methodsOne hundred and forty-four patients (93 females and 51 males) were fitted with a total of 324 miniscrew implants of two different morphologies (cylindrical and conical), and of different lengths and diameters. The clinical factors examined were screw length, side of insertion, miniscrew shape and diameter, bone quality, skeletal type, and relationship between bone quality and skeletal type and patient age.ResultsThe mean overall success rate of the implants was 91.4%. The length and shape of the miniscrews significantly influenced the success rate, whereas side of insertion (left or right), screw diameter and skeletal type showed no significant effects. Poor (soft) bone quality and good (hard) bone quality are risk factors for miniscrew failure, with the best results obtained when the screws are inserted into bone of medium quality (10-15 Ncm).ConclusionIn the posterior areas of the upper jaw, long, conical miniscrews showed a significantly greater success rate. An insertion torque of 10 Ncm to 15 Ncm is also a significant index of higher success rate.