平台迁移与种植体颈部骨吸收

二段式种植体完成二期手术或功能修复后,种植体颈部骨嵴常常出现吸收现象,这种现象曾经被认为是正常的生理过程。近年来,有报道将窄径基台用在宽径种植体上,发现这种平台迁移成功控制种植体功能修复后颈部骨嵴高度,认为平台迁移是保护种植体颈部骨嵴水平高度的重要原因之一。本文就平台迁移与种植体颈部骨吸收的关系作一综述。     

下颌后牙区不同骨质内种植体即刻负载的三维有限元分析

目的 采用三维有限元分析探讨种植体在下颌后牙区不同骨质条件下即刻负载的应力分布,以期为即刻负载的应用选择提供参考.方法 建立下颌后牙区654-|种植体及上部牙冠和牙槽骨的即刻负载模型,根据骨皮质和骨松质比例构成不同分为B1(颌骨完全由均质的骨皮质构成)、B2(3 mm厚骨皮质包绕致密骨松质)、B3(1.5 mm厚骨皮质包绕致密骨松质)、B4(1.5 mm厚骨皮质包绕疏松骨松质)4种骨质条件,模拟颊舌向45°、100 N的力在修复体中心集中加载,分析各种植体在不同骨质内的von Mises应力分布.结果 颊舌向加载后von Mises应力主要集中于种植体颈部舌侧骨皮质,由B1至B4种植体4-|颈周骨内应力平均值[分别为(13.17±9.32)、(12.95±9.14)、(15.00±9.44)、(16.81±10.74)N]和种植体5-|颈周骨内应力平均值[分别为(15.51±10.32)、(14.73±8.96)、(16.79±8.40)、(18.34±8.45)N]的改变趋势一致,B3应力明显高于B1、B2,B4应力明显高于B3(P＜0.05).从B1～B4种植体6-|颈周骨内应力平均值[分别为(42.45±25.71)、(41.66±25.29)、(42.70±23.24)、(42.06±23.66)N]随骨质改变不大,但均显著高于相应骨质内4-|、5-|颈周骨内应力(P＜0.05).结论 在本项实验条件下进行即刻负载,种植体周围应力分布不仅受颌骨骨质的影响,种植体的植入位置以及建立合理的咬合同样非常重要.

Abstract：

Objective To assess and compare the peri-implant stress distribution of three posterior implants under immediate loading with 4 different bone qualities using three dimensional (3D) finite element (FE) analysis. Methods A 3D finite element model representing three implants in a portion of mandible at the 654-| region was developed, and three implants received a crown each. Four types of bone qualities (B1,B2, B3 and B4) were designed for the model. Load of 100 N was applied on the occlusal surfaces of the crowns at a 45° angle to the vertical axis of the implants. Results Von Mises stresses in the peri-implant bone of4-| in bone quality from B1 to B4 were ( 13. 17 ± 9. 32), ( 12. 95 ± 9. 14), ( 15. 00 ± 9. 44 ), and(16.81 ±10.74) MPa, and those of 5-| were (15.51 ± 10.32), (14.73 ±8.96), (16.79 ±8.40), and(18. 34 ±8.45) MPa. Stress in bone quality B4 showed the highest value, followed by B3 bone, the loweststress were found in B1 and B2 bone. It was significantly different (P ＜0. 05). However, von Mises stresses in different quality of bone around 6-| [(42.45 ±25.71), (41.66 ±25.29), (42.70 ±23.24), (42.06 ±23.66) MPa] were close to each other, and were as twice or three times as those of 4-| and 5-| , irrespective of different bone qualities. Conclusions The stress distribution around implant under immediate loading was not only affected by different bone qualities, but also by the direction of loading, and the latter may have a greater impact when a severe load delivered.     

自攻型正畸微种植体即刻负载的组织学研究

目的探讨自攻型微螺旋种植体即刻负载持续水平力的可行性及周围骨组织的反应。方法28枚自攻型钛合金微螺旋种植体置于2只犬上下颌骨颊侧的牙根间区。20枚种植体即刻负载约2N持续水平力9周,作为实验组;8枚没有负载的作为对照组。光学和荧光光学显微镜检查不脱钙的种植体周围组织的组织切片。结果所有种植体有良好的初期稳定性。4周时,实验组下颌双尖牙区1枚微型种植体2级松动,下颌磨牙区1枚折断。组织学分析显示,2组微型种植体与周围组织呈骨性结合,实验组骨生长和再生更活跃。结论自攻微螺旋种植体适用于上颌骨及下颌骨骨皮质较薄区作为正畸支抗源。     

口腔内局部因素对于牙槽骨吸收的影响

牙槽骨是高度可塑性组织，人体骨骼中代谢最活跃的部分。牙槽骨具有受压力侧吸收，受牵引力会增生的特性，改建符合Wolff定律。牙槽骨是全身骨骼的一部分．影响骨代谢的全身因素如维生素D缺乏、中年妇女雌激素水平下降、与骨代谢有密切关系的神经肽（如神经肽Y、β-内啡肽，一氧化氮等）、还有影响钙磷代谢的一些疾病均会对牙槽骨产生一定影响。     

种植体直径和长度在Ⅲ类骨质中的优化选择

目的应用Ansys DesignXplorer模块，分析圆柱形种植体直径和长度同时连续变化时对Ⅲ类骨质的颌骨应力的影响，为临床选择和设计种植体提供理论依据。方法建立包含圆柱状种植体的下颌骨Ⅲ类骨质的骨块三维有限元模型，设定种植体直径变化范围为3．0～5．0mm，种植体长度变化范围为6．0～16．0mm，观察直径和长度变化对颌骨Von Mises应力峰值的影响。同时进行颌骨Von Mises应力峰值对变量的敏感度分析。结果随着直径和长度的增加，垂直向加载时，皮、松质骨的EQV应力峰值分别降低了65．3％和76．8％；颊舌向加载时，皮、松质骨的VonMises应力峰值分别降低了76．1％和78．0％；当直径大于3．95mm，同时长度大于10．5mm时，应力峰值响应曲线的切斜率位于-1和0之间；在垂直向加载和颊舌向加载时，长度和直径分别对皮质骨EQV应力峰值的影响更明显。结论种植体直径增加更有利于改善颌骨颊舌向加载下的应力分布，种植体长度的增加更有利于改善颌骨垂直加载下的应力分布。从生物力学角度而言，对于m类骨质在临床上选择种植体时，种植体的直径应不小于3．95mm。种植体的长度应不小于10．5mm。     

用盘钻经牙槽嵴提升上颌窦底手术的临床效果观察

目的 观察并评估应用盘钻行经牙槽嵴上颌窦底提升同期种植体植入术的临床效果.方法 上颌后牙缺失患者37例,种植区剩余牙槽骨高度为3～8 mm,平均(5.61±1.61) mm,应用盘钻行上颌窦底提升,同期植入种植体51枚,评估手术安全性及舒适度.术后3～6个月行上部结构修复,随访3～24 个月,观察种植体稳定性、骨结合及种植体周围骨量变化情况.结果 本组术中提升上颌窦底高度2～8 mm,平均(4.75±1.55) mm;所有病例均未发生上颌窦黏膜穿孔,患者主观感觉良好,痛苦指数为(2.22±0.98).随访期内,所有病例均未出现上颌窦感染等并发症,骨结合良好,种植体及修复体无松动、脱落,留存率100%.种植体根方骨量于术后6个月趋于稳定,术后1年颈部骨吸收(1.20±0.72) mm.结论 应用盘钻行经牙槽嵴上颌窦底提升同期种植体植入术,近期效果满意.

Abstract：

Objective To evaluate the clinical effect of the disk-up sinus reamer (DSR) applied to transcrestal maxillary sinus floor elevation with simultaneous placement of implants. Methods Thirty-seven patients underwent transcrestal maxillary sinus floor elevation with fifty-one implants placed simultaneously using the DSR. The residual bone height(RBH) was 3 to 8 mm, (5.61±1.61) mm on average. The safety of this technique and the pain index during the operation was evaluated. The final prostheses were restored in 3-6 months postoperatively. The follow-up period was 3 to 24 months. The stability and osseointegration of the implants were clinically evaluated, and the endo-sinus bone gain around the implants were measured. Results The elevation height ranged from 2 to 8 mm, with an average of (4.75±1.55) mm. There was no detectable sinus membrane perforation, no serious suffering or uncomfortable subjective sensation in any patients during operation with a pain index of (2.22±0.98). During the follow-up period, no sinus complication was observed. Favorable osseointegration was obtained. There were no implants or prostheses which were loose or lost. The survival rate was 100%. The radiographic results demonstrated that the endo-sinus bone gain tended to reach stabilization after 6 months and the marginal bone loss was(1.20±0.72) mm after 12 months. Conclusions Transcrestal maxillary sinus floor elevation with simultaneous implant placement by DSR is a safe, invasive and handy technique, with higher elevation height,fewer clinical complications and less pain. It shows satisfactory clinical results in short term and a long-term observation is still needed.     

牙种植体嵴顶部设计新理念

随着我国口腔种植的深入开展，不断有新的观点、理念产生，应介绍给同行。 一、牙种植体嵴顶部生物学宽度 由于种植体嵴顶部设计的不同，与生物学宽度相对应的有两种情况（图1）：第一类：埋植式种植系统，以Branemark为代表的这种类型的设计，其结合上皮附着位于基台处，结合上皮下有1．0—2．0mm的结缔组织附着，种植体一基台连接部位于此结缔组织附着层内，在完成修复1年后，牙槽嵴顶端通常要出现骨吸收至于第一个螺纹处。[第一段]     

种植体周围炎导致骨缺损的再结合研究

目的探索种植体周围炎症所致骨缺损的治疗方法,从组织学角度评价治疗后种植体周围骨再生和再结合情况。方法Beagle犬5条,双侧下颌植入标准型Br nemark种植体30颗,建立种植体周围炎骨缺损模型,随机分组进行治疗(1)单纯去除种植体周围炎性肉芽组织;(2)植入不可吸收生物膜;(3)生物膜 骨粉植入;(4)生物膜 生物活性玻璃植入。采用X线和手术直接测量以及荧光标记组织切片和不脱钙硬组织切片,观察种植体周围骨量。采用SPSS12.0软件对数据作方差分析。结果直观测量种植体周围骨量、X线测量骨接触水平、组织学测量矿化沉积率,各组间有显著性差异,P<0.05。骨粉植入组,种植体周围能形成较多的新生骨。结论炎症导致的种植体周围骨缺损,可通过治疗手段达到缺损骨的再生。     

骨结合种植技术在口腔正畸中的应用

骨结合种植支抗技术是将种植体手术植入颌骨中产生骨结合而加强正畸支抗的技术。本文就其稳定性、可行性研究、临床应用和常用的种植部位、类型及目前尚存的不足之处作一综述。     

外置式下颌骨牵张器的研制及实验研究

目的：设计研制一种用于下颌骨的新型种植型骨牵张器。方法：采用国际标准的钛合金材料按照生物力学原理设计机械加工制成，植入山羊的下颌骨完成牵张实验。结果：山羊的下颌骨成功延长15mm，牵张器稳定性良好。结论：该牵张器结构轻巧、操作简便，克服了以往牵张器的不足，具有较高的临床应用价值。