种植全口义齿的三维有限元分析--基托内金属支架对应力的影响

目的：研究基托内金属支架放置与否对种植全口义齿及其支持组织应力状况的影响。方法：用三维有限元方法，按义齿连接设计的不同，分析比较埋置与不埋置金属支架时种植全口义齿的应力状况。结果：不使用金属支架较使用金属支架，在种植全口固定义齿，骨界面应力增加２７％，基托应力增加３７％，种植体应力增加２１％；在种植全口覆盖义齿，骨界面应力减少１６％，而粘膜应力增加９％，基托应力增加１０％，种植体应力增加１９％。结     

种植全口义齿的三维有限元分析--种植体颈狭部直径对应力的影响

目的：研究种植体颈狭部直径变化对种植全口义齿及其支持组织应力状况的影响。方法：用三维有限元方法,按义齿连接设计的不同,分析比较种植体颈狭部直径为４ｍｍ与２ｍｍ、１ｍｍ时的种植全口义齿应力状况。结果：种植全口固定义齿的种植体颈狭部直径由４ｍｍ减少到１ｍｍ时,种植体中的应力峰值增加了约５７３％;种植全口覆盖义齿的种植体颈狭部直径由４ｍｍ减少２ｍｍ时,种植体中的应力峰值增加了约１０３％;上述直径变化对骨界面、基托、人造牙列及粘膜应力影响不大。结论：改进种植体颈狭部设计、增加其直径,对降低应力峰值、减少其折断发生率有重要意义。     

粘膜厚度和桥架高度对种植全口义齿应力的影响

采用三维有限元方法，探讨粘膜厚度和桥架高度对种植全口义齿应力的影响。结果发现，牙槽粘膜较厚者比较薄者，其种植全口覆盖义齿的基托应力和种植体周围骨界面应力明显增大，而粘膜承担的力有所减少；采用不同的桥架高度设计，没有引起种植全口固定义齿及其支持组织应力状况发生明显变化。     

粘膜厚度和桥架高度对种植全口主齿应力的影响

采用三维有限元方法，探讨粘膜厚度和桥架高度对种植全口义齿应力的影响。结果发现，牙槽粘膜较厚者比较薄者，其种植全口覆盖义齿的基托应力和种植体周围骨界面应力明显增大，而粘膜承担的Ｈｅ力有所减少；采用不同的桥架高度设计，没有引起种植全口固定义齿及其支持组织应力状况发生明显变化。     

种植体支持球帽附着体固位下颌覆盖全口义齿的临床应用

目的评价种植体支持球帽附着体固位下颌覆盖全口义齿的临床应用效果。方法 2006年6月至2010年5月完成种植体支持球帽附着体固位下颌覆盖全口义齿修复15例,每位患者植入2枚种植体,共植入30枚,随访时间1～4年。结果 15例种植体支持球帽附着体固位下颌覆盖全口义齿患者的义齿稳固,咀嚼功能良好。X线片显示随访期间种植体周围未见明显的骨吸收。结论种植体支持球帽附着体固位覆盖义齿临床效果可靠,可作为下颌无牙颌患者首选修复方式。     

下颌球帽附着体覆盖义齿应力研究

目的 分析不同球帽附着体下颌覆盖义齿在不同加载力作用下基托及支持组织所受的应力.方法 采用电阻应变测量法测量下颌球帽附着体覆盖义齿的应力,比较使用不同类型球帽附着体时,下颌覆盖义齿的应力变化.结果 使用金属球帽附着体比使用塑料球帽附着体牙根表面、义齿基托舌侧正中的应变值小,但后牙区 牙槽嵴顶粘膜表面应变值较大.义齿基托...     

种植全口义齿的三维有限元分析——种植体颈狭部直径对应力 …

目的：研究种植体颈狭部直径变化对种植全口义齿及其支持组织应力状况的影响。方法：用三维有限元方法，按义齿连接设计的不同，分析比较种植体颈狭部直径为４ｍｍ与２ｍｍ、１ｍｍ时的种植全口义齿应力状况。结果：种值全口固定义齿的种植体颈狭部直径由４ｍｍ减少到１ｍｍ时，种植体中的应力峰值增加了约５７３％；种植全口覆盖义齿的种植体颈狭部直径由４ｍｍ减少２ｍｍ时，种植体中的应力峰值增加了约１０３％；上述直径变化对骨     

三维有限元法对下颌种植覆盖义齿应力分布的分析

目的：分析种植义齿不同连接方式、即刻载荷式种植义齿、设置缓冲间隙对下颌种植覆盖总义齿应力分布的影响。方法：应用三维有限元法模拟正中开闭口运动中下颌种植覆盖总义齿的受力情况,分析种植义齿不同连接方法、即刻载荷式种植义齿、冲击载荷下缓冲间隙的设置对义齿应力分布的影响。结果：缓冲间隙的设置可以降低种植体内部、种植体软硬组织界面和义齿基托内应力的峰值,最易引起种植体侧方界面骨吸收的压应力峰值降低了约52%。螺丝固定的种植全口固定义齿有助于远期修复效果,即刻载荷式种植义齿初期稳定性尚待研究。结论：螺丝固定的种植全口固定义齿对设置缓冲间隙有利于保护种植体界面软硬组织的健康,防止义齿基托折裂,提高种植义齿的远期成功率。即刻载荷式种植义齿对种植义齿的远期成功率有一定的影响。     

杆卡、球帽和locator附着体种植覆盖义齿的临床对比研究

目的：比较杆卡、球帽、locator附着体种植覆盖义齿修复1．3年后的临床效果。方法：对38名无牙颌患者进行覆盖义齿修复,其中杆卡、球帽、locator附着体种植覆盖义齿分别为11、18和9例。在义齿完成后0．5、1年及每年复查1次。对各组种植体周围粘膜状况和边缘骨吸收（MBL）进行评估,同时检验患者满意度。结果：杆卡、球帽、locator附着体最近一次随访的种植体边缘骨吸收为（1．3±1．0）ram、（1.2±0．8）mm、（1．4±1．0）mm,3种方式修复后MBL比较无统计学意义（P〉0．05）。与原有全口义齿比较,患者满意度均有明显提升（P〈0．05）。三种义齿间种植体周围粘膜状况、患者满意度亦无统计学差异。结论：杆卡、球帽、locator附着体种植覆盖义齿均能明显改善无牙颌患者的咀嚼功能。出于经济学考虑,我们建议选用2枚种植体支持的球帽或locator附着体覆盖义齿,临床上角度偏差较大的种植体可以优先考虑locator附着体覆盖义齿修复。     

天然牙—种植体共同支持式固定义齿的生物力学研究I.垂直集中载荷对种植体、天然牙骨界面应力的影响

目的：通过对天然牙-种植体共同支持式固定义齿受垂直集中载荷时，种植体、天然牙骨界面应力分布情况进行测试，为临床能否使用该方式修复牙列缺损提供生物力学的理论依据。方法：应用电阻应变计电测技术的方法。结果：天然牙-种植体共同支持式固定义齿修复时，在垂直集中载荷下，随着载荷的不断加大，天然牙-种植体与骨组织界面处的应力值不断加大，最大应力出现在种植体、天然牙根颈部区，种植体与稳固的天然牙共同支持式固定修复时，天然牙与骨界面应力分布较均匀。结论：从生物力学的角度来看，在优化临床设计的前提下，天然牙-种植体共同支持式固定义齿是临床可采用的特殊固定义齿，尤其适用于末端游离缺牙的患者。     

不同连接设计种植全口义齿的三维光弹应力分析

目的：研究常规半口义齿、种植杆卡覆盖义齿及种植固定义齿在牙合力作用下其支持组织——牙槽骨及种植体周围的应力分布状况。方法：用三维光弹应力冻结切片法,对在牙合力作用下的应力状况进行应力冻结,并分别在切牙区、尖牙区、前磨牙区、第一磨牙区、第二磨牙区作３ｍｍ厚切片;并在４颗种植体周围作包含种植体的５ｍｍ厚切片,分析其内部的应力分布状况。结果：种植覆盖义齿的种植体周围骨界面,牙槽骨的应力值均比常规义齿及种植固定义齿低,无论是哪种形式的种植义齿,都易发生远中种植体受力过大而松动。结论：种植覆盖义齿具有良好的力学特性;在义齿设计时应采取措施保护远中种植体。     

种植体直径和长度对支持组织应力分布的影响

目的：观察种植体直径、长度变化时由种植体支持的下颌种植覆盖义齿,在牙合力作用下其支持组织——牙槽骨及种植体周围的应力分布状况,探讨种植体长度和直径变化对支持组织应力分布的影响规律。方法：用三维光弹应力冻结切片法,对４种不同长度,３种不同直径的种植体支持的种植覆盖义齿,在牙合力作用下的应力状况进行应力冻结,并在相应部位切片观察,以了解各种状况下其支持组织的应力分布状况。结果：种植体长度变化对种植体周围骨界面及牙槽骨应力的大小有较大的影响,两者呈负相关关系;而在临床常用的几种直径种植体中,直径变化对种植体周围骨界面及牙槽骨应力的影响不大。结论：在种植义齿设计时,应着重考虑种植体长度变化对种植体周围骨界面及牙槽骨应力的影响,种植体直径变化可不作考虑。     

Stress distribution of abutments and base displacement with precision attachment- and telescopic crown-retained removable partial dentures

Five types of removable partial dentures (two attachment dentures, two telescopic dentures and one clasp denture) were designed. The two attachment dentures were retained by the rigid-precision attachments with or without a stabilizing arm, and the two telescope dentures were retained with cone telescope crowns with or without cross-arch stabilization. The stresses acting on abutment teeth and denture bases and the movements of denture bases were investigated, and the influences of denture design were clarified. The stress acting on a terminal abutment tooth retained by a rigid-precision attachment or cone telescopic crown was larger than that acting on a terminal abutment tooth retained by a clasp. The attachment dentures tended to concentrate more stress at the terminal abutment tooth than did the telescopic dentures. The stress of denture base of an attachment denture and a telescopic denture was less than that of a clasp denture. There was no difference between the stresses of attachment and telescopic dentures. The displacement of the denture base tended to be less when the denture was designed with a rigid connection for the retainer and with cross-arch stabilization.     

4 种表面形态种植体对支持组织应力分布的影响

目的：观察４种常见不同形态种植体所支持的下颌覆盖义齿,在牙合力作用下其支持组织——牙槽骨及种植体周围的应力分布状况,从生物力学角度为种植体形态设计提供参考。方法：用三维光弹应力冻结切片法,对光滑圆柱形、光滑圆锥形、螺纹圆柱形、螺纹圆锥形４种不同形态种植体所支持覆盖义齿,在牙合力作用下的应力状况进行应力冻结,并在相应部位进行切片观察,以了解不同情况下其支持组织的应力分布状况。结果：种植体不同的表面形态对支持组织应力分布有较大影响,圆柱形种植体比圆锥形种植体,带螺纹种植体比光滑种植体其牙槽骨及骨界面应力值小。结论：不同表面形态的种植体对种植体骨界面及牙槽骨的应力会产生不同的影响。     

beagle犬埋植型与非埋植型种植义齿骨组织界面改建的组织学观察

目的 :检测埋植型与非埋植型种植体在义齿修复受载后组织学反应的异同。方法 :选用纯系动物beagle犬 8只 ,在其下颌分别植入埋植型与非埋植型种植体 ,采用固定金属全冠行种植义齿修复 ,分不同程期处死动物。采用HE染色对埋植型与非埋植型种植体 -骨界面改建过程进行动态观察 ,比较两者之间的异同。结果 :组织学观察发现 ,种植义齿受载后 ,种植体周围骨组织发生改建。 2周时其界面绝大部分呈直接骨结合 ,但在界面处尤其螺纹顶部出现骨吸收 ,骨组织由纤维组织替代 ;4周时种植体 -骨界面结合良好 ,在界面处出现的纤维组织已逐渐通过改建形成新骨 ;8周时种植体与骨组织直接接触呈骨性界面 ,界面区细胞成分和毛细血管减少 ;12周时所有种植体与骨组织均为骨性结合界面 ,结合程度较高 ,界面区出现典型的哈弗系统。所有埋植型和非埋植型种植体之间无显著差异。结论 :非埋植型种植体与埋植型种植体均获得良好的骨结合。埋植型和非埋植型种植义齿受载后其界面的改建之间无显著差异。     

Pressure distribution of implant-supported removable partial dentures with stress-breaking attachments

PurposeThis in vitro study investigated the pressure distribution of the implant-supported removable partial dentures (RPDs) with the stress-breaking attachments under the occlusal force.MethodsThe experimental model of bilateral missing premolars and molars was modified from a commercial simulation model. Five pressure sensors were embedded near the bilateral first molars, first premolars, and medio-lingual alveolar crest. Two implants were placed near the second molars, and they were connected to the denture base using the following conditions: complete separation between the denture base and implant with cover screws (CRPD), flexible connection with a stress-breaking ball (SBB) attachment, and rigid connection without stress breaking with healing caps (HC). The pressure at five different areas of the soft tissue and the displacement of the RPDs were simultaneously measured, loading up to 50 N. The coefficient of variation (CV) for each connection was calculated from all data of the pressure at five areas to evaluate the pressure distribution.ResultsThe pressure on medio-lingual alveolar crest and molars of the HC was less than SBB and CRPD. In contrast, the pressure on premolars of SBB was greater than for the HC and CRPD. The CV of SBB was less than that of HC and CRPD. Denture displacement of HC and SBB was less than for CRPD.ConclusionsWithin the in vitro limitations, precise denture settlements and pressure distribution under the denture base could be controlled using an SBB attachment. An SBB attachment might be able to protect the implant from harmful force.     

A clinical trial of patient satisfaction and prosthodontic needs with ball and bar attachments for implant-retained complete overdentures: three-year results

STATEMENT OF PROBLEM: Few prospective trials of implant-retained mandibular dentures have evaluated the increase and duration of patient satisfaction, costs of denture maintenance in relation to different methods of attaching overdentures to implants, or the use of a reinforced framework. PURPOSE: This report evaluates subjects' satisfaction and prosthodontic maintenance during a 3-year randomized clinical trial of implant-retained mandibular complete dentures, whether reinforced or not with a cast framework, and attached by bar-clip or 2.25-mm ball-spring matrices to endosteal dental implants. MATERIALS AND METHODS: One hundred edentulous subjects, each having at least 1 year's experience with conventional complete dentures, were selected from respondents to a university dental clinic's request for volunteers. Candidates were examined to verify adequate mandibular bone and medical suitability for implants. Subjects then received 2 implants in the anterior mandible before being stratified by mandibular bone height and gender and assigned randomly to 1 of 4 treatment groups. Every subject received a new maxillary complete denture in addition to an implant-supported mandibular complete denture, with or without a reinforcing framework, connected to implants by either a bar-clip or a ball-spring patrix and matrix. The dentures were adjusted and repaired as needed. Subjects indicated on a visual analogue scale (VAS) satisfaction with conventional dentures prior to the study and then with new dentures at 1 month, 1 year, and 2 years. The results reported here are from the first 68 subjects observed for 3 years after receiving new dentures (19 subjects received new dentures less than 3 years before this analysis, and another 13 subjects were lost to follow-up). VAS scores are presented in simple tables and graphs, and results for different groups were compared using 2-sided nonparametric rank tests and repeated measures ANOVA. With respect to costs and maintenance, t tests were used to compare group means. Sample size and other design considerations used a .05 significance level. RESULTS: After receiving new dentures with mandibular implant supports, improved satisfaction "within subject" was prompt, durable, substantial, and statistically significant, regardless of the attachment mechanism, and with or without a reinforcing framework. In contrast, there were no notable satisfaction differences between the 2 attachment mechanisms, or with the presence or absence of a reinforcing framework, either at specific intervals after receiving the new dentures, or in repeated measures ANOVA. For both attachment groups, most denture adjustments occurred during the first year. This accounted for 81% of total adjustments during 3 years, when the 34 subjects in the ball-spring group and the 34 in the bar-clip group were combined. The mean numbers of adjustments per subject and associated clinical times did not differ significantly between the 2 groups. Conversely, denture repairs declined more slowly than adjustments. Almost all repairs (90%) occurred in the ball-spring group to correct problems with the attachments, 39% in the first year, and tapering off only slightly in the following 2 years. Over 3 years of follow-up, mean numbers of repairs per subject differed significantly between groups: 6.7 repairs per person in the ball-spring group, compared to 0.8 in the bar-clip group ( P<.001), and mean time per appointment was greater for repairs in the ball-spring group: 18.9 minutes compared to 16.9 ( P<.01). The cast framework had no influence on the satisfaction expressed or on adjustments and repairs. CONCLUSION: Subjects were very satisfied with the new dentures, although the ball-spring attachment tested in this trial required substantially more repairs.     

天然牙-种植体联合支持式义齿的应力分析

目的:比较以常规固定桥、固定式套筒冠和CEKA冠外精密附着体为上部结构的天然牙-种植体联合支持义齿的应力分布情况,寻求联合支持义齿上部结构的优化设计方案。方法:利用ANSYS三维有限元法,建立下颌右侧第一磨牙缺失、以下颌第二前磨牙和种植体(位于下颌第二磨牙)联合支持局部固定义齿的三维有限元模型,采用分散垂直和分散斜向(45°)两种加载方式(总加载力200N)。结果:2种加载条件下,固定式套筒冠和CEKA附着体都明显降低了种植体和天然牙周围骨组织的应力,垂直加载时,前者应力值低于后者;斜向加载时,后者低于前者,但后者会使天然牙局部应力有所增加。斜向加载时,种植体及其周围骨组织和天然牙及其周围骨组织的应力值均大于垂直加载条件下的应力值。结论:固定式套筒冠和CEKA附着体均能改善联合支持义齿的应力分布,CEKA附着体对侧向力的缓冲作用较优。