SJ—1型插销式附着体义齿支持组织的应力分析Ⅰ基牙数目的变化对？…

目的 观察ＳＪ－１型插销式附着体用于牙列末端游离缺损修复时,基牙数目的增减对支持组织应力分布的影响。方法 采用有限元分析法。结果 基牙数由３个减为２个,支持组织应力无明显增加,而由２个减为１个,支持组织应力明显增加,是前者的９倍。结论 提示临床应用该类修复方法时,一侧牙弓至少采用两单位联合基牙为适。     

SJ-1型插销式附着体义齿支持组织的应力分析 Ⅱ基牙牙槽骨不同程度吸收对支持组织应力分布的影响

目的观察ＳＪ－１型插销式附着体用于牙列末端游离缺损磨牙缺失修复时,基牙牙周组织伴有不同程度吸收对支持组织应力分布的影响。方法采用有限元分析法。结果基牙牙周组织吸收导致支持组织应力增加,但其分布形式没有改变。结论当第一双尖牙牙周组织的吸收大于第二双尖牙,且吸收不超过３０％,仍可作为首选基牙。     

SJ-1型插销式附着体义齿支持组织的应力分析 Ⅰ基牙数目的变化对支持组织应力分布的影响

目的观察ＳＪ－１型插销式附着体用于牙列末端游离缺损修复时,基牙数目的增减对支持组织应力分布的影响。方法采用有限元分析法。结果基牙数由３个减为２个,支持组织应力无明显增加。而由２个减为１个,支持组织应力明显增加,是前者的９倍。结论提示临床应用该类修复方法时,一侧牙弓至少采用两单位联合基牙为适。     

SJ—1型插销式附着体义齿的制作和临床应用

目的 为临床推广应用ＳＪ－１型插销式附着体义齿提供制作和使用的方法。方法 采用ＳＪ－１型插销式附着本修复１０例牙列末端游离缺失的病例,并经近两年临床观察随访。结果 患者戴用义的适应期明显缩短,咀嚼能力增加。结论 该义齿固位,稳定作用良好,咀嚼效能明显改善且美观舒适。     

游离端可摘局部义齿附着体及其基牙、支持组织的应力分析

游离端缺失时远中无基牙支持,承受(牙合)力时应力的分布较特殊,是修复临床复杂但又常见的情况.附着体是由阴型和阳型两部分组成的精密嵌合体.应用附着体固位的可摘局部义齿(RPD)有良好的固位与稳定等优点.正确的选择适当类型的附着体进行RPD修复,需要分析修复体受力后基牙和剩余牙槽嵴的受力特点,以及减小应力或使其分布更为合理的方法.本文对关于游离端RPD附着体的一些相关理论和最新应力研究结果加以综述,以期帮助临床工作.     

SJ—1型插销式附着体可摘义齿的咀嚼效能分析

目的 对戴有SJ－1型插销式附着体义齿的患者进行咀嚼效能的测试分析。方法 选择16例末端游离缺失患者,用SJ－1型附着体义齿修复后,采用吸光度法测定咀嚼效能,并与正常组及戴传统义齿者比较。结果 16例患者初戴附着体义齿1周后吸光度均值为0．876。3周后为0．859,1月后为0．985,无显著差异。与正常牙列者吸光度均值比较,P＞0．05,与戴传统活动义齿者比较,P＜0．01,有高度显著性差异。结论 SJ－1型插销式附着体义齿比传统的可摘义齿能更好地恢复患者的咀嚼功能。     

SD附着体固位远中游离端可摘局部义齿三维有限元应力分析

目的：对比分析刚性及弹性附着体义齿的应力分布，为临床选用附着体提供理论参考。方法：建立下颌第二磨牙游离缺失的附着体义齿三维模型。采用有限元应力分析方法，分析2种附着体义齿基牙应力分布情况。结果：（1）在垂直载荷下，2种附着体基牙在牙槽嵴顶处均有应力集中。弹性附着体基牙牙根主应力下降26％-58％；剩余牙槽嵴应力峰值减小50％。（2）斜向载荷时，应力集中更明显，弹性附着体应力峰值仍有一定减小。结论：弹性附着体固位的可摘局部义齿，更有利于保护基牙及支持组织，保护剩余牙槽嵴。     

精密附着体固位型可摘义齿

目的:介绍精密附着体固位型义齿的设计原则,制作方法,评价其临床效果。方法:采用Bredent球状和杆状精密附着体系统,为21名患者设计制作了30件义齿,53副精密附着体。结果:最长者经3年零10个月观察,临床效果良好。结论:患者戴用该型义齿后,咀嚼功能好,稳固、摘戴方便、美观舒适,基牙无病变     

精密附着型可摘局部义齿

精密附着体是一类在欧美广泛应用的固位体，它能很好地保护基牙，具有固位作用强、美观等优点。本文介绍了几种常见的冠内、冠外ＰＡ，它们的适应证以及应用它们固位义齿临床技工室操作技术要点。同时介绍了ＰＡ的最新应用进展。     

改良杆卡式附着体与不同可摘局部义齿对支持组织应力分布的研究

目的探讨改良杆卡式附着体义齿与RPI卡环组、联合卡环组可摘局部义齿修复单侧游离缺失对支持组织的应力分布。方法在下颌47、46单侧游离缺失的环氧树脂模型上分别以改良杆卡式附着体、RPI卡环组、联合卡环组3种固位形式的可摘义齿修复,用三维光弹应力冻结切片技术测试义齿加载后对基牙和缺牙区牙槽骨应力分布。结果对基牙牙槽骨的应力：改良杆卡式附着体义齿〉RPI卡环组〉联合卡环组（P〈0．05）;附着体义齿对基牙的近、远中应力无显著性：差异（P〉0．05）;RPI卡环组义齿有猞支托处的应力大于无拾支托处的应力（P〈0．05）;联合卡环组对远中的应力大于近中（P〈0．05）。对缺牙区牙槽骨应力：改良杆卡式附着体与RPI卡环组均小于联合卡环组（P〈0．05）;附着体义齿、RPI对缺牙区牙从近中到远中的4个切片应力无显著性差异（P〉0．05）,联合卡环组远中大于近中（P〈0．05）。结论改良杆卡式附着体义齿有应力中断作用,各点应力分布较均匀。RPI固位的活动义齿应力主要分布在基牙上,缺牙区应力稍小。联合卡环组义齿对失牙区的应力最大,基牙上应力较小。     

冠外固位体义齿基牙牙周组织应力分布的三维有限元分析

目的研究下颌第一磨牙缺失、第二磨牙近中倾斜30°或45°时,用栓道附着体义齿或套筒冠义齿2种冠外固位体(extra-coronal retainer,ECR)义齿修复的基牙牙周组织应力分布。方法采用CT扫描技术和Mimics、Freeform、ANSYS软件,建立下颌第一磨牙缺失、第二磨牙近中倾斜30°或45°及ECR义齿修复后的三维有限元模型,模拟加载并计算分析基牙牙周组织应力的分布情况。结果下颌第二磨牙近中倾斜30°、45°模型,修复前第二前磨牙Von Mises应力分别是2.80 MPa、3.47 MPa,栓道附着体义齿修复后分别是19.26 MPa、25.18 MPa,套筒冠义齿修复后分别是19.47 MPa、24.48 MPa,ECR义齿修复后下颌第二前磨牙牙周组织应力明显增大;修复前第二磨牙Von Mises应力分别是20.45 MPa、20.50 MPa,栓道附着体义齿修复后分别是15.02 MPa、11.84 MPa,套筒冠义齿修复后分别是18.04 MPa、12.18 MPa,ECR义齿修复后下颌第二磨牙牙周组织应力明显减小。结论栓道附着体义齿和套筒冠义齿均能改善倾斜基牙牙周组织的应力分布,当下颌第二磨牙近中倾斜角度过大或下颌第二前磨牙牙周状况欠佳时,应该考虑增加近中端基牙数目。     

Impaired masticatory behavior in subjects with reduced periodontal tissue support

BACKGROUND: Mechanoreceptors situated in the periodontal ligament provide detailed information about intensive and spatial aspects of tooth loads, which support the neural control of masticatory forces. We asked whether a reduced periodontal ligament due to periodontitis, and, thus, an altered mechanoreceptive innervation of the teeth, would affect masticatory behavior when subjects used incisors to hold and split food. METHODS: We tested 11 subjects with reduced periodontal tissue support that rendered 30% to 70% alveolar bone loss for at least one pair of opposing anterior incisors. Forces were recorded when subjects used their affected incisors to hold half of a peanut for approximately 4 seconds and then split it. Age- and gender-matched healthy subjects served as the control group. None of the participants showed acute oral symptoms or massive periodontal inflammation. RESULTS: The test group used greater force when holding food between the teeth (1.1+/-0.4 N [ mean+/-1 SD]) compared to the control group (0.4+/-0.2 N). Hold forces used by subjects in the test group were also more variable, both within and between trials. The increase in bite force applied to split the peanut was slower and more hesitant for subjects in the test group compared to the control group. CONCLUSIONS: Reduced periodontal tissue support accompanies impaired regulation of masticatory forces. Faulty mechanoreceptive innervation of the periodontal ligament explains the elevated hold force, whereas a change in biting strategy due to the weakened support of the teeth may account for the more defensive food-splitting behavior.     

弹性义齿对基牙牙周牙体组织健康影响的研究

选择2005年1月至2010年1月在我院行弹性义齿修复患者65例,其中男性35例,女性30例,年龄15-72岁,共计65件修复体,均为前牙缺失,单个前牙缺失43件,2个及以上前牙缺失22件,     

Maximal bite force in patients with reduced periodontal tissue support with and without splinting

BACKGROUND: Chewing and biting forces are supposed to be limited by sensory input from periodontal mechanoreceptors. This is why the threshold level of those receptors should be lower in teeth with reduced periodontal tissue support. The purposes of the present study were to evaluate the influence of reduced periodontal tissue support on maximal bite force in natural dentitions and to study the effect of splinting on maximal bite force. METHODS: In 10 patients with reduced periodontal tissue support (test), as well as in 10 periodontally healthy subjects (control), maximal bite force was measured. The remaining periodontal ligament area in the test group was calculated from x-rays. Bite force was assessed at 4 mm mouth opening in the premolar region without and following splinting of the posterior teeth and transduced using a strain-gauge (full-bridge circuit). Maximal bite force measured with and without splinting was compared between test and control subjects, and within each group. RESULTS: In test subjects, the mean periodontal ligament area was 48.5% (SD = 10.1) across first premolars and 50.0% (SD = 12.2) across posterior teeth (control: 100%). In test subjects, the mean maximal bite force without splinting was 357 N (SD = 70), and in control subjects, 378 N (SD = 66; P > 0.05). After splinting, the bite force in test subjects was 509 N (SD = 75), and in control subjects, 534 N (SD = 49; P > 0.05). Bite force before and after splinting was P < 0.05 within each group. CONCLUSIONS: Reduced periodontal tissue support does not seem to limit bite force with maximal strength in natural dentitions as measured by a device that opens the bite by 4 mm. Furthermore, maximal biting forces at 4 mm mouth opening are increased when molar teeth are included in a posterior splint.     

Retrospective evaluation of complete-arch fixed partial dentures connecting teeth and implant abutments in patients with normal and reduced periodontal support

STATEMENT OF PROBLEM: The clinical outcome of complete-arch fixed prostheses supported by implants and natural tooth abutments in patients with normal or reduced periodontal support has been reported by few studies, with controversial results. PURPOSE: The purpose of this study was to report on the implant success rate, prosthetic complications, and the occurrence of tooth intrusion, when complete-arch fixed prostheses, supported by a combination of implants and teeth, were fabricated for patients with normal and reduced periodontal support. MATERIAL AND METHODS: Nineteen patients with residual teeth that served as abutments were consecutively treated with combined tooth- and implant-supported complete-arch fixed prostheses and were retrospectively evaluated after a period varying from 24 to 94 months. Nine patients showed reduced periodontal support as a result of periodontal disease and treatment (RPS group), and 10 patients had normal periodontal support of the abutment teeth (more than 2/3 of periodontal support [NPS group]). Ninety implants and 72 tooth abutments were used to support 19 fixed partial dentures. Screw- and cement-retained metal-ceramic and metal-resin prostheses were fabricated with rigid and nonrigid connectors. Implant survival and success rates, occurrence of caries and tooth intrusion, and prosthetic complications were recorded. The number of teeth, implants, prosthetic units, fixed partial dentures, and nonrigid connectors were compared with a t test to assess differences between the 2 groups, while data for the occurrence of intrusions and prosthetic complications were compared with the Fisher exact test (alpha=.05). RESULTS: One of the 90 implants was lost (99% survival rate) over 24 to 94 months, while 3 implants showed more than 2 mm of crestal bone loss (96% success rate) over the same period. No caries were detected, but 5.6% (4/72) of the abutment teeth exhibited intrusion. Intrusion of abutment teeth was noted in 3 patients who had normal periodontal support (13% of teeth in NPS group) of the abutment teeth and was associated with nonrigid connectors. No intrusion of teeth was noted in the patients exhibiting reduced periodontal support regardless of the type of connector or when a rigid connector was used for either group. The number of intruded teeth was significantly greater in patients with intact periodontal support (P=.03). CONCLUSIONS: Complete-arch fixed prosthesis supported by implant and tooth abutments may be associated with intrusion of teeth with intact periodontal support when nonrigid connectors are used to join the implant- and tooth-supported sections of the prostheses. However, fixed partial dentures supported by implants and teeth with reduced periodontal support were not associated with tooth intrusion, regardless of the type of connectors used.