下颌第二磨牙半切术后固定修复的三维有限元分析

目的探讨下颌第二磨牙半切术后不同修复方式对基牙受力的影响,为临床修复设计提供依据。方法用三维有限元分析方法,分别模拟7近中根拔除、远中根保留和远中根拔除、近中根保留后固定桥修复,同时建立了司联冠修复和司缺失单基牙固定桥修复作为对照．比较载荷状态下基牙的受力状况。结果保留7远中根、固定修复6与正常情况下受力趋势相似。应力值较大;保留7近中根、单端固定桥修复司应力明显增大且峰值出现部位由颈部转移到根尖,但较司缺失、以6为基牙的单端固定桥受力合理。结论保留下颌第二磨牙远中根较保留近中根与第一磨牙联合修复后基牙受力合理：只要选择好适应症,保留近中根也是避免下颌第二磨牙缺失的一种方法。     

附着体义齿修复近中倾斜30°基牙的牙周组织应力分析

目的研究两种附着体义齿（栓道附着体义齿和套筒冠固定义齿）修复下颌第一磨牙缺失伴下颌第二磨牙近中倾斜30°的基牙的牙周组织应力分布。方法在已经建立的下颌第一磨牙缺失伴下颌第二磨牙近中倾斜30°修复前及两种附着体义齿修复后的三维有限元模型上,将200N垂直负荷和斜向负荷分别模拟加载于下颌第二磨牙,计算分析基牙牙周组织的应力情况。结果在下颌第二磨牙近中倾斜30°时,两种附着体义齿修复后倾斜基牙应力主要集中在其颈部牙槽骨或根分叉区。斜向加载下,栓道附着体义齿修复后倾斜基牙牙周组织应力小于套筒冠义齿修复。斜向加载下,下颌第二前磨牙和第二磨牙牙周组织应力远远大于垂直加载。结论在下颌第二磨牙近中倾斜30°时,栓道附着体义齿修复在改善倾斜基牙牙周组织应力方面更优于套筒冠义齿修复。斜向加载时,下颌第二前磨牙和第二磨牙牙周组织中产生较大的应力集中。     

正畸方法竖直下颌第三磨牙后修复下颌第一、二磨牙缺失1例

由于下颌第三磨牙前倾阻生,临床牙冠高度不足,无法利用该牙作基牙,制作义齿,修复下颌第一和第二磨牙的缺失.最近,我们对1例此类患者采用正畸的方法,首先推下颌第三磨牙向远中牙合向移动,使其临床牙冠接近于直立并与对颌牙形成良好的咬合关系,然后采用可摘局部义齿修复下颌第一、二磨牙缺失,取得了良好的疗效,报告如下:     

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。     

磨牙冠延长术在固定义齿修复中的应用

目的：观察磨牙冠延长术后作为固定义齿基牙的修复效果及相关问题。方法：临床牙冠殆龈距过小且被选为固定义齿基牙的末端磨牙21例，施以冠延长术，即翻瓣术或翻瓣术联合牙槽骨修整术，然后于2—8w后以固定义齿修复。6个月、1年后复查，检查修复体固位情况、固位体边缘、牙龈健康状况、龈沟出血指数等。结果：6-12个月后义齿固位良好，边缘密合，患者无不适，牙龈无明显红肿，龈沟出血指数与对称牙出血指数差异均无统计学意义（P〉0．05）。结论：对于临床牙冠短的磨牙，冠延长术是改善其固定修复效果的一种有效方法。     

利用倾斜下颌第三磨牙作固定桥

目的 利用倾斜第三磨牙制作固定桥,修复下颌磨牙缺失。方法 选择下颌第二磨牙或第一、第二磨牙都缺失且第三磨牙已有不同程度倾斜的病例１１例,通过纠正第三磨牙长轴后,以其作为固位体修复缺失牙。结果 随访１－３年,所的缺牙修复咀嚼功能良好,基牙无牙体牙周病变。结论 本方法扩大了固定桥的应用范围,同时保存了第三磨牙,并有效地恢复其咀嚼功能。     

隐形义齿与铸造支架义齿修复单侧磨牙缺失的体会

目的　观察隐形义齿与铸造支架可摘局部义齿修复单侧磨牙缺失的临床效果。方法　单侧磨牙缺失患者90例,随机分为2组,将采用隐形义齿组45例列为治疗组,将采用铸造支架式可摘局部义齿45例列为对照组。对其固位不良、食物嵌塞、基牙和软组织疼痛发生情况进行比较。结果　治疗组固位不良1例,食物嵌塞0例,基牙和软组织疼痛3例。对照组固位不良6例,食物嵌塞5例,基牙和软组织疼痛1例。结论　隐形义齿修复单侧磨牙缺失临床效果优于铸造支架式可摘局部义齿。     

口腔修复学——冠桥

IPS-Empress全瓷冠临床观察，套筒冠义齿修复上颌多数牙缺失4例报告，IPS-Empress瓷贴面修复前牙间隙2年的临床评价，计算机辅助设计中调控牙冠咬合面三维构型的模拟算法，烤瓷冠桩复合体三维有限元模型的建立，下颌第二磨牙缺失单端固定义齿修复的临床观察     

后磨牙残根残冠的多根桩修复

<正> 后磨牙是人体咀嚼功能的重要执行器官。临床上经常遇到后磨牙严重损坏——残根残冠的患者。过去对此种病况多在拔除残根残冠后行义齿修复,由于后磨牙承受猪力大,应用传统的固定义齿修复虽然效果较好,但对基牙的损伤较大;应用传统的可摘义齿修复其咀嚼功能及使用效果均不太理想;对于远端后磨牙缺失游离者,应用传统的固定或可摘义齿修复方法     

用三维有限元方法对单端固定桥进行应力分析

目的分析磨牙游离缺失单端固定桥修复的受力情况。方法运用三维有限元应力分析法,对一侧磨牙游离缺失通过改变牙槽骨支持高度,采用不同基牙数目,不同桥体长度建立不同的单端固定桥有限元模型进行应力和位移的计算和分析。结果较高的应力集中在游离端近中的基牙上,牙槽骨高度降低会增加基牙的移位及应力集中;单纯增加基牙的数目不会导致牙周组织中应力明显相应减少;基牙数目增加会减少修复体移位及应力集中;增加桥体长度会引起义齿应力明显增加和向远中移位。结论游离缺失端行单端固定桥修复最好选择桥体为一个磨牙长度,且基牙数至少两个,以提高单端固定桥修复的成功率。     

保留下颌第二磨牙近中根的修复治疗48例临床观察

收集本科48例远中根严重龋坏、吸收的下颌第二磨牙,分根拔除远中根,保留近中根,联合第一磨牙作为桥基牙单端固定桥修复第二磨牙.修复5年后复查,总有效率92.4%,固定桥能正常行使咀嚼功能.远中根严重龋坏吸收的第二磨牙保留近中根,单端固定桥修复第二磨牙疗效好.     

Three-dimensional finite element stress analysis of a cantilever fixed partial denture.

A three-dimensional mathematical model was generated, representing a three-unit cantilever fixed partial denture and its supporting mandibular structures. First and second premolars were used as abutments with one posterior cantilever pontic. A 5 lb vertical load was applied to the pontic. Vertical and horizontal stresses were analyzed by means of a three-dimensional finite element stress analysis technique. The results showed that a cantilever pontic creates considerable compressive stress on the abutment nearest to the pontic and produces tensile stress on the abutment farthest from the pontic.     

Extensive fixed partial dentures on mandibular canine teeth: a 5-year recall study

Twelve patients were followed for 5 years after treatment with a 12-unit cantilever fixed partial denture on the mandibular canines opposed by a complete maxillary denture. Two fixed dentures had to be removed, one because of an abutment tooth root-fracture and one because of rapid marginal bone loss in a terminal stage of leukemia. Caries and periodontal lesions were rare, but other complications, principally related to endodontics, occurred. All complications were amenable to standard treatment procedures. Extensive mandibular cantilever fixed partial dentures may be used in the rehabilitation of patients with a very reduced dentition and a history of difficulties in adapting to removable dentures.     

铸造支架联合NITI悬臂梁矫正舌倾下颌磨牙的临床效果评价

目的 评价NITI悬臂梁在矫正舌倾下颌磨牙中的临床效果。方法 选择16例单侧下颌第二磨牙舌倾的病例为研究对象,带垫铸造支架连接双侧下颌后牙,提供颌内支抗、解除咬合锁结,0.018英寸×0.025英寸或0.019英寸×0.025英寸NITI悬臂梁提供颊向旋转力矩和压低力。采用Graphpad Prism 6.0 软件对治疗前、后所测数据进行配对 t 检验。结果 所有患牙均获得直立,牙轴变化24°±1.2°（P<0.01）,近中舌尖到正中矢状面垂直距离变化（3±0.8） mm（P<0.05）,牙周状况良好,咬合关系稳定。结论 铸造支架联合NITI 悬臂梁可提供有效力学机制,矫正舌倾下颌磨牙。     

Monitoring trends in fixed partial denture design based on national surveys

To restore partially edentulous arches reasonable number of fixed partial dentures (FPD) are used in Hungary. This paper describes statistic parameters of these restorations based on analysis of a large sample size. Dentists of the Department of Prosthodontics performed oral health surveys according to WHO criteria, first survey in 1985-1989 and second in 2003-2004. The oral surveys were carried out at the lung cancer screening stations among those individuals originally referred to undergo x-ray lung screening examination. In the "first" survey data collected on 6224 FPD; in the "second" survey data collected on 3676 fixed restorations were analyzed. Besides time parameters, number of pontic teeth, abutment teeth to pontic teeth ratio (abutment saturation), position of pontic teeth in the arch, position of abutment teeth in the arch, main features of "tooth location" adjacent to restoration (remnant tooth, crown, artificial tooth, missing tooth), framework- and veneering materials were investigated. For interpreting data SPSS 10.0.5 for Windows was applied. Restorations' mean survival time was 9.34 +/- 8.47 years. Average number of FPD unit was: 6.34 for the maxillary and 4.62 for the mandibular jaw. Average number of abutment teeth was 3.58 in the upper and 2.82 in the lower jaw. Most frequent abutment teeth of both the maxillary and mandibular jaw were canines (23%) (20%). In order of frequency: pontics of the upper jaw replaced first premolars (27%) and second premolars (23%); lower jaw pontics replaced first molars (36%) and second premolars (21%). Findings of our survey demonstrated that results were much jaw dependent, while participants' sex and age influenced the outcome less. Comparison between left and right side of the arch revealed considerable symmetry. Recently collected data of 2004 have shown increased extension of fixed partial dentures with significantly higher number of abutment teeth involved. Statistical analysis of data collected on fixed partial dentures provide a sound basis for estimating the present oral health status of the population. Monitoring patterns of change have an important epidemiological relevance. Results of our present findings serve as a reliable source to plan future strategy of the dental care system and also helps to measure efficiency of the dental education system.     

Discrimination ability in patients with extensive fixed partial dentures on mandibular canine teeth

Carlson BR. Discrimination ability in patients with extensive fixed partial dentures on mandibular canine teeth. Acta Odontol Scand 1994;52:260–265. Oslo. ISSN ooO1-63S7.

To study discrimination ability under different test situations, a psychophysiologic test was performed in a group of patients with 12-unit mandibular fixed partial dentures supported on the 2 canines. The cantilever segments were exchangeable. Analyses of discrimination ability were performed with regard to periodontal and endodontic status of the abutment teeth and to type of mucosal contact in cantilever regions. Discrimination ability was markedly reduced with a strongly reduced periodontal bone contact area. The endodontic status did not affect discrimination ability. A tendency towards better discrimination ability was seen when the cantilever sections without mucosal contacts were compared with those with mucosal contacts through pontics or saddles.     

下颌第二、第三磨牙并列阻生的正畸矫治

目的探讨下颌第二、三磨牙并列阻生的正畸治疗方法,评估其效果。方法选择下颌第二、第三磨牙并列阻生患者6例、共8对,拔除下颌阻生第三磨牙,采用固定矫治器结合磨牙带环焊多曲推簧直立装置,对水平阻生的第二磨牙进行竖直,使第二磨牙远中直立移动。结果水平阻生第二磨牙全部被直立,达到正常的殆平面,获得良好功能邻接关系及根平行。X线片示原阻生牙冠所占空间为正常牙槽骨组织所修复。下颌阻生磨牙竖直时间为5～14个月,平均为8．63个月。结论在下颌第二、三磨牙并列阻生患者中,拔除下颌第三磨牙,有利于第二磨牙的直立。自制带环焊多曲推簧及粘接拉钩的磨牙竖直技术能有效地使水平阻生的第二磨牙产生快速的远中直立移动。     

下颌阻生第三磨牙阻生类型与第二磨牙损害相关性的影像分析

目的:探讨下颌第三磨牙的阻生情况,以及与相邻第二磨牙病损的相关性,为临床早期拔除高风险的下颌第三磨牙、预防第二磨牙病损提供依据。方法:根据纳入与排除标准,选择2015年9月—2017年9月在上海交通大学医学院附属第九人民医院放射科拍摄的全景片3000张（共4328颗下颌第三磨牙）,观察下颌第三磨牙阻生情况及相邻第二磨牙远中龋坏、牙周病、牙根吸收情况,使用R语言χ²检验统计分析其间的相关性。结果:阻生类型与第二磨牙病损均有相关性（P<0.001）;下颌第三磨牙近中阻生时,第二磨牙远中的龋坏率最高（P<0.001）;下颌第三磨牙垂直阻生和远中阻生时,第二磨牙的牙周病发生率最高（P<0.001）;下颌第三磨牙倒置阻生时,第二磨牙牙根吸收发生率最高（P<0.001）。结论:下颌阻生第三磨牙对其邻牙健康状况的影响程度较高,临床上建议早期拔除。     

Mechanical analysis of the effects of implant position and abutment height on implant-assisted removable partial dentures

PurposeAn increasing number of clinical reports describe the use of dental implants as abutments in implant-assisted removable partial dentures (IARPD). We used three-dimensional finite element analysis to evaluate IARPD as a unilateral mandibular distal extension denture. Specifically, the mechanical effects of implant position and abutment height on the abutment tooth, denture, and denture-supporting tissue were assessed.MethodsThe models analyzed were defects of the left mandibular second premolar and first and second molars prosthetically treated with an IARPD using one implant for each tooth position. There were two abutment heights: one equal to that of the mucosa and another that was elevated 2 mm above the mucosa. Six models were constructed.ResultsFor mucosal-level abutments, movement of the abutment tooth was lower for implants positioned distal to the abutment tooth than for those positioned medial to the abutment tooth. For elevated abutments, movement of the abutment tooth was lower for implants positioned medial to the abutment tooth than for those positioned distal to the abutment tooth.ConclusionsThe mechanical effects on abutment teeth at the same implant position differed in relation to implant abutment height.     

固定桥不同桥体龈端形态修复下颌第一磨牙的三维有限元分析

目的 应用三维有限元分析法探讨不同桥体龈端形态对固定桥基牙及牙周膜应力分布的影响.方法 利用健康成人牙列的锥形束CT(CBCT)原始数据,通过三维建模软件建立下颌第一磨牙缺失,第二前磨牙与第二磨牙为基牙的双端固定桥,并模拟三种不同桥体龈端形态,即改良鞍式、改良盖嵴式、船底式.利用Ansys 17.0对已建立的三种不同龈...