Dentis种植系统的临床效果观察

目的：探讨Dentis种植系统的临床应用效果。方法：对132例牙列缺损患者行Dentis种植体植入,3-6个月后行上部义齿修复,并进行临床和放射学的随访观察。结果：206枚种植体中有2枚在修复后6个月内脱落,其余未见松动、脱落和植入体根周X射线透射区,留存率99.0%,成功率99.0%。结论：选择合适的病例,配合应用相应术式,Dentis种植系统的临床应用效果良好。     

重组人骨保护素对聚乙烯颗粒刺激的人工关节置换术患者外周血IL-6和TNF-α表达的影响

目的：探讨重组人骨保护素（rhOPG）对聚乙烯颗粒刺激的人工关节置换术患者外周血IL一6和TNF一0l表达的影响,分析rhOPG防止关节置换术后假体无菌性松动的应用价值。方法：收集2009年1月-2011年3月我院收治的人工关节置换术患者的外周血清60份,采用梯度离心法分离出单个核细胞,并将其随机分成5组,每组12份。对照组：单个核细胞,模型组：单个核细胞＋1X109／mL聚乙烯颗粒,低剂量组：单个核细胞＋1×109／mLL聚乙烯颗粒＋10ng／mLrhOPG,中剂量组：单个核细胞＋1X109／mL聚乙烯颗粒＋100ng／mLrhOPG,高剂量组：单个核细胞＋l×109／mL聚乙烯颗粒＋1000ng／mLrhOPG。通过酶联免疫酶联免疫法（ELISA）＇~4定各组细胞上清液中白介素-6（IL-6）和肿瘤坏死因子（TNF-α）的含量,并进行组间比较。结果i（1）模型组、低剂量组、中剂量组、高剂量组的IL-6、TNF-α．含量均显著高于对照组（P〈0．05）。（2）低剂量组、中剂量组、高剂量纽的IL-6、TNF—α浓度均较模型组低（P〈0．os）。（3）随着rhOPG浓度的增加,IL-6和TNF．仪含量逐渐降低,组间比较差异有统计学意义（P〈0．05）。结论irhOPG可抑制聚乙烯颗粒刺激的人工关节置换术患者外周血1L-6和TNF—α．的表达,可有助于防治人工关节置换术后的无菌性关节松动。关键词：人工关节置换术;重组人骨保护素;假体松动;白细胞介素-6;肿瘤坏死N子     

Predicting bone remodeling around tissue- and bone-level dental implants used in reduced bone width

The objective of this study was to predict time-dependent bone remodeling around tissue- and bone-level dental implants used in patients with reduced bone width. The remodeling of bone around titanium tissue-level, and titanium and titanium–zirconium alloy bone-level implants was studied under 100 N oblique load for one month by implementing the Stanford theory into three-dimensional finite element models. Maximum principal stress, minimum principal stress, and strain energy density in peri-implant bone and displacement in x- and y- axes of the implant were evaluated. Maximum and minimum principal stresses around tissue-level implant were higher than bone-level implants and both bone-level implants experienced comparable stresses. Total strain energy density in bone around titanium implants slightly decreased during the first two weeks of loading followed by a recovery, and the titanium–zirconium implant showed minor changes in the axial plane. Total strain energy density changes in the loading and contralateral sides were higher in tissue-level implant than other implants in the cortical bone at the horizontal plane. The displacement values of the implants were almost constant over time. Tissue-level implants were associated with higher stresses than bone-level implants. The time-dependent biomechanical outcome of titanium–zirconium alloy bone-level implant was comparable to the titanium implant.     

Biomechanical analysis and comparison of 12 dental implant systems using 3D finite element study

Finite element analysis plays an important role in dental implant design. The objective of this study was to show the effect of the overall geometry of dental implants on their biomechanics after implantation. In this study, 12 dental implants, with the same length, diameter and screw design, were simulated from different implant systems. Numerical model of right mandibular incisor bone segment was generated from CT data. The von-Mises stress distributions and the total deformation distributions under vertical/lateral load were compared for each implant by scores ranking method. The implants with cylindrical shapes had highest scores. Results indicated that cylindrical shape represented better geometry over taper implant. This study is helpful in choosing the optimal dental implant for clinical application and also contributes to individual implant design. Our study could also provide reference for choice and modification of dental implant in any other insertion sites and bone qualities.     

Three-dimensional numerical simulation of stress induced by different lengths of osseointegrated implants in the anterior maxilla

Lower survival rates were observed for the implant placed in the anterior maxilla. The purpose of this study was to investigate the influence of different implant lengths on the stress distribution around osseointegrated implants under a static loading condition in the anterior maxilla using a three-dimensional finite element analysis. The diameter of 4.0 mm external type implants of different lengths (8.5 mm, 10.0 mm, 11.5 mm, 13.0 mm, 15.0 mm) was used in this study. The anterior maxilla was assumed to be D3 bone quality. All the material was assumed to be homogenous, isotropic and linearly elastic. The implant–bone interface was constructed using a rigid element for simulating the osseointegrated condition. Then, 176 N of static force was applied on the middle of the palatoincisal line angle of the abutment at a 120°angle to the long axis of abutment. The von Mises stress value was measured with an interval of 0.25 mm along the bone–implant interface. Incremental increase in implant length causes a gradual reduction of maximum and average von Mises stress at the labial portion within the implant. In the bone, higher stress was concentrated within cortical bone area and more distributed at the labial cortex, while cancellous bone showed relatively low stress concentration and even distribution. An increase in implant length reduced stress gradients at the cortical peri-implant region. Implant length affects the mechanisms of load transmission to the osseointegrated implant. On the basis of this study the biomechanical stress-based performance of implants placed in the anterior maxilla improves when using longer implants.     

Computational simulation of internal bone remodelling around dental implants: a sensitivity analysis

This study aimed to predict the distribution of bone trabeculae, as a density change per unit time, around a dental implant based on applying a selected mathematical remodelling model. The apparent bone density change as a function of the mechanical stimulus was the base of the applied remodelling model that describes disuse and overload bone resorption. The simulation was tested in a finite element model of a screw-shaped dental implant in an idealised bone segment. The sensitivity of the simulation to different mechanical parameters was investigated; these included element edge length, boundary conditions, as well as direction and magnitude of the implant loads. The alteration in the mechanical parameters had a significant influence on density distribution and model stability, in particular at the cortical bone region. The remodelling model could succeed to achieve trabeculae-like structure around osseointegrated dental implants. The validation of this model to a real clinical case is required.     

Computational modelling and optimisation of soft tissue outcome in cranio-maxillofacial surgery planning

Cranio-maxillofacial (CMF) surgery operations are associated with rearrangement of facial hard and soft tissues, leading to dramatic changes in facial geometry. Often, correction of the aesthetical patient's appearance is the primary objective of the surgical intervention. Due to the complexity of the facial anatomy and the biomechanical behaviour of soft tissues, the result of the surgical impact cannot always be predicted on the basis of surgeon's intuition and experience alone. Computational modelling of soft tissue outcome using individual tomographic data and consistent numerical simulation of soft tissue mechanics can provide valuable information for surgeons during the planning stage. In this article, we present a general framework for computer-assisted planning of CMF surgery interventions that is based on the reconstruction of patient's anatomy from 3D computer tomography images and finite element analysis of soft tissue deformations. Examples from our clinical case studies that deal with the solution of direct and inverse surgical problems (i.e. soft tissue prediction, inverse implant shape design) demonstrate that the developed approach provides a useful tool for accurate prediction and optimisation of aesthetic surgery outcome.     

即刻种植修复与延期种植修复对上颌单前牙患者牙周组织健康、美学效果以及炎症因子的影响

摘要 目的：探讨即刻种植修复与延期种植修复对上颌单前牙患者牙周组织健康、美学效果以及炎症因子的影响。方法：回顾性分析2017年3月~2018年12月期间收治的80例上颌单前牙患者的临床资料,根据种植修复方式的不同分为A组（n=40,延期种植修复）和B组（n=40,即刻种植修复）,比较两组患者植牙成功率、牙周组织健康、美学效果、炎症因子及并发症。结果：两组植牙成功率比较无差异（P>0.05）。两组修复后1个月、3个月、6个月、12个月牙周袋深度依次降低（P<0.05）;B组修复后1个月、3个月、6个月、12个月牙周袋深度均低于A组（P<0.05）。两组修复后1个月、3个月、6个月、12个月红色美学指数（PES）评分依次升高（P<0.05）;B组修复后1个月、3个月、6个月、12个月PES评分均高于A组（P<0.05）。两组修复前、修复后7 d、修复后30 d血清肿瘤坏死因子-α（TNF-α）、C反应蛋白（CRP）水平均呈升高后降低趋势,B组修复后7 d、修复后30 d血清TNF-α、CRP水平均低于A组（P<0.05）。两组均未见严重并发症发生。结论：与延期种植修复相比,即刻种植修复治疗上颌单前牙患者对其牙周组织健康改善效果更佳,且炎症反应更轻微 ,美学效果更好,疗效显著且安全性好。     

老年糖尿病患者牙周重度破坏后种植研究

目的:研究2型糖尿病老年患者牙周重度破坏后不同血糖水平对于牙齿种植术后炎症指标、种植体稳定性及菌斑指数的影响,探讨患者血糖控制情况和种植牙术后效果的关系。方法:选取我院2011年1月至2013年1月40例在牙周重度破坏后行种植体置入的2型糖尿病老年患者,按照术后8周糖化血红蛋白水平是否≥7.5%分为实验组和对照组,分别测定两组患者术后24小时血常规,对比其白细胞、中性粒细胞及淋巴细胞水平;同时于术后第4、8、12周检测其种植体稳定参数(ISQ);术后3个月、6个月检测其菌斑指数(PLI)。结果:术后24小时,实验组的白细胞、中性粒细胞及淋巴细胞水平显著高于对照组,P0.01;术后第4、8、12周的ISQ值,实验组显著低于对照组,P0.01;术后3个月、6个月的菌斑指数,实验组显著高于对照组,P0.01。结论:2型糖尿病老年患者牙周重度破坏后不同血糖水平与其炎症反应、种植体稳定性及细菌繁殖情况密切相关,控制术前及术后血糖,有利于提高种植体稳定性并降低术后炎症反应,减少细菌繁殖,促进尽早愈合。