标尺模板在Branemark种植修复中的制作和应用

目的:制作并观察标尺模板在指导Branemark种植手术,提高手术安全性方面的作用。方法:选择15例患者52颗种植体,铸造制作标尺模板后戴入口腔拍摄曲面体层片。根据影象所显示的适宜种植区域与颏孔、上颌窦等颌骨重要解剖结构的位置,结合上部修复设计选择Branemark种植体数量与植入点,并借助标尺模板的定位网格予以记录。手术时将标尺模板戴入口腔,根据记录结果在颌骨表面显示种植体入点与颌骨重要解剖结构的位置,指导手术进行。术后戴入标尺模板拍摄对照片,判断种植体与预定位置的吻合性。结果:52颗种植体中,除1颗种植体因术中临时改变种植位置,其余51颗种植入位置均与术前计划一致。结论:在Branemark种植修复中制作并应用标尺模板,能方便直观地帮助术者将种植体植入预定位置,避免损伤颏孔等颌骨重要解剖结构,提高了手术的正确性与安全性。     

影响口腔种植及修复成功的因素分析

目的:总结分析影响口腔种植和修复成功的因素。方法:回顾性分析我院2013年4月~2015年5月的300例患者,并结合相关文献总结影响口腔种植和修复成功的因素。结果:300名患者有276人口腔植入及植入成功,成功率为92%。不成工的案例中,受到个人因素影响失败的12人,在种植技术方面失败的12人。结论:对于口腔种植和修复成功的因素分为患者个人和修复技术两方面。需要患者调整好自身状态,同时我们也应该加强种植及修复的精确度。     

口腔种植材料表面特性与生物膜形成研究进展

人类口腔环境为微生物提供了适宜生存的条件,多种微生物在牙齿表面形成了由基质包裹相互粘附的口腔生物膜,口腔生物膜是口腔微生物生存、代谢和致病的基础。随着1965年Brnemark种植体在临床上的成功应用,种植相关材料周围致病菌导致的种植体周围炎成为种植修复最常见的并发症之一,影响种植修复的远期效果。种植体周围炎引起了许多关注,并且口腔种植材料表面的特性和口腔生物膜的形成密切相关。本文就种植材料及天然牙齿表面的生物膜形成、种植材料表面特性对口腔生物膜及细菌粘附的影响因素、增强种植材料抗菌性能的方法以及未来的研究方向等作一综述。     

数字式一体化口腔临床工程系统的研制

运用数字总线技术实现多模块化控制,对CT或X光片、口腔数字化扫描仪、印模扫描图像等进行三维重建、立体构图,开发系列规划软件,为口腔医生提供优化治疗、修复方案。同时,计算机可联接微型CAD／CAM自动进行义齿、贴面快速加工,以及种植导板等产品的设计、加工;联接手术导航仪进行牙种植手术导航;联接PACS、HIS等系统,实现数字化图像传输以及远程医疗功能。在诊所内一体化完成诊断、治疗、制作、修复、整形、美容等系列复杂、精细工作。     

静态与动态计算机辅助种植手术在口腔种植中的应用进展

牙齿缺失是常见的口腔疾病,可导致患者咀嚼功能降低,面部形态改变。种植牙成为了修复缺失牙的最佳选择。计算机辅助技术在口腔领域的应用,为临床医生提供更多修复缺失牙的手术方法。静态计算机辅助种植手术与动态计算机辅助种植手术修复缺失牙是计算机辅助种植手术的两种主要手术方式。这两种种植手术解决了患者咀嚼功能和面部美观问题,但其在临床应用中仍有一定的局限性。本文通过论述静态计算机辅助种植手术与动态计算机辅助种植手术的概念及分类,通过论述其使用过程中的优点、缺点,对比两种手术方式植入的种植体精确度以评估其在临床中的应用,探讨如何在临床应用中减少种植体的偏差,为临床医生在种植病例的手术方法选择提供参考。     

下颌种植覆盖义齿的生物力学研究进展

口腔生物力学是用生物力学的概念和方法,研究口腔医学中的有关基础性科学问题、解决口腔医学中的临床实际问题、发展口腔临床技术的一门学科。在口腔正畸学、修复学、种植学及口腔颌面外科学等领域存在着大量的生物力学问题,生物力学已成为口腔医学的基础科学之一。传统全口义齿修复常常会出现固位稳定差、咀嚼效率低、患者有疼痛感、适应时间长等情况,很大程度上不能满足患者的修复要求。种植覆盖义齿对于下颌牙槽嵴严重吸收的患者,效果尤为明显。种植覆盖义齿是义齿与种植体之间以不同的附着体作为连接,形成患者可以自行摘戴的种植体支持的覆盖义齿修复。下颌种植覆盖义齿因其能有效地提高下半口义齿的固位性和稳定性、显著提高了患者的咀嚼效率,目前已成为修复下颌牙槽骨严重吸收的无牙颌患者的有效修复方法。本文针对下颌种植覆盖义齿的生物力学研究进展作一综述。     

计算机辅助设计与制作（CAD—CAM）在口腔科的应用

CAD—CAM在口腔临床上的应用,尤其在口腔修复科全瓷冠、套筒冠的修复以及口腔种植领域的应用,提高了修复体的制作效率和质量。该文就CAD—CAM在口腔修复中的应用新进展作一综述。     

快速成型技术在颌骨缺损修复中应用的临床研究

目的：研究以CAD／CAM快速成型模型预成钛支架行颌骨缺损功能和外形重建的临床疗效。方法：选择四川大学华西口腔医院收治的5例颌骨良性肿瘤患者,术前螺旋CT及快速成型技术预成实体模型,并通过反求工程技术将健侧颌骨外形复制,制备钛修复体行患侧缺损修复,观察术后效果。结果：术后3个月、6个月复查患者对自身颌骨功能及外形较满意,均未出现因修复体导致的严重不良反应,张口度都接近恢复至正常,张口运动未出现明显异常,咬合关系良好。结论：运用快速成型技术设计并利用反求工程技术制造的个性化修复体进行颌骨缺损修复的方法能较好地恢复患者颌面部的功能和外形,副反应小,可以达到比较满意的修复效果。     

人工骨表面覆盖口腔修复膜对颌骨囊性缺损人工骨植入术患者植入腔感染的预防作用

目的:探讨人工骨表面覆盖口腔修复膜对颌骨囊性缺损人工骨植入术患者植入腔感染的预防作用。方法:将我院2012年4月～2016年2月收治的78例颌骨囊性缺损患者按治疗时间分为对照组38例与观察组40例,均行开窗人工骨植入术,其中对照组采取常规抗感染,观察组采取人工骨表面覆盖口腔修复膜。比较两组的囊腔体积、面积缩减率、人工骨植入量、骨厚度及植入腔感染率。结果:两组的囊腔体积、面积缩减率及人工骨植入量比较差异无统计学意义(P0.05)。但观察组的骨厚度明显大于对照组(P0.05),植入腔感染率明显低于对照组(P0.05)。结论:在开窗人工骨植入术的基础上使用口腔修复膜不仅能引导骨组织再生,而且能够显著降低植入腔的感染率。     

半导体激光在口腔临床医疗中的应用和研究进展

激光在口腔领域中的应用越来越多。半导体激光以其诸多的优点,在口腔领域的应用也越来越广泛,现就半导体激光在口腔内科、口腔正畸学、口腔修复学、口腔种植学以及颌面外科等领域的临床应用现状及目前的研究进展加以综述。     

Stability of dental implants in microvascular osseous transplants

Microvascular iliac crest and scapula transplants have been used in reconstruction of the lower jaw following tumor surgery. It has only been with the insertion of dental implants that a satisfactory prosthetic rehabilitation of the patient has been achieved. For this study, a follow-up of 38 patients with lower jaw tumors was carried out. The patients had been treated with partial resection of the lower jaw and neck dissection with microvascular iliac crest transplants (n = 20) or microvascular scapula transplants (n = 18); this was followed with dental implants (n = 143) in the region of the transplants or the local lower jaw. One hundred thirty-nine of the 143 dental implants were loaded by prosthetic superstructures. In all patients, the implant situation was evaluated on average 2 years 5 months after implantation. Periotest values, periimplant probing depths, and contact bleeding were registered, and the extent of periimplant bone loss was defined radiographically. The clinical situation in the region of the implant was compared for both types of implants and also with the nonresected lower jaw. The average Periotest values were within the normal range for all groups. In one scapula implant, however, a better average of Periotesting, -3.3, was found compared with implants of the iliac crest with Periotest values of -0.7. A measurement of -2.1 was found for the local lower jaw, similar to that of scapula implants. Pathologic probing depths were found for all three compared groups. The radiographically determined vertical loss of bone was the same for all three groups, on average 1 mm at 27 months postoperatively. The highest incidence of sulcus bleeding was found in the scapula implant group. Thus, it can be stated that the scapula transplants provide a similar transplant site to local lower jaw bone, whereas implants in iliac crest transplants show lesser bony stability. Periimplant soft-tissue conditions are worse for both types of transplants compared with local tissue of the lower jaw.     

Tooth reorientation affects tooth function during prey processing and tooth ontogeny in the lesser electric ray, Narcine brasiliensis

The dental anatomy of elasmobranch fishes (sharks, rays and relatives) creates a functional system that is more dynamic than that of mammalian dentition. Continuous dental replacement (where new teeth are moved rostrally to replace older ones) and indirect fibrous attachment of the dentition to the jaw allow teeth to reorient relative to the jaw over both long- and short-term scales, respectively. In this study, we examine the processing behavior and dental anatomy of the lesser electric ray Narcine brasiliensis (Olfers, 1831) to illustrate that the freedom of movement of elasmobranch dentition allows a functional flexibility that can be important for complex prey processing behaviors. From static manipulations of dissected jaws and observations of feeding events in live animals, we show that the teeth rotate during jaw protrusion, resulting in a secondary grasping mechanism that likely serves to hold prey while the buccal cavity is flushed free of sediment. The function of teeth is not always readily apparent from morphology; in addition to short-term reorientation, the long-term dental reorientation during replacement allows a given tooth to serve multiple functions during tooth ontogeny. Unlike teeth inside the mouth, the cusps of external teeth (on the portion of the tooth pad that extends past the occlusal plane) lay flat, such that the labial faces act as a functional battering surface, protecting the jaws during prey excavation.     

Densitometric analysis of dental implant placement between flapless technique and the two-stage technique--a pilot study

Flapless technique is a surgical approach of implant placement without raising a mucoperiosteal flap. Such approach has many advantages: shorter surgical treatment, minimal bleeding, postoperative discomfort for the patient is reduced; possibility of immediate loading of the inserted implant, faster procedure of implant placement and by that less time is needed for the complete implant-prosthetic restoration. Purpose of this pilot study was radiographic assessment of flapless technique and determination of its clinical values in comparison with two-stage dental implant technique through computerized densitometric analysis. The sample consisted of 10 patients with missing teeth in the premolar region in the upper jaw. An implant was placed in that position. In the first group of 5 patients the implants were inserted with the flapless technique, and in the other group of 5 patients implant insertion was done with a two-stage technique. All inserted implants were loaded with metal-ceramic crowns 3 months after placement. The patients were followed for 18 months through clinical follow-ups and radiovisiographical (RVG) images made after 3, 12 and 18 months. After comparing the average densities, the results showed similar decrease of density in both groups, conventional two-stage technique showed 3.24 and flapless technique 1.23. It can be concluded that flapless technique in everyday clinical usage has the same result as the two-stage dental implant technique.     

Arch form,tooth size,and occlusomandibular kinesis in the Ceboidea

Correlations between dental morphology, arch configuration, and jaw movement patterns were quantitatively investigated in 23 ceboid species to elucidate integrative aspects of occlusal functional anatomy in an adaptive and evolutionary context. Differential maxillary-mandibular arch widths are primary in guiding lateral jaw movements. These movements are characterized according to their associated condylar shifts as either predominantly translatory or rotational. Predominantly translatory movements result from peripheral contact relationships between maxillary arches which are considerably wider posteriorly than their opposing mandibular arches. The greatest degree of mandibular movement is in the molar region in functional association with wide “primitive” maxillary molars, narrow mandibular molars, constricted maxillary intercanine widths, and narrow maxillary incisors. In contrast, predominantly rotational masticatory jaw movements result from differential arch widths which are greatest in the maxillary canine and incisor regions. Here most jaw movement is in the anterior segment and this is reflected in small maxillary-mandibular molar width differences, a high degree of premolarization, wide-set maxillary canine teeth, and wide maxillary incisors. Possible selectional factors in the putative evolution of rotational predominance in mastication from the more primitive translatory pattern are discussed.     

Global biomechanical model for dental implants

The osseointegration of titanium dental implants is a complex process and there is a need for systematization of the factors influencing anchoring of implant. A common way of analyzing the strength of the fixation in bone is by measuring the torque required to remove the implants after healing. In this paper, a global biomechanical model is introduced and derived for removal torque situations. In this model, a gap is allowed to form between the bone and the implant and the size of the gap at fracture is a function of the surface roughness and can be shown to be directly related to the mean slope of the surface. The interfacial shear strength increases almost linearly with the mean slope and was also found to increase with an increase in the 2D surface roughness parameter, R(a). Besides the surface roughness, the design of the implant, the bone anatomy and the bone quality were shown to influence the interfacial shear strength. The Global biomechanical model can be used as a tool for optimizing the implant design and the surface topography to obtain high anchoring strength.     

Jaw musculature during the dawn of turtle evolution

Using a new approach to study muscle anatomy in vertebrates, the fully differentiated jaw musculature of 42 turtle species was studied and character mappings were performed. Soft tissue arrangements were correlated to the temporal openings (emarginations) of the skull and the trochlearis system of the jaw apparatus among turtle taxa. When compared to the cranial anatomy of stem Testudines, most characters detected as diagnostic of particular extant groups have to be considered as being evolved first within Testudines. Hence, jaw muscle anatomy of extant turtles is difficult to compare to that of other reptilian taxa. Moreover, the high number of apomorphic character changes speaks for a divergating turtle and saurian morphotype of jaw musculature, which could indicate either a position of turtles outside of Sauria or a highly derived, undetectable origin within that group. In general, a low direct correlation of most soft and hard tissue characters was detected. This finding could imply that both character complexes are more integrated to each other driven by functional morphology; i.e., the composition of muscle fibre types. That condition highlights the difficulty in using gross anatomy of jaw muscle characters to interpret temporal bone arrangements among amniotes in general.     

Reduction of Metal Artifact in Single Photon-Counting Computed Tomography by Spectral-Driven Iterative Reconstruction Technique

PurposeThe exciting prospect of Spectral CT (SCT) using photon-counting detectors (PCD) will lead to new techniques in computed tomography (CT) that take advantage of the additional spectral information provided. We introduce a method to reduce metal artifact in X-ray tomography by incorporating knowledge obtained from SCT into a statistical iterative reconstruction scheme. We call our method Spectral-driven Iterative Reconstruction (SPIR).MethodThe proposed algorithm consists of two main components: material decomposition and penalized maximum likelihood iterative reconstruction. In this study, the spectral data acquisitions with an energy-resolving PCD were simulated using a Monte-Carlo simulator based on EGSnrc C++ class library. A jaw phantom with a dental implant made of gold was used as an object in this study. A total of three dental implant shapes were simulated separately to test the influence of prior knowledge on the overall performance of the algorithm. The generated projection data was first decomposed into three basis functions: photoelectric absorption, Compton scattering and attenuation of gold. A pseudo-monochromatic sinogram was calculated and used as input in the reconstruction, while the spatial information of the gold implant was used as a prior. The results from the algorithm were assessed and benchmarked with state-of-the-art reconstruction methods.ResultsDecomposition results illustrate that gold implant of any shape can be distinguished from other components of the phantom. Additionally, the result from the penalized maximum likelihood iterative reconstruction shows that artifacts are significantly reduced in SPIR reconstructed slices in comparison to other known techniques, while at the same time details around the implant are preserved. Quantitatively, the SPIR algorithm best reflects the true attenuation value in comparison to other algorithms.ConclusionIt is demonstrated that the combination of the additional information from Spectral CT and statistical reconstruction can significantly improve image quality, especially streaking artifacts caused by the presence of materials with high atomic numbers.     

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.