内眦韧带的应用解剖及组织学研究

目的　研究内眦韧带的分支、走行、附着及其组织学构成。方法　对 6例 12侧尸颅内眦韧带进行解剖观察及测量 ,对 8例 8侧尸颅内眦结构进行组织学切片 ,光镜下观察内眦韧带的纤维构成及内眦区精细构造之间的关系。结果　内眦韧带前支的长度为 7.6± 1.5mm ,最大宽为 4 .5± 0 .7mm ,最小宽为 2 .3± 0 .5mm ;后支长度为 8.0± 1.0mm ,宽度为 6 .4± 1.4mm ;上支长度为 6 .7± 1.5mm ,宽度为 4 .5± 1.1mm ;前支距鼻颌缝的距离为 2 .8±1.0mm ,距鼻额缝的距离为 7.8± 1.5mm ;双侧韧带附着处之间的距离为 13.1± 2 .3mm。结论　内眦韧带由三个分支构成 ,均附着于骨膜。它们主要成分为胶原纤维 ,弹性纤维含量较少。眼轮匝肌内眦区的深层纤维通过组织移行参与构成内眦韧带。     

140例维吾尔族百岁老人下颌骨体表测量的观察

目的：观察下颌骨体有无增龄变化及其相关因素。方法：对１４０例维吾尔族百岁老人采用对一侧下颌骨体表直接测量长度及高度，并进行统计学处理。结果：一侧下颌骨体表长度在８．５ｃｍ～１３．０ｃｍ，高度在１．５ｃｍ～５．０ｃｍ，青年组长度大于百岁组（Ｐ＜０．００１），男性组长、高度大于女性组（Ｐ＜０．０１），有牙颌组长高度大于无牙颌组（Ｐ＜０．０１），正常舌组下颌骨长度大于裂纹舌组（Ｐ＜０．０５），但高度无显著性差异（Ｐ＞０．０５）。结论：下颌骨长高度具有生理变化，同时年龄、性别、有无牙列亦有影响，裂纹舌可能与下颌骨缩小有关。百岁老人有下颌骨体增龄表现     

Effect of finish line variants on marginal accuracy and fracture strength of ceramic optimized polymer/fiber-reinforced composite crowns

STATEMENT OF PROBLEM: Ceramic optimized polymer (Ceromer)/fiber-reinforced composite (FRC) crowns have been promoted as alternatives to conventional crowns. However, little is known regarding the ideal tooth preparation for this type of crown. PURPOSE: This in vitro study evaluated the marginal adaptation and fracture strength of ceromer/FRC crowns with respect to the various types of finish lines. MATERIAL AND METHODS: Four metal dies with different finish lines (0.9-mm chamfer, 1.2-mm chamfer, 1.2-mm rounded shoulder, and 1.2-mm shoulder) were prepared. Forty (10 for each finish line) Targis/Vectris crowns were fabricated on duplicated base metal alloy dies. The restorations were stereoscopically evaluated at 56 points along the entire circumferential margin for measuring the margin adaptation before and after cementation with a resin luting agent. The specimens were then compressively loaded to failure using a universal testing machine. The marginal adaptation (microm) was analyzed with the Kruskal-Wallis test and post-hoc Dunnett test (alpha=.05). The fracture load (N) was analyzed with a 1-way analysis of the variance and the Scheffe adjustment (alpha=.05). The fractured surfaces of the crowns were examined with a scanning electron microscope to determine the mode of fracture. RESULTS: The marginal adaptation of crowns with a shoulder finish line was significantly better than crowns with a chamfer finish line before and after cementation (P<.001). The increased marginal gap after cementation was the lowest in the 1.2-mm rounded shoulder group. The fracture strength of the crowns with the 0.9-mm chamfer and crowns with 1.2-mm chamfer was significantly greater than those of the crowns with the 1.2-mm shoulder or rounded shoulder (P=.011, P=.049, respectively). The mean fracture load of all crowns, regardless of the finish line design, was 1646 N. The fractured surface of the crown revealed adhesive failure and 3 types of cohesive failure (fracture of the Targis and Vectris, Targis fracture with a crack in the Vectris layer, and crushing without fracture). CONCLUSION: The marginal gaps were greater for the chamfer finish line specimens than in the shoulder finish line specimens. However, the fracture strength of the chamfer finish line specimens was greater than that of the shoulder finish line specimens.     

弹性模量和初始应力对种植体骨界面应力分布影响的三维有限元分析

目的:分析种植体弹性模量与骨界面应力分布的关系。方法:用三维有限元的方法对不同弹性模量种植体在各种载荷下骨界面的应力大小和分布进行分析。结果:种植体周围界面骨组织应力强度随着材料弹性模量的增大而增大。结论:低弹性模量的钛合金材料作为种植材料时具有更好的生物力学相容性。初始应力在分析种植体骨界面应力分布时必须加以考虑。     

Simultaneous flapless implant placement and peri-implant defect correction: an experimental pilot study in dogs

BACKGROUND: Minimally invasive implant surgery allows clinicians to place implants in less time, without extensive flaps, and with less bleeding and postoperative discomfort. The purpose of this study was to evaluate a new surgical technique by which implants are inserted in a deficient alveolar ridge using a flapless technique simultaneously with a peri-implant defect correction that is performed using a subperiosteal tunneling procedure. METHODS: Bilateral, horizontal defects of the alveolar ridge were created in the mandibles of five mongrel dogs. After 3 months of healing, one implant was placed on each side of the mandible by a flapless procedure. The exposed threads of the implant on one side of the mandible were covered with a 1:1 autogenous bone/xenograft mixture using a subperiosteal tunneling technique. Four months later, biopsies of the implant sites were taken and prepared for ground sectioning and analysis. RESULTS: All implants were well osseointegrated with the host bone. All of the peri-implant defects at the test sites were covered with tissue that resembled bone. In all specimens, a mixture of bone, connective tissue, and residual bone particles was observed in the graft area. In the control sites, where no graft was used, none of the exposed threads on any implants were covered with new bone. CONCLUSION: This preliminary report indicates the potential use of a minimally invasive flapless technique as a substitute for a more invasive implant placement and ridge augmentation procedure.     

低强度激光治疗颞下颌关节紊乱病的疗效评价

目的 评估低强度激光(LLLT)疗颞下颌关节痛的效果.方法 将颞下颌关节痛的患者按随机、双盲原则分为激光组(n=21)和对照组(n=21),每位患者均接受连续6d、每天1次的激光或假激光治疗.在治疗前、治疗后、治疗后1月、治疗后2月14个时点对患者的疼痛程度、功能状态进行测量和评估.结果 2组中疼痛视觉模拟评分(VAS...     

Brain activation patterns during unilateral premolar occlusion

Objective: To observe the characteristics of brain activation during unilateral premolar occlusion.

Methods: Functional magnetic resonance imaging was collected from 10 healthy volunteers during occlusion of the left first premolar (L1), left second premolar (L2), and right first premolar (R1). The brain activation patterns were analyzed, and the primary sensorimotor cortex, supplementary motor area, insula, thalamus, and prefrontal cortex were chosen as regions of interest.

Results: Single premolar occlusion activated the precentral gyrus, postcentral gyrus, cerebellum, thalamus, frontal lobe, hippocampus, cingulate gyrus, and parietal lobe. The brain areas showing activation during single premolar occlusion were similar to those activated by chewing. The activation pattern of L1 was more similar to that of L2 than R1. No significant left and right hemisphere differences in signal intensity were detected within the regions of interest.

Conclusion: Brain activation patterns from two ipsilateral premolars were more similar than the pattern from a contralateral premolar.     

胶囊粉对可见光固化复合树脂机械性能的影响

目的:改善光固化复合树脂的强度和抛光性能.方法:我们采用悬浮聚合法研制了微胶囊型复合填料粉(MCP),作为光固化改进型(VLC-Ⅱ型)复合树脂的填料.并对其性能进行了测试.结果:在复合树脂中加入15%的胶囊型填料粉,压缩强度可达232.1±9.1MPa,拉伸强度可达48.7±2.3MPa,70000次牙刷磨耗率为0.588%,表面粗糙度为2.8μm.结论:胶囊粉可以显著改善复合树脂的压缩强度,拉伸强度,磨耗及表面抛光性等机械性能.与其它同类产品比较,其机械性能、磨耗性能和表面抛光性能均较优越,且相差显著.     

Use of separate single-tooth implant restorations to replace two or more consecutive posterior teeth: a prospective cohort study for up to 1 year

PURPOSE

The aim of this study was to evaluate the periodontal and prosthodontic complications of multiple freestanding implants in the posterior jaws for up to 1 year of function.

MATERIALS AND METHODS

Eight patients received 20 implants posterior to canines. Two or more implants were consecutively inserted to each patient. Single crowns were delivered onto the implants. Marginal bone loss, implant mobility, probing depth, and screw loosening were examined to evaluate the clinical success of such restorations for maximum 1 year of functional loading.

RESULTS

All the implants performed well during the observation period. Neither periodontal nor prosthodontic complications were found except a slight porcelain chipping. While the marginal bone level was on average 0.09 mm lower around the implant after 6 months of loading, it was 0.15 mm higher after 1 year.

CONCLUSION

Within the limits of this investigation, separate single-tooth implant restorations to replace consecutive missing teeth may clinically function well in the posterior jaw.