Three-dimensional reconstruction studies and morphometric analysis of rudimental tooth primordia in the upper incisor region of the sheep (Ovis aries,Ruminantia)

The functional dentition of the domestic sheep lacks all upper incisors and the upper canines. Nevertheless, occurrence of a dental lamina and rudimental tooth primordia had been described in the upper incisor region of the sheep. The aim of this study was to describe temporo-spatial pattern of origin and regression of these rudimental tooth primordia by light microscopy, computer-aided three-dimensional reconstruction and morphometry of the dental epithelium. Transient existence of a dental lamina in the upper incisor region of the sheep and three epithelial thickenings on its deep mesenchymal margin has been observed at day of ontogeny (DO) 48-53. They could not been identified as full-value tooth primordia, because they did not induce differentiation of tooth mesenchyme, but they could represent last remnants of functional upper incisors in early ancestors of ruminants. Additionally, a large rudimental upper canine primordium near the sutura maxilloincisiva occurred at DO43, reached early cap stage at DO52 and started to regress at DO53. Thus, our findings showed a discrepancy between the embryonic and adult dental pattern in the sheep. Similar molecular mechanisms as described for diastemal tooth rudiments in rodents could be involved during regression of rudimental tooth primordia in the upper incisor region of the sheep.     

三维放疗计划优化技术减少头颈部癌放射性口干症

目的：观察三维放疗计划优化技术减少头颈部癌放射性口干症的效果。方法：对三类头颈部癌（肿瘤位中线、偏一侧、近中线偏一侧）按常规放疗和优化技术分别作三维放疗计划。放疗优化技术包括放射进路优化、多野、适形放疗和加楔形板。对患者的肿瘤、腮腺和脊髓作三维剂量分布和剂量一容积DVH直方图分析。20例头颈部癌放疗患者分成常规放疗组和新技术（优化）组行放射治疗，记录放疗前、放疗中、放疗后及随访期患者的口干症评分和全唾液量。结果：肿瘤位一侧及近中线偏一侧时，常规和新技术放疗时健侧腮腺放射剂量分别为51.8-64.3Gy和0.4-1.4Gy；肿瘤位中线时常规和新技术放疗腮腺放射剂量分别为51.8Gy和24.7Gy；放疗结束时，新技术组口干症发生率1/12（8.3％）。随访4-6月后降为0，放疗结束时常规放疗组口干症发生率7/8（87.5％），随访4-6月后为4/8（50％）。结论：三维放疗计划优化技术可以明显减少头颈部癌患者放疗后口干症的发生。     

口腔颌面部淋巴管畸形的VEGF-C和VEGFR-3表达

目的 :观察接受和未接受平阳霉素治疗的淋巴管畸形中VEGF -C和VEGFR - 3表达 ,探讨平阳霉素治疗淋巴管畸形机制。方法 :收集 2 0例接受平阳霉素治疗的淋巴管畸形标本及 10例未接受治疗的标本做组织学观察以及免疫组织化学研究 ,评价形态学变化并分析VEGF -C和VEGFR - 3表达是否存在差异。结果 :两组病变VEGF -C和VEGFR - 3表达有显著性差异 (P <0 .0 5 ) ,并且VEGF -C和VEGFR - 3表达有相关性。结论 :平阳霉素注射治疗淋巴管畸形的分子机制可能是通过抑制VEGF -C -VEGFR - 3系统的信号传导从而达到治疗淋巴管畸形的目的     

舌鳞状细胞癌淋巴管密度与淋巴转移的关系

目的 探讨舌鳞癌组织中淋巴管密度与鳞癌侵袭和转移的关系.方法 选择62例舌鳞癌标本,采用免疫组化SP法检测血管内皮生长因子受体-3(VEGFR-3)和血管内皮生长因子-D(VEGF-D)的表达.结果 62例舌鳞癌标本中有56例标本的VEGFR-3呈阳性表达,但功能性淋巴管主要分布在癌组织周围,癌间质中未见明显的成形淋巴管.舌鳞癌组织中淋巴管密度与舌鳞癌患者年龄、性别无关,而与舌鳞癌病理分级、临床分期和有无淋巴结状况密切相关(P＜0.05).VEGF-D在癌细胞胞质呈阳性表达,且随着VEGF-D表达增强,癌组织周围淋巴管密度亦明显增加.结论 VEGF-D和VEGFR-3途径可促进鳞癌淋巴管新生和淋巴转移.     

Eagle's综合征的诊断和治疗——附7例分析

茎突过长是一种较少见的解剖异常，偶而可伴随有口咽，头颈部的不适或疼痛，并被命名为Ｅａｇｌｅ＇ｓ综合征。本文对７例因茎突过长而致口腔、咽、颈部不适的患者，从发病原因、病理机制、临床表现和体征，诊断及治疗等各方面进行了回顾分析；总结了两种手术途径的适应征和优缺点。作者首次将３维ＣＴ重建成像技术用于Ｅａｇｌｅ＇ｓ综合征的诊断，认为与以前常用的Ｘ线检查方法相比，３维ＣＴ重建成像技术具有更为明显的优点     

三维点激光扫描仪的扫描可靠性研究

目的全面评价Roland LPX-1200三维点激光扫描仪的扫描可靠性，为临床研究提供参考。方法规则加工的仿牙齿样模具，使用Roland LPX 1200点激光扫描仪获得其数字化模型，通过比较不同起始位置的扫描结果，评价扫描仪的扫描可重复性；选择长，宽，高三维方向上65项测量项目，比较数字化模型测量与实物测量之间的差异，评价其扫描准确性。结果连续扫描以及改变扫描初始位置引起的扫描随机误差在0．02mm以内；数字化模型测量与实物测量之间的差值均数为0．0012±0．05mm，P〈0．05。结论扫描仪具有良好的可靠性，能满足正畸临床对模型测量精度的要求。     

槟榔碱诱导口腔角质形成细胞凋亡研究

目的:了解槟榔碱(arecoline)对体外培养的人口腔黏膜角质形成细胞(keratinocyte,KC)凋亡的影响。方法:不同浓度的槟榔碱以及在不同时间处理体外培养的KC,在荧光显微镜下观察KC凋亡形态学改变并计算凋亡百分率,用比色法检测Caspase-3活性的改变。结果:1)槟榔碱能以一定时间和浓度依赖方式诱导培养的KC发生凋亡,其细胞凋亡率较正常对照组明显增高(P<0.05)。2)槟榔碱作用KC,其Caspase-3活性较正常对照组明显增高(P<0.05)。结论:槟榔碱可诱导KC凋亡,Caspase-3可能参与了这一细胞凋亡过程的调控。KC凋亡异常可能是口腔黏膜下纤维性变的重要发病机理之一。     

Binding of Actinobacillus actinomycetemcomitans lipopolysaccharides to Peptostreptococcus micros stimulates tumor necrosis factor α production by macrophage‐like cells

Peptostreptococcus micros is a gram‐positive bacterium that has been associated with periodontitis and endodontic infections. In this study, we hypothesized that P. micros binds the immunomodulating component lipopolysaccharide derived from gram‐negative bacteria to increase its capacity to stimulate cytokine production by host cells. The ability of P. micros to bind Actinobacillus actinomycetemcomitans lipopolysaccharide was demonstrated by an enzyme‐linked immunosorbent assay and by immunoelectron microscopy. Pretreatment of P. micros cells with A. actinomycetemcomitans lipopolysaccharide was associated with a 49‐fold increase in tumor necrosis factor alpha production by human monocytic cells U937 differentiated into adherent macrophages, compared to the stimulation with untreated P. micros. This effect was suppressed by incorporating polymyxin B, a lipid A‐binding substance, during treatment of macrophage‐like cells with lipopolysaccharide‐coated P. micros cells. This is the first study reporting a binding interaction between lipopolysaccharide and a gram‐positive bacterium. This interaction represents a new mechanism that could promote the inflammatory response during periodontitis.     

Effects of transforming growth factor beta1 (TGFbeta-1) and dentin non-collagenous proteins (DNCP) on human embryonic ectomesenchymal cells in a three-dimensional culture system

Cranial neural crest-derived ectomesenchymal cells represent a population of pluripotent stem cells giving rise to many of the various oro-facial and dental tissues. The factors determining the terminal fate of these cells are still unclear. The potentiality of human embryonic ectomesenchymal cells from the first branchial arch have been investigated when isolated and grown in a three-dimensional (3D)-collagen gel culture system in the presence of dentin matrix-derived non-collagenous proteins (DNCP) and TGFbeta-1. Functional differentiation of cells showing some characteristics of odontoblast-like cells could be observed when the cells were cultured with DNCP+TGFbeta-1 or DNCP, however, only cytological differentiation was observed during culture with TGFbeta-1 alone. The characteristics of these cells was assessed by morphological appearance, expression of the odontoblast phenotype marker dentin sialophosphoprotein (DSPP), increased alkaline phosphatase levels and formation of mineralised nodules in vitro. The results indicate that these embryonic cells from the first branchial arch are capable of responding to the inductive stimulus of DNCP or DNCP+TGFbeta-1 when isolated and grown in the 3D collagen gel culture system. The capacity of the isolated cells to differentiate into mineralizing cells showing some characteristics of odontoblast-like cells under these growth conditions highlights the potential of such approaches for tissue engineering strategies for hard-tissue regeneration after injury.     

烤瓷固定基底桥CAD系统标准桥体数据库的研究

目的:建立烤瓷固定基底桥标准桥体三维图形数据库,为基底桥的计算机辅助设计提供基础数据。方法:在Surfacer10.5软件平台上,对国人标准牙冠进行编辑和修改,平缓后牙面和前牙舌面上过陡的沟、窝、尖、嵴,定量预留外部瓷层三维空间。结果:创建了28颗恒牙烤瓷固定基底桥标准桥体三维图形数据库,编辑完成的桥体表面光顺,结构平缓,预留的瓷层空间均匀,符合临床要求。结论:数据库中的标准桥体数据是烤瓷固定基底桥CAD的模板,为自主开发烤瓷固定基底桥CAD/CAM系统奠定了基础。