四种光固化复合树脂修复物边缘微渗漏的体外试验研究

目的:比较4种光固化充填材料修复体边缘微渗漏.方法:在新鲜拔除的40个人前磨牙的颊侧牙颈部制洞,将牙齿分为4组,每组10个.分别充填4种修复材料Restorative Z-350、Z-100(3M),Chafisma(Dentsply),Durafill(Kulzer)经冷热交替试验(4～60℃,循环600次),采用10 g/L碱性品红染料渗入法,在体视显微镜下观察修复体与牙体洞壁间边缘微渗漏.结果:4种材料中3M-Z350微渗漏最小,Durafill最大,DurafiU与其他3组相比有显著性差异(P＜0.05);3M-Z100和Chrisma无显著性差异(P＞0.05);3MZ350与其他3组相比有显著性差异(P＜0.01).结论:3M-Z350可能是临床修复牙体缺损的较好材料.     

牙齿荧光的研究及应用

荧光是天然牙的基本特性之一,也是影响修复体和天然牙颜色一致性的一个因素。随着对修复体的美学要求越来越高,修复体荧光特性的重视程度也越来越高。本文对牙齿荧光的研究背景、荧光机制、一般特点及其在口腔领域中的应用作一综述。     

儿童后牙牙体大面积缺损2种修复治疗的临床研究

目的：探讨儿童后牙牙体大面积缺损不同修复治疗的临床效果。方法：临床选择98例患儿后牙大面积缺损112颗患牙，随机分成实验组和对照组，作铸瓷嵌体修复或光固化复合树脂充填修复，并经1～2年临床疗效的追踪观察。结果：用铸瓷嵌体修复的病例成功率为80．5％，而采用树脂充填修复的成功率为56.8％。结论：在儿童大面积牙体缺损中，铸瓷嵌体修复技术有一定的临床应用价值可以推广，但制作中应注意适应证的选择，掌握操作要点，以提高成功率。     

The effect of curing with plasma light on the shrinkage of dental restorative materials

Commercially available light activated dental composites were used in this study to compare the shrinkage following curing with plasma light (Apollo95E, DMDS) and a convention halogen dental curing light (Prismetics Lite II, Dentsply). Polymerization shrinkage was determined by measuring the strain in one dimension by means of a contacting transducer. The percentage linear shrinkage were: Spectrum H = 1.84 + 0.31, P = 1.49 + 0.35*; Ana aesthetic H = 2.04 + 0.38, P = 1.85 + 0.27; Esthet.x H = 1.66 + 0.28, P = 1.69 + 0.25; Dyract AP H = 2.39 + 0.33, P = 2.18 + 0.35*; Apollo Restore H = 1.88 + 0.36, P = 1.42 + 0.33*; Surefil H = 0.88 + 0.28, P = 0.99 + 0.30 where * = significantly different, t-test at P < 0.05. The results suggested that there was less shrinkage when curing some, but not all, materials using the plasma light, although this could be attributed to a reduced level of polymerization.     

不同固化方式对封闭剂性能的影响

考察光固化、化学固化两种固化方式对封闭剂性能的影响。从粘结性能看，粘度值相近，树脂突长度无显著差异，但抗剪粘结强度光固化优于化学固化。在机械性能上，自制材料表面硬度、径向抗张强度光固化高于化学固化，在抗压强度上两者差异不大（Ｐ＞０．０５），但Ｃｏｎｃｉｓｅ材料结果与此相反，原因有待进一步研究，吸水性和磨耗率都是光固化小。总体评价，光固化实验室性能优于化学固化。     

A scanning electron microscope study of dentinal tubule continuity in monkey tooth sections

Abstract The American Dental Association (ADA) and Federation Dentaire Internationale (FDI) specifications for the biological evaluation of dental materials in experimental Cavities in dentine require that sections permit dentinal tubules to be followed from cavity floor to pulp lumen. The aim of this study was to investigate this requirement in the specification. Twenty hematoxylin and eosin stained sections of vervet monkey incisor teeth satisfying the ADA and FDI specifications were selected. Adjacent unstained sections of the same specimens were prepared for scanning electron microscopy, and a low power photomicrograph was taken of the dentine between the cavity floor and pulp for each specimen. Two areas on each photomicrograph were selected using a superimposed grid and random number table and this area was re-photographed at higher magnification on the specimen. A histometric analysis of the 40 SEM photomicrographs thus prepared showed that the dentinal tubules in 14 specimens were cut in cross-section, 14 were tangential and only 12 were longitudinal sections. None of die tubules examined in the high power photomicrographs was continuous. It is concluded that serial section evaluation of the area encompassing die entire cavity as well as a few sections before and beyond the cavity zone should be considered for inclusion in die specifications.     

应用结构光三维扫描技术重建面部软组织形态的初步研究

目的评价结构光三维扫描技术对面部软组织形态三维重建的可行性。方法应用基于格雷码和相位移动技术原理的结构光三维扫描技术，对1名志愿者面部及其面部石膏模型进行扫描，通过Imageware和Geomagic软件对获取的三维点云信息进行去噪、精简、平滑、三角化等数字化处理，重建面部和石膏模型的三维图像。比较三维重建图像测量项目结果和面部实际测量结果的差异。结果结构光三维扫描技术可完整重建志愿者面部的软组织形态，能较好地还原面部实际情况。结论基于格雷码和相位移动技术原理的结构光三维扫描技术能准确地重建面部软组织形态，可为面部缺损的三维重建奠定基础。     

Resorbable and nonresorbable hydroxyapatite granules as bone graft substitutes in rabbit cortical defects

Background: The use of various synthetic calcium phosphate compositions for the promotion of bone in bone defects is of potential interest because such materials may be tailor made and may bond to bone. There is yet an inadequate knowledge of the role of calcium phosphate composition and resorbability for the bone response. Purpose: The aim of the present study was to compare the ability of resorbable versus nonresorbable hydroxyapatite (HA) granules to promote new bone formation in cortical bone defects. Resorbable and nonresorbable HA granules, used as bone graft substitutes, were evaluated after 6 weeks and 3 months in the rabbit tibia. Circular defects (diameter 5.0 mm) were made in both tibias of 18 New Zealand white rabbits. The 36 defects were divided into three groups (six observations per group and time, respectively). The first group was augmented with resorbable HA granules, the second group was augmented with ceramic nonresorbable HA granules, and the third group was left without augmentation (control). The animals were killed after 6 weeks and 3 months, and the tissue was evaluated with light microscopic (LM) morphology and morphometry, scanning electron microscopy (SEM), and energy dispersive x‐ray analysis (EDX). Results: After 3 months LM morphometry revealed significantly more newly formed bone in the two HA augmented groups compared with that in the control. A close contact was found between both kinds of HA granules and new bone as viewed with light microscopy and SEM. A relatively slow degradation process was indicated by the small reduction of the total granule area in the cortical defects. However, LM observations showed a change of granule form. Pilot experiments using SEM‐EDX indicate that Ca and P contents had decreased in the resorbable HA granules between 6 weeks and 3 months. Further, a higher content of Ca and P was found in the newly formed bone close to granules, in comparison with more distant newly formed bone. Conclusions: Our results suggest that both resorbable and nonresorbable HA granules promote new bone formation in rabbit cortical defects, which does not occur in control defects.     

SHEAR BOND STRENGTH OF METALLIC BRACKETS PHOTO-ACTIVATED WITH LIGHT-EMITTING DIODE (LED) AT DIFFERENT EXPOSURE TIMES

The purpose of this study was to compare the shear bond strength of orthodontic metallic brackets photo-activated with two different light-curing sources at different exposure times: halogen light (XL 1500, 3M ESPE) and LED light (Ortholux, 3M Unitek). Sixty bovine permanent lower incisors were inserted into PVC tubes containing plaster. The buccal surfaces were cleaned with pumice and water, and then etched with 37% phosphoric acid gel. The XT Primer bonding agent (3M Unitek) was applied to the enamel surfaces and the metallic pre-coated brackets (Transbond APC II system, 3M Unitek) were attached to upper central incisors. The teeth were randomly divided into four groups (n=15). In Group I (Control), halogen light was used for 40 seconds, while in Groups II, III, and IV were light-cured with LED light unit for 40, 10, and 5 seconds, respectively. The teeth were stored in distilled water at 37°C for 24 hours. The brackets were submitted to shear bond strength test in universal testing machine (Instron) at a crosshead speed of 0.5 mm/minute. Shear bond strength means (MPa) were 4.87 for Group I; 5.89 for Group II; 4.83 for Group III, and 4.39 for Group IV. Tukey''s test detected no statistically significant differences among the groups regarding the shear bond strength (p>0.05). Neither of the types of light-curing sources or exposure times influenced the shear bond strength of metallic brackets.     

脉冲Nd:YAG激光辅助极固宁脱敏剂治疗老年牙本质过敏症的临床研究

目的：研究脉冲Nd：YAG激光辅助极固宁脱敏剂治疗老年牙本质过敏症的临床效果。方法：实验组用脉冲Nd：YAG激光1W（30mJ／cm^2、15Hz）照射120sec后，涂擦极固宁脱敏剂3次;对照组强采用极固宁脱敏剂3次。结果：实验组即刻、3个月及6个月有效率分别为87．29％、81．36％和75．42％，对照组的有效率为79．09％、63．64％和52．73％。即刻两组差异无屁著性（P〉0．05），而3个月、6个月差异有显著性（P〈0．01）。结论：脉冲Nd：YAG激光辅助极固宁脱敏荆治疗老年牙本质过敏症是一种高效、作用持久、使用安全的方法。