脉冲Nd:YAG激光照射牙本质后对光固化树脂充填体边缘微渗漏的影响

目的研究脉冲Nd：YAG激光照射牙本质后对光固化树脂充填体边缘微渗漏的影响，以探讨脉冲Nd-YAG激光在龋病治疗中的临床应用意义。方法选用正畸要求拔除的正常双尖牙30颗，随机分为A。B，C三组，每组10颗，用高速裂钻备洞（洞长、宽为3mm；洞深为2mm），A组为对照组，常规酸蚀树脂充填；B，C两组分别用50mJ，10Hz和100mJ，10Hz的脉冲Nd：YAG激光能量照射窝洞牙本质壁30s后树脂充填，分别用体视显微镜和扫描电镜观察充填体边缘和洞壁结合情况。结果．体视显微镜下观察：A组的牙本质洞壁与光固化树脂充填体间染料渗入较多，着色较深；B、C组的牙本质洞壁与光固化树脂充填体间染料渗入较少，着色较浅。扫描电镜下观察：B、C组的牙本质洞壁与光固化树脂充填体间裂隙明显小于未经激光处理的对照组。结论脉冲Nd：YAG激光处理牙本质后进行光固化复合树脂充填，可以减少充填体微渗漏，有利于充填的成功．     

伢典化学机械去龋法的粘结性能研究

目的：利用健康离体牛牙,评价伢典对健康牙本质与复合树脂间剪切粘结强度的影响。方法：选取新鲜拔除的牛切牙28颗,磨除唇面釉质,暴露牙本质,分为4组,即空白对照组,酸蚀组,伢典处理组,伢典处理＋酸蚀组。分为不做预处理组,37%磷酸酸蚀组,伢典处理牙本质表面3min组,伢典处理牙本质表面3min后再用37%磷酸酸蚀处理组。在牙本质表面粘结形成直径5mm,高3mm的光固化树脂圆柱体。37℃水浴24h后,以1mm/min的加载速度进行剪切粘结强度测试。结果：伢典处理后的健康牙本质的剪切粘结强度大于不做预处理的健康牙本质。伢典处理不影响酸蚀效果。结论：伢典对复合树脂与健康牙本质间的粘结强度没有显著影响。     

BISCO复合材料与银汞合金的粘结——扫描电镜观察

目的为了观察BISCO复合材料处理窝洞壁对银汞合金充填体边缘密合性的影响方法采用健康人下颌智齿按一定要求制成牙本质洞实验组BISCO复合材料处理洞壁后在其未凝固之前立即充填银汞合金对照组洞壁未作特殊处理直接银充扫描电镜SEM观察充填体-BISCO复合材料-牙体界面形态并测量充填体边缘缝隙宽度结果实验组充填体边缘缝隙宽度明显小于对照组p<0.01结论BISCO复合材料与银汞合金间结合紧密可以改善充填体边缘密合性。     

复合树脂联合两种酸蚀粘结剂与乳牙釉质及牙本质的剪切粘结强度比较

目的:比较复合树脂联合全酸蚀和自酸蚀粘结剂与乳牙釉质及牙本质的剪切粘结强度。方法:收集新鲜拔除的滞留乳磨牙48个,随机分为4组,分别制备全酸蚀和自酸蚀粘结剂的釉质和牙本质试件,电子万能试验机测定各组剪切强度;体视显微镜下观察试件断面的破坏模式;扫描电镜观察粘结界面情况。结果:全酸蚀粘结剂组的釉质剪切强度明显高于牙本质剪切强度(P<0.05);自酸蚀粘结剂组釉质与牙本质剪切粘结强度无统计学差异(P>0.05);全酸蚀粘结剂组的釉质、牙本质剪切粘结强度均明显高于自酸蚀粘结剂组(P<0.05);体视显微镜及扫描电镜观察均显示,全酸蚀粘结剂与釉质和牙本质的粘结界面结合程度好于自酸蚀粘结剂。结论:全酸蚀粘结剂处理对乳牙釉质及牙本质的剪切粘结强度高于自酸蚀粘结剂。     

黏结剂直接盖髓体外实验研究

目的:采用器官培养模型方法,评价自酸蚀黏结剂直接盖髓后的牙髓反应.方法:取临床上因正畸拔除的健康完整新鲜前磨牙30个,随机分为3组,制备<牙合>面洞,机械露髓,分别用自酸蚀黏结剂Xeno Ⅲ和氢氧化钙Dycal盖髓,复合树脂充填窝洞,余1组不做任何处理作正常对照,然后将牙齿纵向切割成2mm厚的牙片,DMEM体外培养3、7、14 d,分别进行HE检测和免疫组化检测.结果:HE显示术后3 d各组均表现为成牙本质细胞排列紊乱、毛细血管扩张;术后7、14 d牙髓逐渐恢复正常,3组均无牙本质桥形成,对照组釉质、牙本质、牙髓呈有序结构.免疫组化结果显示:术后3 d两组成牙本质细胞、露髓孔下方部分牙髓组织中DSPP均呈阳性表达,7、14 d表达同正常对照组.结论:自酸蚀黏结剂Xeno Ⅲ和氢氧化钙在短期内对牙髓组织刺激反应相似.     

银汞合金粘结修复术的临床应用

1995年我院研制出EA-1型银汞合金粘结剂,并开始在牙体病科首先应用于临床,由专人负责进行,到1997-10止,共治疗患者158人次,212个牙。现将术后3年随访的疗效作一报道。1　临床资料1.1　病例选择残冠,牙体劈折缺损,龋坏面积较大等固位差的窝洞。1.2　材料来源酸蚀剂、EA-1型粘结剂:第四军医大学口腔医学院生产;银汞合金:上海齿科材料厂。1.3　操作方法1.3.1　去净龋,洞形略修正,磨改薄壁弱尖;1.3.2　窝洞牙本质和釉质涂酸蚀剂40s,清水冲洗,拭干窝洞;1.3.3　调拌粘结剂呈稠糊状,用小毛刷蘸适量的粘结剂均匀地涂布于酸蚀过的牙面上;1.3.4　立…     

"一滴棒"用于银汞合金粘结效果的扫描电镜研究

目的:观察“一滴棒”用做银汞合金粘结剂来处理窝洞壁,对银汞合金充填体与牙体粘结的影响。方法:采用因正畸需要拔除的健康人新鲜恒前磨牙,按要求制成牙本质洞。实验组:“一滴棒”粘结材料处理窝洞壁后(其中A组用压缩空气吹干-干粘结法,B组用脱脂棉球擦干-湿粘结法),均在粘结材料未凝固前立即充填新鲜调制的银汞合金;对照组:窝洞壁未作特殊处理,直接银汞合金充填。扫描电镜观察银汞合金充填体-“一滴棒”粘结材料-牙体界面的形态,并测量充填体边缘缝隙宽度和粘结剂厚度。结果:实验组充填体边缘缝隙平均宽度(A组4.82μm,B组为0)显著小于对照组(11.33μm)(P<0.05),2实验组间粘结剂平均厚度无明显差异(A组62.66μm,B组59.54μm)(P>0.05)。结论:“一滴棒”粘结材料用于银汞合金粘结可显著改善银汞合金充填体边缘密合性,干粘结和湿粘结法对粘结剂厚度无明显影响。     

2种黏结系统与3种牙体硬组织间黏结界面的超微结构研究

目的:比较第7代自酸蚀黏结剂Adper Easy One与两步法全酸蚀黏结剂Adper Singlebond2黏结处理复合树脂充填后的形态学超微结构。方法:在20颗离体人磨牙的颊、舌侧制备盒形单面洞(直径5 mm,洞深3 mm),牙根中1/3处切取表面根片(长5mm,宽3mm),分为2组,每组10个牙冠、10个根片。对2组牙冠的窝洞和根片分别应用黏结剂Adper Singlebond2、Adper Easy One,充填黏结复合树脂后,将其从中间纵向剖开,各得到20个试件。每组随机抽取牙冠部和牙根部各10个试件,进行5000次冷热循环,剩余试件泡于蒸馏水中,常温存放1个月,砂纸打磨抛光,固定脱水,真空干燥、喷金,扫描电镜下观察剖面充填物边缘的黏结情况。结果:扫描电镜显示,全酸蚀Adper Singlebond2黏结处理、常温放置和冷热循环后,牙釉质、牙本质和牙骨质与黏结剂黏结紧密。自酸蚀黏结系统Adper Easy One黏结处理,常温下牙釉质黏结偶见细小裂隙,牙本质和牙骨质与黏结剂结合良好。冷热循环后,牙釉质黏结疏松,可见明显裂缝,牙本质和牙骨质黏结良好。结论:扫描电镜超微观结构观察显示,Adper Singlebond2全酸蚀黏结剂对牙釉质的黏结优于Adper Easy One自酸蚀黏结剂,而对于牙本质和牙骨质效果无明显差别。     

三种一步法自酸蚀粘结剂对复合树脂粘结修复后微渗漏的影响

目的:探讨3种一步法自酸蚀粘结剂对复合树脂粘结修复后微渗漏的影响.方法:取正畸治疗拔除的正常前磨牙105个,在每个牙的颊侧颈部制备4 mm ×2 mm ×2.5 mm的窝洞后,随机分为A1组(磷酸预处理后自酸蚀Clearfil S3 Bond)、A2组(自酸蚀Clearfil S3 Bond)、B1组(磷酸预处理后自酸蚀Beautibond)、B2组(自酸蚀Beautibond)、C1组(磷酸预处理后自酸蚀Hybrid Coat)、C2组(自酸蚀Hybrid Coat)和D组(全酸蚀Prime&Bond NT).粘结和复合树脂充填后冷热循环处理;亚甲蓝溶液染色24h.然后将各牙沿颊舌向通过充填体中央纵行剖开,体视显微镜下观察充填体边缘的染色情况并进行分级;SEM观察粘结界面形貌.结果:A2、B2、C2组间微渗漏值比较P＞0.05,但均小于D组;A2、B2与D组相比P＜0.05;C2与D组比较P＞0.05.A1、B1、C1组间微渗漏值比较P＞0.05,但均小于D组(P＜0.05).A1与A2、B1与B2相比P＞0.05;而C1组微渗漏值小于C2组(P＜0.05).SEM观察显示,3种自酸蚀粘结剂均与牙体组织、树脂结合严密均匀.结论:3种一步法自酸蚀粘结剂边缘封闭性均良好,磷酸预处理釉质可减少Hybrid Coat自酸蚀粘结剂的微渗漏.     

几种市售商品充填材料密合度的实验研究

选用几种市售牙体充填复合树脂和玻璃离子水门汀充填Ⅴ类洞(龈壁由牙骨质和牙本质组成),采用染色法观察其边缘微漏的离体牙实验。发现不同充填材料存在不同程度的边缘微漏,酸处理洞缘可显著降低边缘微漏(P<0.05),窝洞的牙釉质壁渗漏显著低于牙骨质壁渗漏(P<0.01)。实验结果提示,充填材料的粘附性能,窝洞边缘的位置以及酸处理技术,都将影响牙体充填的治疗效果。     

Acid etching and composite resin restorations. A culturing and histologic study bacterial penetration

Abstract Class-V cavities were prepared on the buccal surfaces of homologous pairs of premolars in vivo. Composite resin restorations (Adaptic®) were performed using two different acid-etch techniques. All cavities were unlined. Four cavities were unetched and served as controls. In one series the enamel margins were etched and a non-composite intermediate resin was used before filling. In the second series the enamel surrounding the composite filling was etched after the insertion of the composite resin and coated with an UV-light polymerized resin (Nuva-Seal®). The results were evaluated using both histological and culturing techniques. Neither of the two etching techniques was effective in preventing marginal leakage and in growth of bacteria was found along the cavity walls. The cervical border of the Class-V cavity is considered a weak link for marginal leakage. Culturing revealed a bacterial flora resembling that of dental plaque.     

The initial gap around large composite restorations in vitro: the effect of etching enamel walls

Composite resin restorations in cavities are generally associated with the development of a contraction gap during the first minutes after insertion. Enamel-Bond-Concise composite restoration were placed on both approximal sides of extracted pre-molars. The cervical walls of all cavities extended beyond the enamel-cement junction. The enamel walls of one of the cavities in each tooth were acid-etched. The contraction gap was kept air-filled and open at the margin through the use of a special technique. Enamel Bond resin with a fluorescent additive was applied to occlusal and cervical margins of the restorations. The fluorescent resin was "passively" drawn into the gap. In unetched cavities, resin penetrated both cervical and occlusal gaps and some areas of the gap at the axial wall. In cavities with etched enamel, the penetration occurred only at the cervical wall. The distance of penetration from the cervical margin varied from 1 to 6.5 mm, and the width of the contraction gap filled with the fluorescent resin varied from 3.5 to 16 micron. Comparison of the width of the gap at the cervical wall in etched and unetched cavities suggested larger gaps for etched cavities. The method used offers a new technique for the measurement of the contraction gaps around composite resin restorations.     

Clinical performance of a self-etch adhesive in Class V restorations made with and without acid etching

OBJECTIVES: To evaluate the clinical performance of a self-etching adhesive in Class V carious lesions with and without acid etching procedures. METHODS: A total of 183 Class V carious cavities with incisal margins in enamel and gingival margins in cementum were selected and restored with Futurabond NR self-etch adhesive and resin composite Grandio. Restorations were made using three different techniques; after etching of the enamel, after etching the whole cavity for 20s and without acid etching (control). The restorations were evaluated at baseline, 1 and 2 years using USPHS criteria. RESULTS: No loss of restorations was recorded after 1 and 2 years for all the three restorative techniques. There was no significant difference between the baseline and 2-year results for any of the tested technique. However, restorations made after acid etching showed less marginal discoloration at the enamel margins. CONCLUSION: The clinical performance of Futurabond NR self-etch adhesive was excellent after 2 years. Acid etching of the enamel margin or the whole cavity did not improve the overall quality of the restorations, but displayed less marginal discoloration.     

Replica patterns on composite restorations performed in vivo with different acid-etch restorative procedures

243 experimental Class V restorations using a chemically cured composite resin were inserted in human third molars with the conventional acid-etch restorative procedure and eight modifications of this technique. The teeth were extracted after 4 months and, following demineralization, the filings were examined in SEM concerning their enamel and dentin replica patterns on the inner cavity faced surface. Results showed a significant correlation between the enamel replica patterns and the marginal adaptation of the restorations while the dentin replica patterns did not influence the in vivo adaptation. Furthermore it was found that the improved adaptation obtained by low viscous resin applied as an intermediary layer in etched cavities is due to fewer porosities in the restorative material interface with enamel and dentin. Beveling of preparations prevents stress-induced fractures of unsupported enamel prisms along the cavity periphery. Treatment of etched cavities with the surface active comonomer NPG-GMA increases the general interfacial contact between resin restoratives and cavity walls, and surface coating of finished and re-etched restorations fills up spaces created along cavity margins during the filling and finishing procedure.     

Replica patterns on composite restorations performed in vivo with different acid-etch restorative procedures

Abstract 243 experimental Class V restorations using a chemically cured composite resin were inserted in human third molars with the conventional acid-etch restorative procedure and eight modifications of this technique. The teeth were extracted after 4 months and, following demineralization, the fillings were examined in SEM concerning their enamel and dentin replica patterns on the inner cavity faced surface. Results showed a significant correlation between the enamel replica patterns and the marginal adaptation of the restorations while the dentin replica patterns did not influence the in vivo adaptation. Furthermore it was found that the improved adaptation obtained by low viscous resin applied as an intermediary layer in etched cavities is due to fewer porosities in the restorative material interface with enamel and dentin. Beveling of preparations prevents stress-induced fractures of unsupported enamel prisms along the cavity periphery. Treatment of etched cavities with the surface active comonomer NPG-GMA increases the general interfacial contact between resin restoratives and cavity walls, and surface coating of finished and re-etched restorations fills up spaces created along cavity margins during the filling and finishing procedure.     

A new experimental restoration model in man for studying enamel reactions

A new model of experimental restoration is suggested for testing the marginal imperfections of composite resin, for examining the surface morphology of composite restorations and of sound, etched and remineralized enamel. Enamel-dentine samples with standardized cavities and composite restorations were placed on lower removable partial dentures using the etching technique. After 12 and 28 days the specimens were examined in a scanning electron microscope (SEM), operated at 15 kV. After 12 days the examination of the conventional composite resin by SEM showed extremely rough structures. The use of the enamel etch techniques produces acceptable marginal conditions with tags and some minor gaps. Etching the enamel emphasizes its prismatic structure and reveals the typical pattern of demineralization, involving prism cores and the preferential dissolution of prism peripheries. After 12 days the SEM appearance of uncovered etched enamel suggested that incomplete remineralization had occurred. After 28 days the mineral recoating, which had progressed further, predominantly involved prism-orientated repair. The experimental model described here is more accurate, highly standardizable and easily accessible, compared with conventional clinical and replica techniques.     

Adaptation and microleakage of composite resin restorations

A bstract — The ability of composite resins to adapt to acid-etched enamel cavity walls is examined and microleakage which occurs around composite resin restorations placed in etched and unetched cavities is investigated.
The use of an unfilled resin layer prior to application of the composite resin optimized adaptation. Cavity walls for composite resin restorations should be etched. For the teeth investigated, a 2 minute etch produced a more reliable etch pattern on the enamel and less micro-leakage than a 1 minute etch.     

Marginal leakage with different composite restorative materials in vitro

In this preliminary study the degree of marginal leakage was assessed for different cavity designs using both ultra violet-curing and self-curing composite restorative materials and sealants. Butt joint restorations placed in etched and sealant primed cavities failed to prevent leakage. Both saucer-shaped and funnel-shaped cavities and cavities with rounded margins were able to prevent leakage when the restorations were bonded to etched and sealant primed peripheral enamel. Further, less than 1 mm of gingival enamel available for bonding seemed to be sufficient in most instances to prevent leakage.     

EFFECT OF ADDITIONAL ENAMEL ETCHING AND A FLOWABLE COMPOSITE TO THE INTERFACIAL INTEGRITY OF CLASS II ADHESIVE COMPOSITE RESTORATIONS

Objective : The purpose of this study was to evaluate microleakage of Class II composite restorations using a self‐etching adhesive system with additional enamel etching and/or a flowable resin composite material. Materials and Methods : Fifty standardized Class II cavities were prepared in the mesial and distal surfaces of extracted human third molars. All teeth were bonded with a self‐etching primer adhesive system (Clearfil® Liner Bond 2, Kuraray Co. Ltd., Osaka, Japan) according to the manufacturer's instructions and were restored with a resin composite (Clearfil® AP‐X, Kuraray Co. Ltd.). In the control group, only a self‐etching adhesive system was used. In the various experimental groups, the preparation surfaces were coated with a layer of flowable resin composite (Protect® Liner F, Kuraray Co. Ltd.) before the placement of resin composite, etched with 37% phosphoric acid (K‐Etchant®, Kkraray Co. Ltd.) before the application of the adhesive system, or treated with both of these options. In four groups of specimens, the preparation had a gingival margin in enamel. In a fifth group, the gingival margin was in dentin. All teeth were subjected to thermocycling, 300 cycles between 4°C and 60°C, and were sectioned in half through the restorations. Gaps or cracks at the resin‐tooth interfaces were observed directly using a laser scanning microscope and were recorded as percentages of the entire interface length. Results : Separate enamel etching with phosphoric acid did not improve the resin‐enamel seal produced by the self‐etching primer alone. Flowable resin composite produced gap‐free resin‐dentin interfaces but could not prevent cracks and gap formation at the resin‐enamel interface. Conclusions : Neither flowable resin composite nor enamel etching could prevent gap formation at enamel‐resin interfaces and crack formation in enamel walls when used with a self‐etching primer adhesive system. However, the flowable composite provided gap‐free resin‐dentin interfaces.     

Microleakage of composite restorations after acid or Er-YAG laser cavity treatments.

OBJECTIVES: The purpose of this study was to compare microleakage of Class V restorations following acid, laser or laser and acid treatment of cavity walls. METHODS: Standardized lingual and buccal Class V preparations were made in 18 human extracted third molars. The preparations were randomly assigned to three equal groups (n=12). Group 1: cavities were treated with 35% phosphoric acid. Group 2: cavities were irradiated with an Er-YAG laser at 2Hz and 250mJ on dentin and 300mJ on enamel, with water cooling. Group 3: cavities were irradiated with the laser before acid etching. Scotchbond 1 Adhesive System and Z100 resin composite were used for restorations. The specimens were stored in water for 24h at 37 degrees C and thermally cycled (500x) between 6-60 degrees C. After 24h immersion in 0.5% basic fuchsin, dye penetration was recorded according to an ordinal scale. Data were analysed using non-parametric statistical tests (Kruskal-Wallis and Mann-Whitney). RESULTS: On the occlusal walls, microleakage in acid etched cavities was significantly lower than that achieved after laser treatment (P<0.001) or after both treatments (P<0.05). On the gingival walls, no statistical differences were found. SIGNIFICANCE: Laser irradiation of enamel is not a valid alternative to acid-etching pretreatment for resin composite materials adhesion. Acid etching alone gave the lowest microleakage at the occlusal margin. No differences were found for microleakage on gingival wall, although lased dentin surfaces presented several characteristics that appear to be advantageous for bonding.