流体树脂应用于恒磨牙预防性充填术3年效果评价

目的探讨光固化流体树脂对年轻恒磨牙窝沟龋预防性充填治疗的疗效。方法对56例7～14岁患儿两侧同名磨牙分别采用两种不同的预防性树脂充填方法。试验组:112颗面窝沟龋在磨除龋坏牙体组织后联用后牙复合树脂与流体树脂对龋坏部位和未龋坏窝沟区域进行预防性充填治疗。对照组:112颗面窝沟龋在磨除龋坏牙体组织后采用传统窝沟封闭剂加后牙复合树脂,评价两组3个月、1年、3年的保留成功率。结果随访3年后发现采用Wave Flow流动复合树脂加后牙复合树脂进行预防性树脂充填治疗,充填成功率高达87.5%,对照组仅为67.7%,两组成功率比较具有非常显著性差异。结论光固化流体树脂加后牙复合树脂对年轻恒磨牙的窝沟龋治疗疗效确切,值得临床推广应用。     

氟化物涂膜与窝沟封闭术或预防性树脂充填联合使用预防第一恒磨牙龋的临床效果评价

目的： 探讨氟化物涂膜与窝沟封闭术或预防性树脂充填联合使用预防年轻第一恒磨牙龋病的临床效果。方法： 选取2015年2月—2016年1月在景德镇市第二人民医院进行口腔健康检查的90例儿童(6~8岁)300颗未成洞可疑龋的第一恒磨牙作为研究对象,随机分为A、B、C、D和E组。A组行窝沟封闭术;B组行预防性树脂充填术;C组行0.5%氟化物涂膜联合窝沟封闭术;D组行0.5%氟化物涂膜联合预防性树脂充填术;E组为对照组,单纯行日常刷牙护理。治疗后6、12、18个月复诊,观察各组儿童患龋比例及A、B、C、D组儿童窝沟封闭剂或树脂充填材料保留情况,采用SPSS21.0软件包对数据进行统计学分析。结果： 各组儿童在术后6、12个月时,A、B、C、D组儿童窝沟封闭剂或树脂充填材料保留率和患龋比例差异均无统计学意义（P>0.05）。术后18个月时,E组儿童患龋比例显著高于A、B、C、D组;A组与C组、B组与D组比较,差异有统计学意义（P<0.01）;A、B组儿童龋齿发生率较高,窝沟封闭剂或树脂充填材料保留率显著低于C、D组,差异均有统计学意义（P<0.05）。结论： 对年轻恒磨牙未成洞可疑龋采用氟化物涂膜联合窝沟封闭术或单独窝沟封闭术预防龋病有一定效果,但氟化物涂膜联合预防性树脂充填防龋效果更优。     

Dyract flow流动复合体充填窝沟的临床观察

目的评价Dyract flow流动复合体应用于预防性充填的临床效果。方法6～17岁患者136例408颗牙面窝沟龋,分为3组,每组136颗牙,每例中随机选择1颗患牙纳入流动复合体组,另2颗对侧同名牙或邻牙分别纳入复合树脂组和玻璃离子组。去除龋损后,流动复合体组使用Dyract flow流动复合体对龋损部位的窝洞充填,对深窝沟区域做预防性封闭充填治疗,复合树脂组和玻璃离子组的窝沟龋分别行光固化复合树脂或玻璃离子充填,并对深窝沟涂窝沟封闭剂。结果2年内3组充填材料保留率差异无统计学意义（P〉0.05）;经3年观察,Dyract flow流动复合体充填材料保留率较高,继发龋发生率较低,3组比较差异有统计学意义（P〈0.05）。结论Dyract flow流动复合体可作为窝沟龋的窝洞充填及深窝沟预防性封闭充填材料。     

儿童恒磨牙早期窝沟龋3种充填方法临床疗效比较

目的：观察光固化流体树脂、光固化复合树脂和窝沟封闭剂充填儿童恒磨牙早期窝沟龋的临床疗效。方法：分别用光固化流体树脂、光固化复合树脂和窝沟封闭剂充填儿童恒磨牙窝沟龋并随访观察疗效。结果：光固化流体树脂、光固化复合树脂和窝沟封闭剂3组充填后1年的充填物完全保留率分别为95．O％、91．7％和83．3％,三者比较差异无统计学意义。充填后2年光固化流体树脂、光固化复合树脂和窝沟封闭剂3组的充填物完全保留率分别为89．8％、75．4％和70．7％,光固化流体树脂的完全保留率高于光固化复合树脂组和窝沟封闭剂组,差异有统计学意义（P〈0．05）。结论：光固化流体树脂是一种较好的年轻恒牙早期窝沟龋充填材料,值得在临床推广应用。     

3种复合树脂充填Ⅴ类洞的微渗漏比较研究

目的:比较义获嘉N Ceram纳米瓷化树脂、N Flow流动树脂及Bulk Fill 三次方大块充填树脂充填上颌前磨牙Ⅴ类洞后树脂充填体边缘的微渗漏情况,评估3种不同复合树脂的抗微渗漏性能,寻找较好的充填V类洞的复合树脂材料.方法:选取牙体完整、健康的人离体前磨牙66颗,随机分为3组(n=22).所有样本牙在颊侧颈部制备标准V类箱状洞型(长4 mm、宽3 mm、深2 mm).3组试验牙经选择性釉质酸蚀自黏结后,分别使用N Ceram纳米瓷化树脂(A组)、N Flow流动树脂(B组)及Bulk Fill三次方大块充填树脂(C组)进行充填.充填完成后,3组试验牙均行弱光启动固化,打磨抛光.将3组样本进行1500个周期的冷热循环,2％亚甲基蓝浸泡染色7d,然后沿牙体颊舌向切片.每组随机选取2颗样本牙,在扫描电镜下观察牙体-充填体交界面的密合程度;其余60颗样本牙在体视显微镜下(×40)观察剖面充填体的微渗漏情况.采用Spot Advanced软件测量微渗漏深度,并根据0～3分分别给(牙合)、龈壁微渗漏程度评分.采用SPSS17.0软件包对各组的微渗漏深度分别进行Kruskal-Wallis秩和检验和Mann-Whitney检验.结果:义获嘉Bulk Fill组树脂在3组中龈壁的微渗漏最小,且与另外2组相比有显著差异,N Ceran纳米树脂组与N Flow流动树脂组龈壁的微渗漏均较高(P＜0.05);3组复合树脂材料(牙合)壁的微渗漏无显著差异(P＞0.05);3组树脂(牙合)壁的微渗漏值均比龈壁小且差异显著(P＜0.05).结论:3组树脂在(牙合)壁的微渗漏值无显著差异.义获嘉Bulk Fill组树脂充填V类洞时.在3组中龈壁的微渗漏最小,且与另外2种树脂之间有显著差异.     

免冲洗酸蚀复合体窝沟封闭系统的实验研究

目的比较免冲洗酸蚀复合体窝沟封闭系统和传统磷酸酸蚀窝沟封闭系统在恒牙应用时的封闭和微渗漏情况。方法16颗新鲜拔除的第三磨牙分成4组。Ⅰ组应用免冲洗酸、粘接剂Prime & bond NT和复合体窝沟封闭系统,Ⅱ组采用磷酸和Resin树脂窝沟封闭系统,Ⅲ组采用磷酸和复合体窝沟封闭剂,Ⅳ组采用免冲洗酸、粘接剂Prime & bond NT和Resin树脂窝沟封闭剂。应用硝酸银浸染法和实体显微镜检查微渗漏情况,扫描电镜观察窝沟封闭情况。结果4组牙齿都存在微渗漏。Ⅰ、Ⅳ组微渗漏比率均高于Ⅱ组（ P<0.01）;Ⅰ组和Ⅳ组、Ⅱ组和Ⅲ组的微渗漏比率也有统计学差异（ P<0.01）,Ⅰ组高于Ⅳ组,Ⅲ组高于Ⅱ组。扫描电镜观察发现采用磷酸酸蚀组可见树脂突,材料均匀;采用免冲洗酸蚀组基本上未见树脂突,材料之间裂隙大。多数样本的窝沟底部渗透较差。结论免冲洗酸蚀系统的微渗漏高于磷酸酸蚀系统,复合体封闭剂的微渗漏较高;磷酸酸蚀法有利于提高窝沟封闭剂的固位。     

4种根管充填技术的根尖微渗漏评价

目的采用葡萄糖定量微渗漏模型,评价不同根管充填技术封闭根尖的能力。方法选取72颗直的单根管牙,沿釉牙骨质界截冠,镍钛旋转器械进行冠向下法根管预备。随机分为4个实验组,每组15例,阳性和阴性对照组各6例。实验A组采用热牙胶垂直加压充填法,B组用固体核心载体充填法,C组用常温流动牙胶充填法,D组用冷牙胶侧压充填法进行根管充填。对照组只用牙胶尖充填,不用封闭剂。实验组和阳性对照组除根尖孔外均涂布2层指甲油,阴性对照组所有牙面均涂布2层指甲油。将牙齿连接于葡萄糖定量检测微渗漏模型,检测1、2、7、14、21、30d从冠方向根方渗漏的葡萄糖含量。通过渗漏葡萄糖的浓度（体积）推算微渗漏的大小。结果阴性对照组l～30d的渗漏值为0,阳性对照组则于ld即检测到较高浓度的葡萄糖。实验A、B、C组最大渗漏量均小于0.18μl/24h即无微渗漏发生,经秩和检验A、B、C3组间无显著差异（P〉0.05）。D组2d开始出现微渗漏,微渗漏量明显多于其它3组（P〈0.05）。结论 GuttaFlow常温流动牙胶法、热牙胶垂直加压充填法和固体核心载体充填法在观察期内,具有较好的根尖封闭能力。     

含氟封闭剂在乳磨牙早期窝沟龋预防性树脂充填术中的临床应用

目的：评价Helioseal F窝沟封闭剂结合预防性树脂充填术在儿童乳磨牙早期窝沟龋中的临床应用效果。方法：382颗患牙,随机分为两组。实验组192颗,应用Helioseal F窝沟封闭剂;对照组190颗,应用Helioseal窝沟封闭剂。两组病例均在预防性树脂充填术后在面进行窝沟封闭。进行1～3年随防观察。结果：经过3年随防,HeliosealF窝沟封闭剂3年完全保留率分别为：94.12%、86.49%、78.65%;龋病发生率分别为：0%、2.16%、3.93%;实验组龋病发生率显著低于对照组（P〈0.05）;封闭剂保留率与龋病发生率成负相关。结论：Helioseal F窝沟封闭剂结合预防性树脂充填术可有效防治儿童乳磨牙早期窝沟龋,其防龋效果优于传统窝沟封闭剂。     

二种复合体结合对窝沟龋预防性充填的效果研究

预防性树脂充填术是近年来发展起来的新型牙齿保存修复方法[1]。作者应用Dyract AP、flow2种复合体进行窝沟龋预防性充填术,取得了良好效果。1材料与方法1.1材料实验组采用Dyract AP、flow复合体(美国Dentsply公司),对照组采用Delton(可见光固化窝沟封闭剂。使用相配套的免冲洗     

树脂印章法与分层充填技术充填后边缘微渗漏的研究

目的比较树脂印章法美学修复充填与树脂分层充填术后边缘微渗漏的情况。方法选取符合纳入标准的40颗磨牙,于牙合面统一制备深达釉牙本质界以下约1 mm的Ⅰ类洞。随机分成A组20例和B组20例,A组采用印章充填技术进行后牙牙合面美学树脂充填,B组采用树脂分层充填并雕刻牙合面形态。两组充填样本经冷热循环实验后,分别置于2%亚甲基蓝溶液浸泡24 h,干燥后沿样本充填体正中颊舌向剖开,于体视显微镜下观察样本染料渗入情况,评价微渗漏程度,并进行统计学分析。结果染料渗入结果表明:A组(印章充填组)与B组(分层充填组)微渗漏程度差异具有统计学意义(P<0.05),印章组微渗漏低于分层充填组。结论印章法树脂充填术在保证相对美观的同时,可达到更好的边缘封闭,具有临床实用性。     

Clinical evaluation of a flowable resin composite and flowable compomer for preventive resin restorations

This clinical study evaluated the retention and caries protection of a flowable resin composite (Flow Line) and a flowable compomer (Dyract Flow) used in preventive resin restorations as compared to the conventional preventive resin technique which uses a resin composite (Brilliant) and a sealant (Concise). This study observed 205 permanent molars with small carious cavities less than 1.5 mm in width, which were obtained from 165 children aged 7 to 15 years. Flowable resin composite was used to treat 75 teeth, and 71 teeth were treated with flowable compomer in both cavities and caries-free fissures. For the control group, 59 teeth were treated with resin composite in cavities and sealant in caries-free fissures. The teeth were evaluated at 3, 6, 12, 18 and 24-month intervals. After three months, all 205 treated teeth were completely intact. After six months, 66 of the 71 teeth treated with flowable resin composite and 65 of the 70 teeth treated with flowable compomer were complete, compared to 57 of the 58 teeth treated with the conventional preventive resin technique. After 12 months, 60 of the 67 teeth treated with flowable resin composite and 61 of the 67 teeth treated with flowable compomer were complete, compared to 51 of the 55 teeth treated with the conventional preventive resin technique. After 18 months, 53 of the 61 teeth treated with flowable resin composite and 54 of the 62 teeth treated with flowable compomer were complete, compared to 47 of the 53 teeth treated with the conventional preventive resin technique. After 24 months, 49 of the 58 teeth treated with flowable resin composite and 45 of the 57 teeth treated with flowable compomer were complete, compared to 42 of the 52 teeth treated with the conventional preventive resin technique. There were no statistically significant differences in retention rates among all groups after 3, 6, 12, 18 or 24-months (p>0.05). One tooth treated with flowable resin composite and one tooth treated with flowable compomer developed caries after 18 and 24 months, respectively, resulting from partial loss at "caries-free fissures." Five teeth developed caries in the conventional preventive resin group; one after 12 months, two after 18 months and one after 24 months, due to loss at cavities. The final caries occurred after 24 months, resulting from partial loss at "caries-free fissures." The differences in caries development among the three groups were not statistically significant (p>0.05). This study suggested that flowable resin composite and flowable compomer could be used for preventive resin restorations. Meanwhile, a vigilant recall should be followed-up due to the risk of failure for flowable materials in "caries-free" fissures. The repair should be performed immediately, in case the preventive resin restoration develops a fracture or loss.     

The marginal seal of a flowable composite, an injectable resin modified glass ionomer and a compomer in primary molars--an in vitro study

The present study was carried out to compare the marginal microleakage of some newer materials viz. a flowable composite, an injectable resin modified glass-ionomer and a compomer in Class I cavities of 30 non carious primary molars. After 0.5% basic fuchsin dye penetration and sectioning, the teeth were studied under stereomicroscope. The results obtained revealed that flowable composite showed significantly lower microleakage (p<0.05) as compared to injectable resin-modified glass ionomer and compomer. However, no significant difference was observed when injectable resin modified glass-ionomer cement was compared to compomer. This concludes that flowable composite materials adhere better to the primary teeth than resin modified glass ionomer and compomer.     

The use of flowable composites as filled adhesives.

OBJECTIVE: The effect of filled adhesives on bonding resin composites to dentin has not been fully understood. Due to their filler content, filled adhesives may act as stress breakers. The aim of this in vitro study was to evaluate the use of flowable composites of different viscosities on bonding to enamel and dentin without the use of an intermediate bonding resin. MATERIALS AND METHODS: Enamel and dentin bond strengths of OptiBond FL, Syntac Classic, and EBS Multi combined either with their proprietary bonding agent or a flowable resin composite (Ultraseal XT Plus or Revolution) were measured. The tests were carried out with a microtensile device at a crosshead speed of 1mm/min after 24h of storage at 37 degrees C in water. Mean bond strengths were analyzed using the Wilcoxon test and multiple comparisons according to the Mann-Whitney U-test. The micro-morphology of corresponding resin-dentin interfaces of the same teeth were analyzed using SEM and TEM. RESULTS: The control groups with adhesive systems used as per manufacturers' protocol showed bond strengths of 38.9-41.1 MPa to enamel and 28.8-33.4 MPa to dentin. With respect to bond strength to etched enamel, only Ultraseal XT Plus as bonding resin reached the level of the control groups. When used as bonding agents on dentin, both flowable composites produced lower microtensile bond strengths to etched and primed dentin than did the control groups. Micro-morphological analysis using SEM and TEM resulted in hybrid layer formation for both control and experimental groups. However, many areas of the resin-dentin interface showed insufficient penetration of the flowable composites at the top of the hybrid layer as well as numerous tubules obstructed by filler particles. CONCLUSIONS: The flowable composites tested in this study should not be used to replace bonding agents. Flowable composites of thinner viscosity, such as Ultraseal XT Plus, may bond to enamel adequately without the requirement of an intermediate bonding resin.     

粘接托槽牙面流动复合树脂封闭层抗磨耗的实验研究

目的 观察流动复合树脂表面封闭层的耐磨性及其在提高粘接托槽牙面抗磨耗性能方面的作用.方法 40颗离体前磨牙随机分为未脱矿组、自酸蚀组、直接脱矿组、表面封闭后脱矿组,每组10颗.恒温水浴及冷热循环后,直接脱矿组、表面封闭后脱矿组置0.1M的乳酸胶脱矿48h,将4组离体前磨牙制成试件,牙刷磨耗31000次,扫描电镜观察颊面牙釉质结构及封闭层改变情况.结果 磨耗后,未脱矿组牙面未见刷痕;自酸蚀组、直接脱矿组牙面刷痕较深;表面封闭后脱矿组表面封闭层仍保留在牙面;流动复合树脂表面封闭层磨耗前、后的平均厚度（μm）是167.58±6.38、140.93±7.88,平均磨耗量（μm）是26.85±4.48,经配对t检验,磨耗前、后流动复合树脂表面封闭层厚度差异有统计学意义.结论 牙刷磨耗可磨去部分流动复合树脂,但不能去除流动复合树脂表面封闭层;表面封闭法能够提高粘接托槽牙面抗磨耗性能.     

Shear bond strength of new self-adhesive flowable composite resins

Recently, new self-adhesive flowable composite resin systems have been introduced to the market. These new composite resin systems reportedly bond to dentin and enamel without the application of an adhesive bonding agent. The purpose of this study was to evaluate the shear bond strength to enamel of two new self-adhesive flowable composites with and without the use of an etch-and-rinse bonding agent. The new self-adhesive flowable composites had significantly lower bond strengths to enamel compared to a traditional adhesively bonded flowable composite. Both self-adhesive flowable composites had a significant increase in bond strength to enamel with the use of a phosphoric acid-etch and adhesive bonding agent.     

Composite restorations: influence of flowable and self-curing resin composite linings on microleakage in vitro

This in vitro study evaluated the microleakage at enamel (occlusal) and dentin (gingival) margins of MOD resin composite restorations made with different incremental insertion techniques. MOD cavities were prepared on 60 extracted human molars with the proximal margins placed 1 mm below the cemento-enamel junction. All teeth were acid-etched and treated with One-Step adhesive, then restored with a hybrid resin composite (Renew) with and without a flowable composite (AEliteflo) or a self-curing composite (Bisfil 2B) as the first increment in the proximal boxes. The time of placement of the second increment in relation to curing of the first increment was also varied. After polishing, the teeth were soaked in 0.5% basic fuchsin for 24 hours, sectioned and evaluated for dye penetration. None of the restorative techniques prevented microleakage at the enamel and dentin margins. However, microleakage at dentin margins were significantly reduced by the use of a flowable composite as the first increment in the proximal boxes. Time of placement in relation to curing had no influence on microleakage. Microleakage was lower at enamel margins than at dentin margins; however, besides microleakage at the enamel-restoration interface, 37 of the 60 restored teeth (62%) displayed at least one white line in enamel adjacent to the composite restoration.     

流动树脂垫衬联合高强度流动树脂在牙邻面洞修复中的效果分析

目的 探讨流动树脂垫衬联合高强度流动树脂应用于牙邻面洞修复中的效果.方法 选择2018年6月至2019年6月我院收治的牙邻面洞修复患者86例(共86个患牙),按随机数字表法分为两组,各43例.对照组给予夹层修复技术(三明治技术),玻璃离子粘固剂与复合树脂的联合修复;实验组给予流动树脂垫衬联合高强度流动树脂修复.对比两组...     

Radiopacity of compomers, flowable and conventional resin composites for posterior restorations.

The objective of this study was to densitometrically determine the relative radiopacity (aluminum [Al]-equivalent values) of dentin, enamel, and 20 resin composite materials currently used for posterior restorations. Specimens 5 mm in diameter and 2 mm thick were fabricated from 20 materials (n = 7) for a total of 140 specimens. Human molars were longitudinally sectioned 2.0 mm thick to include both enamel and dentin. The optical densities of enamel, dentin, restorative materials, lead, and aluminum step wedge were obtained from radiographic images, using a transmission photodensitometer. The Al equivalent (mm) for each material was calculated from the linear regression equation of the log of normalized optical density and Al mm thickness obtained from the step wedge. A linear regression of the logarithm of normalized optical density and Al mm thickness was plotted (r2 = 0.9953), and the relative radiopacities, expressed as equivalent thickness of Al, were ranked ordinally. All materials tested, with the exception of an unfilled resin adhesive, complied with ISO Standard 4049, being at least as radiopaque as a 2.0 mm thickness of 99.6% pure Al. Four of six flowable composites had radiopacity values that fell between that of dentin and enamel, while two materials were more radiopaque than enamel. The three compomers tested had radiopacities greater than enamel. In addition, all traditional light- and chemical-cure resin composite materials tested were more radiopaque than enamel. All materials tested, with the exception of one adhesive resin, were at least as radiopaque as dentin and complied with ISO Standard 4049. Clinicians should be able to distinguish these restorative materials radiographically from recurrent decay, voids, gaps, or other defects that lead to clinical failure. Utilization of materials ranked more radiopaque than enamel would enable clinicians to distinguish the restorative material from tooth structure.     

The effect of flowable resin composite on microleakage in class V cavities

This in vitro study investigated the microleakage of flowable resin composite as a restorative material and as a liner (either light cured separately or co-cured with hybrid resin composite) in Class V cavities. A light-cured hybrid resin composite was used as a control. Twenty extracted human premolars were prepared with standardized Class V cavity outlines on the buccal and lingual surfaces. The occlusal margin of the cavities was on enamel and the gingival margin was on dentin. One bottle adhesive system (Single Bond) was used after etching enamel and dentin with 34.5% phosphoric acid for 15 seconds. The cavities were randomly divided into four groups of 10 each and restored according to the manufacturers' instructions: Group I-Hybrid resin composite (Z100); Group II-Flowable resin composite (Filtek Flow); Group III-Flowable resin composite (Filtek Flow)+Hybrid resin composite (Z100); light cured separately; Group IV-Flowable resin composite (Filtek Flow)+Hybrid resin composite (Z100); co-cured. The samples were thermocycled 200 times with a 30-second dwell time. They were then immersed in a 0.5% basic fuchsin solution for 24 hours, sectioned and analyzed by stereomicroscopy. The degree of dye penetration was recorded and analyzed with the Kruskal-Wallis and Mann-Whitney U tests. The results of this study indicate that there was no leakage at the occlusal margin for either restoration. Statistically significant differences were found among the groups at the gingival margin. No statistically significant difference was observed between the occlusal and gingival margins except in Group IV. The combination of flowable resin composite and hybrid composite light cured separately yielded the best result in this study. The most leakage was observed when this combination was co-cured. The resistance to microleakage of flowable resin composite as a restorative material is similar to that of hybrid resin composite.     

Influence of flowable liner and margin location on microleakage of conventional and packable class II resin composites

This in vitro study evaluated gingival wall microleakage in packable and microhybrid conventional composite restorations with and without a flowable composite liner. Each group was evaluated with gingival margins situated in both enamel and cementum/dentin. Two hundred and forty Class II cavities were prepared in extracted third molars, half with gingival margins in enamel and half with margins in dentin/cementum. In groups of 30, restoration was undertaken with packable alone (3M Filtek P60), conventional alone (3M Z250), packable plus flowable liner (3M Filtek Flow) and conventional plus flowable liner. All used 37% phosphoric acid etch and Scotchbond 1 (3M) as the bonding system. After restoration, the teeth were thermocycled (between 5 degrees C, 37 degrees C and 60 degrees C) 1,500 times, soaked in 0.1% methylene blue, sectioned and microleakage from the gingival margin scored. Statistical analysis was performed using Kruskal Wallis and Mann-Whitney U tests. There was no significant difference between systems in terms of leakage scores when gingival margins were situated in enamel (p=0.70). All restorations with margins in cementum/dentin leaked significantly more than those with margins in enamel (p<0.001). There was no significant difference between leakage scores of 3M Z250 and Filtek P60 with cementum/dentin gingival margins (p=0.68). Use of a flowable composite liner (3M Filtek Flow) against cementum/dentin was associated with increased microleakage (p<0.001). In this study, leakage scores suggest that gingival margins should be placed in enamel. The conventional and packable resin composites tested were not associated with differences in microleakage. Leakage data do not support the use of flowable resin composite linings in Class II resin composite restorations.