新型基质材料在降低光固化复合树脂体积收缩方面的研究进展

光固化复合树脂在口腔临床中应用广泛,但光固化过程中产生的体积收缩和收缩应力影响了临床修复效果。树脂基质作为复合树脂的主体成分,对树脂的性能有着重要影响,而树脂基质一般由主要单体和低粘度的稀释性单体聚合而成。研究人员试图通过改进树脂基质中的单体,降低复合树脂的体积收缩及收缩应力,增强机械性能,提高临床修复效果。该文就最近几年树脂基质单体的研究进展作简要综述。     

新型环氧树脂聚合体积收缩率及聚合收缩应力初探

目的 评价新型环氧树脂的聚合体积收缩率和聚合收缩应力,为其临床应用提供参考.方法 选用3种复合树脂材料:A组:丙烯酸酯树脂(XenoⅢ-TPH);B组:丙烯酸酯树脂(Clearfil SE bond-Clearfil Majesty Posterior);C组:新型环氧树脂(FiltekTM silorane adhesive-P90).3组复合树脂经光照固化后,用显微CT测量聚合体积收缩率,用万能材料实验机测试聚合收缩应力.结果 A、B和C组复合树脂的聚合体积收缩率分别为(3.38±0.17)％、(1.95±0.37)％和(1.05％±0.09)％;C组最小,与A、B组的差异均有统计学意义(P ＜0.001).A、B和C组复合树脂的聚合收缩应力分别为(3.04 ±0.26)、(3.49±0.46)和(1.54±0.15) MPa;C组最小,与A、B组的差异均有统计学意义(P＜0.001).结论 新型环氧树脂具有优良的低聚合收缩性能.     

软启动照射模式对复合树脂聚合收缩的影响

目的:测定不同光照强度的软启动照射模式下同一种复合树脂的聚合收缩率.方法:采用粘接片(bonded discs)法测定卡瑞斯玛光固化复合树脂(体积38.5 mm3,C值0.47)在不同照射模式(高普40s、高普20 s、高渐进、高脉冲、中普、中渐进、中脉冲、台阶1、台阶2、台阶3)照射3min的聚合收缩率.结果:3种台阶照射模式的聚合体积收缩率均显著大于其他照射模式(P＜0.05);高普20 s模式的聚合体积收缩率显著大于高渐进、高脉冲模式(P＜0.05),但与高普40s相比无显著差异(P＞0.05);中普、中渐、中脉冲照射模式间体积收缩率两两相比均无显著差异(P＞0.05);台阶1照射模式的体积收缩率显著大于台阶2和台阶3(P＜0.05),而后两者无显著差异(P＞0.05).结论:光固化机固有的软启动和脉冲照射模式不能增加树脂的表面流动补偿收缩能力,应用光强更低的前期台阶照射模式则可显著增加树脂的表面流动补偿收缩能力.     

含聚合单体微胶囊的牙科新型自修复抗菌复合树脂合成初探

目的 合成含聚合单体微胶囊的牙科新型自修复抗菌复合树脂,并探讨相关性能,为其进一步临床应用提供参考.方法 制备含聚合单体三乙二醇二甲基丙烯酸酯的微胶囊,分别以0、2.5％、5.0％、7.5％及10.0％质量分数添加至含长链烷基季铵盐新型纳米二氧化硅抗菌填料的复合树脂中,生成含聚合单体微胶囊的牙科新型自修复抗菌复合树脂(新型树脂组),以纳米瓷化复合树脂(Tetric N-Ceram)为对照.三点弯曲实验检测各组树脂弯曲强度和弹性模量(每组样本量为6);单刃V形切口梁法测试各组树脂断裂韧性及自修复效率(每组样本量为6),同时进行扫描电镜观察.结果 引入7.5％聚合单体微胶囊时,新型树脂组弯曲强度和弹性模量分别为(96.4±14.3) MPa和(6.2±1.1) GPa,与对照组[分别为(99.1±1 1.9) MPa和(6.1±1.1)GPa]差异均无统计学意义(P＞0.05);当聚合单体微胶囊质量分数为7.5％和10.0％时,新型树脂的自修复效率分别为(66.8±7.0)％和(79.3±9.7)％;扫描电镜示愈合面有黑色不规则薄膜覆盖.结论 含聚合单体微胶囊的牙科新型自修复抗菌复合树脂具有较强的自修复功能,展示了良好的临床应用前景.     

大块充填树脂在牙体修复中的应用与研究进展

传统复合树脂在临床应用中分层充填,步骤较多,树脂的聚合收缩可导致修复体边缘微渗漏、术后敏感等,导致修复失败.2009年,大块充填树脂(bulk-fill resin-based composite)应运而生,改良的基质单体、改性强化的纳米混合填料以及独特的光引发剂,使得大块充填树脂能够一层充填4 mm,其简化操作步骤、节约椅旁时间、并能显著降低聚合收缩和聚合应力.本文就大块充填树脂的分类、固化原理、性能等方面进行阐述和讨论,并提出大块充填树脂的应用发展方向.     

2种光固化灯固化对3种不同复合树脂聚合收缩的影响

目的:比较2种光固化灯对3种复合树脂聚合收缩的影响。方法:相移投影栅形貌测量仪测量Z100、Z250、AP-X等3种复合树脂在卤素灯和发光二极管固化灯开始固化后50s及开始固化后400s的树脂聚合收缩量。使用SPSS12.0软件包对QTH及LED固化组聚合收缩量进行单因素方差分析。结果:在开始固化后50s和400s,QTH固化灯和LED固化灯固化Z100、Z250树脂产生的聚合收缩量有显著差异,QTH固化灯固化Z100、Z250树脂产生的聚合收缩量显著大于LED固化灯(P<0.05),QTH和LED固化灯固化AP-X树脂产生的聚合收缩量则无统计学差异(P>0.05)。结论:LED及QTH固化灯固化Z100、Z250树脂产生的聚合收缩影响有显著差异(P<0.05),LED及QTH固化灯固化AP-X产生的聚合收缩无显著差异(P>0.05)。     

数字图像相关法在光固化复合树脂收缩变形测量中的应用

目的:探讨数字图像相关法在研究光固化复合树脂光照收缩变形产生和演化中的价值.方法:6颗新鲜、完整的离体磨牙,随机分为2组,邻面片切平整,制备2.0 mm×2.0 mm×2.0 mm的邻(牙合)面洞形,洞面酸蚀冲洗,涂黏结剂光照,第1组充填3M Z350纳米树脂,第2组充填3M Valux Plus(V.P)通用型树脂.邻面快速制造散斑,固定于微型试验夹中,光照40s,同步数码相机采集表面散斑序列图,以数字图像分析软件计算序列图各像素点水平方向(x)和垂直方向(y)位移、应变,采用SPSS 12.01软件包统计线性收缩率,并对20 s时游离面各点位移进行配对t检验.结果:序列图经处理后,相关系数R均＞0.98.树脂光照40 s内表现为各向异性收缩,2组材料x方向线收缩率分别为0.439％～0.75％ 、0.526％～0.834％,y方向线收缩率分别为0.253％～1.34％、0.355％～1.51％.20 s时,游离面Z350组在x和y方向变形均较V.P组小(P＜0.05).结论:应用数字图像相关法研究光固化复合树脂光照过程中的聚合收缩,能有效动态记录、计算全域收缩变形量,为提高临床使用效果提供依据.     

影响复合树脂聚合收缩应力的因素

随着人们对美观要求的日益提高和复合树脂性能的不断完善,复合树脂在口腔临床中的应用已变得日益广泛.目前对复合树脂性能上的改善主要集中在提高其机械性能,减少残余游离单体的释放以增强其生物安全性,减少聚合收缩的程度以防止微渗漏的形成和牙体变形等方面.而树脂发生聚合反应是其自身物理和化学特性所决定的,其收缩产生的应力对复合树脂性能有着重要影响.近年来,对影响树脂聚合收缩应力的因素已成为复合树脂研究的热点,本文就影响树脂聚合收缩应力的因素做一简要综述.     

显微CT在检测复合树脂聚合收缩中的应用

复合树脂固化时发生聚合收缩,可能会导致最终修复失败或引起其他并发症。应用显微CT(micro-computed tomography,micro CT)可以测量树脂聚合前后的体积变化及由此导致的微渗漏,并可通过示踪颗粒测量树脂聚合收缩矢量,以得到精确的收缩变化的相关数据。这种检测技术无创伤,立体直观,更精确、科学,该文就该技术进行综述。     

不同充填方式对复合树脂在盒形洞壁产生收缩应力的影响

目的:观察不同充填固化方式对复合树脂在盒形洞壁产生收缩应力的影响.方法:在厚度为4 mm、边长4 cm的聚碳酸酯板上制备直径4 mm、深3 mm的窝洞,涂布粘结剂后分别以4种充填固化方式充填复合树脂(卡瑞斯玛):①整体充填,照射40 s;②水平2层充填,每层照射20 s;③水平3层充填,每层照射20 s;④斜向3层充填,每层照射20 s.分别于照射后3 min、24 h在显微光弹仪上观测窝洞周围应力等差条纹的直径,计算出洞壁承受的收缩应力.结果:所有充填方式组固化后24 h的收缩应力均显著大于其固化后3 min的应力(P＜0.05);不同充填方式组间比较,无论是固化后3 min,还是24 h,均以斜向3层充填组的收缩应力最小,分别与其他各组相比差异均有统计学意义(P＜0.05);其次是水平3层充填固化组,显著小于整体充填固化组和水平2层充填组(P＜0.05);整体充填固化组收缩应力最大,但与水平2层充填组相比无统计学差异(P＞0.05).结论:分层充填能够降低盒形洞壁的收缩应力,其中斜向分层充填的效果最好.     

Photoelastic determination of polymerization shrinkage stress in low-shrinkage resin composites

Low-shrinkage resin composites are in the focus of research in posterior resin composite restoratives. The aim of the study was to examine the polymerization shrinkage stress of new composites (Venus Diamond/ Heraeus Kulzer; SDR/DENTSPLY) and an experimental low-shrinkage resin composite (Ormocer/VOCO) in comparison to established low-shrinkage resin composites (Filtek Silorane/ 3M ESPE; els/Saremco; Filtek Supreme XT/3M ESPE; Clearfil Majesty Posterior/Kuraray). Cylindrical cavities (? 4 mm) in Araldit-B epoxy resin plates (40×40×4 mm) were pretreated with the Rocatec system to ensure bonding of the resin composites. The resin composite specimens (n = 10) were exposed to light for 60 s with a QTH curing device (Translux energy, Heraeus Kulzer, Germany). The samples were stored dark and dry (23 °C). Polymeri-zation shrinkage stress data (MPa) 4 min and 24 h post exposure were calculated based on the diameter of the first-order isochromatic rings, obtained from the Araldit plates. The statistical analysis of the obtained data was carried out with the Wilcoxon test (p = 0.05). After 24 h, the following mean stress values and standard deviations were obtained: Venus Diamond 3.4 ± 0.27 MPa; SDR 3.3 ± 0.26 MPa; exp. Ormocer 4.0 ± 0.18 MPa; Filtek Silorane 2.8 ± 0.19 MPa; els 2.5 ± 0.09 MPa; Filtek Supreme XT 6.0 ± 0.20 MPa; and Clearfil Majesty Posterior 5.6 ± 0.15 MPa. For all materials, higher polymerization stress values were recorded after 24 h. All differences in the shrinkage data obtained after 24 h were statistically significant (p < 0.05) except Venus Diamond/SDR. Venus Diamond, els and SDR showed shrinkage data closer to that of Filtek Silorane.     

Repair of dimethacrylate-based composite restorations by a silorane-based composite: a one-year randomized clinical trial

SUMMARY Purpose : To investigate clinical performance of a low-shrinkage silorane-based composite resin when used for repairing conventional dimethacrylate-based composite restorations. Background : Despite the continued development of resin-based materials, polymerization shrinkage and shrinkage stress still require improvement. A silorane-based monomer system was recently made available for dental restorations. This report refers to the use of this material for making repairs and evaluates the clinical performance of this alternative treatment. Materials and Methods : One operator repaired the defective dimethacrylate-based composite resin restorations that were randomly assigned to one of two treatment groups: control (n=50) repair with Adper SE Plus (3M/ESPE) and Filtek P60 Posterior Restorative (3M/ESPE), and test (n=50) repair with P90 System Adhesive Self-Etch Primer and Bond (3M/ESPE) and Filtek P90 Low Shrink Posterior Restorative (3M/ESPE). After one week, restorations were finished and polished. Two calibrated examiners (Kw≥0.78) evaluated all repaired restorations, blindly and independently, at baseline and one year. The parameters examined were marginal adaptation, anatomic form, surface roughness, marginal discoloration, postoperative sensitivity, and secondary caries. The restorations were classified as Alpha, Bravo, or Charlie, according to modified US Public Health Service criteria. Mann-Whitney and Wilcoxon tests were used to compare the groups. Results : Of the 100 restorations repaired in this study, 93 were reexamined at baseline. Dropout from baseline to one-year recall was 11%. No statistically significant differences were found between the materials for all clinical criteria, at baseline or at one-year recall (p>0.05). No statistically significant differences were registered (p>0.05) for each material when compared for all clinical criteria at baseline and at one-year recall. Conclusions : The hypothesis tested in this randomized controlled clinical trial was accepted. After the one-year evaluations, the silorane-based composite exhibited a similar performance compared with dimethacrylate-based composite when used to make repairs.     

The repair potential of resin composite materials

Objectives

To measure the ‘repair’ strength of various combinations of composite using four manufacturers’ adhesive systems, to compare the bond strengths with the cohesive strength of the original, unrepaired products and to assess whether the chemical nature of the resin matrix influenced the repair strength.

Methods

Specimens were prepared of three composite materials Durafill, Heraeus Kulzer; P90 (Silorane) 3M ESPE; Z250 (3M ESPE) and aged in water at 60 °C for 1 month. One surface of each specimen was faced with 80-grit silicone carbide paper, one of four adhesives placed (Ecusit, DMG; Clearfil Repair, Kuraray; P90 System Adhesive; Single Bond 2, 3 M ESPE) and ‘repair’ composite added of the same type as above, such that all combinations of original and repair composite and adhesive were used. ‘Stick’ samples, approximately 6 mm × 0.8 mm × 4 mm were prepared from each repair specimen, a neck created at the junction of original and repair composites and the hour-glass sample tested in tension at 1 mm/min. The microtensile bond strength of the repair was calculated and the mode of failure (adhesive; cohesive in the original composite; cohesive in the repair composite) recorded.

Results

There was no significant difference between the cohesive strengths of Filtek P90 and Filtek Z250 (both ≈106 MPa); both were significantly stronger than Durafill (67.0 MPa). For bonding to Durafill the bond strengths ranged from 17.6 MPa to 50.9 MPa; for bonding to P90, the bond strengths ranged from 5.0 MPa to 54.2 MPa; for bonding to Z250, the bond strengths ranged from 17.2 MPa to 75.4 MPa. Clearfil Repair appeared to provide the most consistently high bond strengths, followed by the P90 System Adhesive, Single Bond 2 and Ecusit. Overall, the majority of failures (74%) was adhesive.

Significance

It appears that bonding of new dimethacrylate-based composite to old dimethacrylate-based composite can be a viable clinical procedure. However, if the original composite is silorane-based (e.g., P90), then using the silane-based adhesive may be the best repair option, and similarly if it is planned to effect a repair with a silorane-based composite, using a silane-based adhesive may give the best outcome. The null hypotheses are thus rejected.     

Contraction stress, elastic modulus, and degree of conversion of three flowable composites

The aim of this study was to measure the contraction stress of three flowable resin composites and to correlate the stress with the elastic modulus and the degree of conversion. One low-shrinkage (Venus Diamond Flow) and two conventional (Tetric EvoFlow and X-Flow) flowable composites were polymerized for 40s with a light-emitting diode (LED) curing unit. Contraction force was continuously recorded for 300s using a stress-analyser, and stress values were calculated at 40s and at 300s. The maximum stress rate was also calculated for each specimen. The elastic modulus of each composite was assayed using a biaxial flexural test, and degree of conversion was analysed with Raman spectroscopy. X-Flow exhibited higher stress values than the other tested materials. Venus Diamond Flow showed the lowest stress values at 40s and at 300s, and the lowest maximum stress rate. Stress values were correlated with elastic modulus but not with degree of conversion, which was comparable among all tested materials.     

Assessment of polymerization contraction stress of three composite resins.

OBJECTIVES: The purpose of this study was to measure the development of contraction stress of three composite resin restorative materials during photo-polymerization: a micro-hybrid composite (Filtek Z250, 3M ESPE, St. Paul, MN, USA); a nano-filled composite (Filtek Supreme, 3M ESPE, St. Paul, MN, USA); and a low-shrinkage composite (AElite LS, Bisco Inc., Schaumburg, IL, USA). METHODS: Curing shrinkage stress was measured using a stress-analyzer. Composites were polymerized with a halogen-curing unit (VIP, Bisco Inc., Schaumburg, IL, USA) for 40 s. The contraction force (N) generated during polymerization was continuously recorded for 150 s after photo-initiation. Contraction stress (MPa) was calculated at 20, 40, 60 and 150 s. Data were statistically analyzed. RESULTS: The low-shrinkage composite AElite LS exhibited the lowest stress values compared to other materials (p<0.05). Statistical analysis did not show significant differences between Filtek Z250 and Filtek Supreme. SIGNIFICANCE: The low-shrinkage composite showed lower contraction stress than micro-hybrid and nano-filled composite. Ideally, non-shrinking resins would represent the ultimate solution to overcome polymerization contraction and stress-related problems.     

How to repair fillings made by silorane-based composites

In 2007, the low shrinkage silorane-based composites with a completely new resin chemistry were introduced. As for the case of composite repair, the question of whether this new material class can be repaired with the same methods like dimethacrylate-based composites arises. The ability of a silorane-based composite (SBC) to be repaired was therefore examined in a shear-bond test. Specimens of SBC were polymerised, water-stored at 37°C for 1 week and then repaired with fresh dimethacrylate-based composite (MBC) or SBC material by using several intermediate agents (IMA). The shear-bond strength was then measured after an additional water storage of 1 week. As IMA, we tested an experimental silorane-flowable composite, two dimethacrylate-based flowable composites, a filled silorane system adhesive bond and a conventional unfilled adhesive, a silane in addition to an adhesive as well as a repair kit. Additionally, repairs of MBC with dimethacrylate-based flowable composite were prepared. Specimens of MBC and SBC bonded to dentine with the corresponding adhesives were used as a reference. The repairs of MBC with the flowable composite resin Tetric Evo Flow exhibited the highest mean repair bond strength value (42.2 MPa). For repair of SBC, the highest shear-bond strengths were measured for repairs using a silane additionally to a dimethacrylate-based adhesive resin, followed by repairs with the experimental silorane-based flowable composite resin Hermes Flow as IMA. SBC can be repaired in combination with a MBC; then a silane coupling agent plus a dimethacrylate-based IMA should be used. A silorane flowable as IMA is the best choice when SBC is to be repaired with SBC.     

Color stability of silorane-based composites submitted to accelerated artificial ageing--an in situ study

ObjectivesTo assess the in situ color stability, surface and the tooth/restoration interface degradation of a silorane-based composite (P90, 3M ESPE) after accelerated artificial ageing (AAA), in comparison with other dimethacrylate monomer-based composites (Z250/Z350, 3M ESPE and Esthet-X, Dentsply).MethodsClass V cavities (25 mm² × 2 mm deep) were prepared in 48 bovine incisors, which were randomly allocated into 4 groups of 12 specimens each, according to the type of restorative material used. After polishing, 10 specimens were submitted to initial color readings (Easyshade, Vita) and 2 to analysis by scanning electronic microscopy (SEM). Afterwards, the teeth were submitted to AAA for 384 h, which corresponds to 1 year of clinical use, after which new color readings and microscopic images were obtained. The values obtained for the color analysis were submitted to statistical analysis (1-way ANOVA, Tukey, p < 0.05).ResultsWith regard to color stability, it was verified that all the composites showed color alteration above the clinically acceptable levels (ΔE ≥ 3.3), and that the silorane-based composite showed higher ΔE (18.6), with a statistically significant difference in comparison with the other composites (p < 0.05). The SEM images showed small alterations for the dimethacrylate-based composites after AAA and extensive degradation for the silorane-based composite with a rupture at the interface between the matrix/particle.ConclusionIt may be concluded that the silorane-based composite underwent greater alteration with regard to color stability and greater surface and tooth/restoration interface degradation after AAA.     

Interactions of self-etch adhesives with resin composites

OBJECTIVE: Aim of this in vitro study was to investigate the correlation of shear bond strength and marginal cavity adaptation, together with polymerization shrinkage and contraction stress, using the combination of four self-etch adhesives and three resin composites. MATERIALS AND METHODS: Interactions were studied between one two-step and three one-step adhesives, and the hybrid-type resin composites, Beautifil (BEU, Shofu) and Venus (VEN, Heraeus), and an experimental nano-hybrid resin composite NEUN (NEU, Heraeus). For all 12 combinations shear bond strengths (SBS) were determined on human dentin. Marginal adaptation (MGW) was assessed in cylindrical butt-joint dentin cavities. Further, polymerization contraction and contraction stress of the resin restoratives were measured. RESULTS: Significant determinants of SBSs on dentin were time of testing (10min or 24h) and adhesives (p<0.001). Marginal adaptation was best for NEU, followed by VEN and BEU. Only the resin composite used was a highly significant determinant of cavity adaptation. Polymerization shrinkage after 5min was 2.58, 2.74, and 1.53% for BEU, VEN, and NEU, respectively. Polymerization contraction stresses were largest for BEU, less for VEN, and smallest for NEU (p<0.05). CONCLUSIONS: No correlation was found between bond strength and marginal cavity adaptation. In contrast, reduced shrinkage and low polymerization contraction stress of resin composites were identified as important determinants of marginal cavity adaptation.     

Polymerization contraction stress of low-shrinkage composites and its correlation with microleakage in class V restorations

OBJECTIVE: The aim of this study was to compare the behavior of two new, low-shrinkage hybrid composites (Aelite LS and Inten-S) with a microfilled (Heliomolar) and a hybrid composite (Filtek Z250), in terms of polymerization contraction stress and microleakage. METHODS: Maximum contraction stress after 10 min was recorded in a "tensilometer", using a C-factor (C) of 2.5 and energy density of 26 J/cm(2). For the microleakage test, cylindrical cavities with enamel margins prepared in bovine incisors (4 mm diameter, 1.5 mm depth, C = 2.5) were restored in bulk, applying the same energy density used in the contraction stress test. After immersion in 0.5% methylene blue for 4 h, specimens were sectioned twice, perpendicularly, and the highest dye penetration score was recorded. Contraction stress results were analyzed by one-way ANOVA/Tukey's test and microleakage was analyzed by Kruskal-Wallis test. Regression analysis between the two variables was also performed. RESULTS: Aelite LS showed significantly higher stress than the other composites tested. Inten-S and Filtek Z250 had similar stress levels, statistically higher than Heliomolar. In the microleakage test, a significant difference was observed between Aelite LS and Heliomolar only. Regression analysis showed a good linear correlation between the two variables (R2(adjusted) = 0.811). CONCLUSIONS: The low-shrinkage materials exhibited contraction stress values similar or higher than the hybrid composite. A direct relationship between contraction stress values and microleakage for the composites evaluated was verified. SIGNIFICANCE: The low-shrinkage composites tested did not seem to represent an improvement in terms of reducing contraction stress or microleakage.     

Bonding performance of self-adhesive flowable composites to enamel,dentin and a nano-hybrid composite

This study aimed to analyze bond strengths of self-adhesive flowable composites on enamel, dentin and nano-hybrid composite. Enamel, dentin and nano-hybrid composite (Venus Diamond, Heraeus Kulzer, Germany) specimens were prepared. Three self-adhesive composites (Constic, DMG, Germany; Fusio Liquid Dentin, Pentron Clinical, USA; Vertise Flow, Kerr Dental, Italy) or a conventional flowable composite (Venus Diamond Flow, Heraeus Kulzer, Germany, etch&rinse technique) were applied to enamel and dentin. Nano-hybrid composite specimens were initially aged by thermal cycling (5000 cycles, 5–55 °C). Surfaces were left untreated or pretreated by mechanical roughening, Al₂O₃ air abrasion or silica coating/silanization. In half of the composite specimens, an adhesive (Optibond FL, Kerr Dental, Italy) was used prior to the application of the flowable composites. Following thermal cycling (5000 cycles, 5–55 °C) of all specimens, shear bond strengths (SBS) and failure modes were analyzed (each subgroup n = 16). Statistical analysis was performed by ANOVAs/Bonferroni post hoc tests, Weibull statistics and χ ²-tests (p < 0.05). SBS (MPa) of the self-adhesive composites on enamel and dentin were significantly lower (enamel: < 5, dentin: < 3) than those of the conventional flowable composite (enamel: 13.0 ± 5.1, dentin: 11.2 ± 6.3), and merely adhesive failures could be observed. On the nano-hybrid composite, SBS were significantly related to the pretreatment. Adhesive application improved SBS of the conventional, but not of the self-adhesive composites. The self-adhesive composite groups showed less cohesive failures than the reference group; the occurence of cohesive failures increased after surface pretreatment. Bonding of self-adhesive flowable composites to enamel and dentin is lower than bonding to a nano-hybrid composite.