Effect of thermal cycling on the bond strength of self-adhesive cements to fiber posts

The aim of this study was to assess the push-out bond strengths of self-adhesive resin cements to epoxy resin-based fiber posts after challenging by thermocycling. Thirty-six single-rooted premolars were endodontically treated, and the post-spaces were drilled to receive RelyX Fiber posts #1. Three self-adhesive resin cements (RelyX Unicem, G-Cem, and Breeze) were used for luting fiber posts. The bonded specimens were either stored for 1 month in a moist field (37°C) or submitted to thermocycling (5,000 times) prior to push-out test. The maximum force required to dislodge the post via an apical-coronal direction was recorded (megapascal). The data were statistically analyzed with two-way ANOVA and Tukey tests (p < 0.05). The factors "luting cement" and "thermocycling" significantly influenced bond strengths. The initial push-out values of RelyX Unicem and Breeze were higher than those of G-Cem. After thermocycling, the bond strength of G-Cem increased and no differences were found between groups. RelyX Unicem and Breeze bond strengths were not affected by the thermal challenge. Thermal cycling and cement type differently influence the bond strengths of self-adhesive resin cements. Self-adhesive cements can represent an option for luting fiber posts into root canal.     

Effect of thermocycling on bond strength of luting cements to zirconia ceramic.

OBJECTIVES: The aim of this study was to evaluate the shear bond strength of different cements to densely sintered zirconia ceramic after aging by thermocycling. METHODS: The following luting cements for bonding ZrO2-TZP (tetragonal zirconia polycrystals) were used in this study: Ketac-Cem, Nexus, Rely X Unicem, Superbond C&B, Panavia F, and Panavia 21. Groups of 30 test specimens were prepared by bonding stainless steel cylinders tribochemically silica-coated with the Rocatec-system to sandblasted ZrO2-TZP ceramic disks (cercon smart ceramics). Prior to testing all bonded specimens were stored in distilled water (37 degrees C) for 48 h and half of them (n=15) were additionally aged by thermocycling (10,000 times). RESULTS: None of the fractures occurred at the interface of the metallic rods. The assemblies failed either at the interface between the ceramic surface and the cements or within the cements. Thermocycling affected the bond strength of all luting cements studied except for both Panavia materials and Rely X Unicem. SIGNIFICANCE: Within the limits of this in vitro study the results showed that-after thermocycling-bond strengths for Ketac-Cem and Nexus were quite low. Nexus in combination with tribochemical silica-coating of ceramic surface produced a higher bond strength. The four adhesive resin cements (Rely X Unicem, Superbond C&B, Panavia F, and Panavia 21) gave superior results. The strongest bond to zirconia was obtained with Panavia 21.     

Microtensile bond strength between adhesive cements and root canal dentin.

OBJECTIVES: The hypotheses tested were that the bond strength of adhesive cements to root canal dentin (1) would be reduced as a function of configuration factor, polymerization process and type of luting material and (2) would be lowered near the apex of the tooth. METHODS: Human canines and premolars were prepared for post cementation using Single Bond/Rely X ARC, ED Primer/Panavia F, C and B Metabond, and Fuji Plus. The specimens were divided into two groups. For intact roots, the posts were luted using standard clinical procedures. For flat roots, the posts were applied directly into flat ground canals. All roots were sectioned into 0.6 mm thick slices, trimmed mesio-distally and stressed to failure at 1 mm/min. The muTBS of each slab was calculated as the force at failure divided by the bonded cross-sectional surface area. The results were compared using a one-way ANOVA and Tukey multiple comparison intervals (alpha=0.05). Least squares linear regression analysis was used to assess the effect of dentin location on bond strength. RESULTS: All cements showed significantly (p相似文献   

Bonding effectiveness and sealing ability of fiber-post bonding

OBJECTIVES: To evaluate the push-out bond strength and the sealing ability of five adhesive cements routinely used for fiber-post bonding. METHODS: Fifty extracted single-rooted teeth were randomly divided in five groups and restored using Parapost FiberLux and the following luting agents: Panavia 21 (PAN), Clearfil Esthetic Cement (CLF), Variolink II (VAR), RelyX Unicem (UNI) and experimental GC self-adhesive cement (EGC). After 1 week of water storage at 37 degrees C, three sections (coronal, middle and apical) of 2mm thickness were prepared from each specimen. Sealing ability was quantified with a fluid-filtration system (Flodec) during 10 min, after which the push-out bond strength was immediately measured. Data were analyzed with ANOVA (push-out) and Kruskal-Wallis (sealing ability). RESULTS: The push-out bond strength and sealing ability were not significantly different among the coronal, middle and apical sections for each luting agent. The highest push-out bond strength was measured for CLF (14.60+/-3.63 MPa), which was not significantly different from PAN (12.57+/-2.45 MPa), but significantly higher than VAR (11.09+/-4.09 MPa), UNI (11.29+/-4.31 MPa) and EGC (7.65+/-4.79 MPa). When evaluating the sealing ability, significant differences were not found among PAN, CLF and VAR, and between UNI and EGC. The latter luting agents scored significantly lower than the former ones. The push-out bond strength was correlated to the sealing ability (p<0.001). SIGNIFICANCE: The self-etching MDP-based cements presented the highest push-out bond strength. Although the bonding effectiveness of self-adhesive cements appears promising, their interaction with root dentin might be too weak to minimize microleakage at the post-cement-dentin interface.     

3种树脂粘接水门汀与铸造纯钛粘接强度研究

目的：研究3种复合树脂粘固剂与铸造纯钛的粘接强度。方法：用牙科铸钛的方法制作直径分别为4mm和5mm的钛棒,切割成长度为4mm的小钛片。2种规格的钛片配对粘接面用400～1200目碳化硅砂纸在流水下打磨抛光,使之呈均匀一致的平面。50μm氧化铝喷砂,另一组表面不喷砂作为对照,分别使用Super-BondC＆B、Panavia F、Rely X Unicem 3种复合树脂粘固剂粘接。扫描电镜观察喷砂前后铸造纯钛的表面形态。复合树脂粘接剂固化后经37℃恒温水浴24h以及5000次5～55℃冷热循环,测试剪切强度。用SAS的ANOVA过程对各组数据进行分析。结果：喷砂前后纯钛与Panavia F的剪切强度最高,分别为（26.62±3.40）MPa、（23.71±5.28）MPa;5000次冷热循环后,喷砂组的铸造纯钛与Panavia F的剪切强度最高（27.12±8.68）MPa;未喷砂的铸造纯钛与Super-Bond C＆B、Rely X Unicem的粘接强度最低,并且有12.5%的脱落率。结论：本实验结果表明喷砂可以提高Super-Bond C＆B、Panavia F、Rely X Unicem的粘结力和粘结耐久力。不喷砂时,Panavia F与铸造纯钛之间能获得较高的粘接强度和良好的粘接耐久性,喷砂以后优势不再明显。     

偶联剂和不同粘接剂对纤维桩粘接强度的影响

目的:利用薄片推出实验比较硅烷偶联剂和三种树脂粘接剂对纤维桩剪切粘接强度的影响.方法:60颗因牙周病等原因拔除的上颌单根前牙,根管治疗后行纤维桩修复的桩道预备.随机分为5组,每组12颗牙.分别采用下列粘接剂粘接Matchpost纤维桩:A组:Paracore粘接剂+偶联剂;B组:Paracore粘接剂;C组:Panavia F粘接剂+偶联剂;D组:Panavia F粘接剂;E组:Multilink N粘接剂+偶联剂.纤维桩粘接后,在牙根中部横向切割1.0mm层厚切片2个,在Zwick Z100材料试验机上行薄片推出试验(Push-Out Bond Test),记录失败载荷,计算剪切粘接强度,体视显微镜观察粘接失败类型.结果采用SPSS 11.5进行方差分析和χ2检验.结果:五组样本的剪切粘接强度(MPa)分别为A组:14.69±2.76;B组:9.46±3.11;C组:13.12±3.10;D组:10.40±3.30;E组:13.86±3.81,方差分析提示五组间差异有统计学意义(P <0.01).采用偶联剂处理时,Paracore粘接剂和Panavia F粘接剂与纤维桩间的剪切粘接强度均高于未用偶联剂处理者(P <0.05).采用偶联剂处理时,三种树脂粘接剂与纤维桩的剪切粘接强度间差异无统计学意义(P >0.05).五组粘接失败类型间差异有统计学意义(P <0.05),未采用硅烷偶联剂处理纤维桩表面者,出现纤维桩-粘接剂界面失败者增多.结论:在树脂粘接前,玻璃纤维桩表面氢氟酸酸蚀后,采用硅烷偶联剂处理可显著提高纤维桩与树脂粘接剂间的剪切粘接强度.     

Morphological and bond strength evaluation of different resin cements to root dentin

This study correlated the morphological characteristics with the bond strengths of various resin cements used for bonding fiber posts to root canal dentin. Fifty glass-fiber posts (FRC Postec Plus) were luted into the root canals of extracted human anterior teeth using five resin cements ( n  = 10): Panavia F 2.0, PermaFlo DC, Variolink II, RelyX Unicem, and Clearfil Core. Before insertion of the post, the adhesive systems were labeled with fluorescein and the resin cement was labeled with rhodamine isothiocyanate. The roots were sectioned into three slices (of 2 mm thickness), and each slice was analyzed using confocal laser scanning microscopy in dual fluorescence mode to determine hybrid layer thickness, the number of resin tags, and the number of broken tags. Bond strengths were measured using a micro push-out test. Bond strengths to root canal dentin, as well as the morphological characteristics, were significantly affected by the materials. However, these factors did not correlate. The self-adhesive resin cement, which showed the formation of a hybrid layer and resin tags only sporadically, had the highest bond strengths. These results indicate that chemical interactions between the adhesive cement and hydroxyapatite may be more crucial for root dentin bonding than the ability of the same material to hybridize dentin.     

Tensile bond strength of dual curing resin-based cements to commercially pure titanium.

OBJECTIVES: The aim of this study was to evaluate the tensile bond strength of dual curing luting resin cements to commercially pure titanium at 10 min and 24h after removal of the oxide layer. METHODS: One hundred and twenty titanium discs were obtained by casting and polishing with silicon carbide papers. The titanium discs were sandblasted with 50 microm aluminum oxide, ultrasonic cleaned and bonded in pairs with the resin-based cements Panavia F and Rely X ARC at 10 min and 24h after the sandblasting. The tensile test was performed with a crosshead speed of 0.5mm/min in an Instron Universal testing machine. RESULTS: The Rely X ARC reached the highest tensile strength value at 24h after sandblasting (18.27 MPa), but there was no statistically significant difference between the two dual curing resin cements for both times tested. All specimens showed a mixture of cohesive fracture in the resin cement and adhesive failure. However, the predominant failure mode for Panavia F was cohesive in resin cement, and the Rely X ARC exhibited a greater proportion of specimens with adhesive failure between the alloy and resin luting cement at 10 min and 24h. SIGNIFICANCE: Both cements had, statistically, the same tensile bond strength. But in the fracture mode analysis, the adhesive predominant fracture mode of Rely X ARC cement indicates a premature clinical adhesive failure. On the other hand, the cohesive predominant fracture mode of Panavia F indicates a longer clinical adhesive bond with titanium.     

Bonding of resin composite luting cements to zirconium oxide by two air-particle abrasion methods

OBJECTIVE: This study evaluated the shear bond strength of two resin composite luting cements to zirconium oxide ceramic substrate using two air-particle abrasion methods. METHODS: Two resin composite cements, RelyX Unicem (3M ESPE) and Panavia F (Kuraray), each with an acidic composition, were used in combination with a zirconium oxide (DCS Dental AG) substrate containing Al2O3 and SiO2 (Rocatec system, 3M ESPE) and two air-particle abrasion methods. The shear bond strength of the resin composite cement to the substrate was tested after the samples were either water-stored for one week or thermocycled following 24 hours of water storage. RESULTS: The RelyX Unicem resin composite cement specimens with the Rocatec treatment (20.9 +/- 4.6 Mpa and 20.1 +/- 4.2 MPa, respectively, n = 12) demonstrated the highest shear bond strength. Alternatively, the lowest values were obtained for the Panavia F resin cement samples, with Al2O3 air-particle abrasion in both storage conditions, water storage for one week (17.7 +/- 8.9MPa) or thermocycling after 24 hours of water storage (16.3 +/- 4.9 MPa). Neither storage condition or particle abrasion system significantly affected shear bond strengths (ANOVA, p > 0.05). CONCLUSION: It was concluded that two different surface conditioning methods and storage conditions did not significantly affect the bonding properties of Panavia F and RelyX Unicem resin composite luting cements to Zirconia.     

Reliability of fiber post bonding to root canal dentin after simulated clinical function in vitro

The aim of this study was to investigate the effect of thermomechanical loading (TML) on the bond strength of fiber posts luted with three different resin cements. Sixty-six extracted human anterior teeth were endodontically treated and restored with fiber posts (RelyX Fiber Posts, 3M ESPE) using three commercially available resin cements and three corresponding core build-up materials (n=22 each): Panavia F 2.0/Clearfil DC Core Automix (Kuraray), Variolink II/Multicore Flow (Ivoclar Vivadent), and RelyX Unicem/Filtek Z250 (3M ESPE). Twelve specimens of each group received all-ceramic crowns and were subjected to TML. The other 10 specimens were stored in saline solution for 24 hours. The roots were sectioned and bond strength was measured using a push-out test. Adhesive interfaces of two specimens of each group subjected to TML were analyzed using field emission scanning electron microscopy (FESEM). Bond strengths of fiber posts were significantly affected by the type of resin cement (p<0.0005) and TML (p<0.0005; two-way analysis of variance). TML significantly reduced bond strengths for all materials ((6.0 (6.2) MPa)) compared with initial bond strengths ((14.9 (10.4) MPa)). RelyX Unicem resulted in significantly higher bond strengths before ((18.3 (10.3) MPa)) and after TML ((9.8 (7.5) MPa)) compared with the other materials (p<0.0005; Tukey HSD). Using FESEM, Variolink II and Panavia F demonstrated a hybrid layer partly detached from the underlying resin cement, whereas no hybrid layer was observed for RelyX Unicem. The decrease in bond strength after TML suggests that retention of fiber posts may be reduced after clinical function. Therefore, endodontically treated teeth that are restored using fiber posts may benefit from additional reinforcement via coronal restorations using adequate ferrules and/or adhesive techniques.     

Evaluation of the adhesion of fiber posts to intraradicular dentin

The interfacial strength and ultrastructure of a total-etch, self-etch and self-adhesive resin cement used to lute endodontic glass fiber posts (FRC Postec, Ivoclar-Vivadent) was assessed with the "thin-slice" push-out test and transmission electron microscopy (TEM). The tested adhesive cements were Variolink II (Ivoclar-Vivadent), Panavia 21 (Kuraray Co) and RelyX Unicem (3M ESPE). In each group, seven posted roots were used for push-out tests and two were processed for TEM observations. The interfacial strength achieved by Variolink II (10.18 +/- 2.89 MPa) was significantly higher than Panavia (5.04 +/- 2.81 MPa) and RelyX Unicem (5.01 +/- 2.63 MPa), which were comparable to each other. TEM micrographs of the interface between Variolink II and intraradicular dentin revealed that the smear layer was totally removed and an 8-10 micron thick hybrid layer was formed. In the other group specimens, the smear layer was not completely dissolved and smear plugs were retained. Gaps were present between the hybridized complex and the adhesive layer in the Panavia 21 specimens and between the smear layer and underlying root dentin in the RelyX Unicem specimens. Interfacial strengths and microscopic findings were in agreement and indicated that the bonding potential of the total-etch resin cement was greater. The acidic-resin monomers responsible for substrate conditioning in Panavia 21 and RelyX Unicem appeared unable to effectively remove the thick smear layer created on root dentin during post space preparation.     

不同黏结方法和不同桩道部位对纤维桩黏结强度的影响

目的:比较不同黏结方法在不同桩道部位对纤维桩黏结剪切强度的影响。方法:选取42颗离体上颌中切牙,根管治疗桩道预备后根据不同的黏结方法随机分为6组,Ⅰ组为全酸蚀黏结剂Luxabond+自黏结树脂水门汀Rely X TM Unicem,Ⅱ组为全酸蚀黏结剂Luxabond+双固化树脂水门汀Luxacore,Ⅲ组为自酸蚀黏结剂Contax+自黏结树脂水门汀 Rely X TM Unicem,Ⅳ组为自酸蚀黏结剂Contax+双固化树脂水门汀Luxacore,Ⅴ组为自黏结树脂水门汀Rely X TM Unicem,Ⅵ组为双固化树脂水门汀Luxacore。纤维桩黏固后行薄片推出实验,并在扫描电镜下观察黏结界面及根管内壁的微观形态。采用SPSS13.0软件包对数据进行统计学分析。结果:不同黏结方法纤维桩的黏结强度差异具有显著性(P<0.05),第Ⅰ组和第Ⅲ组的黏结强度最高。扫描电镜观察,Ⅰ组和Ⅱ组的黏结界面有树脂突形成,黏结界面也更加致密。结论:自黏结树脂水门汀Rely XTM Unicem若配合使用全酸蚀及自酸蚀黏结剂,可显著提高纤维桩的黏结强度。     

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目的观察Rely X ABC、Para Cem Universal DC和Rely X Unicem 3种临床常用的树脂黏结剂黏固纤维桩的效果。方法选择2006年6月至2008年6月于中国医科大学口腔医学院修复科采用纤维桩修复并完善根管治疗的42例前牙牙体缺损患者的99颗患牙,随机分为3组,每组33颗,分别用不同的黏结剂(Ⅰ组:Rely X ARC;Ⅱ组:ParaCem Universal DC;Ⅲ组:Rely X Unicem)黏固纤维桩。随访0.5～2年,观察修复效果。结果Rely X ARC、ParaCem Universal DC和Rely X Unicem 3种树脂黏结剂用于黏固纤维桩的成功率依次为93.9%、84.8%、97.0%。结论Rely X ARC和Rely X Unicem黏结剂用于临床黏固纤维桩均表现出良好的临床效果。     

Adhesion of Indirect MOD Resin Composite Inlays Luted With Self-adhesive and Self-etching Resin Cements

SUMMARY This study investigated the effect of loading on the bond strength to dentin and microleakage of MOD indirect composite restorations bonded with self-adhesive and self-etching resin cements with or without acid etching of the proximal enamel margins. Class II MOD cavities were prepared in 48 molar teeth into dentin and divided into three groups of 16 teeth. Impressions were taken and indirect composite inlays fabricated (Estenia C & B). The enamel margins of the proximal boxes of half the specimens were phosphoric acid etched, and the inlays were cemented with one of three cements (Panavia F 2.0, SA Cement, or Rely X Unicem). After luting, eight teeth in each cement group were mechanically loaded at 2.5 cycles/s for 250,000 cycles. Unloaded teeth acted as controls. Teeth were stored in Rhodamine B solution for 24 hours, sectioned buccolingually at the proximal boxes to examine microleakage using confocal microscopy, and further sectioned for μTBS testing of the resin-dentin interface. Analysis of variance was performed to assess the effect of loading and acid etching on microleakage and bond strength. Acid etching had no effect on microleakage. No significant difference in the dentin bond strengths between the three cements existed after loading. Panavia F 2.0 exhibited a significant reduction in bond strength. With regard to microleakage at the proximal boxes, loading had no effect on dye penetration at the cavity floor. However, at the axial walls, loading had a significant deleterious effect on Panavia F 2.0. No difference in microleakage existed between the three cements at both sites before and after loading. In conclusion, the two tested self-adhesive cements exhibited similar bond strengths before and after loading to the self-etching resin cement. Loading reduced dentin bond strengths and increased microleakage at the resin-dentin interface. However, acid etching of the enamel margins had no significant effect on microleakage in the approximal regions of the bonded inlays.     

Early bond strength of two resin cements to Y-TZP ceramic using MPS or MPS/4-META silanes

For cementation of yttrium-stabilized tetragonal zirconium polycrystal (Y-TZP) ceramic frameworks, protocols of surface-conditioning methods and available cements vary, resulting in confusion among clinicians regarding selection and effects of different conditioning methods on cement adhesion. This study evaluated the effect of two silanes (3-trimethoxysilylpropylmethacrylate (MPS) and 3-trimethoxysilylpropylmethacrylate/4-methacryloyloxyethyl trimellitate anhydride methyl methacrylate (MPS/4-META) on the adhesion of two resin-based cements (SuperBond and Panavia F 2.0) to Y-TZP ceramic and compared several protocols with those indicated by the manufacturer of each of these cements. Disks of Y-TZP ceramic (LAVA, 3M ESPE) (n = 60) were divided into six experimental groups (n = 10 per group) and treated as follows: (1) silica coating (SC) + MPS silane + SuperBond; (2) SC + MPS/4-META + silane + SuperBond); (3) SC + MPS silane + Panavia F 2.0); (4) SC + MPS/4-META silane + Panavia F 2.0); (5) no conditioning + MPS/4-META silane + Super-Bond (SuperBond instructions); and (6) 50-μm Al₂O₃ conditioning + Panavia F 2.0 (Panavia F 2.0 instructions). The specimens were subjected to shear-bond testing after water storage at 37°C for 3 months in the dark. Data were analyzed by analysis of variance and Tukey’s HSD (α = 0.05). After silica coating, the mean bond strength of SuperBond cement was not significantly different between MPS and MPS/4-META silanes (20.2 ± 3.7 and 20.9 ± 1.6 MPa, respectively), but the mean bond strength of Panavia F 2.0 was significantly higher with MPS silane (24.4 ± 5.3 MPa) than with MPS/4-META (12.3 ± 1.4 MPa) (P < 0.001). The SuperBond manufacturer’s instructions alone resulted in significantly higher bond strength (9.7 ± 3.1 MPa) than the Panavia F 2.0 manufacturer’s instruction (0 MPa) (P < 0.001). When silica coating and silanization were used, both SuperBond and Panavia F 2.0 cements demonstrated higher bond strengths they did when the manufacturers’ instructions were followed. With SuperBond, use of MPS or MPS/4-META silane resulted in no significant difference when the ceramic surface was silica coated, but with Panavia F 2.0, use of MPS silane resulted in a significantly higher bond strength than use of MPS/4-META. Use of chairside silica coating and silanization to condition the zirconia surface improved adhesion compared with the manufacturers’ cementation protocols for SuperBond and Panavia F 2.0 resin cements.     

Various conditioning methods for root canals influencing the tensile strength of titanium posts

Conditioning the root canal is frequently advised to achieve high post-retention when resin composite luting cements are used. However, manufacturers' instructions for this purpose differ widely from one another. The aim of this study was to compare the tensile bond strengths of passive, tapered, titanium root posts that were luted with four different resin composite cements (Compolute Aplicap, Flexi-Flow cem, Panavia 21 EX, Twinlook) in the root canals at three conditions, namely (i) no conditioning, (ii) etching with 37% phosphoric acid, and (iii) etching + bonding agent application. Panavia 21 EX was further tested after using the primer for the post-surface according to the manufacturer's recommendations. The posts luted with zinc phosphate cement (Tenet) acted as the control group. Following endodontic preparation of 140 intact anterior teeth with hand instruments, the post-spaces were prepared using the opening drills of the corresponding size of the posts. The samples were first stored in water at 37 degrees C for 24 h and then thermocycled (5000 cycles, 5-55 degrees C, 30 s). The tensile strength values were measured with the universal testing machine at a crosshead speed of 0.5 mm min(-1). The data were analysed statistically using anova and corrected with Scheffé test due to the significance levels (P < 0.05). The tensile bond strengths of the titanium posts after luting with various cements and thermocycling were affected by the conditioning systems used for the root canals. Tensile bond strengths were the highest with Flexi-Flow (475 +/- 78 N) followed in descending order by Panavia 21 EX (442 +/- 97 N), Twinlook (430 +/- 78 N) and Compolute Aplicap (352 +/- 76 N) after conditioning the root canal. The use of primer on the post improved the tensile bond strength compared with the non-conditioned group for the Panavia 21 EX group (375 +/- 77 N) (P < 0.001). Tensile bond strengths obtained after luting the posts with zinc phosphate cement (414 +/- 102 N) were not significantly different (P < 0.05) than those of resin composite cements. Although the importance of conditioning the root canal was evident for Panavia 21 EX, it was not the case for the other luting cements tested.     

Bond strengths of resin cements to fiber-reinforced composite posts

PURPOSE: To evaluate the bond strengths of six different luting cements to fiber-reinforced composite (FRC) posts after various pre-treatment procedures. METHODS: 180 FRC posts were divided into three groups (n=60) and received the following surface treatments. Group 1: untreated control; Group 2: silane treatment; Group 3: CoJet treatment. The posts of each group were fixed with six different luting cements. Push-out tests were performed to determine the bond strengths between the cements and the fiber posts. RESULTS: The observed bond strengths (MPa) of the different resin cements to the posts were significantly affected by the type of cement (P< 0.001), but not by the pre-treatment chosen (P> 0.05; 2-way-ANOVA). Without consideration of the pre-treatment procedures, Clearfil showed the highest bond strengths, followed by Panavia F and RelyX, whereas Multilink, Variolink and PermaFlo showed significantly lower bond strength values (P< 0.05; Tukey's B).     

Effects of different luting cements and light curing units on the sealing ability and bond strength of fiber posts

This study evaluated the sealing ability and push-out bond strength of two luting cements cured with two different types of light curing units (LCU): light-emitting diode (LED) versus quartz tungsten halogen (QTH). Forty teeth were divided into four groups(n=10/group). Quartz fiber posts (D. T. Light-Post) were luted to coronal or apical section of root canals using two types of resin cements (Panavia F or RelyX) cured with either LED LCU (Elipar FreeLight II) or QTH LCU (Optilux 501). Highest push-out bond strength was exhibited by QTH-cured RelyX, which was not significantly different from LED-cured RelyX but was higher than QTHcured Panavia F. The push-out bond strength of Panavia F did not differ with LCU type (p>0.05), but exhibited lower values than both QTH- and LED-cured RelyX. Fluid filtration test revealed that sealing ability was not influenced by luting cement type, but was signifi cantly influenced by LCU type in favor of QTH light source: QTH-cured specimens displayed better seal than LED-cured ones (p<0.05).     

Challenges in luting fibre posts: Adhesion to the post and to the dentine

Objective

To investigate the relationship between physicochemical interactions of resin luting cements with dentine and retention of fibre posts in root canals.