Evaluation of surface roughness and bond strength of quartz fiber posts after various pre-treatments

Purpose. Debonding at the post-adhesive interface is a major problem for quartz fiber posts. The objective of this study was to evaluate surface roughness and bond strength of quartz fiber posts after various surface treatments. Materials and methods. Sixty-six quartz fiber posts were randomly divided into six experimental groups (n = 11) including group C, untreated (control); group SB, sandblasted; group SC, silica coated; group HF, hydrofluoric acid-etched; group N, Nd:YAG laser irradiated; group E, Er:YAG laser irradiated. Surface roughness of the posts was measured before and after pre-treatment. They were then bonded to resin cement and tensile bond strength was determined in a universal testing machine. Furthermore, two-way ANOVA and post hoc comparison tests (α = 0.05) were performed on all data. Results. The highest mean force value was observed in group SB and followed by group E. Tukey’s HSD test showed that there was no statistical difference between group SB and group E (p = 0.673). The highest mean roughness value was observed in group SB and a significant difference was found between group SB and all other groups (p < 0.001). This study reveals that sandblasting and Er:YAG laser irradiation provided a significant increase in bond strength between quartz fiber posts and resin cement. Conclusions. Sandblasting or Er:YAG laser-irradiation of the surface of the quartz fiber post before cementation is recommended for increasing retention.     

Influence of Different Surface Pretreatments of Zirconium Dioxide Reinforced Lithium Disilicate Ceramics on the Shear Bond Strength of Self-Adhesive Resin Cement

AimTo analyze the influence of different surface pretreatments of zirconium dioxide reinforced lithium disilicate ceramics on the shear bond strength of self-adhesive resin cement.Materials and methodsEighty-four zirconium reinforced lithium disilicate disc Vita suprinity (Vita Zahnfabrick, Bad Säckingen, Germany) 14x12x2 mm specimens were fabricated according to the manufacturer''s recommendations. The specimens were embedded in acrylic resin blocks and randomly divided in seven groups (n=12/each) accorrding to the treatment: Group 1- 10% hydrofluoric acid; Group 2- silane; Group 3- hydrofluoric and silane; Group 4- sandblasting with silane; Group 5- Er: YAG laser+ silane; Group 6- Nd: YAG laser + silane; and the control group, in which the specimens were not treated. Round shape composite discs (Filtek Bulk fill, 3M ESPE, St.Paul, Minnesota, USA) with 3.5 mm diameter, were made for shear bond strength testing, and then cemented to the ceramic sample surface using composite cement (RelyX U200 Automix, 3M ESPE, Neuss, Germany). After cementing the composite disc on the sample, the samples were subjected to shear bond strength test of 10 N with a “stress rate” of 1 MPa / s. To determine the nature of the fracture (adhesive, cohesive or adhesive-cohesive), the broken samples were examined under a stereomicroscope. The ANOVA test and the Tukey test were used to compare the values ​​of the bond strength characteristics between different types of materials. All tests were performed with a significance level of α = 0.05.ResultsThere was a significant difference in the shear bond strength of self-adhesive cement to dental lithium-disilicate ceramics reinforced with zirconium dioxide after different preparation protocols (p<0, 05). The treatment of lithium disilicate ceramics reinforced with zirconium dioxide by silanization, sandblasting + silanization, Nd: YAG + silanization resulted in significantly higher bond strength compared to the control group. There was statistically higher bond strength of self-adhesive cement after pretreatment of lithium disilicate ceramics Nd: YAG + silanization compared to Er: YAG + silanization (p <0.05). Adhesive fracture dominated in the control group, sandblasting + silanization group, and in the laser groups, while mixed fracture dominated in other groups.ConclusionUnder the limitations of this study, the Nd:YAG irradiation with silanization could be used as pretreatment for providing greater shear bond strength of self-adhesive resin cement to zirconium reinforced lithium disilicate.     

UV irradiation improves the bond strength of resin cement to fiber posts

The purpose is to evaluate the effect of UV irradiation on the bond strength between epoxy-based glass fiber posts and resin cement. Twelve epoxy-based glass fiber posts were randomly divided into three groups. Group 1 (Cont.): No surface treatment. Group 2 (Low-UV): UV irradiation was conducted from a distance of 10 cm for 10 min. Group 3 (High-UV): UV irradiation was conducted from a distance of 1 cm for 3 min. A resin cement (CLEARFIL SA LUTING) was used for the post cementation to form resin slabs which contained fiber posts in the center. Microtensile bond strengths were tested and the mean bond strengths (MPa) were 18.81 for Cont. group, 23.65 for Low-UV group, 34.75 for High-UV group. UV irradiation had a significant effect on the bond strength (p<0.05). UV irradiation demonstrates its capability to improve the bond strength between epoxy-based glass fiber posts and resin cement.     

Effects of dentin surface treatments including Er,Cr:YSGG laser irradiation with different intensities on the push-out bond strength of the glass fiber posts to root dentin

Abstract

Objective. Intra-canal post systems are commonly used to restore root-filled teeth. Bond strengths of the posts can be affected by various surface treatments of the post or the dentin. The aim of this study was to evaluate the effects of dentin surface treatments including erbium-chromium; yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser irradiation with different intensities on the push-out bond strength of the glass fiber posts to root dentin. Materials and methods. Forty single-rooted human maxillary incisors were filled and post spaces were prepared. After these procedures, the specimens were divided randomly into four groups according to the dentin surface treatments, as follows: (i) untreated surface (control), (ii) 1W Er,Cr:YSGG laser application, (iii) 2W Er,Cr:YSGG laser application and (iv) 3W Er,Cr:YSGG laser application. Then the posts were cemented into the root canals using dual-cured resin cement. Bonded specimens were cut into 1-mm-thick slices and push-out tests were performed using a universal testing device. All specimens were loaded until fracture and the failure modes were evaluated with a stereomicroscope at 32× magnification. Representative specimens were analyzed by scanning electron microscopy. Data were analyzed using a one-way ANOVA, Tukey and Wilcoxon tests. Results. The bond strength values ranged from 3.22–4.68 MPa. There were no statistically significant differences among the groups, regardless of the different levels. The coronal and middle levels of the post space had significantly higher bond strength values compared with the apical level (p < 0.05). Conclusion. Er,Cr:YSGG laser irradiation with different intensities did not increase the bond strength of the fiber posts to the root canal dentin walls.     

The Effect of Laser Treatment on Bonding Between Zirconia Ceramic Surface and Resin Cement

Abstract

Objective. The purpose of this in-vitro study was to evaluate and compare the effects of different surface treatments and laser irradiation on the shear bond strength of resin cement to zirconia-based ceramic. Material and methods. Forty zirconia core specimens (10-mm diameter, 2-mm thickness) were produced and embedded in the centers of autopolymerizing acrylic resin blocks. Subsequently, specimens were randomly divided into four groups, each containing 10 specimens, for different surface treatment methods. The details of the groups are as follows: Group C, no treatment applied (control); Group SB, bonding surfaces of ceramic disks were airborne particle-abraded with 110-μm alumina oxide particles; Group HF, bonding surfaces of ceramic disks were etched with 9.6% hydrofluoric acid; and Group L, bonding surfaces of ceramic disks were irradiated by a CO₂ laser. A total of 40 composite resin disks were fabricated and cemented with an adhesive resin cement to the specimen surfaces. A universal test machine was used for the shear bond strength test at a crosshead speed of 1 mm/min. Results. The highest shear bond strength values were obtained with Group L (20.99 ± 3.77 MPa) and the lowest values with Group C (13.39 ± 3.10 MPa). Although there was no significant difference between Groups C, HF and SB (P > 0.05), Group L showed a significant difference from all other groups (p < 0.05). Conclusion. All surface treatment methods improved the bond strength between resin cement and the zirconium oxide ceramic surface. CO₂ laser etching may represent an effective method for conditioning zirconia surfaces, enhancing micromechanical retention and improving the bond strength of resin cement on zirconia ceramic.     

Effect of different surface treatments on the shear and microtensile bond strength of resin-modified glass ionomer cement to dentin

Objective. The aim of this study was to evaluate the effect of different surface treatments on the microtensile bond strength (μTBS) and shear bond strength (SBS) of resin-modified glass ionomer cement (RMGIC) to dentin. Materials and methods. Fifty-two extracted human molars were flattened to obtain dentin surfaces. For SBS assessment 40 teeth were divided into four groups according to their surface treatments (acid etching, Er:YAG laser QSP mode, Er:YAG laser MSP mode and control-SiC) (n = 10). A plastic cylinder was placed over the differently treated dentin surfaces and RMGIC was placed into the rings and polymerized. Twelve teeth were used for the μTBS test. The treated dentin surfaces described above were restored with 4 mm high RMGIC and light cured; then, the specimens were sectioned into serial sticks (n = 15) and μTBS and SBS were tested for failure in a testing machine with a 1 mm/min crosshead speed. The data were analyzed by one-way ANOVA and Tukey HSD tests (α = 0.05). Results. Acid etching showed significantly higher SBS than the other groups (p < 0.05). Er:YAG QSP and MSP-treated groups showed higher SBS values than the control group, but the difference was not statistically significant (p > 0.05). Er:YAG MSP showed the highest μTBS value followed by acid etching, whereas the control group exhibited the lowest value (p < 0.05) and the differences between the control group and Er:YAG QSP were not significant (p > 0.05). Conclusions. The application of Er:YAG MSP mode and acid etching to dentin can be used for improving the bond strength of RMGIC.     

The effect of luting cement thicknesses on the push-out bond strength of the fiber posts

Abstract

Objective. The aim of this study was to evaluate the effect of luting cement thicknesses on the push-out bond strength of the fiber posts. Materials and methods. Sixty human maxillary canine teeth were endodontically treated. Post spaces were prepared and root specimens randomly divided into three groups: Group 1: etch-and-rinse (Variolink II/Exite DSC), Group 2: self-etch (Panavia F2.0/ED primer) and Group 3: self-adhesive (Clearfil SA Cement). Then each group was divided into four sub-groups according to the cement thickness, as follows: Sub-group 1: 0.35 mm, Sub-group 2: 0.25 mm, Sub-group 3: 0.15 mm, and Sub-group 4: 0.05 mm. Three slices of 1 mm thickness were obtained from each root specimen (n = 15). Push-out tests were performed and data was analyzed with two-way ANOVA and Tukey tests. Results. The etch-and-rinse system (Variolink II) had a significantly higher bond strength compared with the other systems (?p < 0.05). The thickest cement group (0.35 mm) had a significantly lower bond strength compared with the 0.15 and 0.05 mm groups in the etch-and-rinse and self-adhesive groups (p < 0.05). In the self-etch group, the cement thicknesses did not significantly affect the bond strength (p > 0.05). Conclusions. The etch-and-rinse system offered better bonding to root dentine than the self-adhesive and self-etch systems. The increases in cement thickness significantly reduced the bond strength of fiber posts to root dentine for both the etch-and-rinse and self-adhesive systems.     

Influence of laser irradiation on the push-out bond strength between a glass fiber post and root dentin

Statement of problem

A major issue related to the failure of endodontically treated teeth restored with an intraradicular post is gradual debonding of the glass fiber post, resin cement, and dentin.

Effects of different surface pre-treatments on the bond strength of adhesive resin cement to quartz fiber post

Abstract

Objective. The purpose of this study was to evaluate the effect of mechanical and chemical surface treatment methods on the bond strength of resin cement to fiber post. Materials and methods. The roots of 36 maxillary central incisor teeth were mounted in auto polymerized acrylic resin blocks (10 × 15 mm) and the root canals were enlarged with the drills of post system (2.1 mm width, 12 mm length). Thirty-six fiber posts were randomly assigned to one of the following surface conditioning methods: silane coupling agent, methylene chloride etching, 24% hydrogen peroxide etching, air abrasion with 50 µm Al₂O₃, 1–3 µm synthetic diamond particles and silica coating with 30 µm SiO_x. Fiber posts were cemented to the root canals with adhesive resin cement (Panavia F 2.0). Three slices of 1.5 mm thick were obtained from each root. Push-out tests were performed with a universal testing machine. The data were analyzed with one-way analysis of variance (ANOVA) and Tukey HSD tests (α = 0.05). The effect of the surface treatments were examined under a scanning electron microscope (SEM) and surface roughness were evaluated with a profilometer. Results. Surface pre-treatment methods affected the bond strength (p < 0.05). The highest bond strengths were obtained by air abrasion with synthetic diamond particles, the lowest bond strength were obtained by etching with methylene chloride (p < 0.05). Conclusion. Mechanical surface pre-treatment methods showed higher bond strength values than chemical methods. Synthetic diamond particles may be an alternative method to increase resin cement bonding on the quartz fiber post surfaces.     

不同浓度H2O2的桩表面处理对玻璃纤维桩与树脂水门汀黏结强度的影响

目的：研究不同浓度的H2O2表面处理对纤维桩与树脂水门汀之间黏结强度的影响。方法：选择2种不同种类的玻璃纤维桩各18支,随机分为6组,A组(对照组)、B组(单纯硅烷化处理)、C组(3%H2O2+硅烷化处理)、D组(10%H2O2+硅烷化处理)、E组(20%H2O2+硅烷化处理)和F组(30%H2O2+硅烷化处理)。将各组纤维桩与树脂水门汀进行黏结,形成圆柱状树脂块,将每个树脂块切割成7个1.0 mm厚的薄片进行推出实验,记录数据并采用SPSS13.0软件包对数据进行统计学分析。测试后的试件置于光学显微镜下,观察其破坏模式。结果：Tenax玻璃纤维桩黏结强度值A1-F1组分别为 (22.35±3.43) MPa 、(22.75±1.92) MPa、(27.21±3.60) MPa、(32.32±2.19) MPa、(36.15±2.32) MPa和(40.51±2.37) MPa,Macthpost玻璃纤维桩黏结强度值A2-F2组分别为(17.29±3.23) MPa、(17.01±3.18) MPa、(20.48±2.11) MPa 、(23.60±2.60) MPa 、(27.65±3.77) MPa和(30.52±2.99) MPa。Tenax及Matchpost组中,除了A组和B组无显著差异(P>0.05)外,其余每2组间相比,差异均有显著性(P<0.05)。结论：使用H2O2溶液处理Tenax及Matchpost玻璃纤维桩表面再涂以硅烷偶联剂,可明显提高2种玻璃纤维桩与树脂水门汀之间的黏结强度。30%H2O2溶液处理玻璃纤维桩表面的黏结强度最高,可使其更利于黏结。     

Er:YAG激光不同能量预处理对自粘结树脂水门汀剪切粘结强度的影响

目的探讨Er:YAG激光不同能量预处理对自粘结树脂水门汀剪切粘结强度的影响。方法按照纳入标准收集人离体磨牙70颗,根据对牙本质表面Er:YAG激光预处理能量的不同随机分为7组:A组(空白对照)、B组(50 m J,10 Hz)、C组(100 m J,10 Hz)、D组(150 m J,10 Hz)、E组(200 m J,10 Hz)、F组(250 m J,10 Hz)、G组(300 m J,10 Hz)。每组10颗牙中随机取2颗切取3 mm厚的牙本质片,按相应分组用不同激光能量预处理后扫描电镜观察;每组剩余8颗牙包埋后,制备一致标准牙本质表面,按相应分组要求预处理后,用自粘结树脂水门汀Rely XTMUnicem将其与Everest ZS氧化锆瓷片粘结,24 h后测试各组剪切粘结强度并进行统计学分析。结果扫描电镜观察显示Er:YAG激光预处理后牙本质表面形态改变明显,变得粗糙不平,牙本质小管开放,无玷污层,管周和管间牙本质脱矿,一定能量范围内呈现较好的粘结表面;剪切粘结强度结果显示Er:YAG激光预处理可增强自粘结树脂水门汀Rely XTMUnicem的剪切粘结强度(P<0.01);C、D、E组的剪切粘结强度与A组有显著性差异(P<0.05)。结论粘结强度与牙本质的粘结表面密切相关,合适能量下的Er:YAG激光预处理能获得较好的牙本质粘结表面,提高自粘结树脂与牙本质和氧化锆瓷的剪切粘结强度。     

Influence of cement thickness on the bond strength of tooth-colored posts to root dentin after thermal cycling

Abstract

Objective. The purpose of this study was to evaluate the effect of different resin cement thickness on the push-out bond strength of different posts (CAD/CAM zirconia post (ZR post)) and an individually formed glass fiber reinforced composite post (IPN post) prior to and after thermal cycling (TC). Methods. Post spaces with a height of 9 mm and a diameter of 1.5 mm were drilled in 80 mandibular premolar teeth. Two groups (n = 40) were formed according to the posts used (IPN posts or ZR posts). Then the specimens were randomly assigned into two sub-groups according to the post diameter: (1) 1.5 mm in diameter and (2) 1.2 mm in diameter (n = 20/per group). All posts were luted with a self-adhesive luting agent according to the manufacturer's instructions by using endo tips. Half of the samples (n = 10) were submitted to thermal cycling (5000 cycles, 5–55°C). Thereafter, four 2-mm thick horizontal sections were obtained and subjected to push-out test. Failure modes were assessed quantitatively and morphologically. The data were statistically analyzed with a three-way analysis of variance (ANOVA) (p < 0.05). Statistical differences in failure modes were investigated by chi-square tests at a significance level of p < 0.05. Result. Push-out bond strengths were significantly influenced both by the post diameter and thermal cycling. Larger (1.5 mm) diameter post results were statistically higher than 1.2 mm results (p < 0.05). Moreover, TC significantly increased the bond strength results (p < 0.05). There was no significant difference between ZR and IPN posts (p = 0.219). Conclusion. The bond strengths of ZR and IPN posts were significantly decreased when the resin cement layer was thick. In addition, thermal cycling drastically influenced bond strengths of the tested post materials. Clinical significance: The fit between tooth-colored endodontic posts and post spaces should be as tight as possible.     

The effect of the application of gaseous ozone and ND:YAG laser on glass‐fibre post bond strength

The aim of this study was to investigate the effects of the application of gaseous ozone and Nd:YAG laser on glass‐fibre post bond strength. Forty‐two madibular premolar roots were cut, endodontically instrumented and irrigated with 2.5% NaOCl. Post spaces were prepared and roots were divided into three groups (n = 14). The antimicrobial pretreatment was conducted as follows: gaseous ozone, Nd:YAG laser and control (no additional disinfection methods). Scanning electron microscope analysis was made for each group (n = 2). A resin cement was used for luting the posts. For push‐out test, each root was cut horizontally (two cervical, two middle and two apical). Statistical analyses were performed with one‐way anova (α = 0.05). Fracture types were observed. There was no statistically significant difference between the groups (P > 0.05). There were statistically significant differences in cervical and apical segments of laser and control groups (P < 0.05). The disinfection of the post spaces with Nd:YAG laser and ozone had no adverse effects on bond strength of glass‐fibre post.     

The effect of different power outputs of carbon dioxide laser on bonding between zirconia ceramic surface and resin cement

Abstract

Objective. The purpose of this in vitro study was to evaluate the influence of different power outputs of a carbon dioxide (CO2) laser on shear bond strength of resin cement to zirconium dioxide-based ceramic. Materials and methods. Fifty zirconium dioxide core specimens (10 mm diameter and 2 mm thickness) were produced and they were embedded in the centers of auto-polymerizing acrylic resin blocks. Ten specimens served as control and no surface treatment was applied. Subsequently specimens were randomly divided into four groups, each containing 10 specimens for surface treatment with CO2 laser with different output power; laser treated with 2 W (Group 2 W), 3 W (Group 3 W), 4 W (Group 4 W) and finally 5 W (Group 5 W). Fifty composite resin discs were fabricated and cemented with adhesive resin cement to the specimen surfaces. A universal test machine was used for shear bond strength test at a crosshead speed 1 mm/min. Data were statistically analyzed by one-way analyses of variance (ANOVA) with Post-Hoc Tukey tests (α = 0.05). Results. It was found that the shear bond strength values were affected by power outputs of laser (p < 0.05). Highest shear bond strength values were obtained with group 2 W (21.0 ± 2.7). Lowest values were obtained with group 5 W (14.4 ± 1.6). Conclusion. The current study revealed that there was a relationship between laser output power and shear bond strength for zirconium dioxide ceramics. However, output power of the laser and the energy level is a critical factor on micromechanical retention.     

玻璃纤维桩表面不同处理方法对粘接强度的影响

目的 评价表面处理方法对玻璃纤维桩粘接强度的影响.方法 选用MATCHPOST玻璃纤维桩和Relyx玻璃纤维桩各16根,按照表面处理方法随机分为4组:对照组(无表面处理);单独硅烷偶联剂处理组;单独粘接剂处理组;硅烷偶联剂+粘接剂联合处理组,每组每种纤维桩4根.用树脂水门汀将纤维桩粘接就位至圆筒模具,再用自凝塑料包埋.37C蒸馏水水浴24h后从垂直于纤维桩长轴的方向将样本从底部切割2个1 mm薄片.对64个薄片进行微推出测试.所得数据用SPSS19.0统计软件进行分析.结果 MATCHPOST玻璃纤维桩四组中,硅烷偶联剂+粘接剂联合处理组的粘接强度最高,与对照组相比差异具有统计学意义(P＜0.05),与单独粘接剂处理组相比统计学上具有非常显著差异(P＜0.01);其他各组间差异无统计学意义(P＞0.05).Relyx玻璃纤维桩四组中,硅烷偶联剂+粘接剂联合处理组粘接强度最高,但各组间差异无统计学意义(P＞0.05).结论 硅烷偶联剂和粘接剂联合处理后可以增强玻璃纤维桩与树脂水门汀的粘接强度.     

Tensile bond strength of glass fiber posts luted with different cements

Proper selection of the luting agent is fundamental to avoid failure due to lack of retention in post-retained crowns. The objective of this study was to investigate the tensile bond strength and failure mode of glass fiber posts luted with different cements. Glass fiber posts were luted in 40 mandibular premolars, divided into 4 groups (n = 10): Group 1--resin-modified glass ionomer RelyX Luting; Group 2--resin-modified glass ionomer Fuji Plus; Group 3--resin cement RelyX ARC; Group 4--resin cement Enforce. Specimens were assessed by tensile strength testing and light microscopy analysis for observation of failure mode. The tensile bond strength values of each group were compared by ANOVA and Tukey test. The significance level was set at 5%. The failure modes were described as percentages. The following tensile strength values were obtained: Group 1--247.6 N; Group 2--256.7 N; Group 3--502.1 N; Group 4--477.3 N. There was no statistically significant difference between Groups 1 and 2 or between Groups 3 and 4, yet the resin cements presented significantly higher tensile bond strength values than those presented by the glass ionomer cements. Group 1 displayed 70% of cohesive failures, whereas Groups 2, 3 and 4 exhibited 70% to 80% of adhesive failures at the dentin-cement interface. We concluded that resin cements and glass ionomer cements are able to provide clinically sufficient retention of glass fiber posts, and that glass ionomer cements may be especially indicated when the application of adhesive techniques is difficult.     

Evaluation of the surface roughness of zirconia ceramics after different surface treatments

Objective. This study aimed to investigate the effects of different mechanical surface treatments of pre-sintered zirconium oxide (ZrO₂) in an attempt to improve its bonding potential. Materials and methods. One hundred and twenty IPS e-max ZirCAD (Ivoclar Vivadent) pre-sintered zirconia blocks (7 mm diameter, 3 mm height) received six different surface treatments (n = 20): Group C was untreated (control); Group E was Er:YAG laser irradiated; Group N was Nd:YAG laser irradiated; Group SB was sandblasted, Group SN was sandblasted and Nd:YAG laser irradiated; and Group SE was sandblasted and Er:YAG laser irradiated. After the surface treatments, the average surface roughness (Ra, µm) of each specimen was determined with a profilometer, then all the specimens were sintered. The surface roughness values were analysed through one-way ANOVA and Tukey's test. Changes in the morphological characteristics of ZrO₂ were examined through scanning electron microscopy (SEM). Results. Sintered sandblasted, Er:YAG laser treatment, sandblasted + Er:YAG laser and sandblasted + Nd:YAG laser irradiation resulted in a rougher surface than the other treatments. Conclusion. Nd:YAG laser irradiation alone was not effective in altering the zirconia surface morphology.     

Impact of different surface treatment methods on bond strength between fiber post and composite core material

PurposeTo assess the impact of different surface treatments on the push-out bond strength between fiber post and a composite resin core material.Material and methodsSeventy-two glass-fiber posts were randomly assigned into six groups according to the method of surface treatment: Control (no treatment), silane, sandblasting, hydrofluoric acid, hydrogen peroxide, and hydrogen peroxide with sandblasting. Two posts from each group were inspected under a scanning electron microscope to assess the surface modifications and 10 posts were employed for the push-out test. Each post was placed vertically in the middle of a cylindrical putty matrix and a dual-cure composite resin material was applied for core build-up. Two discs of each specimen were cut using a low-speed diamond saw (total 120 discs). The push-out test was executed using a universal testing machine at a crosshead speed of 0.5 mm/min. Statistical analysis was performed using one-way ANOVA and Tukey’s test (p ≤ 0.05). The mode of failure of each disc was evaluated under SEM.ResultsThe sandblasting and hydrofluoric acid groups presented significantly higher bond strength than control and hydrogen peroxide groups. The hydrogen peroxide groups exhibited significantly the lowest bond strength of all groups. There was no significant difference between the control and silane groups. All groups showed predominantly adhesive failure except the hydrogen peroxide with sandblasting, where the cohesive failure of the post was predominant.ConclusionsSandblasting and hydrofluoric acid surface treatments demonstrated superior results to silane and hydrogen peroxide. The combined method of hydrogen peroxide and sandblasting could weaken the fiber post and lead to clinical fractures.     

Bond strength of fiber posts after the application of erbium:yttrium-aluminum-garnet laser treatment and gaseous ozone to the root canal

The aim of the present study was to investigate the effects of antibacterial agents (erbium:yttrium-aluminum-garnet [Er:YAG] laser or gaseous ozone) intended to disinfect root canals on bond strengths of fiber posts compared with canals that were finally irrigated using chlorhexidine (CHX). One hundred forty-four human anterior teeth were divided into three groups (n = 48); root canal instrumentation was performed, and antimicrobial pretreatment was conducted as follows: control group: CHX, group 2: Er:YAG laser, and group 3: gaseous ozone. In all groups, fiber posts were inserted using Panavia F 2.0 (Kuraray, Osaka, Japan), Variolink II (Ivoclar Vivadent, Schaan, Liechtenstein), RelyX Unicem (3M Espe; Seefeld, Germany), or Ketac Cem (3M Espe) (n = 12 each). Push-out bond strengths to root canal dentin were affected by the type of luting agent but not by the antimicrobial pretreatment regimen. However, significant interactions between the luting agent and pretreatment could be observed, and adhesion of the self-adhesive resin cement RelyX Unicem was significantly reduced after using gaseous ozone.     

H2O2溶液表面处理对纤维桩和树脂水门汀粘接强度的影响

目的 评价不同浓度H2O2溶液表面处理对玻璃纤维桩与树脂水门汀粘接强度的影响。方法 将25支POPO纤维桩随机分成5组：A组（对照组）,B组（硅烷组）,C组（10% H2O2+硅烷组）,D组（20% H2O2+硅烷组）,E组（30% H2O2+硅烷组）。将纤维桩与树脂水门汀粘接制作树脂块及薄片试件,将试件放在万能试验机上加载后算出粘接强度,体视显微镜观察破坏模式,统计学分析。结果 各组粘接强度值为：A组 （12.36±1.66）MPa,B组（12.76±1.59）MPa,C组（16.10±2.55）MPa,D组（19.19±2.81）MPa,E组（21.95±2.95） MPa。5组数据两两比较,除AB组比较无统计学意义（P>0.05）,其余均有统计学意义（P<0.05）。结论 仅用硅烷偶联剂对玻璃纤维桩进行表面处理的粘接强度并未提高;H2O2溶液处理后再涂硅烷偶联剂可提高玻璃纤维桩与树脂水门汀的粘接强度,随H2O2溶液浓度的增加,粘接强度增加增多。