Effect of endodontic sealer and resin luting strategies on pull-out bond strength of glass fiber posts to dentin

The aim of this study was to evaluate the influence of eugenol-containing endodontic sealers and luting strategy on the pull-out bond strength of glass fiber posts to dentin. Sixty-four bovine incisors were randomly assigned into two groups of 32 specimens each for obturation procedure with gutta-percha only, or with Pulp Canal Sealer EWT Subsequently, the roots were prepared for the fiber post Reforpost and all specimens of each endodontic sealing procedure were allocated to four groups (n = 8), according to the strategies for post cementation: A) Single Bond 2 and RelyX ARC; B) All Bond 2 and C&B cement; C) All Bond 2 and RelyX ARC; D) Single Bond 2 and C&B Cement. The posts were cemented immediately after the endodontic treatment. The pull-out test was performed at a cross-head speed of 0.5 mm/min in a universal testing machine (EMIC). Data (Kgf) were submitted to a two-way ANOVA and Tukey test (p < or = 0.05). The eugenol-based sealer did not influence the pull-out bond strength of fiber posts regardless of the luting strategy. RelyX ARC showed higher bond strength than C&B Cement when used with Single Bond 2 adhesive system, when the eugenol-based sealer was present. All Bond 2, when associated to all cements studied, promoted similar bond strength, regardless of the eugenol-containing endodontic sealer In conclusion, eugenol-containing sealer did not influence the pull-out bond strength values of the resin luting systems for glass fiber post cementation. The bond system and resin cement association from the same manufacturer had similar bond strength values for dentin.     

Finite element analysis and bond strength of a glass post to intraradicular dentin: Comparison between microtensile and push-out tests

OBJECTIVE: This study tested the hypothesis that the stress distribution and bond strength of glass posts to intraradicular dentin is influenced by the mechanical testing methodology. METHODS: Thirty single rooted endodontically treated teeth were prepared for luting of tapered fiber-glass posts (Reforpost, Angelus, Londrina, PR, Brazil) with a conventional adhesive system and resin luting cement (Adper Scotchbond Multi-purpose, Rely X ARC, 3M ESPE, St. Paul, MN, USA). The teeth were randomly divided (n=10 per group) into micro-push-out (Mpo), hourglass- (Mh) and rectangular stick-shaped (Ms) microtensile testing groups before sectioning each root into five 1-mm-thick specimens. During specimen preparation for muTBS testing 46/50 stick and 4/50 hourglass specimens prematurely failed; therefore, the Ms group could not be included in the mechanical testing. The remaining specimens were tested at 0.5mm/min until bond failure. Stress distribution within each specimen type for the three mechanical test methods was analyzed by finite element analysis (FEA). Qualitative analyses were carried out through Von Mises, XY and Sy criterion. RESULTS: Mpo and Mh had a mean muTBS of 11.89+/-6.55 and 14.98+/-12.72MPa, respectively, which was not significantly different (p=0.1311). The push-out test demonstrated a more homogenous stress distribution by FEA and less variability in mechanical testing. SIGNIFICANCE: Therefore, the recommended testing method for determining the bond strength of glass posts to intraradicular dentin is by Mpo.     

Short resin-posts bonding to primary dentin. Microleakage and micro-morphological in vitro study

The aim of this in vitro study was to evaluate the adhesion of two bonding systems (Single Bond and Adper Prompt L Pop, 3M ESPE) to short resin posts in the root dentin of primary teeth. Statistical analysis (Mann Whitney) revealed that there were no statistically significant differences between the materials (p= 0.75), but the Single Bond group presented a wider resin-dentin inter-diffusion zone (RDIZ). Both groups showed long resin tags. It was concluded that although Single Bond produced a wider adhesive interface than Adper Prompt L Pop, leakage levels occurred in both systems.     

Bonding of dual-curing resin cements to dentin

PURPOSE: The purpose of the study was three-fold: 1) to determine the strength of the bond between a number of dual-curing resin cements and dentin treated with corresponding adhesive systems, 2) to determine the effect on bond strength of not light curing the cements, and 3) to investigate whether application of a solution of sodium sulfinate or ascorbic acid would increase the bond strength in the cases where the manufacturer's version of an adhesive system resulted in low bond strength with chemically cured cement, ie, cement cured without light. MATERIALS AND METHODS: The adhesive systems comprised 5 simplified systems (Adper Scotchbond 1 XT, ED Primer II, Excite DSC, OptiBond Solo Plus, and Prime and Bond NT), and as controls, two three-step etch and rinse systems (Adper Scotchbond Multi-Purpose Plus and Gluma Solid Bond). The corresponding dual-curing resin cements were RelyX ARC, Panavia F 2.0, Variolink II, Nexus 2, Calibra, RelyX ARC, and 2Bond2. The cements were either light and chemically cured or only chemically cured. The adhesive systems were used as recommended by the manufacturers, which for some systems involved inclusion of a so-called activator or catalyst when used with chemically cured cement. Sodium sulfinate and ascorbic acid were applied as a 1% ethanol solution. The bond strengths were measured in shear after storing specimens for 24 h in 37 degree C water. RESULTS: When the dual-curing resin cements had been both light and chemically cured, the bond strengths increased in this order: Gluma Solid Bond < ED Primer II < Prime and Bond NT < Adper Scotchbond Multi-Purpose Plus < Excite DSC < Adper Scotchbond 1 XT < OptiBond Solo Plus. Omission of light curing of the cements decreased the bond strengths with OptiBond Solo Plus and Prime and Bond NT. The use of activator in conjunction with OptiBond Solo Plus and Prime and Bond NT increased the bond strength to chemically cured cement, but not to the level obtained when the cement was both light and chemically cured. The use of the catalyst of Adper Scotchbond Multi-Purpose Plus did not increase the bond strength with chemically cured cement. Pretreatment with a solution of sodium sulfinate or ascorbic acid increased the bond strength with chemically cured cement in the case of OptiBond Solo Plus, whereas only the solution of sodium sulfinate was effective with Prime and Bond NT. CONCLUSION: Clinicians should be aware that in situations where a dual-curing resin cement cannot be light cured, some adhesive systems suffer a loss of efficacy, even when respective activators are used. Pretreatment with a 1% ethanol solution of sodium sulfinate may restore much of the lost bond strength.     

EFFECT OF AN ADDITIONAL HYDROPHILIC VERSUS HYDROPHOBIC COAT ON THE QUALITY OF DENTINAL SEALING PROVIDED BY TWO-STEP ETCH-AND-RINSE ADHESIVES

Objective:

To test the hypothesis that the quality of the dentinal sealing provided by two-step etch-and-rinse adhesives cannot be altered by the addition of an extra layer of the respective adhesive or the application of a more hydrophobic, non-solvated resin.

Material and Methods:

full-crown preparations were acid-etched with phosphoric acid for 15 s and bonded with Adper Single Bond (3M ESPE), Excite DSC (Ivoclar/Vivadent) or Prime & Bond NT (Dentsply). The adhesives were used according to the manufacturers'' instructions (control groups) or after application to dentin they were a) covered with an extra coat of each respective system or b) coated with a non-solvated bonding agent (Adper Scotchbond Multi-Purpose Adhesive, 3M ESPE). Fluid flow rate was measured before and after dentin surfaces were acid-etched and bonded with adhesives.

Results:

None of the adhesives or experimental treatments was capable to block completely the fluid transudation across the treated dentin. Application of an extra coat of the adhesive did not reduce the fluid flow rate of adhesive-bonded dentin (p>0.05). Conversely, the application of a more hydrophobic non-solvated resin resulted in significant reductions in the fluid flow rate (p<0.05) for all tested adhesives.

Conclusions:

The quality of the dentinal sealing provided by etch-and-rinse adhesives can be significantly improved by the application of a more hydrophobic, non-solvated bonding agent.     

The effect of different adhesive system applications on push-out bond strengths of glass fiber posts

PURPOSE

Over the past years, the adhesion of fiber posts luted with simplified adhesive systems has been a matter of great interest. The aim of this study was to assess the post retentive potential of a self-adhesive resin cement using different adhesive systems to compare the push-out bond strengths of fiber posts.

MATERIALS AND METHODS

The post spaces of 56 mandibular premolar roots were prepared and divided into 4 experimental groups and further divided into 2 subgroups according to testing time (n=7). The fiber posts (Rely X Fiber Post) were luted with a self-adhesive resin cement (RelyX Unicem) and one of the following adhesive systems: no adhesive, a total-etch adhesive resin (Single Bond), a two-step self-etch adhesive resin (Clearfil SE Bond) and a one-step self-etch adhesive resin (Clearfil S3 Bond). Each root was cut horizontally, and 1.5 mm thick six root segments were prepared. Push-out tests were performed after one week or three months (0.5 mm/min). Statistical analysis were performed with three-way ANOVA (α=.05).

RESULTS

Cervical root segments showed higher bond strength values than middle segments. Adhesive application increased the bond strength. For one week group, the total-etch adhesive resin Single Bond showed higher bond strength than the self-adhesive resin cement RelyX Unicem applied without adhesive resin at middle region. For 3 months group, the two-step self-etch adhesive resin Clearfil SE Bond showed the highest bond strength for both regions. Regarding the time considered, Clearfil SE Bond 3 months group showed higher bond strength values than one week group.

CONCLUSION

Using the adhesive resins in combination with the self-adhesive resin cement improves the bond strengths. The bond strength values of two-step self-etch adhesive resin Clearfil SE Bond improved as time passes.     

Effect of various intraoral repair systems on the shear bond strength of composite resin to zirconia

PURPOSE

This study compared the effect of three intraoral repair systems on the bond strength between composite resin and zirconia core.

MATERIALS AND METHODS

Thirty zirconia specimens were divided into three groups according to the repair method: Group I- CoJet™ Repair System (3M ESPE) [chairside silica coating with 30 µm SiO₂ + silanization + adhesive]; Group II- Ceramic Repair System (Ivoclar Vivadent) [etching with 37% phosphoric acid + Zirconia primer + adhesive]; Group III- Signum Zirconia Bond (Heraus) [Signum Zirconia Bond I + Signum Zirconia Bond II]. Composite resin was polymerized on each conditioned specimen. The shear bond strength was tested using a universal testing machine, and fracture sites were examined with FE-SEM. Surface morphology and wettability after surface treatments were examined additionally. The data of bond strengths were statistically analyzed with one-way ANOVA and Tamhane post hoc test (α=.05).

RESULTS

Increased surface roughness and the highest wettability value were observed in the CoJet sand treated specimens. The specimens treated with 37% phosphoric acid and Signum Zirconia Bond I did not show any improvement of surface irregularity, and the lowest wettability value were found in 37% phosphoric acid treated specimens. There was no significant difference in the bond strengths between Group I (7.80 ± 0.76 MPa) and III (8.98 ± 1.39 MPa). Group II (3.21 ± 0.78 MPa) showed a significant difference from other groups (P<.05).

CONCLUSION

The use of Intraoral silica coating system and the application of Signum Zirconia Bond are effective for increasing the bond strength of composite resin to zirconia.     

Does bonding to dentin reduce microleakage of composite restorations?

This study evaluated the effect of adhesive application only to enamel on the marginal microleakage of composite resin restorations performed with different adhesive systems. Standardized cylinder-shaped cavities were prepared on the buccal surface of eighty bovine incisors. Two etch-and-rinse (Adper Scotchbond Multi-purpose [3M ESPE, St. Paul, MN USA] and Adper Single Bond 2 [3M ESPE]) and two self-etching (Clearfil SE Bond [Kuraray, Osaka, Japan] and Adper Prompt [3M ESPE]) adhesive systems were evaluated. The adhesives were applied only to enamel or to both dentin and enamel. After adhesive light-activation, the cavities were restored with composite resin. The samples were coated with two layers of nail polish, except an area of 1-mm wide around of the restoration, and immersed in a methylene blue solution. Afterwards, the specimens were ground in order to obtain powder which was immersed in absolute alcohol. The solutions were centrifuged and the supernatant was analyzed using an absorbance spectrophotometer. Linear regression was used to estimate the dye concentration. Data were analyzed using ANOVA and Tukey's tests (alpha = 0.05). The etch-and-rinse adhesives showed lower microleakage means compared to those of the self-etching adhesives. Adper Prompt presented higher microleakage means. There was no difference between the modes of application of the adhesive on the cavity for all adhesive systems, except for Clearfil SE Bond. This showed lower microleakage when applied to the whole cavity. Bonding to dentin may not reduce microleakage of composite restorations.     

Effect of Mineral Trioxide Aggregate Surface Treatments on Morphology and Bond Strength to Composite Resin

Introduction

The aim of this study was to evaluate the micromorphologic changes that accompany different surface treatments on mineral trioxide aggregate (MTA) and their effect on the bond strength to the composite resin with 4 adhesive systems.

Methods

Three types of MTA cement, ProRoot MTA (WMTA) (Dentsply, Tulsa, OK), MTA Angelus (AMTA) (Angelus, Londrina, PR, Brazil), and Endocem MTA (EMTA) (Maruchi, Wonju, Korea), were prepared and stored for a week to encourage setting. Surface treatment was performed using phosphoric acid or self-etch primer, and an untreated MTA surface was prepared as a control. The surface changes were observed using scanning electron microscopy. MTA surfaces were bonded with 4 adhesive systems, including Scotchbond Multipurpose (3M ESPE, St Paul, MN), Single Bond 2 (3M ESPE), Clearfil SE BOND (Kuraray, Osaka, Japan), and AdheSE One F (Ivoclar Vivadent, Schaan, Liechtenstein), to evaluate the adhesive effectiveness of MTA followed by composite resin restoration. The shear bond strength of the polymerized specimens was tested.

Results

For WMTA and AMTA, untreated surfaces showed an irregular crystalline plate with clusters of globular aggregate particles. For EMTA, the untreated surface presented a reticular matrix with acicular crystals. After surface treatment, superficial crystalline structures were eroded regardless of the MTA cement and adhesive system used. WMTA bonded significantly more strongly than AMTA and EMTA, regardless of the adhesive system used. In the WMTA and AMTA groups, AdheSE One F showed the highest bond strength to the composite. For EMTA, no significant differences were found across adhesive systems.

Conclusions

Acidic treatment of the MTA surface affected the micromorphology and the bond strength to the composite. Within the limitations of this study, using a 1-step self-etch adhesive system might result in a strong bond to WMTA when the composite resin restoration is required over MTA cement.     

Effect of cavity configuration and aging on the bonding effectiveness of six adhesives to dentin.

OBJECTIVES: The purpose of this study was to determine the effect polymerization contraction stress may have on bond durability. METHODS: Bonding effectiveness was assessed by micro-tensile bond strength testing (muTBS) and electron microscopy. The muTBS to flat dentin surfaces and in standardized cavities was determined (this after 1 day as well as 1 year water storage). Six adhesives representing all current classes were applied: two etch-and-rinse (OptiBond FL, Kerr; Scotchbond 1, 3M ESPE), two self-etch (Clearfil SE Bond, Kuraray; Adper Prompt, 3M ESPE) and two glass-ionomer (Fuji Bond LC, GC; Reactmer, Shofu) adhesives. RESULTS: The conventional 3-step etch-and-rinse adhesive OptiBond FL bonded most effectively to dentin, and appeared insensitive to polymerization shrinkage stress and water degradation. The 2-step self-etch adhesive Clearfil SE Bond most closely approached this superior bonding effectiveness and only slightly lost bond strength after 1-year water exposure. The 2-step etch-and-rinse adhesive Scotchbond 1 and the 'strong' 1-step self-etch adhesive Adper Prompt appeared very sensitive to cavity configuration and water-aging effects. The 2-step resin-modified glass-ionomer adhesive Fuji Bond LC only suffered from shrinkage stress, but not from 1-year water-exposure. Remarkable also is the apparent repairability of the 'mild' 1-step glass-ionomer adhesive Reactmer when stored for 1 year in water, in spite of the very low 1-day muTBS. SIGNIFICANCE: Simplified bonding procedures do not necessarily imply improved bonding performance, especially in the long term.     

Microtensile bond strength of photoactivated and autopolymerized adhesive systems to root dentin using translucent and opaque fiber-reinforced composite posts

STATEMENT OF PROBLEM: The use of fiber-reinforced composite resin posts in endodontically treated teeth has increased. However, selecting an adhesive system that provides reliable and long-lasting bonding to root canal dentin remains difficult. PURPOSE: This study evaluated the microtensile bond strength of 2 adhesive systems to root dentin and 2 different fiber-reinforced composite resin posts. MATERIAL AND METHODS: Forty single-rooted teeth were instrumented, and root canals were prepared for translucent (Light Post [LP]) or opaque (Aestheti Post [AP]) quartz fiber-reinforced composite resin posts. Two adhesive systems were used: Scotchbond Multi-Purpose Plus (SBMP) (autopolymerized) as a control group, and Single Bond (SB) (photoactivated). Teeth were assigned to 4 groups (n=10): SBMP+LP, SBMP+AP, SB+LP, SB+AP. After post cementation, roots were perpendicularly sectioned into 1-mm-thick slices, which were trimmed to obtain dumbbell-shaped specimens. The specimens were divided into 3 regions: cervical (C), middle (M), and apical (A). To determine the bond strength, the bonding area of each specimen was calculated, and specimens were attached to a device to test microtensile strength at a crosshead speed of 1 mm/min. Data were analyzed using 3-way analysis of variance and the Tukey test (alpha=.05). Fractured specimens were examined under a x 25 stereomicroscope to determine the mode of fracture. RESULTS: There were significant differences only among root dentin regions (P<.001). The cervical third (9.16 +/- 1.18 MPa) presented higher mean bond strength values, especially for SBMP. Middle and apical regions demonstrated lower values (7.08 +/- 0.92 and 7.31 +/- 0.60 MPa, respectively). Adhesive and post main factors did not demonstrate significance. Also, no interaction was significant. No cohesive fractures within resin cement, fiber-reinforced composite resin post, or root dentin were identified. CONCLUSIONS: Both adhesive systems tested demonstrated reliable bonding when used with translucent and opaque fiber-reinforced composite posts.     

Influence of endodontic post type (glass fiber, quartz fiber or gold) and luting material on push-out bond strength to dentin in vitro.

OBJECTIVES: To determine the influence of post type and luting material on bond strength to dentin. METHODS: The root canals of extracted human upper central incisors were instrumented and post space was prepared using the respective drills for each post system. Glass fiber posts (Luscent Anchor, Dentatus [LA]) were luted using three dual-curing adhesive systems (Excite DSC/Variolink II, Vivadent [VL2]; EnaBond/EnaCem, Micerium [ENA]; Prime & Bond NT/Calibra, DentSply DeTrey [CAL]). A different brand of glass fiber post (EasyPost, DentSply Maillefer [EP]) and quartz fiber post (DT Light Post, VDW [DT]) were luted using CAL. Gold posts (Perma-dor, VDW) were luted either adhesively following tribo-chemical silicate coating (Rocatec, ESPE-Sil, 3M ESPE; CAL) or conventionally using glass ionomer cement (Ketac Cem, 3M ESPE). Three slices of 2mm height were cut perpendicular to the post from each restored root. Bond strength was determined by pushing out the post using a universal testing machine (/1449, Zwick). RESULTS: For all experimental groups combined, bond strength increased from the coronal to the apical section (Friedman test: P<0.001). Significant differences were observed among the fiber posts (DT/CAL>LA/CAL; Mann-Whitney U-test with Bonferroni-Holm adjustment: P<0.05; EP/CAL ranging in between) but not among luting materials (LA/VL2, LA/ENA, LA/CAL: n.s.). The gold posts were equivalent to DT/CAL with both luting procedures. SIGNIFICANCE: Selection of post type may be more important for bond strength than luting material. Bond strength of fiber posts was equivalent but not superior to adhesively or conventionally luted gold posts.     

EFFECT OF A BONDING RESIN LAYER ASSOCIATED WITH A SELF-ETCHING ADHESIVE SYSTEM ON THE BOND STRENGTH OF INDIRECT RESTORATIONS

The aim of this study was to evaluate the influence of a low-viscosity bonding resin applied over a self-etching adhesive system on the microtensile bond strength (μTBS) of indirect restorations. Comparisons were made using One Up Bond F (OB) self-etching adhesive system, Single Bond (SB) one-bottle adhesive system and Scotchbond Multi Purpose Plus (SMP) bonding component. Thirty bovine incisors were extracted and decoronated at the cementoenamel junction. The labial surfaces were ground so that superficial dentin and deep dentin were exposed. The specimens were randomized to three groups (n=10): G1- OB; G2- OB + SMP; G3- SB. In G2, a layer of the SMP bonding was applied over the OB adhesive system. Indirect composite restorations were bonded using dual-cure cement under 500 g load for 5 min. The specimens were serially sectioned with a bonding area of ± 1.0 mm² in 3 regions: enamel (E), superficial dentin (SD) and deep dentin (DD). The sticks were fixed with cyanoacrylate adhesive and submitted to μTBS test at a crosshead speed of 0.5 mm/min in a mechanical testing machine (EMIC DL 2000). The fractured specimens were examined under scanning electron microscopy to determine the failure mode. Data were analyzed by one-way ANOVA followed by Tukey''s test (p<0.05). μTBS means (in MPa) were: G1/E: 15.5 ± 3.5b; G1/SD: 22.7 ± 7.6a; G1/DD: 19.4 ± 9.4a; G2/E: 15.9 ± 5.8b; G2/SD: 19.9 ± 6.9a; G2/DD: 15.3 ± 4.9a; G3/E: 23.2 ± 7.3a; G3/SD: 20.4 ± 8.2a; G3/DD: 19.1 ± 8.7a. The results showed that the use of a low viscosity bonding resin did not affect the μTBS means when associated with a self-etching adhesive system. The self-etching adhesive system was significantly more efficient in dentin than in enamel, while the one-bottle system was significantly more efficient in enamel when compared to the self-etching adhesive system.     

BOND STRENGTH AND MORPHOLOGY OF ENAMEL USING SELF-ETCHING ADHESIVE SYSTEMS WITH DIFFERENT ACIDITIES

Objectives:

To assess the bond strength and the morphology of enamel after application of self-etching adhesive systems with different acidities. The tested hypothesis was that the performance of the self-etching adhesive systems does not vary for the studied parameters.

Material and methods:

Composite resin (Filtek Z250) buildups were bonded to untreated (prophylaxis) and treated (burcut or SiC-paper) enamel surfaces of third molars after application of four self-etching and two etch-and-rinse adhesive systems (n=6/condition): Clearfil SE Bond (CSE); OptiBond Solo Plus Self-Etch (OP); AdheSe (AD); Tyrian Self Priming Etching (TY), Adper Scotchbond Multi-Purpose Plus (SBMP) and Adper Single Bond (SB). After storage in water (24 h/37°C), the bonded specimens were sectioned into sticks with 0.8 mm² cross-sectional area and the microtensile bond strength was tested at a crosshead speed of 0.5 mm/min. The mean bond strength values (MPa) were subjected to two-way ANOVA and Tukey''s test (α=0.05). The etching patterns of the adhesive systems were also observed with a scanning electron microscope.

Results:

The main factor adhesive system was statistically significant (p<0.05). The mean bond strength values (MPa) and standard deviations were: CSE (20.5±3.5), OP (11.3±2.3), AD (11.2±2.8), TY (11.1±3.0), SBMP (21.9±4.0) and SB (24.9±3.0). Different etching patterns were observed for the self-etching primers depending on the enamel treatment and the pH of the adhesive system.

Conclusion:

Although there is a tendency towards using adhesive systems with simplified application procedures, this may compromise the bonding performance of some systems to enamel, even when the prismless enamel is removed.     

Knoop Hardness and Effectiveness of Dual‐Cured Luting Systems and Flowable Resin to Bond Leucite‐Reinforced Ceramic to Enamel

Purpose: The aim of this study was to evaluate the Knoop microhardness and microshear bond strength (MSBS) of dual‐cured luting systems and flowable resin bonded to leucite‐reinforced ceramics and enamel. Materials and Methods: Eighty bovine incisors were randomly divided into four groups per test (microhardness and microshear; n = 10) according to the bonding procedure: Excite DSC/Variolink, Clearfil SE Bond/Panavia F, Adper Scotchbond Multi‐Purpose Plus/RelyX ARC, and Adper Single Bond 2/Filtek Z350 Flow. For the KHN measurement, the cement was applied on the enamel surface and light‐cured through a ceramic disk (5 mm diameter × 1.2 mm thick). Five indentations were performed in each specimen and measured at HMV‐2. For the microshear test, two cylinders of a leucite‐reinforced ceramic (1 mm diameter × 2 mm height) were bonded to the enamel substrate in accordance with the bonding procedures previously established. One cylinder was tested 24 hours after cementation, and the other was subjected to thermocycling (2000 cycles) and then submitted to an MSBS test. The data from the hardness and bond strength tests were subjected to one‐ and two‐way repeated‐measures analysis of variance (ANOVA), respectively, and to Tukey's test (α= 0.05). Results: Scotchbond/RelyX ARC presented higher values of bond strength, while Single Bond/Z350 Flow showed lower values. The thermocycling promoted a reduction in the bond strength values for all groups. Panavia F presented higher values of KHN, and the flowable resin presented the lowest. RelyX ARC and Variolink presented intermediate values on hardness evaluation. Conclusions: For ceramic cementation, dual‐cured resin luting systems promoted more reliable bonding and microhardness values than the flowable resin.     

Microshear bond strength of resin composite to teeth affected by molar hypomineralization using 2 adhesive systems

PURPOSE: When restoring hypomineralized first permanent molars, placement of cavo-surface margins can be difficult to ascertain due to uncertainty of the bonding capability of the tooth surface. The purpose of this study was to investigate the adhesion of resin composite bonded to control and hypomineralized enamel with an all-etch single-bottle adhesive or self-etching primer adhesive. METHODS: Specimens of control enamel (N=44) and hypomineralized enamel (N=45) had a 0.975-mm diameter composite rod (Filtek Supreme Universal Restorative) bonded with either 3M ESPE Single Bond or Clearfil SE Bond following manufacturers' instructions. Specimens were stressed in shear at 1 mm/min to failure (microshear bond strength). Etched enamel surfaces and enamel-adhesive interfaces were examined under scanning electron microscopy. RESULTS: The microshear bond strength (MPa) of resin composite bonded to hypomineralized enamel was significantly lower than for control enamel (3M ESPE Single Bond=7.08 +/- 4.90 vs 16.27 +/- 10.04; Clearfil SE Bond=10.39 +/- 7.56 vs 19.63 +/- 7.42; P=.001). Fractures were predominantly adhesive in control enamel and cohesive in hypomineralized enamel. Scotchbond etchant produced deep interprismatic and intercrystal porosity in control enamel and shallow etch patterns with minimal intercrystal porosity in hypomineralized enamel. Control enamel appeared almost unaffected by SE Primer; hypomineralized enamel showed shallow etching. The hypomineralized enamel-adhesive interface was porous with cracks in the enamel. The control enamel-adhesive interface displayed a hybrid layer of even thickness. CONCLUSIONS: The microshear bond strength of resin composite bonded to hypomineralized enamel was significantly lower than for control enamel. This was supported by differences seen in etch patterns and at the enamel-adhesive interface.     

自酸蚀粘接剂Adper Easy One的临床研究

目的评价一步法自酸蚀粘接剂Adper Easy One一年复诊期内的临床效果。方法临床选择有2颗恒磨牙面洞的患者27例,按随机数表选择其中一颗牙使用Adper Easy one自酸蚀粘接剂(自酸蚀组),另一颗牙使用Scotchbond酸蚀剂及Adper Single Bond2粘接剂(全酸蚀组),两颗牙均充填Filtek Z350树脂。术后即刻、1周、半年及1年复诊评价术后敏感,并按USPHS/Ryge标准评估充填体情况。结果自酸蚀组1例发生术后敏感,全酸蚀组2例发生术后敏感,两组差异无统计学意义(P>0.05)。全酸蚀组1例充填体边缘不完整,自酸蚀组所有病例充填体边缘完整,两组差异无统计学意义(P>0.05)。所有充填体颜色匹配、解剖学形态、表面质地均在1年复诊期内保持良好,未发生洞缘变色及继发龋。结论一步法自酸蚀粘接剂1年复诊期内术后敏感发生率低,临床效果保持良好。     

Microleakage in class V composite and compomer restorations following exposure to a colutory prescribed for the treatment of xerostomy

The purpose of this study was to evaluate the effect of a colutory (XeroLacer, Lacer), prescribed for the treatment of xerostomy, on microleakage into class V cavities filled with a composite (Z100, 3M ESPE) or a compomer (F2000, 3M ESPE) in combination with either a two-step etch-and-rinse adhesive (Adper Scotchbond 1XT, 3M ESPE) or a self-etching adhesive (Adper Prompt L-Pop, 3M ESPE). Class V cavities were made in the buccal surfaces of 80 bovine lower incisors which were randomly divided into four groups (n = 20): (1) Adper Scotchbond 1XT/Z100; (2) Adper Scotchbond 1XT/F2000; (3) Adper Prompt L-Pop/Z100; and (4) Adper PLP/F2000. All specimens were immersed in distilled water for 3 months and ten specimens of each group were immersed and vibrated in XeroLacer for 2 min three times a day. The specimens were dyed with 1% methylene blue for 24 h. Longitudinal sections were made and percentages of microleakage were determined by image analysis. In distilled water, microleakage with the Adper Scotchbond 1XT/F2000 combination was significantly greater than with Adper Scotchbond 1XT/Z100 or Adper Prompt L-Pop/Z100, and microleakage with Adper Prompt L-Pop/F2000 was significantly greater than that with Adper Prompt L-Pop/Z100. No significant differences were detected among the groups exposed to XeroLacer. However microleakage was significantly less with Adper Scotchbond 1XT/F2000 after exposure to XeroLacer than after immersion in distilled water only. In conclusion, exposure to XeroLacer decreased microleakage into cavities restored with the compomer.     

Effect of pulpal pressure on the microtensile bond strength of luting resin cements to human dentin

ObjectivesThe objectives of this study were to examine the effect of pulpal pressure on the microtensile bond strength (mTBS) of luting resin cements to human dentin and the permeability of dentin surfaces pre-treated with an adhesive and a self-etching primer.MethodsCylindrical composite blocks were luted with resin cements (RelyX ARC, 3M ESPE: ARC; Panavia F, Kuraray Medical Inc.: PF; RelyX Unicem, 3M ESPE: UN) in the absence or presence of simulated pulpal pressure. The application of Adper Single Bond 2 (3M ESPE) and ED primer 2.0 (Kuraray) was performed under 0 cm H₂O. After each resin cement was applied, the pulpal pressure group was subjected to 20 cm H₂O of hydrostatic pressure for 10 min during the initial setting period. Testing for mTBS was performed on 0.9 mm × 0.9 mm sectioned beams after 24 h water-storage. Scanning electron microscopy was performed to investigate the fractured surfaces after mTBS testing and additional dentin surfaces that were treated by an etchant, ED primer 2.0 and UN. Fluid permeability was measured on dentin surfaces that were applied with Adper Single Bond 2 and ED primer 2.0.ResultsApplication of pulpal pressure reduced mTBS significantly in groups ARC and PF. Porous bonding interfaces due to water permeability through the cured adhesive were observed on fractured surfaces. Dentin surfaces that were applied with the adhesive and the primer were more permeable than smear layer-covered dentin. The mTBS of UN was significantly lower than ARC and PF regardless of the absence/presence of pulpal pressure.SignificanceFluid permeation during the initial setting period deteriorated the bonding quality of resin cements.     

Microtensile bond strength of current dentin adhesives measured immediately and 24 hours after application

PURPOSE: To evaluate the immediate microtensile bond strengths achieved with representative adhesive systems from each of the four current bonding approaches. MATERIALS AND METHODS: Resin composite was bonded incrementally to flat, midcoronal dentin from 33 human molars, using the adhesives (Adper Scotchbond MP; Adper Scotchbond 1; Optibond Solo Plus; Clearfil SE Bond; AdheSE; Tyrian SPE + One Step Plus; Optibond Solo Plus self-etching; One-Up Bond F; iBond; Adper Prompt L-Pop; Xeno III) according to the respective manufacturer's instructions. The bonded specimens were immediately sectioned into sticks and underwent microtensile bond testing either immediately or after 24 h. Data were analyzed with two-way ANOVA and LSD tests. RESULTS: No significant differences were found between immediate and 24-h bond strengths (p > 0.05). However, significant differences were observed among adhesives (p = 0.001). The all-in-one adhesive iBond showed statistically lower values when compared to all the other adhesives. Adper Prompt L-Pop, Xeno III, Tyrian SPE + One Step Plus and One-Up Bond F, all self-etching adhesives, were significantly weaker than AdheSE, Optibond Solo Plus, Adper Scotchbond 1, Optibond Solo Plus self-etching, Clearfil SE Bond, and Adper Scotchbond MP, which did not differ statistically from each other. CONCLUSION: Microtensile bond strengths of representative adhesive systems from the four categories of bonding agents were not equivalent, with the lowest values recorded for the one-step self-etching adhesives. There were no differences in the bond strengths when measured immediately and after 24 h.