The Efficacy of Different Sealer Removal Protocols on Bonding of Self-etching Adhesives to AH Plus–contaminated Dentin

IntroductionSmearing of unset root canal sealers over the pulp chamber dentin may adversely affect bonding of self-etching adhesives and jeopardize their coronal sealing potential. This study examined the influence of different sealer removal protocols on the microtensile bond strengths of two self-etching adhesives to AH Plus-contaminated dentin.MethodsCoronal dentin surfaces were prepared from extracted human third molars. In the positive control groups, these surfaces were not contaminated with sealer and were bonded with Clearfil SE Bond or Clearfil Tri-S Bond. For the experimental groups, dentin surfaces were contaminated with AH Plus and wiped with either dry cotton pellets, cotton pellets saturated with ethanol, or cotton pellets saturated with Endosolv R followed by rinsing the dissolved sealer with water prior to bonding with the two adhesives. Bonded specimens were sectioned into resin-dentin beams for microtensile bond strength evaluation. Additional specimens were prepared for transmission electron microscopy to examine the ultrastructure and nanoleakage within the hybrid layers.ResultsFor both adhesives, microtensile bond strengths significantly declined when the sealer was removed with dry cotton pellets or cotton pellets saturated with ethanol. Only the Endosolv R/water sealer removal protocol restored tensile bond strengths to those of the uncontaminated positive controls without adversely affecting hybrid layer formation in intact dentin or increasing nanoleakage within the resin-dentin interfaces.ConclusionThe Endosolv R sealer removal protocol appears to be effective in preventing the deterioration of bond strengths of the two self-etching adhesives to AH Plus–contaminated dentin and warrants further clinical investigation.     

Effect of desensitizing agents on the microtensile bond strength of two‐step etch‐and‐rinse adhesives to dentin

Desensitizers can be used to control postoperative sensitivity in adhesive restorations. The aim of this study was to evaluate the effect of desensitizing agents on the bond strength of two‐step etch‐and‐rinse adhesive systems to dentin. Forty‐two human molars were sectioned to obtain 3‐mm‐thick dentin discs. The discs were divided into three groups (n = 14 in each) – no‐treatment control group (CT), and oxalic acid [BisBlock (BB)] and calcium phosphate [Desensibilize Nano‐P (NP)] desensitizers – before the application of two adhesive systems [Adper Single Bond Plus (SB) and One‐Step Plus (OSP)]. A nanoparticle composite resin was used to create a 3‐mm‐thick build‐up. The specimens were stored in distilled water for 24 h before a microtensile bond‐strength test was performed. The failure modes were determined using a stereomicroscope at 100 × magnification. Specimens were sectioned perpendicular to the interface for scanning electron microscopy analyses. The CT‐SB group exhibited the highest bond strength, differing significantly from BB‐SB and BB‐OSP groups. Mixed failures were prevalent for all groups. Scanning electron microscopy revealed a continuous hybrid layer and resin tags in all groups. Dentin bond strength of etch‐and‐rinse adhesive systems was reduced by an oxalic acid desensitizer but was not affected by a calcium phosphate‐containing desensitizer.     

Influence of surface wetness on bonding effectiveness of universal adhesives in etch‐and‐rinse mode

The purpose of this study was to evaluate whether surface wetness would influence the bonding effectiveness of universal adhesives in etch‐and‐rinse mode. All‐Bond Universal (AB), G‐Premio Bond (GP), Prime & Bond Active (PB), and Scotchbond Universal Adhesive (SU) were evaluated. Initial bond strengths and bond‐fatigue strengths of universal adhesives to both wet and dry enamel and dentin in etch‐and‐rinse mode were determined. Scanning electron microscopy observations of the adhesive interfaces were also conducted. The bond‐fatigue durability of universal adhesive to enamel in etch‐and‐rinse mode was influenced by the surface wetness, unlike that to dentin. The bond fatigue durability of AB and GP to dentin in etch‐and‐rinse mode was different depending on the surface wetness, unlike that of PB and SU. The thicknesses of the adhesive or hybrid layer of resin–dentin interfaces were not influenced by the surface wetness, but the length of resin tags in the wet group was longer than in the dry group. Some universal adhesives with the addition of specific components and optimization of water content can achieve stable bonds regardless of surface wetness, but the surface wetness of dentin is still a significant factor for universal adhesive bonding in etch‐and rinse mode, unlike that of enamel.     

Relationship between mechanical properties and bond durability of short fiber‐reinforced resin composite with universal adhesive

The purpose of this study was to determine the relationship between mechanical properties and bond durability of short fiber‐reinforced resin composite with universal adhesive. As controls, micro‐hybrid and nano‐hybrid resin composites were tested. The universal adhesives used were Scotchbond Universal, Adhese Universal, and G‐Premio Bond. The fracture toughness and flexural properties of resin composites, and shear bond strength and shear fatigue strength of universal adhesive with resin composite using both total‐etch and self‐etch modes were determined. In the results, short fiber‐reinforced resin composite showed significantly higher fracture toughness than did micro‐hybrid and nano‐hybrid resin composites. The flexural strength and modulus of short fiber‐reinforced and nano‐hybrid resin composites were significantly lower than were those of micro‐hybrid resin composites. Regardless of etching mode, the shear bond strength of universal adhesives with short fiber‐reinforced resin composite did not show any significant differences from micro‐hybrid and nano‐hybrid resin composites. The shear fatigue strength of universal adhesives with short fiber‐reinforced resin composite and micro‐hybrid resin composites were significantly higher than that of nano‐hybrid resin composites. The results of this study suggest that the mechanical properties of short fiber‐reinforced resin composite improve their bond durability with universal adhesive.     

Adhesion to Er:YAG laser and bur prepared root and crown dentine

Background: The purpose of this study was to evaluate the bond strengths between dentine and resin composite obtained after Er:YAG laser treatment of crown or root dentine used together with self‐etch and total‐etch adhesive systems. Methods: One etch‐and‐rinse adhesive (Single Bond, 3M, USA) and one self‐etch system (Clearfil SE Bond, Kuraray, Japan) were applied to root and crown dentine prepared with a regular bur in a turbine or with an Er:YAG laser. The shear bond strength was determined after thermocycling and statistically analysed using independent t‐tests. Results: Crown sites bonded using Clearfil SE Bond and Single Bond adhesives yielded bond strengths similar to that of root dentine sites (p > 0.05). Clearfil SE Bond was stronger in both the lased and non‐lased groups (p < 0.05). The lowest bond strength was obtained when Single Bond without acid etching was used on Er:YAG ablated dentine. When total‐etch adhesive was used, there were significant differences (p < 0.05) between the laser‐ablated and laser‐ablated/acid‐etched and bur‐cut/acid‐etched groups. Conclusions: Er:YAG laser irradiation of root and crown dentine conducted prior to the adhesive protocol adversely affected adhesion and decreased bond strength compared with traditional preparation.     

Evaluation of the effect of MTAD in comparison with EDTA when employed as the final rinse on the shear bond strength of three endodontic sealers to dentine

The purpose of the study was to evaluate the effect of MTAD in comparison with EDTA as a final rinse on the shear bond strength of Kerr, Apexit and AH plus. Dentine surfaces of 135 extracted human non-carious maxillary premolars were divided into three groups (n = 45). Groups I and II were conditioned with 1.3% NaOCl for 20 min, followed by a final rinse of 17% EDTA for 1 min and MTAD for 5 min respectively. Group III was treated with distilled water. Each group was further divided into three subgroups (n = 15). Subgroup 1: Kerr, Subgroup 2: Apexit and Subgroup 3: AH plus. Three-millimetre-long sections of polyethylene tubes were filled with freshly mixed sealer and placed on the dentine surfaces. The bonding between the sealer and dentine surface was evaluated using shear bond testing. The values were statistically evaluated using one way anova followed by Tukey's test. Significant difference was found among the bond strength of the sealers and irrigating regimes. AH plus showed superior bond strength among the tested sealers, when EDTA was employed as the final rinse (P < 0.05). MTAD as a final rinse affected the bond strength of AH plus and Apexit, which were significantly lower than the control group.     

Comparison between universal adhesives and two‐step self‐etch adhesives in terms of dentin bond fatigue durability in self‐etch mode

This aim of this study was to compare universal adhesives and two‐step self‐etch adhesives in terms of dentin bond fatigue durability in self‐etch mode. Three universal adhesives – Clearfil Universal, G‐Premio Bond, and Scotchbond Universal Adhesive – and three‐two‐step self‐etch adhesives – Clearfil SE Bond, Clearfil SE Bond 2, and OptiBond XTR – were used. The initial shear bond strength and shear fatigue strength of resin composite bonded to adhesive on dentin in self‐etch mode were determined. Scanning electron microscopy observations of fracture surfaces after bond strength tests were also made. The initial shear bond strength of universal adhesives was material dependent, unlike that of two‐step self‐etch adhesives. The shear fatigue strength of Scotchbond Universal Adhesive was not significantly different from that of two‐step self‐etch adhesives, unlike the other universal adhesives. The shear fatigue strength of universal adhesives differed depending on the type of adhesive, unlike those of two‐step self‐etch adhesives. The results of this study encourage the continued use of two‐step self‐etch adhesive over some universal adhesives but suggest that changes to the composition of universal adhesives may lead to a dentin bond fatigue durability similar to that of two‐step self‐etch adhesives.     

Influence of Phosphoric Acid Etching on Bond Strength for Calcium Silicate-Based Sealers

IntroductionThis study evaluated the microtensile bond strength of calcium silicate-based sealers and epoxy resin-based sealer, depending on the use of phosphoric acid (PA) etching before immediate resin restoration.MethodsExposed dentin surfaces of extracted human third molars were randomly assigned to 3 groups depending on sealer type (AH Plus [Dentsply DeTrey], CeraSeal [Meta Biomed Co.], and EndoSeal MTA [Maruchi]). Half of the samples were treated with PA for 30 seconds, and the other half were cleaned with water. Completely untreated specimens were used as controls. Self-etching adhesive (Clearfil SE Bond, Kuraray) was applied and composite resin (Tetric N-Ceram, Ivoclar Vivadent) was used to create build-ups. After 24 hours, the microtensile bond strength was measured (EZ Test, Shimadzu Co.). The failure mode was determined by light microscopy and scanning electron microscopy. One-way analysis of variance with the Bonferroni correction was used to analyze the data (P < .05).ResultsThe bond strength of the water-washed dentin surfaces in the calcium silicate-based sealer groups did not differ significantly from those of the control surfaces but the PA-pretreated surfaces exhibited relatively low-bond strength. The AH Plus-treated group had lower bond strength than the control group when no PA treatment was applied, but PA treatment restored the bond strength. The adhesive failure mode was most frequently found in the AH Plus group without PA etching.ConclusionsWhen a water-soluble calcium silicate-based sealer is used, sufficient bond strength can be obtained by washing with water alone, with no need for PA use.     

The effect of calcium silicate-based sealer on the push-out bond strength of fibre posts

Background: The aim of this study was to assess the effect of the iRoot SP root canal sealer on the push‐out bond strength of fibre posts cemented with self‐adhesive resin cement. Methods:  Forty‐eight extracted maxillary incisors were randomly divided into four groups according to the tested sealer (n = 12): group 1 – control (only gutta‐percha points, no sealer); group 2 – AH Plus Jet (resin‐based sealer); group 3 – Endofill (zinc oxide‐eugenol‐based sealer); and group 4 – iRoot SP (calcium silicate‐based sealer). All root canals were filled with gutta‐percha, and groups 2–4 additionally received one of the sealers. Fibre posts were cemented with the self‐adhesive resin cement Clearfil SA Cement. The specimens were sectioned in the coronal, middle and apical regions, producing three slices of 1 mm thickness. The push‐out test was performed. All data were submitted to ANOVA and Tukey tests (α = 0.05). Results:  No statistically significant differences were found between the control group, AH Plus Jet and iRoot SP (p > 0.05). The Endofill sealer showed significantly lower bond strength compared to the other sealers and the control group (p < 0.05). Conclusions:  The calcium silicate‐based sealer did not adversely affect the bond strength of the fibre posts cemented with self‐adhesive resin cement.     

Push-out bond strengths of the dentine-sealer interface with and without a main cone

AIM: To evaluate the push-out bond strength of the dentine-sealer interface with and without main cone for three resin sealers. METHODOLOGY: Thirty extracted maxillary premolar teeth with two separate canals were prepared using 0.04 taper Profile instruments to size 35-45. Teeth were divided into three groups for filling using AH Plus, EndoREZ or Resilon sealers. In each tooth, one canal was filled with a matching single-cone technique, and other was filled with sealer alone. A 1 mm slice of mid-root dentine was prepared for the push-out test. Failure modes after push-out were examined under microscopy and field emission-scanning electron microscopy. Data were analysed using two-way anova and paired t-tests, with significance set at P < 0.05. RESULTS: Overall, the epoxy resin-based sealer provided the highest push-out bond strengths. Push-out bond strengths were significantly higher (P < 0.001) when canals were filled with sealer alone than those filled with main cone and sealer (AH Plus 6.6 and 2.0 MPa, respectively; Resilon 3.4 and 0.4 MPa; EndoREZ 0.9 and 0.4 MPa). Sealers appeared to behave differently as thin films in association with a main cone, compared with bulk material. They failed in cohesive mode within the thin film, leaving a layer of sealer on the canal surface. Bulk sealer showed predominantly adhesive failure at the dentine-sealer interface, with a clean dentine wall and with resin tags either partially pulled out or sheared off at the interface. CONCLUSION: Push-out bond strengths of resin sealers were much lower when the sealer was present as a thin layer.     

Evaluation of the adhesion of fiber posts cemented using different adhesive approaches

The aim of this study was to investigate the adhesion of fiber posts cemented with luting agents that utilize three currently available adhesive approaches: etch‐and‐rinse, self‐etch, and self‐adhesive. Forty‐two intact single‐rooted human premolars were used in the study. Teeth were divided into six groups. In each group, a different resin cement with its adhesive system (if needed) and a fiber post were used. The groups were classified, according to the adhesive approach, into the following three categories. (i) Etch‐and‐rinse groups: Calibra resin cement/XPBond adhesive + self‐curing activator (SCA)/RadiX Fiber Post (Dentsply Caulk), FluoroCore 2 core build‐up material/XPBond + SCA/RadiX Fiber Post (Dentsply Caulk), and MultiCore Flow luting and core build‐up material/Excite DSC adhesive/FRC Postec Plus fiber post (Ivoclar Vivadent). (ii) Self‐etch group: Panavia F 2.0/ED primer (Kuraray)/RadiX Fiber Post (Dentsply Caulk). (iii) Self‐adhesive groups: experimental self‐adhesive cement/RadiX Fiber Post (Dentsply Caulk), and RelyX Unicem/RelyX Fiber Post (3M ESPE). The adhesion between the post and the root canal walls was assessed using the ‘thin‐slice’ push‐out test. In the test arrangement used, the self‐etching approach may offer less favourable adhesion to root canal dentin in comparison with etch‐and‐rinse and self‐adhesive approaches.     

Thin and thick layers of resin‐based sealer cement bonded to root dentine compared: Adhesive behaviour

This study aims to evaluate tensile and shear bond strengths of one epoxy (AH) and two methacrylate resin‐based sealers (EZ and RS) in thin and thick layers bonded to root dentine. An alignment device was prepared for accurate positioning of 20 root dentine cylinders in a predefined gap of 0.1 or 1 mm. Sealer was placed in the interface. Bond strength tests were conducted. Mode of failures and representative surfaces were evaluated. Data were analysed using anova and post‐hoc tests, with P < 0.05. The thick layer of sealer produced higher bond strength, except for the shear bond strength of EZ. Significant differences between thin and thick layers were found only in tensile bond strengths of AH and RS. Mixed type of failure was constantly found with all sealers. Bond strengths of thick layers of resin‐based sealers to root dentine tended to be higher than with thin layers.     

The effect of thermal cycling on the bovine dentine shear bond strength of current adhesive systems

The aim of this study was to evaluate the effect of thermal cycling on shear bond strength to bovine dentine of four current adhesive systems. Forty bovine incisors were ground flat with #600-grit silicon carbide paper to obtain superficial coronal dentine surfaces. Three one-bottle (etch and rinse) adhesive systems (Single Bond, Bond 1, One Step), and one self-etching primer adhesive system (Clearfil Liner Bond 2V) were evaluated. Dentine was conditioned and bonded with the adhesive systems tested according to the manufacturers' instructions. A cylindrical teflon mould (3 x 4 mm) was placed over the bonded area (to eliminate the bonded surface) and filled with composite resin. For each adhesive system the filling composite used was from the same manufacturer. Ten specimens were prepared for each material and all specimens were conditioned at 37 degrees C for 24 h. Five specimens of each material (half of the specimens) were thermocycled at 5000 cycles (at 5, 37, 55 and 37 degrees C) with a dwell time of 15 s and bonds were stressed in shear at a rate of 0.5 mm min(-1) until failure. Data were analysed by one-way anova and Student-Newman-Keuls rank test (alpha=0.05). Statistical analysis revealed that thermal cycling significantly (P < 0.05) reduced the bond strengths of all adhesive systems. Bond strengths prior to thermocycling were not significantly different (P > 0.05), except for One Step which revealed the lowest bond strength, and varied from 22.5 +/- 3.34 to 10.98 +/-0.87 MPa. After thermal cycling, the bond strengths ranged from 9.35 +/- 1.13 to 6.06 +/- 1.77 MPa. Failures after testing and prior to thermal cycle were most commonly adhesive failures between the bonding resin and dentine associated with partial cohesive failures in the adhesive resin (type 2). Adhesive failures between bonding resin and dentin (type 1) after thermocycling were most commonly seen.     

Bond strength of AH Plus and Epiphany sealers on root dentine irradiated with 980 nm diode laser

Aim  To evaluate the bond strength of AH Plus and Epiphany sealers to human root canal dentine irradiated with a 980 nm diode laser at different power and frequency parameters, using the push-out test.
Methodology  Sixty canine roots were sectioned below the cementoenamel junction to provide 4-mm-thick dentine discs that had their root canals prepared with a tapered bur and irrigated with sodium hypochlorite, ethylenediaminetetraacetic acid and distilled water. The specimens were assigned to five groups ( n  = 12): one control (no laser) and four experimental groups that were submitted to 980 nm diode laser irradiation at different power (1.5 and 3.0 W) and frequency (continuous wave and 100 Hz) parameters. Half of specimens in each group had their canals filled with AH Plus sealer and half with Epiphany. The push-out test was performed and data (MPa) were analysed statistically by anova and Tukey's test ( P  < 0.05). The specimens were split longitudinally and examined under SEM to assess the failure modes after sealer displacement.
Results  The specimens irradiated with the diode laser and filled with AH Plus had significantly higher bond strength values (8.69 ± 2.44) than those irradiated and filled with Epiphany (3.28 ± 1.58) and the nonirradiated controls (3.86 ± 0.60). The specimens filled with Epiphany did not differ significantly to each other or to the control (1.75 ± 0.69). There was a predominance of adhesive failures at Epiphany–dentine interface (77%) and mixed failures at AH Plus–dentine interface (67%).
Conclusions  The 980 nm diode laser irradiation of root canal dentine increased the bond strength of AH Plus sealer, but did not affect the adhesion of Epiphany sealer.     

Effect of final irrigation protocols on push‐out bond strength of an epoxy resin root canal sealer to dentin

The purpose of the present study was to evaluate the effect of different final irrigation protocols on push‐out bond strength of an epoxy resin root canal sealer to dentin. Eighty single‐rooted anterior teeth were used. The root canals were partially prepared using a rotary system and the final diameter was standardised using a #5 Gates‐Glidden drill prior to the push‐out bond test. During chemomechanical preparation, 5.25% NaOCl or 2% CHX gel was used. For smear layer removal, 17% ethylenediaminetetraacetic acid (EDTA) or QMix 2 in 1 was applied for 3 min. As final irrigant, 1 mL of NaOCl, CHX solution or distilled water was used. On conclusion of preparation, canals were filled with gutta‐percha/AH Plus sealer. Bond strength was measured by the push‐out test. Data were statistically analysed by Kruskal–Wallis and Mann–Whitney U‐tests. The group NaOCl/EDTA/NaOCl showed significantly higher bond strength values than other groups. In all groups, there were mainly mixed failure patterns. It can be concluded that 5.25% NaOCl proved to be the best solution for the final irrigation when combined with EDTA. The final irrigation protocols affect the push‐out bond strength of AH Plus to dentin.     

The effects of dentine pretreatment on the adhesion of root-canal sealers

AIM: The adhesion of five root-canal sealers to dentine and gutta-percha was studied. The effects of various dentine pretreatments on adhesion were also investigated. METHODOLOGY: Root dentine cylinders, 4 mm in diameter, were prepared from human teeth. The dentine surfaces were conditioned with either 37% H(3)PO(4) for 30 s, 25% citric acid for 30 s, 17% EDTA for 5 min or a rinse with 10 mL distilled water (control). Gutta-percha cylinders, 4 mm in diameter, were prepared and their end surfaces polished flat. The dentine and gutta-percha surfaces were coated with freshly mixed sealer: Grossman's sealer (GS), Apexit (AP), Ketac-Endo (KE), AH Plus (AH), RoekoSeal Automix (RS) or RoekoSeal Automix with an experimental primer (RP). The surfaces were pressed together and the sealers allowed to set. The test specimens were subjected to a tensile force in a universal testing machine. RESULTS: Mean tensile bond strengths (MPa +/- SD) ranged from 0.07 +/- 0.01 (AP) to 1.19 +/- 0.47 (AH). Pretreatment with EDTA showed no effect or produced weaker bonds than controls. Phosphoric and citric acid pretreatments increased adhesion of GS. A primer used with RoekoSeal significantly enhanced its adhesion to untreated dentine. Inspection of fractured surfaces indicated failure of adhesion to dentine for GS and RS and to gutta-percha for KE and RP. The failure appeared to be mainly cohesive within the sealer for AH and AP. CONCLUSIONS: Removal of the smear layer may impair sealer adhesion to dentine. Different sealer types require different dentine pretreatments for optimal adhesion.     

Push‐out bond strength of gutta‐percha with a new bioceramic sealer in the presence or absence of smear layer

The purpose of this study was to compare the bond strength of a new bioceramic sealer (EndoSequence BC Sealer) and AH Plus in the presence or absence of smear layer. Extracted single‐rooted human teeth were prepared and randomly divided into four groups. In groups 1 and 3, the root canals were finally irrigated with 5.25% NaOCl and smear layer was not removed, but in groups 2 and 4, the root canals were finally irrigated with 17% EDTA followed by 5.25% NaOCl in order to remove the smear layer. In groups 1 and 2, the root canals were obturated with gutta‐percha/AH Plus, but in groups 3 and 4, obturation was performed with gutta‐percha/EndoSequence BC Sealer. Push‐out bond strength and failure modes were evaluated. The bond strength of gutta‐percha/AH Plus and gutta‐percha/EndoSequence BC Sealer was not significantly different (P = 0.89). The presence or absence of smear layer did not significantly affect the bond strength of filling materials (P = 0.69). The mode of bond failure was mainly cohesive for all groups. In conclusion, the bond strength of the new bioceramic sealer was equal to that of AH Plus with or without the smear layer.     

Effects of increased exposure times of simplified etch‐and‐rinse adhesives on the degradation of resin–dentin bonds and quality of the polymer network

Reis A, Ferreira SQ, Costa TRF, Klein‐Júnior CA, Meier MM, Loguercio AD. Effects of increased exposure times of simplified etch‐and‐rinse adhesives on the degradation of resin–dentin bonds and quality of the polymer network.
Eur J Oral Sci 2010; 118: 502–509. © 2010 Eur J Oral Sci One of the reasons for resin–dentin degradation is poor polymerization of the adhesive layer. This study evaluated the effect of prolonged polymerization times on the immediate and 6‐month resin–dentin bond strengths, silver nitrate uptake, and polymer quality of etch‐and‐rinse adhesives. Thirty extracted teeth were obtained, and a flat dentin surface was exposed on each tooth. Adhesives (Adper Single Bond 2 and One Step Plus) were applied to the dentin surface of these teeth and light‐cured for 10, 20, or 40 s at 600 mW cm^?2. Bonded sticks (0.6 mm²) were tested in tension (0.5 mm min^?1) and analyzed, after immersion in 50% silver nitrate, using scanning electron microscopy. The polymer quality of adhesive films was evaluated using thermogravimetric analysis. Statistically higher bond strengths were observed for both adhesives when light‐cured for 40 s. Degradation of dentin bonds occurred under all experimental conditions but it was less pronounced for adhesives light‐cured for 40 s. Longer exposure times reduced silver nitrate uptake for Adper Single Bond 2. Solvent retention and the amount of residual monomer were statistically lower when both adhesives were light‐cured for 40 s. Although longer exposure times than those recommended cannot prevent degradation of the dentin bonds, they can increase bond strength, probably because of the removal of an increased amount of solvent and the presence of a lower amount of residual monomer.     

Bond strength to radicular dentin and sealing ability of AH Plus in combination with a bonding agent

Abstract

Objective. To evaluate the sealing ability and bond strength of AH Plus sealer associated with the hybridization protocol of radicular dentin with Scotchbond Multi Purpose (SB). Materials and methods. Ninety palatal roots of maxillary molars were selected and divided into three groups (n = 30) according to filling protocol (G1, AH Plus/Resilon; G2, SB/AH Plus/Resilon; and G3, AH Plus/Gutta-Percha). In groups in which AH Plus + resin cones were used, dentin was hybridized before applying sealing material. For the bond strength test, 60 roots of bovine teeth were selected. Six holes were made in each root, two in the cervical, middle and apical third of the root. The roles were filled with AH Plus sealer with or without an adhesive system and submitted to push out test and the fracture mode was examined using a stereomicroscope (×32). Results. Statistical analysis showed that ScotchBond Multi Purpose (SB) + Resilon cone + AH Plus group promoted higher sealing ability than the gutta-percha + AH Plus group (p < 0.05). Bond strength was lower with SB application than without it (p < 0.05). A reverse correlation was found between bond strength and sealing ability. The fracture mode methodology revealed 22.77% of adhesive, 11.67% of cohesive and 65.55% of mixture fractures for SBMP/AH Plus protocol, whereas the AH Plus protocol indicated 86.11% of cohesive and 13.89% of mixed fractures. Conclusion. It was concluded that the use of the adhesive system Scotchbond Multi Purpose improved coronal sealing ability of AH Plus, but bond strength of sealer was reduced when adhesive was applied.     

Shear Bond Strengths of One-Bottle Adhesives to Oil-Contaminated Enamel

Purpose: To evaluate resin bond strength to enamel contaminated with handpiece oil. Materials and Methods: Bovine teeth were randomly assigned to six groups of 20 teeth each for treatment with one of six different bonding systems (five one‐bottle and one multibottle). For each system, 10 enamel specimens were contaminated with handpiece oil before acid‐etching and 10 were contaminated after acid‐etching. The enamel was etched for 15 seconds using 35% phosphoric acid. Following adhesive application, composite resin was bonded using a gelatin capsule technique. Shear bond strengths from the two contaminated groups were compared to bond strengths to uncontaminated enamel obtained from a previous study that was performed by the same group of investigators, using the same facility, materials, and methods. Results: Two‐way analysis of variance (ANOVA) showed that the factor “surface contamination” did not have a significant effect on bond strength (p > .542). The type of adhesive and the interaction of adhesive and surface contamination were significant (p <.0001 and p <.003, respectively). When oil was applied before etching, mean bond strengths ranged from 18.0 ± 4.8 MPa for OptiBond SOLO (Kerr Corp., Orange, California) to 25.3 ± 5.6 MPa for Tenure Quik with Fluoride (Den‐Mat Corp., Santa Maria, California). With oil applied after etching, bond strengths ranged from 18.4 ± 8.0 MPa for Tenure Quik with Fluoride to 27.4 ± 5.4 MPa for Single Bond (3M Dental Products, St. Paul, Minnesota). For the same adhesive, comparing uncontaminated and “oil‐before‐etch” contaminated groups, the only statistically significant difference in bond strengths was for OptiBond SOLO: 21.8 ± 4.0 MPa (uncontaminated) versus 18.0 ± 4.8 MPa (oil before etch). Comparing uncontaminated and “oil‐after‐etch” groups, the only statistically significant difference was for Tenure: 24.5 ± 5.7 MPa (uncontaminated) and 18.4 ± 8.0 MPa (oil after etch). CLINICAL SIGNIFICANCE Surface contamination with handpiece lubricant oil does not impair appreciably the efficacy of the adhesives used in this study when bonding composite resin to enamel.