Fuad Jacob Abi Rached-Junior

Changes in the surface of four calcium silicate-containing endodontic materials and an epoxy resin-based sealer after a solubility test

AIMnTo compare the changes in the surface structure and elemental distribution, as well as the percentage of ion release, of four calcium silicate-containing endodontic materials with a well-established epoxy resin-based sealer, submitted to a solubility test.nnnMETHODOLOGYnSolubility of AH Plus, iRoot SP, MTA Fillapex, Sealapex and MTA-Angelus (MTA-A) was tested according to ANSI/ADA Specification 57. The deionized water used in the solubility test was submitted to atomic absorption spectrophotometry to determine and quantify Ca(2+), Na(+), K(+), Zn(2+), Ni(2+) and Pb(2+) ions release. In addition, the outer and inner surfaces of nonsubmitted and submitted samples of each material to the solubility test were analysed by means of scanning electron microscopy and energy-dispersive spectroscopy (SEM/EDX). Statistical analysis was performed by using one-way anova and Tukeys post hoc tests (α = 0.05).nnnRESULTSnSolubility results, in percentage, sorted in an increasing order were -1.24 ± 0.19 (MTA-A), 0.28 ± 0.08 (AH Plus), 5.65 ± 0.80 (Sealapex), 14.89 ± 0.73 (MTA Fillapex) and 20.64 ± 1.42 (iRoot SP). AH Plus and MTA-A were statistically similar (P > 0.05), but different from the other materials (P < 0.05). High levels of Ca(2+) ion release were observed in all groups except AH Plus sealer. MTA-A also had the highest release of Na(2+) and K(+) ions. Zn(+2) ion release was observed only with AH Plus and Sealapex sealers. After the solubility test, all surfaces had morphological changes. The loss of matrix was evident and the filler particles were more distinguishable. EDX analysis displayed high levels of calcium and carbon at the surface of Sealapex, MTA Fillapex and iRoot SP.nnnCONCLUSIONSnAH Plus and MTA-A were in accordance with ANSI/ADAs requirements regarding solubility whilst iRoot SP, MTA Fillapex and Sealapex did not fulfil ANSI/ADAs protocols. High levels of Ca(2+) ion release were observed in all materials except AH Plus. SEM/EDX analysis revealed that all samples had morphological changes in both outer and inner surfaces after the solubility test. High levels of calcium and carbon were also observed at the surface of all materials except AH Plus and MTA-A.

Evaluation of physicochemical properties of four root canal sealers.

AIMnTo assess the physicochemical properties and the surface morphology of AH Plus, GuttaFlow, RoekoSeal and Activ GP root canal sealers.nnnMETHODOLOGYnFive samples of each material were evaluated for setting time, dimensional alteration, solubility and radiopacity tests, according to ANSI/ADA Specification 57. A total of 50 mL of deionized distilled water from the solubility tests were used to measure the metal solubility by atomic absorption spectrometry. The morphologies of the external surface and the cross-section of the samples were analysed by means of a scanning electron microscope (SEM). Statistical analysis was performed by using one-way anova and post hoc Tukey-Kramer tests with the null hypothesis set as 5%.nnnRESULTSnAH Plus had the longest setting time (580.6 ± 3.05 min) (P<0.05). Activ GP did not have a mean value on the radiopacity and solubility tests (1.31 ± 0.35 mm and 11.8 ± 0.43%, respectively) in accordance with ANSI/ADA, being significantly different from the other materials (P<0.05), which had mean values for these tests in accordance with the ADAs requirements. GuttaFlow was the only sealer that conformed to the Specification 57 concerning the dimensional alteration test (0.44 ± 0.16%) (P<0.05). The spectrometry test revealed significant Ca(2+), K(+), Zn(2+) ion release from Activ GP sealer (32.57 ± 5.0, 1.57 ± 0.22 and 8.20 ± 1.74 μg mL(-1), respectively). In SEM analysis, the loss of matrix was evident and the filler particles were more distinguishable in all groups.nnnCONCLUSIONSnThe setting time of all sealers was in accordance with ANSI/ADAs requirements. Activ GP did not fulfill ANSI/ADAs protocols regarding radiopacity, dimensional alteration and solubility. GuttaFlow was the only sealer that conformed to the Specification 57 in all tests. SEM analysis revealed that the surfaces of all sealers had micromorphological changes after the solubility test.

Push-out strength of root fillings with or without thermomechanical compaction

AIMnTo evaluate the influence of thermomechanical compaction (Taggers hybrid technique - THT) on the push-out strength of several root filling materials to root dentine.nnnMETHODOLOGYnRoot canals of eighty roots in human canines were prepared with the ProTaper system and filled with one of the following materials, using either lateral compaction (LC) (n = 40) or THT (n = 40): AH Plus/gutta-percha (GP) (n = 10), Sealer 26/GP (n = 10), Epiphany SE/Resilon (n = 10) and Epiphany SE/GP (n = 10). Three 2-mm-thick dentine slices were obtained from each third of each root. The root filling in the first slice was subjected to a push-out test to evaluate the bond strength of the materials to intraradicular dentine. Data (in MPa) were analysed using anova and post hoc Tukeys test (P < 0.05). Failure mode was determined at × 25 magnification. The other two slices were prepared for scanning electron microscopy (SEM) to examine the surface of the filling materials.nnnRESULTSnLateral compaction (1.34 ± 1.14 MPa) was associated with a significantly higher bond strength (P < 0.05) than the THT (0.97 ± 0.88 MPa). AH Plus/GP (2.23 ± 0.83 MPa) and Sealer 26/GP (1.86 ± 0.50 MPa) had significantly higher bond strengths than the other materials and differed significantly from each other (P < 0.05). There was a significant difference (P < 0.05) between the coronal (1.36 ± 1.15 MPa), middle (1.14 ± 1.05 MPa) and apical thirds (0.95 ± 0.83 MPa). Considering the technique and root filling material interaction, AH Plus/GP-LC was associated with the highest mean values (2.65 ± 0.66 MPa) (P < 0.05). Sealer 26/GP-LC (2.10 ± 0.46 MPa), AH Plus/GP-THT (1.81 ± 0.78 MPa) and Sealer 26/GP-TH (1.63 ± 0.44 MPa) had intermediate values that were not significantly different from each other (P > 0.05). Epiphany SE was associated with the lowest mean values (3.70 ± 0.86 MPa) (P < 0.05), regardless of the root filling technique and type of solid material (cone). Adhesive failures predominated in the specimens filled with Epiphany SE, whilst mixed and cohesive failures were more frequent in those filled with AH Plus and Sealer 26, regardless of the root filling technique. SEM analysis revealed that LC produced a dense and well-compacted filling whilst the use of a hybrid thermomechanical technique resulted in the solid material (GP or Resilon) intermingled within sealer to form a nonhomogenous mass.nnnCONCLUSIONnLateral compaction was associated with higher bond strengths of the materials to intraradicular dentine than a hybrid technique using thermomechanical compaction. The greatest push-out strengths were obtained when the canals were filled with LC of AH Plus and GP cones.

Push‐out strength of methacrylate resin‐based sealers to root canal walls

AIMnTo assess the push-out strength of Epiphany SE, Epiphany and Hybrid Root SEAL to the dentine walls of root canals.nnnMETHODOLOGYnSixty roots of canines were prepared and distributed to six groups (n = 10) according to the filling material: GI - Epiphany SE, GII - Epiphany primer and sealer, GIII - Epiphany primer, sealer and resinous solvent, GIV - Clearfil DC Bond and Epiphany sealer, GV - Clearfil, Epiphany sealer and solvent and GVI - Hybrid Root SEAL. Resilon cones were used in all groups. Roots were sectioned transversally to obtain three slices from each third. One slice was subjected to the push-out test (MPa), and results were analysed by anova and Tukeys test (P < 0.05). The other two slices were prepared for scanning electron microscopy (SEM). Failure mode was also analysed.nnnRESULTSnA statistically significant difference (P <0.05) occurred between Hybrid Root SEAL (5.27 +/- 2.07) and the other materials, GI (0.40 +/- 0.23), GII (0.78 +/- 0.45), GIII (0.57 +/- 0.28), GIV (0.40 +/- 0.24) and GV (0.50 +/- 0.41), which did not differ significantly from each other (P > 0.05). Adhesive failures predominated in groups I, II, IV and V, whilst mixed and cohesive failures were the most frequent in groups III and VI, respectively. There were gaps in the adhesive interface of GI and GII, continuity areas of the filling material with dentine in GIV and GV and good adaptation of the interface of GVI.nnnCONCLUSIONnHybrid Root SEAL had greater push-out strength to root canal dentine than Epiphany SE and Epiphany. The use of primer, solvent and adhesive system did not influence the adhesion of Epiphany.

Physicochemical Properties of Methacrylate Resin–based Root Canal Sealers

INTRODUCTIONnThis study assessed in vitro the physicochemical properties of 2 methacrylate resin-based sealers (Epiphany SE and Hybrid Root SEAL), comparing the results with a well-established epoxy resin-based sealer (AH Plus).nnnMETHODSnFive samples of each material were used for each test (setting time, flow, radiopacity, dimensional change after setting, and solubility) according to American National Standards Institute/American Dental Association (ANSI/ADA) Specification 57. The samples were assigned to 3 groups: I, AH Plus; II, Epiphany SE; and III, Hybrid Root SEAL. The distilled and deionized water used at the solubility test was submitted to atomic absorption spectrometry to observe the presence of Ca2+, K+, Ni2+, and Zn2+ ions. In addition, the surface morphology of the specimens was analyzed by means of scanning electron microscopy (SEM). Statistical analysis was performed by using one-way analysis of variance and Tukey-Kramer test (P < .05).nnnRESULTSnFlow, radiopacity, and solubility of all sealers were in accordance with ANSI/ADA. The setting time of Hybrid Root SEAL did not agree with ANSI/ADA requirements. The dimensional change of all sealers was greater than the values considered acceptable by ANSI/ADA. The spectrometry analysis showed significant Ca(2+) ions release for AH Plus. In SEM analysis, Hybrid Root SEAL presented spherical monomers with inferior size than AH Plus and Epiphany SE.nnnCONCLUSIONSnIt might be concluded that physicochemical properties of the tested sealers conformed to ANSI/ADA (2000) standardization, except for the setting time of Hybrid Root SEAL and the dimensional change of all sealers, which did not fulfill the ANSI/ADA requirements.

Bond Strength of Epiphany Sealer Prepared with Resinous Solvent

This study evaluated in vitro the bond strength of Epiphany sealer prepared with resinous solvent of Epiphany system (Thinning resin) by using a push-out test. Forty maxillary canines were sectioned transversally below the cementoenamel junction to provide 4-mm-thick dentin disks that were centered in aluminum rings and embedded in acrylic resin. Root canals were prepared with tapered diamond bur. Intraradicular dentin was treated with 1% NaOCl for 30 minutes, 17% ethylenediaminetetraacetic acid for 5 minutes, and flushed with distilled water for 1 minute. The specimens were randomly distributed into 4 groups (n = 10) according to the filling material: GI, Epiphany without photoactivation; GII, Epiphany prepared with solvent without photoactivation; GIII, Epiphany followed by photoactivation; and GIV, Epiphany prepared with solvent followed by photoactivation. After the setting time, the specimens were submitted to the push-out test. The highest mean value (14.91 +/- 2.82 MPa) was obtained with Epiphany prepared with solvent followed by photoactivation (GIV), which was statistically different (P < .01) from the other groups. Groups I (8.15 +/- 2.47 MPa), II (9.46 +/- 2.38 MPa), and III (9.80 +/- 2.51 MPa) had inferior bond strength values and were statistically similar among themselves (P > .01). The resinous solvent of Epiphany system increased the bond strength of Epiphany sealer to dentin walls when followed by photoactivation.

Physicochemical properties of endodontic sealers of different bases

Objective To assess the setting time (ST), flow (FL), radiopacity (RD), solubility (SB) and dimensional change following setting (DC) of different sealers (AH Plus®, Polifil, Apexit Plus®, Sealapex®, Endométhasone® and Endofill® according to American National Standards Institute/American Dental Association (ANSI/ADA) Specification 57. Material and methods Five samples of each material were used for each test. For ST, cast rings were filled with sealers and tested with a Gilmore needle. For FL, the sealer was placed on a glass plate. After 180 s, another plate with 20 g and a load of 100 g were applied on the material, and the diameters of the discs formed were measured. In RD, circular molds were filled with the sealers, radiographed and analyzed using Digora software. For SB, circular molds were filled with the sealers, a nylon thread was placed inside the material and another glass plate was positioned on the set, pressed and stored at 37ºC. Samples were weighed, placed in water, dried and reweighed. The water used for SB was analyzed by atomic absorption spectrometry. For DC, circular molds were filled with the sealers, covered by glass plates and stored at 37ºC. Samples were measured and stored in water for 30 days. After this period, they were dryed and measured again. Results Regarding ST, AH Plus®, Apexit® and Endofil® sealers are in accordance with ANSI/ADA standards. Endométhasones manufacturer did not mention the ST; Polifil is an experimental sealer and Sealapex® did not set. Considering RD, SB and DC, all sealers were in accordance with ANSI/ADA. The spectrometric analysis showed that a significant amount of K+ and Zn2+ ions was released from Apexit Plus® and Endofill®, respectively. Conclusion Except for DC, all other physicochemical properties of the tested sealers conformed to ANSI/ADA requirements.

Impact of remaining zinc oxide-eugenol-based sealer on the bond strength of a resinous sealer to dentine after root canal retreatment.

AIMnTo evaluate the bond strength of a resin-based sealer (AH Plus) to root canal dentine after the removal of a zinc oxide-eugenol-based sealer (Endofill), using different retreatment techniques.nnnMETHODOLOGYnThe root canals of sixty-four maxillary incisors were prepared with ProTaper and filled with Endofill/gutta-percha. After thermocycling, the roots were randomly assigned according to the retreatment technique (n = 16): (A) ProTaper, (B) ProTaper/xylol, (C) ultrasound and (D) ultrasound/xylol and according to whether an operating microscope (OM) was used or not (n = 8): GI- direct vision (DV) and GII- indirect through the OM. Eight additional roots were instrumented and filled with AH Plus/gutta-percha (control). Roots were sectioned to obtain 1-mm-thick slices. Slices were used in the push-out test and in confocal microscopy. Data were submitted to anova and Tukey test (α = 0.05).nnnRESULTSnThe specimens filled under the OM (2.50 ± 0.90) had higher bond strength values of sealer to root canal walls (P < 0.05). The control group had superior mean adhesion values (4.75 ± 1.47) that were significantly different from the others (P < 0.05). Ultrasound/xylol (2.53 ± 1.00) was superior to ultrasound (2.23 ± 0.72) (P < 0.05), ProTaper (2.20 ± 0.69), ProTaper/Xylol (2.12 ± 0.65), which were similar (P > 0.05). Bond strength was different in all thirds (P < 0.05) and decreased in the following sequence: cervical (3.19 ± 1.18), middle (2.58 ± 1.21) and apical (1.87 ± 0.68). Confocal analysis revealed residues of Endofill in dentinal tubules when the removal protocol was carried out with ProTaper, but not from ultrasound combined with xylol.nnnCONCLUSIONSnThe OM was associated with higher bond strength values for filling material to root canals. The zinc oxide-eugenol-based sealer negatively affected the bond strength of AH Plus to root canal walls, regardless of the retreatment technique.

Influence of Drying Protocol with Isopropyl Alcohol on the Bond Strength of Resin-based Sealers to the Root Dentin

INTRODUCTIONnThis study compared the bond strength, interfacial ultrastructure, and tag penetration of resin-based sealers applied to smear-free radicular dentin using 70% isopropyl alcohol as the active final rinse.nnnMETHODSnEighty root canals were prepared and assigned to 2 groups (nxa0=xa040) according to the drying protocol: paper points or 70% isopropyl alcohol. Then, roots were divided into 4 subgroups (nxa0=xa010) with respect to the sealer and obturation material: AH Plus (Dentsply De Trey GmbH, Konstanz, Germany) and gutta-percha (AH/GP), Hybrid Root SEAL (Sun Medical, Tokyo, Japan) and gutta-percha (HR/GP), Epiphany SE (Pentron Clinical Technologies, Wallingford, CT) and gutta-percha (EP/GP), and Epiphany SE and Resilon (EP/RS). Roots were sectioned, and the push-out test was performed. Failure modes were examined under stereomicroscopy and sealer penetration into the dentinal tubules under scanning electron microscopy. Data were statistically analyzed by 2-way analysis of variance post hoc Tukey tests with a significant level of 5%.nnnRESULTSnOverall, canals dried with isopropyl alcohol showed significantly higher bond strength values (2.11xa0±xa01.74xa0MPa) than with paper points (1.81xa0±xa01.73xa0MPa) (Pxa0<xa0.05). The HR/GP group showed lower bond strength than the AH/GP group (Pxa0<xa0.05) but higher than the EP/GP and EP/RS groups (Pxa0<xa0.05). The most frequent type of failure was cohesive in the AH/GP and HR/GP groups and adhesive in the EP/GP and EP/RS groups. Scanning electron microscopic evaluation revealed better adaptation of the adhesive interface in the AH/GP and HR/GP groups in comparison with the EP/GP and EP/RS groups.nnnCONCLUSIONSnA final rinse with EDTA and 70% isopropyl alcohol improved the bond strength and penetration of the sealers into dentinal tubules of the root.

Flexural properties, morphology and bond strength of fiber-reinforced posts: influence of post pretreatment

The aim of this study was to assess the influence of surface pretreatments of fiber-reinforced posts on flexural strength (FS), modulus of elasticity (ME) and morphology of these posts, as well as the bond strength (BS) between posts and core material. Fifty-two fiber posts (smooth and serrated) were assigned to 4 groups (n=13): no treatment (control), 10% hydrogen peroxide (HP) for 10 min (HP-10), 24% HP for 1 min (HP-24) and airborne-particle abrasion (Al(2)O(3)). To evaluate FS and ME, a 3-point bending test was performed. Three posts of each group were examined by scanning electron microscopy. Composite resin was used as the core build-up and samples were sectioned to obtain microtensile sticks. Data were analyzed by ANOVA and Tukeys test (α=0.05). For FS, significant differences were observed between posts type and surface pretreatment (p<0.05), with the highest means for the smooth posts. Al2O3 provided higher FS than HP-24. Al(2)O(3) promoted higher ME than HP-24 and control. SEM images revealed partial dissolution of the resin matrix in all treated groups. The smooth posts had higher BS and FS than serrated posts (p<0.05). Mechanical properties of the glass fiber posts and the bond strength between posts and composite material were not altered by the surface treatments, except for airborne-particle abrasion that increased the post elastic modulus.