Higher Push-out Bond Strength Research Articles

Influence of Er,Cr:YSGG Laser Irradiation on the Push-Out Bond Strength of Zirconia and Glass Fiber Posts with Radicular Dentin.

Objective This in vitro study was designed to evaluate the influence of an Er,Cr:YSGG laser on the bond strength of zirconia and glass fiber posts with root dentin. Materials and methods Ninety extracted single-rooted human teeth were randomized into 6 groups (n = 15/group) on the basis of different posts (zirconia/glass fiber) and Er,Cr:YSGG laser tips (axial and radial). Specimens were prepared for push-out testing with the help of a cutting machine; six slices (2 on each cervical, middle, and apical) of approximately 1 mm thickness were sectioned for all roots on a plane perpendicular to the long axis of the post. All specimens were placed into a universal testing machine with a defined 0.5 mm/min crosshead speed until the maximum failure load was obtained. Results The highest mean push-out bond strength of the glass fiber and zirconia groups was achieved with laser treatment. The highest push-out bond strength was achieved with the axial fiber tip (7.63 ± 1.22 MPa), and the lowest was achieved with a radial fiber tip of the glass fiber group (6.98 ± 0.96 MPa). ANOVA showed a statistically significant difference between the groups (p = 0.041). The mean push-out bond strength was found to be higher with an axial fiber tip for both cervical and apical segments in the glass fiber and zirconia groups (p < 0.05). The independent t-test resulted in the overall highest mean push-out bond strength in the apical segments (p = 0.026). Conclusion Within the limits of the present in vitro research study, an enhancement in the push-out bond strength of resin cement, mainly in the cervical region of the root canal, was achieved after irradiation with an Er,Cr:YSGG laser using an axial fiber tip.

Push-out bond strength of calcium-silicate cements following Er:YAG and diode laser irradiation of root dentin.

This study aimed to compare the effects of diode and Er:YAG laser irradiation of root dentin on push-out bond strength of mineral trioxide aggregate (MTA) and calcium-enriched mixture (CEM) cements. An in vitro experimental study was conducted on 90 dentin discs, cut out of freshly extracted human teeth. The discs were instrumented to obtain 1.3-mm lumen diameter. Then, they were randomly divided into six groups (n = 15). Groups 1 and 4 subjected to diode laser (Wiser, Doctor Smile, Italy) (980nm, 1W, continuous mode) for 10s and filled with MTA and CEM cements. Groups 2 and 5 subjected to Er:YAG laser (Deka, Italy) (2940nm, 1W, 10Hz, 230μs) for 10s and filled with MTA and CEM cements. Groups 3 and 6 (control groups) were filled with MTA and CEM cements without laser irradiation. After 7days, push-out bond strength test was performed using a universal testing machine in order to evaluate the adhesion of the biomaterials to dentin. The samples were evaluated under a light microscope at × 40 magnification to determine the mode of fracture. Data were analyzed using two-way ANOVA. The highest push-out bond strength (8.76 ± 3.62MPa) was noted in group 1 (diode/MTA), which was significantly higher than the other groups (P < 0.001). The lowest bond strength (2.61 ± 0.81) was noted in group 6 (control/CEM). Diode laser significantly increased the bond strength of both cements (P < 0.05), but Er:YAG laser irradiation only increased the bond strength of CEM and had no significant effect on MTA (P = 0.603). The bond strength of MTA control group was higher than that of CEM control group (P = 0.001). Push-out bond strength of endodontic cements can be affected by dentin conditioning with diode 980nm and Er:YAG laser. Nine hundred eighty-nanometer diode laser irradiation is recommended to increase the bond strength of endodontic cements particularly the CEM cement to dentin.

Effect of different irrigation solutions and techniques on push-out bond strength of resin-based sealer

Aim To evaluate the effect of irrigation solutions [sodium hypochlorite (NaOCl), chlorhexidine (CHX), and normal physiological saline] and different irrigation techniques (conventional needle, EndoVac, and CanalBrush) on push-out bond strength of AH Plus resin-based sealer. Materials and methods Ninety mandibular freshly extracted premolars were selected and divided into three groups according to the irrigation solutions; group I: 5.25% NaOCl, group II: 2% CHX, group III: normal physiological saline solution. Then each group was subdivided into three subgroups according to the irrigation techniques; subgroup A: 27 G side beveled needle, subgroup B: EndoVac irrigating system, subgroup C: medium-sized CanalBrush (30/0.04). Root canals of all groups were prepared using ProTaper Universal Ni-Ti rotary system up to file F4 (40/0.06) and filled by single cone technique using AH Plus sealer. 2 mm thick horizontal sections from the coronal, middle and apical thirds of each root were sliced for the push-out bond strength measurement and tested using universal testing machine. Data were analyzed using one-way analysis of variance in a level of significance (P ≤ 0.05). Results The highest mean push-out bond strength values were recorded for EndoVac system followed by CanalBrush and Needle in all groups and at all root canal levels. In comparison of irrigation solutions in needle subgroup; the highest values were recorded for CHX and least for NaOCl at coronal and middle root levels. While in the apical section, the highest and least mean push-out bond strength values were recorded for CHX and saline respectively. Regarding EndoVac and CanalBrush; the highest push-out bond strength values were recorded for CHX followed by saline and NaOCl at all root canal levels. Conclusions Whenever root canal obturation using AH Plus sealer, it is preferred to use 2% CHX solution throughout and after instrumentation via EndoVac system for improved bond strength. The coronal sections showed higher bond strength than middle and apical sections.

Comparative evaluation of the effect of various endodontic irrigants on the push-out bond strength of endosequence, Biodentine™, and MTA Plus™ root repair materials: An in vitro study

Aim: This study aimed to evaluate and compare the effects of 2% chlorhexidine and 3% sodium hypochlorite (NaOCl) irrigating solutions on the push-out bond strength of EndoSequence, Biodentine™, and MTA Plus™ root repair materials. Materials and Methods: Teeth were decoronated, and the midroot was sectioned horizontally into slices with the thickness of 2.0 mm with the help of diamond discs. The canal space was enlarged to diameter of 1.4 mm with the help of Gates-Glidden Drill. The samples were divided into three groups (n = 12). EndoSequence, Biodentine™, and MTA Plus™ root repair materials were condensed in the canal space and allowed to set for 10 min. The three groups were further subdivided into two subgroups each. Each material was immersed in NaOCl and chlorhexidine gluconate (CHX), respectively, for 30 min, rinsed with distilled water, and allowed to set for 48 h at 37°C with 100% humidity in an incubator. The push-out bond strength value was then measured using a universal testing machine. Data obtained were statistically analyzed. Results: EndoSequence root repair material (ERRM) proved to have the highest push-out bond strength followed by Biodentine™ and MTA Plus™ root repair materials. In subgroups, CHX in contact with ERRM showed the highest push-out bond strength followed by NaOCl, whereas Biodentine™ when in contact with NaOCl showed more push-out bond strength than when in contact with CHX. MTA Plus™ in contact with CHX showed the least push-out bond strength. Conclusion: The push-out bond strength of ERRM significantly increased after exposure to NaOCl and has the highest push-out bond strength followed by Biodentine™, and MTA Plus™ has the least push-out bond strength.

Comparative evaluation of push-out bond strength of gutta-percha using different sealers with lateral condensation and thermoplasticized obturation technique: An in vitro study.

Aim:The study aimed to evaluate and compare the push-out bond strength of gutta-percha using AH plus, Endosequence BC, and Roeko seal sealer with lateral condensation and thermoplasticized obturation technique.Materials and Methods:Sixty single-rooted premolars were instrumented and samples were randomly assigned into three groups based on the sealer used (Group A-AH Plus, Group B-Endosequence BC, Group C-Roeko Seal) which were further divided into two subgroups-A1, B1, and C1 were obturated by the lateral condensation technique and A2, B2, and C2 using the thermoplasticized technique. Each sample was sectioned horizontally using a diamond disc, representing apical, middle, and coronal thirds, respectively. Root segments were then mounted on an acrylic block, and push-out bond strength of each sample was tested using the universal testing machine.Statistical Analysis:One-way ANOVA, Tukey's test, and unpaired t-test.Results:For mandibular premolar teeth with a single canal using lateral condensation technique, the highest push-out bond strength was found in the A1 group (7.30 ± 0.61 MPa) at the apical level. While using the thermoplasticized technique, the highest push-out bond strength was found in the B2 group (3.71 ± 0.81 MPa) at the apical level. Overall results showed that the lateral condensation technique showed significantly higher push-out bond strength than thermoplasticized technique (P < 0.028).Conclusions:The push-out bond strength of AH Plus sealer was higher than the Endosequence BC sealer and Roeko seal sealer. Lateral condensation technique has shown higher push-out bond strength than the thermoplasticized technique.

Evaluation of the effect of endodontic chelating solutions on push out bond strength of endodontic sealers (An in-vitro study)

Aim: This study was carried out to evaluate the effect of various chelating solutions (EDTA-Apple Vinegar-Sodium Hypochlorite)on the radicular push-out bond strength of zinc oxide nanosealer and AH Plus resin based rootcanal sealer. Materials and Methods: 180 extracted single-rooted human teeth with complete roots, fully formed apices were used in this study,on completion of instrumentation, the specimens will be randomly divided into three groups (n=60) according to chelating solution applied: Group ( I ) 1.5 mL of 17% EDTA (pH = 7), Group ( II ) 2.5 mL of vinegar apple and Group ( III ) 2 mL of 5.25% sodium hypochlorite (NaOCl). These groups are subdivided into two subgroups (n=30) each according to root canal sealer used: Subgroup A: AH Plus and Subgroup B: Zinc oxide nanosealer. Then the specimens in the subgroups will be further randomly divided into two groups (n=15) according to storage time: Subgroup 1:one week storage time and Subgroup 2: one month storage time The root canals were prepared using ProTaper rotary instruments up to master apical rotary size F3 (#30), in conjunction with 2 mL of Normal saline solution (Sodium Chloride 0.9%) irrigation between each file and the chelating solution was applied for 1 minute then final rinse with distilled water. The sealers were loaded and introduced to the canal using K file size40.Testing push-out bond strength was done for all samples using the Intrson universal testing machine. Results: It was found that the highest push-out bond strength mean value recorded for (EDTA+ AH Plus) (1 week) group (IA1) (3.424 MPa) followed by (Apple Vinegar+ AH Plus) (1 week) group (IIA1) (1.263 MPa) while the lowest mean value recorded for (NaOCl+ZnO nanosealer) (1 month) group (IIIb2) (0.575 MPa). The difference between different groups was statistically significant as revealed with one way ANOVA test (p 0.05) differences between {(Apple Vinegar+AH Plus) and (NaOCl +AH Plus) (1 week)}, {( EDTA+ AH Plus), (Apple Vinegar+ AH Plus) and(NaOCl+ AH Plus) (1 month)}, {(EDTA+ ZnO nanosealer) and (NaOCl+ ZnO nanosealer) (1 month)}. Conclusions: AH Plus sealer had the highest push-out bond strength when used with EDTA, ZnO nanosealer had the highest push –out when used with apple vinegar and all AH Plus subgroups had higher push-out bond strength than ZnO nanosealers subgroups

The effects of chelation on the adhesion of two different root canal sealers

Objective: This study aims to evaluate alterations in the root canal dentin after irrigation with EDTA, HEBP, and Chitosan in order to determine the push-out bond strengths of the different root canal sealers on altered dentin surfaces. Materials And Methods: Crowns of 70 maxillary single-rooted teeth were removed to obtain a standardized length of 16 mm. The canals were instrumented using rotary files and the step back technique. The master apical file used in this study was #40. The subgroups were determined based on the chelation agent and the material of the root canal sealer that was used (17% EDTA, 18% HEPB, 0.2% Chitosan, Well Root ST (WRST) or AH Plus). Three slices with 1 mm thickness were cut from the root thirds of each tooth and subjected to a push-out test. The data (MPa) were analyzed using a one-way ANOVA and a Duncan’s multiple comparison test at a level of α = 0.05. Finally, scanning electron microscope (SEM) photographs were taken. Results: Groups that used WRST exhibited significantly higher push-out bond strength values in all subgroups independent of the irrigant that was used (ANOVA, p < 0.05). Group 1 showed higher push-out bond strength than the other AH Plus subgroups. Conclusion: The EDTA improved the push-out bond strength of the AH Plus. The WRST root canal sealer had the highest push-out bond strength and did not depend on the irrigant used.

Effect of ultrasonic and sonic activation of root canal sealers on the push-out bond strength and interfacial adaptation to root canal dentine.

To evaluate the effect of ultrasonic and sonic activation of two root canal sealers on interfacial adaptation and push-out bond strength (BS) to root canal dentine. The root canals of seventy-eight roots of maxillary canines were prepared with NiTi rotary instruments under irrigation with 2.5% NaOCl and 17% EDTA. Canals were filled by lateral condensation of gutta-percha and AH Plus (n=39) or MTA Fillapex (n=39). Three subgroups (n=13) were formed according to sealer activation: no activation (NA), sonic activation (SA, 20s) and ultrasonic activation (US, 20s). In three specimens of each subgroup, 0.1% rhodamine B was added to the sealer. Three 1-mm-thick slices were obtained from each root third. The first and second were used for push-out BS test and the third for a qualitative analysis of interfacial adaptation (gaps) and voids by confocal laser scanning microscopy (CLSM). Intratubular penetration of rhodamine B-labelled sealer was also assessed by CLSM. Data were analysed by two-way anova and Tukey's test (α=0.05). AH Plus (2.58±1.21) had higher push-out BS than MTA Fillapex (1.45±0.71) (P= 0.000). UA (2.64±1.44) had higher BS (P=0.000) than NA (1.58±0.73) and SA (1.83±0.85), which did not differ significantly from each other (P= 0.3303). The coronal third had higher BS (2.48± 1.49) than the middle (2.08±0.94) (P=0.0003) and apical (1.48±0.58) (P=0.00) thirds. For both sealers, UA was associated with a more homogeneous filling material with better interfacial adaptation and greater quantity, density and length of tags in dentinal tubules. When UA was used, the tags had similar quantity, density and length to those formed without activation, but interfacial gaps and voids were observed. Ultrasonic activation was associated with higher BS values, deeper intratubular penetration and greater interfacial adaptation to root dentine than sonic activation and no activation techniques, AH Plus had higher BS values than MTA Fillapex irrespective of the type of activation.

Influence of adhesive cementation systems on the bond strength of relined fiber posts to root dentin

Statement of problemGlass fiber post cementation procedures have undergone significant development. Relining the post with composite resin is a technique that aims to reduce resin cement thickness and consequently problems inherent to polymerization. Evidence is sparse regarding the efficacy of bonding procedures at increasing depths (from cervical to apical) using different adhesive cementation techniques. PurposeThe purpose of this in vitro study was to evaluate the push-out bond strength (PBS) of composite resin relined glass fiber posts cemented to bovine root dentin using different adhesive cementation protocols. Material and methodsEighteen bovine teeth (n=6) were embedded in polystyrene resin blocks, and the crowns were sectioned leaving a root portion of 20 mm in length. Root canals were prepared using rotary instruments provided by the post manufacturer (Whitepost DC #1), resulting in a uniform root canal preparation. The root canals were lubricated with a water-soluble glycerin gel. Silane (Prosil) was applied and the posts relined with a microhybrid composite resin (Filtek Z100) to conform to the root canal anatomy. Three adhesive cementation protocols were evaluated: a 3-step etch-and-rinse adhesive system (Adper Scotchbond Multi Purpose) in combination with a dual polymerizing resin cement (RelyX ARC); a universal adhesive system (Scotchbond Universal) associated with a dual polymerizing resin cement (RelyX Ultimate); and a self-adhesive dual polymerizing resin cement (RelyX Unicem 2). The roots were sectioned, resulting in four 2-mm segments at 4 different depths (cervical to apical) and evaluated by the PBS test, using a universal testing machine (Instron 4411) at 0.5 mm/min, until failure. Interfaces were evaluated by scanning electron microscopy, and failures were classified as cohesive failure in composite resin, cohesive failure in cement, cohesive failure in root dentin, adhesive failure, or mixed. Data were analyzed by 2-way split-plot ANOVA and the Tukey post hoc test (α=.05). ResultsNo statistical differences were found for PBS when different cementation systems were compared (P=.253). Increased depths resulted in reduced PBS values for all cementation protocols evaluated (P<.001). ConclusionsRegardless the cementation system used, the lowest PBS values were at the apical region of resin relined glass fiber posts bonded to root dentin. Furthermore, the highest PBS is observed at the cervical portion of root dentin.

Effect of antibacterial/adhesive approaches on bonding durability of fiber posts cemented with self-etch resin cement.

BackgroundLongevity of post-retained restoration is highly depended on bonding stability of fiber post (FP) to root dentin. This study evaluated the effect of different antibacterial/adhesive approaches on bonding durability of FPs luted into root canal with a self-etch cement.Material and MethodsSeventy-two human maxillary central incisor roots were divided into six groups after endodontic treatment, based on the antibacterial/adhesive treatments as follows: 1)ED primer II (ED, control); 2) Clearfil Protect Bond (PB); 3) 2% chlorhexidine (CH) pretreatment + ED primer II (CH+ED); 4) CH-incorporated into ED primer II (CH in ED); 5) CH pretreatment + Clearfil SE Bond (CH+SE); and 6)CH-incorporated into SE primer (CH in SE). The FPs were then cemented using PanaviaF2.0. After micro-slicing the bonded root dentin, a push-out bond strength (PBS) test was performed immediately or after two years of water storage. Data were analyzed using ANOVA and post hoc Tukey tests (α=0.05).ResultsThe effects of antibacterial/adhesive approach, time and interaction between the main factors were significant (p=0.01). There was no significant difference between the immediate groups, except between the CH+ED group (the lowest PBS) and PB and CH in SE groups (the highest PBS) (p≤0.03). After aging, the same difference was observed (p≤0.02); the control group exhibited a significantly lower PBS compared to the other groups (p≤0.01), except for CH+ED. Aging significantly decreased PBS of all the groups (p≤0.01); the control group exhibited the highest reduction.ConclusionsCH incorporated into self-etch primers or in pretreatment step prior to two-step self-etch adhesive and antibacterial adhesive could improve bond stability of self-etch cemented fiber post. However, none of these was capable of inhibiting bond degradation over time. Key words:Push-out bond strength, Fiber post, Chlorhexidine.

Effects of Silane on the Push-out Bond Strength of Fiber-reinforced Resin Posts luted with different Self-adhesive Resin Cements

ABSTRACT Aim The present study was completed to evaluate the effect of silane on the push-out bond strength on fiber-reinforced posts. The intention of the study was also to determine if there was a regional relation between the adhesive system and the push-out bond strength of the fiber post. Materials and methods Fifteen single rooted human teeth were endodontically treated and 2 mm diameter glass fiber-reinforced composite posts were cemented in the root canal. In the first group Futurabond DC without silane, in the second group the same luting material after silane treatment of the posts, and in the third group Clearfil DC Core System without silane were used to lute the posts. After complete setting of the luting agents three 2-mm-thick slices were obtained from the cervical, middle, and apical regions of the roots. The specimens were subjected to push-out test in special equipment. Bond strength data were analyzed with analysis of variance tests. Results The Rebilda posts cemented with Futurabond DC without silane had the highest push-out bond strength at the coronal region (164.71 N ± 72.12), while the posts cemented with Clearfil without silane had the lowest value at the apical region (94.86 N ± 34.14). Silane had no significance on the push-out bond strength (p = 0.909); however, the root canal dentin regions had a significant effect (p &lt; 0.010). Conclusion This study did not show any significant differences among different luting protocols. The bond strength was significantly higher in the coronal region due to the greater cemented surface area and the difference in dentin structure. Clinical significance Based on the results of the push-out tests, the retention of the posts did not depend on the luting methods; however, the region of the root canal played a significant role. How to cite this article Rajnics Z, Marada G, Moetaz E, Radnai M. Effects of Silane on the Push-out Bond Strength of Fiber-reinforced Resin Posts luted with different Self-adhesive Resin Cements. Int J Experiment Dent Sci 2017;6(1):22-25.

Evaluation of calcium silicate cement bond strength after using gutta-percha solvents.

To determine the effect of different gutta-percha solvents (chloroform, Endosolv E, orange oil, and eucalyptol) on the push-out bond strength of calcium silicate cements (CSCs; white mineral trioxide aggregate [WMTA]; capsule-form mineral trioxide aggregate [CMTA], and Biodentine). One hundred and fifty extracted single-rooted human mandibular premolars were sectioned into 3-mm-thick slices. The canal lumens were enlarged for 1.35-mm-diameter standardized cavities. The samples were randomly divided into five groups (n = 30) according to the solvent type: G1, chloroform; G2, Endosolv E; G3, eucalyptol; G4, orange oil; G5, no solvent (control). After application of the solvents for 5 min, the specimens were divided into three subgroups (n = 10): (i) WMTA, (ii) CMTA, and (iii) Biodentine. The push-out bond strength was measured. Two-way ANOVA analysis of variance and post hoc Tukey tests were used for analyses (P = 0.05). The highest push-out bond strength was observed in the Biodentine (P < 0.05), and the values of WMTA and CMTA were not significantly different in all solvent groups (P > 0.05). There were no statistically significant differences among the gutta-percha solvents and control group in WMTA (P > 0.05). Gutta-percha solvents used during retreatment decreased the bond strength of Biodentine and CMTA to root dentin. The bond strength of WMTA was not affected by the use of gutta-percha solvents.

Comparative evaluation of push-out bond strength of resin-based sealer and mineral trioxide aggregate-based sealer after using normal saline and 2% chlorhexidine as a final irrigant: In vitro study

Aim: The aim of this study was to compare the push-out bond strengths of a resin-based sealer and a mineral trioxide aggregate (MTA)-based sealer after using normal saline and 2% chlorhexidine (CHX) as the final irrigant. Materials and Methods: Fifty percent of the samples were irrigated with 2% CHX, and other 50% samples were irrigated with normal saline as the final irrigant. Each set of twenty samples was then further split into groups based on the sealer used. For Group 1 - AH Plus® (Dentsply, Maillefer, Ballaigues, Switzerland), a resin-based sealer was used after using normal saline as the final irrigant (n = 10). In Group 2 an MTA-based sealer was used after using normal saline as the final irrigant (n = 10). In Group 3, AH Plus® (Dentsply, Maillefer, Ballaigues, Switzerland) was used after using 2% CHX as the final irrigant (n = 10). In Group 4, an MTA-based sealer was used after using 2% CHX as the final irrigant (n = 10). After obturation, all the samples were cut perpendicular to their long axis to obtain slices of 3mm each from the coronal and middle third. The discs were then subjected to assess the push-out bond strength by using the Universal Testing Machine. Results: AH Plus® (Dentsply, Maillefer, Ballaigues, Switzerland) showed a significant higher push-out bond strength as compared to the MTA-based sealer after using both saline and 2% CHX. The highest Push-Out Bond Strength was seen with AH Plus® (Dentsply, Maillefer, Ballaigues, Switzerland) after using 2% CHX. Conclusion: AH Plus® (Dentsply, Maillefer, Ballaigues, Switzerland) after using CHX as the final irrigant has shown the best result among all the groups.

The effect of plasma surface treatment on push-out bond strength of fiber-reinforced posts to root canal dentin

Objectives : This study evaluated the effect of surface treatment with plasma or sandblasting on push-out bond strength of fiber post bonded to root canal dentin. Methods : Crowns of 50 teeth were sectioned and their root canals were instrumented, obturated and received post-space preparations. The roots were equally divided into five groups according to post surface treatment. Posts were surface treated with oxygen plasma in Group 1 and argon plasma in Group 2. Post surfaces were treated with sandblasting in Group 3 and silanized after sandblasting in Group 4. In control group (Group 5), posts were cemented to the canal wall without surface treatment. After post cementation, push-out test was used to evaluate the bond strength of fiber post bonded to root canal dentin. Data were statistically analyzed using Kruskal-Wallis and Mann-Whitney tests (α = 0.05). Results : Oxygen plasma revealed the significantly highest push-out bond strength of all groups ( P Conclusions : Oxygen plasma treatment of fiber post recorded the highest bond strength to root canal dentin followed by sandblasting. Silanization and Argon plasma did not play a significant role in enhancing bond strength of fiber posts to canal dentin. Clinical significance: Oxygen plasma surface treatment offered the highest resistance to displacement of fiber posts. Clinical trials involving plasma technique are indicated.

Effect of medicaments used in endodontic regeneration technique on push-out bond strength of MTA and Biodentine

ABSTRACTThe aim of the present study was to evaluate the effect of the intracanal medicaments used in regenerative endodontic treatment on push-out bond strength (PBS) of mineral trioxide aggregate (MTA) and Biodentine (BD). The root canals of 102 maxillary incisors were enlarged to simulate immature roots and were randomly divided into three groups (n = 34): a control group (no intracanal medicament) and two test groups, subjected to calcium hydroxide (CH) or triple antibiotic paste (TAP) medication for two weeks. After the medication removal, each group was divided in two subgroups and the coronal portion of each canal was filled with MTA or BD. After one week of storage, the coronal region of each root was horizontally sectioned and push-out test was performed. Data were analyzed by two-way analysis of variance and the Tukey post hoc test (P = 0.05). PBS values were significantly affected by the type of material (P < 0.001) and the type of medication used (P = 0.049), but no interaction was found (P = 0.97). The BD group showed significantly higher push-out resistance values than those of the MTA group (P < 0.001). TAP showed the lowest PBS values, which were significantly lower than those of the control group (P = 0.043) but not than those of CH (P = 0.229). After a two-week application period, TAP seemed to decrease the PBS of both cements, while CH did not. BD appeared to have higher PBS compared to MTA, regardless of medication.

Evaluation of Effects on the Adhesion of Various Root Canal Sealers after Er:YAG Laser and Irrigants Are Used on the Dentin Surface

IntroductionThe aim of this study was to evaluate the bond strength of various root canal sealers after various irrigation solutions and Er:YAG laser irradiation were used on root canal dentin. MethodsOne hundred fifty freshly extracted human maxillary single-rooted teeth were used in this study. Teeth were sectioned transversally 4 mm below the cementoenamel junction. The root canal of each specimen was prepared using a tapered bur. Teeth were divided into 3 main groups by sealer (AH Plus Jet [Dentsply DeTrey, Konstanz, Germany], EndoSequence BC Sealer [Brasseler, Savannah, GA], and Real Seal [SybronEndo, Orange, CA]) and then divided into 5 subgroups by dentin treatment (distilled water, calcium hydroxide, sodium hypochlorite, EDTA, and Er:YAG laser). The specimens were placed immediately at 37°C and 100% humidity for 1 week. Then, the push-out test was applied. The maximum failure load was recorded in newtons and was used to calculate the push-out bond strength in MPa. Then, 3 random specimens from each group were examined under scanning electron microscopy. ResultsThe resin root canal sealers had higher push-out bond strength than the bioceramic sealer, and the differences were statistically significant (P < .05) except in the sodium hypochlorite groups. The EDTA and Er:YAG laser applications removed the smear layer and increased the bond strength. The highest adhesion was observed in EDTA groups when each sealer was evaluated in itself. ConclusionsThe bonding strength of root canal sealers is influenced by their properties and various dentin surface treatments. The scanning electron microscopic study showed that although the dentinal tubules were open, at the profile examination the sealers did not penetrate into the dentin canals in all specimens.

Effect of acidic environment on the push-out bond strength of calcium-enriched mixture cement.

This laboratory study was performed to evaluate the effect of different acidic pH values on the push-out bond strength of calcium-enriched mixture (CEM) cement. Forty-eight root dentin slices were obtained from freshly extracted single rooted human teeth and their lumen were instrumented to achieve a diameter of 1.3 mm. Then, CEM cement was mixed according to manufacturers' instruction and placed in the lumens with minimal pressure. The specimens were randomly divided into four groups (n=12) which were wrapped in pieces of gauze soaked in either synthetic tissue fluid (STF) (pH=7.4) or butyric acid which was buffered at pH values of 4.4, 5.4 and 6.4. They were then incubated for 4 days at 37°C. The push-out test was performed by means of the universal testing machine. Specimens were then examined under a digital light microscope at 20× magnification to determine the nature of the bond failure. The data were analyzed using the Kruskal-Wallis test followed by Dunn's test for pairwise comparisons. The highest push-out bond strength (10.19±4.39) was seen in the pH level of 6.4, which was significantly different from the other groups (P<0.05). The values decreased to 2.42±2.25 MPa after exposure to pH value of 4.4. Lower pH value of highly acidic environments (pH=4.4), adversely affects the force needed for displacement of CEM cement; while in higher pH values (pH=6.4) the bond-strength was not affected. CEM cement is recommended in clinical situations where exposure to acidic environment is unavoidable.

Push-out bond strength of different mineral trioxide aggregates.

Objective:This study was aimed to evaluate and to compare the push-out bond strength of different brands of mineral trioxide aggregate (MTA) with a calcium enriched mixture cement (CEM).Materials and Methods:Fifteen extracted, single-rooted human teeth were used. The middle-third of the roots were sliced perpendicular to the long axis into 1.00 ± 0.05 mm thick serial slices (15 root × 4 slice = 60 specimen). The specimens were then divided into three groups (n = 20). The standardized root discs were filled with white CEM, ProRoot MTA, MTA-Angelus and wrapped in a serum-soaked gauze. After 3 days at relative humidity, the push-out bond strengths were measured with a universal testing machine. Data were analyzed using one-way analysis of variance and post hoc Tukey tests.Results:The mean push-out bond strength value of the ProRoot MTA group (12.7 ± 2.5 MPa) was the highest and statistically significant difference was recorded between ProRoot MTA and other groups (P < 0.001). There was no significant difference between the mean bond strength of CEM cement (4.6 ± 1.1 MPa) and MTA-Angelus (4.5 ± 1.5 MPa) (P = 0.982).Conclusion:The push-out bond strength of MTA was changed with the brands and ProRoot MTA had the highest push-out bond strength.

Effect of surface treatment and type of cement on push-out bond strength of zirconium oxide posts

The effect of the surface treatment of zirconium oxide posts on their push-out bond strength is controversial. The purpose of this study was to compare the effects of 2 surface treatments on the bond strength of zirconium oxide posts cemented with different cements and to assess the failure mode. Seventy extracted human teeth were divided into 7 groups (n=10). Custom zirconium oxide posts (Cercon; Degudent) were fabricated for 6 groups. Posts in 3 groups were airborne-particle abraded (A). Posts in the other 3groups were tribochemical silica coated (T). Three cements were used. Zinc phosphate cement was used to cement the zirconium oxide posts in groups AZ and TZ, RelyX ARC cement was used in groups ARA and TRA, and RelyX Unicem cement was used in groups ARU and TRU. Group C contained custom metal posts cemented with zinc phosphate cement. Specimens were horizontally sectioned into 3 sections and subjected to a push-out test. A mixed model analysis of variance, 1-way ANOVA, and the Tukey multiple comparison tests were used for statistical analysis. The highest push-out bond strength was recorded for Group ARU (21.03 MPa), and the lowest was recorded for Group ARA (7.57 MPa). No significant difference in push-out bond strength was found among the different surface treatments and root regions (P>.05). The type of cement had a significant effect on the push-out bond strength of zirconium oxide posts (P=.049). RelyX Unicem cement recorded (19.57 ±8.83 MPa) significantly higher push-out bond strength compared with zinc phosphate (9.95 ±6.31 MPa) and RelyX ARC cements (9.39 ±5.45 MPa). Adhesive failure at the post-cement interface was recorded for 75% of the posts cemented with zinc phosphate and RelyX ARC cements, while mixedfailure was recorded for 75% of the posts cemented with RelyX Unicem cement. The type of cement used resulted in a statistically significant difference in the push-out bond strength of zirconium oxide posts, while both the surface treatment and root region resulted in no statistically significant effect after artificial aging. RelyX Unicem cement had significantly higher push-out bond strength than did zinc phosphate and RelyX ARC cements.

An in vitro assessment of gutta-percha coating of new carrier-based root canal fillings.

The first aim of this paper was to evaluate the push-out bond strength of the gutta-percha coating of Thermafil and GuttaCore and compare it with that of gutta-percha used to coat an experimental hydroxyapatite/polyethylene (HA/PE) obturator. The second aim was to assess the thickness of gutta-percha around the carriers of GuttaCore and HA/PE obturators using microcomputed tomography (μCT). Ten (size 30) 1 mm thick samples of each group (Thermafil, GuttaCore, and HA/PE) were prepared. An orthodontic wire with a diameter of 0.5 mm was attached to the plunger of an Instron machine in order to allow the push-out testing of the gutta-percha coating. Five samples of (GuttaCore and HA/PE) were scanned using μCT. The data obtained were analysed with one-way analysis of variance and Tukey post hoc test. HA/PE obturators exhibited significantly higher push-out bond strength (P < 0.001) determined at 6.84 ± 0.96 than those of Guttacore around 3.75 ± 0.75 and Thermafil at 1.5 ± 0.63. GuttaCore demonstrated significantly higher bond strength than Thermafil (P < 0.001). μCT imaging revealed that the thickness of gutta-percha around the experimental HA/PE carrier was homogeneously distributed. The bondability and thickness of gutta-percha coating around HA/PE carriers were superior to those of GuttaCore and Thermafil obturators.