Significant Differences In Bond Strength Research Articles

Comparison of the effect of hydrogel and solution forms of sodium ascorbate on orthodontic bracket-enamel shear bond strength immediately after bleaching: Anin vitrostudy

This study compared the effects of hydrogel and solution forms of sodium ascorbate (SA) with two different application times on bracket bond strength subsequent to bleaching. A total of 72 sound premolars were randomly divided into six groups (n = 12): An unbleached control group (group one) and five experimental groups of carbamide peroxide. Specimens in group two were bonded immediately after bleaching; specimens in groups three and four were bleached, then treated with SA solution for ten minutes and three hours, respectively, and then bonded. In groups five and six, SA hydrogel was used and the specimens were prepared similar to groups three and four, respectively. Following debonding, bond strengths were recorded in MPa. To evaluate the amount of resin left on the enamel surfaces, adhesive remnant index (ARI) scores were used. The bond strength data were analyzed with ANOVA and pairwise comparisons were made by Tukey test. The ARI data were subjected to Kruskal-Wallis test and two-by-two comparisons were made by the Mann-Whitney U test. There were significant differences in bond strengths between the groups ( P < 0.0005). However, the differences between groups three, four, five and six were not significant. Furthermore, there were no significant differences between group one and groups four and six, whereas the differences between the other groups were significant ( P < 0.05). Regarding ARI, there were significant differences among the groups ( P = 0.004). Bleaching significantly decreased the bracket bond strength. Compromised bonding was reversed with a three-hour application of both forms of SA.

Effect of chlorhexidine concentration on the bond strength to dentin in primary teeth

PURPOSE: To evaluate the effect of the use of 0.5% and 2% chlorhexidine digluconate on the immediate bond strength of a conventional adhesive system to dentin in primary teeth. METHODS: Twenty-one healthy primary molars were divided into three groups (n=7), being one control (A) and two experimental groups (B and C). After dentin exposure, in Group (A) the adhesive procedure was performed using 37% phosphoric acid gel (15 s); dentin was washed (15 s), air dried (30 s) and rehydrated with water. Groups B and C followed similar procedures but for re-hydration with 0.5% and 2% chlorhexidine, respectively, for 30 s. A resin composite block was built simulating a restoration, and the teeth were stored in distilled water at 37°C for 24 h before the microtensile bond strength test. The bond strength data were analyzed by analysis of variance. RESULTS: No statistically significant difference in bond strength was found among the tested groups (P>0.05) CONCLUSION: The 0.5% and 2% concentrations of chlorhexidine presented similar behavior and caused no adverse effects on the bond strength to dentin in primary teeth.

Bond strength of different bonding systems to the lingual surface enamel of mandibular incisors

Objective: The aim of this study was to determine whether different types of adhesive systems and enamel- protective agents will affect the tensile bond strength of lingual brackets. Methods: A total of 75 extracted mandibular incisors were randomly divided into 5 groups and lingual brackets were bonded. Group 1 specimens received Transbond XT (3M Unitek, Monrovia, CA, USA), Group 2 required the application of a fluoride- releasing resin (Ortho-coat, Pulpdent, Watertown, MA, USA) with Transbond XT, Group 3 specimens received a chlorhexidine varnish (Cervitec Plus, Ivoclar Vivadent, Schaan, Lichtenstein) with Transbond XT. In Group 4, a light-cured orthodontic adhesive (Aegis Ortho, Bosworth, Skokie, USA) was applied and in Group 5, an antimicrobial self-etching primer (Clearfil Protect Bond, Kuraray, Osaka, Japan) was used. Results: There were no significant differences in bond strength whether fluoride-releasing resin or chlorhexidine varnish were used or not. Group 5 had significantly higher bond strength and adhesive remnant index (ARI) values than other groups (p ＜ 0.001). The application of enamel-protective products did not have an adverse affect on the bond strength of lingual brackets. Conclusions: These products might provide benefits both for the patient and the clinician, by supporting the oral hygiene during lingual orthodontic treatment. The higher ARI score may be beneficial for Clearfil Protect Bond but its excessive bond strength should be considered in clinical practice, especially where the enamel is thin. (Korean J Orthod 2010;40(4):260-266)

Bond Strength Of Different Artificial Tooth Manufacturing To Microwave Cured Acrylic Denture Base

AIMS of this study are to investigate the bond strength and mode of failure of different tooth materials with and without surface treatment to acrylic resin denture base cured by microwave in relation to wa-ter bath techniques. MATERIALS AND METHODS: One hundred sixty samples of five different brands of acrylic teeth were divided into four groups (untreated and treated groups each of these were cured by water bath or microwave techniques). The bond strength between acrylic tooth and denture base resin was measured in shear mode by using unconfined compression machine. The shear bond strength (SBS) in MPa was calculated, debonded surfaces were examined using visual examination and reflecting light microscope . Analysis of variance (ANOVA) and Duncan’s multiple range tests were used for statistical analysis. RESULTS: there was a significant difference in bond strength of acrylic denture base to different tooth materials (P < 0.001). CONCLUSIONS: SBS of acrylic teeth treated by monomer surface treatment for 180 seconds to microwave cured resin was significantly higher than that of water – bath cured resin, and cross – linked acrylic teeth showed lowest SBS compared to other type of acrylic teeth.Key words: Microwave, Bond strength, Cross – linked acrylic teeth.

Effect of Long-Term Storage Temperatures on the Bond Strength of Self-Etch Adhesives

Manufacturers often recommend refrigerated storage of self-etching enamel and dentin adhesives. The purpose of this study was to compare the shear-bond strength of composite resin to dentin using two different self-etching adhesives after extended storage at room or refrigerated temperatures. One- and two-step self-etching bonding agents were stored separately at room (23 degrees C) or refrigerated temperatures (5 degrees C) per manufacturer recommendations for 1, 4, or 18 months before testing. After each time period, composite resin was bonded to the dentinal surface of extracted human third molars using a mold and tested in shear on a universal-testing machine. Data were analyzed with analysis of variance/Tukey's test. No significant difference in bond strengths was found on the basis of storage temperature for either adhesive type. The one-step adhesive had a significant loss in bond strength over the 18 months of storage. However, the two-step self-etch adhesive had no loss in bond strength, regardless of storage temperature.

Measurement of shear bond strength to intact dentin

Previously, we reported that the integrity of a resin composite restoration deteriorated when the dentin cavity wall was decalcified by conditioning. In this study, to evaluate the bonding between dentin adhesive and non-decalcified dentin surface, we experimented with a novel method of using a high-pressure water spray device to prepare smear layer-free dentin surfaces. When the smear layer was removed, shear bond strength significantly increased regardless of the removal method employed. Further, with glyceryl monomethacrylate (GM) priming, no significant differences in bond strength were observed among these smear layer removal methods: ethylenediamine tetraacetic acid (EDTA) conditioning, phosphoric acid conditioning, and removal by water spray. It was also found that GM priming was key to achieving marginal integrity, whereas contraction gap width increased with phosphoric acid conditioning. It was thus concluded that the efficacy of a dentin adhesive should be evaluated by consistently observing the contraction gap in three-dimensional cavities rather than by mere measurement of bond strength to a flat dentin surface.

Effect of water contamination on the shear bond strength of five orthodontic adhesives

To evaluate the shear bond strength and site of failure of brackets bonded to dry and wet enamel. 50 teeth were divided into ten groups of 5 teeth each (10 surfaces). In half the groups enamel was kept dry before bonding, and in the other half distilled water was applied to wet the surface after etching. The following groups were established: 1) Acid/Transbond-XT (dry/wet) XT; 2) Transbond Plus Self Etching Primer (TSEP)/Transbond-XT paste (dry/wet); 3) Concise (dry), Transbond MIP/Concise (wet), 4) FujiOrtho-LC (dry/wet); 5) SmartBond (dry/wet). Brackets were bonded to both buccal and lingual surfaces. Specimens were stored in distilled water (24 hours at 37 degrees C) and thermocycled. Brackets were debonded using a Universal testing machine (cross-head speed 1 mm/min). Failure sites were classified using a stereomicroscope. No significant differences in bond strength were detected between the adhesives under wet and dry conditions except for SmartBond, whose bond strength was significantly lower under dry conditions. For all the adhesives most bond failures were of mixed site location except for Smartbond, which failed at the adhesive-bracket interface. Under wet conditions the bonding capacity of the adhesives tested was similar than under dry conditions, with the exception of SmartBond which improved under wet conditions.

In Vitro Tensile Bond Strength of Denture Repair Acrylic Resins to Primed Base Metal Alloys Using Two Different Processing Techniques

Approximately 38% of removable partial denture (RPD) failures involve fracture at the alloy/acrylic interface. Autopolymerizing resin is commonly used to repair RPDs. Poor chemical bonding of repair acrylic to base metal alloys can lead to microleakage and failure of the bond. Therefore, ideal repair techniques should provide a strong, adhesive bond. This investigation compared the tensile bond strength between cobalt-chromium (Super Cast, Pentron Laboratory Technologies, Llc., Wallingford, CT) and nickel-chromium (Rexalloy, Pentron Laboratory Technologies, Llc.) alloys and autopolymerized acrylic resin (Dentsply Repair Material, Dentsply Int, Inc, York, Pa) using three primers containing different functional monomers [UBar (UB), Sun Medical Co., Ltd., Shiga, Japan: Alloy Primer (AP) Kuraray Medical Inc., Okayama, Japan; and MR Bond (MRB) Tokyuyama Dental Corp., Tokyo, Japan] and two processing techniques (bench cure and pressure-pot cure). One hundred and twenty eight base metal alloy ingots were polished, air abraded, and ultrasonically cleaned. The control group was not primed. Specimens in the test groups were primed with one of the three metal primers. Autopolymerized acrylic resin material was bonded to the metal surfaces. Half the specimens were bench cured, and the other half were cured in a pressure pot. All specimens were stored in distilled water for 24 hours at 37 degrees C. The specimens were debonded under tension at a crosshead speed of 0.05 cm/min. The forces at which the bond failed were noted. Data were analyzed using ANOVA. Fisher's PLSD post hoc test was used to determine significant differences (p < 0.05). Failure modes of each specimen were evaluated under a dissecting microscope. Significant differences in bond strength were observed between combinations of primers, curing methods, and alloys. Primed sandblasted specimens that were pressure-pot-cured had significantly higher bond strengths than primed sandblasted bench-cured specimens. The pressure-pot-curing method had a significant effect on bond strength of all specimens except Co-Cr alloy primed with UB. The highest bond strength was observed for both Co-Cr and Ni-Cr alloys that were sandblasted, primed with MRB, and pressure-pot cured. Co-Cr alloys primed with UB had the lowest bond strength whether bench cured or pressure-pot cured. Primed specimens generally experienced cohesive bond failures within the primer or acrylic resin. Nonprimed specimens generally experienced adhesive bond failures at the resin/metal interface. Within the limitations of this study, MRB provided the highest bond strength to both Ni-Cr and Co-Cr alloys. Generally, bond strength improved significantly when specimens were primed. Pressure-pot curing, in most cases, resulted in higher bond strength than bench curing. The results of this in vitro study suggest that MRB metal primer can be used to increase bond strength of autopolymerized repair acrylic resin to base metal alloys. Curing autopolymerized acrylic under pressure potentially increases bond strength.

Bond strengths of an antibacterial monomer-containing adhesive system applied with and without acid etching for lingual retainer bonding

The aim of this study was to test the null hypothesis that there is no significant difference in bond strength and failure site location of composite bonded to etched and unetched enamel with an antibacterial monomer-containing adhesive and a conventional lingual retainer adhesive system. The crowns of 60 extracted lower human incisors were mounted in acrylic resin leaving the lingual surface of the crowns parallel to the base of the moulds. The teeth were randomly divided into three equal groups: two experimental and a control. Conventional lingual retainer composite (Transbond LR) and antibacterial monomer-containing adhesive (Clearfil Protect Bond), with or without prior etching, were applied to the lingual surface of the teeth by packing the material into cylindrical plastic matrices (Ultradent) with an internal diameter of 2.34 mm and a height of 3 mm to simulate lingual retainer bonding. The shear bond data were analysed using analysis of variance and Tukey's tests. Fracture modes were analysed by chi-square test. Statistical analysis showed that the bond strengths of the control (Transbond LR, mean: 24.77 +/- 9.25 MPa) and Clearfil Protect Bond with etching, (mean: 20.24 +/- 8.5 MPa) were significantly higher than Clearfil Protect Bond without etching, (mean: 12.56 +/- 6.93 MPa). In general, a greater percentage of the fractures were adhesive, at the tooth-composite interface (60-65 per cent). No statistically significant difference was found among the groups. The hypothesis is thus rejected. Within the limits of this in vitro model, antibacterial monomer-containing self-etch adhesive with acid etching did not significantly affect shear bond strength when compared with the control. However, the same adhesive used without acid etching resulted in a significant decrease in bond strength.

Avaliação da influência dos tipos de tratamento superficial da porcelana glazeada na colagem de braquetes ortodônticos

OBJETIVO: o objetivo deste trabalho foi avaliar a influência do tipo de tratamento superficial da porcelana na resistência adesiva da colagem de braquetes ortodônticos e o modo de fratura após a descolagem. METODOLOGIA:foram confeccionados 80 corpos-de-prova de porcelana, divididos em quatro grupos (n = 18) de acordo com os diferentes tratamentos de superfície: (G1) ponta diamantada; (G2) ponta diamantada e silano; (G3) ácido hidrofluorídrico e (G4) ácido hidrofluorídrico e silano. Após o preparo das superfícies, braquetes Edgewise (Morelli) foram colados com resina (Transbond XT, 3M) e submetidos ao teste de cisalhamento. Os resultados foram avaliados estatisticamente pelo teste de Kruskal-Wallis. RESULTADO: o grupo G1 apresentou uma média de resistência de 3,35, o G2 3,97, o G3 2,56 e o G4 3,10. CONCLUSÃO: constatou-se que não houve diferença estatisticamente significativa na resistência adesiva do braquete entre os tipos de tratamentos estudados (p &gt; 0,05) e os modos de fratura ocorreram, em sua grande maioria, na interface braquete/resina. Este estudo indica que todos os tipos de tratamentos apresentados são eficientes para a colagem.

Translucent fiber post cementation using light- and dual-curing adhesive techniques and a self-adhesive material: Push-out test

Objectives To compare, by means of the push-out test, the interfacial strength of two dual resin cements and one light-curing cement when used in translucent fiber post cementation. Methods Thirty-nine, endodontically treated, single canal, extracted human bicuspids were selected. Translucent fiber posts (RelyX Fiber Post) were luted into the root canal using three resinous luting systems ( n = 13). Dual-curing technique (DC): the specimens were treated with Excite DSC and RelyX ARC, which were light-cured simultaneously through the post for 60 s. Self-adhesive dual-curing technique (SADC): the specimens were treated with RelyX Unicem, which was light-cured through the post for 60 s. Light-curing technique (LC): the specimens were treated with Excite DSC and Tetric Flow, which were simultaneously light-cured through the post for 60 s. The specimens were transversally sectioned into six slices in order to perform the push-out test. Data were analyzed by two-way ANOVA followed by the Tukey–Kramer test for post-hoc comparisons at α = 0.05. Results At every region, results did not show any statistical difference between the DC and LC techniques. With the LC technique bond strength values were lower at the apical region than those recorded at the coronal and middle regions. At the coronal and middle regions, bond strength values for the SADC technique were lower than those resulting when using the other two techniques. At the apical region, there was not significant difference in bond strength between the luting techniques tested. Conclusions The interfacial strength between light-curing cement and root canal is equivalent to the interfacial strength between dual-curing cement and root canal.

Effects of different silanes and acid concentrations on bond strength of brackets to porcelain surfaces

The aim of this study was to determine the optimum silane-coupling agent and the optimum concentration of acid agent when bonding to porcelain surfaces. Eighty deglazed feldspathic porcelain discs with a diameter of 10 mm and a thickness of 2 mm mounted in acrylic resin blocks were randomly divided into four groups. In groups 1 and 2, the porcelain surfaces were etched with 9.6 per cent hydrofluoric (HF) acid and in groups 3 and 4 with 5 per cent HF acid. In groups 1 and 3, the Dynalock maxillary central incisor brackets were bonded with Pulpdent silane and Unite bonding adhesive and in groups 2 and 4 with Reliance silane and Unite. Shear forces were applied to the samples using an Instron universal test machine. The non-parametric Kruskal-Wallis test was used to determine significant differences in bond strengths between the four groups and Dunn's multiple comparison test to compare subgroups. The mean bond strengths and standard deviations of groups 1 to 4 were 5.51 +/- 1.19, 6.54 +/- 0.002, 4.55 +/- 1.93, and 6.39 +/- 0.45 MPa, respectively. Specimens bonded with Reliance showed a statistically significantly higher in vitro bond strength than those bonded with Pulpdent. The concentration of etching gels did not result in any statistically significant difference on the in vitro bond strength when evaluated separately.

The Influence of Adhesive Luting Systems on Bond Strength and Failure Mode of an Indirect Micro Ceramic Resin-based Composite Veneer

This study evaluated the bond strength and failure mode of enamel/resin-based composite veneers bonded with three different dual cured resin adhesive systems. Standard preparations for laminate veneer restorations were made on 30 human central incisors using depth cutting burs (0.5 mm depth at the incisal area and 0.3 mm at the gingival area). Thirty indirect laminates were prepared using a highly filled polymeric material (GC Gradia) according to the manufacturer's instructions. After sandblasting the fitting surfaces, the specimens were randomly divided into three groups (ten per group) based on the type of resin cement luting systems; Excite/Variolink II, Single Bond/Rely X Veneer Cement, and Clearfil New Bond/Panavia F. The specimens were stored in water at 37 degrees C for 48 hours. Fracture testing was performed using a universal testing machine where the load was applied from the incisal direction at 135 degrees to the long axis of the tooth (0.5 mm/min). The one-way analysis of variance (ANOVA) and Chi-Square tests were used for statistical analysis at a significance level of p > 0.05. The ANOVA showed no significant difference was found among the groups (P > 0.05). Indirect veneers showed mean enamel bond strength of 114.4 +/- 48 N, 159.7 +/- 83.4 N, and 126.1 +/- 51.7 N with Variolink II, Rely X veneer cement, and Panavia F, respectively. The Chi-Square tests showed no significant difference regarding the failure mode frequencies in different types of failure in the three groups (p>0.05). The failure mode analysis showed mainly adhesive failure in the resin cement/laminate interface in all groups. There was no significant difference in bond strength of veneers with the three different resin cements tested. In addition, there was no significant difference in the frequency of the failure mode in each type of failure among the three test groups. The failure analysis revealed mainly an adhesive failure at the resin cement/veneer interface. The results of this study suggest the use of Excite/Variolink, Single Bond/RelyX, or Clearfil New Bond/Panavia F are all appropriate choices for luting of indirect micro ceramic resin-based composite veneers in terms of bond strength and failure mode.

Two-year Water Degradation of Self-etching Adhesives Bonded to Bur Ground Enamel

To evaluate the effect of water storage on the microshear bond strength to ground enamel of three "all-in-one" self-etch adhesives: Futurabond DC, Clearfil S Tri Bond and Hybrid bond; a self-etching primer; Clearfil SE Bond and an etch-and-rinse adhesive system, Admira Bond. Sixty human molars were used. The root of each tooth was removed and the crown was sectioned into two halves. The convex enamel surfaces were reduced by polishing on silicon paper to prepare a flat surface that was roughened with a parallel-sided diamond bur with abundant water for five seconds. The bonding systems were applied on this surface. Prior to adhesive curing, a hollow cylinder (2.0 mm in height/0.75 mm in internal diameter) was placed on the treated surfaces and cured. A resin composite was then inserted into the tube and cured. For each adhesive, two procedures were carried out: A--the specimens were kept in water for 24 hours, then the tube was removed and the microshear bond strength was determined in a universal testing machine at a crosshead speed of 0.5 mm/minute; B--the specimens were stored in water for two-years before microshear testing. The fractured surface of the bonded specimens after each test procedure was examined by SEM. For the 24-hour control, there was no significant difference in bond strength between the tested adhesives. After two years of water storage, the bond strength of Admira Bond, Clearfil SE Bond and Futurabond DC decreased, but the reduction was not significantly different from that of 24 hours. For Clearfil S Tri Bond and Hybrid Bond, the bond strengths were significantly reduced compared to their 24-hour results.

Four-year water degradation of a total-etch and two self-etching adhesives bonded to dentin

Objectives To evaluate effect of direct and indirect water storage on the microtensile dentin bond strength of one total-etch and two self-etching adhesives. Methods The adhesive materials were: one total-etch adhesive; ‘Admira Bond’ and two self-etch adhesives; ‘Clearfil SE Bond’ and ‘Hybrid Bond’. Freshly extracted human third molar teeth were used. In each tooth, a Class I cavity (4 mm × 4 mm) was prepared in the occlusal surface with the pulpal floor extending approximately 1 mm into dentin. The teeth were divided into three groups ( n = 18). Each group was restored with the resin composite ‘Clearfil APX’ using one of the tested adhesives. For each experimental group 3 test procedures ( n = 6) were carried out: Procedure A: the teeth were stored in water for 24 h (control), then sectioned longitudinally, buccolingually and mesiodistally to get rectangular slabs of 1.0–1.2 mm thickness on which a microtensile test was carried out. Procedure B: the teeth were also sectioned; however, the slabs were stored in water at 37 °C for 4 years before microtensile testing (direct water storage). Procedure C: the teeth were kept in water at 37 °C 4 years before sectioning and microtensile testing (Indirect water storage). During microtensile testing the slabs were placed in a universal testing machine and load was applied at cross-head speed of 0.5 mm/min. Results For the 24 h control, there was no significant difference in bond strength between the three tested adhesives. After 4 years of indirect water storage, the bond strength decreased but the reduction was not significantly different from those of 24 h. After 4 years of direct water storage, the bond strengths of all tested adhesives were significantly reduced compared to their 24 h results. Conclusion All the tested adhesives showed no reduction in bond strength after indirect water exposure for 4 years. After 4-year direct water exposure, the bond produced by all tested adhesives was unable to resist deterioration.

Bond Strength of an Amorphous Calcium Phosphate–Containing Orthodontic Adhesive

To determine whether an amorphous calcium phosphate (ACP)-containing adhesive has an acceptable level of shear bond strength to be used as an orthodontic adhesive. Sixty extracted premolars were randomly divided into three groups for orthodontic bonding. Group 1 used a composite resin adhesive (Transbond XT), group 2 was bonded with an ACP-containing adhesive (Aegis Ortho), and group 3 used a resin-modified glass ionomer (Fuji Ortho LC). All bonded teeth were stored in distilled water at 37 degrees C for 40 +/- 2 hours prior to debonding. Shear bond strength and adhesive remnant index (ARI) were recorded for each specimen. The mean shear bond strengths for the three test groups were: group 1 (15.2 +/- 3.6 MPa), group 2 (6.6 +/- 1.5 MPa), and group 3 (8.3 +/- 2.8 MPa). A one-way analysis of variance showed a significant difference in bond strengths between the groups. A post hoc Tukey test showed group 1 to be significantly (P < .001) greater than groups 2 and 3. A Kruskal-Wallis test and a Mann-Whitney U-test showed groups 1 and 3 exhibited lower ARI scores than group 2, but a majority of specimens in each group had greater than 50% of the cement removed along with the bracket during debonding. The ACP-containing adhesive demonstrated a low, but satisfactory bond strength needed to function as an orthodontic adhesive.

Evaluation of the bond strength of different bonding agents to porcelain and metal alloy

This study was carried out with the purpose of testing the bond strength of different bonding agents bonded to different substrates. Substrates consisted of cylindrical specimens of three different materials: porcelain, metal, and a porcelain–metal combination. Specimens were all 10 mm in diameter and 4 mm thick. Surfaces to be bonded were air-abraded with Al 2O 3 and cleaned ultrasonically in distilled water for 10 min. After the preparation of the surface was complete, three different bonding agents were applied to the central region of the substrates. Composite resin of a 3.5 mm diameter and 2 mm thick was applied. All specimens were thermocycled between 5 and 55 °C for 200 cycles with a 30-s dwell time. After thermocycling, specimens were stored at 37 °C in distilled water for an additional 7 days before being subjected to a shear load. Shear testing was conducted Hounsfield test machine. The univariate analysis of variance and the Duncan multiple comparison test were used for statistical assessment. It was found that both type of bonding agents and of substrate led to statistically significant differences in bond strength ( p<0.01). It was found that the highest bond strength was produced by Clearfil and on pure alloy substrate (33.36 MPa) and the lowest bond strength in Single Bond and porcelain–alloy substrate (4.25 MPa).

The Effect of Different Adhesive Systems on the Retention Strength of Bonded Amalgam Restorations

The aim of this study was to evaluate the bond strength of bonded amalgam to dentin when unfilled and filled adhesive systems are employed using different application modes and to compare the adhesives with a cavity varnish and unlined restorations. One hundred and twenty sound third human molar teeth were used in the study. A cylindrical cavity 3.3 mm in diameter was prepared in a cross section of dentin approximately 3.0 mm in thickness. The specimens were divided into six experimental groups (n=20) according to the cavity liner used in the prepared cylindrical cavity: One Coat Bond (O), Scotchbond Multi-Purpose(S) , Panavia 21 (Pa), PQ1 (P), Copalite (C), and the unlined (U) group which served as the control group. Cavity surfaces were treated with the assigned adhesive/liner according to manufacturer's instructions then restored with amalgam. After storage in saline solution for seven days at 37 degrees C, the specimens were subjected to a push-out test at a crosshead speed of 1 mm/min. The mode of failure was assessed by microscopic analysis of the fracture sites. Data were analyzed by analysis of variance (ANOVA) and Duncan Multiple range tests (a=0.05). No significant difference in amalgam-dentin bond strength was found among O (23.47 MPa), S (21.02 MPa), and Pa (20.06 MPa) adhesive groups, but there was a significant difference between each of these groups and the P and C groups. The U group exhibited significantly lower retention than the other groups (P<0.05). Different bond strengths were observed with the different types of dentin bonding agents and liners employed. The lowest bond strength was seen in the U group. A statistically significant difference in bond strength was observed with O, S, and Pa compared to P, but this finding is not sufficient to rely on the bonding of amalgam to dentin, particularly in complex amalgam restorations.

Bond Strengths of Three Different Dentin Adhesive Systems to Sclerotic Dentin

The two-fold aims of this study were: (1) to evaluate the microtensile bond strengths of different adhesive systems to sclerotic and sound palatal dentin; and (2) to observe the respective resin-dentin interfaces. Thirty extracted human incisor teeth were divided into two groups. Group I comprised sclerotic defects in the palatal zone. Group II comprised sound palatal dentin surfaces as control. Each group (n=15) was divided into three subgroups according to dentin adhesive systems: self-etch (Clearfil SE Bond), total-etch (Scotchbond Multi-Purpose Plus), and glass ionomer (Reactmer Bond) adhesive systems. The specimens were subjected to tensile forces. Obtained data were analyzed by two-way ANOVA and post hoc Duncan's test. Fracture sites and resin-dentin interfaces were observed using a light microscope and SEM. With sound dentin, Clearfil SE Bond showed a significantly higher bond strength than the other adhesives (p < 0.05). With sclerotic dentin, although there were no significant differences in bond strength among the adhesives groups (p > 0.05), the bond strength values of Clearfil SE Bond and Scotchbond Multi-Purpose Plus were significantly decreased. On resin-dentin interface observation, different images were presented by different bonding systems.

An in vitro Comparison of the Effect of Three Different Endodontic Medicaments on the Bond Strength of a Resin-based Endodontic Sealer to the Root Canal Dentin

ABSTRACT Objectives The aim of this study was to compare and evaluate the effect of calcium hydroxide [Ca(OH)2], 2% chlorhexidine (CHX) gel, and propolis when used as intracanal medicaments on the bond strength of a resin-based sealer (AH Plus Jet; Dentsply DeTrey, Konstanz, Germany) to the root dentin. Materials and methods Sixty freshly extracted single-rooted human teeth were utilized for this study and the crowns were decoronated. The root canals were instrumented and randomized into four groups according to the medicament used: Group I: Control; group II: Ca(OH)2; group III: CHX; group IV: Propolis. The specimens were stored for 10 days in 100% humidity at 37°C, and the intracanal dressings were removed by rinsing with 10 mL of 17% ethylenediaminetetraacetic acid followed by 10 mL of 2.5% sodium hypochlorite, then obturated with gutta-percha and AH Plus Jet sealer. A push-out test to measure the bond strength between the root canal dentin and the sealer was done. Two-way analysis of variance and Tukey’s post hoc pairwise tests were used for statistical analysis. Results The use of intracanal medicaments had shown to significantly influence the push-out bond strengths of the resin sealer used (p &lt; 0.05). At coronal and middle thirds, there was no significant difference in bond strengths among all the four groups (p &gt; 0.05). At apical third, the mean bond strength value for propolis group was significantly superior when compared with the other three groups (p &lt; 0.05). The CHX group showed higher bond strength values at apical third compared with Ca(OH)2 and control groups, but it was not significant (p &gt; 0.05). Conclusion Propolis showed superior push-out bond strength than CHX, Ca(OH)2, and control groups at apical third, while no significant differences were observed among all the groups at coronal and middle thirds. How to cite this article Shivanna V, Bhargavi R. An in vitro Comparison of the Effect of Three Different Endodontic Medicaments on the Bond Strength of a Resin-based Endodontic Sealer to the Root Canal Dentin. CODS J Dent 2016;8(1):28-32.