Higher Microtensile Bond Strength Research Articles

Effect of Aprotic Solvents on the Microtensile Bond Strength of Composite Core and Fiber-Reinforced Composite Posts.

This investigation evaluated the effects of aprotic solvents, i.e., tetrahydrofuran, pyridine, and morpholine, compared with hydrogen peroxide, on the surfaces of fiber-reinforced composite posts with a composite core based on the microtensile bond strength. In total, 150 FRC Postec Plus posts and 150 D.T. Light-Posts were randomly divided into three groups (non-thermocycling, 5000-cycle, and 10,000-cycle thermocycling groups). Each group was divided into five subgroups according to the post-surface treatment: C, non-treatment group; H2O2, immersed in 35% hydrogen peroxide; THF, immersed in tetrahydrofuran; PY, immersed in pyridine; and MP, immersed in morpholine. The treated specimens were placed in the bottom of a plastic cap and filled with a composite core material in preparation for the microtensile bond test. The data were evaluated using one-way ANOVA and Tukey's test (p < 0.05) as well as an independent t-test (p < 0.05). For the surface roughness, white light interferometry was used for measurement, and the mean surface roughness was analyzed via one-way ANOVA and Tukey's test (p < 0.05). The results showed that, under non-thermocycling conditions, the PY subgroup with D.T. Light-Post had the highest microtensile bond strength, followed by THF, MP, H2O2, and the control groups. For FRC Postec Plus, the PY group had the highest microtensile bond strength, followed by MP, THF, H2O2, and the control groups. Although the thermocycling conditions decreased the microtensile bond strength in all groups, the PY subgroup still had the highest value. An independent t-test revealed that even under all non-thermocycling and 5000- and 10,000-cycle thermocycling conditions, D.T. Light-Post in the PY subgroup displayed significantly higher microtensile bond strengths than FRC Postec Plus in the PY subgroup. While the surface roughness of the fiber-reinforced composite posts showed that the posts treated with pyridine possessed the highest surface roughness for each material type, In conclusion, as an aprotic solvent, pyridine generates the highest microtensile bond strength between the interfaces of composite cores and fiber-reinforced composite posts.

The Effect of Different Sealer Removal Protocols on Micro-Tensile Bond Strength of Single Bond Plus to Dentin Exposed with Different Chemical Root Canal Irrigants: An Ex Vivo Study

Background: Chemical substances used to prepare root canals and their residuals can alter dentin surface composition, affecting restorative systems bonding to dentin. Objectives: This ex vivo study evaluated the effects of different sealer removal methods on the micro-tensile bond strength of dentin surfaces exposed using endodontic irrigants. Methods: A total of 45 extracted healthy mandibular molars were sliced from the occlusal surface to expose their dentin surface and were randomly divided into three main groups (n = 15) based on the irrigants as G1: Distilled water (control), G2: Sodium hypochlorite (NaOCL) 5.25%, and G3: Chlorhexidine (CHX) 2%. AH Plus endodontic sealer, was applied to all exposed dentin surfaces. Each group was divided into four subgroups (SG) according to the sealer removal methods: SG1: No root canal sealer (control), SG2: Moist cotton pellet, SG3: Ethanol 95% saturated cotton pellet, SG4: Round diamond bur. The teeth were restored using single bond plus and Z250 composite and sectioned to prepare sticks for micro-tensile bond testing. Additionally, failure patterns were investigated. Comparison between experimental groups was performed using Kruskal-Wallis H and Dunn's post-hoc tests. The accepted significance level for all tests was P &lt; 0.05. Results: A significant decrease was observed in the micro-tensile bond strength of the control group cleaned with 95% Ethanol saturated cotton pellets. In addition, the highest micro-tensile bond strength was observed in dentin cleaned through a diamond round bur and in the group irrigated with CHX. The failure modes were mainly adhesive. Conclusions: Within this study's limitations, the dentin bond strength is affected by the irrigation protocol and sealer removal method.

A novel glass ionomer cement with silver zeolite for restorative dentistry

ObjectiveTo develop an antimicrobial silver zeolite glass ionomer cement (SZ-GIC) and determine its biocompatibility, physical, adhesive and antibacterial properties. MethodsSilver nitrate and sodium zeolite were used to synthesize silver zeolite (SZ). SZ-GICs were prepared by incorporating SZ into GIC at 5% (SZ-GIC5), 2% (SZ-GIC2), or 1% (SZ-GIC1) by weight, respectively. The SZ-GICs were characterized by evaluating surface morphology, topography and elemental composition. SZ-GICs’ biocompatibility was assessed by evaluating cell cytotoxicity. Their physical properties were determined by testing setting time, compressive strength, flexural strength, water sorption and solubility. Their adhesive property was assessed by evaluating micro-tensile bond strength. Their antibacterial properties were assessed by evaluating biofilm growth kinetic, metabolic activity, viability and morphology. GIC was used as a control. ResultsSZ was a three-dimensional crystalline mineral. SZ-GICs (including SZ-GIC 5, 2 and 1) showed similar surface morphology and topography to GIC. SZ-GIC1 and GIC had no difference in cell cytotoxicity (p>0.05). SZ-GICs and GIC showed no difference in setting time (p>0.05). SZ-GICs had higher compressive and flexural strength than GIC (p<0.05). SZ-GIC2 and SZ-GIC1 showed lower water sorption and solubility than GIC (p<0.05). SZ-GICs had higher micro-tensile bond strength than GIC (p<0.05). Biofilms on SZ-GICs’ surfaces showed lower colony-forming units, decreased metabolic activities, higher percentages of dead cells and more ruptured bacterial cells compared with those on GIC. ConclusionSZ-GIC with silver zeolite at 1% by weight are as biocompatible as conventional GIC. The SZ-GICs have enhanced physical, adhesive and antibacterial properties than GIC. Clinical significanceA silver zeolite glass ionomer cement was developed. The SZ-GICs have great potential for caries prevention and management.

Removal of Different Thicknesses Influences the Repair Bond Strength of Dental Resin Composites

This study investigates the repair bond strength of aged resin composites after removing different thicknesses, determine the repair performance using the same or different resin composites and describe the treated surfaces after ageing. Seventy simulated class I cavities were prepared in extracted human third molars were randomly divided into two groups and restored with a nanofilled (Filtek Z350) or a microhybrid (Clearfil APX) composite. Five specimens without ageing in each group acted as a positive control for microtensile bond strength (MTBS) test. After thermocycling, each group was randomly divided into two subgroups: Group RT1, 1 mm removed and Group RT3, 3 mm removed, followed by roughening. Ten specimens in each subgroup were repaired with the same or different composites, and MTBS tests were conducted. The surface roughness (Sa), and water contact angle of the remaining five specimens in each subgroup were measured. In every combination group, Group RT3 showed significantly higher MTBS values than Group RT1, and identical composite was not compulsory for higher repair bond strength. Removal thickness had no significant effect on the Sa in same composite group. In both the Z350 and APX groups, the water contact angle decreased with increasing removal thickness.

Effect of bioactive glass pretreatment on the durability of dentin bonding interface

To study the effect of bioactive glass (BG) on the dentin bond strength and the microleakage of hybrid layer. In the study, 30 dentin planes were prepared from the third molars with no caries and equally assigned to the control group, BG group, and sodium trimetaphosphate (STMP)-polyacrylic acid (PAA)-BG group (S-P-BG group), randomly. After etched with 35% phosphoric acid, the dentin planes of BG group were pretreated with 0.5 g/L BG, and the dentin planes of S-P-BG group were pretreated with 5% STMP, 5% PAA and 0.5 g/L BG. No additional pretreatment was done to the dentin planes of control group. Then the dentin planes were bonded using 3M Single Bond 2 adhesive to 3M Z350XT composite resin, and cut into 0.9 mm×0.9 mm column samples, which were stored at 37 ℃ artificial saliva (AS). After 24 hours, 1 month, and 3 months, the microtensile bond strength test was performed. The data were analyzed using one-way ANOVA and LSD method. The morphology of the bond fracture interface was observed with scanning electron microscope. Other 27 teeth were collected and the enamel layer and roots cut off, with the pulp chamber exposed. 0.1% rhodamine B was added to the 3M Single Bond 2 adhesive, and then the adhesive was applied to complete the bonding procedures as above. The teeth were stored in 37 ℃ AS for 24 hours, 1 month, 3 months, and then 0.1% sodium fluorescein solution was placed in the chambers and stained for 1 hour. Confocal laser scanning microscopy was used to observe the interface morphology and microleakage of the hybrid layer. At the end of 24 hours and 1 month, there was no significant difference in the microtensile bond strength among the three groups (P>0.05). After 3 months of soaking, the S-P-BG group [(36.91±7.07) MPa] had significantly higher microtensile bond strength than the control group [(32.73±8.06) MPa] (P=0.026); For the control group and the BG group, the microtensile bond strength significantly decreased at the end of 3 months compared with 24 hours (control group: P=0.017, BG group: P=0.01); The microtensile bond strength of S-P-BG group af the end of 3 months had no significant difference in compared with 24 hours [(37.99±7.98) MPa] (P>0.05). Observation of the fracture surface at the 24 hours showed no obvious mineralization in all the three groups. After 1 and 3 months, mineral formation was observed in BG group and S-P-BG group, and no obvious collagen exposure was observed in S-P-BG group. Confocal laser scanning microscopy revealed no obvious differences in the morphology and quantity of the resin tag in the control group, BG group and S-P-BG group. At the end of 24 hours, leakage was found in all the three groups. The microleakage of the control group increased at the end of 3 months, while the microleakage of the BG and S-P-BG groups decreased. BG pretreatment of dentin bonding interface can induce mineralization at the bonding interface and reduce the microleakage of the hybrid layer; pretreating the dentin bonding interface with STMP, PAA and BG may enhance the maintaining of the dentin bonding durability.

Dual modified nanosilica particles as reinforcing fillers for dental adhesives: Synthesis, characterization, and properties

A facile procedure has been devised to develop a novel dentin bonding system containing poly (acrylic acid)-grafted-silanized fumed silica particles as reinforcing filler, with high stability of nanoparticle dispersion and enhanced bond strength and mechanical properties. In the first step, the silanization of fumed silica nanoparticles was performed in the following conditions: (i) ethanol-water solution with a pH of 5 and (ii) cyclohexane with a pH of 9 using trimethoxysilylpropyl methacrylate (γ–MPS) as a reactive silane coupling agent. FTIR and TGA analyses confirmed the presence of silane in the resultant structure and enhanced dispersion stability of modified particles was proved by a separation analyzer and also zeta potential analyses. In the second step, free radical polymerization of acrylic acid monomers in the presence of silanized nanoparticles was carried out and poly (acrylic acid) -grafted- silanized fumed silica were acquired. The flexural strength and fracture toughness of the adhesive containing 0.2 wt.% of the dual modified filler reached maximum of 70.4 MPa and 1.34 MPa m1/2, respectively, showing average improvements of 74% and 179%, respectively, in comparison with the adhesive without filler. Flexural modulus values did not significantly change with increasing the filler content except the adhesive containing 5 wt.% having the lowest flexural modulus. The highest microtensile bond strength was also observed at 0.2 wt.% filler content showing the average improvements of 197% as compared with the neat adhesive. Energy dispersive X-ray (EDX) mapping confirmed a homogenous and uniform distribution of the fillers in the adhesive matrix containing 0.2 wt.% and 0.5 wt.% of filler while incorporation of 5 wt.% led to large particle aggregates. SEM images of the fracture surface of the adhesive with different filler contents subjected to fracture toughness test showed rougher surface and longer crack path by increasing filler concentration. The adhesive containing 0.2 wt.% of filler perfectly penetrated into the dentin tubules proved by the SEM micrographs in microtensile bond strength test.

Comparative Evaluation of Microtensile Bond Strength of Three Restorative Materials

The present study aimed to compare the micro-tensile bond strength of new and conventional glass-ionomers and Z350 flowable composite resin to sound and caries-affected dentin. Eighty extracted third molars were selected. Standard Cl I cavities were prepared on occlusal surfaces. Forty teeth were assigned to the sound tooth group, and in the remaining 40 teeth, carious lesions were produced using a laboratory technique. Then each group (n=40) was subdivided into 5 groups (n=8) in terms of the restorative material used (EQUIA® Forte, Ketac Molar, encapsulated and hand-mixed GC Fuji II LC glass-ionomers and Z350 flowable composite resin). The cavities were restored. The highest micro-tensile bond strength was recorded with Z350 flowable composite resin in sound dentin (29.65), and the lowest was recorded with GC Fuji II LC (powder, liquid) in affected dentin (7.88). Significant differences were detected in the micro-tensile bond strength between the 5 restorative material groups. The composite resin bond strength was the maximum and was significantly different from all the other groups. The micro-tensile bond strength was affected by the type of dentin; in this context, in all the restorative groups, the bond strength in sound dentin was significantly higher than that in affected dentin. The most frequent failure mode was adhesive in the sound and affected dentin.

Comparison of the Microtensile Bond Strength of a Polyetherketoneketone (PEKK) Tooth Post Cemented with Various Surface Treatments and Various Resin Cements.

The aim of this in-vitro research was to evaluate the microtensile bond strength in the newly introduced PEKK tooth post with various surface treatments and resin cements. A fiberglass tooth post was included in order to compare it with PEKK as a possible post material. The microtensile bond strengths of the fiberglass post (FRC Postec Plus) and the PEKK post (Pekkton®) were tested using three kinds of self-adhesive resin cements (G-CEM LinkAce, Multilink Speed, and RelyX U200) and one self-etching resin cement (PANAVIA F2.0). The surface treatments of the fiberglass posts were processed according to the manufacturer’s recommendations (F1, application of 37% phosphoric acid etching gel and silanization). For the PEKK post groups, various surface treatments were performed like no surface treatment (P1), sandblasting (P2), silica-coating and silanization (P3), and sandblasting with a composite primer (P4). In the surface treatment, PEKK posts with silica coating and silane treatment (P3) showed a significantly higher microtensile bond strength (mean MPa: 18.09, p < 0.05). The highest microtensile bond strength was shown when the PEKK posts were treated with a silica coating and silane treatment and cemented with RelyX U200 (mean MPa: 22.22). The PEKK posts with surface treatments of silica-coating and silanization or sandblasting displayed superior microtensile bond strengths (mean MPa: 18.09 and 16.25, respectively) compared to the conventional fiberglass posts (mean MPa: 14.93, p < 0.05).

Epigallocatechin-3-gallate and Epigallocatechin-3-O-(3-O-methyl)-gallate Enhance the Bonding Stability of an Etch-and-Rinse Adhesive to Dentin.

This study evaluated epigallocatechin-3-gallate (EGCG) and epigallocatechin-3-O-(3-O-methyl)-gallate (EGCG-3Me) modified etch-and-rinse adhesives (Single Bond 2, SB 2) for their antibacterial effect and bonding stability to dentin. EGCG-3Me was isolated and purified with column chromatography and preparative high performance liquid chromatography. EGCG and EGCG-3Me were incorporated separately into the adhesive SB 2 at concentrations of 200, 400, and 600 µg/mL. The effect of cured adhesives on the growth of Streptococcus mutans (S. mutans) was determined with scanning electron microscopy and confocal laser scanning microscopy; the biofilm of bacteria was further quantified via optical density 600 values. The inhibition of EGCG and EGCG-3Me on dentin-originated collagen proteases activities was evaluated with a proteases fluorometric assay kit. The degree of conversion (DC) of the adhesives was tested with micro-Raman spectrum. The immediate and post-thermocycling (5000 cycles) bond strength was assessed through Microtensile Bond Strength (MTBS) test. Cured EGCG/EGCG-3Me modified adhesives inhibit the growth of S. mutans in a concentration-dependent manner. The immediate MTBS of SB 2 was not compromised by EGCG/EGCG-3Me modification. EGCG/EGCG-3Me modified adhesive had higher MTBS than SB 2 after thermocycling, showing no correlation with concentration. The DC of the adhesive system was affected depending on the concentration of EGCG/EGCG-3Me and the depth of the hybrid layer. EGCG/EGCG-3Me modified adhesives could inhibit S. mutans adhesion to dentin–resin interface, and maintain the bonding stability. The adhesive modified with 400 µg/mL EGCG-3Me showed antibacterial effect and enhanced bonding stability without affect the DC of adhesive.

Evaluating Resin-Dentin Bond by Microtensile Bond Strength Test: Effects of Various Resin Composites and Placement Techniques.

Objectives:This in vitro study evaluated the microtensile bond strength (MTBS) of a methacrylate-based compared to a silorane-based resin composite in Class I cavity using different placement techniques.Materials and Methods:Class I cavities with dimension of (4 mm long, 4 mm wide, 3 mm deep) were prepared in extracted sound human molars. The teeth were randomly divided into six groups. The first three groups were filled with Filtek P90 using three methods of insertion; bulk, incremental and snow-plow, and the remaining three groups were filled with Clearfil AP-X using the same three placement techniques. After 24 hours of storage in water at 37°C, the specimens were thermocycled to 1000 cycles. Specimens were prepared for MTBS testing by creating bonded beams obtained from the pulpal floor. Statistical analysis used: Statistical analyses of data were performed by two-way ANOVA/Tukey (α=.05).Results:The experiment showed significant differences between the two resin composites with regard to filling techniques (P<0.05). The MTBS was significantly higher in each of Filtek P90 subgroup compared to Clearfil AP-X ones (P<0.05). With respect to filling technique in both resin composites, bulk insertion showed the significantly lowest MTBS (P<0.05), while no significant difference was found between the outcome of incremental and snow-plow techniques (P>0.05).Conclusion:Silorane-based resin composite as opposed to methacrylate based resin composite and layering placements in contrast to bulk filling method had higher microtensile bond strength.

Effect of ascorbic acid on bond strength between the hydrogen peroxide-treated fiber posts and composite resin cores.

Aim:This study evaluated the effect of 10% ascorbic acid on the bond strength between fiber post and composite resin core after applying 24% hydrogen peroxide.Materials and Methods:Twenty-four hydrogen peroxide-treated fiber posts were divided into 4 groups (n = 6). Group 1 was the control group with no treatment. In groups 2-4, post surfaces were treated with 10% v ascorbic acid solution for 10, 30 and 60 minutes, respectively. Cores were built up using flowable composite resin. Two sticks were prepared from each specimen. Microtensile bond strength test was performed for each stick. Failure modes of sticks were evaluated under a stereomicroscope (×20). Surface morphologies of two fractured sticks from each group were assessed by SEM.Statistical analysis:Data were analyzed using one-way ANOVA and Tukey HSD tests (α = 0.05).Results:The highest microtensile bond strength was observed in Group 4 (20.55 ± 2.09) and the lowest in Group 1 (10.10 ± 0.55). There were significant differences in microtensile bond strength between all the groups (P < 0.05).Conclusion:It is concluded that ascorbic acid application increased the microtensile bond strength between the hydrogen peroxide treated fiber post and composite resin core. The increase is dependent on the duration of exposure to the antioxidant.

Effect of storage times and mechanical load cycling on dentin bond strength of conventional and self-adhesive resin luting cements

The lack of long-term bond stability between resin cements and dentin may compromise the success of indirect restorations. The purpose of this study was to evaluate the effects of long-term storage in artificial saliva and mechanical load cycling on the microtensile bond strength of conventional and self-adhesive resin cements to dentin. The occlusal dentin surfaces of 128 human molars were exposed and flattened. The teeth were assigned to 16 groups (n=8) according to resin cement and invitro aging strategy. Two self-adhesive resin cements (RelyX Unicem and Clearfil SA Cement) and 2 conventional cementing systems (RelyX ARC and Clearfil Esthetic Cement) were used. Resin cements were applied to prepolymerized indirect resin disks, which were bonded to the dentin surfaces and light polymerized. The control groups were represented by immediate microtensile bond strength (24 hours) and aging methods were performed with mechanical load cycling or storage in artificial saliva (1 year and 2 years). Bonded beams were tested in tension until failure. Data (MPa) were analyzed by Proc Mixed for repeated measures and the Tukey-Kramer test (α=.05). The self-adhesive resin cements exhibited higher microtensile bond strength than conventional cementing systems for all conditions studied. The microtensile bond strength of RelyX ARC and self-adhesive resin cements did not decrease after storage in artificial saliva and mechanical load cycling. The Clearfil Esthetic Cement showed the lowest microtensile bond strength and a significant reduction after 2 years of storage in artificial saliva. The storage times and mechanical load cycling did not affect the microtensile bond strength of self-adhesives and RelyX ARC resin cements. The highest microtensile bond strength was obtained for self-adhesive resin cements, with no significant difference between them.

Effect of Etching Time on Resin-Primary Dentin Adhesion and Degradation of Interfaces

The purpose of this research was to evaluate the resin–dentin bond degradation in primary teeth after reducing the etching time. The dentin surfaces were bonded with: an etch and rinse adhesive (single bond-SB); a two step self-etching adhesive (Clearfil self etching bond-CSEB); and a one-step self-etching adhesive (one up bond F-OUB). For half the specimens, the recommended etching time was used (the manufacturer’s instructions); for the other half the etching time was reduced by 50%. The bonded teeth were divided according to different challenging procedures: (a) 24 h storage in distilled water and sectioned into beams (1.0 mm2); (b) immersion of the bonded beams in 10% NaOCl aqueous solution for 5 h; (c) load cycled (5000 cycles, 90 N) and then sectioned into beams. The micro-tensile bond strength (MTBS) was measured and fractographic analysis performed. The data were statistically analyzed using an analysis of variance (ANOVA) technique, together with multiple comparisons tests. The results showed that the OUB produced the lowest MTBS values, regardless of the challenging procedure. After NaOCl immersion, the MTBS decreased in all groups, with the Clearfil self etching bond (immersed for half the time) attained the highest MTBS. Following the instructions for each of the adhesive systems, after load cycling, no differences in MTBS were observed in the samples after 24 h. However when the etching time was shortened, a decrease in MTBS were observed for all groups. In conclusion, shortening the etching/conditioning time caused a significant change to the bond strength which was material dependent. The OUB produced the lowest bond strengths, regardless of other variables; and a reduced conditioning time resulted in an increased bond strength for CSEB adhesive.

Effect of various disinfection methods on bonding strength of glassfibre post to root canal dentine

Disinfection is a critical step in the treatment of a root canal before sealing it with post. This study was to evaluate the effects of various root canal disinfection methods on the bond strength of a glassfibre post to root canal dentine. Forty-eight premolars were studied. The root canals were divided into six groups. Glassfibre posts were cemented with a dual cure composite resin cement following disinfection by using Waterlase laser, Key laser, bioactive glass granules, Tubulicid Plus, NaCl solution (control) and NaOCl solution. Specimens were stored for 8 months. The root part of the tooth was cut and prepared into an hourglass shaped specimen for microtensile bond test. Statistical analysis was performed. Failure types were evaluated and SEM images were taken. The bond strength of fibre posts was significantly affected by the type of disinfection. The highest microtensile bond strength was observed in specimens disinfected by using bioactive glass granules, whereas the lowest bond strength values were recorded with NaOCl irrigation. The bond strength of glassfibre post to root canal dentine was affected by disinfection procedure.

Microtensile bond strength of etch and rinse versus self-etch adhesive systems

The aim of this study was to compare the microtensile bond strength of the etch and rinse adhesive versus one-component or two-component self-etch adhesives. Twelve intact human molar teeth were cleaned and the occlusal enamel of the teeth was removed. The exposed dentin surfaces were polished and rinsed, and the adhesives were applied. A microhybride composite resin was applied to form specimens of 4 mm height and 6 mm diameter. The specimens were sectioned perpendicular to the adhesive interface to produce dentin–resin composite sticks, with an adhesive area of approximately 1.4 mm 2. The sticks were subjected to tensile loading until failure occurred. The debonded areas were examined with a scanning electron microscope to determine the site of failure. The results showed that the microtensile bond strength of the etch and rinse adhesive was higher than that of one-component or two-component self-etch adhesives. The scanning electron microscope examination of the dentin surfaces revealed adhesive and mixed modes of failure. The adhesive mode of failure occurred at the adhesive/dentin interface, while the mixed mode of failure occurred partially in the composite and partially at the adhesive/dentin interface. It was concluded that the etch and rinse adhesive had higher microtensile bond strength when compared to that of the self-etch adhesives.

The influence of ceramic surface treatments on the microtensile bond strength of resin cements to Y-TZP ceramic

The effects of surface conditioning methods on the microtensile bond strength of Y-TZP ceramic were studied based on airborne particle abrasion and resin cements. Eight square-shaped (ϕ12 mm×5 mm high) Y-TZP ceramic were studied blocks (LAVA™, 3M ESPE, USA) and flat occlusal dentin blocks were fabricated, pre-treated(airborne abrasion with 125μm Al2O3 particles, tribochemical silica coating with 110 μm Al2O3 particles modified by silica oxide), and bonded to each other using resin cements(Panavia F 2.0, RelyX Unicem). Thereafter the trilayer specimens were cut into microbar specimens with a bonding area of approximately 1.0±0.1 mm2 and then microtensile bond strength tests were performed. The Y-TZP ceramic following airborne particle abrasion with 125μm Al2O3 and silicoating, the surface roughness of Y-TZP and its surface silica content were confirmed to increase. Overall, the Y-TZP ceramic surface treatment with a tribochemical silica coating showed the highest microtensile bond strength of the phosphate monomerbased resin cement to Y-TZP ceramic(mean MPa= 18.11±0.27(Panavia F 2.0), 17.45±0.39(RelyX Unicem). In cases in which a silica coating was applied, there was no significant difference in the bonding strength depending on resin cements (P>0.05).

Microtensile Bond Strengths of Composite Cores to Pulpal Floor Dentin with Resin Coating

The purpose of this study was to evaluate the effect of resin coating on the microtensile bond strength (MTBS) of indirect composite cores to pulpal floor dentin. Thirty extracted human molars with root canal fillings were used. After post space preparation, dentin surface was coated with either Clearfil SE Bond (SE) or SE with Clearfil Flow FX (SE+FX) for the resin-coated groups, while dentin was treated with ED Primer II (ED) for the non-coated group. Indirect composite cores were cemented with either Panavia F2.0 (PA) or Clearfil DC Core Automix (DC). After 24-hour storage, MTBSs were measured at a crosshead speed of 1 mm/min. Two-way ANOVA indicated that the MTBSs of resin-coated groups were significantly higher than those of the non-coated groups. In particular, the SE+FX/DC group exhibited the highest MTBS. It was thus concluded that resin coating enhanced the dentin bond strength of indirect composite cores to pulpal floor dentin.

Post silanization improves bond strength of translucent posts to flowable composite resins

The aim of the study is to evaluate the effect of post silanization on the microtensile bond strength (MTBS) of translucent fiber posts to seven flowable composite resins used as core material. Seventy fiber posts were employed. In half of the posts, silanization was performed with Monobond-S. A cylindrical plastic matrix was placed around the post and filled with different resins: UniFil Flow Experimental, UniFil Low Flow Plus Experimental, Venus Flow, Revolution Formula 2, Point 4 Flowable, X-Flow, and Wave mv. Five posts were bonded per group. After polymerization, two longitudinal cuts were made on two opposite sides of the post at its outermost periphery. Then, each specimen was serially sectioned, obtaining 30-35 beams with 1-mm(2) cross-sectional area. Each beam was tested in tension in an Instron machine at 0.5 mm/min. ANOVA and Student Newman Keuls tests were performed. The different resin composite materials and the post silanization procedure had a significant effect on MTBS. The application of a silane coupling agent increased MTBS of flowable composite resins to translucent posts. X-flow and Point 4 attained the highest MTBS regardless of the silane treatment.

Enhancement of Adhesion between Resin Coating Materials and Resin Cements

Resin coating technique is a unique method that improves the dentin bond strength of resin cements in indirect restorations. However, the weak link of a specimen bonded using the resin coating technique was reported to be the bonded interface between the resin coating material and resin cement. The purpose of this study, therefore, was to enhance the bonding performance between a resin coating material and a resin cement. Two light-cured flowable composites, Protect Liner F and Clearfil Flow FX, were used as coating materials, and two dual-cure composite materials, Panavia F 2.0 and Clearfil DC Core Automix, were used as resin cements. The ultimate tensile strength of each material and the microtensile bond strengths of the bonded specimens of resin coating material and resin cement were measured using a crosshead speed of 1.0 mm/min. Three-way ANOVA (p=0.05) revealed that the highest microtensile bond strength was obtained using a combination of Clearfil Flow FX and Clearfil DC Core Automix, and when the surface of the coating material was treated with ED Primer II. It was strongly suggested that materials with a higher ultimate tensile strength, when used in both resin coating and cementation, could enhance the bond strength between the two.

Association between microtensile bond strength and microleakage at the resin based composite/dentin interface - an in vitro study

Background and objective : True adhesion has been the 'holy grail' of restorative dentistry. Iftrue adhesion of restorative materials to tooth structure is to be achieved, optimal retention must be obtained and microleakage must be prevented. This study was conducted to evaluate the correlation between microtensile bond strength and microleakage using two different adhesives systems, which differed in their mode of adhesion. Method : Box type Class I occlusal cavities were prepared on twenty molar teeth. The teeth were assigned to two groups Group I (Gluma Comfort Bond and Charisma), Group 11 (i-Bond and Charisma), each comprising of ten teeth. Restored teeth were subjected to thermocycling, followed by dye immersion and sectioning. Microleakage evaluation for the extreme end slices was done using dye immersion technique and then viewed under stereomicroscope. Microtensile bond strength testing of the middle two slices was done using an Universal Testing Machine (Instron). Results : Statistically, Group I showed higher microtensile bond strength and lower microleakage value when compared to Group 11. A highly significant negative correlation was found between microtensile bond strength and microleakage. Interpretation and conclusion · Smear layer removing adhesive system exhibited higher bond strength and less leakage than smear layer dissolving adhesive system. An inverse relationship exits between microtensile bond strength and microleakage.