Difference In Bond Strength Values Research Articles

Shelf life effects on the bond strength and microhardness of self-adhesive resin cements.

Among the main advantages of self-adhesive resin cements comprise good aesthetics, strong restoration-tooth bond and biocompatibility. However, some disadvantages, such as high viscosity level, color limitation and short shelf life should be mentioned. Thus, the aim of the current study was to assess bond strength between fiberglass post and root dentin in teeth subjected to self-adhesive resin cements with expired shelf life and hardness. Sixty (60) single-rooted human teeth were sectioned and divided into 2 groups of different cements: U200 3M and MaxCem Elite Kerr. Each group was divided into 3 subgroups, based on self-adhesive resin cements' shelf life, namely: Within the use-time recommended by the manufacturer or no expiration date; 6 months after opening the aluminum blister; 12 months after opening the aluminum blister. Bond strength was measured through push-out test conducted in universal testing machine; fracture pattern was analyzed, and microhardness was investigated through Knoop test, based on hardness readings. Data were subjected to Shapiro-Wilk normality test; nonparametric test was applied to hardness data, whereas parametric test was applied to bond strength data. Hardness data were subjected to Kruskal-Wallis test, whereas bond strength data were subjected to analysis of variance, which was followed by Tukey test; both tests were conducted at 5% significance level (α = 0.05). There was no statistically significant difference in knoop hardness values recorded for the material / time / root thirds combination (p=0.483). There was no statistically significant difference in bond strength values recorded for the Material / Time / Thirds combination (p=0.237). It was possible concluding that shelf life did not influence material's hardness and bond strength. Key words:Dental cements, Resin Cements, Shelf Life of Products.

How the translucency of direct anatomic fiber posts affects the bond strength and microhardness of a self-adhesive luting agent in flared roots.

To evaluate the influence of the composite resin translucency used in direct anatomic fiber posts on the bond strength (BS) and microhardness (VHN) of a luting agent into flared roots. The root canals of 70 single-rooted premolars were endodontically treated and prepared to simulate an oversized root canal. Prior to post cementation, composite resins with varying translucency (high translucent, HT; medium translucent, MT; high opacity, HO) were placed around the fiber posts to create anatomic fiber posts. The attenuation profile (%) of light passing either through the post or through the anatomic posts (n = 8) was obtained prior to the cementing procedures. A positive control group (PC) in which a prefabricated fiber post (PFP) with the diameter compatible with the root canal was cemented and a poorly adapted fiber post (negative control group, NC) were also evaluated. For both tests, the data were subjected to 2-way ANOVA and Bonferroni tests (α = 0.05). A more severe light attenuation through the post at the cervical (P < .001) and medium (P < 0.001) thirds was noted when less translucent composite resin surrounded the anatomic post. HO groups showed lower BS (P = .009) and VHN (P < .001) values than the other groups, regardless of root third. No significant difference in BS values was noted between PC and HT groups. The use of a more translucent composite resin in anatomic fiber posts increased the microhardness and bond strength of a dual polymerization self-adhesive RLA compared to the use of MT and HO composite. A well-adapted PFP showed the highest adhesive and mechanical behavior. Clinicians should choose more translucent composite resins to create direct anatomic fiber posts to be cemented in flared root canals. That choice may allow improved mechanical properties of self-adhesive RLA and higher bond strength to the root canal as a consequence.

Bond Strength of Self-Adhesive Flowable Composites and Glass Ionomer Cements to Primary Teeth: A Systematic Review and Meta-Analysis of In Vitro Studies.

Background: Conventional composites are largely used in pediatric restorative dentistry and demonstrate successful clinical outcomes. However, the need for simplification of operative steps in young or uncooperative children demands reliable alternatives. Therefore, the aim of the present systematic review and meta-analysis was to evaluate the in vitro bond strength of glass ionomer cements (GICs) and self-adhesive flowable composites (SFCs) on deciduous teeth. Methods: A comprehensive literature search according to the PRISMA checklist was manually and electronically performed by two independent reviewers through the following databases: MEDLINE/PubMed, Google Scholar, Scopus, and Embase, to include in vitro studies comparing GICs and SFCs bond strength values of restorations on primary teeth. In addition, three groups of meta-analyses were conducted using random-effects models. Results: Three articles meeting the inclusion criteria were selected and subjected to both qualitative and quantitative assessment. No statistically significant difference was found between SFC versus GIC; however, both groups significantly differed with conventional flowable composites (CFs). Conclusions: Despite the absence of significant difference in bond strength values, SFCs may be considered a valid alternative to GICs in the restoration of deciduous teeth, although CFs proved better in vitro performances.

Effect of dental acid etchant-mediated photodynamic therapy on bacterial reduction and microshear bond strength of composite to dentin - An in vitro study.

Objective:The objective of this study was to assess the effect of dental acid etchant (DAE)-mediated photodynamic therapy on bacterial reduction and microshear bond strength of composite to dentin.Materials and Methods:Eighty permanent third molars after sample preparation were exposed to a cariogenic challenge with Streptococcus mutans. After incubation, specimens were randomly divided into four groups (n = 20): Group I – DAE, Group II – low-level laser (LLL), Group III – diode laser + methylene blue (MB + L), and Group IV – diode laser + DAE (DAE + L). Half of the specimens from each group were selected for bacterial reduction assessment and the other half for microshear bond strength. All the samples for assessment of bacterial reduction (before and after intervention) were seeded onto the surface of mitis-salivarius-bacitracin medium. After incubation, the viable bacterial count was determined in colony-forming unit/mL. For microshear bond strength assessment, samples were subjected to various treatment modalities and then bonding and debonding procedure was performed for blocks of composite and values were recorded.Results:Significant reductions in S. mutans were observed in all the groups – Group I (DAE) 68.50%, Group II (LLL) 55.90%, Group III (MB + L) 88.60%, and Group IV (DAE + L) 87% with comparable bacterial reduction between Group III (MB + L) and Group IV (DAE + L). Furthermore, a significant difference in bond strength values was seen in Group III (MB + L) 10.99 MPa and Group IV (DAE + L) 17.99 MPa whereas an insignificant difference was found between Group I (DAE) 20.74 MPa, Group II (LLL) 18.27 MPa, and Group IV (DAE + L).Conclusion:DAE caused a comparable reduction in bacterial count to MB-assisted PDT and also there was no adverse effect on bond strength values. PDT can be performed while acid etchant containing MB dye is being applied in the cavity, thus reducing operative time and enhancing cavity disinfection.

Influence of curcumin photosensitizer in photodynamic therapy on the mechanical properties and push-out bond strength of glass-fiber posts to intraradicular dentin.

The effects of using curcumin as photosensitizer on the mechanical properties of intraradicular dentin and on the bond strength of glass-fiber posts are unknown. Thus, this in vitro study evaluated the influence of using curcumin as photosensitizer during photodynamic therapy on the Martens hardness, elastic modulus, and bond strength of glass-fiber posts luted to intraradicular dentin, in different tooth root thirds. Eighty bovine teeth were divided into 5 groups according to the concentration of curcumin applied, with or without blue LED light activation: Control-deionized water; Curcumin 500 mg/L; Curcumin 500 mg/L + blue LED; Curcumin 1000 mg/L; and Curcumin 1000 mg/L + blue LED. Mechanical properties were measured in different thirds of the radicular dentin using an ultramicrohardness tester (n = 8). A universal testing machine was used to evaluate the push-out bond strength (n = 8). Mechanical properties were compared across groups with the Kruskal-Wallis test, and across regions with the Friedman test. Bond strength data were subjected to ANOVA, followed by Tukey's test (α = 0.05). Scanning electron microscopy was used to analyze the failure mode of the specimens. The use of curcumin photosensitizer, with or without blue LED light, improved mechanical properties compared to those of the control group (P < 0.05), and promote no statistically significant difference in bond strength values (P > 0.05). Overall, there was no difference among the intraradicular thirds for Martens hardness and push-out bond strength values (P > 0.05). Curcumin photosensitizer, with or without photodynamic therapy, changed the mechanical properties of intraradicular dentin; however, the Martens hardness and bond strength values did not differ with the depth of the dentin.

Micro-shear bond strength of universal adhesives used for amalgam repair with or without Alloy Primer.

Aim:The aim of this study was to investigate the adhesive performance of three different universal adhesives to repair aged amalgam by composite resins with or without Alloy Primer.Materials and Methods:Sixty amalgam samples were prepared, aged, and randomly divided into 12 main groups according to adhesive procedures used. Composite buildups were placed on amalgam surfaces. After micro-shear bonding test, the fracture surfaces were examined under the scanning electron microscopy statistical analysis was performed using two-way analysis of variance and Tukey's post hoc tests.Results:Without use of Alloy Primer, all of the universal adhesives provided similar bond strength values with conventional adhesives (P > 0.05); however, an Alloy Primer significantly increased the bond strength values of universal adhesives (P < 0.05). No significant difference in bond strength values was noted for conventional adhesives with or without Alloy Primer (P > 0.05) except for Clearfil SE Bond (P < 0.05).Conclusions:Within the limitations of this study, it can be concluded; using Alloy Primer before universal adhesives increased the bond strength significantly.

Shear bond strength of one-step self-etch adhesives to dentin: Evaluation of NaOCl pretreatment.

BackgroundThe aim of this study was to evaluate the influence of dentin pretreatment with NaOCl on shear bond strength of four one-step self-etch adhesives with different pH values.Material and MethodsBovine permanent incisors were used. Four one-step self-etch adhesives were tested: Adper™ Easy Bond, Futurabond NR, G-aenial Bond, Clearfil S3 Bond. One two-step self-etch adhesive (Clearfil SE Bond) was used as control. Group 1- no pretreatment; group 2- pretratment with 5,25 % NaOCl; group 3- pretreatment with 37 % H3PO4 etching and 5,25 % NaOCl. A hybrid composite resin was inserted into the dentin surface. The specimens were tested in a universal testing machine. The examiners evaluated the fractured surfaces in optical microscope to determine failure modes, quantified with adhesive remnant index (ARI).ResultsDentin pretreatment variably influenced bond strength values of the different adhesive systems. When no dentin pretreatment was applied, no significant differences were found (P >.05) among four adhesives tested. No significant differences were recorded when comparing NaOCl pretreatment with H3PO4 + NaOCl pretreatment for all adhesive tested (P >.05) except Clearfil S3 Bond that showed higher shear bond strength values when H3PO4 was applied. Frequencies of ARI scores were calculated.ConclusionsThe influence of dentin pretreatment with NaOCl depends on the composition of each adhesive system used. There was no difference in bond strength values among self-etch adhesives with different pH values. Key words:Dentin, pretreatment, self-etch adhesives.

BONDING ABILITY OF DIFFERENT LINERS TO BULK-FILL RESIN COMPOSITE USING SILANE-CONTAINING ADHESIVE

Aims: To compare and evaluate the bonding ability of bulk-fill resin composite (RC) to four different liners: Biodentine (BD), TheraCal (TLC) - a novel resin-modified calcium silicate cement, resin-modified glass ionomer cement (RMGIC) and conventional glass ionomer cement (GIC) using a universal silane-containing adhesive and characterizing their failure modes.Materials and Methods: Forty extracted intact human premolars with occlusal cavity (4-mm diameter and 2-mm height) were mounted in acrylic blocks and divided into four groups of (n=10 samples) each based on the liner used as group I; (BD), group II; (TLC), group III; (RMGIC) and Group IV; (GIC). Bulk-fill composite buildup of 3 mm diameter and 5 mm height was then bonded to each sample using universal adhesive. Shear bond strength (SBS) analysis was performed using materials testing machine at a cross-head speed of 0.5 mm/min. Statistical Analysis: Statistical analysis was performed with one-way analysis of variance (ANOVA) and Tukey’s post hoc test for numerical data while chi square test for categorical one. Results: One-way analysis with ANOVA revealed significant difference in bond strength values between the different groups (p<0.001). The observed modes of failure were predominantly cohesive in Biodentine, TheraCal and GIC groups while RMGIC showed majority of mixed and minority adhesive failures.Conclusions: Biodentine demonstrated lower bond strength values when immediately bonded to bulk-fill resin composite compared with RMGIC, TheraCal and GIC groups

SHEAR BOND STRENGTH OF VISCOUS VERSUS RESIN MODIFIED GLASS IONOMERS TO DENTIN CONDITIONED WITH DIFFERENT PROTOCOLS

Objectives: This study was conducted to examine the effect of conditioning protocols on shear bond strength of viscous glass-ionomer cement (GIC) Versus resin-modified glass-ionomer cement (RMGIC) to dentin. Materials and methods: Forty caries free permanent molars were used. They were sectioned mesiodistally into two halves to obtain 80 specimens that were divided into eight groups (n=10) according to the conditioning protocol. In Group 1 and 2: Dentin was preconditioned with 10% polyacrylic acid either for 10 or 20 seconds and bonded to viscous glass ionomer (Fuji IX GP Extra) using a specially constructed mold (2 mm diameter X 3mm height). In Group 3 and 4: Preconditioning was followed as in group 1 and 2 but RMGI (Fuji II LC) was used. However, in group 5 and 6, dentin was preconditioned with 37% phosphoric acid either for 10 or 20 seconds followed by packing of viscous GI. Group 7 and 8: Preconditioning was done as previous followed by application of RMGI. The specimens were placed in a universal testing machine (Model 3345, Instron Corp., Canton, Mass., USA) with a cross head speed 0.5 mm/min and subsequently tested for shear bond strength SBS (MPa). Statistical analysis was done by using ANOVA and independent t test. Results: SBS values revealed higher bond strength values for RMGI in comparison to viscous GI. Polyacrylic acid groups exhibited higher values than those of phosphoric acid. There was no significant difference in bond strength values of specimens conditioned by the two conditioners for either 10 or 20 seconds(P ≤ 0.05). Conclusions: RMGI experienced high SBS values to dentin. The effect of acid used for dentin conditioning prior to viscous and RMGI can not be overemphasized.

Influence of chlorhexidine in cavities prepared with ultrasonic or diamond tips on microtensile bond strength

This study evaluated the effect of chlorhexidine (CLX) in cavities prepared with either ultrasound-mounted CVDentUS diamond tips or conventional diamond burs on dentin bond strength after 24 h and 180 days. Forty-eight dentin surfaces from sound third molars were flattened and divided into four groups (n = 12), according to the type of cavity preparation (CVDentUS ultrasound tip or conventional diamond) and with or without 2% CLX (Consepsis) treatment. After application of the adhesive system (Clearfil SE Bond), microhybrid composite resin blocks (Charisma) were made on the dentin surface in increments. After 24 h, the specimens were sectioned into stick-shaped samples with an adhesive interface of approximately 1 mm2. From each tooth, half of the sticks were evaluated after 24 h of storage in distilled water and the other half after 180 days, using a universal testing machine. Three-way analysis of variance showed no significant triple interactions (p = 0.722) or double interactions between factors. Higher bond strength values were observed with the use of ultrasonic tips (p = 0.019), irrespective of whether or not CLX was applied in either time period. No difference in bond strength values was observed in terms of CLX application (p = 0.581). No significant difference in bond strength values was shown after storage for 24 h or 180 days (p = 0.302). In conclusion, the ultrasonic tips promoted greater bond strength to dentin, irrespective of whether or not CLX was applied, and storage time.

TiF4 improves microtensile bond strength to dentin when using an adhesive system regardless of primer/bond application timing and method.

This study evaluated the bond strength of a two-step conventional adhesive system to dentin pretreated with 2.5 % titanium tetrafluoride (TiF(4)) according to application timing (before or after acid conditioning) and primer/adhesive application method (active or passive). Dentin surfaces were randomly treated with different adhesive procedures (n = 6): etching with phosphoric acid (PA) + primer/adhesive (Adper Single Bond 2/3M ESPE) actively applied; PA + primer/adhesive passively applied; TiF(4) before PA + primer/adhesive actively applied; TiF(4) before PA + primer/adhesive passively applied; TiF(4) after PA + primer/adhesive actively applied; and TiF(4) after PA + primer/adhesive passively applied. A composite block was built onto the tooth, which was sectioned into sticks (adhesive area of approximately 1 mm(2)). Microtensile bond strength tests and the failure mode were determined. Two-way ANOVA revealed no significant interaction between TiF(4) application timing and primer/adhesive application method (p = 0.184). The use of TiF(4), before or after PA significantly increased bond strength values (p < 0.001). There was no significant difference in bond strength values when using TiF4 before or after PA. The primer/adhesive application method had no influence on bond strength, regardless of whether TiF(4) was used (p = 0.906). Failure mode was predominantly adhesive. The use of TiF(4) promoted higher immediate bond strength to dentin. The conventional adhesive system may be applied either actively or passively, regardless of TiF(4) application timing. Pretreatment with TiF(4) increased bond strength in a conventional two-step adhesive system to dentin, regardless of the primer/adhesive application method and the timing of dentin pretreatment.

Effect of thermal cycling and low pressure sandblasting on the bond strength of a self-adhesive cement to Y-TZP zirconia

The aim of this investigation was to assess the influence of several surface treatments on the shear bond strength (SBS) of a self-adhesive resin cement containing 10-methacryloxydecyl-dihydrogenphosphate monomer to densely sintered zirconia ceramic, before and after thermal cycles. Hundred densely sintered zirconia cylinders were divided into five groups (n = 20). Each of them received a different surface treatment: (1) control [No_T], with the zirconia surface unconditioned, (2) low pressure air abrasion [Sand_S], (50 μm, 1 bar), (3) standardized air abrasion [Sand_H], (50 μm, 2.8 bar), (4) standardized Rocatec™ Plus (silica-coated alumina oxide) air abrasion (2.8 bar) and silanization [Roc_H], (5) low pressure Rocatec™ Plus (silica-coated alumina oxide) air abrasion (1 bar) and silanization [Roc_S]. Five more surface-treated specimens were addressed to scanning electron microscope for qualitative observations. After specimen fabrication, subgroups of 10 bonded samples were stored in water either for 24 h (T1) or subjected to 5000 thermal cycles (T2); SBSs were determined with a universal testing machine at a crosshead speed of 1 mm/min. At T1, mean SBSs (MPa) obtained for the examined groups were: [Sand_H] 16.24 ± 2.95; [Sand_S] 16.01 ± 2.68; [Roc_H] 17.17 ± 1.64; [Roc_S] 15.92 ± 1.99. All surface treatments positively affected (p < 0.05) the initial self-adhesive cement adhesion to zirconia with respect to No_T (13.29 MPa). Artificial aging decreased the bond strength in all test groups significantly, but no spontaneous debonding was observed in [No_T]: at T2, SBS values ranged from 7.76 ± 2.37 (No_T) to 8.89 ± 1.74 (Sand_S), with no statistically significant difference between groups (p = 0.5293). Both air abrasion with alumina oxide and Rocatec™ universal bonding system, used with hard or low air pressure, produced comparable effects on cement–zirconia interface before and after thermal cycles. After artificial aging, minimal differences in bond strength values between sandblasted and control groups were not of statistical significance.

Influence of cleansing agents on enamel and dentin bond strength to a one-step adhesive system

Objective: The aim of this study was to detect the influence of application mode of cleansing agents, on enamel and dentin during the adhesion process of a one-step adhesive system.Materials and Methods: 24 human molars were sectioned into halves along the long axis for enamel and dentin tests. The cleansing agents used were hydrogen peroxide, anionic detergent, and antiseptic solution. In the experiment, these agents were applied with and without friction on enamel and dentin surfaces. A one-step adhesive system (Clearfil S3 Bond) was applied on dental surface and composite resin cylinders were built using Tygon tubing molds. After 24 h, ?SBS test (1 mm/ min) and fracture analysis were performed. Results: There was no statistically significant difference in bond strength values regarding the application mode of cleansing agents for enamel and dentin (p?0,05).Conclusions: Regarding bond strength, application mode of the cleansing agents used in this study presented the same behavior.

Effect of different mechanical and chemical surface treatments on the repaired bond strength of an indirect composite resin

This study compared the effects of two mechanical surface preparation techniques, air abrasion and Nd:YAG laser, with the use of two adhesive systems, self-etch and etch and rinse, on the repair bond strengths of an indirect composite resin. One hundred fifty cylindrical samples of an indirect composite resin were prepared and randomly divided into six groups (n = 25). In groups 1-3, the composite resin surfaces were respectively prepared as follows: no roughening, roughening by air abrasion, and roughening by Nd:YAG laser, followed by application of an etch-and-rinse adhesive. In groups 4-6, the preparation techniques were respectively the same as those in groups 1-3, followed by application of a self-etch adhesive. Subsequently, a direct composite resin was added and repair bond strengths were measured. Data were analyzed with two-way ANOVA and post hoc Tukey's test. Mean bond strength value was significant based on the preparation technique (P < 0.001), i.e., in air abrasion and Nd:YAG laser groups, bond strengths were significantly higher compared to no-preparation groups (P < 0.0005). There were significant differences in bond strength values between air abrasion and Nd:YAG laser groups, with significantly higher values in air abrasion groups (P < 0.0005). However, there were no significant differences in bond strength values between the adhesive systems. Furthermore, the cumulative effects of the adhesive system and the surface preparation technique were not significant. Surface preparation of the indirect composite resin with air abrasion and Nd:YAG laser resulted in a significant increase in the repair bond strength, with air abrasion being more effective. There were no significant differences in bond strength between the two adhesives.

Bond strength of one-step self-etch adhesives and their predecessors to ground versus unground enamel

The aim of this study was to compare the shear bond strength of several self-etch adhesives to their two-step predecessors to ground and unground enamel. Seventy-five extracted, non-carious human third molar teeth were selected for this study. The buccal surfaces of each tooth were mechanically ground to obtain flat enamel surfaces (ground enamel), while the lingual surfaces were left intact (unground enamel). The teeth were randomly divided into five groups according to the adhesive systems (n=15): one-step self-etch adhesive - Clearfil S3 Bond, its two-step predecessor - Clearfil SE Bond, one-step self-etch adhesive - AdheSE One, and its two-step predecessor - AdheSE, and a two-step etch-and-rinse adhesive - Adper Single Bond 2(control). After application of the adhesives to the buccal and lingual enamel surfaces of each tooth, a cylindrical capsule filled with a hybrid composite resin (TPH) was seated against the surfaces. The specimens were stored in distilled water at 37°C for 24 hours, followed by thermocy-cling (5°C-55°C/500 cycles). They were subjected to shear bond strength test in a universal testing machine at a crosshead speed of 1.0 mm/minute. The data were compared using a two-way ANOVA, followed by Bonferroni test at P<.05. All adhesives exhibited statistically similar bond strengths to ground and unground enamel except for the etch-and-rinse adhesive that showed significantly higher bond strengths than the self-etch adhesives (P<.05). No significant differences in bond strength values were observed between ground and unground enamel for any of the adhesives tested (P=.17). Similar bond strengths to ground and unground enamel were achieved with one-step self-etch adhesives and their predecessors. Enamel preparation did not influence the bonding performance of the adhesives tested.

Effect of two different dentin desensitizers on shear bond strength of two different bonding agents to dentin: An in vitro study

The objective of the study was to compare the effect of two different desensitizers on shear bond strength of two different fifth-generation single-bottle adhesive agents on dentin surface. Sixty human premolars were taken and divided into six groups of 10 samples each. The first two groups were the control groups and were not pretreated with any desensitizer; the remaining four groups were the experimental groups and were pretreated with either Denshield™ or Sensodent-K™ desensitizer. The specimens in each group were subjected to acid etching, application of adhesive (Single Bond or Prime and Bond NT), and application of hybrid composite resin (Z-100) according to the standard protocol. The specimens were subjected to shear bond strength testing, using a Lloyds universal testing machine (EZ20), followed by stereomicroscopic evaluation of the fracture mode at the debonded interface. Statistically significant difference existed between the two bonding agents in the control groups (group 1 and 2), with Prime and Bond NT showing higher bond strength than Single Bond. No statistically significant difference existed between either control or pretreated with any desensitizer when either of the adhesive systems was used. Prime and Bond NT showed statistically higher bond strength value when teeth were pretreated with Sensodent-K™ (groups 5 and 6). No statistically significant difference in bond strength values were observed between the bonding agents when pretreated with Denshield™ desensitizer.

A comparative study to evaluate the effect of calcium sodium phosphosilicate desensitizer on the shear bond strength of two different total etch adhesives

Introduction The objective of the study was to compare the effect of calcium sodium phosphosilicate desensitizers on shear bond strength of two different fifth generation single bottle adhesive agents on dentin surface. Materials and Method Eighty human premolars were taken and divided into four groups of 20 samples each. The first two groups were control groups not pretreated with any desensitizers the remaining two groups are experimental groups pretreated with calcium sodium phosphosilicate desensitizer. The specimens in each group were subjected to acid etching, application of adhesive (Excite F or XP Bond), and hybrid composite resin (Z-100) under standard protocol. The specimen were subjected to shear bond strength using Lloyds universal testing machine (EZ 20) followed by stereomicroscopic evaluation of the fracture mode at debonded interface. Results Statistically significant difference existed between the two bonding agents of control groups (groups 1 and 2), i.e. XP Bond showed higher bond strength than Excite F. No statistically significant difference existed between either control or pretreated with desensitizer when either of the adhesive systems was used. No statistically significant difference in bond strength values were observed between the bonding agents when pretreated with calcium sodium phosphosilicate desensitizer.

Influence of blood contamination on bond strength of a self-etching adhesive to dental tissues

The aim of this study was to detect the influence of (1) storage period of heparinized blood, (2) type of blood and presence of contaminant, (3) application mode of cleansing agents, and (4) efficacy of cleansing agents on contaminated enamel and dentin during the adhesion process of a one-step adhesive system. One hundred four human molars were sectioned into halves along the long axis for enamel and dentin tests. Heparinized and fresh blood were obtained from the same donor, applied and dried to maintain a layer of dry blood on the top of samples. The cleansing agents used were hydrogen peroxide, anionic detergent, and antiseptic solution. A one-step adhesive system (Clearfil S3 Bond) was applied on the dental surface, and composite resin cylinders were built up using Tygon tubing molds. After 24 h, the μSBS test (1 mm/min) and fracture analysis were performed. There was no statistically significant difference in bond strength values regarding the storage period of heparinized blood and the types of blood. Groups without contamination presented higher bond strengths than contaminated groups. The application mode of the cleansing agents had no influence on bond strength results. There was no statistically significant difference among cleansing agents and they were as effective as a water stream in counteracting the effect of blood contamination. Heparinized blood can be used as a contaminant for up to one week, and it is a reliable procedure to standardize the contaminant. The cleansing agents can be used without friction. A water stream is sufficient to remove blood contamination from dental tissues, before the application of a one-step adhesive system.

Microtensile bond strength of three simplified adhesive systems to caries-affected dentin

The purpose of the study was to determine the microtensile bond strength of three different simplified adhesive systems to caries-affected dentin. Fifteen extracted human molars with primary carious lesions were ground flat until dentin was exposed. Soft caries-infected dentin was excavated with the help of caries detector dye. On the remaining hard dentin, a standardized smear layer was created by polishing with 600-grit SiC paper. Teeth were divided into three groups and treated with one of the three tested adhesives: Adper Scotchbond 1 XT (3M ESPE), a 2-step etch-andrinse adhesive, Clearfil S3 Bond (Kuraray), a 1-step self-etching or all-in-one adhesive, and Clearfil SE Bond (Kuraray), a 2-step self-etching adhesive. Five-mm-thick composite buildups (Z-250, 3M ESPE) were built and light cured. After water storage for 24 h at 37ºC, the bonded specimens were sectioned into bars (1.0 x 1.0 mm; n = 20 to 30). Microtensile bond strength of normal dentin specimens and caries-affected dentin specimens was measured in a universal testing machine (crosshead speed = 1 mm/min). Data were analyzed using two-way ANOVA and Tukey's post-hoc test (p < 0.05). No significant differences in bond strength values to normal dentin between the three adhesives were found. Adper Scotchbond 1 XT and Clearfil S3 Bond showed significantly lower bond strength values to caries-affected dentin. For Clearfil SE Bond, bond strength values to normal and caries-affected dentin were not significantly different. All the tested simplified adhesives showed similar bond strength values to normal dentin. For the tested 2-step etch-and-rinse adhesive and the all-in-one adhesive, the bond strength values to caries-affected dentin were lower than to normal dentin.

Innovations in bonding to zirconia based ceramics: Part III. Phosphate monomer resin cements

Purpose To compare the bond strength values and the ranking order of three phosphate monomer containing resin cements using microtensile (μTBS) and microshear (μSBS) bond strength tests. Materials and methods Zirconia discs (Procera Zirconia) were bonded to resin composite discs (Filtek Z250) using three different cements (Panavia F 2.0, RelyX UniCem, and Multilink). Two bond strength tests were used to determine zirconia resin bond strength; microtensile bond strength test (μTBS) and microshear bond strength test (μSBS). Ten specimens were tested for each group ( n = 10). Two-way analysis of variance (ANOVA) was used to analyze the data ( α = 0.05). Results There were statistical significant differences in bond strength values and in the ranking order obtained using the two test methods. μTBS reported significant differences in bond strength values, whereas μSBS failed to detect such effect. Both Multilink and Panavia demonstrated basically cohesive failure in the resin cement while RelyX UniCem demonstrated interfacial failure. Conclusion Based on the findings of this study, the data obtained using either μTBS or μSBS could not be directly compared. μTBS was more sensitive to material differences compared to μSBS which failed to detect such differences.