Comparative evaluation of the bonding efficacy of sixth and seventh generation bonding agents: An In-Vitro study

Comparative evaluation of different surface pretreatment methods on the depth of penetration of adhesive resin in sandwich technique: A confocal laser scanning microscopy study

Aim

The aim of the study was to evaluate and compare the depth of penetration of adhesive resin in resin-modified glass ionomer cement (RMGIC) after different surface pretreatment methods using a confocal laser scanning microscope (CLSM).

Methods

Class I cavity preparation was done in 45 freshly extracted premolars and divided into three groups, according to the surface pretreatment of RMGIC which was placed in a thickness of 1 mm in the cavity. In the control group, no pretreatment was done, and other two groups were pretreated with acid etching and air abrasion (AA). The fifth-generation dentin bonding agent mixed with rhodamine B dye 0.1% was applied on RMGIC in all the samples and cured for 15 s. Samples were restored using composite resin and sectioned longitudinally. The depth of penetration of adhesive resin was evaluated using CLSM.

Results

Depth of penetration of adhesive resin was highest with AA (153.70 ± 10.23), followed by acid etching (122.71 ± 12.25) and control group (77.12 ± 6.37).

Conclusion

Based on the findings of this research, AA enhances the depth of penetration of adhesive resin in the RMGIC surface. Thus, AA before placement of composite resin on the RMGIC can be effective in a clinical scenario.

A comparative evaluation of the effect of eugenol exposure time on the bond strength of an etch-and-rinse and a self-etch adhesive to dentin: An in vitro study

Aim

The study aimed to comparatively evaluate the effect of eugenol exposure time on the micro-shear bond strength (μ-SBS) of etch-and-rinse and a self-etch adhesive to dentin.

Materials and Methods

One hundred and twelve teeth samples were prepared from bisectioning 56 freshly extracted human mandibular molars and were randomly divided into 14 subgroups of 8 samples each (n = 8). Three subgroups containing eugenol and a noneugenol-based restorative material were placed on the dentin surface and left for 24 h, 7 days, and 14 days, respectively, and were compared to a control. Two bonding systems were evaluated: one being etch-and-rinse and the other self-etch adhesive. The μ-SBS were calculated and expressed in MPa.

Statistical Analysis

The data were analyzed using mixed model analysis of variance. The level of statistical significance was set at 5%.

Results

There was a statistically significant reduction in the μ-SBS values when the self-etch adhesive was used, after the removal of eugenol-containing cement placed for 24 h. However, the reduction in the μ-SBS values after 7 days or 14 days was not significant.

Conclusion

Exposure to eugenol containing temporary cement for 24 h significantly reduces the μ-SBS of self-etching adhesives to dentin. However, exposure for 1 week or more has minimal effects.

Stress Distribution of Endodontically Treated Tooth MOD Cavity Restored with Ribbon Fiber-Reinforced Composite (Wallpapering Technique) Using Finite Element Method

Purpose

This research aimed to describe the stress distribution of an endodontically treated tooth with a mesio-occluso-distal (MOD) cavity restored with direct composite reinforced with polyethylene and e-glass ribbon fiber.

Methods

This research was a descriptive study using the finite element method. A 3D model of the mandibular first molar solid after endodontic treatment with class II MOD preparation was prepared using Solidworks software. Finite element simulation was carried out using Abaqus software. In the first simulation, 180 N force was applied (vertically 90° perpendicular to the occlusal surface) at four points of loading: the tip of the mesiobuccal and distobuccal cusp, central fossa, and distal marginal ridge. For the second simulation, a 100 N force was applied at a 45° lateral angle to the occlusal surface at two loading points: the lingual slope of the mesiobuccal and distobuccal cusp.

Results

This study showed that the stress concentration was located in the occlusal pit and fissure, CEJ distal area, bifurcation in dentin, and the 1/3 cervical area of root dentin. The stress value generated after vertical and lateral force did not exceed the tooth and restoration's compressive and tensile strength value. The failure occurred at the interface of enamel and composite near the loading point area due to vertical load, both on polyethylene and e-glass fiber ribbon-reinforced composite restoration. Stress distribution of an endodontically treated tooth with a MOD cavity restored with ribbon fiber-reinforced composite using the finite element method showed that the highest stress concentration occurred on the surface close to the loading point, in narrow, concave, and sharp areas, and more apically for endodontically treated teeth.

Conclusion

Neither the tooth nor restoration failed after vertical and horizontal loads. The interface between enamel and composite on the occlusal surface failed.

[Evolution and effectiveness of seventh and eighth generation adhesive systems in direct restorations. a review]

Introduction

: Dental adhesion is responsible for the chemical processes of dentin-enamel union for a correct choice before its application in restorative treatments; it is important to know properly the generation to which it belongs, its properties, application techniques, etc. All this is to ensure success in the procedures to be performed. Currently, adhesive systems have evolved, and 8 generations are available in the market, each with a better-quality standard than the previous one.

Objective

To identify which generation of the adhesive system is the most viable to be applied in direct dental restorative treatments.

Materials and methods

We reviewed and compiled 133 articles published from 20 years ago to date. After analyzing them according to their clinical relevance, 88 were excluded, the remaining articles were reanalyzed, of which only those focused on describing the generations of adhesive systems applied in direct restorations were selected, leaving a total of 56 articles, which included clinical case reports. The Google Scholar search engine, SciELO and databases of interest, such as PubMed, Scopus and Medigraphic, were used, three reviewers independently performed the analysis and search of data, and the keywords were used; adhesive systems, generations of adhesive systems, evolution, and direct restorations.

Results

: 56 articles were evaluated, according to their relationship with the subject and with the information previously sought, it was determined that the seventh generation of adhesive systems is the most viable to be applied in dental treatments, due to the improvements it presents in its characteristics, and the results with good prognosis mentioned by both dental professionals, as in research.

Conclusion

The advancement of technology implies new knowledge; therefore, the effectiveness of adhesive systems has changed significantly. Scientific evidence has shown that seventh-generation adhesives are more effective in direct restorations.

Evaluation of Self-Adhesive Composite Restorations Bond on Primary Canines: An In Vitro Study

Background and purpose The aesthetic requirements for the restoration of the primary anterior teeth of both the child and his parents increased recently, especially with the presence of materials with good mechanical properties capable of giving a good aesthetic shape. However, the challenge remains in the possibility of applying these materials to primary teeth, where the child's cooperation and ability to keep their mouth open during the completion of the restoration is an important challenge for the dentist. Therefore, this study aimed to evaluate the bonding of self-adhesive composite by studying the microleakage in primary canines. Materials and methods The studied sample consisted of 60 extracted primary canines that were divided into three equal groups (n=20) according to the type of restoration: group 1 (experimental) - self-adhesive composite alone, group 2 (experimental) - self-adhesive composite with selective enamel etching, and group 3 (control) - conventional composite with the self-etching bond and selective enamel etching. A Class V cavity was prepared at the cementoenamel junction, 2 mm deep and 1 mm in diameter. In this way, the gingival wall is dentine, while the incisal wall is enamel-dentine. Restorations were placed according to the group to which the tooth belongs. After that, all teeth were subjected to 500 cycles of thermocycling. Then, a methylene blue dye microleakage test was performed, and longitudinal sections of the teeth were made and studied under x20 magnification using a stereo microscope. Results In the gingival wall, the scores of microleakage in the conventional composite group after selective etching were lower than those of the self-adhesive composite groups, with a statistically significant difference. While in the incisal wall, there were no statistically significant differences in the frequencies of the scores of microleakage between the three groups. Conclusions Within the limitations of this study, the conventional composite bonded better to enamel and dentine than self-adhesive composite resin applied alone or after selective enamel etching. The bonding of the self-adhesive composite was lower than that of the conventional composite, and it is not recommended to use it in Class V restorations of primary anterior teeth.

To Compare and Evaluate the Shear Bond Strength of Sixth- and Seventh-generation Bonding Agents

Aim

To compare and evaluate the shear bond strength of sixth and seventh-generation dentin bonding agents.

Materials and methods

Around 75 extracted permanent mandibular premolars were selected and assigned into two groups. The samples were cleaned, cavities were prepared, and the bonding agent was applied and stored in distilled water for 24 hours. Shear bond strength testing was done using a universal testing machine at the crosshead speed of 1 mm/minute. Data were analyzed statistically by one-way analysis of variance (ANOVA) and paired test.

Results

The greatest mean shear bond strength to dentin was exhibited by the sixth-generation dentin bonding agent due to the solvent present, which has a low concentration and low hydrophilicity than the seventh-generation.

Conclusion

Sixth-generation adhesives showed significantly higher mean shear bond strength to dentin than seventh-generation adhesives.

Clinical significance

Bond strength values are gross assessing tools for evaluating the efficacy of restorative bonding materials to dentin. And as the shear bond strength is less technique sensitive to perform, it will highlight the strength at the bonded interface.

How to cite this article

Adyanthaya BR, Gazal S, Mathur M, et al. To Compare and Evaluate the Shear Bond Strength of Sixth- and Seventh-generation Bonding Agents. Int J Clin Pediatr Dent 2022;15(5):525-528.

Degradation and Stabilization of Resin-Dentine Interfaces in Polymeric Dental Adhesives: An Updated Review

Instability of the dentine-resin interface is owed to the partial/incomplete penetration of the resin adhesives in the collagen fibrils. However, interfacial hydrolysis of the resin-matrix hybrid layer complex activates the collagenolytic and esterase enzymes that cause the degradation of the hybrid layer. Adequate hybridization is often prevented due to the water trapped between the interfibrillar spaces of the collagen network. Cyclic fatigue rupture and denaturation of the exposed collagen fibrils have been observed on repeated application of masticatory forces. To prevent interfacial microstructure, various approaches have been explored. Techniques that stabilize the resin–dentine bond have utilized endogenous proteases inhibitors, cross linking agents’ incorporation in the exposed collagen fibrils, an adhesive system free of water, and methods to increase the monomer penetration into the adhesives interface. Therefore, it is important to discover and analyze the causes of interfacial degradation and discover methods to stabilize the hybrid layer to execute new technique and materials. To achieve a predictable and durable adhesive resin, restoration is a solution to the many clinical problems arising due to microleakage, loss of integrity of the restoration, secondary caries, and postoperative sensitivity. To enhance the longevity of the resin-dentine bond strength, several experimental strategies have been carried out to improve the resistance to enzymatic degradation by inhibiting intrinsic collagenolytic activity. In addition, biomimetic remineralization research has advanced considerably to contemporary approaches of both intrafibrillar and extrafibrillar remineralization of dental hard tissues. Thus, in the presence of biomimetic analog complete remineralization of collagen, fibers are identified.

Evaluation of Microleakage of Micro Hybrid Composite Resins versus Chitosan-Incorporated Composite Resins When Restored in Class V Cavities Using Total Etch and Self-Etch Adhesives: An In vitro Study

Aim:

To evaluate the in-vitro microleakage of traditional micro hybrid composite resin and 0.2% chitosan-incorporated composite resin when restored in Class V cavities using total etch versus self-etch adhesives after storing in artificial saliva for 24 h.

Materials and Methodology:

Sixty permanent maxillary premolars collected and Class V cavities were prepared on buccal surface of each tooth (dimensions: mesio-distally 3 mm, occluso cervically 2 mm, and depth of 1.5 mm) and restored with Group 1: micro hybrid (30 teeth) and Group 2: chitosan-incorporated composite (30 teeth), which was further subdivided into: (a) 15 teeth using total-etch adhesives. (b) 15 teeth using self-etch adhesives. Next dye extraction test was carried out using spectrophotometer.

Results:

Comparison within groups: In Group 1: Self-etch demonstrated less microleakage (0.0129) compared with total etch (0.0183). The difference was statistically significant, and in Group 2: No statistically significant difference was found in mean microleakage scores after using either self-etch (0.0118) or total etch adhesives (0.0120).

Conclusion:

It can be concluded that chitosan-incorporated composite seems to have improved mechanical properties with a stable bond when used with either self-etch or total etch adhesives in addition to being antibacterial. It may be clinically useful in restoring Class V cavities in patients with high caries risk. However, further in vitro and in-vivo studies need to be carried out.

Rheological and Mechanical Properties of Resin-Based Materials Applied in Dental Restorations

Resin-based materials have been prevalent for dental restorations over the past few decades and have been widely used for a variety of direct and indirect procedures. Typically, resin-based dental materials are required to be flowable or moldable before setting and can provide adequate mechanical strength after setting. The setting method may include, but is not limited to, light-curing, self-curing or heating. In this review, based on different indications of resin-based dental materials (e.g., dental filling composite, dental bonding agent, resin luting cement), their rheological and mechanical properties were reviewed. Viscous and flexible properties were focused on for materials before setting, while elastic properties and mechanical strength were focused on for materials after setting. At the same time, the factors that may affect their rheological and mechanical properties were discussed. It is anticipated that the insightful information and prospections of this study will be useful to the future development and fabrication of resin-based dental restorative materials.

Comparative evaluation of shear bond strength of sixth- and seventh-generation bonding agents with varying pH - An in vitro study

Introduction

To compare and evaluate the shear bond strength of sixth- and seventh-generation bonding agents with varying pH - an in vitro study.

Materials and Methods

Eighty extracted human premolar teeth were collected and cleaned and polished with pumice and water. The root portion of teeth was resected, and only the coronal portion was embedded in the cold-cure acrylic resin. The labial surface of mounted teeth was prepared with a high-speed handpiece using #245 carbide bur. The samples prepared were divided into four groups, with 20 specimens in each group: Group A: Sixth-generation bonding agent, Adper Prompt L-Pop (APLP) (3M ESPE)Group B: Sixth-generation bonding agent, Xeno III (X III) (Dentsply)Group C: Seventh-generation bonding agent, Adper Easy One (AEO) (3M ESPE)Group D: Seventh-generation bonding agent, Xeno IV (X IV) (Dentsply). Tooth surface were rinsed and dried, and bonding agents were applied on tooth surface. Composite resin (Z-350 XT, 3M ESPE) was placed in a two-layer increment on tooth and was light cured. Specimens were subjected to the universal testing machine in a compression mode force at a crosshead speed of 1 mm/min keeping blade parallel to the adhesive-dentin interface. Shear force required to debond the specimen was recorded in megapascal. The data obtained were analyzed statistically using ANOVA and post hoc test.

Results

AEO (pH = 2.3, Group C seventh generation) showed higher bond strength, and pH values did not influence the shear bond strength significantly in the tested adhesive systems.

Conclusion

The pH values did not influence the shear bond strength significantly in the tested adhesive systems. ADPER EASY ONE (pH= 2.3, GROUP C Seventh Generation) showed higher bond strength followed by XENO IV(pH = 2.1, GROUP D), XENO III (pH = 1.5, GROUP B) on dentinal surface ,where as ADPER PROMPT L POP (pH =0.7 to 1 Sixth Generation, GROUP A) showed lower bond strength.

The effects of Er:YAG, Nd:YAG, and Diode (940nm) Lasers irradiation on Microtensile bond strength of two steps self-etch adhesives

Background and aims

Nowadays, studies show the effective laser irradiation role on the adhesion of bonding agents to the dentin. Therefore, the present study was set to find an appropriate protocol for the use of Nd:YAG, Er:YAG, and Diode lasers during the application of two steps self-etch adhesives in direct dental restorations in order to achieve higher microtensile strength.

Materials and Methods

A total number of 100 extracted healthy teeth were selected. After removing occlusal enamel and exposing dentin, samples randomly divided into ten groups: Group Control (C), two steps self-etch adhesives was applied in accordance with the manufacturer instructions, without using laser systems; Groups Er-YAG, laser (2940 nm, 10 Hz, 0.4w, 40 mJ) irradiated Before applying Primer (Er-BP subgroup), After applying Primer (Er-AP subgroup), After applying Bonding (Er-AB subgroup); Groups Nd-YAG, laser (1064 nm, 10 Hz, 1.2w, 40 mJ) irradiated Before applying Primer (Nd-BP subgroup), After applying Primer (Nd-AP subgroup), After applying Bonding (Nd-AB subgroup); Groups Diode, laser (940 nm, 10 Hz, 0.7w, 70 mJ) irradiated Before applying Primer (D-BP subgroup), After applying Primer (D-AP subgroup), After applying Bonding (D-AB subgroup). After intervention and composite build up, the samples were stored 24 hours in 37°C distilled water. The microtensile strength was measured using the universal testing machine. The data were analyzed by one-way ANOVA test and post hoc Tukey test. (p < 0.05).

Results

The Means and standard deviations of the groups were as follow: C = 30.09 ± 4.21, Er-BP = 18.83 ± 4.21, Er-AP = 14.43 ± 3.12, Er-AB = 19.67 ± 4.96, Nd-BP = 20.35 ± 5.55, Nd-AP = 39.85 ± 4.13, Nd-AB = 18.16 ± 3.36, D-BP = 26.74 ± 5.05, D-AP = 28.11 ± 5.12, D-AB = 37.28 ± 5.61. The mean microtensile strength achieved in groups: Nd-AP and D-AB were significantly higher than control group (p < 0.05). Groups D-BP and D-AP had no significant difference in comparison with control group while the remaining groups had significantly lower values (P < 0.05).

Conclusions

Nd:YAG laser irradiation after applying the primer, and diode laser irradiation after applying the bonding agent, both can improve the microtensile bond strength in two steps self-etch adhesive systems significantly.

The effect of a dentin desensitizer on the shear bond strength of composite to dentin using three different bonding agents: An in vitro study

Objective:

The effect of dentin desensitizer Systemp on the shear bond strength of composite resin to dentin using three different bonding agents, i.e., Prime & Bond NT, Xeno V⁺, and Futurabond DC were evaluated.

Materials and Methods:

Sixty recently extracted human premolars were divided into six groups of ten teeth each. The superficial dentin was etched with 37% phosphoric acid. In Groups I, II, and III, Prime & Bond NT, Xeno V⁺, and Futurabond DC, respectively, were applied to dentin and composite placed. Following application of dentin desensitizer Systemp in Groups IV, V, and VI, Prime & Bond NT, Xeno V⁺, and Futurabond DC, respectively, were applied to dentin and composite placed. The shear bond strength was evaluated. Data obtained were statistically analyzed using one-way analysis of variance, post hoc, and Dunnett's test.

Results:

Following application of dentin desensitizer Systemp, mean shear bond strength increased when Prime & Bond NT bonding agent was used while it decreased for Xeno V⁺ and Futurabond DC bonding agents.

Conclusion:

Within the limitations of this in vitro study, it was observed that following application of dentin desensitizer Systemp, mean shear bond strength may increase or decrease depending on the bonding agents used.

Evaluation of Microleakage with Total Etch, Self Etch and Universal Adhesive Systems in Class V Restorations: An In vitro Study

INTRODUCTION

Adhesive dentistry is overwhelmingly evolving with respect to the dental surgeon's and patient's perspective. Embracing the concept of minimally invasive dentistry which follows minimum intervention performed to produce good adhesion and tooth coloured restoration, in turn makes the newer generation bonding agents more acceptable and appropriate withstanding the demand for stable restoration.

AIM

To study and compare the extent of microleakage between tooth and restoration interface in class V composite resin restorations applying one Total Etch (Adper^TM single bond), two Self Etch (Adper^TM SE Plus, Adper^TM Easy One) and Universal bonding agents using dye penetration method.

MATERIALS AND METHODS

A total of 120 freshly orthodontically extracted human maxillary and mandibular premolars were included in the study. Class V cavities were prepared with a cylindrical diamond bur on the facial surface of each tooth, having approximate dimensions of 3 mm × 2.5 mm × 1.5 mm. Teeth were divided into four groups (30 in each group). Group A Adper^TM single bond 2 (3M ESPE), Group B Adper^TM SE Plus (3M ESPE), Group C Adper^TM Easy One (3M ESPE), Group D Adper^TM Single Bond Universal (3M ESPE) bonding agents were applied as per the manufacturer's instructions and the cavities were then restored with nanohybrid composite resin (Tetric N Ceram Ivoclar Vivadent). Teeth were then thermocycled for 200 cycles at 5°-55°C with 60 seconds of dwell time. Specimens were subjected to a dye leakage test. Microleakage was evaluated using a stereomicroscope. Data was analysed using Kruskal- Wallis, Dunn and Mann-Whitney test to assess the difference in microleakage among various adhesives.

RESULTS

The present study revealed that the microleakage was more at the gingival margin when compared with occlusal and this was found to be statistically significant. At the occlusal margin statistical significant difference was found only between Adper^TM Easy one and Adper^TM SE Plus, on the other hand at gingival margin no statistical significant difference was found.

CONCLUSION

One step self etch agents showed less microleakage than total etches and universal adhesive at occlusal margin. Higher degree of microleakage was observed at gingival margin compared to occlusal margin.

Influence of salivary contamination on the dentin bond strength of two different seventh generation adhesive systems: In vitro study

AIM

To investigate the effect of salivary contamination on the bond strength of two different seventh generation adhesive systems.

MATERIALS AND METHODS

Sixty caries-free human premolars with flat dentin surfaces were randomly divided into six groups of 10 teeth each and bonding was done using seventh-generation bonding agents Adper Easy One (3M ESPE) and Xeno V (Dentsply). Following the bonding procedure, resin composite was bonded to the surfaces using a plastic mould. The prepared specimen with composite cylinders attached were placed in 37°C distilled water for 24 h and then subjected to shear bond strength (SBS) with 0 h universal testing machine and the data were subjected to one-way analysis of variance and unpaired t-test.

RESULTS

Statistical significant difference between the Groups I, II and III in which Adper Easy One was used and similarly for Groups IV, V, and VI in which Xeno V was used. When an intergroup comparison was made using unpaired t-test Group II and Group V showed the nonsignificant difference.

CONCLUSION

Salivary contamination significantly affects the SBS of both the seventh generation dentin bonding agents. However, 2-hydroxyethyl methacryate based adhesive has higher bond strength.

Comparative evaluation of shear bond strength of three resin based dual-cure core build-up materials: An In-vitro study

Aim:

The in-vitro study compared the shear bond strength (SBS) of three recently introduced dual-cure resin based core build-up materials namely ParaCore, FluoroCore, and MultiCore.

Materials and Methods:

One hundred twenty extracted permanent human mandibular molar teeth were taken and sectioned horizontally beneath the dentinoenamel junction to expose the coronal dentin. The specimens obtained were divided into three main groups based on the materials used and then further divided into four sub-groups based on time interval with ten samples each. The dentin surface was treated with the respective adhesives of the groups and then bulk filled with core build-up materials. The attained samples were than subjected to shear loading in Instron Universal Testing Machine. The data were tabulated and statistically analyzed using analysis of variance (ANOVA), Tukey's HSD, and Levene's test.

Results:

The mean SBS was highest in MultiCore at all time periods as compared to FluoroCore and ParaCore and was also higher at 48 h thermocycling in all three groups studied.

Conclusion:

MultiCore dual-cure resin based core build-up material showed the highest mean SBS as compared to FluoroCore and ParaCore. SBS was not negatively affected by thermocycling.

In vitro Comparative Evaluation of Tensile Bond Strength of 6(th), 7(th) and 8(th) Generation Dentin Bonding Agents

BACKGROUND

Newer dentin bonding agents were developed to improve the quality of composite restoration and to reduce time consumption in its application. The aim of the present study was to evaluate tensile bond strength of 6(th), 7(th) and 8(th) generation bonding agents by in vitro method.

MATERIALS AND METHODS

Selected 60 permanent teeth were assigned into 20 in each group (Group I: 6(th) generation bonding agent-Adper SE plus 3M ESPE, Group II: 7(th) generation bonding agent-G-Bond GC Corp Japan and Group III: 8(th) generation dentin adhesives-FuturaBond, DC, Voco, Germany). With high-speed diamond disc, coronal dentin was exposed, and selected dentin bonding agents were applied, followed by composite restoration. All samples were saved in saline for 24 h and tensile bond strength testing was done using a universal testing machine. The obtained data were tabulated and statistically analyzed using ANOVA test.

RESULTS

The tensile bond strength readings for 6(th) generation bonding agent was 32.2465, for 7(th) generation was 31.6734, and for 8(th)-generation dentine bonding agent was 34.74431. The highest tensile bond strength was seen in 8(th) generation bonding agent compared to 6(th) and 7(th) generation bonding agents.

CONCLUSION

From the present study it can be conclude that 8(th) generation dentine adhesive (Futura DC, Voco, Germany) resulted in highest tensile bond strength compared to 6(th) (Adper SE plus, 3M ESPE) and 7(th) generation (G-Bond) dentin bonding agents.

In vitro evaluation of shear bond strength of nanocomposites to dentin

AIMS

To compare the shear bond strength of nanocomposites to dentin using three different types of adhesive systems; and to test few specimens under Scanning Electron Microscope (SEM) for analysing whether the bond failure is adhesive or cohesive.

MATERIALS AND METHODS

Sixty human premolar teeth were selected and were randomly grouped, with 20 specimens in each group: group 1 - fluoride releasing dentin bonding agent; group 2 - antibacterial containing dentin bonding agent; and group 3 - one step conventional self etch adhesive. Each group was treated with its respective bonding agents, composite resin build up was done, and shear bond strengths were tested using Instron Universal testing machine. Few of the specimens were tested under SEM.

RESULTS

The results were statistically analysed using One-way ANOVA and paired t-test. It was observed that group 3 has the highest shear bond strength followed by group 2, and then group 1. Adhesive failures and mixed failures were most frequent types of failures as seen under SEM.

CONCLUSION

Addition of antimicrobial agent decreases the bond strength of dentin bonding agent and addition of fluoride further decreases the bond strength. From SEM results it can be concluded that the zone of failure could not be defined and also that the failure mode was independent of the dentin bonding agent used.

An in vitro evaluation of effect of eugenol exposure time on the shear bond strength of two-step and one-step self-etching adhesives to dentin

Objectives:

To evaluate the effect of the eugenol exposure time of an eugenol-based provisional restorative material on the shear bond strength of two-step and one-step self-etching adhesives to dentin, at three different time intervals of 24 h, 7 days, and 14 days.

Materials and Methods:

Forty extracted human posterior teeth were sectioned mesiodistally to obtain two halves and the resulting 80 halves were randomly assigned into four groups of 20 specimens each (Group-I, -II, -III, and -IV). Cavities of specified dimensions were prepared to expose dentin surface. In Group-I, temporarization was carried out with noneugenol cement (Orafil-G) for 24 h (control group). In Group-II, -III, and -IV, temporarization was carried out with eugenol cement (intermediate restorative material (IRM)) for 24 h, 7 days, and 14 days, respectively. Each group was further divided into two subgroups of 10 teeth each for two-step (Adper SE Plus) and one-step (Adper Easy One) self-etch adhesive systems, respectively. A plastic tube loaded with microhybrid composite resin (Filtek Z-350, 3M) was placed over the dentin surface and light cured. The specimens were subjected to shear stress in universal testing machine.

Results:

Group-II yielded low shear bond strength values compared with Group-III, -IV, and Group-I, which was statistically significant.

Conclusions:

The prior use of eugenol containing temporary restorative material reduced the bond strength of self-etch adhesive systems at 24-h period. No reduction in bond strength at 7 or 14 days exposure was observed with either two-step or one-step self-etch adhesive.