Effect of Ethylene diamine tetra acetic acid and sodium hypochlorite solution conditioning on microtensile bond strength of one-step self-etch adhesives

Effect of the use of bromelain associated with bioactive glass-ceramic on dentin/adhesive interface

OBJECTIVES

To evaluate the effect of bromelain associated with Biosilicate on the bond strength (BS) of a universal adhesive system to sound (SD) and caries-affected dentin (CAD), and on the proteolytic activity.

MATERIALS AND METHODS

Cavities were prepared in 360 molars, half submitted to cariogenic challenge. Teeth were separated into groups (n=20): Control-No treatment; CHX-0.12% chlorhexidine; NaOCl-5% sodium hypochlorite; Br5%-5% bromelain; Br10%-10% bromelain; Bio-10% Biosilicate; NaOClBio-NaOCl+Bio; Br5%Bio-Br5%+Bio; Br10%Bio-Br10%+Bio. Following treatments, the adhesive system was applied, and cavities were restored. Samples were sectioned into sticks and stored at 37 °C for 24 h, 6 months, and 1 year. Microtensile BS (2-way ANOVA, Bonferroni's test, α=0.05), fracture patterns (SEM), and adhesive interfaces (TEM) were evaluated. Bacterial collagenase assay and in situ zymography were performed.

RESULTS

In CAD, Br10% presented higher BS (p=0.0208) than Br5%Bio. Br5% presented higher BS (p=0.0033) after 6 months than after 24 h; and association of treatments, higher BS (p<0.05) after aging than after 24 h. Mixed fractures were the most prevalent. Association of treatments promoted a more uniform hybrid layer with embedded Bio particles. Experimental groups presented lower (p<0.0001) relative fluorescence units than Control. Bromelain, associated or not with Bio, showed collagenolytic degradation.

CONCLUSIONS

Bromelain associated with Biosilicate did not affect the BS to SD. In CAD, Br5%Bio decreased immediate BS but had no long-term influence. This association decreased the proteolytic activity.

CLINICAL RELEVANCE

Bromelain and Biosilicate may enhance the longevity of adhesive restorations by inhibiting endogenous proteases.

Effect of Dentin-Disinfection Chemicals on Shear Bond Strength and Microhardness of Resin-Infiltrated Human Dentin in Different Adhesive Protocols

Background and Objectives: Bacteria and its remnants beneath the restorations predispose the tooth to secondary caries and pulpal pathology. Hence, various chemical antibacterial agents are suggested to disinfect the prepared tooth structure before the definitive restorative procedure. This study aimed to investigate the effects of chemical disinfectant solutions on the micro-shear bond strength (µSBS) and microhardness of total-etch and self-etch resin-infiltrated human dentin. Materials and Methods: 100 caries-free intact permanent third molar teeth were vertically sectioned into the buccal and lingual half. All these specimens were mounted on acrylic resin and underlying dentin surfaces were exposed by grinding. Samples were randomly divided into five groups [n = 20] following total-etch and self-etch adhesive protocol. Teeth samples were divided according to surface treatment, as Group I (Control-CNT), Group II (2% chlorhexidine-CHX), Group III (5.25% sodium hypochlorite-NaOCl), Group IV (17% ethylenediaminetetraacetate acid—EDTA) and Group V (10% povidone iodine-PVI). A randomly selected 10 samples from each subgroup were used for µSBS and microhardness tests. After surface treatment and bonding procedure, nono-hybrid composite cylinders with a 3-mm diameter and 2-mm height were directly cured over the dentin substrate. The samples for µSBS were subjected to 5000 thermocycles and tested using a universal testing machine. Microhardness was assessed using a micro-indenter instrument, data were statistically analyzed using a one-way analysis of variance and Tukey HSD tests at p < 0.05. Results: Amongst the chemical disinfectant assessed, 2% CHX did not affect µSBS and produced a marginal reduction in dentin microhardness compared to the control group. The 5.25% NaOCl and 17% EDTA significantly compromised the microhardness of the dentin substrate. Meanwhile, 10% PVI surface treatment resulted in a substantial reduction in µSBS between composite and dentin. Conclusions: CHX with preservation of bonding to dentin and insignificant negative effect on dentin microhardness is a safe option for tooth disinfection.

Evaluation of the Effects of Bromelain and Papain Enzymes on Shear Bond Strength of Composite Resin to Enamel

Aim

This study aimed to evaluate the effects of 6% bromelain and 10% papain enzymes on shear bond strength (SBS) of composite resin to enamel compared to conventional 37% phosphoric acid etching.

Materials and Methods

50 human maxillary premolar teeth were randomly divided into 5 groups (G1–G5/n = 10). In G1 and G2, after etching enamel with 37% phosphoric acid for 15 seconds and washing the surface, 10% papain and 6% bromelain enzymes were used, respectively. In G3 and G4, 6% bromelain or 10% papain enzymes were applied on enamel. In G5, the enamel surface was etched with 37% phosphoric acid for 15 seconds. A two-step etch-and-rinse adhesive system (Adper Single Bond 2) was applied. A nanohybrid composite (Z350) was placed using Teflon molds. All the samples were then subjected to the SBS test using a universal testing machine. Data analysis was performed using a one-way ANOVA test followed by the Tukey test. p values less than 0.05 were considered significant.

Results

Comparison of the mean SBS between G1, G2, and G5 shows no significant differences (p > 0.05); however, they had higher mean SBS compared with G3 and G4 (p < 0.0001).

Conclusions

The shear bond strength of composite to enamel was not affected significantly using either 6% bromelain or 10% papain enzymes after 37% phosphoric acid application. Moreover, 6% bromelain and 10% papain enzymes were not as effective as 37% phosphoric acid alone.

Microtensile Bond Strength of Fiber-Reinforced and Particulate Filler Composite to Coronal and Pulp Chamber Floor Dentin

This ex vivo study aimed to compare the microtensile bond strength of fiber-reinforced and particulate filler composite to coronal and pulp chamber floor dentin using a self-etching adhesive system. Coronal dentin of 40 human molar teeth was exposed by cutting occlusal enamel with a low-speed saw. Teeth were then randomly divided into two groups (n = 20). The first group was left as is, while in the second group, pulp chamber floor dentin was exposed by trepanation. After placement of a self-etching adhesive system (G-aenial Bond, GC, Tokyo, Japan), groups were further divided into two sub-groups (n = 10) according to the type of composite: fiber-reinforced composite (EP, everX Posterior, GC, Tokyo, Japan) and particulate filler composite (GP, G-aenial Posterior, GC, Tokyo, Japan). Then, composite blocks were built up. Sticks (1.0 × 1.0 mm2) were obtained from each specimen by sectioning, then microtensile bond strength (μTBS) test was performed. Statistical analysis included one-way ANOVA test and Student's t-test (p < 0.05). μTBS values were 22.91 ± 14.66 and 24.44 ± 13.72 MPa on coronal dentin, 14.00 ± 5.83 and 12.10 ± 8.89 MPa on pulp chamber floor dentin for EP and GP, respectively. Coronal dentin yielded significantly higher μTBS than pulp chamber floor dentin (p < 0.05), independently from the tested composites.

Effect of Cavity Disinfectants on Dentin Bond Strength and Clinical Success of Composite Restorations-A Systematic Review of In Vitro, In Situ and Clinical Studies

Cavity disinfection becomes an important step before a dental restorative procedure. The disinfection can be obtained cleaning the dental cavity with antimicrobial agents before the use of adhesive systems. The aim of this study was to conduct a systematic review on the effect of different cavity disinfectants on restorations’ adhesion and clinical success. A search was carried out through the Cochrane Library, PubMed, and Web of Science. In vitro and in situ studies reporting results on dentin bond strength tests, and clinical studies published until August 2020, in English, Spanish and Portuguese were included. The methodological quality assessment of the clinical studies was carried out using the Revised Cochrane risk-of-bias tool. Chlorhexidine could preserve adhesion to dentin. EDTA and ethanol had positive results that should be further confirmed. Given the significant lack of scientific evidence, the use of lasers, fluoridated agents, sodium hypochlorite, or other products as cavity disinfectants should be avoided. Chlorhexidine is a safe option for cavity disinfection with adequate preservation of adhesion to dentin. Moreover, future researches should be focused on the efficacy of these disinfectants against cariogenic bacteria and their best application methods.

Evaluating the Effect of Different Conditioning Agents on the Shear Bond Strength of Resin-Modified Glass Ionomers

Aim of the Study

This study aims to evaluate the effects three different conditioning agents on the shear bond strength of resin-modified glass ionomers to human dentin.

Materials and Methods

One hundred and twenty recently extracted, caries-free premolars and molars will be cleaned of debris and disinfected in a 0.5% solution of sodium hypochlorite and sterile water for 30 min. The occlusal surface of each tooth will be reduced using conventional model trimmer with water to produce the dentin surface. Then, three different resin-modified glass ionomer cements (GICs) were triturated and mixed according to the manufacturer's instructions, 10 specimens will be made of each group. The excess restorative material will be removed from matrix band dentin interface with a sharp number 25 bard parker blade. Samples were shear tested with Instron universal testing machine with a crosshead speed of 0.5 mm/min. A shearing bar beveled to a 1 mm thick contact surface area will be placed at the junction of dentin and plastic band matrix. The load required for the failure will be recorded in pounds and converted to megapascals.

Results

Statistical analysis was done with analysis of variance and Tukey's test. Ketac primer as conditioning agent along with Fuji II LC as restorative material had the highest shear bond value whereas intact smear layer which was unmodified dentin had the least value.

Conclusion

Within the limitations of the present study, it can be concluded that surface conditioning of dentin resulted significantly higher bond strength than unconditioned dentin surfaces.

Clinical Significance

Resin-modified glass ionomers have several advantages compared to chemically cured GICs. The advantages include command cure, ease of handling, improved physical properties, and esthetics. Resin.modified glass ionomers have been marketed as direct restorative materials for Class V lesions as well as liners, bases, and luting agents. Several conditioning agents have been evaluated to condition dentin before the application of conventional glass ionomers and resin-modified glass ionomers. These have mainly included polyacrylic acid, citric acid, phosphoric acid, and ethylenediamine tetra.acetic acid. Of late, manufactures have recommended other conditioners to replace polyacrylic acid which includes Ketac primer as one of the conditioning agents.

Effect of Different Protocols in Preconditioning With EDTA in Sclerotic Dentin and Enamel Before Universal Adhesives Applied in Self-etch Mode

Objectives:

The aim of this study was to investigate the effect of different protocols of 17% ethylene diamine tetra-acetic acid (EDTA) conditioning on the etching pattern and immediate bond strength of universal adhesives to enamel and sclerotic dentin.

Methods and Materials:

Forty bovine teeth with sclerotic dentin and 20 human third molars were randomly divided into eight groups resulting from the combination of the main factors surface treatment (none, two-minute EDTA conditioning manual application, 30-second EDTA manual application, 30-second EDTA sonic application) and adhesives systems (Scotchbond Universal Adhesive [SBU] and Prime & Bond Elect [PBE]). Resin-dentin and enamel-dentin bond specimens were prepared and tested under the microtensile bond strength (μTBS) and microshear bond strength (μSBS) tests, respectively. The etching pattern produced on the unground enamel and the sclerotic dentin surfaces under the different protocols and adhesive systems was evaluated under scanning electron microscopy.

Results:

For enamel, only the main factor adhesive was significant (p&lt;0.0001), with SBU showing the highest μSBS. In sclerotic dentin, the lowest mean was observed for the group without EDTA application and the highest mean in the group with EDTA application with the sonic device for 30 seconds. Regardless of the EDTA protocol, the highest means of μTBS were observed for SBU (p&lt;0.05).

Conclusions:

EDTA conditioning improves the bonding performance of universal adhesives in the self-etch mode on sclerotic dentin, mainly when applied for 30 seconds with the aid of a sonic device. EDTA pretreatment also improves the retentive etching pattern of enamel, but it does not result in higher enamel bond strength.

Effect of Enamel and Dentin Surface Treatment on the Self-Adhesive Resin Cement Bond Strength

Abstract The aim of this study was to evaluate the effect of enamel and dentin surface treatment on the micro-shear bond strength of self-adhesive cement. Seventy-two extracted third molars had their crowns embedded in acrylic resin and worn to obtain a flat enamel or dentin surface. The enamel and dentin specimens were randomly assigned to 8 groups (n=12) that were based on surface treatment (11.5% polyacrylic acid solution or no treatment), substrate condition (wet or dry) and storage period (1 day or 90 days), and treated accordingly. Cylinders (1 × 1 mm) were fabricated using self-adhesive resin cement (RelyX U200) following the manufacturer's instructions. The specimens were stored in distilled water at 37 °C for either 1 day or 90 days and subjected to micro-shear bond strength test (EMIC DL 2000 at 0.5 mm/min). After this, the failure type of the specimens was determined. Data were subjected to statistical analysis (a=0.05). According to the results, the 11.5% polyacrylic acid application decreased the bond strength in both enamel and dentin samples. The moist groups showed higher bond strength than the dry ones, regardless of the substrate and surface treatment. Storage period did not influence bond strength. In conclusion, surface treatment with 11.5% polyacrylic acid and absence of moisture decreased the bond strength of the resin-cement (RelyU200), regardless of the storage period.

Effect of sodium ascorbate on the bond strength of all-in-one adhesive systems to NaOCl-treated dentin

BACKGROUND

Ascorbic acid and its salts are low-toxicity products, which are routinely used in food industries as antioxidants. The aim of the present study was to evaluate the effect of 10% sodium ascorbate on the bond strength of two all-in-one adhesive systems to NaOCl-treated dentin.

MATERIAL AND METHODS

After exposing the dentin on the facial surface of 90 sound human premolars and mounting in an acrylic resin mold, the exposed dentin surfaces were polished with 600-grit SiC paper under running water. Then the samples were randomly divided into 6 groups of 15. Groups 1 and 4 were the controls, in which no surface preparation was carried out. In groups 2 and 5 the dentin surfaces were treated with 5.25% NaOCl alone for 10 minutes and in groups 3 and 6 with 5.25% NaOCl for 10 minutes followed by 10% sodium ascorbate for 10 minutes. Then composite resin cylinders, measuring 2 mm in diameter and 2 mm in height, were bonded on the dentin surfaces in groups 1, 2 and 3 with Clearfil S3 Bond and in groups 4, 5 and 6 with Adper Easy One adhesive systems according to manufacturers' instructions. The samples were stored in distilled water for 24 hours at 37°C and then thermocycled. Finally, the samples underwent shear bond strength test in a universal testing machine at a strain rate of 1 mm/min. Data were analyzed with two-way ANOVA and post hoc Tukey tests at α=0.05.

RESULTS

The differences between groups 1 and 2 (P=0.01), 1 and 5 (P=0.003). 1 and 6 (P=0.03) and 4 and 5 (P=0.03) were statistically significant. Two-by-two comparisons did not reveal any significant difference between other groups (P>0.05).

CONCLUSIONS

Use of 10% sodium ascorbate for 10 minutes restored the decreased bond strength of the adhesive systems to that of the control groups.

KEY WORDS

Sodium ascorbate, adhesive systems, all-in-one, bond strength, sodium hypochlorite.

Effect of EDTA Conditioning and Carbodiimide Pretreatment on the Bonding Performance of All-in-One Self-Etch Adhesives

Objective. This study evaluated the effect of ethylenediaminetetraacetic acid (EDTA) conditioning and carbodiimide (EDC) pretreatment on the shear bond strength of two all-in-one self-etch adhesives to dentin. Methods. Flat coronal dentin surfaces were prepared on one hundred and sixty extracted human molars. Teeth were randomly divided into eight groups according to two different self-etch adhesives used [G-Bond and OptiBond-All-In-One] and four different surface pretreatments: (a) adhesive applied following manufacturer's instructions; (b) dentin conditioning with 24% EDTA gel prior to application of adhesive; (c) EDC pretreatment followed by application of adhesive; (d) application of EDC on EDTA conditioned dentin surface followed by application of adhesive. Composite restorations were placed in all the samples. Ten samples from each group were subjected to immediate and delayed (6-month storage in artificial saliva) shear bond strength evaluation. Data collected was subjected to statistical analysis using three-way ANOVA and post hoc Tukey's test at a significance level of p < 0.05.  Results and Conclusion. EDTA preconditioning as well as EDC pretreatment alone had no significant effect on the immediate and delayed bond strengths of either of the adhesives. However, EDC pretreatment on EDTA conditioned dentin surface resulted in preservation of resin-dentin bond strength of both adhesives with no significant fall over six months.

Effect of bromelain enzyme for dentin deproteinization on bond strength of adhesive system

Aims:

To assess the deproteinizing effect of bromelain enzyme and compare it with 5% sodium hypochlorite (NaOCl) on shear bond strength before application of the adhesive system.

Materials and Methods:

A total of 30 extracted human premolars were divided into three groups, each one consisted of 10 teeth. The occlusal surface was wet ground to expose superficial dentin. In Group 1, teeth were etched; in Group 2, teeth were etched and deproteinized with bromelain enzyme; in Group 3, teeth were etched and deproteinized with 5% NaOCl. Upon completion of the adhesive procedures, resin composite was inserted into the plastic tube and light-polymerized. All specimens were stored at 37°C in water for 24 h, and the specimens were transferred to the universal testing machine, and then subjected to shear bond strength analysis at a crosshead speed of 1.0 mm/min.

Statistical Analysis Used:

Data were statistically analyzed using one-way analysis of variance and unpaired t-test at a significance level of 0.05. The statistical analysis was performed using SPSS version 12.0.1 for Windows (SPSS Inc., Chicago, IL, USA).

Results:

The bond strength results were significantly influenced by the application of bromelain enzyme. Statistically significant differences were not demonstrated in control group and NaOCl-treated group. The highest bond strength was seen in bromelain enzyme-treated group.

Conclusions:

Within the limitations of the present study, it was concluded that removal of unsupported collagen fiber with bromelain enzyme after acid etching results in improved bond strength.

Adhesive bonding to pulp chamber dentin after different irrigation regimens

AIM

The aim of the present study was to determine the effect of ethylenediaminetetraacetic acid (EDTA) and NaOCl irrigation on the microleakage and interfacial morphology of adhesives bonded to pulp chamber dentin.

METHODS

The pulp chamber roof of 72 extracted permanent molars was removed. Samples were equally divided into six groups. Pulp chamber dentin was bonded with either Adper Easy One (group 1), Adper Prompt L-Pop (group 2), or Adper Single Bond 2 (Group 3), after irrigation with either normal saline (groups 1a, 2a, 3a) or 17% EDTA and 5.25% NaOCl (groups 1b, 2b, 3b). Composite resin restorations were placed in the pulp chamber. Ten samples per group were subjected to microleakage test and scanning electron microscopic analysis was done in two samples from each group. Data were statistically analyzed using Mann-Whitney and Kruskal Wallis tests at a significance level of P < 0.05.

RESULTS

EDTA and NaOCl irrigation of the pulp chamber significantly reduced microleakage in Adper Easy One. However, it had no significant effect on the microleakage of Adper Prompt L-Pop and Adper Single Bond 2.

CONCLUSIONS

EDTA and NaOCl irrigation of the pulp chamber was not deleterious to the bonding of any of the adhesives tested. While this irrigation regimen had no significant effect on the microleakage of Adper Prompt L-Pop and Adper Single Bond 2, it significantly reduced the microleakage scores in Adper Easy One.

Shear bond strength of resin composite bonded with two adhesives: Influence of Er: YAG laser irradiation distance

BACKGROUND

Dental surfaces prepared with different Er:YAG laser distance may have different characteristics compared with those prepared with conventional instruments. The aim of this study was to investigate the effect of Er:YAG laser irradiation distance from enamel and dentin surfaces on the shear bond strength of composite with self-etch and etch and rinse bonding systems compared with conventional preparation method.

MATERIALS AND METHODS

Two hundred caries-free human third molars were randomly divided into twenty groups (n = 10). Ten groups were designated for enamel surface (E1-E10) and ten for dentin surface (D1-D10). Er: YAG laser (2940 nm) was used on the E1-E8 (240 mJ, 25 Hz) and D1-D8 (140 mJ, 30 Hz) groups at four different distances of 0.5 (standard), 2, 4 and 11 mm. Control groups (E9, E10, D9 and D10) were ground with medium grit diamond bur. The enamel and dentin specimens were divided into two subgroups that were bonded with either Single Bond or Clearfil SE Bond. Resin composite (Z100) was dispensed on prepared dentin and enamel. The shear bond strengths were tested using a universal testing machine. Data were analyzed by SPSS12 statistical software using three way analysis of variance, Tukey and independent t-test. P < 0.05 was considered as significant.

RESULTS

There was a significant difference between enamel and dentin substrates (P < 0.001) and between lased and un-lased groups; the un-lased group had significantly higher bond strength (P < 0.001). Shear bond strength increased significantly with an increase in the laser irradiation distance (P < 0.05) on enamel surfaces (in both bonding agent subgroups) and on dentin surfaces (in the Single Bond subgroup).

CONCLUSION

Laser irradiation decreases shear bond strength. Irradiation distance affects shear bond strength and increasing the distance would decrease the negative effects of laser irradiation.