Effect of phytic acid etchant on resin–dentin bonding: Monomer penetration and stability of dentin collagen

Effect of Phytic Acid Etching and Airborne-Particle Abrasion Treatment on the Resin Bond Strength

Objective

This study aimed to evaluate the bond strength of a universal adhesive to dentin (μTBS) using different time periods of airborne particle abrasion (APA) and two types of acid etching.

Methods

Seventy-two human third molars were divided into 9 groups (n=8) according to dentin pretreatment: APA duration (0, 5, or 10s) and acid etching (no acid - NA, 37% phosphoric acid - PhoA, or 1% phytic acid - PhyA). APA was performed at a 0.5 cm distance and air pressure of 60 psi using 50 μm aluminum oxide particles. Afterwards, two coats of Single Bond Universal adhesive (3M) were applied to the dentin surface. Composite blocks were built using the incremental technique, sectioned into 1×1 mm slices and subjected to microtensile bond strength (μTBS) testing. Fracture patterns and surface topography of each dentinal pretreatment were evaluated using a Scanning electron microscope (SEM). Bond strength data were analyzed using two-way ANOVA and Bonferroni post-hoc tests.

Results

The group that received pretreatment with 5s APA and PhoA presented higher μTBS values among all groups, which was statistically different when compared with the PhoA, 10APA+PhoA, and 5APA+PhyA groups. PhyA did not significantly influence the bond strength of the air-abraded groups. Finally, adhesive failure was considered the predominant failure in all groups.

Conclusion

Dentin pretreated by airborne particle abrasion using aluminum oxide demonstrated an increase in bond strength when abraded for 5 seconds and conditioned with phosphoric acid in a universal adhesive system.

Application of Inositol Hexaphosphate and Inositol in Dental Medicine: An Overview

Phosphorylated inositol hexaphosphate (IP6) is a naturally occurring carbohydrate, and its parent compound, myoinositol (Ins), is abundantly present in plants, particularly in certain high-fiber diets, but also in mammalian cells, where they regulate essential cellular functions. IP6 has profound modulation effects on macrophages, which warrants further research on the therapeutic benefits of IP6 for inflammatory diseases. Here, we review IP6 as a promising compound that has the potential to be used in various areas of dentistry, including endodontics, restorative dentistry, implantology, and oral hygiene products, due to its unique structure and characteristic properties. Available as a dietary supplement, IP6 + Ins has been shown to enhance the anti-inflammatory effect associated with preventing and suppressing the progression of chronic dental inflammatory diseases. IP6 in dentistry is now substantial, and this narrative review presents and discusses the different applications proposed in the literature and gives insights into future use of IP6 in the fields of orthodontics, periodontics, implants, and pediatric dentistry.

Effect of phytic acid on dentinal collagen solubilization and its binding and debinding potentials to dentin

OBJECTIVES

To study phytic acid (IP6) effect on collagen solubilization by assessing hydroxyproline (HYP) release, evaluate its binding to demineralized (DD) and mineralized dentin (MD) and determine the effect of different media on debinding of IP6.

METHODS

Demineralized dentin beams were incubated in 1%, 2% or 3% IP6 and HYP release was evaluated at 1 or 3 weeks and compared to those obtained in untreated control or phosphoric acid (PA)-treated beams. DD or MD powder was treated with 1%, 2% or 3% IP6 and the decrease in IP6 amount was quantitated by ultraviolet-visible spectroscopy. IP6-treated samples were re-suspended in distilled water, ethanol, urea or sodium chloride and the amount of IP6 displaced was determined.

RESULTS

At 1 week, the control group and IP6 showed lower HYP release when compared to PA (P < 0.05). There was no difference among PA, IP6 and control at 3 weeks (P = 0.22). IP6 binding was concentration dependent. 1% IP6 had higher binding potential with MD compared to DD while 2% IP6 showed the opposite result (P<0.05). 3% IP6 had similar binding values between DD and MD (P = 0.53). The highest debinding in MD occurred with urea for 2%, 3% and 1% IP6 in descending manner. Within each concentration of IP6 in DD, the highest debinding effect was reported with ethanol.

CONCLUSIONS

IP6 bound to DD and MD in a concentration-dependent manner. IP6 was debound from DD mostly by the action of ethanol, while in MD, urea caused the most displacement. Collagen solubilization of IP6-treated DD was comparable to untreated DD.

CLINICAL SIGNIFICANCE

These findings add to the potential use of IP6 as an alternative to PA for dentin etching which possibly results in long-term stability of resin-dentin adhesion.

Ex-vivo study about antimicrobial effectiveness of phytic acid against Enterococcus faecalis into root canals

BACKGROUND

Endodontic failure is due to the persistence of microorganisms, especially Enterococcus faecalis, which have become resistant to disinfection measures. Sodium hypochlorite has been traditionally used, whereas phytic acid, a natural irrigant, needs to be further investigated.

METHODS

This ex-vivo study compared the antibacterial effectiveness of 0.9% saline solution, 5% sodium hypochlorite and 5% phytic acid against Enterococcus faecalis ATCC 29212 into the apical root canal third of 96 single-rooted extracted teeth, after 1-minute push-and-pull irrigation - a basic irrigation technique. Survived microorganisms were evaluated both through a traditional colony-forming-unit count and introducing the viability PCR, which precisely detects only DNA from intact cells: dead and damaged cells were excluded thanks to a propidium monoazide dye.

RESULTS

The culture methods showed that 5% sodium hypochlorite (median: 0 CFU/mL) has a significant greater antibacterial effectiveness (P<0.001) compared both to 0.9% saline solution (median: 4.76 CFU/mL) and 5% phytic acid (median: 0.25 CFU/mL). However, 5% phytic acid proved to be significantly more effective (P<0.001) than 0.9% saline solution. The viability PCR did not reveal a significant difference between 5% sodium hypochlorite (median: 4.12×10⁴ survived bacteria) and 0.9% saline solution (median: 8.45×10⁴ survived bacteria). Five percent phytic acid (median: 0.83×10⁴ survived bacteria) was significantly more effective than both 0.9% saline solution (P<0.001) and 5% sodium hypochlorite (P<0.001).

CONCLUSIONS

The findings suggest that 5% phytic acid works against root canal bacteria even with a basic irrigation technique and viability PCR seems to lead to more reliable and sensitive data rather than the culture methods.

Effect of phytic acid on bond strength and interfacial integrity of universal adhesive to deep dentin

Abstract This study investigated the effect of phytic acid (IP6) in different concentrations and application times on microtensile bond strength (µTBS) and interfacial integrity of universal adhesive to deep dentin. Flat deep dentin surfaces of 48 human molars were either etched with 37% phosphoric acid (PA) for 15 sec (control); or received no acid treatment and universal adhesive was applied directly in a self-etch mode (SE); or divided according to IP6 concentration (C) into two main groups: C1, 0.5%, and C2, 1%. Specimens of IP6 groups were further subdivided into three subgroups according to application time of IP6 (T) where; T1, 15 sec; T2, 30 sec and T3, 60 sec. Single Bond Universal Adhesive was then applied and resin composite blocks were built-up. Forty Specimens were then sectioned to produce resin/dentin beams that were used for µTBS testing using a universal testing machine. The remaining eight specimens were sectioned into slabs that were immersed into ammonical silver nitrate solution and nanoleakage was observed using a field emission scanning electron microscope (FE-SEM). The results showed that the application of IP6 in 0.5% and 1% produced significantly higher µTBS and less nanoleakage compared to PA and SE groups. Also, the application of IP6 for 60 sec recorded the highest µTBS and the lowest nanoleakage followed by 30 sec, and 15 sec respectively. Therefore, conditioning of deep dentin with IP6 enhances µTBS and interfacial integrity of universal adhesive to deep dentin in comparison to PA etching or using the universal adhesive in SE mode.

Effect of smear layer removal agents on the microhardness and roughness of radicular dentin

Purpose

To evaluate the effect of phytic acid (IP6) on the surface roughness and microhardness of human root canal dentin and compare it to other smear layer removal agents.

Materials and methods

Fifty extracted human maxillary incisors were sectioned longitudinally into a total of 100 specimens followed by embedding in auto-polymerizing acrylic resin. The specimens were polished and then randomly divided into five groups (n = 20) according to the test solution used to condition root canal dentin: 17% ethylenediaminetetraacetic acid (EDTA); 10% citric acid (CA); 1% IP6; 37% phosphoric acid (PA); or distilled water (control group). Each specimen was treated with a total volume of 1 ml of each solution for 1 min with agitation. Each group was then divided into two subgroups of 10 specimens each. The specimens of the first subgroup were used to determine microhardness, using Vickers hardness tester, and the specimens of the second subgroup were used to measure surface roughness, using a confocal laser scanning microscope. The results were analyzed statistically using one-way ANOVA and Tukey tests, α = 0.05.

Results

All the tested groups exhibited microhardness and surface roughness values that were statistically significantly different when compared with the control group (P < 0.05). The microhardness value obtained with IP6 was significantly lower when compared to EDTA, CA, and the control group, whereas its roughness value was significantly higher compared to the aforementioned groups. However, there was no significant difference between IP6 and PA (P > 0.05).

Conclusions

IP6 and PA showed the lowest microhardness and the highest surface roughness values.

Electric current effects on bond strength, nanoleakage, degree of conversion and dentinal infiltration of adhesive systems

To evaluate the effect of three adhesive systems applied under electric current on microtensile bond strength (μTBS) and degree of conversion (DC). Molar teeth were restored with the aid of three adhesive systems (Adper Single Bond 2-SB2; Clearfil SE Bond-CSE; and Single Bond Universal-SBU) under different electric current intensities (0 μA; 25 μA; and 50 μA). Composite resin blocks were built up in increments (2 mm) and sectioned into 1 × 1 mm beams. The μTBS was tested after 24 h and 1 y distilled water storages. Samples (n = 10) from 24 h to 1 y storages were immersed in a 50% ammoniacal silver nitrate solution and submitted to scanning electron microscopy. The silver nitrate in the hybrid layer was quantified (ImageJ software). The adhesive systems' dentinal infiltration was analyzed using confocal laser scanning microscopy. Fourier transform near infrared spectroscopy was used to measure the DC. The μTBS data were submitted to two-way ANOVA (time vs. electric current) and Bonferroni's test (α = 0.05). Quantitative nanoleakage data were submitted to two-way ANOVA (electric current vs. adhesive) and Bonferroni's test (α = 0.05). DC data were submitted to one-way ANOVA and Tukey's test (α = 0.05) for each adhesive system. The electric current statistically increased the μTBS for SB2 and CSE in 24 h storage, as well as for SB2, CSE and SBU in 1 y storage. No significant difference was observed between storage time for CSE and SBU. When compared to the control, electric currents (25 μA and 50 μA) showed significantly higher DC mean values for SB2 and SBU, and had no effect on CSE. The electric currents (25 μA and 50 μA) reduced the adhesive system's nanoleakage after 1-year storage, and improved the infiltration of SB2 and CSE. Both electric current intensities improved dentinal interface stability.

The effect of phytic acid on enzymatic degradation of dentin

We evaluated the effect of phytic acid on matrix metalloproteinase (MMP)- or cysteine cathepsin (CC)-mediated dentin degradation. Demineralized dentin beams were divided into five groups (n = 12) and treated with 1%, 2%, or 3% phytic acid or with 37% phosphoric acid. Untreated demineralized beams served as controls. After incubation for 1 or 3 wk, dry mass loss was determined and aliquots of incubation media were analysed for cross-linked telopeptide of type I collagen (ICTP) fragments for MMP-mediated and c-terminal telopeptide of type I collagen (CTX) for cathepsin-k-mediated degradation. The direct effect of phytic acid was evaluated using MMP activity assay. Data were analysed using repeated-measures anova. ICTP releases with 1% and 2% phytic acid treatment were statistically significantly lower than those following phosphoric acid treatment at 3 wk. The CTX release for phytic acid-treated beams at 3 wk was not significantly different from that of untreated control beams, but it was significantly lower than that of phosphoric acid-treated beams. Their MMP activities at 3 wk were not significantly different from those of the controls but they were significantly lower than those seen for phosphoric acid-treated beams. Compared to phosphoric acid, phytic acid treatment resulted in a reduced dentinal host-derived endogenous enzymatic activity and collagen degradation.

Postspace pretreatment with 17% ethylenediamine tetraacetic acid, 7% maleic acid, and 1% phytic acid on bond strength of fiber posts luted with a self-adhesive resin cement

Context:

Pretreatment of radicular dentin with chelating agents improves the bond strength of fiber-posts luted with a self-adhesive resin cement.

Aims:

The aim of this study was to assess the effects of the three chelating agents as final rinse of the postspace on bond strength of fiber posts luted with a self-adhesive resin cement.

Settings and Design:

This is an in vitro laboratory study.

Materials and Methods:

Forty-five mandibular premolars were prepared using MTwo rotary system and irrigation was done with 2.5% sodium hypochlorite. Three groups of teeth samples were considered for postspace preparation and irrigated with different solutions: Group 1: 17% ethylenediamine tetraacetic acid (EDTA); Group 2: 7% Maleic acid; Group 3: 1% Phytic acid. This was followed by the luting the posts with RelyX U200. After a week, from each sample, 2 mm thick slices were obtained from each third of the root and subjected to push-out bond strength testing.

Statistical Analysis Used:

One-way analysis of variance and Bonferroni's Post hoc analysis was used for assessing the results. The statistical significance level was set at P < 0.05.

Results:

Bond strength values were improved with maleic acid and phytic acid pretreatment with slight or no significant difference between these groups. A final rinse of postspace with EDTA significantly reduced the bond strength.

Conclusions:

Maleic acid (7%) pretreatment of postspace improved the adhesion of fiber posts luted with a self-adhesive resin cement.

Effect of phytic acid as an endodontic chelator on resin adhesion to sodium hypochlorite-treated dentin

Objectives

Phytic acid (IP6), a naturally occurring agent, has been previously reported as a potential alternative to ethylenediaminetetraacetic acid (EDTA). However, its effect on adhesion to sodium hypochlorite (NaOCl)-treated dentin and its interactions with NaOCl have not been previously reported. Thus, in this study, the effects of IP6 on resin adhesion to NaOCl-treated dentin and the failure mode were investigated and the interactions between the used agents were analyzed.

Materials and Methods

Micro-tensile bond strength (µTBS) testing was performed until failure on dentin treated with either distilled water (control), 5% NaOCl, or 5% NaOCl followed with chelators: 17% EDTA for 1 minute or 1% IP6 for 30 seconds or 1 minute. The failed specimens were assessed under a scanning electron microscope. The reaction of NaOCl with EDTA or IP6 was analyzed in terms of temperature, pH, effervescence, and chlorine odor, and the effects of the resulting mixtures on the color of a stained paper were recorded.

Results

The µTBS values of the control and NaOCl with chelator groups were not significantly different, but were all significantly higher than that of the group treated with NaOCl only. In the failure analysis, a distinctive feature was the presence of resin tags in samples conditioned with IP6 after treatment with NaOCl. The reaction of 1% IP6 with 5% NaOCl was less aggressive than the reaction of the latter with 17% EDTA.

Conclusions

IP6 reversed the adverse effects of NaOCl on resin-dentin adhesion without the chlorine-depleting effect of EDTA.

Corrosion Behavior and Biological Activity of Micro Arc Oxidation Coatings with Berberine on a Pure Magnesium Surface

Bone tissue repair materials can cause problems such as inflammation around the implant, slow bone regeneration, and poor repair quality. In order to solve these problems, a coating was prepared by ultrasonic micro-arc oxidation and self-assembly technology on a pure magnesium substrate. We studied the effect of berberine on the performance of the ultrasonic micro-arc oxidation/polylactic acid and glycolic acid copolymer/berberine (UMAO/PLGA/BR) coating. The chemical and morphological character of the coating was analyzed using scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The corrosion properties were studied by potentiodynamic polarization and electrochemical impedance spectroscopy in a simulated body fluid. The cumulative release of drugs was tested by high-performance liquid chromatography. The results indicate that different amounts of BR can seal the corrosion channel to different extents. These coatings have a self-corrosion current density (Icorr) at least one order of magnitude lower than the UMAO coatings. When the BR content is 3.0 g/L, the self-corrosion current density of the UMAO/PLGA/BR coatings is the lowest (3.14 × 10−8 A/cm2) and the corrosion resistance is improved. UMAO/PLGA/BR coatings have excellent biological activity, which can effectively solve the clinical problem of rapid degradation of pure magnesium and easy infection.

Dentists' performance in dentin-composite resin bonding before and after hands-on course learning

BACKGROUND/PURPOSE

The restoration longevity depends on a high dentin-composite bond quality. This study investigated learning outcomes when using etch-and-rinse and self-etch adhesives among general practitioners in a hands-on bonding test course.

METHODS

We recruited 30 general practitioners to perform shear bond strength (SBS) tests using five adhesives: one Peak® Universal Bond (PUB) etch-and-rinse and four Futurabond DC, Single Bond universal (SBU), Versa Optibond (VOB), and Tetric-N Bond Self-Etch (TNS) self-etch adhesives. SBS tests were conducted at pre-demonstration (pre-demo), post-demonstration (post-demo), and 24-h storage (delayed bonding) stages. SBS data were analyzed with paired Student's t-tests. We defined 17 MPa as "qualified bond strength (QBS)". The percentages of samples with SBS achieving QBS were analyzed using Mantel-Haenszel chi-square tests. The fracture surfaces of the samples were examined by scanning electron microscopy (SEM).

RESULTS

Using PUB caused no significant differences in SBS between pre- and post-demo samples, whereas the SBS of the two self-etch adhesives (SBU and VOB) improved in post-demo samples (p < 0.05). SBU showed the highest percentage of samples with SBS achieving QBS in all three groups (pre-demo = 70%, post-demo = 83%, and delayed bonding = 76.5%). The QBS percentages of VOB and TNS notably improved from 0% (pre-demo) to 71.4% and 23.5% (post-demo), respectively. SEM indicated bubble-like defects at the dentin-resin interfaces in cases of low SBS.

CONCLUSION

Bonding performance is both operator- and product-dependent. The continuing education hands-on course does help dentists to improve the bond strength especially when the self-etch system is used.