Dentin Pretreatment Research Articles

Effect of Mushroom, Ozone Gas, and Their Combination as Pretreatment Materials on the Bond Strength of Resin Composite to Dentin.

To assess the effect of mushrooms, ozone gas, and their combination as cavity disinfectants on the bonding strength of composite to dentin. The study was conducted on 40 sound premolar teeth randomly divided into four groups. Group I: control group, Group II: mushroom group, Group III: Ozone group, and Group IV: mushroom + ozone gas (combination) group. After the pretreatment of dentin with the previous material the adhesive bonding agents and composite were applied and polymerized. The shear bond strength was measured using the universal testing machine. A sample from each group was evaluated blindly by scanning electron microscope (SEM) to see changes in dentin morphology after treatment. The data were statistically analyzed using one-way ANOVA for inter-group general comparisons while qualitative data were analyzed using the Chi-squared test. The mean value of shear bond strength of the control group was 5.44 ± 1.45, the mushroom group was 7.55 ± 3.46, the ozone group was 10.42 ± 6.55 and the mushroom and ozone group was 7.45 ± 5.26. Comparison between the four groups regarding the shear bond strength indicated that there was a non-significant difference between the tested groups, with a p-value of 0.52. The SEM result showed a continuous hybrid layer in all groups with no gap formation in the combination group. It was concluded that ozone and mushrooms could be employed reliably as cavity disinfectants in permanent teeth without affecting bond strength negatively. The ozone group showed the highest bond strength. Using antibacterial material before restoration is important to help in the prevention of recurrent caries and increase the longevity of restoration, and this should be performed without affecting bond strength. How to cite this article: Ali MAS, Alrafee SA, Metwally NI, et al. Effect of Mushroom, Ozone Gas, and Their Combination as Pretreatment Materials on the Bond Strength of Resin Composite to Dentin. J Contemp Dent Pract 2024;25(10):914-920.

Evaluation of the Effect of Applying Chitosan, Neem, Tulsi, Aloe vera, and Chlorhexidine Solutions on the Shear Bond Strength of Composite to Dentin.

Dentin adhesion is challenging and needs modifications. Newly introduced nature-derived materials may be a useful solution in improving dentin adhesion. The use of natural antimicrobial agents for pretreating prepared dentin surfaces before restoration has become of interest. The present study investigated the effect of natural compounds on the shear bond strength (SBS) of resin composite adhesively bonded to dentin. Sixty extracted human molar teeth were randomly divided into six groups (n= 10); Group I: two-step etch and rinse adhesive system, Adper Single Bond 2 (SB2) (experimental control), Group II: 2.5% Chitosan+etch+SB2, Group III: 15% Neem (Azadirachta indica)+etch+SB2, Group IV: 15% Tulsi (Ocimum sanctum)+etch+SB2, Group V: 2% Aloe vera+etch+SB2, and group VI: 2% Chlorhexidine (CHX)+etch+SB2. Resin composite (Z350, 3M ESPE USA) was placed over the prepared dentin surfaces and was light cured. Data analysis was performed using One-way ANOVA and post hoc Tukey's test (p< 0.05). Neem specimens showed the highest mean SBS, statistically greater than the control (p= 0.042). Other experimental groups showed no significant differences in SBS comparison to the control. The mean SBS values of 2.5% Chitosan, 15% Neem, 15% Tulsi, and 2% Aloe vera were significantly higher than 2% CHX (p= 0.046, p= 0.001, p= 0.010 and p= 0.002 respectively). Dentin pretreatment with Neem may improve the bond strength of a two-step etch and rinse adhesive system. The application of Chitosan, Tulsi, Aloe vera, and CHX did not demonstrate significantly different SBS values from that of the Control, although CHX was lower.

Dentin Pretreatment using Doxycycline Hydrochloride for Improving Push Out Bond Strength

Dentin Pretreatment using Doxycycline Hydrochloride for Improving Push Out Bond Strength

30-Month performance of a 10-MDP based universal adhesive system under mechanical and biological perspectives

Strategies towards the long-term durability of dentin-adhesive interface is the goal of many investigations. As the universal dentin bonding systems (DBS) represents a promissory category, other approaches seem to be refrained. Besides their chemical capacity to bond to dentin, their ability in terms of suppression of dentin metalloproteinases of matrix at the interface is unclear. This study aimed to evaluate the long-term adhesive performance and gelatinolytic activity effect of a 10-MDP-based universal DBS compared with 2 % chlorhexidine digluconate (CHX) as control to connect the understanding of mechanical and biological mechanisms. For this, bond strength to dentin (μTBS) and in situ zymography (Z) at initial, 6-month, and 30-month aging times were run. 102 sound human molars were randomized according to DBS: Adper Single Bond 2 – (SB - MDP-free control); Adper Single Bond Universal in etch-and-rinse (SUER) and self-etching (SUSE) modes. They were subdivided according to dentin pretreatment: W- water or CHX-2% (30s-passive application). The specimens were restored according to the manufacturer's instructions. For μTBS (n = 12), beams (0.64 mm2) were obtained and tested (500N/0.5 mm/min). For Z (n = 5), 0.1 mm-thick slices were incubated with fluorescein-conjugated gelatin (24h/37 °C) and analyzed by confocal laser scanning microscopy. Data were analyzed by three-way ANOVA and Tukey's test (p < 0.05). At 6-month, CHX effectiveness was observed in some circumstances under both tests. However, 30-month assessments evidenced no difference neither among the groups regardless of DBSs nor pretreatment for all comparisons, despite some peculiarities detected under Z. It is concluded that the 10-MDP universal DBS present limited action over the proteolytic action.

Shear bond strength evaluation of bioactive restorative materials on pretreated carious dentin-influence on silver diamine fluoride, potassium iodide, and glutathione.

Silver diamine fluoride (SDF) has gained popularity for its caries-arresting properties, yet its tendency to cause esthetic concerns due to black-staining limits its widespread acceptance. The aim of the study was to evaluate and compare the shear bond strength of Activa BioActive and Giomer restorative material with different protocols of SDF pretreatment on carious dentin. Ninety-two extracted teeth were decoronated at the cementoenamel junction, sectioned 1 mm into dentin, mounted in acrylic resin and randomly divided into four (n = 8) control and six (n = 10) experimental groups. Seventy-six samples underwent demineralization process for a period of 14 days for artificial carious dentin (ACD) formation. The samples categorized based on the dentin substrate (sound or ACD) were subjected to various SDF pretreatment protocols, i.e., only SDF, SDF with potassium iodide (KI), and SDF with glutathione (GSH). Further, bioactive restorative materials, i.e., Activa BioActive and Giomer (Beautifil II), were placed on it, and the samples were subjected to shear bond strength testing. Independent t-test was run to analyze the values obtained. Giomer exhibited better mean bond strength with SDF, SDF + KI, and SDF + GSH (6.56, 4.67, and 3.34 mega-pascals [MPa], respectively) compared to Activa BioActive (3.42, 3.27, and 2.96 MPa, respectively). This study contributes to understanding the interplay between SDF application protocols, esthetic concerns, and the adhesive properties of bioactive restorative materials. Giomer exhibited enhanced bond strength after SDF application, unlike Activa BioActive. In addition, incorporation of KI or GSH adversely affected the bond strength of both the restorative materials, underscoring the critical need for cautious clinical application. This study highlights the importance of selecting appropriate dentin pretreatment agents to maximize the bond strength of bioactive restorative materials with carious dentin. SDF application significantly enhanced the bond strength of Giomer with carious dentin compared to Activa BioActive, thus, making it a good choice for restoring nonesthetic areas. In addition, the application of KI or GSH to mitigate discoloration of carious dentin negatively affected the bond strength of both, Activa BioActive and Giomer. Thus, the clinicians should weigh the benefits of SDF against potential bond strength reductions when using KI or GSH, especially for esthetic restorations.

Influence of Natural Dentin Biomodification Agent on Push-Out Bond Strength and Nanoleakage of Self-Adhesive Resin Cement Luting of Glass-Fiber Posts.

To evaluate the plant-derived compound lignin (LIG) as a pretreatment of intraradicular dentin in combination with EDTA on push-out bond strength (PBS) and nanoleakage of the glass fiber posts (GFPs) cemented using adhesive resin cement. Twenty-eight human incisor roots were prepared for GFP cementation and divided based on dentin pretreatment: (1) CONTROL: no pretreatment, (2) EDTA: 17% EDTA for 3 min, (3) EDTA-LIG: 17% EDTA and 2% lignin for 3 min, (4) EDTA-PAC: 17% EDTA and 2% lignin for 3 min. The GFPs were cemented using the self-adhesive resin cement Multilink Speed. The roots (n = 7) were sectioned into 1 mm-thick discs and subjected to PBS testing after 1 week or 6 months. Nanoleakage was analyzed by SEM. Statistical analysis was performed using two-factor ANOVA and Tukey's test (p < 0.05). Higher PBS was identified for the CONTROL group (p < 0.001). After 6 months, the EDTA-LIG maintained the bond strength with a predominance of mixed failures, while the EDTA-PAC, EDTA, and CONTROL groups showed reduction of bond strength, with a predominance of adhesive failures along with severe silver infiltration in the interface. LIG associated with EDTA as a pretreatment for intraradicular dentin shows significant potential for attaining stable bond strength and interfacial integrity of self-adhesive resin cement to intraradicular dentin.

The effect of stannous fluoride desensitizing toothpaste on immediate dentin sealing ability of universal adhesive in vitro

Background/purposeThe stannous fluoride pretreatment of dentin may compromise the bond formation of the dentinal adhesive system. This study aimed to determine the effect of stannous fluoride (SnF2) desensitizing toothpaste on immediate dentin sealing ability (IDS) of universal adhesive in human intact dentin using dentin permeability test and scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS). Materials and methodsSixty sound dentin specimens were prepared from 60 extracted intact third molars, then treated with 17 % EDTA for 60 s to simulate hypersensitive dentin, and randomly divided into 2 series. Series 1 (dentin permeability test; n = 40) had 4 different treatment groups: (1) universal adhesive (self-etch mode), (2) universal adhesive (total-etch mode), (3) SnF2 pretreatment + universal adhesive (self-etch), (4) SnF2 pretreatment + universal adhesive (total-etch). The IDS of each group was the percentage decrease of hydraulic conductance of dentin after bonding. Series 2 (n = 20) was SEM-EDS analysis of different treated dentin before bonding. The data were analyzed using 2-way ANOVA and Tukey test. ResultsIn groups of no SnF2 pretreatment, the IDS of universal adhesive were 79.53 ± 20.71 and 77.34 ± 18.14 % for self-etch and total-etch mode, respectively. In groups of SnF2 pretreatment, the corresponding values were 71.54 ± 15.56 and 69.56 ± 9.92 %, respectively. Although SnF2 pretreated-dentin had the remarkable signals of silicon and tin, there were no significant reductions in the IDS of universal adhesive (P < 0.05). ConclusionSnF2 desensitizing toothpaste has no adverse effect on the immediate dentin sealing ability of universal adhesive.

The Effect of Dimethyl Sulfoxide on the Microtensile Bond Strength of Universal Adhesives to Dentin.

Objectives: The goal of this investigation was to see how a dentin pretreatment with 5% DMSO affected the microtensile bond strength (μTBS) of universal adhesives. Materials and Methods: In terms of adhesive kind and etching procedure, 32 healthy third human molars were randomly separated into eight groups. Three universal adhesives with etch-and-rinse and self-etch strategies (G-Premio Bond: GPB.ER/SE, All-Bond Universal: ABU.ER/SE, Prime & Bond Elect: PBE.ER/SE), one two-stage self-etch adhesive (Clearfil SE Bond: CSB), and one two-stage etch-and-rinse adhesive (Adper Single Bond 2: ASB) were employed in with and without DMSO modes (group/N=16). Dentin pretreatment was conducted with 50 μl of 5% DMSO, followed by the use of an adhesive. The μTBS of samples was tested. The influence of adhesive type and DMSO application on bond strength was evaluated using a two-way analysis of variance (ANOVA) ( =0.05). Results: The dentin-adhesive μTBS was significantly affected by DMSO administration (P=0.003), type of adhesive (P=0.001), and the combination of DMSO application and type of adhesive (P=0.027). In the DMSO application mode, the average bond strength of universal adhesives with etch and rinse mode was significantly higher than in the non-application mode, but in the self-etch technique, there was no significant difference pattern between DMSO applications and non-application modes in terms of adhesive bond strength. Conclusion: The use of DMSO in an etch-and-rinse technique can dramatically enhance the universal adhesive-dentin μTBS and has promise benefits for clinicians in terms of enhancing dentin bond performance.

Long-term hybrid stability and matrix metalloproteinase inhibition by fucosterol in resin-dentin bonding biomechanics

Fucosterols have been widely studied for their antioxidant, anticancer, and anti-inflammatory properties. However, they have not yet been studied in the field of dentistry. This study aimed to determine whether pretreatment of dentin with fucosterol before resin restoration enhances bond stability in resin-dentin hybrid layers. After applying 0.1, 0.5, and 1.0 wt% fucosterol to demineralized dentin, microtensile bond strength (MTBS) and nanoleakage tests were performed before and after collagenase aging, and the surface was observed using scanning electron microscope (SEM). The fucosterol-treated group showed better bond strength and less nanoleakage both before and after collagenase aging, and the corresponding structures were confirmed using SEM. MMP zymography confirmed that the activity of MMPs was relatively low along the concentration gradient of fucosterol, and the FTIR analysis confirmed the production of collagen crosslinks. In addition, fucosterol exhibits cytotoxicity against Streptococcus mutans, the main cause of dental decay. The results of this study suggest that fucosterol pretreatment improves bond strength and reduces nanoleakage at the resin-dentin interface, possibly through a mechanism involving collagen cross-link formation via the inhibition of endogenous and exogenous MMP activity. This study demonstrates the potential of fucosterol as an MMP inhibitor in dentin, which contributes to long-term resin-dentin bond stability and can be used as a restorative material.

Contemporary Concepts of Adhesive Cementation of Glass-Fiber Posts: A Narrative Review.

(1) Background: Cementation of glass fiber posts to root canals has been associated with various failures, especially debonding. This narrative review aims to present the contemporary concepts concerning the adhesive cementation of glass fiber post and to discuss the optimal management of these factors. (2) Methods: Electronic search was performed in MEDLINE/Pub Med and Google Scholar using selected keywords examining the parameters post length, surface treatment of glass fiber posts, post space preparation and dentin pretreatment, resin cement selection, adhesive systems and hybrid layer formation, and clinical techniques. (3) Results: The search led to the selection of 44 articles. Epoxy resin-based endodontic sealers are recommended and the use of temporary cement in the root canal should be avoided. The minimum length of a glass fiber post adhesively cemented to a root canal is 5 mm. Irrigating the root canals with chlorhexidine, MTAD, or EDTA (alone or in combination with NaOCl) after post space preparation seems to enhance the bond strength. Silane application on the surface of the post seems to be beneficial. Concerning resin cements and adhesive systems, the results were rather inconclusive. Finally, resin cement should be applied inside the root canal with an elongation tip and photoactivation should be delayed. (4) Conclusions: Contemporary concepts of adhesive cementation of glass fiber posts can indeed improve the bond between glass fiber posts, resin cement, and root canal dentin, however, evidence coming from long-term randomized prospective clinical trials is needed in order to obtain safer conclusions.

In-Vitro Evaluation of Shear Bond Strength of Glass Ionomer Cement to Primary Teeth Dentin Pretreated with Silver Diamine Fluoride and Sodium Fluoride Varnish

Aim: To evaluate and compare the shear bond strength (SBS) of glass ionomer cement (GIC) to primary teeth dentin pretreated with silver diamine fluoride (SDF) and sodium fluoride (NaF) varnish. Materials and Methods: A total of 50 non carious human primary molars were used in this study. The teeth were prepared to expose a flat dentin surface, ensuring comparability across samples. The samples were then randomly divided into two groups. Group I: The dentin surface of the primary teeth was pretreated with 38% SDF. Group II: The dentin surface of the primary teeth was pretreated with 5% NaF varnish. Following pretreatment, all samples were restored using GIC. The SBS was evaluated using a universal testing machine, which measures the force required to detach the GIC from the dentin surface. Results: The study found that the mean SBS of Group I (SDF 38%) was significantly higher at 10.11 ± 2.34 MPa compared to Group II (NaF 5%), which had a mean SBS of 6.34 ± 2.56 MPa. This represented a mean difference of 3.77 MPa in favor of the SDF pretreatment group. Conclusion: The primary teeth dentin pretreated with 38% SDF demonstrated a significant increase in SBS to GIC compared to the teeth pretreated with 5% NaF varnish. This suggests that SDF not only acts as a caries-preventive agent but also enhances the bond strength of restorative materials adhered to dentin surfaces. Clinical Significance: The findings hold considerable clinical significance, especially for pediatric dentistry. The use of SDF as a dentin pretreatment can improve the adhesion of GIC to the dentin of primary teeth. This is particularly beneficial given the minimally invasive nature of the procedure, making it an optimal choice for young patients who may find conventional dental procedures distressing. In summary, this study supports the use of SDF over NaF varnish for pretreating primary teeth dentin before GIC restoration, due to the superior bond strength observed. Implementing this can improve the longevity and effectiveness of restorative treatments in primary teeth, offering a viable, simple method that aligns well with pediatric dental care standards.

Influence of pretreating radicular dentin with different polyacrylic acids and isopropanol on the retention of posts

The optimal pretreatment of radicular dentin before cementing a post with glass ionomer cement is unclear. The purpose of this in vitro study was to evaluate the retention of prefabricated tapered titanium posts to endodontically treated teeth after applying different pretreatment protocols on the radicular dentin. The coronal part of 32 single-rooted human teeth was removed 1-mm coronally to the cemento-enamel junction. All specimens received endodontic treatment, and the root canals were prepared with an instrument to a depth of 10mm to receive a titanium post. The dentin walls of each specimen were roughened with a hand-held diamond cutting instrument. The specimens were randomly divided according to the surface treatments into 4 groups (n=8): KW: etched with 20% to 30% polyacrylic acid (PAA) (Ketac Conditioner) and rinsed with water; KWI: etched with 20% to 30% PAA, rinsed with water and 70% isopropanol; DW: etched with 30% to 50% PAA (Durelon Liquid) and rinsed with water; DWI: etched with 30% to 50% PAA, rinsed with water and 70% isopropanol. The prefabricated titanium posts were airborne-particle abraded and cemented with glass ionomer cement. The specimens were fixed in custom-made brass cylindrical holders with autopolymerizing acrylic resin with the holder parallel to the long axis of the post. All specimens were stored in water for 3 days at 37°C. Retention was evaluated using a tensile test with a universal testing machine (Zwick Z010) at a crosshead speed of 2mm/min. Data were statistically analyzed with a 1-way ANOVA, followed by the Tukey post hoc test for pairwise comparisons between groups (α=.05). Mean ±standard deviation retention values ranged from 201.8 ±55.5N (KW) to 328.1 ±70.9N (DWI). Groups DWI and KWI (316 ±58.3N) showed statistically higher retention values than group KW (P<.05) but did not significantly differ from retention values obtained in group DW (P>.05). An additional final rinse with isopropanol after using PAA increased the retention of the post significantly for all groups. Although group DWI achieved the highest retention values, pretreatment of radicular dentin as in group KWI may also be considered.

Effect of Salvadora persica on resin-dentin bond stability

BackgroundThe stability of resin–dentin interfaces is still highly questionable. The aim of this study was to evaluate the effect of Salvadora persica on resin–dentin bond durability.Materials and methodsExtracted human third molars were used to provide mid-coronal dentin, which was treated with 20% Salvadora persica extract for 1 min after acid-etching. Microtensile bond strength and interfacial nanoleakage were evaluated after 24 h and 6 months. A three-point flexure test was used to measure the stiffness of completely demineralized dentin sticks before and after treatment with Salvadora persica extract. The hydroxyproline release test was also used to measure collagen degradation by endogenous dentin proteases. Statistical analysis was performed using two-way ANOVA followed by post hoc Bonferroni test and unpaired t-test. P-values < 0.05 were considered statistically significant.ResultsThe use of Salvadora persica as an additional primer with etch-and-rinse adhesive did not affect the immediate bond strengths and nanoleakage (p > 0.05). After 6 months, the bond strength of the control group decreased (p = 0.007), and nanoleakage increased (p = 0.006), while Salvadora persica group showed no significant difference in bond strength and nanoleakage compared to their 24 h groups (p > 0.05). Salvadora persica increased dentin stiffness and decreased collagen degradation (p < 0.001) compared to their controls.ConclusionSalvadora persica extract pretreatment of acid-etched dentin preserved resin–dentin bonded interface for 6 months.Clinical significanceDurability of resin-dentin bonded interfaces is still highly questionable. Endogenous dentinal matrix metalloproteinases play an important role in degradation of dentinal collagen within such interfaces. Salvadora persica may preserve resin-dentin interfaces for longer periods of time contributing to greater clinical success and longevity of resin composite restorations.

The Impact of Silver Diamine Fluoride Only or Simultaneously With Potassium Iodide Treatment on the Bond Durability of Resin Composite Material on Primary Teeth.

We aim to evaluate the bond strength between resin composite and primary demineralized dentin, pretreated with silver diamine fluoride (SDF) and simultaneous SDF with potassium iodide (KI) after thermal aging. In this in vitrostudy, human carious-free primary molars were randomly assigned into three groups and prepared by exposing the superficial dentin. The primary dentin of each molar was demineralized. The first group (the control) received saline treatment before bond application. SDF was pretreated for the second group, whereas SDF and KI were used for the third. After that, the pretreated dentin was immediately built with resin composite bonded with a universal adhesive and kept wet for 24 hours. Then, the pretreated molars were prepared into beam specimens for microtensile bond strength (µTBS), 16 for each group, and subjected to thermal aging. Lastly, they were tested using a universal testing machine, and the resulting data were analyzed using one-way analysis of variance (ANOVA) followed by Tukey's post hoc test. It was found that the SDF-KI group had a significant difference with both the control and SDF groups (p < 0.05), while the control and SDF groups showed no significant differences (p =0.310). The SDF-KI group had the highest mean value of 11.73 ± 4.39 megapascal (MPa). In contrast, the control group had the lowest mean value of 9.31 ± 3.41 MPa. Post hoc pairwise comparison results showed that SDF-KI pretreatment had a significantly higher strength value than the control and SDF groups. Pretreatment of demineralized primary dentin with SDF-KI does not negatively affect the immediate loading of resin composite. However, under the limitation of this study, KI application after SDF pretreatment is recommended to enhance the bond's durability of resin composite to demineralized dentin.

INFLUENCE OF 2% CHLORHEXIDINE DIGLUCONATE PRE-TREATMENT ON MARGINAL ADAPTATION OF CONVENTIONAL GLASS-IONOMER CEMENT TO DENTIN

The aim of the study was to evaluate the effects of a 2% chlorhexidine digluconate solution on the glass-ionomer cement (GIC) - dentin interface subjected to a simulated cariogenic attack. Forty extracted teeth were used in the study. On each proximal surface a box-only cavity was prepared. Each cavity was initially conditioned using GC Dentin Conditioner (GC Corp., Tokyo, Japan), then the distal cavities were pre-treated with a 2% Chlorhexidine solution. All the cavities were then restored using GIC GC Fuji IX GP Capsule (GC Corp., Tokyo, Japan). Half of the samples (n=40) were submersed in a lactic acid-based solution to simulate the cariogenic attack. The samples were then sectioned and the marginal sealing at the cervical margin was assessed by optical microscopy and scanning electron microscopy. Statistically significant differences were recorded when comparing the samples submersed in demineralizing solution with or without chlorhexidine pre-treatment vs. samples that were not pre-treated and not submersed in acid with significance levels of p=0.044 and p=0.021. In conclusion, the use of 2% chlorhexidine digluconate in dentin pre-treatment do not significantly influence the marginal sealing of glass-ionomer cements to dentin. Seven days of submersion in a lactic acid-based demineralizing solution influences the marginal adaptation of glass ionomer cements to dentin with or without 2% chlorhexidine digluconate pre-treatment.

Effects of Nd:YAG laser irradiation at different energy densities on dentin bond durability under simulated pulpal pressure.

To evaluate the effects of Nd:YAG laser irradiation on the microstructures of dentin surfaces and the long-term bond strength of dentin under simulated pulpal pressure. Under simulated pulp pressure, 30 freshly extracted caries-free third molars were cut into 2-mm-thick dentin samples and then divided into five groups: the control and laser groups (93.3J/cm2; 124.4J/cm2; 155.5J/cm2; 186.6J/cm2). Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), and Vickers hardness were used to analyze the surface morphology, composition, and mechanical properties of the dentin before and after laser irradiation. Another 80 caries-free third molars were removed and treated as described above, and the resin was bonded to the dentin surface with Single Bond Universal (SBU) adhesive in self-etch mode to make stick specimens. Microtensile bond strength (µTBS), confocal laser scanning microscopy (CLSM), and interfacial silver nanoleakage tests before and after 10,000 times thermocycling were then performed to analyze the bonding properties and interfacial durability of each group. SEM observations revealed that the surfaces of all laser group specimens were rough with open dentin tubules. Laser irradiation altered the surface composition of dentin while removing some collagen fibers but did not affect its surface hardness or crystallographic characteristics. Furthermore, laser irradiation with an energy density of 124.4J/cm2 significantly promoted the immediate and aging bond strengths and reduced nanoleakage compared to those of the control group. Under simulated pulp pressure, Nd:YAG laser pretreatment altered the chemical composition of dentin and improved the immediate and long-term bond strength. This study investigated the optimal parameters for Nd:YAG laser pretreatment of dentin, which has potential as a clinical method to strengthen bonding.

Effect of Nisin-based pretreatment solution on dentin bond strength, antibacterial property, and MMP activity of the adhesive interface

ObjectiveTo evaluate the effect of a Nisin-based dentin pretreatment solution on microtensile bond strength, antibacterial activity, and matrix metalloproteinase (MMP) activity of the adhesive interface. Materials and methods100 human molars were sectioned to expose dentin. The teeth were assigned to five groups (n = 20), according to the dentin pretreatment: 0.5%, 1.0%, or 1.5% Nisin; 0.12% chlorhexidine (positive control), and no solution (negative control), and divided into 2 subgroups: no aging, and thermomechanical aging. Specimens were etched with 37% H3PO4 for 15 s and submitted to the dentin pretreatment. Then, they were bonded with an adhesive (Adper Single Bond 2) and a resin composite for microtensile bond strength (μTBS) evaluation. Antibacterial activity against Streptococcus mutans was qualitatively examined using an agar diffusion test. Anti-MMP activity within hybrid layers was examined using in-situ zymography. Data were analyzed with two-factor ANOVA and post-hoc Tukey’s test (α = 0.050). ResultsFor μTBS, significant differences were identified for the factors “solutions” (p = 0.002), “aging” (p = 0.017), and interaction of the two factors (p = 0.002). In the absence of aging, higher μTBS was observed for the group 0.5% Nisin. In the presence of aging, all groups showed similar μTBS values. All Nisin concentrations were effective in inhibiting the growth of S. mutans. Endogenous MMP activity was more significantly inhibited using 0.5% and 1.0% Nisin (p < 0.050). Conclusion0.5% and 1.0% Nisin solutions do not adversely affect resin-dentin bond strength and exhibit a potential bactericidal effect against S. mutans. Both concentrations effectively reduce endogenous gelatinolytic activity within the hybrid layer. Clinical relevanceThe use of 0.5% and 1.0% Nisin solutions for dentin pretreatment potentially contributes to preserving the adhesive interface, increasing the longevity of composite restorations.

Chemical analysis of n-propyl gallate used as pre-treatment for resin-dentin bond strength: In vitro study.

This study aimed to evaluate the effect of n-propyl gallate as pre-treatment for resin-dentin bond strength. The dentin pre-treatments evaluated included propyl gallate of concentrations 0.1% (w/v), 1.0% (w/v), and 10.0% (w/v), as well as glutaraldehyde 5.0% (v/v), and distilled water as a control treatment. Dentin specimens were prepared for Fourier Transformed Infrared Spectroscopy (FT-IR) (n=3/pre-treatment). Pre-treatments were actively applied to dentin blocks before performing the adhesive procedure to composite resin. Microtensile bond strength to dentin (μTBS) (n=8/pre-treatment) was determined after 24h and 6 months of storage. Data were submitted to a two-way ANOVA, followed by Tukey's post hoc test. As for FT-IR, propyl gallate 1%-treated specimens presented higher water, carbonate, collagen, and amide absorbance rates compared to other tested groups, while specimens pre-treated with glutaraldehyde and distilled water presented similar absorbance curves. Regarding μTBS, all concentrations of propyl gallate resulted in statistically significant higher bond strength values than distilled water at 24h. After 6 months of storage, propyl gallate 0.1% was the only group that maintained μTBS over time. Propyl gallate 0.1% might be a suitable dentinal pre-treatment due to being able to present chemical bonds with demineralized dentin and providing resin-dentin bond stability after 6 months of storage.

Effect of Dimethyl Sulfoxide Primer on Microtensile Bond Strength and Micromorphological Pattern of HEMA-free Universal Adhesive to Dry/Wet Dentin After Thermomechanical Aging.

To evaluate the effect of dimethyl sulfoxide (DMSO) primer on microtensile bond strength (μTBS) and the micromorphological pattern of a hydroxyethyl methacrylate (HEMA)-free universal adhesive (UA) applied on wet/dry dentin in etch and rinse (E&R) mode before/after thermomechanical aging. For the μTBS test, the mid-coronal dentin of 80 human mandibular first molars was exposed and etched with 35% phosphoric acid. Teeth were randomly divided into two equal groups: dry and wet dentin (n = 40). Then, each group was subdivided according to dentin pretreatment by DMSO before UA (Gluma Bond Universal, Heraeus Kulzer, Hanau, Germany) application into unpretreated and 10% DMSO/water (OT Primer S100, OT Oy Dent, Turku, Finland) pretreated (n = 20). Resin composite blocks were built up using a specially designed Teflon mold. In every subgroup, both the μTBS test and failure analysis by stereomicroscope were evaluated immediately after 24 h and after thermomechanical aging (n = 10). The data were statistically analyzed using a three-way analysis of variance (ANOVA) (p = 0.05). For the micromorphological pattern, 16 maxillary first premolars were distributed as mentioned in the μTBS test, prepared, and buccolingually sectioned. The dentin-resin interface was examined using an environmental scanning electron microscope (ESEM) (n = 2). Three-way ANOVA revealed that the main effects and interactions between dentin wetness, dentin pretreatment, and evaluation time (thermomechanical aging) were not significant for µTBS (p> 0.05). Adhesive failure was the predominant type in all immediate and delayed specimens. Longer and more prominent resin tags were observed at dentin-resin interfaces after DMSO application. Neither the initial dentin wetness condition, dentin pretreatment, nor thermomechanical aging could affect the dentin bond strength. No correlation was found between the bond strength and the micromorphology findings. Key words:Wet/dry dentin bonding, Microtensile bond strength, Micromorphology, Universal adhesive, Dimethyl sulfoxide, Thermomechanical aging.

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

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. 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. 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. 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.