Dentin Shear Bond Strength Research Articles

Comparison of Different Dentin Deproteinizing Agents on the Shear Bond Strength of Resin-bonded Dentin.

AimTo assess and analyze the resin-bonded dentin in terms of shear bond strength after using deproteinizing agents 5% sodium hypochlorite, 10% sodium hypochlorite, and bromelain.Materials and methodsOverall 140 permanent and intact human premolars were split into four groups, three experimental groups and one control group. In all four groups, the occlusal surface of the teeth was wet ground to expose superficial dentin. In group I, teeth were etched and deproteinized with 5% sodium hypochlorite. In group II, teeth were etched and deproteinized with 10% sodium hypochlorite. In group III, teeth were etched and bromelain was used to deproteinize. In group IV, teeth were etched and no deproteinization was being performed and simultaneous fulfillment of the resin composite and later inserted into the plastic tube and polymerized with light. Samples were stored at 37°C for 24 hours and the later samples were transferred to the universal testing machines to shear bond strength analysis at a speed of 0.5 mm/minute.ResultsThe outcome of the bond strength was significantly influenced by the application of bromelain enzymes. A remarkable difference was observed between the shear bond strength of sodium hypochlorite (5 and 10%) and in the bromelain enzyme-treated group. Group III showed better results than group I and group II.ConclusionThis study concluded that bromelain shear has the maximum value for shear bond strength. Bond strength improved because of removal of unsupported collagen fiber with bromelain enzyme after acid etching.Clinical significanceNatural pineapple enzyme, i.e., bromelain improves bond strength by removal of unsupported collagen fiber. Hence, it is completely safe to use.How to cite this articleKhan R, Sharma N, Garg Y, et al. Comparison of Different Dentin Deproteinizing Agents on the Shear Bond Strength of Resin-bonded Dentin. Int J Clin Pediatr Dent 2020;13(S-1):S69–S77.

Effects of Er:YAG laser pre-treatment on dentin structure and bonding strength of primary teeth: an in vitro study

BackgroundTo investigate the effects of Er:YAG laser pre-treatment on the dentin structure and shear bond strength of primary teeth.MethodsDentin specimens were prepared using freshly extracted intact primary molars and divided randomly into four groups based on the surface treatment applied. The control and etchant groups received no treatment and conventional acid etching treatment, respectively, while the energy and frequency groups received laser surface treatment with variable energy (50–300 mJ) and frequency (5–30 Hz) parameters. The morphology was observed using scanning electron microscopy. The surface-treated dentin slices were bonded to resin tablets, followed by thermocycle treatment. The shear strength was determined using a universal testing machine and de-bonded surfaces were observed using a stereomicroscope.ResultsSEM observation showed that the surface morphology of the dentin slices changed after etching as well as after Er:YAG laser pre-treatment with different energy and frequency values. The dentin tubules opened within a specific energy (50–200 mJ) and frequency (5–20 Hz) range. Beyond this range, the intertubular dentin showed cracks and structural disintegration. Shear strength tests showed no significant changes after acid etching. The shear strength increased significantly (P < 0.05) after Er:YAG laser pre-treatment compared with that of the control group. The shear strength increased within the same energy (50–200 mJ) and frequency (5–20 Hz) range as the tubule opening, but not significantly (P > 0.05). The most common mode of interface failure was adhesive (interface) failure, followed by mixed and resin cohesive failure.ConclusionsPre-treatment using Er:YAG laser opens the dentinal tubules without the formation of a smear layer and improves the bonding strength between the primary teeth dentin and the resin composites.

Monomer conversion, biaxial flexural strength, apatite forming ability of experimental dual-cured and self-adhesive dental composites containing calcium phosphate and nisin.

The aim was to develop dual-cured, self-adhesive composites containing monocalcium phosphate monohydrate (MCPM, 8 or 4 wt%) and nisin (6 or 3 wt%) with added adhesive monomer. The effect of additives on monomer conversion (MC), biaxial flexural strength (BFS), dentin shear bond strength (SBS), and surface apatite formation were examined. All experimental composites showed light-activated MC (70-75%) higher than the commercial self-adhesive composite (Vertise Flow; VF, 65%). The additives reduced BFS of the composites from 217 to 133 MPa. SBS of the experimental composites (2-6 MPa) was lower than that of VF (12 MPa). Rising MCPM level enabled apatite-like crystals precipitated on the surface of composites after immersion in simulated body fluid for 4 weeks. The additives showed negligible effect on MC and SBS. Rising level of additives reduced strength of the composites but the values were still higher than that required by the standard.

Shear bond strength of three solvent-containing adhesive with different bulk fill composites

The aim of this study was to compare, under varying conditions, the dentin shear bond strength (SBS) of three solvent-containing (acetone, ethanol, and water) self-etch adhesive with acetone-containing self-etch adhesive and ethanol/water-containing self-etch adhesive. One-hundred non-carious molar teeth were divided into 10 groups of ten specimens each. Kerr Optibond All-In-One (containing acetone, ethanol, and water), Ivoclar Tetric N-Bond Universal (containing ethanol and water), and Shofu BeautiBond (containing acetone) were used as adhesives. The comparisons were made only between adhesives containing common solvents. Three bulk-fill resin composites, Kerr Sonicfill 2, Ivoclar Tetric N-Ceram Bulk Fill, and Shofu Beautifil-Bulk, were chosen for preparation of two-millimeter blocks of composites. Specimens were tested in a universal testing machine (Shimadzu, Japan) in shear to failure at 0.5 mm/min. The shear bond strengths were tested under two conditions: immediately and after 10,000 thermal cycling. The mean values were compared using analysis of variance (ANOVA]. A significance level of p < 0.05 was used in all tests. Failures were categorized into four classes: adhesive failure, cohesive failure in dentin, cohesive failure in the composite, and mix-type failure. Tetric N-Ceram Bulk Fill + Tetric N-Bond Universal showed the highest SBS values both two conditions. The megapascal pressure unit (MPa) was 19.38 (± 3.06) in immediate group, while the MPa after thermocycle aging was 10.68 (± 2.5]. The SBS of three solvent-containing adhesives was not affected by the content of bulk-fill composites. After thermal aging, there was a significant decrease in the SBS of all groups.

Characteristics of 10-Methacryloyloxidecyl Dihydrogen Phosphate Monomer in Self-Etching Two-Bottled Dental Adhesive System: Comparison with Commercial Products.

Dentin bonding is a key in restorative dentistry. Here, we developed a self-etching two-bottle adhesive system containing 10-methacryloyloxidecyl dihydrogen phosphate monomer (MDP) and the physical, mechanical, and biocompatible properties were evaluated. The characteristics of MDP were analyzed using nuclear magnetic resonance (NMR). Tests for water sorption and solubility, the shear-bond strengths to dentin and enamel, and cytotoxicity were performed. The newly-blended experimental group showed the lowest thickness and water sorption and solubility values. The shear bond strength of enamel and dentin were comparable to control groups (the three other products were ClearfilTM, UniFil®, and AdheSE®). All test groups showed 60% of cell viability. In this study, the properties of the newly-synthesized adhesive are comparable with the others. The fundamental goal of this study is to get the MDP patent released, as it is intended for domestic production. For this purpose, this dentin adhesive was developed and compared with the commercial product.

Development of novel self-adhesive resin cement with antibacterial and self-healing properties

This study aimed to develop novel self-adhesive resin cement with antibacterial and self-healing properties. Furthermore, the dentin bonding strength, mechanical properties, self-healing efficiency, and antibacterial property of the developed cement were measured. Novel nano-antibacterial inorganic fillers that contain quaternary ammonium salts with long-chain alkyls were synthesized. These fillers were added into self-adhesive resin cement containing self-healing microcapsules at mass fractions of 0, 2.5%, 5.0%, 7.5%, or 10.0%. The dentin shear bonding test was used to test the bonding strength, whereas the flexural test was used to measure the flexural strength and elastic modulus of the cement. The single-edge V-notched beam method was used to measure self-healing efficiency, and human dental plaque microcosm biofilms were chosen to calculate the antibacterial property. The dentin shear bond strength significantly decreased when the mass fraction of the nano-antibacterial inorganic fillers in the novel cement reached 7.5% (P<0.05). The incorporation of 0, 2.5%, 5.0%, 7.5%, or 10.0% mass fraction of nano-antibacterial inorganic fillers did not adversely affect the flexural strength, elastic modulus, fracture toughness, and self-healing efficiency of the cement (P>0.1). Resin cement containing 2.5% mass fraction or more nano-antibacterial inorganic fillers significantly inhibited the metabolic activity of dental plaque microcosm biofilms, indicating strong antibacterial potency (P<0.05). The novel self-adhesive resin cement exhibited promising antibacterial and self-healing properties, which enable the cement to be used for dental applications.

The influence of Er:YAG laser treatment on the shear bond strength of enamel and dentin: a systematic review and meta-analysis.

Tooth preparation is one of the factors that affect the bond strength of composite to teeth, and the method of preparation affects dentin morphology. Several disadvantages have been observed for the conventional technique. Currently, Er:YAG laser is a good treatment option and has been used to prepare hard dental tissue; it enables conservative preparation without damage to the pulp. Though Er:YAG laser is a promising alternative for preparation of the dentin surface, the bond strengths of Er:YAG-lased tooth substrates to composite reported in the literature have been confusing and even contradictory. The aim of the present study was to investigate the effect of Er:YAG laser irradiation, compared with conventional methods, on the shear bond strength of enamel and dentin. The databases PubMed, EMBASE, Springer, Wiley-Blackwell, EBSCO, and the China Academic Journals Full-text Database were searched for relevant studies in English or Chinese. Full-text articles were selected that involved shear bond strength after using the Er:YAG laser and conventional methods. Review Manager 5.0 was used to estimate the effects of the results among selected articles. Forest plots, sensitivity analyses, and bias analyses were also conducted for the articles. Both in dentin and in enamel, the shear bond strength after using Er:YAG laser was significantly higher than that of the blank control (conventionally treated) group. Differences were not significant between studies that used burs in comparison with phosphoric acid. There was high heterogeneity of shear bond strength between different groups, and low numbers of studies and contradictory results may be the main reasons for this. A funnel plot indicated that some publication bias existed. The shear bond strength after Er:YAG laser preparation was significantly higher than that of the blank control (conventionally treated) group. Er:YAG laser is a safe and convenient alternative procedure, and has some advantages over traditional methods.

Influence of a Primer Resembling Universal Adhesive on the Bonding Effectiveness of an Experimental Two-step Self-etch Adhesive.

Purpose: To investigate the effect of application of a primer resembling a universal adhesive with or without light irradiation followed by a hydrophobic bonding agent on bonding effectiveness, based on shear bond strength (SBS) and shear fatigue strength (SFS) tests. Materials and Methods: An experimental two-step self-etch adhesive (BZF) that comprises a primer resembling a universal adhesive (BZP) and a hydrophobic bonding agent (BZB) were used. The two-step self-etch adhesive, Clearfil SE Bond 2 (SE), served as a comparison. Three experiments were conducted. Experiment 1: (1) BZP alone without light irradiation (BZP w/o); (2) BZP alone with light irradiation (BZP w/); (3) BZP without light irradiation followed by BZB (BZPB w/o); (4) BZP with light irradiation followed by BZB (BZPB w/). Experiment 2: (1) BZPB w/o, (2) SE primer + BZ bonding agent (SEP + BZB), and (3) SE primer + SE bonding agent (SEPB). The bonded specimens of experiment 1 and 2 were subjected to SBS tests. Experiment 3: Bonded specimens following the same experimental protocol as experiment 2 were subjected to SFS tests. Results: BZPB showed significantly higher mean enamel and dentin SBS than did BZP. BZPB showed significantly higher SBS without light irradiation than with light irradiation to both substrates. The group of BZPB without light irradiation showed significantly higher SBS than the group of BZPB with light irradiation to both substrates. For experiments 2 and 3, although no significant differences were found in SBS among groups for enamel, SEP + BZB showed a significantly lower SBS and SFS than other groups for dentin. Conclusions: BZF showed bonding performance equivalent to that of the gold standard Clearfil SE Bond 2.

Preparation, Characterization and Incorporation of Ascorbic Acid Coated Superparamagnetic Fe3O4 Nanoparticles into Universal Dental Adhesives to Enhance their Dentin Bond Strength and Stability

Aims (Purpose): The study aims were to prepare, characterize, and incorporate colloidal suspension containing Ascorbic Acid Coated Superparamagnetic Nanoparticles (AA-SPN) into two universal adhesives to increase the dentin Shear Bond Strength (SBS) and stability by subjecting them to external magnetic field. Settings and Design: An invitro study. Methods and Material: A colloidal suspension of AA-SPN was prepared, characterized, and incorporated into All Bond universal (Bisco, USA) and Prime&Bond universal (Dentsply, Sirona) at 2% by mass. Sixty-four freshly extracted third-molars were divided randomly into four groups, i.e., GI: All Bond Universal (control), GII: All Bond Universal (2%-incorporated), GIII: Prime&Bond universal (control), and GIV: Prime&Bond universal (2%-incorporated). GII and GIV are subjected to 1min magnetic force before adhesive curing. The teeth were restored with Filtek Z350 composite (3M ESPE, USA). Each group was subdivided into two subgroups of 8 teeth each. The first subgroup subjected to thermocycling followed by 1-day water storage, and the second subgroup subjected to thermocycling followed by 6- months water aging before testing the SBS. Statistical analysis used: Statistical analysis was conducted by independent variable t-test performed by using IBM-SPSS program version 22. Results: GII and GIV showed significantly higher (p<0.05) immediate SBS after thermocycling, and maintained a significantly higher bond strength after 6 months water aging in comparison to their control groups. GIV showed significantly higher SBS in comparison to the GII. Groups I, II showed the lowest SBS after 6 months of water aging. Conclusions: Universal adhesives containing 2% AA-SPN subjected to external magnetic field significantly improved the immediate and delayed shear bond strength values compared to their corresponding control adhesives. Significance: The synergistic actions of superparamagnetism of the magnetite nanoparticles in response to magnetic field, and the medicinal values of vitamin C including collagen cross linking and MMPs inhibition, significantly increased and maintained the bond strength of universal adhesive to sound dentin when subjected to external magnetic field in comparison to the non-incorporated adhesives

Dentin bond strength of bioactive cement in comparison to conventional resin cement when photosensitized with Er,Cr:YSGG Laser.

Objective:The purpose of the present study was to assess dentin shear bond strength (SBS) and mode of bond failure of bioactive cement (BA) in comparison to conventional resin cement when photosensitized by Er,Cr: YSGG Laser (ECL).Methods:The present in-vitro study was carried out from March 2019 to May 2019. Sixty permanent non-carious, intact, non-fractured molars were isolated and mounted vertically in acrylic resin. Buccal surface of each molar tooth was ground, polished and surface treated with ECL. Ketac conditioner was applied on the surface washed and air dried surface. Tetric -N-Bond adhesive was applied on forty-five samples and light cured. The specimens were allocated into four groups (n=15) according to the type of cement used i.e., Calibra (C), BA, Variolink II (V) and Maxcem-Elite (ME). For SBS testing was performed using the universal testing machine. Eight samples from each group were assessed for modes of failure. Means and standard deviations were compared using analysis of variance (ANOVA) and Tukey’s post hoc test at a significance level of p < 0.05.Results:The highest mean SBS was observed in group ECL-C (21.55±3.08). The lowest mean SBS was displayed in group ECL-ME (14.25±3.55). Mean SBS values for group ECL-C (21.55±3.08) and group ECL-V (20.74±4.15) were comparable (p <0.05). Similarly, SBS values of group ECL-BA (15.48±3.62) and group ECL-ME (14.25±3.55) were comparable (p <0.05).Conclusion:Dentin surface conditioned with Er,Cr: YSGG and bonded to C and V cements exhibit favourable bond strength values.

Influence of Expasyl and Viscostat on Bond Strength of Resin Composite to Dentin with Different Adhesives

The aim of the present study was to evaluate the influence of gingival retraction agents and different bonding regimes on the shear bond strength (SBS) of dentin to resin composite. Sixty human teeth were divided into six groups (n = 10) based different combinations of hemostatic agents (Viscostat and Expasyl) and dentin bonding regimes [Total-etch (TE) and self-etch (SE)]. Group A1, Expasyl and TE; group A2: Expasyl and SE; group B1: Viscostat and TE; group B2: Viscostat and SE, group C1 (control): No hemostatic agent and TE; group C2 (control): No hemostatic agent and SE. Composite build-ups (Tetric N Ceram) were performed after dentin treatments and SBS was assessed using universal testing machine. Failure analysis was performed with a stereomicroscope and classified as adhesive, cohesive and admixed. Data was analysed using ANOVA and multiple comparisons test. The maximum and minimum SBS was displayed by specimens in group C1 (36 59 ± 5 94 MPa) and group B2 (17 95 ± 2 52 MPa) respectively. Control groups (C1 and C2) showed statistically comparable SBS, which was significantly higher in comparison to experimental groups (A1, A2, B1, and B2) (p &lt; 0.05). Hemostatic agents inhibited the adhesive bond strength of composite to tooth dentin. Reversal effect of total-etch and self-etch bonding regimes on hemostatic agent treated dentin SBS was minimal.

The Effects of Aluminablasting on Bond Durability Between Universal Adhesives and Tooth Substrate.

The aim of this study was to determine the effect of aluminablasting on the bond durability of universal adhesives and adherent surface characteristics. Adhese Universal (Ivoclar Vivadent), All-Bond Universal (Bisco), Bondmer Lightless (Tokuyama Dental), G-Premio Bond (GC), and Scotchbond Universal (3M ESPE) were used in self-etch mode. The prepared bovine enamel and dentin specimens were divided into two groups based on whether they received an aluminablasting prior to application of the universal adhesives. The resin composite bonded specimens were stored in distilled water at 37°C for 24 hours, following which the shear bond strength (SBS) of half of the specimens was measured (24-hour group). The other half was subjected to 30,000 thermal cycles between 5 and 55°C before SBS measurement (TC group). Surface roughness (Ra) and surface free energy (SFE) of the adherent surfaces were also measured, and scanning electron microscopy observation and scanning electron microscopy/energy-dispersive X-ray analysis were carried out. Most of the adhesives did not show any significant differences in enamel SBS values between the two pretreatment groups, regardless of the storage condition. However, the dentin SBS values were significantly lower in specimens that underwent aluminablasting compared with those that did not, irrespective of their storage conditions. Significantly higher Ra and SFE values were observed in the enamel and dentin of specimens that underwent aluminablasting. Although aluminablasting increased the Ra and SFE values of enamel and dentin, its effect on the SBS value was dependent on the tooth substrate. In addition to C, O, Na, Mg, P, and Ca, the element Al was detected in the enamel and dentin of samples that had undergone aluminablasting. These results suggest that although aluminablasting of the tooth surface is thought to be effective for modification of the adherent surface, it may not enhance enamel bond performance and may also adversely affect the dentin bond effectiveness of the universal adhesives.

Influence of Application Time on Dentin Bond Performance in Different Etching Modes of Universal Adhesives.

We attempted to determine the effect of universal adhesive application time on dentin bond performance in different etching modes based on shear bond strength (SBS) tests and surface free energy (SFE) measurements. The five universal adhesives used were Adhese Universal (AU), Clearfil Universal Bond Quick (CQ), G-Premio Bond (GP), Scotchbond Universal (SU), and Tokuyama Universal Bond (TU). Bovine dentin specimens were divided into four groups of 10 for each adhesive. SBS and SFE were determined after applying the following surface treatments: 1) self-etch (SE) mode with immediate air blowing after adhesive application (IA treatment), 2) SE mode with prolonged application time (PA treatment), 3) etch-and-rinse (ER) mode with IA treatment, and 4) ER mode with PA treatment. Bonded specimens were subjected to SBS testing. The SFE of adhesive-treated dentin surfaces was measured after rinsing with acetone and water. Three-way analysis of variance revealed that dentin SBS values (p<0.001) were significantly influenced by the factors of adhesive type and application duration, but the factor of pre-etching was not significant (p=0.985). The manufacturer's instructions require longer application times for AU and SU, which showed significantly lower SBS values in IA than in PA treatment in both etching modes. However, the difference in the other adhesives was not significant between the IA and PA treatments in either etching mode. The total SFE (γS) was dependent on the adhesive and etching mode. The γS value of the initial group (SiC paper ground group) at baseline was 69.5 (mN·m-1) and that of the pre-etching group at baseline was 30.6 (mN·m-1). For all the adhesives, γS in SE mode showed significantly higher values than in ER mode, regardless of the application time. In SE mode, almost all universal adhesives tested showed lower γS values in PA treatment than in IA treatment. For ER mode, all the adhesives showed significantly higher γS values than those of the pre-etching baseline, regardless of the application time. Most adhesives did not show any significant differences in γS values between IA and PA treatments, regardless of etching mode.

Evaluation of mechanical and adhesion properties of glass ionomer cement incorporating nano-sized hydroxyapatite particles.

Glass ionomer cement is a widely used luting agent for indirect restorations but presents inferior mechanical properties compared to resin cement due to its low elastic modulus. This study evaluated the mechanical and adhesion properties of glass ionomer luting cements reinforced with nano-sized hydroxyapatite particles (HA). The nano-sized HA particles were synthesized using the co-precipitation technique and the resulting precipitate was characterized using X-ray diffraction analysis (XRD), field emission scanning electron (FESEM) and transmission electron microscopy (TEM). HA particles were incorporated into the glass powder (FUJI I, GC) and the luting agent was manipulated in a liquid to powder ratio of 3:1 into 6% by weight after determining the best ratio. The flexural strength of the luting agent and shear bond strength of dentin were analyzed and compared to other luting agents namely, (a) glass ionomer (FUJI I), (b) resin-modified glass ionomer (RelyX Luting Plus) and (c) adhesive resin cement (RelyX U200). Failure types after debonding from dentin were evaluated under SEM. Flexural strength and bond strength data were analyzed using one-way ANOVA and Tukey's tests (alpha = 0.001). Addition of 6 w% HA particles in the range of 80-150nm enhanced the flexural strength (30.97 ± 5.9 versus 11.65 ± 5.63) and shear bond strength (0.97 ± 0.41 versus 0.39 ± 0.16) of a conventional glass ionomer luting agent significantly compared to the non-reinforced ones when manipulated at a liquid to powder ratio of 3:1 (P < 0.001). While conventional glass ionomer, HA-reinforced glass ionomer and resin-modified glass ionomer specimens showed exclusively mixed type of failures, adhesive resin cement showed cohesive failures within the resin cement. Increased mechanical and adhesion potential of the experimental glass ionomer luting agent after incorporation of HA particles could expand the scope of application of this cement.

Comparative Study of Cementum and Dentin Shear Bond Strength using Resin Composite with Universal Adhesive System and Resin Modified Glass Ionomer

Objective: to compare the shear bond strength of resin composite using universal adhesive system containing MDP and resin modified glass ionomer cement to cementum and compare the results with those of cervical dentin. Materials and methods: A total of 12 lower premolars were used in this study, they were sectioned just above the cemento-enamel junction, the roots were then sectioned into two halves and divided into two main groups according to the tooth substrate in which group 1) Cervical dentin and group 2) Cementum. They were further subdivided into two subgroups according to the material used where n= 6 subgroup 1) Resin composite (Brilliant Ever-Glow) using universal adhesive (One coat 7 universal), subgroup 2) Resin modified glass ionomer (Fuji II LC). Shear bond strength was then evaluated for all specimens and statistically analyzed. Results: There was statistically significant difference between resin composite using universal adhesive system and resin modified glass ionomer when applied on cementum. While on comparing the resin composite using universal adhesive system and resin modified glass ionomer on cervical dentin it showed no statistically significant difference. Meanwhile no statistically significant difference was found between cervical dentin and cementum when using resin composite with universal adhesive system. Comparing resin modified glass ionomer on dentin and cementum there was also no statistical difference. Conclusion: using universal adhesive containing MDP with resin composite it showed the same bond strength to cervical dentin and cementum. While the resin modified glass ionomer showed higher bond strength to cementum than that of the universal adhesive system.

Bond strength and adhesive interfacial micromorphology of self-adhesive resin cements: Effect of reduced times of pre-etching

BackgroundAlthough acid-etching could increase enamel bond strength of self-adhesive (SA) cements, it may lead to negative effect on dentin. The aim of this study was to assess the effect of shortening of phosphoric acid pre-etching duration on enamel/ dentin shear bond strength (SBS) and interfacial microstructure of Panavia SA Luting Plus (PASA) and Bifix SE (BXSE).Material and MethodsFor both enamel and dentin, effect of pre-etching time was significant (p<0.001); however, effect of cement brand and the interaction of two factors was significant only for dentin (p≤0.008). Three pre-etching times increased SBS of both cements to enamel and BXSE to dentin. In case of dentin SBS of PASA, this improvement was significant only for 5 and 10 seconds (p<0.001). Adding acid-etching in the three times to both cements similarly improved interfacial adaptation, particularly for enamel.ResultsThe evaluations of the biofilm elimination showed results that indicate that the 4% sodium hypochlorite group with positive pressure irrigation presented significant differences with the group that had irrigation with sodium hypochlorite activated with XP-endo Finisher and the chlorhexidine groups to 2% (P<0.05).ConclusionsInterfacial bond strength and adaptation of SA cements used in this study were improved following addition of enamel/dentin etching step for a short time. This was not exceeded for longer times than 5-second. Key words:Dentin bond strength, enamel bond strength, pre-etching time, self-adhesive cement.

Antibacterial, physical and mechanical properties of bonding agent containing synthesized Zinc Dimethacrylate.

BackgroundThe aim of this study includes synthesis of zinc dimethacrylate ionomer (ZDMA) by a new method, incorporate it into resin bonding and evaluate its antibacterial, physical and mechanical properties.Material and MethodsResin adhesives containing 0 to 5% wt of ZDMA was produced and the following tests were accomplished: A: Antibacterial test: 1.Direct contact test. 2.Material aging; in both of them the bacterial colony counting were performed. B: Physical test: 1.Degree of conversion (D.C). 2.Evaluating the amount of released Zinc ion release in aqueous medium. C: Mechanical test: 1.Compressive strength test. 2.Shear bond test (enamel and dentine separately). The obtained results were statistically analyzed using One Way ANOVA and LSD post hoc test (α=0.05).ResultsThe anti-bacterial test revealed that all the ZDMA containing groups significantly reduced the amount of Streptococcus Mutans bacteria. Moreover, the D.C in all ZDMA groups was enhanced. Furthermore, ion release analysis revealed noticeable stability of Zn2+ in samples, as in the 5wt.% group it was even after nine cycle of 24h wash. On the other hand, the compressive strength was significantly reduced just in the 5% ZDMA group while the other groups were superior comparing to the control. In addition, there was no significant difference among the enamel shear bond strength of the groups. However, about the dentine shear bond strength, only the 5% ZDMA group was significantly higher than the control.ConclusionsLow percentages of ZDMA in adhesive could impart anti-bacterial efficacy without challenging its mechanical and physical properties. Key words:Dental Resin Bonding, Zinc, Streptococcus mutans, Degree of conversion, Compressive strength.

The roughness of deciduous dentin surface and shear bond strength of glass ionomers in the treatment with four minimally invasive techniques.

The concept of minimally invasive technique in dentistry emphasizes conservative strategies in the management of caries, which results in less destruction of healthy tooth structure. The use of different techniques seems to interfere in the roughness of dentin and the mechanisms of adhesion with the restorative material. This study characterized the roughness of deciduous dentin surface treated with four minimally invasive techniques using profilometry, atomic force microscopy (AFM) and scanning electron microscopy (SEM); moreover, shear bond strength of Vitremer™ glass ionomer was determined. Samples were divided into four groups: G1_CB carbide bur, G2_PB polymer bur, G3_C Carisolv™, and G4_AA air abrasive. No differences were found between groups before and after treatment in the roughness. Samples treated with a carbide bur presented a smear layer; smart bur surface exhibited the remains of the material; G3_C Carisolv™ showed a rough surface, and air abrasive presented particle traces. Concerning the shear bond strength of Vitremer™ glass ionomer were not found differences after treatment (p > 0.05). It is concluded that roughness showed characteristic patterns derived from the technique used and the shear bond strength is not significantly affected after using any minimally invasive method.

Effect of Er,Cr:YSGG on bond strength and microleakage of dentin bonded to resin composite with different distance and irradiation time.

To explore the surface modification of dentin using Er,Cr:YSGG phototherapy and bonding system on the shear bond strength and microleakage scores at two different distances and times of laser irradiation. Ninety disease-free third molars were collected for the experiment. The four laser groups were divided on the basis of non-contact mode distance and time of irradiation: Group-I: Distance of 1 mm with duration of 60 s; Group-II: Distance of 1 mm with duration of 120 s; Group-III: Distance of 2 mm with duration of 60 s and; Group-IV: Distance of 2 mm with duration of 120 s. The surface for control group (Group-EB: Etch & bond group) was treated with etch and rinse bonding regime. Specimens from all the groups were assessed for shear bond strength and microleakage scores. Samples from all groups were immersed in 2% methylene blue for 24 h and assessed under a digital microscope for microleakage. The lowest bond strength and microleakage was observed in the control group EB. The maximum bond strength score was observed in Group-IV with mean scores 23.41 ± 1.83, while the maximum microleakage scores were observed in Group-II and Group-IV with mean scores 1.0 ± 0.36 and 1.0 ± 0.11, respectively. The lowest bond strength and microleakage among laser groups was observed in Group-II and Group-III, respectively. However, specimens in laser groups showed comparable bond strength and microleakge scores (p > 0.05). For bond strength and microleakage values, analysis of variance showed significant difference among the study groups (p < 0.001). Using Tukey post hoc test, bond strength and microleakage of laser groups showed statistically significant values than EB group. Use of phototherapy using Er,Cr:YSGG for dentin surface treatment has the potential for clinical application in comparison to conventional conditioning technique. Increasing the distance of laser application and time of irradiation has significant effect on the shear bond strength and microleakage scores of dentin bonded to resin composite. However, further in-vitro analysis should be undertaken in order to prove such findings.

Protein-repelling adhesive resin containing calcium phosphate nanoparticles with repeated ion-recharge and re-releases

ObjectivesThe objectives were to develop a calcium (Ca) and phosphate (P) ion-rechargeable and protein-repellent adhesive containing nanoparticles of amorphous calcium phosphate (NACP) and 2-methacryloyloxyethyl phosphorylcholine (MPC), and investigate the MPC effects on ion recharge and re-releases for the first time. MethodsPyromellitic glycerol dimethacrylate and ethoxylated bisphenol-A dimethacrylate were used to fabricate adhesive PEHB. Six adhesives were tested: (1) Scotchbond (SBMP); (2) PEHB, (3) PEHB + 20%NACP; (4) PEHB + 30%NACP; (5) PEHB + 20%NACP+3%MPC; (6) PEHB + 30%NACP+3%MPC. Dentin shear bond strength, Ca/P ion release, recharge and re-release, and protein adsorption were measured. A microcosm biofilm model was tested for lactic-acid production and colony-forming units (CFU). ResultsAdding NACP + MPC did not negatively affect dentin bond strength (p > 0.1). With increasing the number of recharge/re-release cycles, the Ca/P ion re-release reached similarly higher levels (p > 0.1), indicating long-term remineralization capability. One recharge enabled the adhesives to have continued re-releases for 21 days. Incorporation of 3% MPC yielded 10-fold decrease in protein adsorption, and 1–2 log decrease in biofilm CFU. ConclusionsThe new rechargeable adhesive with MPC + 30%NACP greatly reduced protein adsorption, biofilm growth and lactic acid. Incorporation of MPC did not compromise the excellent Ca/P ion release, rechargeability, and dentin bond strength. Clinical significanceNovel bioactive adhesive containing MPC + NACP is promising to repel proteins and bacteria, and inhibit secondary caries at the restoration margins. The method of NACP + MPC to combine CaP-recharge and protein-repellency is applicable to the development of a new generation of materials including composites and cements to suppress oral biofilms and plaque formation and protect tooth structures.