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The present study assessed the effect of active application of self-etch adhesives with diode laser irradiation on the shear dentin bond strength. Sixty bovine incisors, each embedded individually in hard plaster blocks, were divided into two groups based on the adhesive system used: Group 1 Adper Easy One and Group 2 Clearfil SE Protect. Based on the application technique of self-etch adhesives, each main group was further divided into three subgroups: passive application, active application with a micro-brush, and active application with a 976-nm diode laser tip (phototherapy active application). Shear bond strength tests were conducted using a universal testing machine and the data were analyzed by two-way ANOVA. Post hoc multiple comparisons were performed with the Tukey HSD test. Additionally, the statistical analysis of failure mode distribution was carried out using the chi-squared test (p < 0.05). While the adhesive system exhibited significant differences in shear dentin bond strengths, there were no significant differences in application techniques. Regardless of the application technique, Clearfil SE Protect demonstrated significantly higher dentin bond strength than Adper Easy One. In the present study, the utilization of phototherapy through a 976-nm diode laser for the active application of the tested self-etch adhesives demonstrated similar initial dentin bond strengths to conventional application methods.

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The objectives of this study were to evaluate the bonding durability of four different self-etch adhesives to dentin after 24 h and thermal cycling (TC) and to measure the degree of polymerization conversion (DC) in situ. Two-step self-etch adhesives, Clearfil SE Bond 2 (SE2, Kuraray Noritake Dental) and G2-Bond Universal (G2B, GC), and one-step self-etch adhesives, Scotchbond™ Universal Plus Adhesive (SBU, 3M ESPE) and Clearfil Universal Bond Quick (UBQ, Kuraray Noritake Dental), were used. The labial surfaces of bovine teeth were ground to create flat dentin surfaces. The adhesives were applied according to the manufacturers' instructions. After resin composite buildup and 24 h water storage, the specimens were sectioned into beams and all groups were subjected to thermal stress for 0, 10,000 (10k), or 20,000 (20k) cycles followed by micro-tensile bond strength (µTBS) testing. In situ DC was investigated with a laser Raman microscope. The µTBS data were statistically analyzed and subjected to a Weibull analysis. The different groups were compared at the characteristic strength (63.2% probability of failure) (α = 0.05). Two-Way ANOVA was used to show the effect of different adhesives and thermal cycling on the mean DC% followed by Tukey's multiple comparison post hoc test. G2B/TC10k resulted in a significant increase in the µTBS compared to TC0. SBU/TC20k showed significantly higher µTBS compared to TC0. For comparison between different tested adhesives, SBU showed a significantly lower µTBS compared to G2B after TC10k. G2B and SBU showed a greater number of adhesive failures after TC. Mean DC% was different for each adhesive. The newly developed MDP- and HEMA-free 2-SEA showed similar bonding performance with the gold-standard 2-SEA. However, there is still room for further improvement in terms of SEAs.

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Evaluation of micro tensile bond strength (µTBS) and marginal leakage of sodium fluoride (NaF) and nano-hydroxyapatite (n-HA) modified universal adhesives (UAs) bonded using etch-and-rinse (ER) and self-etch (SE) bonding technique to the carious affected dentin (CAD). One hundred and twenty primary molars were prepared for CAD on the occlusal surface. The occlusal CAD surface was flattened and underwent a polishing procedure. The specimens were divided into six groups using a random allocation method based on the UAs applied and the mode of etching used (n = 20) Group A1: UAs (ER), Group B1: UAs (SE), Group A2: UAs (NaF) + ER, Group B2: UAs (NaF) + SE, Group A3: UA (n-HA) + ER and Group B3: UAs (n-HA) + SE. Composite restoration was placed and samples were thermocycled. Microleakage, µTBS, and failure mode assessment were performed using a dye penetration test, universal testing equipment, and stereomicroscope respectively. The µTBS and microleakage results (mean ± SD) were examined using analysis of the variance (ANOVA) and Tukey post hoc tests. Group B1 (UAs + SE) demonstrated the maximum scores of microleakage (25.14 ± 9.12 nm) and minimum recorded value of µTBS (14.16 ± 0.55 MPa). In contrast, Group A3 (UAs (n-HA) + ER) displayed a minimum value of marginal leakage (12.32 ± 6.33 nm) and maximum µTBS scores (19.22 ± 0.92 MPa). The outcomes of the intergroup comparison analysis showed that Group A2 (UAs (NaF) + ER), Group B2 (UAs (NaF) + SE), Group A3 (UA (n-HA) + ER) and Group B3 (UAs (n-HA) + SE) presented comparable outcomes of marginal seal outcomes and µTBS scores (p > 0.05). NaF and n-HA-modified UAs displayed favorable bond strength and minimum marginal leakage to the deciduous affected dentin surface.

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Objective: The objective of the study was to assess the shear bond strength of bulk-fill flowable composite resin smart dentin replacement plus when bonded to mineral trioxide aggregate (MTA)-angelus, biodentine, and calcium-enriched mixture (CEM) at two different aging periods (15 min and 72 h) using three distinct adhesive systems. In addition, the study identified the specific modes of failure (adhesive, cohesive, or mixed) using a stereomicroscope and scanning electron microscope. Materials and Methods: One hundred and twenty-six cylindrical acrylic blocks used in the study were sorted into three groups based on the bioactive substance used to fill the 3-mm diameter and 3-mm high hole in the center of each block. The groups were MTA, Biodentine, and CEM. The specimens were then divided into subgroups based on the aging interval (15 min and 72 h) of the bioactive material and the adhesive system used (two-step total-etch, two-step self-etch [SE], and one-step SE) while bonding to the restorative bulk-fill flowable composite. The shear bond strength values were measured with a universal testing machine, and the data were analyzed using two-way and one-way analysis of variance, followed by a post hoc test. The specimens were assessed under stereomicroscope and scanning electron microscope to characterize the mode of bond failure (cohesive, adhesive, or mixed). Results: The study showed that the type of adhesive system and the time of bonding affected the shear bond strength of bulk-fill composite to the pulp capping agents (P < 0.05). For MTA, the highest bond strength was observed with two-step SE group at 15 min (18.16 ± 2.97 MPa) (P < 0.05). CEM exhibited the highest bond strength with two-step SE group at 72 h intervals (8.77 ± 1.76) (P < 0.05). The highest bond strength for biodentine group was observed with total-etch group (8.54 ± 1.35 Mpa) and two-step SE (8.19 ± 1.94 Mpa) bonded at 72 h interval (P < 0.05). The majority of the samples in the MTA group (29/42) and CEM group (20/42) showed a cohesive fracture, whereas Biodentine group (22/42) had an adhesive fracture in most of its samples. Conclusion: MTA demonstrated the highest bond strength with two-step SE group at 15 min, and CEM exhibited the highest bond strength with two-step SE groups at 72 h interval. For biodentine group, the type of adhesive used did not impact the bond strength values.

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Objective: This work aimed to assess the bonding performance of universal adhesive and self-etch adhesives, and a comparative study was conducted using the same acid etching mode. Methods: The selective acid-etching mode was used to simulate bonded restorations to teeth defects of isolated human molars including enamel and dentin. Microtensile bond strength and microleakage of all adhesives were tested and compared after 24 h and 5000 thermocycles, respectively. The morphology of the adhesive interfaces was observed by scanning electron microscopy (SEM) and fluorescent staining. Results: The bond strength and microleakage of Single Bond Universal (SBU) adhesive are comparable to those of self-etch adhesives, although Clearfil Tri-S Bond (S3) exhibited significantly lower bond strength compared to other two self-etch groups evaluated. No significant differences were found in the microleakage resistance of these four adhesives, suggesting their similar effectiveness in sealing the margins of the restorations, although SBU showed the highest resistance of microleakage. The SEM and fluorescent staining results of the resin-dentin interfaces further revealed the formation of abundant resin tags for all adhesives. Conclusions: Self-etch adhesives evaluated in this study performed similarly to universal adhesives in selective acid-etch mode for bond strength and microleakage resistance. Both types of adhesives exhibited effective penetration capabilities into the dentinal tubules. Clinical significance: During the adhesion processes involving both dentin and enamel, self-etch adhesives can serve as alternatives to universal adhesives in selective acid-etch mode.

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Aims: To evaluate hydroxyapatite-silver (HA-Ag) hybrid nanoparticles (NPs), as an antibacterial agent when integrated in self-etch (SE) adhesive. Blue light activated HA-Ag hybrid NP incorporation on mechanical properties, degree of conversion (DC), and microtensile bond strength (µTBS). Method: Eighty primary molar teeth have carious lesions reaching the dentin but not involving the pulp. The infected dentin was removed and carious-affected dentin (CAD) was preserved. Forty samples were inoculated with Streptococcus mutans. All primary teeth (n = 80) were allocated into four groups based on the incorporation of HA-Ag hybrid NPs in different concentrations (0%, 1%, 5%, and 10%). Group 1: 0% HA-Ag hybrid NPs + Clearfil SE bond primer, group 2: 1% HA-Ag hybrid NPs + Clearfil SE bond primer, group 3: 5 wt% HA-Ag NPs + Clearfil SE bond primer, and group 4: 10 wt% HA-Ag NPs + Clearfil SE bond primer. The survival rate assessment of S. mutans was conducted on 40 inoculated samples. On the remaining primary teeth (n = 40), Clearfil SE bonding agent was applied uniformly via a blue light source. The composite buildup was performed on the samples and µTBS and failure analysis assessed. Fourier transform infrared spectroscopy was performed to assess DC. Survival rates of S. mutans and µTBS among the tested groups were compared using ANOVA and Tukey post hoc analysis. Results: 10 wt % HA-Ag NPs + Clearfil SE bond primer exhibited the highest level of antibacterial efficacy (0.14 ± 0.02 CFU/mL) against S. mutans. The highest µTBS (18.38 ± 0.78 MPa) at the composite/CAD interface was in group 2 (1 wt % HA-Ag NPs + Clearfil SE bond primer + Clearfil SE bonding agent + activation with a blue light source). The highest DC was observed in the control group with Clearfil SE bond primer + Clearfil SE bonding agent + activation with a blue light source. Conclusion: 1 wt% HA-Ag hybrid NPs showed enhanced antibacterial effectiveness, DC, and bond strength of the SE adhesive to the primary CAD.

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Background: This retrospective clinical study aimed to assess dental pulp tissue reactions to direct and indirect pulp capping after 10 years of follow-up. Methods: A total of 276 permanent teeth with deep carious lesions were evaluated and divided into five groups: Group (1), direct pulp capping with Mineral Trioxide Aggregate cement; Group (2), direct pulp capping with a resin-based glass ionomer; Group (3), direct pulp capping with TheraCal; Group (4), indirect pulp capping with a three-step total-etch adhesive system; and Group (5), indirect pulp capping with a two-step self-etch adhesive system. Results: A 72.5% success rate was achieved overall. A statistically significant difference was found when comparing direct and indirect pulp capping with a success rate of 23.8% and 93.8%, respectively. For direct pulp-capping procedures, the area of pulp exposure was correlated with pulp necrosis (p = 0.035), while bleeding after exposure appeared independent (p = 0.053). Patient age was significantly related to the maintenance of pulp vitality (p = 0.013). A statistically significant correlation between the pulp-capping material and the occurrence of pulp necrosis was discovered (p = 0.017). For the indirect pulp-capping treatments, a significant correlation between patient age (p = 0.021) and the adhesive system (p = 0.019) with pulp necrosis was described. Conclusions: The pulp-capping material, patient age, and the width of the pulp exposure before the procedure should be carefully considered when performing direct pulp-capping treatments. The performance of the etch-and-rinse adhesive systems was superior to the self-etch system during the indirect pulp-capping procedures.

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Background and objective: The aim of this randomized split-mouth study-controlled clinical trial was to compare the 2-year clinical performance of resin composite restorations placed at non-caries cervical lesions (NCCL) with one-step self-etch, total-etch, and selective enamel etch and self-etch adhesive techniques. Materials and methods: Thirty-two patients received three resin composite restorations each at NCCLs (Tetric EvoCeram/Ivoclar/Vivadent), bonded with a total-etch adhesive agent (ExciTE F/Ivoclar/Vivadent) and a self-etch (AdheSE One F/Ivoclar/Vivadent) without and with selective enamel etching. All restorations were evaluated by two examiners at baseline, 6-, 12-, 18-, and 24-months with FDI clinical criteria (post-operation regarding retention, caries occurrence, marginal adaptation, and marginal staining). A logistic regression analysis, a Cohen's kappa statistic, a multifactorial analysis, and X2 were performed with generalized estimating equations. Results: After 2 years, the retention rate was 86.8% for total etch, 92.26% for self-etch, and 93.63% for selective enamel etching and self-etch. No caries was detected on the restorations. Concerning marginal adaptation, the clinically perfect restorations were 26.9% for the total-etch technique, 16% for self-etch, and 25.9% for selective enamel etch and self-etch. The logistic regression model revealed that only time reduced the probability of perfect marginal adaptation. Conclusions: All three adhesive strategies provided restorations with no significant differences in the retention rate or marginal adaptation, whereas the total etch yielded better performance for marginal staining. All restorations were assessed as clinically acceptable after 2 years.

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Aim: In this, in vitro study's objective is to assess the shear bond strength (SBS) of metal and ceramic orthodontic brackets that have been adhered to enamel using a conventional acid etch/primer and self-etching primer (SEP) adhesive method. Materials and Methods: One hundred excised human premolars were bonded on brackets and were divided into group 1 -Metal brackets were bonded on teeth and group 2 -Ceramic brackets were bonded on teeth. These two groups were further subdivided: subgroup 1a - 25 metal brackets bonded using conventional acid etch/primer adhesive system, subgroup 1b - 25 metal brackets bonded using SEP, subgroup 2a - 25 ceramic brackets bonded using conventional acid etch/primer adhesive system, and subgroup 2b - 25 ceramic brackets bonded using SEP; brackets were debonded using a computerized Instron universal testing machine. Results: The mean value of SBS of metal and ceramic brackets bonded using conventional acid etch/primer adhesive systems had higher SBS than those bonded using SEP. SBS ranged from 7.95 to 12.24 MPa which was in the acceptable clinical range. Conclusion: SBS values of all four subgroups exceeded the range of 6-8 MPa observed to be acceptable for routine clinical use.

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AIM: To compare the shear bond strength and penetration ability of self-etch sealant with and without enamel deproteinization. MATERIALS AND METHODS: A total of 37 sound extracted teeth were selected and 31 teeth were used for testing shear bond strength of self-etch sealant. For this, crowns portions of selected teeth were cut longitudinally with a diamond disc into a mesial and distal half, thereby yielding 62 samples. They were further divided into two groups; in Group 1, samples were deproteinised with 5.25% sodium hypochlorite and a sealant cylinder was built on the proximal surface. In Group 2, sealant cylinders were built without deproteinising the surface. Shear bond strength was tested using Universal Testing Machine. The remaining six teeth were used for penetration evaluation of self-etch sealant. In Group 1, the occlusal surface was deproteinised with 5.25% sodium hypochlorite and self-etch sealant was directly applied. In Group 2, sealant was applied without deproteinisation. The samples obtained after sectioning were observed under scanning electron microscope for sealant penetration. Mann-Whitney test and Chi-square analysis were utilised for statistical analysis. RESULTS: The results showed that the shear bond strength of the two groups was statistically not significant (p = 0.23). However, the comparison of % penetration revealed a statistically significant difference between the groups (p = 0.016). CONCLUSION: Deproteinising the enamel surface prior to application of self-etch sealant enhanced the penetration ability of the sealant but did not show any effect on shear bond strength.

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AIM: The aim of this study was to compare the microtensile bond strength (µTBS) and failure mode of 4 different universal adhesive systems (UAs) on human dentin. MATERIALS AND METHODS: The study sectioned the occlusal thirds of 32 human third molars and divided them into 4 groups based on the adhesive system used. Group A: Palfique Universal Bond, Group B: Single Bond Universal, Group C: All-Bond Universal, and Group D: One Coat 7 Universal. The specimens underwent a 10,000-cycle thermocycling ageing process prior to testing (n = 32). Afterwards, 8 beams were obtained per group and subjected to µTBS testing using a digital universal testing machine at a speed of 1 mm/min. The microtensile bond strength values were analysed in Megapascals (MPa), and the failure mode was evaluated using a stereomicroscope. Welch's parametric ANOVA with robust variance and the Games-Howell post hoc test were used for µTBS comparisons, and Fisher's exact test was used to determine the association between adhesive type and failure mode. The significance level was set at P < .05. RESULTS: Group D showed a significantly higher µTBS than groups A (P < .001) and B (P < .001), but no significant difference was observed with group C (P= .075). Furthermore, groups B and C showed significantly higher µTBS than group A (P< .001 and P < .001, respectively), but there was no significant difference between groups B and C (P = .132). Additionally, group A exhibited a significant association with an adhesive failure mode (P < .05), whereas groups B, C, and D were significantly associated with a mixed failure mode (P < .05). CONCLUSION: The One Coat 7 Universal adhesive system showed higher microtensile bond strength values and higher chemical interaction with dentin compared to Palfique Universal Bond and Single Bond Universal. However, no significant differences were observed compared to All-Bond Universal.

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Objective This study aims to analyze three different bonding protocol strategies in determining the fracture resistance on the reattachment of fragments in permanent anterior teeth. Methodology This study evaluated the ability of three bonding methods (Group A, total-etch technique; Group B, selective-etch technique; and Group C, self-etch technique) to enhance the fracture resistance of reattached tooth fragments. Sixty permanent maxillary central incisors were chosen, segmented at 3 mm from the incisal edge, and randomly distributed among the three groups. Tooth fragments were stored for 24 hours in GC Tooth Mousse (GC Corporation, Tokyo, Japan), and then reattachment was done using respective bonding techniques. Fracture resistance was gauged using a universal testing machine. Results The mean fracture resistance values were as follows: total-etch (419.5995 N), selective-etch (359.1448 N), and self-etch (192.0887 N). One-way analysis of variance (ANOVA) and post hoc Tukey tests revealed a statistically significant difference between the groups. It was inferred that the total-etch technique exhibited the highest fracture resistance, while the self-etch technique resulted in the lowest fracture resistance (P < 0.05). Conclusions The choice of bonding technique for reattaching tooth fragments should be made based on clinical context and patient needs. Total-etch provided the highest fracture resistance, but selective etch can be preferred for anterior teeth with lower occlusal loads to prevent sensitivity. The self-etch technique may not provide sufficient strength and should be used cautiously. More clinical studies are required to validate these findings and guide clinical decision-making in traumatic dental injury management.

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This study aimed to evaluate internal tooth-filling interfaces of composite fillings made using universal adhesives using micro-computed tomography (µCT). Sixty class V cavities were randomly assigned into six groups: Peak Universal etch and rinse (PER), Peak Universal self-etch (PSE), Adhese Universal etch and rinse (AER), and Adhese Universal self-etch (ASE). Two further adhesives considered gold standards were used as control groups: OptiBond FL (OER) for the etch and rinse technique and Clearfil SE for the self-etch technique (CSE). All teeth were subjected to thermomechanical loading and four-year water storage. Next, they were analyzed using µCT to investigate the internal tooth-filling interfaces. The proportions between the gap volume (GV) at the tooth-filling interface and the volume of applied composite filling (FV), between the gap and cavity volumes (CV), and between the gap volumes at the tooth-filling interface of the external (EGV) and internal (IGV) parts were calculated. Adhese Universal achieved the significantly lowest gap-to-filling- and gap-to-cavity-volume ratios for both types of etching techniques comparing to those of the Peak Universal and control groups. Significant differences between the gaps in external and internal parts of the tooth-filling interface were only noted in the control groups. Internal gap formation and development at the tooth-filling interface depend on the material as well as the type of its application.

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INTRODUCTION: The aim of this in vitro study was to compare the quality of marginal sealing at the cervical margins of indirect and direct composite resin restorations in mesio-occluso-distal (MOD) cavities. MATERIAL AND METHOD: MOD preparations were performed on 30 extracted teeth. The mesial cervical margin of each tooth was relocated using a flow composite resin (Enamel Plus HRi Flow, Micerium, Avegno, GE, Italy), then the samples were divided into three groups. In group A, the cavities were directly restored using a nanohybrid composite resin (Miris 2 Coltène Whaledent, Altstaetten, Switzerland) and a universal adhesive (ScotchBond Universal, 3M ESPE, St. Paul, MN, USA) by the etch-and-rinse strategy, for group B, the restoration procedure was similar but the self-etch strategy was used, and the samples in group C were filled using the inlay technique. Each sample was stored for 48 h in a 2% methylene blue solution, then it was cut in a mesio-distal direction using a Struers Secotom 50 device (Cleveland, OH, USA). The marginal sealing and adhesive interface were assessed for each sample at the cervical margin by optical microscopy (OM) and scanning electron microscopy (SEM). One-way ANOVA and Bonferroni post-hoc tests were used with a significance level of 0.05. RESULTS: Significant differences were recorded within groups A and C, between mesial and distal margins (p = 0.02 in group A and p = 0.043 in group C). CONCLUSIONS: The marginal sealing is more effective in MOD inlay restoration compared to direct restorations. Relocation of the cervical margin with flow composite resin and the use of different adhesive strategies do not improve the marginal sealing.

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The aim of this study was to systematically compare the bond strength of self-adhesive and self-etch or total-etch resin cement to zirconia. The PubMed, ISI (all), and Scopus databases were searched for the selected keywords up to November 1, 2021, without date or language restrictions. In vitro studies comparing the bond strength of self-adhesive and self-etch or total-etch resin cement to zirconia were eligible for inclusion in the study. The selected articles were divided into four groups based on the type of resin cement and the storage time. Statistical analysis was performed using the Biostat Comprehensive Meta-Analysis Software version 2 (α = 0.05). The effect of conventional cement ( Glass Ionomer (GI), Resin Modified Glass Ionomer (RMGI) and zinc phosphate) was analyzed using descriptive analysis. The initial search yielded 376 articles, of which 26 were selected after a methodological assessment. Two reviewers independently extracted data and assessed the risk of bias. The results showed that the immediate or delay bond strength of the self-adhesive resin cement to zirconia has no significant difference with the bond strength of self-etch resin cement to zirconia. The immediate and delay bond strength of total-etch cement-zirconia was significantly lower than that of self-adhesive cement-zirconia (P = 0.00). A descriptive analysis of the selected articles showed that the bond strength of self-adhesive resin cement to zirconia was significantly higher than total-etch cement. The results of the meta-analysis showed that both self-adhesive and self-etch resin cement (if applied according to their manufacturer's instruction) are suitable for bonding to zirconia.

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OBJECTIVES: To examine whether dentin-etching extension and/or the hydrophobic-rich content of hybrid layers would affect fatigue strengths of a mild universal adhesive after long-term aging. METHODS: Twin-bonded resin-dentin interfaces were produced by etching sound midcoronal dentin beams with 32 % ortho-phosphoric acid for 15 s (OPA15s), 3 s (OPA3s) or 10 % meta-phosphoric acid for 15 s (MPA15s). Samples were bonded with a mild universal adhesive with or without additional coating using a solvent-free bisGMA-based bonding resin. Self-etch application served as control. Composite buildups were made with a nanofilled composite. Bar-shaped twin-bonded interfaces (0.9 × 0.9 × 12 mm) were aged for two years in artificial saliva at 37 â„ƒ and tested under 4-point flexure at quasi-static (n = 16) and cyclic loads (n = 35) until failure. The stress-life fatigue behavior was evaluated using the staircase method at 4 Hz. Crack initiation and fracture patterns were evaluated by SEM. Cyclic-loaded data was analyzed by Kruskal-Wallis on Ranks (α = 0.05). RESULTS: Significantly higher fatigue life distributions and higher endurance limits were observed for less aggressive etch-and-rinse protocols (OPA3s and MPA15s) after long-term ageing. Hydrophobic-rich coating produced 20-32 % higher endurance limits, prevented micrometer-sized porosities at bonded interfaces, reduced etching-associated variability and lowered crack formation. Significance Long-term hydrolysis produces detrimental effects on the fatigue strength of resin-dentin interfaces. The bond-promotion effect of less aggressive etch-and-rinse protocols and the creation of hybrid layers with higher hydrophobic-rich content are critical to extend the durability of mild universal adhesives. Therefore, current oversimplification trends in adhesive dentistry may limit resin-dentin bonding performance.

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OBJECTIVES: Extrafibrillar demineralization is an etching technique that removes only minerals from around the collagen fibrils for resin infiltration. The intrafibrillar minerals are left intact to avoid their replacement by water that is hard for adhesive resin monomers to displace. The present work reported the synthesis of a water-soluble methacryloyloxy glycol chitosan-EDTA conjugate (GCE-MA) and evaluated its potential as an extrafibrillar demineralization agent for self-etch dentin bonding. METHODS: Glycol chitosan-EDTA was functionalized with a methacryloyloxy functionality. Conjugation was confirmed using Fourier transform-infrared spectroscopy. The GCE-MA was used to prepare experimental self-etch primers. Extrafibrillar demineralization of the primers was evaluated with scaning electron microscopy and transmission electron microscopy. The feasibility of this new self-etch bonding approach was evaluated using microtensile bond strength testing and inhibition of dentin gelatinolytic activity. The antibacterial activity and cytotoxicity of GCE-MA were also analyzed. RESULTS: Conjugation of EDTA and the methacryloyloxy functionality to glycol chitosan was successful. The functionalized conjugate was capable of extrafibrillar demineralization of mineralized collagen fibrils. Tensile bond strength of the experimental self-etch primer to dentin was comparable to that of phosphoric acid-etched dentin and the commercial self-etch primer Clearfil SE Bond 2. The GCE-MA also inhibited soluble rhMMP-9. In-situ zymography detected minimal fluorescence in hybrid layers conditioned with the experimental primer. The GCE-MA was noncytotoxic and possessed antibacterial activities against planktonic bacteria. SIGNIFICANCE: Synthesis of GCE-MA brought into fruition a self-etch conditioner that selectively demineralizes the extrafibrillar mineral component of dentin. A self-etch primer prepared with GCE-MA achieved bond strengths comparable to commercial reference adhesive systems.

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Red-fluorescing dentine indicates bacterial contamination [Caries Res 2002; 36: 315-319]. We investigated effect of removal of red fluorescent dentine caries on shear bond strength and fracture mode of 4 adhesive approaches. Sixty-five carious teeth and 50 noncarious controls were distributed into 4 groups: Clearfil™ self-etch (CSE), OptiBond™ FL total etch (OTE), Scotchbond™ Universal total etch (STE) and self-etch (SSE). Samples were excited at 405 nm and viewed through 530 nm filter. Carious samples were ground flat exposing strongly red-fluorescing (StrongRF) dentine, on which a composite cylinder was placed, using one of 4 adhesives. After 22 h in water, shear bond strength and fracture mode were analysed. StrongRF was removed; composite cylinders were placed on weakly red-fluorescing (WeakRF) dentine and tested as described above. Finally, red-fluorescing dentine was removed, and composite cylinders were placed on non-fluorescing (NonRF) dentine and tested. Composites were placed at 3 corresponding heights in controls. After 22 h in water, shear bond strength testing and fracture mode analysis were performed. Differences were tested using Mann-Whitney or Wilcoxon tests (p ≤0.05). Median (Q1, Q3) shear bond strength on StrongRF was SSE 14.4 (9.2, 18.2) MPa >CSE 10.2 (6.4, 17.3) MPa >STE 9.1 (6.9, 11.2) MPa >OTE 6.8 (4.0, 10.8) MPa. Shear bond strength increased statistically significantly for all adhesives on WeakRF: SSE 19.8 (13.6, 24.3) MPa >STE 19.5 (12.7, 23.1) MPa >CSE 17.5 (12.0, 22.5) MPa >OTE 15.8 (11.9, 20.9) MPa. Only STE 25.6 (22.4, 29.1) MPa and CSE 22.1 (17.6, 24.6) MPa were significantly different on NonRF compared to WeakRF. For controls tested at corresponding depths, superficial shear bond strength was OTE 18.7 (16.0, 22.1) MPa >STE 18.4 (12.0, 25.9) MPa >CSE 18.1 (12.7, 20.7) MPa >SSE 13.0 (9.6, 17.8) MPa. This was significantly higher compared to StrongRF except for SSE. Central shear bond strength was not significantly different to WeakRF, deep shear bond strength was significantly lower for SSE and CSE but higher for OTE compared to carious. Conclusion: StrongRF dentine should be removed for higher shear bond strength, but WeakRF dentine can often be preserved without compromising adhesive bond strength.

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Background: Self-adhering composites are claimed to bond to teeth without prior acid etching and bonding steps. This study aimed to evaluate the cyclic shear fatigue (CSF) of metal orthodontic brackets bonded to enamel using self-adhering flowable composites (Constic and VertiseTM Flow) in comparison with that of total-etch and self-etch adhesives. Materials and methods: Twenty-five human premolars comprising 100 surfaces were randomly divided into four groups (n = 25): total-etch, self-etch, Constic, and VertiseTM Flow. A total of 10 surfaces were used per group for baseline static shear bond strength (SSBS) evaluation and 15 surfaces for CSF evaluation. Each tooth was treated with the four bonding agents. Both SSBS and CSF were evaluated using a universal testing machine. For CSF, the staircase method was used with an initial pulling load equivalent to 60% of the SSBS of each group for 1000 cycles or until failure. The adhesive remaining index (ARI) was evaluated for surviving samples using a stereomicroscope. Statistical analysis: A one-way ANOVA with Tukey's post hoc test was used to analyze the CSF data, and a chi-square test was used to analyze the ARI. Results: The total-etch adhesive showed significantly higher CSF values than that of the other groups (p < 0.001). Both total-etch (10.78 ± 0.31 MPa) and self-etch (6.75 ± 0.91 MPa) adhesives showed significantly higher CSF than did Constic (1.94 ± 0.31 MPa) and VertiseTM Flow (2.01 ± 0.25 MPa), (p < 0.001). The ARI indicated that more resin remnants were observed with the total-etch and self-etch adhesives than those with the self-adhering flowable composites. However, no significant differences were observed among groups (p > 0.05). Conclusions: Total-etch and self-etch adhesives showed satisfactory bond strengths for orthodontic treatment. However, Constic and VertiseTM Flow self-adhering flowable composites may not be clinically sufficient for bonding metallic orthodontic brackets to enamel.

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The goal of this article was to assess the effect of modified triple-layer application (MTLA) in conjunction with the active bonding technique on the bond strength of four adhesive systems to dentinal substrate. The adhesives tested were Prime&Bond Universal (PBU), OptiBond Universal (OBU), OptiBond FL (OBFL), and Clearfil SE (CSE). The adhesives were applied according to the following strategies: single active application (A) and triple adhesive layer application including Active-Passive-Passive (APP); AAP; and AAA. The micro-tensile bond strength test was evaluated following 24 h or 6 months of storage. The composite-dentin interface morphology was investigated using scanning electron microscopy. The data were statistically analyzed with a significance level of α = 0.05. At 24 h of aging, all of the factors tested were not significant (p > 0.05) for CSE. For OBFL, OBU, and PBU, statistically higher values were observed for the A technique (p < 0.05). Plus, there were no significant variances between the APP, AAP, and AAA techniques (p > 0.05) for OBFL and PBU. However, for OBU, there were no significant differences between the A and AAA techniques (p > 0.05). After 6 months of aging, the A technique showed statistically higher values when compared to the other techniques (p < 0.01), except for OBFL, where the A and AAA techniques showed promising outcomes. When comparing the bond strength values of 24 h and 6 months, only for PBU, all of the techniques used resulted in bond strength stability over time (p > 0.05). Thicker adhesive layers were observed when MTLA was applied. Only the OBFL adhesive showed the formation of resin tags in all of the modalities tested. The bonding performances of the different application techniques used were material-dependent.