Universal Adhesives Research Articles

Does different application modes of universal adhesives with universal resin composites affect the microleakage in class V cavities? An in vitro study.

Composite restorations often have gingival margins near the cemento-enamel junction (CEJ), where the microleakage of these margins can significantly contribute to the restoration failure, especially in the cervical lesions. It is important to determine the microleakage is crucial, as it typically occurs through the interfacial gap between the tooth and the restoration. Various resin composites and techniques have been developed to minimize this gap and reduce the risk of microleakage. The aim of this in vitro study was to evaluate the levels of microleakage of different modes of a universal adhesive and two novel resin composites in restoring class V cavities in the central incisors. Sixty-six freshly extracted sound human central incisors of the similar size were randomly assigned to 2 groups (n = 33 per group) according to the brand of resin composite. Each group was further divided into 3 subgroups based on the Scotch Bond Universal (3M ESPE, Saint Paul, MN, USA) application protocol used: (a) total etch, (b) self-etch and (c) selective etch. After composite restoration completed with Omnichroma (Tokuyama Dental Corp., Tokyo, Japan) and Filtek Universal Restorative (3M ESPE, Saint Paul, MN, USA), each tooth was immersed in a 0.5% basic fuchsin dye solution at 37C0 for 24h. After dye penetration, teeth were sectioned and evaluated with conventional (scoring) and digital methods (ImageJ). The intra- and inter-examiner agreement was estimated according to the Kappa statistics and the results were analyzed with the one-way ANNOVA and the Kruskal-Wallis test (p < 0.05). The rates of microleakage of the gingival and incisal margins are statistically similar, regardless of the composite brand and the method of application of the universal adhesive. The microleakage exhibited by current adhesives and resins is independent of the adhesive application mode and measurement method.

Exploring Dentists’ Preferences in Selecting Adhesive Systems: A Survey Analysis

Dental adhesives play a crucial role in modern dentistry by enabling the bonding of diverse restorative materials to tooth surfaces. These systems have evolved through seven generations, each characterized by unique chemical compositions and application techniques. The advancements in dental adhesives have significantly impacted restorative dentistry by preserving tooth structure, enhancing aesthetics, and ultimately improving patient outcomes and treatment options. The choice of adhesive system depends on various factors, including the clinical scenario, material compatibility, and dentist preference. Ongoing advancements in adhesive technology continue to enhance treatment outcomes and streamline procedures for dental practitioners. The development of universal adhesives capable of functioning in both etch-and-rinse and self-etch modes has further simplified clinical protocols. This study is an observational cross-sectional study conducted among Romanian dentists. A questionnaire was distributed via email to Romanian dentists, encompassing seven questions that explored the predominant use of etch-and-rinse or self-etch adhesive systems, preferred adhesive types, and commonly encountered challenges in direct restorations. Statistical analyses were conducted using DATAtab version (2024). The study highlighted the varying preferences among Romanian dentists in selecting suitable adhesive agents. Etch-and-rinse (ER) techniques predominated in direct restorations, with universal adhesives being the most frequently used. Further investigation is warranted to delve into the preferences of Romanian dentists regarding the utilization of self-etch (SE), etch-and-rinse (ER), and universal adhesives (UAs).

Assessment of clinical performance of universal adhesives versus other adhesive systems: A systematic review and meta-analysis of clinical trials

Universal adhesives (UAs) often exhibit comparable or even superior bond strength to traditional adhesive systems, ensuring reliable and long-lasting adhesion between the resin composite and the tooth structure. Therefore, this study aimed to assess the clinical performance of UAs compared to other adhesive systems in direct resin composite restorations through a systematic review and meta-analysis. Two reviewers executed a literature search in five electronic databases: PubMed, EMBASE, Scopus, Web of Science, and Scielo. Clinical trials comparing the clinical evaluation of resin composite restorations in Class I, Class II, or Class V cavities placed with an universal adhesive (UA) system against resin composite restorations placed with another non-UA system were included in the review. An analysis was carried out using Review Manager software version 5.3.5 (London, England, United Kingdom). Standardized effect sizes with 95% confidence intervals were calculated to allow comparisons between different interventions and different outcomes. The methodological quality of each study was assessed using the Cochrane RoB2 tool for randomized clinical trials. A total of 2331 potentially relevant studies were identified. After title and abstract examination, 14 studies remained in the systematic review. From these, a total of 11 studies were included in the meta-analysis. The retention rates of resin composite restorations after 6 months showed no significant difference between total-etch (TE, p=0.83), or self-etch (SE, p=0.78) adhesives and UAs applied in TE and SE modes (p&gt;0.05). However, UAs applied in selective-enamel etching (SEE) mode demonstrated superior clinical performance compared to other adhesives (p=0.01), particularly TE adhesives (p=0.02). Similarly, after &gt;12 months of follow-up, there were no significant differences in retention rates among different adhesive modes (p&gt;0.05). Additionally, the incidence of secondary caries did not significantly differ across adhesive modes at both 6-month and &gt;12-month evaluations (p&gt;0.05). This systematic review and meta-analysis suggested that UAs demonstrate comparable clinical performance to TE and SE adhesive systems in direct resin composite restorations, particularly in terms of restoration retention rates and the incidence of secondary caries. UAs applied in SEE mode exhibited superior clinical outcomes compared to other adhesive systems. These findings indicate that UAs can be considered a viable alternative to traditional adhesive systems in clinical practice, offering flexibility in application while maintaining comparable long-term outcomes.

Marginal Degradation of Universal Adhesive Restorations in NCCLs: A Systematic Review and Meta-analysis

Purpose This systematic review aimed to answer the PICO question: do adhesive protocols used for non-carious cervical lesions (NCCLs) using a universal adhesive system influence marginal degradation, marginal staining, and retention of these restorations? The self-etching adhesive strategy and selective enamel etching were compared with the etch-and-rinse strategy as a control. Materials and Methods The study searched various databases, including PubMed, Web of Science, Cochrane Central Register of Controlled Trials, Scopus, Embase, and grey literature, to find randomized clinical trials (RCTs) comparing self-etching (SE) or selective enamel etching (SEE) to the etch and rinse (ER) strategy. The risk of methodological bias was assessed using the Cochrane RoB 2 tool. Data were dichotomized and analyzed using RevMan v 5.3, adopting the Mantel-Haenszel method. The quality of evidence was assessed using Grading of Recommendations Assessment, Development and Evaluation (GRADE). Results Twenty RCTs were included in the meta-analysis. Results showed that using universal adhesives with the SE strategy resulted in clinical signs of marginal degradation at 12 months, 24 months, and 36 months of follow-up, and marginal staining at 24 months. The adhesive strategy did not interfere with the retention of restorative material used for NCCLs over 36 months, as assessed based on both the United States Public Health Service (USPHS) and World Dental Federation (FDI) criteria. Conclusion With moderate certainty of evidence, after 24 months of follow-up, the SE strategy results in the detection of clinical signs of marginal degradation and staining. The adhesive strategy adopted did not influence the retention rate of the restorations over 36 months of follow-up.

Effect of ionizing radiation on the shear bond strength of two different adhesive systems in primary teeth. in-vitro study

BackgroundRadiotherapy is a treatment modality used for head and neck cancer patients. It has a negative influence on bonding strength of adhesives. Little information is available about the effect of radiotherapy on bonding strength of adhesives in primary teeth. Therefore, this in vitro study aimed to detect the best adhesive system and ideal time to apply restorations in primary irradiated teeth regarding adhesive shear bond strength.MethodsDentin samples from primary teeth were randomly assigned to four groups based on restoration application time and radiation exposure, (G1: control, G2: preradiation, G3: 24 h postradiation, and G4: 6 months postradiation) with 20 samples per group. These groups were further divided into 2 subgroups according to the adhesive system used, with 10 samples per subgroup. (1) 3M™ Single Bond Universal Adhesive (SB), (2) 3M AdperSingle Bond 2 (AS). Samples were exposed to gamma radiation from a cobalt-60 machine. One shot of 60 Gy of radiation was delivered. Then samples were subjected to a shear bond strength test. The load was applied until failure and the maximum load was recorded. Numerical data are presented as mean and standard deviation values, then distributed according to Shapiro–Wilk test or Levene's test and analyzed via two-way ANOVA. The significance level was set at p < 0.05 for all tests. Statistical analysis was performed with R statistical analysis software version 4.4.1 for Windows (Team RC, R: A language and environment for statistical computing. R foundation for statistical computing, 2023).ResultsCompared with the AS subgroup, the SB subgroup presented significantly greater values (p < 0.001). For SB, there was no significant difference among the G1 and G4 groups (p > 0.001). However, there was a significant difference between G1, G2, and G3 (p < 0.001, P = 0.025, P = 0.265 ns respectively), and G3 presented the lowest values. For AS, there was no significant difference between groups G1 and G4 (p = < 0.001). Compared with the other groups, G3 presented a significant difference (p = 0.265 ns) and the lowest results.ConclusionRestorations performed 24 h after radiation had lower bond strength than those performed six months after radiation. Regardless of the adhesive system used, SB performed better than AS in terms of the shear bond strength.

Evaluation of Shear Bond Strength of Universal Adhesives to Dentin: in Vitro Study

Aim: Universal adhesives are widely used in restorative dentistry. The aim of this study was to evaluate the shear bond strength (SBS) of universal adhesives to dentin in different application modes. Materials and Methods: The study utilized seven universal adhesives and one total-etch adhesive. The sixty-four extracted intact human molars used in the study were embedded in acrylic blocks to the enamel-cement junction. The occlusal surface was removed to expose the dentin surface. After applying self-etch and total-etch adhesives to the dentin, flowable composite (Clearfil Majesty Flow, Kuraray) was placed in a transparent mold (2.38 mm diameter and 2 mm height) and polymerized. After thermal aging (1000 cycles), a SBS test has been carried out on a universal testing machine. The fracture types formed on the surface of the teeth were examined under a microscope. Data were analyzed by two-way analysis of variance (ANOVA) test (p&lt;0.05). Results: SBS values of universal adhesives on dentin showed statistically significant differences according to adhesive and application mode (p&lt;0.05). Total-etch application produced statistically higher SBS than self-etch application (p&lt;0.05). The two-step universal adhesive (G2 Bond Universal) had the highest SBS in both the self-etch and total-etch application modes (p&lt;0.05). When the bond surfaces of the universal adhesives were examined, fractures occurred most frequently in the adhesive type. Conclusion: The use of universal adhesives in the total-etch mode results in greater bond strength to dentin tissue. Universal adhesive type influences bond strength.

Influence of curing mode and aging on the bonding performance of universal adhesives in coronal and root dentin

BackgroundThis study aims to evaluate the microtensile bond strength (µTBS) of different resin composite restorations bonded to mid-coronal dentin and proximal root dentin using light-cured, chemical-cured, and dual-cured adhesives immediately and after aging. Nanoleakage and degree of cure were also assessed.MethodsEighty-four molars were divided into mid-coronal dentin and proximal root dentin. Each group was further subdivided into three subgroups based on the restorative systems used, which involved the utilization of light-cured, chemical-cured, and dual-cured adhesives. Half of the specimens underwent µTBS testing after 24 h, while the other half after aging. Representative specimens were analyzed for nanoleakage. The degree of cure of the tested adhesive systems was also assessed.ResultsAging showed a significant negative effect on µTBS results and led to increased nanoleakage (p < 0.001). Furthermore, in all subgroups, the µTBS values of proximal root dentin were lower compared to mid-coronal dentin, except in the aged subgroup for the system utilizing the dual-cured adhesive. The restorative systems with chemical and dual-cured adhesives demonstrated comparable bonding properties. However, the system with the light-cured adhesive exhibited the worst bonding properties after aging when bonded to proximal root dentin and cured at a large distance (p < 0.05).ConclusionsAll tested restorative systems were negatively affected by aging, and the regional dentin had variable effects on the bonding properties. Clinicians should exercise caution when using the tested light-cured adhesive in areas where the curing distance exceeds 3 mm.

Bonding strength of universal adhesives to laser-etched deep/superficial dentin

Bonding strength of universal adhesives to laser-etched deep/superficial dentin

Impact of functional monomers, bioactive particles, and HEMA, on the adhesive performance of self-etch adhesive systems applied to simulated altered dentin

ObjectivesThis study aimed to evaluate how self-etching/universal dental adhesive systems (DASs) with differing compositions interact with sound (S), post-radiotherapy (irradiated; I), and artificially eroded (E) dentin in terms of bonding properties. Methods: The DASs tested were Adper Scotchbond Multipurpose (MP; control), Clearfil SE Bond (SE), FL Bond II (FL), Adper Single Bond Universal (SU) and BeautiBond Xtreme (BX). They were analyzed for initial and 6-month microtensile bond strength (µTBS, n = 12), mode of failure (40 x), scanning electron microscopy (SEM), surface wettability (W, n = 10), and degree of conversion (DC, n = 3) via Fourier-transform infrared spectroscopy (FTIR). Normal and homogeneous distribution of the data allowed their analyses through ANOVA and Tukey tests (p < 0.05). Results: All DASs except BX exhibited higher µTBS for S decreasing for I and E. BX demonstrated the greatest stability among the altered substrates. FL showed the most hydrophobic properties, likely due to its bioactive components. Universal DASs achieved higher DC, regardless of composition. Conclusions: HEMA-free formulation combined with carboxylic and phosphoric acids in BX, achieved the most stable performance for altered substrates. Clinical SignificanceSince radiotherapy and erosion affect dentin, their characteristics compromise adhesive performance and impair the achievement of durable and satisfactory restorations. The use of universal adhesives less dependent on calcium seems less susceptible to hydrolytic degradation and may be a promising option for maintaining adhesive stability over time.

Novel GSK-3 inhibitor based universal dentin bonding system: A comprehensive analysis of dentinal repair and improved bond strength

The aim of the study was to describe the formulation of a novel universal adhesive system, based on a GSK-3 (glycogen synthetase kinase-3) inhibitor (Tideglusib®), and to evaluate its bond strength and dentinal repair capability. Tideglusib® was added to Ultradent Peak Universal Dentin Bonding Agent to make experimental adhesives (0.5 %, 1 %, 2 % final concentration). They were applied to teeth which were sectioned, stored for 24 h, or 2 years then bond strengths measured. Baseline stiffness of bonded dentin beams was tested using the three-point bending test. Animal experiments were performed to provide specimens for microcomputed tomography imaging after adhesive application. Collagen matrix was evaluated using transmission electron microscopy. The cytotoxicity of the modified adhesives was determined using fibroblastic cells. Molecular modelling evaluated binding of the Tideglusib® molecule to active sites on collagen and the adhesive components. TGFβ-1/and BMP-2 in human dentin matrices were measured and interfaces were scanned using SkyScan 2211. Adhesives’ stability tests were done. ResultsRMSD (root mean square deviation) analysis indicated simulation has equilibrated with changes for globular proteins (p < 0.05). Specimens from 0.5 %, and 1 % Tideglusib® groups displayed adhesive penetration with Micro-CT imaging and a significant increase in dentin density was seen. Specimens from the same groups showed cells with large masses of cytoplasm with focal adhesion points. Bond strength decreased significantly (p < 0.05) with increased storage time. Gradual release (p < 0.05) of both TGFβ-1 and BMP-2 from hTDMs with 0.5 % and 1 % Tideglusib® groups occurred and higher elastic moduli (p < 0.05). Collagen-based amide and proline Raman bands were seen in the Tideglusib® groups. ConclusionIncorporation of Tideglusib® in experimental Universal Adhesive System at 1 % improved adhesive bond strength and promoted dentinal repair. Application of Tideglusib® based adhesive conserve mechanical properties of the tooth structure and promote regenerative capability so can be expected to extend the service life of adhesive restorations in clinical situations.

The Effect of Micromechanical Surface Preparation and Adhesive Surface Modification Strategies on Resin-Matrix Ceramic Repair Bond Strength Using Universal Adhesive Containing Silane Agent

Abstract Objectives This research assesses the effect of the different micromechanical surface preparations and chemically adhesive surface modification strategies applied to resin-matrix ceramics (Shofu Block HC) repaired using resin composites. Materials and Methods Eighty resin-matrix ceramics were conducted and designed into eight groups of 10 specimens and surface treated with (1) micromechanical preparation with sandblast (SB) or hydrofluoric acid (HF), and (2) chemically adhesive techniques with HC primer (HC) and/or silane (Si) and/or conventional adhesive (AD) or universal adhesive (UA) designing are as follows: group 1, SB + HC; group 2, SB + HC + AD; group 3, SB + HC + Si + AD; group 4, SB + HC + UA; group 5, HF + HC; group 6, HF + HC + AD; group 7, HF + HC + Si + AD; and group 8, HF + HC + UA. An ultradent model was put on the specimen center, then filled resin composite. Mechanical testing instrument was used to determine the samples' microshear bond strength (MSBS). To inspect failure modes, a stereomicroscope was used for observing the debonded surfaces. Statistical Analysis To assess the data, a one-way analysis of variance was employed, and the significant level (p &lt; 0.05) was established with Tukey's test. Results Group 3 (29.29 ± 2.58 MPa) and group 4 (28.34 ± 1.26 MPa) demonstrated the two maximum MSBS values. The minimum MSBS (10.02 ± 3.31 MPa) was discovered by group 5. Nevertheless, group 2's MSBS values (22.78 ± 2.44 MPa) differed significantly from the values for groups 3 and 4. All the fractured samples in groups 1, 5, 6, 7, and 8 had an adhesive failure pattern. Furthermore, group 3 presented the greatest mixed failures (40%). Conclusion The SB is the most effective protocol for producing micromechanical retention. The application of HC primer and Si agent prior to the adhesive agent is the best chemical adhesive strategy for sandblasted resin-matrix ceramic surfaces. Additionally, the application of HC primer before the use of UA containing acid-resistant Si is the best alternative chemical adhesive strategy for improving the MSBS.

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 &amp; 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.

A Literature Review of Adhesive Systems in Dentistry: Key Components and Their Clinical Applications

The central aim of adhesive dentistry is to improve the compatibility between current adhesives and a range of substrates by employing diverse application techniques. Therefore, the overarching objective of this review is to offer a comprehensive analysis of dentin bonding systems, starting with an introduction to adhesion and a detailed overview of enamel and dentin structures, their histology, and the impact of dentin structure on resin–dentin bonding. It covers the mechanisms of resin–dentin bonding, including resin adhesive application, bonding mechanisms, and factors influencing efficacy. Further, this review explores the composition of resin adhesive systems, including acidic components, cross-linking monomers, solvents, and other critical elements. It also examines various adhesive strategies—etch-and-rinse, self-etch, and universal adhesives—highlighting their applications and advantages. The review extends to clinical applications of dental adhesion, including direct restorations, indirect restorations, and immediate dentin sealing (IDS), demonstrating the practical implications of adhesive systems in enhancing restoration longevity and performance. In conclusion, despite significant advancements, no gold-standard method for optimal adhesion exists. Each adhesive system has distinct strengths and limitations. The review emphasizes the importance of evaluating methods for achieving durable adhesion and staying current with technological advancements in adhesive systems. Summary: This review provides a thorough analysis of dentin bonding systems, delving into the structures and bonding mechanisms of both enamel and dentin. By exploring various adhesive systems and their components, it highlights the ongoing challenges in achieving optimal resin–dentin adhesion. The review also addresses the clinical applications of dental adhesion, including direct restorations, indirect restorations, and immediate dentin sealing (IDS), illustrating how different adhesive techniques impact clinical outcomes. It underscores the necessity for continuous innovation and assessment of adhesive systems to enhance long-term bonding effectiveness in clinical practice.

Comparison of Class II Bulk-Fill, Self-Adhesive Composites, Alkasite, and High-Viscosity Glass Ionomer Restorations in Terms of Marginal and Internal Adaptation.

(1) Background: Restoring decayed teeth in young patients can be challenging. This calls for a simplification of the protocols through new biomaterials. Therefore, the aim of this study was to compare the marginal adaptation delivered by restorative materials applied on class II cavities by using a simplified protocol, before and after fatigue test, followed by the assessment of the internal adaptation. (2) Methods: Forty-eight human teeth were divided into six groups (n = 8). Dentinal fluid simulation was performed before restoring the class II cavities: Gr 1-adhesive (Clearfil Universal Bond Quick) and nanohybrid flowable composite (Clearfil Majesty ES Super Low Flow), Gr 2-adhesive (Clearfil Universal Bond Quick) and nanohybrid composite (Clearfil Majesty ES standard), Gr 3-bulk fill self-adhesive composite (Surefil One), Gr 4-bioactive powder-liquid filling material (Cention Forte), Gr 5-universal adhesive (Adhese Universal) and nanohybrid composite resin (Tetric Powerfill); and control group (CT)-high-viscosity glass ionomer (Equia Forte). Marginal adaptation was observed with scanning electron microscopy (SEM) and compared before and after a fatigue test consisting of repeated thermal and mechanical cycles. The specimens were then cut mesio-distally, and internal adaptation was undertaken using SEM again. Repeated measures and one way ANOVA followed by a Fisher's LSD test and Fisher's LSD post hoc test were used in order to compare the statistically significant differences among groups. (3) Results: As for the marginal adaptation after loading, Cention Forte (58%) and Equia Forte HT (53%) were statistically equivalent and presented the highest results, followed by Clearfil Majesty ES Standard (32%) and Tetric Powerfill (27%), with Surefil One (8%) and Clearfil Majesty ES Flow Super Low (7%) showing the worst results. In terms of internal adaptation, Cention Forte (85%) and Clearfil Majesty ES Standard (74%) had the highest percentages of continuous margins. Tetric powerfill (56%) and Equia Forte HT (44%) showed statistically significantly lower results, followed by Clearfil Majesty ES Flow Super Low (33%) and eventually Surefil One (17%). (4) Conclusions: This in vitro study showed promising results for the marginal and internal adaptation of alkasite dual cured Cention Forte in the restoration of class II cavities. This material could be considered an interesting restorative alternative for the restoration of deciduous teeth.

Effect of adding sodium fluoride and nano-hydroxyapatite nanoparticles to the universal adhesive on bond strength and microleakage on caries-affected primary molars.

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.

Long-Term Bonding Efficacy of CAD/CAM Hybrid Restorative Materials and Universal Adhesives.

In-office and lab milled prostheses are the staple for indirect restorations. It is therefore critical to determine their long-term bonding durability. CAD/ CAM blocks of two classes of restorative materials: 1) a nano-ceramic reinforced polymer matrix (NCPM) and, 2) a polymer-infiltrated ceramic network (PICN) were bonded using four different universal adhesives (UA) and silane systems. A lithium disilicate glassceramic (LDS) was used as a reference. The blocks were bisected and bonded with different UA/resin-cement pairs. Bonded blocks were then cut into 1.0x1.0x12.0 mm bar specimens for microtensile bond testing. Half the bars were subjected to bond strength testing immediately and the other half after aging by 50,000 thermal cycles between 5°C and 55°C. ANOVA and post-hoc tests were used to compare mean bond strength among groups. NCPM presented consistently high bond strength regardless of bonding techniques, while the bond strength of PICN and LDS were lower when bonded with UA relative to traditional silanes. The more hydrophilic UA produced higher bond strengths. Glass-ceramics exhibited lower bond strength with UA than the conventional etch-rinse-silane techniques. However, UAs preserved bonding interface in the long-term. NCPM displayed superior bond strength relative to PICN and LDS regardless of the type of adhesives and bonding techniques.

Comparative Evaluation of Microtensile Dentin Bond Strength and Interfacial Micromorphology of Three Universal Adhesives.

To assess and compare the microtensile dentin bond strength (μTBS) and interfacial micromorphology of three universal adhesives. 96 human molars were assigned to three universal adhesives: Single Bond Universal (SBU), CLEARFIL Universal Bond Quick (UBQ), and RE-GEN Universal Adhesive (REGEN). Adhesives were applied in self-etch mode. SBU and REGEN were applied following the manufacturers' instructions. UBQ was divided into two subgroups: one following the manufacturer's instructions (UBQ Short) and the other with an extended application time (UBQ Extended). Teeth were restored with nanohybrid resin composite. Specimens were divided into immediate and delayed subgroups. The delayed subgroups were stored for 6 months and subjected to 5000 thermocycles. μTBS was tested, and failure mode was analyzed. Interfacial micromorphology was assessed using a scanning electron microscope. The data were statistically analyzed (p⟨ 0.05). The adhesive choice, aging, and their interaction significantly affected μTBS. SBU exhibited the highest immediate μTBS, comparable to UBQ (Extended) and REGEN, and significantly higher than UBQ (Short). In delayed testing, SBU outperformed the other adhesives. Aging negatively affected the μTBS of UBQ and REGEN, while SBU wasn't affected. The quick application concept of UBQ deteriorated its μTBS compared to the extended application time.

Bonding To Zirconia With A Recently Introduced Universal Adhesive. An In-vitro Study

Bonding To Zirconia With A Recently Introduced Universal Adhesive. An In-vitro Study

Shelf-life effect of silane-containing universal adhesive on bonding effectiveness to glass-ceramic

ObjectiveTo evaluate the shelf-life effect of a silane-containing universal adhesive (UA) on its shear bond strength (SBS) to lithium disilicate glass-ceramic (LiSi2). MethodsSBS to mirror-polished (‘MP’) and hydrofluoric acid-etched ground (‘HF’) lithium disilicate glass-ceramic (Initial LiSi, GC) with/without prior separate ceramic primer application (G-Multi Primer, GC: ‘G-MP’) was measured. Scotchbond Universal Plus (‘SBUp’) (3M Oral Care) was used 33 (‘fresh’) and 6 (‘expiring’) months before the expiration date. ‘MP’ specimen preparation involved (1) ‘G-MP’ priming (or not), (2) ‘SBUp’ application, (3) composite (Clearfil AP-X, Kuraray Noritake) placement, and (4) 20 s light-curing (SmartLite Pro, Dentsply Sirona). ‘HF’ specimen preparation involved (1) HF (Porcelain Etch, Ultradent) etching, (2) phosphoric acid (K-Etchant, Kuraray Noritake) post-etching, with (3) and (4) being the same as for ‘MP’. Upon light-curing, all specimens were stored in 37 °C water for either 1 week (‘immediate’) or 3 months (‘aged’) prior to SBS measurement. Statistics involved Linear Mixed-Effects modelling (α = 0.05). ResultsSBS was not significantly affected by SBUp's shelf life, except for a significantly higher SBS recorded for ‘fresh’ SBUp applied on HF-etched and separately silane-primed LiSi2. Aging did not significantly decrease SBS. In fact, a significant increase in SBS upon aging was recorded for HF-etched LiSi2 that was not separately silane-primed. The significantly highest bond strength was measured when LiSi2 was HF-etched followed by separate silane-priming. SignificanceDespite the UA investigated has silane in its formulation, the most effective and durable bonding to LiSi2 was achieved by HF-etching followed by separate silane-priming, irrespective of the UA's shelf life.

Do in vitro and in situ erosive challenges alter the bonding performance of universal adhesives?

ObjectiveTo evaluate microtensile bond strengths (μTBS), nanoleakage (NL), and degree of conversion (DC) of two universal adhesives, using etch-and-rinse (ER) or self-etch (SE) strategies on eroded dentin submitted to in vitro and in situ erosive challenges. MethodsDentin blocks were prepared from 120 human molars and categorized based on dentin condition (sound, in vitro eroded, and in situ eroded), adhesive system (Scotchbond Universal [SBU] and Zip bond Universal [ZIP]), and adhesive strategy (ER and SE). In the in situ erosive challenge, 20 volunteers wore acrylic resin palatal devices with dentin blocks, immersing them in cola soft drink for 90 s, six times daily for 15 days. The same erosive protocol was used in vitro, followed by rinsing and remineralization. Sound dentin blocks served as controls. Afterward, all dentin blocks were restored with composite resin and sectioned into resin-dentin bonded sticks for μTBS, NL, and DC assessments. Data were analyzed using three-way ANOVA and Tukey's test (α = 0.05). ResultsSound dentin exhibited the highest μTBS and DC values and the lowest NL values, while in situ eroded dentin showed the lowest μTBS and DC values and the highest NL values (p = 0.000001). While some differences in the μTBS values were observed between universal adhesives when evaluated on sound dentin (p = 0.0001), no significant differences between adhesives were observed when tested on in vitro and in situ eroded dentin. Regarding NL and DC, no significant differences were found between SBU and ZIP, as well as among adhesive strategies (p > 0.05). ConclusionErosion in dentin, especially under in situ conditions, presents significant challenges to the adhesion of restorative materials. The choice of an effective adhesive system is crucial, as dentin eroded in situ showed lower adhesion strength and greater nanoleakage. These results highlight the need for specific clinical strategies to improve the durability and effectiveness of restorations.