Performance of self-etching adhesives on caries-affected primary dentin treated with glutaraldehyde or silver diamine fluoride.

OBJECTIVES: to evaluate the quality and stability of adhesive interfaces established by self-etching adhesives on caries-affected primary dentin (CAD) treated with glutaraldehyde (GA) or silver diamine fluoride (SDF). METHODS: 42 primary molars were exposed to a microbiological caries-inducing protocol and divided into 6 groups according to the adhesive system (Clearfil SE - CL or FL Bond II - FL) and pretreatment (water, GA or SDF) applied on CAD. One tooth from each group was analyzed for surface modification using infrared spectroscopy. Crowns were restored with resin composite (n = 36) and cut into beams and slices. The beams were subjected to microtensile testing, Raman spectroscopy and SEM after 24 h and 6 months of storage. The slices were analyzed using Micro-Raman spectroscopy to determine the diffusion zone thickness (DZ) in each period. Data were analyzed by ANOVA and Tukey or Kruskal-Wallis and Dunn tests (α = 0.05%). RESULTS: SDF reduced the immediate bond strength for both adhesives. The control groups showed a decrease in BS after 6 months in artificial saliva. GA increased immediate DZ for FL, while SDF had the opposite effect on CL. GA decreased the DZ for FL at 6 months. There was a predominance of adhesive failures with areas of cohesive dentin fractures within control groups. SIGNIFICANCE: Modifications caused by dentin surface treatments may directly affect the performance of adhesive systems and the quality and stability of adhesive restorations.

Systematic review and network meta-analysis of restorative therapy and adhesive strategies in root caries lesions.

AIM: This systematic review and network meta-analysis (NMA) aimed to establish a clinically relevant hierarchy of the different adhesive and/or restorative approaches to restore cavitated root caries lesions through the synthesis of available evidence. MATERIALS AND METHODS: A systematic search was conducted in Medline/Web of Science/Embase/ Cochrane Library/Scopus/grey literature. RCTs investigating ≥2 restorative strategies (restorative /adhesive materials) for root caries lesions in adult patients were included. Risk of bias within studies was assessed (Cochrane_RoB-2) and the primary outcome was survival rate of restorations at different follow-up times (6-/12-/24-months). Network meta-analyses were conducted using a random effects model stratified by follow-up times. I2-statistics assessed the ratio of true to total variance in the observed effects. All available combinations of adhesives (1-SE: one-step self-etch; 2-3ER: two-/three-step etch-and-rinse) and restorative materials (conventional composite (CC) as well as conventional and resin-modified glass ionomer cements (GIC, RMGIC)) were included. Risk of bias across studies and confidence in NMA (CINeMA) were assessed. RESULTS: 547 studies were identified and nine were eligible for the NMA. In total, 1263 root caries lesions have been restored in 473 patients in the included clinical trials. Patients involved were either healthy (n = 6 trials), living in nursing homes (n = 1 trial) or received head-and-neck radiotherapy (n = 2 trials). There was statistically weak evidence to favour either of material/material combination regarding the survival rate. A tendency for higher survival rate (24-months) was observed for 2-3ER/CC (OR24mths 2.65; 95%CI=1.45/4.84) as well as RMGIC (OR24mths 2.05; 95%CI=1.17/3.61) compared to GIC. These findings were though not statistically significant and confidence of the NMA was low. CONCLUSION: An evidence-based choice of restorative strategy for managing cavitated root caries lesions is currently impossible. There is a clear need for more standardised, well-designed RCTs evaluating the retention rate of root caries restoration approaches.

Enhanced Bonding to Caries-Affected Dentin Using an Isocyanate-Based Primer.

Dental caries is the most common oral disease and the most common cause of resin restorations. In minimally invasive dentistry, the principle behind cavity preparation is to remove external caries-infected dentin (CID) and preserve internal caries-affected dentin (CAD) and sound dentin (SD). The cavity floor is mainly composed of CAD, but the poor bonding performance of CAD has become a widespread concern. This study evaluated the performance of a new collagen-reactive monomer (ITCM) used as a primer to improve the bonding performance of CAD. The experimental specimens were grouped as follows: SD, CAD, and ITCM-pretreated CAD (CAD-ITCM). Dentin slices were obtained for attenuated total reflectance-Fourier transform infrared (ATR-FTIR) analysis. The bonded samples were subjected to microtensile bond strength analysis after 24 h of water storage or aging by thermocycling, and the bonding interface quality was evaluated by nanoleakage assessment, interfacial nanoindentation testing, and in situ zymography. Cytotoxicity experiments with ITCM were performed. ATR-FTIR showed that the isocyanate groups in ITCM can covalently bind and form hydrogen bonds with the collagen in CAD to mediate chemical bonding. ITCM pretreatment significantly improved the bond strength of CAD (P < 0.05), reduced interfacial nanoleakage, improved the sealing of the bonding interface, enhanced the homogeneity of the hybrid layer, and inhibited matrix metalloproteinase activity. In addition, ITCM presented acceptable biocompatibility for dental restorative application. Taken together, this study reported the application of ITCM to induce collagen-based chemical bonding in the CAD bonding system, which fills the gap in strategies to improve the bonding performance of CAD immediately and after aging and has important clinical application prospects.

Influence of universal adhesives and silane coupling primer on bonding performance to CAD-CAM resin-based composites: A laboratory investigation.

OBJECTIVE: Obtaining strong resin bonds to computer-aided design and computer-aided manufacturing (CAD-CAM) resin-based composites with dispersed fillers (CCRBCs) poses a challenge. Therefore, this study aimed to assess the effect of three universal adhesives and a two-component silane coupling agent on the shear bond strength to three (CCRBCs). MATERIALS AND METHODS: Eight hundred and sixty-four specimens of Brilliant Crios, Lava Ultimate, and Tetric CAD were polished or grit blasted, bonded with Adhese Universal DC, One Coat 7 Universal (OC7), and Scotchbond Universal Plus Adhesive (SBU) with or without a silane primer. Shear bond strength was measured after 24 h and 10,000 thermocycles. Linear regressions were performed (α = 0.05). RESULTS: After thermocycling, bond strengths were similar for the universal adhesives on polished Brilliant Crios and Lava Ultimate (p ≥ 0.408). Grit blasted Tetric CAD showed no significant differences (p ≥ 0.096). The silane primer had minimal impact on grit blasted Tetric CAD (p ≥ 0.384). The silane primer increased the bond strength of OC7 to Brilliant Crios (p = 0.001) but decreased the adhesion of SBU to Brilliant Crios and Lava Ultimate (p ≤ 0.018). CONCLUSIONS: Bond strength of universal adhesives varied with CCRBC type. The two-component silane coupling agent showed mixed effects on adhesive performance. CLINICAL SIGNIFICANCE: Selecting universal adhesives from the same CCRBC product line does not always guarantee superior bond strength. The efficacy of silane coupling agents differs based on the bonding substrate.

Survival assessment of fractured porcelain-fused-to-metal crowns surface roughened by sandblasted and repaired by composite resin after in vitro thermal fatigue.

Background/purpose: Intraoral repair usually takes the convenience of the patient's daily life as the starting point, taking into account the bonding strength, operational feasibility, and safety. This study aimed to evaluate the survival of composite resin by simulating cavity fracture repair in porcelain-fused-to-metal (PFM) crowns and referring to the G.V. Black classification of caries as ceramic- and metal-site exposure. Materials and methods: Mechanical sandblast experimental and a nonsandblast control groups comprised 120 samples, and interfacial locking was enhanced through acid etching, bonding, and light-curing composite resin restoration. Classes of VI buccal (B), III mesial (M), and IV mesiobuccal (MB) types, were investigated. Load tests were performed on two sets, with one set at room temperature for 24 h and the other via thermal cycling at 5 °C/50 °C 720 times. Loading was gradually applied to the samples until a maximum of 450 N was reached. Results: Results showed that 24 h survival rates of B-, M - , and MB-repaired PFM crowns were 88%, 84%, and 88%, respectively. The repaired PFM survival rates for B, M, and MB were 52%, 44%, and 28%, respectively, after thermal cycling and loading tests. Multiple logistic regression and chi-square test (α = 0.05) showed that the regression results of factors affecting survival assessment were only significant between groups after thermal fatigue (P < 0.05). Survival rate of repairing metal-site in the MB model was significantly higher than that of ceramic-sites repairing in non-blasted samples. For the MB cavity model, sandblasting can significantly improve the survival rate of the repair of ceramic parts in the MB model (P < 0.05). Conclusion: Our results suggest that sandblasting can be further considered, especially for MB cavity fractures when ceramic-site restorations are required.

Concentration effect of DMSO-dry bonding on the stability of etch-and-rinse bonds.

OBJECTIVES: To examine whether lower dimethyl sulfoxide (DMSO) concentrations would affect long-term bond stability of simplified or multistep water-based adhesives to dry-etched dentin. METHODS: H3PO4-etched mid-coronal dentin surfaces from human molars were randomly blot- or air-dried for 30 s and pretreated or not with 5 or 50 % (v/v) ethanolic DMSO solutions. Untreated samples served as control. Samples were bonded with a two-step or a three-step etch-and-rinse adhesive. Restored crown segments (n = 5/group) were stored in distilled water for 24 h and sectioned for microtensile bond strength testing. Resin-dentin beams (0.8 mm2) were tested under tension until fracture (0.5 mm/min) after 24 h and one year of storage in artificial saliva at 37 °C. Nanoleakage evaluation and hybrid layer characterization were performed by SEM. Bond strength data was examined by three-way ANOVA followed by the Tukey test (α = 0.05). RESULTS: Dry bonding produced significantly lower bond strengths than conventional wet bonding for both water-based adhesive systems (p < 0.05). DMSO-dry bonding restored bond strengths and reduced nanoleakage levels, regardless of adhesive type or DMSO concentration (p < 0.05). Bond strengths of DMSO-dry bonded samples were not significantly affected by long-term ageing regardless of adhesive type or DMSO concentration (p < 0.05). SIGNIFICANCE: Although bonding methacrylate-based resins to etched dentin is normally performed under wet conditions, hybridization of air-dried collagen can outperform conventional wet bonding by employing water-free DMSO solutions with concentrations as low as 5 %. Reduced moisture-related technique sensitivity, higher bonding performance and improved hybrid layer stability may contribute to extend the service life of resin-dentin bonding.

Comparative Study on Interface Fracture of 4th Generation 3-Steps Adhesive and 7th Generation Universal Adhesive.

The purpose of this paper is to compare the fracture behavior of interfaces obtained using fourth-generation and universal dental adhesives. The study relies on optic and SEM to evaluate the dentin-adhesive-restoration material interface of the samples and also on FEA simulation of fracture behavior. Specimen fabrication relied on 20 extracted teeth, in which class I cavities were created according to a protocol established based on the rules of minimally invasive therapy. For the direct adhesive technique, the adhesives used were: three-step All Bond, three-batch A and one-step Clearfil Universal Bond Quick-batch B. The restoration was performed with the same composite for both adhesives: Gradia direct posterior. The simulation used a 3D reconstructed molar on which geometric operations were performed to obtain an assembly that replicated a physical specimen. Material properties were applied to each component based on the information found in the literature. A simplified model for crack propagation was constructed, and using the fracture mechanics tool in Ansys 2019, the stress intensity factors that act at the crack tip of the adhesive interface were obtained. Mechanical simulation and microscopic investigation showed us how the interface of the dentine-adhesive-filling material performed in cases of both dental adhesives and for a certain loading condition. Important differences were identified among the adhesives, the fourth generation being superior to the fourth generation especially due to the separate steps in which the tooth surface was prepared for adhesion.

Development of a Boron Nitride-Filled Dental Adhesive System.

There is a dearth of adhesive systems capable of forming stable bonds between restorative materials and tooth surfaces. To address the concern, this study determined the effects of using methacrylate-functionalized boron nitride nanosheets (BNNSs) in a polymeric dental adhesive system. The bisphenol A glycidyl dimethacrylate (BisGMA):2 hydroxyethyl methacrylate (HEMA) (60:40) adhesive monomer blend with a photoinitiator was filled with 0 wt% (control), 0.1 wt%, and 1 wt% BNNSs and light cured. Fourier transform infrared spectroscopy was performed to determine the conversion degree of monomer double bonds (DoC). Water absorption and solubility were measured. Flexural strength and Youngs's modulus were evaluated to determine the mechanical properties of the composite adhesive system. Finally, dentin bond strength degradation and fracture mode were quantified with a microtensile bond test to confirm the bonding ability of the developed adhesive system. Results showed that the incorporation of BNNSs increased DoC (9.8% and 5.4% for 0.1 and 1 wt%, respectively), but it did not affect water sorption (101.9-119.72 (µg/mm3)), solubility (2.62-5.54 (µg/mm3)), Young's modulus (529.1-1716.1 MPa), or microtensile bond strength (46.66-54.72 MPa). Further studies are needed with varying BNNS loading percentages from 0.1 wt% to 1 wt% in order to more comprehensively determine the effect of BNNSs on dental adhesives.

Pushout Bond Strength in Coronal Dentin: A Standardization Approach in Comparison to Shear Bond Strength.

To find an alternative that is closer to clinical reality in terms of cavity geometry and configuration factor, this study investigated the pushout test on in vitro adhesive testing to coronal dentin when compared to the established shear test, both in a standardized approach. For a feasible comparison between both tests, the pushout specimen was adjusted in thickness (1.03 ± 0.05 mm) and cavity diameter (1.42 ± 0.03 mm) to receive a bonding area (4.63 ± 0.26 mm2) that matches that of the shear test (4.57 ± 0.13 mm2). Though, the configuration factor between both tests differs largely (pushout 1.5 ± 0.08; shear bond 0.20 ± 0.01). The bond strength of five different adhesives (n = 20) was investigated for both tests. The pushout test registered a high number of invalid measurements (30%) due to concomitant dentin fracture during testing. In contrast to the shear test, the pushout test failed to discriminate between different adhesives (p = 0.367). Both tests differed largely from each other when comparing adhesive groups. When solely looking at the valid specimens, Weibull modulus reached higher values in the pushout approach. Conclusively, the pushout test in this specific setup does not distinguish as precisely as the shear bond test between different adhesives and needs adaption to be routinely applied in adhesive dentistry.

Analyses of Experimental Dental Adhesives Based on Zirconia/Silver Phosphate Nanoparticles.

This study aimed to evaluate the incorporation of zirconia/silver phosphate nanoparticles to develop experimental dental adhesives and to measure their physical and mechanical properties. The nanoparticles were synthesized by the sonication method, and the phase purity, morphological pattern, and antibacterial properties with Staphylococcus aureus and Pseudomonas aeruginosa were assessed. The silanized nanoparticles were incorporated (0, 0.15, 0.25, and 0.5 wt.%) into the photoactivated dimethacrylate resins. The degree of conversion (DC) was assessed, followed by the micro-hardness and flexural strength/modulus test. Long-term color stability was investigated. The bond strength with the dentin surface was conducted on days 1 and 30. The transmission electron microscopy and X-ray diffractogram confirmed the nano-structure and phase purity of the particles. The nanoparticles showed antibacterial activities against both strains and inhibited biofilm formation. The DC range of the experimental groups was 55-66%. The micro-hardness and flexural strength increased with the concentration of nanoparticles in the resin. The 0.5 wt.% group showed significantly high micro-hardness values, whereas a non-significant difference was observed between the experimental groups for flexural strength. The bond strength was higher on day 1 than on day 30, and a significant difference was observed between the two periods. At day 30, the 0.5 wt.% showed significantly higher values compared to other groups. Long-term color stability was observed for all the samples. The experimental adhesives showed promising results and potential to be used for clinical applications. However, further investigations such as antibacterial, penetration depth, and cytocompatibility are required.

Are polywave light-emitting diodes more effective than monowave ones in the photoactivation of resin-based materials containing alternative photoinitiators? A systematic review.

OBJECTIVE: This systematic review aimed to analyze if using polywave light-emitting diodes (LED) to photoactivate resin-based materials (resin composites, adhesive systems, and resin cements) containing alternative photoinitiators provide better physicochemical properties than monowave ones. MATERIAL AND METHODS: Inclusion criteria were in vitro studies that evaluated the degree of conversion, microhardness and flexural strength in resin-based materials containing alternative photoinitiators and light-activated with mono and polywave LEDs. Exclusion criteria were studies that evaluated the physicochemical properties of composites through any material interposed between the LED and the resin composite and studies that exclusively compared different modes and/or light activation times. Selection of studies, data extraction, and risk-of-bias analysis was performed. Data from selected studies were qualitatively analyzed. A systematic search was performed in June 2021 using PubMed/Medline, Embase, Scopus, and ISI Web of Science databases and grey literature without language restriction. RESULTS: A total of 18 studies were included in the qualitative analysis. Nine studies used diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide (TPO) as an alternative photoinitiator for resin composite. Polywave LED improved the degree of conversion of resin composite compared to monowave in 9 of the included studies. Polywave LED improved the microhardness of resin composite compared to monowave in 7 of the included studies. Polywave LED improved the degree of conversion for 11 studies and microhardness of resin composite compared to monowave for 7 included studies. No differences in the flexural strength medium between poly and monowave LEDs were observed. The evidence was graded as low quality due to the high risk of bias for 11 studies. CONCLUSION: The existing studies, with their limitations, revealed that the polywave light-emitting diode maximizes activation, resulting in a higher degree of double-bond conversion and microhardness of resin composites containing alternative photoinitiators. However, the flexural strength of these materials is not influenced by the type of light activation device.

Influence of geometric dimensions on early failures of adhesively retained composite resin core build-ups.

OBJECTIVE: To determine the influence of the geometric dimensions of core build-ups on early core build-up failure, that is, loss before definitive prosthesis cementation. MATERIALS AND METHODS: Adhesive core build-ups of exclusively vital teeth in 114 participants were evaluated (n materials: 40 Rebilda DC, 38 Multicore Flow, 36 Clearfil DC Core; n teeth: 8 incisors, 54 premolars, 52 molars). Impressions of the abutment teeth were made (1) after removal of insufficient restorations/caries and (2) after core build-up and preparation for a fixed prosthesis. Digitized model surfaces of both situations were aligned (Geomagic Design X) and core build-up volume (VCBU ), remaining hard tissue volume (VAbut ), and size of the adhesive surface (Aadh ) were assessed. The derived measure dCBU  = VCBU /Aadh can be interpreted as mean arithmetic core build-up thickness. Associations between participant or core build-up design characteristics and the occurrence of early failures were statistically evaluated (SPSS v27, α = 0.05). RESULTS: A total of six (5.3%) core build-up failures were registered. Higher participant age, greater core build-up volume VCBU and greater arithmetic uniform thickness dCBU were associated with a greater incidence of failure in bivariate and univariate, however, not in multivariate statistics. CONCLUSIONS: Core build-up volume and thickness were associated with early success or failure. CLINICAL SIGNIFICANCE: In the case of voluminous/thick core build-ups in relation to the adhesive surface, additional measures, such as the preparation of retentive elements to increase the bonding area, might be considered to reduce the risk of early core build-up failure.

Survival rates of mandibular fixed retainers: comparison of a tube-type retainer and conventional multistrand retainers : A prospective randomized clinical trial.

OBJECTIVE: The purposes of this study were to evaluate the survival rate of a tube-type mandibular fixed retainer and compare it to conventional multistrand retainers. MATERIALS AND METHODS: In all, 66 patients who had completed their orthodontic treatment were enrolled in this study. They were allocated randomly to a tube-type retainer group or a 0.020 multistrand fixed retainer group. In case of the tube-type retainer, a thermoactive 0.012 NiTi was placed into 6 mini-tubes passively bonded to the anterior teeth. The patients were recalled at 1, 3, 6, 12, and 24 months after retainer placement. During the 2­year follow-up period, any first-time failure of retainers was recorded. Kaplan-Meier survival analysis and log-rank tests were used to compare the failure rates between the two types of retainers. RESULTS: Of the 34 patients, 14 (41.2%) showed failure in the multistrand retainer group, whereas only 2 of 32 (6.3%) reported failure in the tube-type retainer group. There was a statistically significant difference in failure between the multistrand retainer and the tube-type retainer (log-rank test, P = 0.001). The hazard ratio was 11.937 (95% confidence interval 2.708-52.620; P = 0.005). CONCLUSION: The tube-type retainer can be used with fewer concerns about recurrent retainer detachments during orthodontic retention.

Comparison of Different Universal Adhesive Systems on Dentin Bond Strength.

Over the past few decades, adhesive dentistry has advanced significantly. In light of minimal-invasive dentistry, this novel technique advocates a more conservative cavity design that relies on the efficiency of present enamel-dentine adhesives. The study aimed to address the scientific deficit in understanding the long-term bonding performance of universal adhesives and to provide a new clinical solution with desirable bond strength to dentin. The dentin bond strength of three bonding agents, G2-Bond Universal (GC), Clearfil SE Bond (Kuraray), and Scotchbond Universal Plus (3M ESPE), was evaluated following various storage and etching modes. The UltraTester (Ultradent) bond strength testing machine was used to assess shear bond strength. The results showed that thermal cycling and the choice of adhesive system significantly affected the shear bond strength (p = 0.018 and p = 0.001, respectively). Among the three adhesives, Scotchbond Universal Plus had the lowest bond strength value (mean value = 24.78 MPa), while G2-Bond Universal was found to have desirable shear bond strength to dentin compared to the other adhesives, even after one year in the oral environment (mean value = 35.15 MPa). These findings imply that the HEMA-free universal adhesive G2-Bond Universal is the most effective universal adhesive for clinical practices, particularly when applied in the self-etch mode.

Effectiveness of immediate dentine sealing and resin coating in reducing dental sensitivity in a child with idiopathic neuropathy and anterior dental attrition: Case report.

BACKGROUND: Idiopathic neuropathy is a peripheral nervous system disorder of unknown etiology. Patients with this disorder often suffer from bruxism problems. Bruxism is defined as an oral parafunction characterized by occlusal contacts resulting from non-physiological, repetitive, and involuntary masticatory motor activities. These events can trigger accentuated wear of the tooth structure leading to sensitivity. Tooth sensitivity is the pain arising from the exposed dentin in response to chemical, thermal, tactile, or osmotic stimuli that cannot be explained as the result of any other dental defect or disease. Sensitivity treatment using adhesive systems has a long-term or permanent effect. Therefore, this article is aimed at describing the management of dental sensitivity, through dentin sealing and resin coating techniques, during the dental restoration process of a child with idiopathic neuropathy and dental attrition in the anterior sector. All of this, with the consideration of using the minimal intervention philosophy. CASE PRESENTATION: A 6-year-old male patient diagnosed with idiopathic neuropathy and suffering from multiple dental attritions with dental sensitivity in the upper anterior teeth. With the clinical-radiographic evaluation, the family history, and the interconsultations with the neuropaediatrics service, the definitive diagnosis of dental sensitivity due to stage-3 moderate attrition was obtained, for which rehabilitation of the upper anterior sector was planned through the use of immediate dentin sealing (IDS) and resin coating (RC). CONCLUSION: The use of IDS and RC techniques shows acceptable sensitivity, which is why these techniques are recommended in cases of moderate attrition in early mixed dentition. The immediate rehabilitation along with the stamping technique improved the aesthetic and functional aspects. Therefore, it is advisable to use them immediately after dentin sealing.

Can composite packaging and selective enamel etching affect the clinical behavior of bulk-fill composite resin in posterior restorations? 24-month results of a randomized clinical trial

Abstract Objectives This is a double-blind, split-mouth, randomized clinical study that aims to evaluate the influence of bulk-fill composite packaging presented in syringes (BSy) and capsules (BCa), and the effect of selective enamel etching (SEE) on the clinical performance of class I and II bulk-fill resin composite restorations after 24 months. Methodology A total of 295 class I or class II restorations were performed on 70 patients. One universal adhesive was applied in all restorations. SEE was used in 148 restorations and self-etching mode (SET) in 147 restorations. After the adhesive application, cavities were restored with Filtek Bulk-fill Posterior Restorative in syringes (BSy), Filtek One Bulk-fill in capsules (BCa), or Filtek Supreme Ultra in syringes with the incremental technique (In). All restorations were evaluated using the FDI criteria after one week and after six, 12, and 24 months. Kaplan-Meier survival analysis and Pearson's Chi-square test were used (α=0.05) for statistical analysis. Results After 24 months, 62 patients were evaluated and four restorations were lost due to fracture (one for SEEBSy, two for SEEIn, and one for SETIn). No significant differences in the fracture and retention rate were found between groups (p>0.05). SEE showed significantly fewer marginal adaptation defects than SET (p<0.05). BCa and BSy groups showed fewer marginal discrepancies compared to In (p<0.05). Restorations performed with BCa showed less color mismatch than BSy or In (p<0.05). Conclusion Although all restorations exhibited satisfactory clinical performance after 24 months of clinical service, the clinical behavior of class I and II restorations' improved when performed with a bulk-fill composite in capsules, mainly when associated with a universal adhesive applied with SEE.

Is the adhesive or mechanical behavior of glass ceramics influenced by the adhesive layer application after etching and silanization? A literature review

Aim: This review investigated the effect of applying an adhesive after surface treatment of glass-ceramics on the bonding, mechanical or clinical behavior. Methods: Studies comparing the adhesive, mechanical or clinical behavior of glass-ceramics, with or without adhesive application after surface treatment, were included. Searches were performed in PubMed, Scopus, and Web of Sciences databases (January 2022), resulting in 15 included studies. Results: Regarding the evaluated outcomes, 13 studies assessed bond strength, 2 studies assessed biaxial flexural strength and 1 study assessed fatigue failure load, while no study evaluating clinical outcomes was included. It was possible to observe that the adhesive application after ceramic surface treatment was unfavorable or did not influence the evaluated outcomes. Conclusion: Most of the evidence available in the literature shows that the adhesive application after surface treatment does not improve the adhesive and mechanical behavior of glass-ceramics

Resistência ao cisalhamento de bráquetes colados com diferentes fotopolimerizadores led de alta potência / Shear strength of brackets bonded with different high-power led light curing

Resumo OBJETIVO: Avaliar a resistência ao cisalhamento e o Índice de Remanescente Adesivo (IRA) de bráquetes metálicos colados com três diferentes fotopolimerizadores LED de alta potência, quando comparados ao LED convencional. MATERIAIS E MÉTODOS: 80 incisivos bovinos foram divididos aleatoriamente em 4 grupos (n=20), nos quais foram realizadas colagens dos bráquetes utilizando-se os seguintes LEDs de alta potência por 3s: Grupo 1 ­ LEDX ­ T 2400, Orthometric; Grupo 2 ­ Flashmax P4 PRO Ortho, Rock Moutain Orthodontics; Grupo 3 ­ VALO CORDLESS, Ultradent e Grupo 4 ­ LED convencional por 40s (controle) POLY-WIRELESS, Kavo. O teste de resistência ao cisalhamento foi realizado utilizando-se uma máquina de ensaio universal (AME-2kN, Oswaldo Filizola, São Paulo, Brasil) com velocidade de 0,5mm/min e célula de carga de 50N. A determinação da diferença estatística entre os grupos em relação ao cisalhamento foi realizada usando-se a análise de variância (ANOVA). Para avaliação do IRA, foi aplicado o teste Kruskal-Wallis. RESULTADOS: O grupo 2 apresentou resistência ao cisalhamento significativamente superior aos demais LEDs de alta potência e foi similar ao LED convencional. Em relação ao IRA, houve diferença estatisticamente significante entre os grupos e o único que não diferiu do grupo controle foi o 2, enquanto os demais LEDs de alta potência (Grupos 1 e 3) apresentaram mais falhas adesivas entre a resina e o esmalte. CONCLUSÃO: Houve diferença entre os três tipos de fotopolimerizadores LED de terceira geração, sendo que maior resistência ao cisalhamento e menos falhas adesivas foram observadas no LED que apresentou maior potência (AU)

Abstract OBJECTIVE: To evaluate shear strength and Adhesive Remnant Index (ARI) of metallic brackets bonded to three types of high-power LED light curing, when compared to conventional LED. MATERIALS AND METHODS: 80 bovine incisors were divided into 4 groups (n = 20), in which brackets were bonded using the following high-power LEDs for 3s: Group 1 ­ LEDX ­ T 2400, Orthometric; Group 2 ­ Flashmax P4 PRO Ortho, Rock Mountain Orthodontics; Group 3 ­ VALO CORDLESS, Ultradent; and Group 4 ­ conventional LED for 40s (control) POLY-WIRELESS, Kavo. The shear strength test was performed using a universal test machine (AME-2kN, Oswaldo Filizola, São Paulo, Brasil) with 0.5 mm/min speed and 50N load cell. The determination of statistical difference between the groups in relation to shear strength was performed using analysis of variance (ANOVA). The Kruskal-Wallis test was used to assess the IRA. RESULTS: Group 2 showed shear strength significantly higher than other high-power LEDs and was similar to conventional LED. Regarding ARI, there was a statistically significant difference between the groups and the only one that did not differ from the control group was 2, while the other high-power LEDs (Groups 1 and 3) had more adhesive failures between the resin and the enamel. CONCLUSION: There was a difference between the three types of third generation LED light curing agents, with greater shear strength and less adhesive failures observed in the LED that presented higher power. (AU)

Development of Proanthocyanidin-Loaded Mesoporous Silica Nanoparticles for Improving Dental Adhesion.

Dentin biomodification is a promising approach to enhance dental tissue biomechanics and biostability for restorative and reparative therapies. One of the most active dentin tissue biomodifiers is proanthocyanidin (PAC)-rich natural extracts, which are used in the dental bonding procedure in combination with resin-based adhesives (RBAs). This study aimed to investigate the use of mesoporous silica nanoparticles (MSNs) for the sustained delivery of PACs for dentin biomodification as a novel drug-delivery system for dental applications. The effects of the incorporation of MSN functionalized with 3-aminopropyltriethoxysilane (APTES) and loaded with PAC into an experimental RBA were assessed by characterizing the material mechanical properties. In addition, the immediate and long-term bonding performance of an experimental resin-based primer (RBP) containing MSN-APTES loaded with PAC was also evaluated. For that, different formulations of RBA and RBP were prepared containing 20% w/v MSN-APTES loaded with PAC before or after functionalization (MSN-PAC-APTES and MSN-APTES-PAC, respectively). The incorporation of MSN-APTES-PAC did not negatively impact the degree of conversion or the overall mechanical properties of the RBA. However, adding MSN-PAC-APTES resulted in inferior mechanical properties of the experimental RBA. In the adhesion studies, APTES-functionalized MSN was successfully added to an experimental RBP for drug-delivery purposes without compromising the bond strength to the dentin or the failure mode. Interestingly, the sequence of surface functionalization with APTES resulted in differences in the bonding performance, with better long-term results for RBP containing MSN loaded with PAC after functionalization.

Benzyldimethyldodecyl Ammonium Chloride Doped Dental Adhesive: Impact on Core's Properties, Biosafety, and Antibacterial/Bonding Performance after Aging.

Current dental adhesives lack antibacterial properties. This study aimed to explore the effect of incorporating benzyldimethyldodecyl ammonium chloride (BDMDAC) on the degree of conversion, contact angle, ultimate tensile strength (UTS), microtensile bond strength (µTBS), cytotoxicity, antibacterial and bonding performance after artificial aging. A dental adhesive was doped with BDMDAC in the concentration range of 1-5 wt.%. For antibacterial assays, the BDMDAC compound was subject to planktonic cells of Streptococcus mutans. Then, after incorporation into the dental adhesive, an S. mutans biofilm model was used to grow 48 h-mature biofilms. The biofilms grown over the formulated materials were assessed by colony-forming unit (CFU) counting assay and fluorescence microscopy staining. In addition, the cytotoxicity was evaluated. Samples were subjected to 10,000 thermal cycles for aging and evaluated by UTS, µTBS, and CFU. Incorporating BDMDAC did not increase the cytotoxicity or change the physical properties when the mass fraction of the BDMDAC was 1-5 wt.%. The UTS of BDMDAC-doped adhesives was not impaired immediately or over time. A significant bacterial reduction was obtained for the mass fraction of the BDMDAC greater than 3 wt.%. However, the BDMDAC-doped adhesives did not offer an antibacterial effect after artificial aging. The overall results indicate that the BDMDAC strategy has the potential to control of microbial growth of cariogenic planktonic cells and biofilms. However, other new technological approaches are needed to overcome the deleterious effect of BDMDAC release over time such as those based on the principle of drug delivery systems whereby the BDMDAC is transported on microparticles or core shells, providing tangible benefits to oral health over time.