Self-etching Primer Research Articles

Effect of self-etch primer application on the bond failure rate of a mandibular bonded lingual retainer

BackgroundThe aim of this study was to examine the effect of self-etch primer (SEP) application on the bond failure rate of a mandibular bonded lingual retainer over 24 months.MethodsThe average age of the 86 individuals included in this study was 17 years 4 months. After the removal of the orthodontic appliances, the lingual retainers, which were made of six-stranded stainless steel wire, were bent and bonded onto the lingual surface of all mandibular anterior teeth. The study was performed using a split-mouth design. In the study group, the SEP was administered to the teeth’s lingual surfaces. In the control group, they were etched using 37% phosphoric etchant liquid gel. After etching, the primer was applied. The adhesive resin was applied and the retainer was fitted. The patients were re-evaluated over 24 months. The first bond failures and the amount of adhesive remaining on the tooth were recorded as the adhesive remnant index (ARI) scores. The chi-square test was used to compare the bond failure rates (P = 0.231) and ARI scores between the groups (P = 0.162). The survival rates of the retainers were estimated using the Kaplan–Meier test (P = 0.237). The significance level was P < 0.05.ResultsThe bond failure rates, ARI scores, and survival rates did not differ significantly between the groups.ConclusionsThe results of this study demonstrated that an SEP can be used successfully in mandibular lingual retainer bonding. In situations where saliva isolation is difficult, bonding a fixed lingual retainer with SEP is recommended.

An overview of dentin conditioning and its effect on bond strength

Given the inherent qualities of this medium, particularly when contrasted to enamel bonding, bonding to dentin is considered to be a less dependable approach. Further, when dentin is reduced, a sizable amount of cutting detritus coats the dentin's exterior, forming the smear layer. A steep decrease in interfacial adhesion over time has been attributed to the collagen web's inadequate resin impregnation as a result of the dentinal surface preparation with strong acidic agents like phosphoric acid, which left a zone of vulnerable collagen at the root of the hybrid smear layer. Self-etching priming agents that comprise acidic, non-cleansing, polymerizing monomers cause demineralization of the surface and encapsulate the collagen fibers and hydroxyapatite crystals while dissolving the smear layer or incorporating it into the adhesion interface. The concurrent occurrence of dentinal demineralization and monomeric penetration prevents collagen from buckling and shields an exposed collagen web. There may be a drawback to including the smear layer in the hybrid layer, according to certain investigations. Adhesion issues could arise even though the smear layer is reinforced with impregnated resin. To achieve dependable, robust resin-dentin connections, such defects may need to be removed by integrating a distinct etching process because they can reduce the resistance and longevity of the conjugated smear layer. In relation to a traditional bonding system, is has been discovered that removing the smear layer with 0.5 M ethylene diamine tetra-acetic acid (EDTA) before applying a self-etching primer result in greater bond strengths. Even though this approach integrates the smear layer within the adhesion interface, the pre-conditioning of dentin with just an acidic primer is highly convincing and merits additional exploration for the streamlined total-etching systems.

Ceramic Bonding Interface under Shear–Compression Stress: Ultra-High-Speed Imaging Contribution

The aim of this study is to visualize and characterize by ultra-high-speed imaging (UHSI) the failure phenomena at the resin–ceramic bonding interface of lithium disilicate (LiSi2) samples bonded with gold-standard protocol (Monobond Plus [MB]) and the nontoxic one (Monobond Etch & Prime [MEP]) subjected to mechanical loading. Unprecedented frame rate, image resolution, and recording time were reached by using the most advanced UHSI camera. The finite element analysis (FEA) of the proposed mechanical test confirmed that the specific design of our samples enables a combined shear and compression stress state, prone to test the bonding interface while being close to physiological stresses. Ten LiSi2 samples were pretreated by gold standard (MB, n = 5) and self-etching primer (MEP, n = 5). Axial compression loading gradually increased until catastrophic failure was performed. As shown by the FEA, the angle between the bonding interface and load direction leads to shear–compression stresses at the resin–ceramic bonding interface. Failure was recorded by UHSI at 300,000 fps. All recorded images were analyzed to segregate events and isolate the origin of fracture. For the first time, thanks to the image recording setup, it was observed that debonding is the first event before breakage, highlighting that sample fracture occurs by interfacial rupture followed by slippage and cohesive failure of materials. Failure mode could be described as mixed. MEP and MB showed similar results and behavior.

Evaluation of the Effect of Enamel Deproteinization Combined with a Self-etching Primer on the Adhesion of Orthodontic Brackets: An In Vitro Study

Aim:The study aimed to evaluate enamel deproteinization with sodium hypochlorite in the enamel conditioning using a self-etching primer for adhesion in orthodontic brackets.Background:The bonding in orthodontics plays a major role in the success of the treatment. The self-etching primers reduce the chair time and diminish the risk of saliva contamination.Methods:The sample comprised 80 bovines' incisors, divided into 4 groups according to the deproteinization process and adhesive system used: G1: enamel deproteinization + Transbond Plus self-etching primer + Transbond XT adhesive; G2: enamel deproteinization + 37% phosphoric acid + conventional primer + and Transbond XT adhesive; G3: Transbond Plus self-etching primer + Transbond XT adhesive; and G4: 37% phosphoric acid + conventional primer + Transbond XT adhesive. EMIC®DL 500 Universal Testing Machine was used for testing the shear bond strength of the samples.Results:Brackets bonded with self-etching primer showed greater adhesion force. The enamel deproteinization did not improve the bonding strength, regardless of the primer used.Conclusion:The deproteinization process does not improve the result of the adhesive bonding when using a self-etching primerin vitro.

Development of a remineralizing calcium phosphate nanoparticle-containing self-etching system for orthodontic bonding

ObjectivesThis study aimed to incorporate hydroxyapatite nanoparticles (nHA) or amorphous calcium phosphate nanoparticles (nACP) into a self-etch primer (SEP) to develop a simplified orthodontic bonding system with remineralizing and enamel preserving properties.Materials and MethodsnHA and nACP were incorporated into a commercial SEP (Transbond™ plus) in 7% weight ratio and compared with the plain SEP as a control. Shear bond strengths (SBS), enamel damage, and adhesive remnant index (ARI) scores were evaluated at 24 h and post 5000 thermocycling. Field-emission scanning electron microscope (FESEM) was used to inspect the distribution of the nanoparticles in the experimental SEPs and evaluate the enamel surface integrity both before bracket bonding and post bracket debonding. Phase determination and remineralizing capability of the modified SEP were characterized by X-ray diffraction and Raman spectroscopy, respectively.ResultsThe addition of nHA or nACP to the SEP significantly reduced the SBS, ARI, and enamel damage (p < 0.05) as compared to the control SEP; however, only nHA-SEP survived the thermocycling protocol and yielded acceptable SBS (13.38 MPa). Enamel remineralizing ability of the developed nHA-SEP was confirmed by both FESEM images and Raman phosphate map.ConclusionsIncorporating nHA into SEP resulted in clinically acceptable bond strengths with remineralizing ability.Clinical relevanceThe newly developed nHA-SEP has unprecedented ability to simultaneously etch, prime, and remineralize the enamel in a single step leaving immaculate enamel surface with the potential of saving cost and time at the post-debonding step.

Clinical bracket failure rates between different bonding techniques: a systematic review and meta-analysis.

Bracket failure increases the treatment time of orthodontic therapy and burdens patients with unnecessary costs, increased chair time, and possible new appointments. To compare the bond failures of different orthodontic materials based on the results of available clinical studies. A systematic search of clinical trials was performed in the Cochrane, Embase, and Pubmed databases with no limitations. The list of investigated techniques contained conventional acid-etch primer (CM-AEP), self-etch primer (SEP), self-cure resin (SCR), and simple or resin-modified glass ionomer (RM-GIC) materials and procedures. Clinical studies reporting the failure rate of bonded brackets after using direct adhesive techniques on buccal sites of healthy teeth were included. Bracket failure rates from eligible studies were extracted by two authors independently. Risk ratios (RRs) were pooled using the random-effects model with DerSimonian-Laird estimation. Thirty-four publications, involving 1221 patients, were included. Our meta-analysis revealed no significant difference in the risk of bracket failures between SEP and CM-AEP. After 6, 12, and 18 months of bonding, the values of RR were 1.04 [95% confidence interval (CI), 0.67-1.61], 1.37 (95% CI, 0.98-1.92), and 0.93 (95% CI, 0.72-1.20), respectively. At 18 months, bracket failure was 4.9 and 5.2% for SEP and CM-AEP, respectively. Heterogeneity was good or moderate (I2 < 42.2%). The results of RM-GIC at 12 months indicated a 57% lower risk of bracket failure using SCR as compared with RM-GIC (RR: 0.38; 95% CI, 0.24-0.61). At 18 months, bracket failures for SCR and RM-GIC were 15.8 and 36.6%, respectively (RR: 0.44; 95% CI, 0.37-0.52, I2 = 78.9%), demonstrating three to six times higher failure rate than in the case of etching primer applications. A major limitation of the present work is that the included clinical trials, with no exceptions, showed variable levels of risk of bias. Another possible problem affecting the outcome is the difference between the clustering effects of the split mouth and the parallel group bracket allocation methods. The results revealed no significant difference between SEP and CM-AEP up to 18 months after application. RM-GIC had much worse failure rates than acid-etching methods; additionally, the superiority of SCR over RM-GIC was evident, indicating strong clinical relevance. Prospero with CRD42020163362.

Effect of Surface-Etching Treatment, Glaze, and the Antagonist on Roughness of a Hybrid Ceramic after Two-Body Wear.

Stains and glaze are effective procedures for achieving an aesthetic smoothness on indirect restorations. Thus, the effect of surface-etching treatments previous to the stain layer and the glaze application on the occlusal and antagonist wear of a hybrid ceramic were evaluated against different antagonists. Disc-shaped samples were prepared from polymer-infiltrated ceramic network (PICN) blocks. The specimens were divided into eight groups, according to the surface-etching treatment and glaze application: P (polished specimens); PG (polishing plus glaze); E (hydrofluoric acid etching plus stain); EG (acid etching plus stain plus glaze); A (aluminum oxide sandblasting plus stain); AG (sandblasting plus stain plus glaze); S (self-etching primer plus stain); SG (self-etching primer plus stain plus glaze). Half of the samples were subjected to a wear simulation with a steatite antagonist, and the other half was tested using a PICN antagonist. The test parameters were: 15 N, 1.7 Hz, 6 mm of horizontal sliding, 5000 cycles. The discs and the antagonists’ masses were measured before and after the wear tests. The average roughness and spacing defects were evaluated. The etching treatment affected the surface and antagonist mass loss when tested against steatite. AG showed the highest mass loss. This influence was not detected when using the PICN antagonist. The glaze application after staining ensures a smoother surface and avoids antagonist wear.

Evaluation of Shear Bond Strength of Various Orthodontic Bracket Bonding Agents

Due to the development of properties of adhesive materials currently used in dentistry, the bonding ability between the brackets and the tooth enamel has been greatly improved. In general, in situations where cooperation can be obtained, adhesion of the orthodontic bracket through the conventional three-step process can show excellent bonding strength. However, if it is difficult to expect patient cooperation, as in the pediatric dentistry area, or if moisture isolation is not properly performed, the binding strength that does not reach the expected effect. As a result, various products that simplify the process for adhesion are being developed. The aim of this study was to evaluate and compare the shear bonding strength between the conventional 3-step adhesion system, self-etching primer system and one-step adhesion system that reduces the priming process. A total of 60 human maxillary, mandibular premolars were prepared. Group I (control group) were followed conventional 3-step bonding process. Group II were conditioned with self-etching primer. Group III were etched with 37% phosphoric acid and brackets were bonded with self-priming adhesive. The resultant shear bond strength of each group was measured and an adhesive remnant index (ARI) was recorded. The mean shear bond strength of group I, II, III were 14.69 MPa, 11.21 MPa and 12.21 MPa respectively. Significant differences could only be found between group I, II and group I, III (p &lt; 0.05). The ARI indicated no significant difference among all groups.

Comparison of shear bond strength of orthodontic brackets bonded to human teeth with and without fluorotic enamel: Asystematic review and meta-analysis of experimental in vitro studies.

The aim of this systematic review was to compare the shear bond strength (SBS) of orthodontic brackets bonded to human teeth with and without enamel fluorosis (EF) using conventional bonding interventions/techniques. An unrestricted search of indexed databases was performed with the following eligibility criteria: (a) human fluorotic teeth (experimental-group); (b) human teeth without fluorosis (control-group); (c) studies using phosphoric acid (PA) etching without air abrasion (AA), PA etching combined with AA, and application of self-etching primer (SEP) alone as bonding interventions/techniques and (d) measuring SBS in megapascals (MPa). Data screening, selection and extraction were performed by two reviewers. The risk of bias (rob) was assessed using the JBI Critical appraisal tool for Quasi-Experimental Studies. Meta-analyses were performed using a random effects model. The quality of available evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation approach. Ten in vitro studies were included. Subgroup analyses were performed for each intervention type. The SBS was significantly lower in fluorotic teeth when PA was used without AA (mean difference=3.26 MPa, confidence interval: [1.00, 5.52]); and there were no significant differences for the PA combined with AA and SEP interventions. All studies had a low rob. The overall level of evidence was at best low. The SBS is lower in teeth with EF when traditional PA is used. No significant differences were found in SBS between teeth with and without EF when PA is used with AA or when SEP is used alone.

Effect of Adhesive Resin Application on the Durability of Adhesion to CAD/CAM Glass-Ceramics after either Hydrofluoric Acid Etching or Self-etch Primer Application.

To evaluate the effect of two surface conditioning methods, namely conventional hydrofluoric acid vs self-etching primer, and the application of adhesive on the bond strength of resin cement to CAD/CAM glass-ceramics. Blocks (N = 96) (12 x 10 x 2.5 mm) were manufactured, 24 for each tested ceramic type: lithium silicate ceramic (LS), polymer-infiltrated ceramic (PIC), leucite-reinforced feldspathic ceramic (FD), and lithium-disilicate glass-ceramic (LD). For bond strength testing, 64 blocks were randomly divided into 16 groups (4 blocks per group) according to the following factors: ceramic: 4 levels; etching: 2 levels (HFS: hydrofluoric acid + silane or Monobond Etch & Prime [MEP]); and adhesive application: 2 levels, with (signified as A) and without. Then for each group, 15 resin cement cylinders (AllCem Dual, FGM) were built up. All specimens were subjected to thermocycling (10,000 cycles) and to shear bonding strength testing (SBS) (100 kgf, 0.5 mm/min). Mean shear stresses (MPa) were statistically analyzed by three-way ANOVA, Tukey's test, and Weibull analysis. The mean bond strength of group PIC-HFS-A (28.45 ± 7.6 MPa) was significantly higher than that of groups LS-HFS-A (12.11 ± 2.7MPa) and FDHFSA (20.86 ± 2.0MPa). Group PIC-HFS bond strength (25.02 ± 6.5 MPa) was significantly higher only when compared to group LS-HFS (15.82 ± 4.4 MPa). The LS group presented lower SBS compared to all other groups. No significant differences were found between HFS and MEP surface treatments. Surface treatment with MEP promotes adhesion similar to that of HFS. Additional application of adhesive after the surface treatments did not improve the bond strength.

Clinical evaluation of giomer- and resin-based fissure sealants on permanent molars affected by molar-incisor hypomineralization: a randomized clinical trial

BackgroundMolar-incisor hypomineralization (MIH) is a common condition among children that significantly increases the risk of caries. The objective of this research was to evaluate the clinical success of giomer- and conventional resin-based sealants applied on first permanent molars (FPMs) affected by MIH.MethodsOne-hundred FPMs with MIH which were indicated for non-invasive fissure sealant were selected in 39 children, aged 6–12 years. Using a split mouth design, the FPMs were randomized into two groups; Group 1. Resin sealant (etch-and-rinse + Conceal F) and Group 2. Giomer sealant (self-etch primer + BeautiSealant). Clinical evaluation was performed using the modified United States Public Health Service (USPHS) criteria at 1, 3, 6 and 12 months. The Log-rank, Fisher’s exact test and Kaplan–Meier analysis were used for statistical analysis.ResultsAt 12 months, the retention rates in Group 1 and Group 2 were 68% and %8, respectively (p = 0.000). The cumulative survival rates of conventional resin sealants were significantly higher than giomer sealants for all follow-up visits (p < 0.05). In Groups 1 and 2, the distribution of unsuccessful sealants on mandibular vs maxillary FPMs were 32.1% vs 31.8% (p = 0.612) and 91.7% vs 92.3% (p = 0.664), respectively. Although the success rate was higher for teeth with white opacities or lesions with less extension in Group 1, no significant difference was found. The average survival time was found as 10.46 ± 3.21 months in Group 1 and 4.02 ± 4.43 months in Group 2.ConclusionsThe conventional resin-based sealants yielded a better clinical performance over the 12-month evaluation period than the giomer sealants which were applied with self-etch primer. The high failure rate observed in giomer sealants could be explained by the possible deficiency in the etching capacity of self-etch primer on MIH-affected teeth.Trial registration ClinicalTrials.gov, NCT04929782. Registered 10 June 2021—Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT04929782.

A systematic review and meta-analysis of bond strength studies associated with self-etching primer and HF acid etching of dental glass-ceramics

ObjectiveThis review aims to provide a qualitative and quantitative evaluation of the effect of self-etching ceramic primer (SECP) on the resin–ceramic bond strength, as reported in published in-vitro studies. Materials and methodsThree databases (MEDLINE “PubMed”, Scopus and Web-of-Science) were electronically searched to identify studies that evaluated the effect of SECP on the bond strength to glass-ceramics versus the conventional treatment (hydrofluoric acid (HF) etching + silane-primer (S) application). Meta-analysis was conducted with RevMan version 5.4 software, Cochrane Collaboration; Copenhagen, Denmark using a random effect model, considering the bond strength evaluation after artificial aging. ResultsThirty-six studies satisfied the inclusion criteria for qualitative analysis, while only 18 studies were included in the quantitative analysis (meta-analysis). Twenty-three studies (63.9%) of the included studies showed a medium-risk of bias. The meta-analysis results showed no statistically significant difference (p ≥ 0.05) between resin-ceramic bond strength achieved following SECP or HF + S treatment with micro-shear bond strength (μSBS), tensile bond strength (TBS), and micro-tensile bond strength (μTBS) evaluation. However, shear bond strength (SBS) evaluation showed significantly less bond strength of SECP compared with HF + S (p < 0.00001). ConclusionSECP application can effectively promote adequate resin–ceramic bonding despite its mild etching capacity. However, more in-vitro studies that involve long-term clinically relevant artificial aging, and further clinical studies are required before SECP can be considered as an alternative to the conventional surface treatment (HF + S) of glass-ceramic materials.

Chemical and morphological characterization of self-etch primers incorporated with nanochitosan

This in vitro study evaluated experimental self-etch primers incorporated with different concentrations of nanochitosan gel (NC gel) and their action on the coronal and radicular dentin surface of bovine incisor teeth and the primer influence on the adhesive interface. Sections of 3 × 3 mm of coronal and root bovine dentin were flattened, and the smear layer was formed and standardized with 400 and 600-grit sandpaper. Root and coronal fragments (n=5) were treated with different primers: Clearfil™ SE Primer, Primer 1 – without NC gel, Primer 2–5% NC gel, Primer 3–10% NC gel, and Primer 4–15% NC gel. Primers were actively applied and left on the surface for 20 s. Images were acquired before treatment and immediately after primer application by confocal 3D laser scanning microscopy (x2160) to assess the degree of surface modification and dentinal tubule alteration. For adhesive interface analysis, dentin specimens (n=5) were treated with the evaluated primers, followed by the bond agent from Clearfil™ SE adhesive system, and restored with composite resin. Morphological analysis of the dentin surface and adhesive interface was performed using scanning electron microscopy (SEM) and chemical characterization using Fourier-transform infrared spectroscopy (FTIR). In coronal dentin, Clearfil™ SE Primer exposed fewer tubules than the experimental primers (p<0.05), and the percentage of open tubules was similar for all groups in root dentin (p>0.05). Primer 2 and Primer 3 showed higher values of perimeter and area for root dentin compared to the other groups (p<0.05), while Primer 1 was similar to Clearfil™ SE Primer (p>0.05). The incorporation of NC gel affected the behavior of the experimental primers. The addition of 10% of NC gel promoted a thicker and continuous hybrid layer with no gaps; however, higher concentrations of nanochitosan gel impaired the formation of a regular hybrid layer which is not favorable for an acceptable adhesion to the dentin substrate.

Adhesion to a Zirconia-reinforced Lithium Silicate Ceramic: Effects of Ceramic Surface Treatments and Resin Cements

This study had the objective to test the effect of ceramic surface treatments on the microshear bond strength (μSBS) of different resin cements to a zirconia-reinforced lithium silicate (ZLS). ZLS blocks were sectioned, embedded in acrylic resin, and then allocated into nine groups considering two study factors: "ceramic surface treatment" (HF - hydrofluoric acid; EP - self-etching primer; TBS - tribochemical silica coating) and "resin cements" (nMDP - without MDP monomer; MDP - with MDP monomer; SA - self-adhesive). Starch tubes (n=36) were placed on the treated ceramic surface and the cement was applied. Starch tubes were removed after 24 hours of storage, and the specimens were thermocycled (5,000×; 5°C-55°C). Next, the μSBS test was performed using the wire-loop technique, and topographic and failure analyses were performed. The factors "ceramic surface treatment" and "resin cement" statistically influenced the μSBS results. Considering the surface treatment factor, the TBS produced statistically lower values when the MDP resin cement was applied, being only similar to the MDP plus EP group. For the resin cement factor, no difference was found for nMDP and SA groups, apart from the surface treatments. Failure analysis showed that the groups treated with EP had a greater number of pre-test failures. The surface treatments induced noteworthy topographic alterations when compared to control (no treatment). The ZLS ceramic surface treatment with tribochemical silica coating associated with the MDP-containing resin cement resulted in lower bond strength values.

Effect of two hemostatic agents containing Aluminium chloride and ferric sulfate on bond integrity of resin-modified glass ionomer cement

ObjectiveTo evaluate the influence of hemostatic agents (Expasyl and Viscostat) on the bond values of RMGIC bonded to pretreated dentin surface with cavity conditioner (CC), self etch primer (SEP), and antimicrobial photodynamic therapy (aPDT) Materials and methodsOne hundred and eighty human third molars were embedded in a self-cure acrylic resin-filled polyvinyl cylinder. The dentinal surface was prepared and all the samples were arbitrarily distributed into three different groups liable to the hemostatic agent used (n = 60). Samples in group 1: no hemostatic agent used, Group 2: Samples exposed to Expasyl, and group 3: Viscostat. After applying the hemostatic agent, all the samples were surface treated with different surface conditioners. Subgroup A1, B1, C1 were conditioned with aPDT, Subgroup A2, B2, and C2 surface were treated with SEP, and Subgroup A3, B3, and C3 were smeared with CC. RMGIC was placed and SBS was assessed using a universal testing machine and failure mode analysis was performed using and stereomicroscope at 40x magnification. Analysis of variance (ANOVA) and Tukey's post hoc test compared the means and standard deviations (SD) following SBS testing (p = 0.05). ResultsHighest SBS was exhibited by group A2 (22.36 ± 1.66 MPa Control - SEP) whereas group A1 (14.14 ± 1.32 aPDT + Control) demonstrated the lowest SBS. Subgroups B1 (17.23 ± 0.33- Expasyl + aPDT) and C1 (18.36 ± 0.25 MPa -Viscostat + aPDT) were found to be comparable (p > 0.05). Similarly, A3 (19.69 ± 1.01- Control + CC) and B3 (18.23 ± 0.33 MPa- Expasyl + CC) and C3 (18.36 ± 0.37 Viscostat + CC) demonstrated no significant difference in bond scores (p > 0.05). Most of the failures in aPDT were adhesive. However, SEP and CC groups demonstrated admixed and cohesive failure ConclusionDentin conditioned by aPDT after hemostatic agents improves bond values of RMGIC. Self etch Primer and Cavity conditioner using polyacrylic acid without hemostatic agent improves bond integrity of RMGIC.

A multi-functional dentine bonding system combining a phosphate monomer with eugenyl methacrylate

ObjectiveThe tooth-resin composite interface is frequently associated with failure because of microbial contamination, hydrolytic and collagenolytic degradation. Thus, designing a dentine bonding system (DBS) with an intrinsically antimicrobial polymerisable monomer is of significance especially if it can be used with self-etching primers enabling resistance to degradation of the interface. MethodsExperimental adhesives were developed incorporating eugenyl methacrylate (EgMA) at concentrations of 0,10 or 20 wt%, designated as EgMA0, EgMA10 and EgMA20, respectively, for use as a two-step self-etch DBS with the functional monomer bis[2-(methacryloyloxy) ethyl] phosphate (BMEP) in the primer. The curing, thermal and wettability properties of the adhesives were determined, and hybrid layer formation was characterised by confocal laser scanning microscopy, microtensile bond strengths (µTBS) and nanoleakage by back-scattered SEM. In situ zymography was used to assess MMP inhibitory activity of the BMEP-EgMA DBS. ResultsEgMA in the adhesives lowered the polymerisation exotherm and resulted in higher Tg, without negatively affecting degree of conversion. Water sorption and solubility were significantly lower with higher concentrations of EgMA in the adhesive. The formation of a distinct hybrid layer was evident from confocal images with the different adhesives, whilst EgMA20 yielded the highest µTBS post water storage challenges and lowest nanoleakage after 6 months. The experimental DBS exhibited minimal to no MMP activity at 3 months. SignificanceThe hydrophobic nature of EgMA and high cross-link density exerts considerable benefits in lowering water uptake and polymerisation exotherm. The application of EgMA, adhesives in conjunction with BMEP in a multi-functional self-etching DBS can resist MMP activity, hence, enhance longevity of the dentine-resin composite interface.

Evaluation of Shear Bond Strength of a Primer Incorporated Orthodontic Composite Resin: An In-Vitro Study.

IntroductionNewer adhesive systems are available eliminating the separate priming step during the bonding procedure thereby reducing the chances of introduction of error during bonding. The purpose of this study was to compare the shear bond strength of a primer-incorporated adhesive with that of a self-etching primer system and conventional bonding system.Materials and methodSixty-six extracted human premolars were cleaned, mounted, and randomly divided into three groups. In group A (control), 22 teeth were bonded with stainless steel orthodontic brackets using the conventional bonding system; in group B, 22 teeth were bonded using a self-etching primer system (Transbond Plus SEP, 3M Unitek, Monrovia, CA) and in group C, 22 teeth were bonded using the new primer-incorporated adhesive system (GC Ortho Connect, GC Orthodontics, Breckerfeld, Germany). After bonding, the teeth were stored in artificial saliva at 37ºC for 24 hours and debonded with a universal testing machine. The adhesive remnant index (ARI) was also evaluated. Statistical analysis was done using one-way ANOVA to compare the shear bond strength values among the three groups and Kruskal Wallis test was used for comparison of ARI scores.ResultsThe SBS values in group A (11.60 ± 2.95 MPa), group B (9.44 ± 4.46 MPa) and group C (12.68 ± 6.25 MPa) were found to be comparable with no statistically significant difference. The ARI scores were also similar among the tested groups with the predominant site of bond failure being the bracket-adhesive interface indicating a safe bond-failure site.ConclusionGC Ortho Connect was found have clinically acceptable shear bond strength values that are comparable with that of self-etching primer and conventional bonding system. Therefore, it can be used effectively for saving the clinician’s chairside time by reduction in the number of steps during bonding without compromising on the bond strength.

Comparison of self-etch primers with conventional acid-etch technique for bonding brackets in orthodontics: a systematic review and meta-analysis.

Bonding with self-etch primers (SEPs) is one of the most popular systems for attaching orthodontic brackets to the enamel surface. There are conflicting reports about the efficacy and success of these systems compared with acid-etch (AE) bonding. This systematic review and meta-analysis was performed to compare SEP with conventional AE technique for bonding brackets in fixed orthodontics. Articles related to the subject of interest were searched in electronic databases, including PubMed, ISI Web of Science, Scopus, EMBASE, and Cochrane's CENTRAL, from inception to 2 June 2021. Search for grey literature, and hand search for relevant studies were also performed. Based on the PICO model, randomized clinical trials using full-arch bonded fixed orthodontic appliances comparing SEP and conventional AE systems were included in the review process. After assessing the risk of bias, data from the included studies were extracted using custom piloted forms. Inverse-variance random-effects meta-analyses were performed to combine the results of bracket failure, adhesive remnant index (ARI), and bonding time. Nineteen randomized clinical trials were included in the systematic review and 17 randomized clinical trials [5 parallel-group (PG) and 12 split-mouth (SM) studies] were included in the meta-analysis. No significant difference in bracket failure at 6 months [risk ratio (RR) = 1.50, P = 0.26, 12 SM] and (RR = 0.68, P = 0.34, 2 PG), 12 months (RR = 1.6, 8 SM) and (RR = 1.17, P = 0.54, 2 PG), and ≥18 months (RR = 0.84, P = 0.31, 3 SM) and (RR = 1.20, P = 0.3, 3 PG) between SEP and AE groups could be found. Also, ARI score was similar between different bonding systems [mean difference (MD) = -0.44, P = 0.06, 4 SM]. The bonding time per tooth was faster in the SEP group (MD = -26.55, P &lt; 0.001, 2 SM) and (MD = -24.00, P &lt; 0.001, 2 PG). inclusion of three studies with a high risk of bias and high amount of inconsistency between the results of individual studies were the biggest limitations of our review. The bracket bonding failure and ARI score were not significantly different between self-etch and conventional AE bonding systems. The bonding time was lower for the SEP, but some other requirements for SEPs like pumice prophylaxis could diminish this advantage. The protocol for this systematic review was registered at PROSPERO with the ID CRD42021248540.

Durability of resin bonding to lithium disilicate using different self-etching and conventional ceramic primers after long-term aging

ObjectivesTo evaluate the bonding durability after artificial aging provided by a self-etching and a no-etching ceramic primer compared to primers, which are applied by the etch and rinse method. MethodsLithium disilicate blocks were bonded to a composite resin (Clearfill Core, Kuraray) using 5 bonding methods (N = 24). Specimens of group MEP were bonded using a self-etching primer and the corresponding luting resin (Monobond Etch&Prime/Variolink Esthetic, Ivoclar Vivadent) Specimens of group UBE were bonded using a two-bottle silane solution (Universal Primer/Estecem, Tokuyama) without hydrofluoric acid ceramic etching. Specimens of the other 3 groups were bonded using etch and rinse bonding systems with prior hydrofluoric acid ceramic etching (MPV: Monobond Plus/Variolink Esthetic, Ivoclar Vivadent; SUR: Scotchbond Universal/RelyX Ultimate, 3 M; GML: G-Multi Primer/G-CEM LinkForce, GC). Each group was divided into 3 subgroups (n = 8) according to the storage conditions (3 days water storage (37 °C), 30 days water storage, 7,500 thermal cycles (5–55 °C) and 150 days water storage, 37,500 thermal cycles). The tensile bond strength (TBS) was measured and the data was statistically analyzed. ResultsAfter 3 days the median TBS ranged from 14.6 to 41.7 MPa, after 30 days from 4.2 to 39.0 MPa and after 150 days from 0 to 29.7 MPa. Both bonding systems utilizing a self-etching primer showed a significantly lower TBS than group MPV using a conventional ceramic bonding system. SignificanceEspecially after long-term storage with additional thermal cycling the bonding systems using primers without hydrofluoric acid ceramic etching do not provide a high bond strength.

The effect of multiple enamel conditioning on enamel micro-hardness

White spot formation is one of the common side effects in orthodontic treatments and multiple enamel conditioning might happen even during on session of fixed orthodontic treatments. The aim of the present study was to evaluate the impact of multiple enamel conditioning with different methods on enamel micro-hardness (MH). In this In vitro experimental study, the buccal surfaces of 105 extracted premolars were evaluated in seven groups: One control and six experimental groups. The enamel conditioning was performed in three ways: Etching with phosphoric acid 37%, etching with phosphoric acid 37% followed by primer application and conditioning with self-etch primer. The conditioning process in each way was also performed twice consecutively. The specimens were submitted in pH cycling model with demineralization and re-mineralization solutions for 14 days. Afterward Vickers MH test was applied with 0.981N force on the teeth for 10 s indentation time. Data were analyzed using One-Way ANOVA and Tukey HSD (honestly significant difference) test for multiple comparisons. A value of P < 0.05 was considered statistically significant. MH analysis showed statistically significant differences between the control group and the other conditioned groups (P < 0.05). The groups conditioned with acid-etch and primer, particularly twice, showed the lowest amount of MH in comparison to other groups. Self-etch primer had the least effect on MH of the enamel. Single time etching without using primer, made no considerable difference when compared to multiple etching. Etching process and covering the enamel with primer decrease enamel MH. Using self-etch primer is a more conservative method of enamel conditioning.