Er,Cr:YSGG laser irradiation influence on Y-TZP bond strength to resin cement

The aim of this study was to evaluate Y-TZP surface pretreatment with different protocols on microshear bond strength (μSBS) ceramic-cement interface. One hundred and sixty pre-sintered IPS e-max ZirCAD (Ivoclar-Vivadent) blocks were randomly divided into sixteen groups according to surface treatment (n=20): G1- no treatment (control); G2- ceramic primer; G3- tribochemical silica coating; G4- tribochemical silica coating+primer; G5- airborne particle abrasion (Al₂O₃); G6- airborne particle abrasion (Al₂O₃)+primer; G7- Er,Cr:YSGG laser; G8- Er,Cr:YSGG laser+primer. All specimens were sintered before surface treatment, except lasers groups, which were sintered after laser irradiation. Ceramic blocks were bonded with Panavia F resin cement (Kuraray, Okayama, Japan) (n=10) or RelyX ARC (3M ESPE, St. Paul, MN, USA) (n=10). The μSBS tests were carried out in a universal testing machine at a speed of 1mm/min after 24 h (n=5) or 6 months storage (n=5). Differences were found for both resin cements and storage conditions in relation to μSBS values (p<0.05). However, no significant difference for interaction between factors was observed in cemented blocks with RelyX ARC. Panavia F resin cement showed significant differences for interaction between factors (p<0.05). Laser treatment was not sufficient to increase μSBS values between Y-TZP and resin cements. Tribochemical silica coating followed by primer achieved the highest immediate μSBS values. The storage did not affect negatively μSBS values to both evaluated cements.     

The effects of water flow rate on shear bond strength of self etch resin cement to dentin surface after Er,Cr:YSGG laser etching

The aim of the present study was to evaluate the effect of water flow rate on the morphological features of dentin and shear bond strength (SBS) of self-etching resin cement after Er,Cr:YSGG laser etching. Dentin specimens obtained from extracted human third molars were randomly assigned to four groups (n = 23), including one that received no laser irradiation (control-group D) and three others with different laser parameters: 2.25 W, 50 Hz, 60% air with water flow rates of 19 mL/min-100% water (group A), 2.25 W, 50 Hz, 6.75 mL/min-50% water (group B), and 2.25 W, and 50 Hz, 2.75 mL/min-25% water (group C). The morphological features of each group were examined with scanning electron microscopy and atomic force microscopy. The SBS of resin cement disks (Panavia F2.0, Kuraray; Tokyo, Japan) (3 mm in diameter and 2 mm in height) to the dentin specimens was measured using a universal testing machine at a cross head speed of 0.5 mm/min. Bond strength values were analyzed with one-way ANOVA/Tukey tests. There were no significant differences between the SBS values of groups A and B (p > 0.05). However, the SBS values of these groups were significantly higher when compared to groups C and D (p < 0.001). Er,Cr:YSGG laser application with water flow rates of 6.75 or 19 mL/min resulted in better dentin surface alterations and increased the SBS of self-etching resin cement to dentin.     

Effects of cavity disinfectants on bond strength of an etch-and-rinse adhesive to water- or ethanol-saturated sound and caries-affected dentin

Objective: To evaluate the effect of cavity disinfectants on the immediate microtensile bond strength (μTBS) of an etch-and-rinse adhesive to water- and ethanol-saturated sound and caries-affected dentin (CAD). Material and Methods: Thirty-six human molars were sectioned to expose 1/3 of the mid-coronal dentin surface. Sound (n = 18) and CAD (n = 18) specimens were divided into six groups each (n = 3): one positive control (sound), one negative control (CAD), and five experimental groups each. In the control group, dentin surfaces were bonded using an etch-and-rinse adhesive with a traditional water-wet bonding technique. In the experimental groups, ozone was applied before etching and chlorhexidine after etching. In the ethanol-wet bonding groups, acid-etched dentin surfaces were treated with ethanol. Following adhesive application and composite buildups, bonded specimens were sectioned to form sticks. Failure modes were analyzed using a stereomicroscope. Results: The water-wet bonded sound control group yielded the highest μTBS among all groups (p < 0.001). The lowest μTBS values were observed in the ozone groups (p < 0.05). The ethanol-wet bonded CAD group exhibited a higher μTBS than the water-wet bonded negative controls. Although compared to the positive control, chlorhexidine decreased the μTBS (p < 0.05), an increase with no significant difference was observed in the negative control (p > 0.05). Conclusions: The μTBS values of CAD were lower than those of sound dentin. Ethanol-wet bonding improved the μTBS of CAD. Ozone application reduced the μTBS in both sound and CAD; chlorhexidine improved the immediate μTBS after etching in CAD.     

Effect of irradiation source on the dentin bond strength of a one-bottle universal adhesive containing an amide monomer

One-bottle universal adhesives have been widely used because of their simplicity of bonding procedures for various dental materials. The present study evaluated the effect of the polymerization light source on the micro-tensile bond strengths of a universal adhesive (Clearfil Universal Bond Quick) to dentin in comparison with a one-bottle self-etch adhesive (Clearfil S³ Bond Plus) and two 2-step self-etch adhesives (Clearfil SE Bond and Clearfil SE Bond 2). The adhesives were applied to extracted human dentin according to the manufacturer’s instructions and irradiated using either a quartz-tungsten-halogen (QTH) or blue light-emitting diode (LED). Subsequently, a resin composite was incrementally built on each adhesive and light-cured using the QTH. The bonded specimens were sectioned and subjected to micro-tensile bond strength tests. Both the type of adhesive and the light source were found to statistically affect the bond strength, with no interactions. The LED gave greater bond strength than the QTH. The bond strengths of the two-step adhesives were significantly higher than those of the one-bottle products, irrespective of the light source. The Clearfil Universal Bond Quick exhibited significantly higher bond strength than the Clearfil S³ Bond Plus. LED curing improved the performance of Clearfil Universal Bond Quick, and this product generated bond strength superior to that of the existing one-bottle adhesive Clearfil S³ Bond Plus.     

Effect of adhesive type and composite viscosity on the dentin bond strength

Objectives: Evaluate the influence of composite resins viscosity and type of cure of the adhesive systems on the bond strength of composite resins submitted to artificial aging.

Methods: Dentin specimens (n = 240) were divided into 2 groups: Group GC: GrandioSO, and Group GF: GrandioSO Heavy Flow. These groups were subdivided into 6: FM: Futurabond M – light cured, FDCC: Futurabond Dual Cure – chemical cured, FDCL: Futurabond Dual Cure – light cured, CS3: Clearfil S3 – light cured, CDCC: Clearfil Dual Cure – chemical cured, and CDCL: Clearfil Dual Cure – light cured. Resin blocks were build up on the dentin surface. Half of samples on each group were cut to obtain resin/dentin sticks (1 × 1 mm). The other half was first submitted to thermomechanical aging. The dentin/resin sticks were submitted to microtensile bond strength test and the results were analyzed using three-way ANOVA and Tukey’s test (α = 5%).

Results: ANOVA showed significant influence for adhesive (p = 0.0000) and aging (p = 0.0001). No significant influence of the composite viscosity on bond strength was observed (ANOVA: p = 0.0861). For adhesive, the results of Tukey’s test (MPa) were CDCC: 13.44 (±5.13)a; FM: 14,01 (±2.71)a; CDCL: 14.51 (±4.98)a; FDCC: 18.66 (±7.13)b; CS3: 18.80 (±6.50)b; FDCL: 19.18 (±7.39)b. For aging: AGED: 14.99 (±6.32)a; NOT AGED: 17.87 (±5.97)b.

Conclusion: Composite resin viscosities did not influence on the bond strength. Type of cure of the adhesives had influence on the bond strength. Thermomechanical aging decreased the bond strength.     

Effect of self-etching dual-curing universal adhesive system application on bond strength of dentin resinous liners dentin

Purpose: The aim of this study was to evaluate the influence of previous application of an adhesive system on bond strength of resinous liner materials to dentin. Methods: Ninety bovine incisors crowns had a 6 × 6 mm area of dentin exposed, with minimum of 2 mm thickness. They were embedded in acrylic resin, and the dentin was polished with P600 SiC sandpaper for 30 s to standardize the smear layer. The specimens were divided into 6 groups (n = 15) according to the application or not of a self-etching system (Futurabond U – Voco) and the type of resinous liner used: A+Ionoseal (adhesive and Ionoseal – Voco); Ionoseal (Ionoseal only); A+Vitrebond (adhesive and Vitrebond – 3M/ESPE); Vitrebond (Vitrebond only); A+Ionosit (adhesive and Ionosit – DMG) and Ionosit (Ionosit only). Adhesives were used following manufacturer’s instructions, and the liner materials were applied inside a 2-mm-depth matrix and light-cured for 20 s. The bond strength was measured by microtensile test, using a universal testing machine with a cross-speed of 1 mm/min. Data were analyzed using one-way ANOVA and Tukey’s test (p < 0.05). Results: The adhesive system application increased bond strength of all liners tested. Ionoseal presented the highest bond strength when the adhesive system was used and exhibited similar performance to Vitrebond without adhesive. Ionosit without adhesive showed the smallest bond strength compared with the other liners tested. Conclusion: The application of an adhesive system prior to the use of the resinous liners improved the bond strength to dentin and should be preconized.     

Bonding effectiveness of different dentin conditions on etch-and-rinse mode of two universal adhesives: the confocal laser scanning and shear bond strength

The purpose of this study was to evaluate the shear bond strength and the morphological differences of adhesive/dentin interface of two one-step universal adhesives to dentin using different dentin-conditioning methods with etch-and-rinse mode. Ninety-six dentin specimens were randomly divided into two groups based on application of two adhesives and assigned to three subgroups according to different dentin conditioning (wet-bonding; air-dried; rewetting). After etching and rinsing, experimental dentin conditioning was conducted on the etched dentin specimens. All specimens were subjected to shear bond strength testing using a universal testing machine, and all data were statistically analyzed using two- way analysis of variance with Tukey’s post hoc test. All debonded specimens were examined for fracture pattern by scanning electron microscopy (SEM). Adjunctively, one specimen per group was prepared by the same processing and longitudinally sectioned. Then, the infiltration ability of adhesives into dentin was examined by observing the interface using confocal laser-scanning microscopy (CLSM). Wet and Rewet groups exhibited significantly higher shear bond strength than dry groups on the etch-and-rinse system, regardless of different adhesives. The bond strength between wet and rewet groups showed no significant difference in Tukey’s test. Analysis of failure surface using SEM showed that predominant failure patterns were mixed in both the wet-bonding group and dry-bonding group. CLSM presented that resin penetration into etched dentin was enhanced similarly in wet and rewet group. Application of rewetting agents on dried dentin increased the bonding performance of universal adhesives on etch-and-rinse mode.     

Bond strength and adhesive interface analysis using EDTA as a dentin conditioner

This study evaluated dentin bond strength and dentin-resin interfacial morphology using phosphoric acid-etching and EDTA-conditioning. The occlusal enamel of twenty-four human third molars was removed to expose the dentin surfaces, which were polished with a SiC paper (600 grit). Teeth were randomly divided into three groups (n = 8): etching with 37% phosphoric acid (15 s), conditioning with 0.1 M EDTA (60 s) and 0.5 M EDTA (120 s). Adhesive (XP Bond, Dentsply) was applied and three layers (2 mm each) of composite (EsthetX, Dentsply) were placed and light-activated separately (20 s). Teeth were sectioned to obtain specimens for the microtensile bond strength test (1 mm² at cross section). Half of the specimens was tested in a universal testing machine (EZ Test, Shimadzu) after 24 h and the other half after storage for 10 months. Failure mode and adhesive interface were analyzed using scanning electron microscopy. Data were analyzed by mixed models for repeated measures (PROC MIXED) and Tukey-Kramer test, considering a significance level of 5%. Mean bond strength values (SD) after 24 h and 10 months were, respectively (in MPa): phosphoric acid: 37.3 (7.7) / 33.9 (6.7); 0.1 M EDTA: 14.7 (7.3) / 15.1 (10.1); 0.5 M EDTA: 25.1 (7.7) / 21.1 (14.1). Dentin treatment with EDTA and phosphoric acid resulted in hybrid layer and resin tags formation. Mixed failures were prevalent for all groups tested after 24 h. Storage for 10 months changed the failure mode for the 0.5 M EDTA group to adhesive failure (between dentin and bonding agent). EDTA applied for 60 s yielded lower bond strength results compared to phosphoric acid and EDTA (120 s), but there was no significant reduction after 10 months of storage for any of the tested groups.     

Effect of Er,Cr:YSGG laser surface conditioning on the adhesion of fiber- reinforced composite and zirconia intraradicular posts to the root dentin

This study evaluated the influence of Er,Cr:YSGG laser surface conditioning on push-out bond strength of different root posts to the root dentin. Extracted (N = 27, n = 9 per group) and endodontically treated human mandibular premolars were prepared to receive the posts. Three types of posts, namely quartz fiber (D), glass fiber (S), and zirconium dioxide post (C) were luted with resin cement. The posts were randomly assigned to one of the surface conditioning method: (a) No conditioning, control (L0), (b) Er,Cr:YSGG laser at 175 mJ, 3.5 W for 60 s (L1), and (c) at 225 mJ, 4.5 W for 60 s, with 60 μs pulse duration and repetition rate was 20 Hz (L2) irradiation. Six sections (two coronal, two middle, and two apical) were made in each tooth yielding to 1 mm thick specimens. The specimens were stored in distilled water at 37?°C for 24 h and push-out bond strength (MPa) was tested in a Universal Testing Machine (1 mm/min). Data were analyzed using Kruskall–Wallis and Dunns`s post hoc tests (α = 0.05). In group D, both laser treated groups (L1:16.16 ± 19.89; L2:8.24 ± 9.26) presented significantly less bond strength compared to control group (L0:28.3 ± 16.8) (p < 0.001). Mean push-out bond strength values did not significantly differ according to the root segments (coronal, middle, and apical) (p = 0.106). Application of Er,Cr:YSGG laser, with the parameters tested, did not increase the bond strength of zirconium glass fiber and zirconium oxide posts. Laser surface conditioning decreased the bond strength of quartz fiber posts in the root canal.     

Bond strength and durability of universal adhesive agents with lithium disilicate ceramics: A shear bond strength study

The aim was to assess the shear bond strength (SBS) of lithium disilicate (LD) ceramic to resin composite with different universal adhesives, duration of ageing and silane. One hundred and twenty LD ceramic discs were processed, fired and etched (HF acid 5%) for 20 s (sec). All specimens were divided into 12 groups (n = 10), based on different combinations of, 3 different universal adhesives [Scotchbond (SB) Universal Adhesive, All-Bond (AB) Universal, and Futurabond U (FU)], silane and different duration of ageing [24 h and 3 months]. Composite resin cylinders (Tetric ceram) (3mm × 2 mm) were formed using bonding jig on ceramic and were light-cured. The specimens in groups 1–6 and 7–12 were stored in distilled water (37 °C) for 24 h and 3 months (thermocycling -5000 cycles 5–55 °C/30 s dwell time) before being subjected to bond strength testing respectively. Using universal testing machine shear bond test was performed at a crosshead speed of 1 mm/min. Failure modes and fracture patterns were assessed using stereomicroscope and scanning electron microscope. Analysis of variance was performed to analyze data. SBS was significantly higher with silane than without silane (p < 0.01), regardless of the type of adhesive or storage duration. Specimens tested at 24 h storage showed significantly higher (p < 0.01) SBS than specimens tested after 3-months. A comparison among different universal adhesives showed significantly distinct bond strength (p < 0.01). Optimal bonds to LD were achieved by application of silane. While ageing through storage had a negative impact on the SBS, it varied among different adhesives.     

Effects of Er,Cr:YSGG laser on repair bond strength of 5-year water-aged and non-aged CAD/CAM ceramics

The aim of this study is to examine the repair bond strength of three different 5-year water-aged and non-aged computer-aided design/computer-aided manufacturing (CAD/CAM) ceramics (leucite-reinforced, lithium disilicate, and feldspathic ceramic) on which four different surface treatments (bur-grinding, sandblasting, acid-etching, and laser irradiation) have been applied with composite resin. Note that 360 ea. samples have been attained from CAD/CAM blocks. Each CAD/CAM ceramic has been randomly separated into two sub-groups depending on aging procedure. The designed 5-year water-aged and non-aged samples have been separated into four sub-groups. Ceramic surfaces were repaired then the samples have been placed into shear test device. Three-way variance analysis has been used in the comparison of the repair bond strengths depending on the ceramic type, surface treatment, and aging. Results have revealed that the repair bond strength values show differences depending on CAD/CAM ceramic type, surface treatment, and the aging of the surface (p < .001). While the aged and laser-irradiated feldspathic CAD/CAM ceramics showing the highest shear bond strength, the lowest shear bond strength values were in aged and bur-grinded feldspathic CAD/CAM ceramics. Irradiation with erbium chromium: yttrium scandium gallium garnet (Er,Cr:YSGG) laser has significantly increased the repair bond strength in leucite-reinforced and feldspathic CAD/CAM ceramics, acid-etching is suggested surface treatment for the lithium disilicate CAD/CAM ceramics.     

Effect of adhesive air-drying time on bond strength to dentin: A systematic review and meta-analysis

ObjectiveThe objective of this review was to evaluate the effect of air-drying time on the adhesion (bond) strength of adhesives to dentin in previously published studies and to conduct a meta-analysis to quantify the differences in the bond strength obtained after the different air-drying times.MethodsAn electronic search was performed using the Medline, Cochrane library, and Scopus databases. The included studies were laboratory studies that investigated the effect of adhesive air-drying time on adhesion (bond) strength of resin-based adhesives to coronal dentin. Studies which evaluated the effect of adhesives air-drying time on physical and mechanical properties of adhesives, interfacial properties, bond strength to root dentin, enamel, or bond strength of indirect composite restoration or orthodontic bracket, were excluded. The methodological quality of included studies was assessed. Meta-analysis was performed using Comprehensive Meta-Analysis software, version 2.0 (Biostat, Englewood, NJ, USA). The results of the meta-analysis were subjected to a further one-way analysis of variance, followed by the Tukey post hoc multiple comparison using R-software, version 3.4.3 (R Foundation for Statistical Computing, Vienna, Austria).ResultsThirteen studies fulfilled the inclusion criteria of this review, while only five studies were included in meta-analysis. The effect of adhesive air-drying time on the bond strength was significant in eight studies (61.5%), material-dependent in four studies (30.8%), and not significant in one study (7.7%). Eight studies (61.54%) presented a medium-risk of bias, three studies (23.08%) presented a low-risk of bias, and two studies (15.38%) presented a high-risk of bias. The analysis of micro-tensile bond strength (μTBS) of adhesives showed statistically significant difference between different air-drying times (p<0.05). The highest mean μTBS values were: 52.9 ± 11.38 MPa (obtained after air-drying of adhesives for 30 s), followed by 48.26 ± 9.77 MPa (15 s), and 37.76 ± 1.45 (25 s), while the lowest mean μTBS was 33.98 ± 2.30 MPa and 35.79 ± 6.63 MPa (5 s) obtained after 10 s and 5 s respectively.ConclusionThe air-drying time of adhesives is crucial to the adhesion strength to coronal dentin. Adhesive air-drying for shorter durations (5–10 s) may be insufficient to obtain adequately durable bonding to dentin, instead, Air-drying should be performed for longer durations (15–30 s), considering the pressure and distance of air-drying source.     

Influence of different surface treatments on zirconia/resin shear bond strength using one-bottle universal adhesive

ABSTRACT

This study was designed to evaluate the effect of different treatments on the zirconia/resin shear bond strength (SBS) using commercial one-bottle universal adhesive. Zirconia discs with different surface treatments (blank control; airborne-particle-abrasion; glazing) were bonded to the bovine enamel surfaces using one-bottle universal adhesive. All specimens were tested for SBS (MPa) before and after 10000 thermocycles. Statistically analysis were conducted by using one-way analysis of variance and multiple-comparison least significant difference tests (α = 0.05). Airborne-particle-abrasion group showed higher SBS (36.19 ± 11.86) than control group (14.98 ± 5.90) and glazing group (10.63 ± 5.39) (p < 0.05). After thermocycling test, the SBS significantly decreased for control group (8.84 ± 2.55) and glazing group (6.18 ± 2.78) while not for airborne-particle-abrasion group (41.5 ± 7.95). One-bottle universal adhesives combined with airborne-particle-abrasion showed quite high SBS of zirconia/resin, which was appropriate for bonding of zirconia restoration.     

Airborne-particle abrasion with niobium phosphate bioactive glass on caries-affected dentin: effect on the microtensile bond strength

This study evaluated the effect of airborne-particle abrasion with niobium phosphate bioglass (NbG) microparticles on the bond strength (μTBS) and longevity of an adhesive system to different dentin substrates. In this study, 18 Caries-free molars were used, of which 12 were microbiologically processed for caries induction. The dentin surfaces were evaluated in three groups: (1) Control – Healthy Dentin; (2) Partial removal of carious tissue; (3) complete removal of carious tissue. Half the teeth in each group were submitted to airborne-particle abrasion with NbG microparticles (15 s/1 cm/5 bar). After this, the adhesive Clearfil S³ was applied and composite buildups were constructed incrementally; and specimens were longitudinally sectioned to obtain bonded sticks (1.0 mm²) to be tested in tension (0.5 mm/min) immediately or after 6 months of storage in water. The fracture patterns were evaluated by stereomicroscope (40×) and then by scanning electron microscopy. The data were analyzed by the Kruskal-Wallis (post hoc Dunn) and Mann-Whitney tests (α = 0.05). Healthy dentin showed the highest bond strength (μTBS). Airborne-particle abrasion with NbG increased the μTBS values in the Group with complete caries removal. The bond strength values in the 24-h period were higher than those at 6 months. In the majority of the specimens the fracture mode was adhesive/mixed. The authors concluded that airborne-particle abrasion on dentin with NbG particles increased the μTBS in the group in which carious dentin was completely removed.     

Effect of erosive challenge and Nd:YAG laser irradiation on bond strength of adhesive systems to dentin

PurposeTo evaluate the effect of Nd:YAG laser irradiation and erosive challenge on bond strength of two adhesive systems to dentin.MethodsTwenty bovine incisors were cut and grounded to obtain eighty slabs of flat dentin. Specimens were allocated into eight groups, based on: adhesive system—a two-step etch-and-rinse and a two-step self-etch; laser irradiation—Nd:YAG (1 W/10 Hz) or control (no laser irradiation); and erosive challenge after restorative procedure—presence or absence of erosive challenge. Nd:YAG laser groups were submitted to laser irradiation before the restorative procedure. Blocks of composite resin were built up on the bonded surfaces with a Southern Dental Industries device to perform shear bond strength (SBS) test. After, each specimen of erosive challenge, groups were subjected to immersion in Sprite Zero^® (20 ml/2 h/24 °C/under agitation). The SBS test (0.5 mm/min) was performed after 24 h of water storage at 37 °C. Failure mode was evaluated with a stereomicroscope (X400). Data were analyzed with three-way ANOVA and Tukey’s post hoc tests (α=0.05).ResultsThe etch-and-rinse adhesive system presented higher bond strength values than self-etch adhesive. Laser irradiation increased the bond strengths values when erosive challenge was present. The predominant failure mode observed was adhesive.ConclusionsThe irradiation of Nd:YAG laser positively influences the bond strength values when erosive challenges are present. Moreover, the etch-and-rinse adhesive system is a better option to be used in dentin in this clinical condition.     

Incorporation of EGCG into an etch-and-rinse adhesive system: mechanical properties and bond strength to caries affected dentin

This study evaluated how a matrix metalloproteinase (MMP) inhibitor (EGCG) incorporated into an etch-and-rinse adhesive system (AS) affects the long-term microtensile bond strength (MTBS) to caries affected dentin (CAD) and flexural strength (FS) of AS. Forty CAD surfaces received acid conditioning and were randomly divided into four groups (n?=?10): EGCG-PRE – dentin treatment with 200?μg/mL EGCG solution; EGCG-INC – 200?μg/mL EGCG solution incorporated into SA; CHX-PRE – dentin treatment with 2% digluconate solution; NT – no treatment. The AS (Adper Single Bond 2, 3M ESPE) was applied and resin composite blocks were built on the dentin. Beam-shaped specimens (0.8?mm²) were obtained submitted to MTBS testing following 24?h, 6 months or 1 year of water storage (WS). Adhesive interface was analyzed by SEM. FS testing was performed by preparing specimens with the adhesive system, with or without the EGCG solution (200?μg/mL) (n?=?10). Tests were carried out in a universal machine (0.5?mm/min). MTBS data were submitted to two-way ANOVA and Tukey’s test, whereas FS data, to the Student’s t-test (α?=?0.05). MTBS values were not affected by EGCG application, either incorporated or used as a dentin treatment agent, regardless of the WS period; however, CHX negatively affected MTBS to CAD (p?<?0.001). WS significantly reduced MTBS values (p?<?0.001) from the 6-months time point. FS was not affected by EGCG incorporation into the SA (p?=?0.2527). EGCG incorporation into AS was unable to maintain bond stability to CAD over time, whereas it did not compromise adhesive’s property.     

Assessment of the initial and aged dentin bond strength of universal adhesives

This study evaluated the effect of mechanical loading on microtensile bond strengths (μTBS) of universal adhesives to dentin and quantified adhesive dentin penetration using micro-Raman spectroscopy. Human molars had occlusal dentin exposed and were allocated into eight groups: All-Bond Universal and Scotchbond Universal using etch-and-rinse and self-etch approaches, Adper Prompt L-Pop, Adper Single Bond Plus, Clearfil SE Bond, and Optibond FL. Following bonding procedures and build-ups, specimens were either stored in water at 37 °C for 24 h or mechanically loaded (50,000 cycles, 50 N) prior to μTBS test. Additional teeth were prepared for micro-Raman analysis of adhesive penetration and FE-SEM. Data were analyzed by two-way ANOVA and Tukey׳s post hoc test (P<0.05). Mechanical loading had no deleterious effect on μTBS with the exception of Adper Prompt L-Pop. Incomplete infiltration of the demineralized dentin was noticed for adhesives using the etch-and-rinse approach and for Scotchbond Universal in the self-etch approach.     

Efficacy of multi-mode adhesive systems on dentin wettability and microtensile bond strength of resin composite

Purpose: To evaluate the wetting ability and the microtensile bond strength of adhesive systems in various depths of dentin. Materials and Method: 48 extracted human molars cut in half in buccolingual direction. Buccal and lingual surfaces were used to obtain deep (n = 48) and superficial (n = 48) dentin. Groups were divided into 4 subgroups: Self-etch (CSE), etch&rinse (SB), multi-mode self-etch (SAU) and multimode etch&rinse (EAU) adhesive systems. 3 consecutive contact-angle measurements were obtained: T0- 3 μl drop of distilled water on dentin; T1-Droplet of the adhesive; T2- Distilled water after polymerization of the adhesive. After composite build-ups, microtensile measurements were performed. Contact angle data were analysed with analysis of variance for repeated measures. Bond strength data were analyzed by repeated measures analysis of variance, comparisons were made according to the logarithmic values (p < 0.05). Results: The difference between groups was not significant regardless of dentin depth for all measurements (p < 0.05). All groups except CSE enhanced the wetting ability of the adhesive but reduced the wetting ability of distilled water after application of the adhesive (p < 0.05). Regarding adhesive systems, the groups showed no significant difference between bond strengths to various depths of dentin except SAU (p > 0.05); in SAU, bond strength to deep dentine were significantly higher than superficial dentin (p < 0.05). Regarding adhesives’ bond strength, CSE showed significantly greater values than the other groups (p < 0.05). Conclusion: The cavity depth does not affect the bonding ability for all adhesive systems; self-etch adhesive systems might be a better choice since different adhesives may influence the wetting ability and microtensile bond strength of the dentin substrates.     

Alpha-hydroxy glycolic acid for root dentin etching: Morphological analysis and push out bond strength

The purpose of this study was investigated the use of α-hydroxy glycolic acid as a dentin etchant for adhesive procedures in the root canal. The etching pattern of glycolic acid and mineral content distribution of root canal dentin were assessed by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), respectively. The effect of glycolic acid surface etching on the push out bond strength of fiber post to root dentin was assessed using three adhesive systems: Single Bond Universal [SBU], Scotchbond Multipurpose [SBMP], and Ambar [AM]. The 37% phosphoric acid was used as a control group. The bond strength values were statistically compared using ANOVA/Fisher LSD tests (α = 0.05). SEM revealed similar etching patterns for phosphoric acid and glycolic acid. Both acids also shared similar interfacial morphology of the hybrid layer. EDS showed similar levels of Ca and Mg after treatment with glycolic acid when compared with phosphoric acid. When the P level was compared, it was observed that phosphoric acid caused greater removal of P. The push out bond strengths were statistically similar between glycolic acid and phosphoric acid in all groups (p > 0.05). Comparisons using post hoc Fisher LSD test showed that the bond strengths in the SBU and SBMP groups were not significantly different from each other (p > 0.05). The bond strength in the AM group was similar to that in the SBMP group (p > 0.05); however, it was significantly lower than that in the SBU group (p < 0.05). It can be concluded that the glycolic acid effectively etched root dentin surfaces, resulting in a surface pattern, hybrid layer, and push out bond strength similar to those produced by traditional phosphoric acid. Therefore, glycolic acid may be recommended as a suitable root dentin surface etchant for adhesive restorative procedures.     

Influence of the ER,CR:YSGG laser and different irrigation methods on push-out bond strength of fiber post

Er,Cr:YSGG lasers are currently being investigated for disinfecting the root canal treatment. The aim of this study was to compare the effects of various irrigation protocols on push-out bond strength of fiber posts. Fifty maxillary anterior teeth were divided into five groups (n = 10) according to the protocol that applied into the post space. Group-1: distilled water, Group-2: 5% NaOCl, Group-3: 2% CHX, Group-4: Er,Cr:YSGG laser (1.5 W, 20 Hz, 85 air, 75 water, 26.7 J/cm²), Group-5: Er,Cr:YSGG laser (1.25 W, 50 Hz, 34 air, 24 water, 12.7 J/cm²). Fiber posts were cemented with resin cement. The remaining part of the root, three slices were obtained from each specimen and push-out test was performed. One-way ANOVA and Duncan’s test at a 5% level of significance were used for the statistical analysis. Post space irradiation with Er,Cr:YSGG laser (1.5 W 20 Hz, 85 air, 75 water, 26.7 J/cm²) increases push-out bond strength of fiber post to root canal dentin. Further investigations are needed to establish and optimize ER,Cr:YSGG laser parameters to increase the push-out bond strength of fiber posts.