Differences In Shear Bond Strength Values Research Articles

Comparing Various Resin Luting Cement Systems in Different Etching Modes Through Bond Durability and Morphological Features.

This study aimed to investigate bond performance of various resin luting cement (RLC) systems on enamel and dentin in different etching modes and to compare the RLC-tooth interface morphology using scanning electron microscopy (SEM). The self-adhesive RLC systems used in combination with universal adhesives were as follows: Scotchbond Universal Adhesive Plus + RelyX Universal (3M Oral Care) and Clearfil Universal Bond Quick ER + SA Luting Multi (Kuraray Noritake Dental). These RLC systems were also used alone as self-adhesive RLC systems without universal adhesives (self-adhesive mode). The conventional RLC systems for comparison materials were as follows: BeautiBond Xtream + ResiCem EX (Shofu) and Tooth Primer + Panavia V5 (Kuraray Noritake Dental). Twelve specimens were prepared for each group to measure shear bond strength (SBS) in different etching modes. A stainless-steel rod was used as a substitute for indirect restorations. Bonded specimens were allocated to baseline (stored for 24 hours) and artificially aged (thermocycling [TC] for 10,000 cycles) groups. Representative treated tooth surfaces and RLC-tooth interfaces were observed using SEM. Three-way analysis of variance (ANOVA) revealed that all the factors (etching mode, storage period, and RLC system) had a significant influence on the enamel SBS values (p<0.05). Enamel SBS was significantly higher in etch-&-rinse (ER) mode than in self-etch (SE) mode, regardless of RLC system or storage period. Three-way ANOVA showed that all the factors had a significant influence on the dentin SBS values (p<0.001). Most RLC systems showed significantly higher dentin SBS in SE mode than in ER mode, regardless of storage period. However, the combination with Scotchbond Universal Adhesive Plus and RelyX Universal showed no significant difference in SBS values between etching modes at the baseline and showed a significantly higher SBS value in ER mode than in SE mode after TC. The self-adhesive RLC systems with universal adhesives tended to show higher enamel and dentin bond performance than the self-adhesive RLC systems alone. The morphology of treated tooth surfaces and resin cement-tooth interfaces were dependent on the RLC system and etching mode used. The RLC systems with primer application showed a thin, high-density layer above the intact dentin in both etching modes, suggesting chemical interaction.

Self-etching primer versus hydrofluoric acid and air-abrasion: effects on flexural and resin bond strengths of resin-based CAD/CAM material

This study aimed to evaluate the effect of self-etching primer (Monobond Etch & Prime; MEP), hydrofluoric acid (HF), and air-abrasion (A) protocols on shear bond strength (SBS) of resin cement and flexural strength (FS) of nanoparticle-filled resin-based CAD/CAM material. Bar- and rectangular-shaped specimens (n = 130 for each) were obtained from a resin-based material (Cerasmart 270). The specimens were divided into 13 subgroups according to surface treatments: Control (C); HF for 60, 90, and 120 s; MEP for 60, 90, and 120 s; air-abrasion for 10, 15, and 20 s; air-abrasion followed by HF; air-abrasion followed by MEP; HF followed by MEP. Surface roughness (Ra) values were measured using a profilometer (Surftest SJ-210) by applying 9 readings per specimen. One specimen per group was examined by atomic force microscopy (AFM; Multimode 8) in a 20 μm × 20 μm area, and scanning electron microscopy (SEM; EVO LS-10) under ×1000 magnification. FS and SBS data were obtained using a universal test device (Marestek) at a crosshead speed of 1 mm/min. Air-abraded groups showed the highest Ra (A10: 1.331 ± 0.213; A15: 1.409 ± 0.110; A20: 1.491 ± 0.111; A + HF: 1.415 ± 0.138; A + MEP: 1.309 ± 0.071 μm) and the lowest FS values (A10: 122.59 ± 16.80; A15: 118.94 ± 11.74; A20: 117.22 ± 11.18; A + HF: 114.42 ± 18.09; A + MEP: 128.98 ± 19.74 MPa). FS values of HF- and/or MEP-applied groups were statistically similar to the control group (C: 167.37 ± 27.02; HF60: 186.74 ± 30.66; HF90: 162.79 ± 29.31; HF120: 184.11 ± 17.18; MEP60: 171.98 ± 29.65; MEP90: 162.49 ± 20.38; MEP120: 173.55 ± 22.50; HF + MEP: 175.09 ± 21.64 MPa). SBS values of MEP-applied groups were higher than those of HF-etched groups with the same duration. Significant differences in SBS values were found after etching protocols with different durations (HF60: 4.14 ± 0.64; HF90: 4.48 ± 0.33; HF120: 6.76 ± 1.65; MEP60: 6.24 ± 1.23; MEP90: 9.92 ± 1.25; MEP120: 10.22 ± 1.27 MPa). Prolonged MEP application (90 s and 120 s) can be the preferred surface treatment for resin-based CAD/CAM materials. However, air-abrasion may adversely affect its mechanical properties.

Comparative Evaluation of Shear Bond Strength, Adhesive Remnant Index and Cytotoxicity of Different Orthodontic Adhesives: An In-vitro Study

Introduction: Orthodontic adhesives should possess adequate bond strength and biocompatibility. Inadequate bond strength may lead to bond failures, and if the adhesive is not biocompatible, it may result in allergic reactions. Therefore, it is of prime importance to study the cytotoxicity and Shear Bond Strength (SBS) of commercially available orthodontic materials. Aim: This study aimed to comparatively evaluate in-vitro cytotoxicity, the Adhesive Remnant Index (ARI), and SBS of various orthodontic adhesives. Materials and Methods: This in-vitro study was conducted in an institutional setting as a collaborative effort between the Department of Orthodontics and White Lab-Blue Lab at Saveetha Dental College and Hospital, Chennai, India, from July 2023 to August 2023. Forty extracted human premolar teeth were bonded with four different ARI adhesives (U Bond, Enlight, Transbond XT, Aqualine LC) (n=10/group) and mounted on acrylic blocks. They were evaluated for SBS using a Universal Testing Machine (UTM), ARI using Scanning Electron Microscopy (SEM), and cytotoxicity using the MTT {3-(4, 5-dimethylthiazolyl2)-2, 5-diphenyltetrazolium bromide} assay on Human Gingival Fibroblast Cells (HGFC). Statistical analysis was performed using One-way ANOVA, with a post-hoc test for pairwise comparison to evaluate the SBS values, and the Kruskal-Wallis Test to analyse ARI inter group scores and cytotoxicity levels. Statistical Package for the Social Sciences (SPSS) software (Version 23.0) was used to conduct the statistical tests. Results: Significant differences in SBS values (p=&lt;0.001) and ARI scores (p=&lt;0.001) were noted between the different adhesives. No significant difference (p-value=0.534) in cytotoxicity was observed among all adhesives, with all exhibiting acceptable levels of biocompatibility. Conclusion: Primer-based adhesive (Transbond XT) demonstrated the highest SBS and ARI scores among the various orthodontic adhesives, with acceptable levels of biocompatibility. No significant difference was found between the conventional primer-based adhesive (Transbond XT) and the Single Component Adhesive (SCA) (Aqualine LC). Therefore, this study advocates for the use of SCA in routine clinical practice.

Atmospheric plasma treatment: an alternative of HF etching in lithium disilicate glass-ceramic cementation.

Objectives: This study aimed to investigate whether the atmospheric pressure plasma jet (APPJ) could modify the surface of lithium disilicate glass ceramics (LDC) instead of hydrofluoric acid (HF) in LDC resin cementation. Methods: Two hundred and thirty-two LDC blocks were randomly divided into seven groups: Group 1 (16 specimens) was the blank control group (without HF or APPJ treatment); Group 2 (36 specimens) was etched by HF; Groups 3-7 (36 specimens each) were treated with APPJ, and the relative air humidity (RAH) of the discharge was 22.8%, 43.6%, 59.4%, 75.2%, and 94.0%, respectively. Three LDC blocks in each group were characterized via X-ray photoemission spectroscopy (XPS) analyses, 3 blocks via contact angle measurements, and other 10 blocks via surface roughness measurements. The residual LDC blocks in groups 2-7 were cemented to composite cylinders. Testing the cemented specimens' shear bond strength (SBS) before and after thermocycling (6,500 cycles of 5°C and 55°C) revealed fracture patterns. Data were analyzed by ANOVA (post hoc: Bonferroni) (α = 0.05). Results: After APPJ treatment, the water contact angle values of APPJ treated blocks dropped from 31.37° to 5.66°, while that of HF etched ones dropped to 18.33°. The O/C ratio increased after HF etching or APPJ treatment according to the calculated results, except for the APPJ-treated samples at a RAH of 22.8%. The surface roughness of LDC blocks showed no statistic difference before and after APPJ treatment, but experienced significant difference after HF etching. The O/Si and O/C ratios varied after HF etching or APPJ treatment. No significant difference in SBS values could be found among groups 2-7 before or after artificial aging (p > 0.05). All specimens showed mixed failure patterns. Conclusion: The APPJ treatment method reported in this study is a promising novel strategy for surface modification of the LDC. With acceptable bonding strength, it might be an alternative to HF in LDC-resin cementation.

The Effect of Recommended Mouthwashes on the Shear Bond Strength of Orthodontic Brackets During the Covid-19 Pandemic: An In Vitro Study

Objectives: This study aimed to assess the impact of recommended mouthwashes (chlorhexidine, hydrogen peroxide, and povidone-iodine) used during the COVID-19 pandemic on the shear bond strength (SBS) of orthodontic brackets.&#x0D; Materials and Methods: A total of 52 human premolar teeth were divided into 4 groups (N=13) consisting of no intervention (control group), 0.2% chlorhexidine, 1.5% hydrogen peroxide, and 0.2% povidone-iodine. Following immersion in the mouthwashes, orthodontic brackets were bonded to enamel surfaces. Then, the brackets were debonded using a universal testing machine. The specimens were evaluated with a scanning electron microscope (SEM) and adhesive remnant index (ARI) score was assessed. One-way ANOVA and Tukey test were used for statistical analysis and P&lt;0.05 was considered significant.&#x0D; Results: The SBS of the experimental groups decreased compared to the control group. The highest SBS mean value was observed in the controls and the lowest was found in the 0.2% povidone-iodine group. Significant differences in SBS values were found between the 0.2% povidone-iodine group and the 1.5% hydrogen peroxide group when compared to the control group (P=0.023, P=0.028, respectively). SEM analysis revealed similar characteristics among the groups, with a closer resemblance between the chlorhexidine and control groups. Additionally, these groups exhibited greater etching depth compared to the other groups.&#x0D; Conclusion: Our findings highlight the importance of careful selection and application of mouthwashes in orthodontic procedures. While 1.5% hydrogen peroxide and 0.2% povidone-iodine may have some impact on bond strength, their use can still be considered acceptable within defined limits.

Bond strength of additively manufactured composite resins to dentin and titanium when bonded with dual-polymerizing resin cements

Statement of problemAdditively manufactured composite resins for definitive restorations have been recently introduced. The bond strength between these composite resins and different substrates has not been extensively studied. PurposeThe purpose of this in vitro study was to measure the shear bond strength (SBS) between additively manufactured composite resins and dentin and titanium substrates and compare those with the SBS between subtractively manufactured polymer-infiltrated ceramic and the same substrates (dentin and titanium), when different dual-polymerizing resin cements were used. Material and methodsOne hundred and eighty cylinder-shaped specimens (Ø5×5 mm) were prepared from 3 materials recommended for definitive restorations: an additively manufactured composite resin (Crowntec [CT]); an additively manufactured hybrid composite resin (VarseoSmile Crown Plus [VS]); and a subtractively manufactured polymer-infiltrated ceramic (Enamic [EN]) (n=60). Specimens were randomly divided into six subgroups to be cemented to the two substrates (dentin and titanium; n=30) with 1 of 3 resin cements (RelyX Universal, Panavia V5, and Variolink Esthetic DC) (n=10). The restoration surface to be bonded was treated according to the respective manufacturer’s recommendations. Dentin surfaces were treated according to the resin cement (Scotchbond Universal Plus Adhesive for RelyX Universal, Panavia V5 Tooth Primer for Panavia V5, and Adhese Universal for Variolink Esthetic DC), while titanium surfaces were airborne-particle abraded, and only the specimens paired with Panavia V5 were treated with a ceramic primer (Clearfil Ceramic Primer Plus). SBS was measured in a universal testing machine at a crosshead speed of 1 mm/min. Failure modes were analyzed under a microscope at ×12 magnification. Data were analyzed by using 2-way analysis of variance and Tukey honestly significant difference tests (α=.05). ResultsWhen SBS to dentin was considered, only restorative material, as a main factor, had a significant effect (P<.001); EN had the highest SBS (P<.001), while the difference in SBS values of CT and VS was not significant (P=.145). As for SBS to titanium, the factors restorative material and resin cement and their interaction had a significant effect (P<.001). Within each resin cement, EN had the highest SBS to titanium (P<.001), and within each restorative material, Variolink resulted in the lowest SBS (P≤.010). Overall, EN and RelyX were associated with the highest SBS to titanium (P≤.013). Mixed failures were predominant in most groups. ConclusionsRegardless of the substrate or the resin cement used, the subtractively manufactured polymer-infiltrated ceramic had higher shear bond strength than the additively manufactured composite resins. The SBS of the additively manufactured composite resins, whether bonded to dentin or titanium, were not significantly different from each other. Regardless of the restorative material, Variolink DC resulted in the lowest SBS for titanium surfaces.

Evaluation of the photodynamic therapy with riboflavin and curcumin on shear bond strength of orthodontic bracket: An in vitro study

Aim and objectivesThe aim of this study was to evaluate the effect of antimicrobial photodynamic therapy (aPDT) with riboflavin and curcumin on the shear bond strength (SBS) of the orthodontic brackets. Method and materialA total of 45 human premolar teeth were used in this study. All teeth were examined under a stereomicroscope. The samples were divided into 3 groups including no intervention (control group), aPDT with riboflavin and 460 nm LED and aPDT with curcumin and 460 nm LED. After aPDT procedure, orthodontic brackets were bonded to enamel surfaces. Then, the samples were thermocycled for 3000 cycles. The brackets were then debonded using a universal testing machine. The adhesive remnant index (ARI) score was assessed. ANOVA with Post-hoc test was used to compare the SBS values between groups. ResultsThe highest SBS mean value was presented in curcumin group (25.95±3.68) whereas, the lowest SBS mean value was observed in riboflavin group (22.19±4.73). The mode of failure was mostly score 1 and score 2 in all groups. There was no significant difference in SBS values and ARI score between groups. Scanning electron microscope images of the curcumin and control groups showed the honey comb structure, while the microscopic view of the riboflavin group lacked this structure and had less porosity and irregularity after etching. ConclusionRiboflavin and curcumin mediated antimicrobial photodynamic therapy both have acceptable bond strength of the orthodontic brackets and can be used before bonding to reduce inflammation and elimination of microbial biofilms.

Experimental composite containing silicon dioxide-coated silver nanoparticles for orthodontic bonding: Antimicrobial activity and shear bond strength.

ABSTRACTObjective: This study aimed to investigate the antimicrobial activity and shear bond strength (SBS) of orthodontic brackets to bovine enamel using experimental composites with different concentrations of silicon dioxide-coated silver nanoparticles (Ag@SiO2 NPs). Methods: Fifty bovine incisors were divided into five groups according to the composite (n = 10): G1 - Control Group (Transbond XT Resin), G2 - Experimental composite without Ag@SiO2 NPs; G3 - Experimental composite with 0.5% of Ag@SiO2 NPs; G4 - Experimental composite with 1% of Ag@SiO2 NPs; G5 - Experimental composite with 3% of Ag@SiO2 NPs. The SBS test was performed using a universal mechanical testing machine, and the adhesive remnant index (ARI) was analyzed by optical microscopy. For the antimicrobial activity evaluation, Streptococcus mutans (S. mutans) biofilm was formed for three days in hydroxyapatite discs. Posteriorly, S. mutans colony forming units (CFU) were evaluated. For SBS analysis, Analysis of Variance was used, followed by the Tukey test, at a 5% statistical significance level. The CFU data were analyzed by Kruskal-Wallis, followed by Dunn as a post-hoc test. The ARI results were analyzed descriptively. Results: There was no statistically significant difference in SBS values between the experimental and control groups (p>0.05). A 3% incorporation of Ag@SiO2 NPs statistically reduced the SBS values (p<0.05) compared to the 1% group. The addition of 3% of Ag@SiO2 NPs to the composites significantly reduced S. mutans biofilm formation, compared to group G2 (p<0.05). Conclusion: Composites incorporating 3% of Ag@SiO2 NPs presented similar SBS values compared to the control group, and showed significant antimicrobial activity.

Characterisation of the calcium silicate-based cement-composite interface and the bonding strength with total-etch or single/two-stage self-etch adhesive systems.

Due to favourable biological and physical properties, calcium silicate-based cements (CSCs) are biocompatible materials used widely for vital pulp therapies. Sealing efficacy between the adhesive system and CSC determines the clinical success of treatment. This study aimed to evaluate the shear bond strength (SBS) of CSC to composite resin with different adhesive systems and to analyse the CSC-composite interface. Mineral trioxide aggregate (MTA) (ProRoot MTA; Dentsply Tulsa Dental, Tulsa, OK), Biodentine (Septodont, Saint-Maur-des-Fossés, France) and NeoMTA Plus (Avalon Biomed Inc., Bradenton, FL) samples (n = 90) were placed in the cavities and divided into three subgroups according to the adhesive family (n = 10). SBSs were measured using a universal testing machine. The interfaces were examined using a scanning electron microscope (SEM) (×1000). NeoMTA Plus showed significantly higher SBS values than MTA and Biodentine (P < 0.0001). The application of total-etch adhesive system over Biodentine and NeoMTA Plus provided the statistically highest bond strength (P < 0.05). However, when the SBS values of MTA subgroups were compared, different adhesive families applied over MTA did not make a significant difference in SBS values (P > 0.05). Based on SEM analyses, the specimens exhibit no gaps, cracks or delamination within the adhesive layer, which indicates a good adhesion between the CSC-composite interface in all subgroups. In conclusion, the different adhesive families used over CSC did not influence interfacial gap formation.

A Comparison Between Phosphoric Acid- and Er:YAG Laser-Mediated Re-Etching of Enamel for Orthodontic Bracket Re-Bonding.

Objective: This study sought to compare enamel surface morphology and orthodontic bracket re-bonding strength after phosphoric acid- or erbium-doped yttrium aluminum garnet (Er:YAG) laser-mediated re-etching. Methods: A total of 81 extracted premolars were obtained from patients undergoing orthodontic procedures. Conventional etching with 35% phosphoric acid was first used to bond brackets to the enamel surface. Then brackets were de-bonded 1 week later. These samples were then separated randomly into three groups (n = 27 teeth each group) and re-bonded with new brackets after one of the following re-etching manners: Group A-35% phosphoric acid, Group B-Er:YAG laser (200 mJ, 30 Hz), and Group C-Er:YAG laser (250 mJ, 30 Hz). The enamel surface and the interface of enamel and adhesive were then analyzed through scanning electron microscopy. Shear bond strength (SBS) and adhesive remnant index (ARI) were also measured. Results: Samples in Group A exhibited significant residual adhesive at the enamel surface, whereas samples in Groups B and C showed a cleaner surface with more distinct and evenly distributed honeycomb-like structures. Further, samples in Group C displayed a larger average SBS value between the two laser-etching groups, although there were no significant differences in SBS values or ARI scores between the acid and laser re-etching groups (p > 0.05). Conclusions: Er:YAG laser-based enamel re-etching (250 mJ, 30 Hz) produces an uniform honeycomb-like structure and a trend of similar SBS compared with 35% phosphoric acid-mediated re-etching. Er:YAG laser-mediated re-etching seems to be a promising alternative approach for bracket re-bonding.

Does Double-layer Application of a Universal Adhesive Affect Its Bonding to Different Tooth Substrates?

Objective: evaluate the influence of single- or double-layer application of a universal adhesive on the bond strength to different tooth substrates. &#x0D; Methods: To Seventy-two extracted sound human teeth were used for the study. The teeth were divided into three groups according to tooth substrates; enamel, coronal and radicular dentin (n=24). The roots of the teeth were separated from the crowns and then abraded to obtain flat surfaces. The specimens were randomly allocated into 2 groups in accordance with application layers of universal adhesive (n=12). The universal adhesive, Adhese Universal was applied in self-etch mode as single- or double-layer (without light-curing of the first layer) to different substrates. Following the adhesive application, enamel, coronal- and radicular dentin substrates were restored with a resin composite (Tetric N-Ceram). The specimens were subjected to shear bond strength (SBS) test after storage in distilled water (37℃,24 h). Representative fractured and interface samples from each group were examined by a scanning electron microscope. The data were analyzed using two-way ANOVA(α = 0.05). &#x0D; Results: There was no statistically difference in SBS values between single- and double-layer applications of the tested universal adhesive on different dental substrates (p&gt;0.05). Whilst no difference was occurred between the different dental substrates in the single-layer application (p&gt;0.05), double-layer application on coronal dentin presented significantly higher bond strength than enamel (p

Effect of adhesive application method on repair bond strength of composite.

ObjectivesThis study aimed to evaluate the effect of the application method of universal adhesives on the shear bond strength (SBS) of repaired composites, applied with different thicknesses.Materials and MethodsThe 84 specimens (Filtek Z350 XT) were prepared, stored in distilled water for a week and thermocycled (5,000 cycles, 5°C to 55°C). They were roughened using 400-grit sandpapers and etched with phosphoric acid. Then, specimens were equally divided into 2 groups; Single Bond Universal (SU) and Prime&Bond Universal (PB). Each group was subdivided into 3 subgroups according to application methods (n = 14); UC: 1 coat + uncuring, 1C: 1 coat + curing, 3C: 3 coats + curing. After storage of the repaired composite for 24 hours, specimens were subjected to the SBS test and the data were statistically analyzed by 2-way analysis of variance and independent t-tests. Specimens were examined with a stereomicroscope to analyze fracture mode and a scanning electron microscope to observe the interface.ResultsAdhesive material was a significant factor (p = 0.001). Bond strengths with SU were higher than PB. The highest strength was obtained from the 1C group with SU. Bonding in multiple layers increased adhesive thicknesses, but there was no significant difference in SBS values (p = 0.255). Failure mode was predominantly cohesive in old composites.ConclusionsThe application of an adequate bonding system plays an important role in repairing composite resin. SU showed higher SBS than PB and the additional layers increased the adhesive thickness without affecting SBS.

In vitro testing of shear bond strength of orthodontic brackets bonded to different novel CAD/CAM ceramics.

Background. The present study aimed to evaluate the bond strength of metal bracket (MB) and ceramic bracket (CB) bonded to different CAD/CAM ceramic substrates etched with hydrofluoric acid (HFA) vs. phosphoric acid (PA). Methods. A total of 120 CAD/CAM ceramic blocks in 12 groups were fabricated from three different CAD/CAM ceramic materials: VITABLOCS Mark II, VITAENAMIC, and IPS e.max CAD. Each ceramic material group was divided into two etching groups: one treated with 9.5% HFA and the other treated with 37%. Sixty metal and CBs of the upper right central incisor were bonded to the HFA-treated blocks. Another 60 metal and CBs were bonded to the PA treated blocks. All the bonded specimens were thermocycled before shear bond strength (SBS) testing. Then the bond failure mode was recorded Results. There were no significant differences in SBS values between the three CAD/CAM ceramic materials. The HFA-treated specimens exhibited significantly higher SBS values than the PA-treated specimens. Also, the SBS values of CBs were significantly higher than the metal brackets (MBs). The adhesive remnant index (ARI) score was 4 for most of the groups, indicating that almost no adhesive remained on the porcelain surface. Conclusion. The CAD/CAM ceramic type did not influence SBS; however, HFA exhibited significantly higher SBS compared to PA.

Immediate enamel bond strength of universal adhesives to unground and ground surfaces in different etching modes.

The purpose of this study was to determine the immediate bond effectiveness of universal adhesives to unground and ground enamel surfaces in different etching modes, through shear bond strength (SBS) tests and scanning electron microscopy observations. Three universal adhesives, a conventional two-step self-etch adhesive, and a conventional single-step self-etch adhesive were compared. Human enamel specimens from lower anterior teeth were divided into four groups and subjected to the following treatments: (i) unground enamel in self-etch mode; (ii) ground enamel in self-etch mode; (iii) unground enamel in etch-&-rinse mode; and (iv) ground enamel in etch-&-rinse mode. Bonded assemblies were subjected to SBS testing. All the adhesives showed significantly higher SBS values in etch-&-rinse mode than in self-etch mode, regardless of whether enamel was unground or ground. The influence of the enamel surface condition on SBS was different in different etching modes. Without pre-etching, all tested materials showed lower SBS values in unground enamel than in ground enamel. In etch-&-rinse mode, no significant differences in SBS values were observed between unground enamel and ground enamel for any of the adhesives tested. Phosphoric acid pre-etching before application of self-etch adhesives to an unground enamel surface is essential to enhance initial enamel bond effectiveness.

An In Vitro Evaluation of the Effect of Various Adhesives and Surface Treatments on Bond Strength of Resin Cement to Polyetheretherketone.

To investigate the effect of various surface pretreatments and adhesive systems on bond strength of resin cement to polyetheretherketone (PEEK). 360 PEEK specimens were divided into 4 groups to receive the following pretreatments (n=90): no pretreatment, sandblasting, silica coating and Er:YAG laser. Surface roughness (SR) and scanning electron microscopy (SEM) evaluations were conducted after mechanical pretreatments for topographical surface evaluations. After the pretreatments, each group was divided into 3 subgroups (n=30) according to the adhesive system used: no adhesive system, Visio.link, and Signum PEEK Bond. Resin cement was applied, and specimens underwent 5000 thermocycles (5-55°C) before shear bond strength (SBS) test. One-way ANOVA and Tukey test were used to analyze the SR data; 2-way ANOVA and Fisher's LSD test were used to analyze the SBS data at the confidence interval of 95% (α=0.05). The sandblasting group demonstrated the highest SR values (p<0.05). No significant differences in SR values were identified among silica coating, laser, and control groups (p ˃ 0.05). Conditioning with Visio.link after sandblasting group exhibited the highest SBS values (p<0.05). No significant differences in SBS values were found between laser and control group (p ˃ 0.05). Conditioned groups presented higher SBS values than unconditioned groups (p<0.05). Between the two adhesive systems, Visio.link demonstrated statistically significant higher SBS values than Signum PEEK Bond (p<0.05). Silica coating and sandblasting were shown to provide superior pretreatment of PEEK surface. Laser pretreatments showed no effectiveness on bond strength of resin cement to PEEK. Adhesive systems improved the resin bonding to PEEK.

Effect of various bleaching treatments on shear bond strength of different universal adhesives and application modes.

ObjectivesThe aim of this in vitro study was to evaluate the bond strength of 2 universal adhesives used in different application modes to bleached enamel.Materials and MethodsExtracted 160 sound human incisors were used for the study. Teeth were divided into 4 treatment groups: No treatment, 35% hydrogen peroxide, 16% carbamid peroxide, 7.5% carbamid peroxide. After bleaching treatments, groups were divided into subgroups according to the adhesive systems used and application modes (n = 10): 1) Single Bond Universal, etch and rinse mode; 2) Single Bond Universal, self-etch mode; 3) Gluma Universal, etch and rinse mode; 4) Gluma Universal, self-etch mode. After adhesive procedures nanohybrid composite resin cylinders were bonded to the enamel surfaces. All specimens were subjected to shear bond strength (SBS) test after thermocycling. Data were analyzed using a 3-way analysis of variance (ANOVA) and Tukey post hoc test.ResultsNo significant difference were found among bleaching groups (35% hydrogen peroxide, 16% carbamid peroxide, 7.5% carbamid peroxide, and no treatment groups) in the mean SBS values. There was also no difference in SBS values between Single Bond Universal and Gluma Universal at same application modes, whereas self-etch mode showed significantly lower SBS values than etch and rinse mode (p < 0.05).ConclusionsThe bonding performance of the universal adhesives was enhanced with the etch and rinse mode application to bleached enamel and non-bleached enamel.

Orthodontic Metallic Lingual Brackets: The Dark Side of the Moon of Bond Failures?

Lingual orthodontics, among both young and adult patients, increased in popularity during last years. The purposes of the present investigation were to evaluate the shear bond strength (SBS) values and Adhesive Remnant Index (ARI) scores of different lingual brackets compared with a vestibular control bracket. One hundred bovine teeth were extracted and embedded in resin blocks. Four different lingual brackets (Idea, Leone; STB, Ormco; TTR, RMO; 2D, Forestadent) and a vestibular control bracket (Victory, 3M) were bonded to the bovine enamel surfaces and subsequently shear tested to failure utilizing a Universal Testing Machine. SBS values were measured. A microscopic evaluation was performed to obtain ARI scores. Statistical analysis was performed at a statistically significant level of p < 0.05 to determine significant differences in SBS values and ARI Scores. No statistically significant variations in SBS were reported among the different groups. Conversely, significant differences were shown in ARI scores among the various groups. Clinical relevance of the present study is that orthodontists can expect similar resistance to debonding forces from lingual appliances as with vestibular brackets.

Bond strength and interfacial morphology of orthodontic brackets bonded to eroded enamel treated with calcium silicate-sodium phosphate salts or resin infiltration.

To investigate the shear bond strength (SBS) of orthodontic brackets bonded to eroded enamel treated with preventive approaches and to examine the enamel/bracket interfaces. Ninety-one brackets were bonded to seven groups of enamel samples: sound; eroded; eroded+treated with calcium silicate-sodium phosphate salts (CSP); eroded+infiltrated by ICON®; eroded+infiltrated by ICON® and brackets bonded with 1-month delay; eroded+infiltrated by an experimental resin; and eroded+infiltrated by an experimental resin and brackets bonded with 1-month delay. For each group, 12 samples were tested in SBS and bond failure was assessed with the adhesive remnant index (ARI); one sample was examined using scanning electron microscopy (SEM). Samples treated with CSP or infiltration showed no significant differences in SBS values with sound samples. Infiltrated samples followed by a delayed bonding showed lower SBS values. All of the values remained acceptable. The ARI scores were significantly higher for sound enamel, eroded, and treated with CSP groups than for all infiltrated samples. SEM examinations corroborated the findings. Using CSP or resin infiltration before orthodontic bonding does not jeopardize the bonding quality. The orthodontic bonding should be performed shortly after the resin infiltration.

Shear bond strength of porcelain veneers rebonded to enamel.

In this laboratory research, shear bond strength (SBS) and mode of failure of veneers rebonded to enamel in shear compression were determined. Three groups (A, B, and C; n=10 each) of mounted molar teeth were finished flat using wet 600-grit silicon carbide paper, and 30 leucite-reinforced porcelain veneers (5.0 × 0.75 mm) were air abraded on the internal surface with 50 μm aluminum oxide, etched with 9.5% hydrofluoric acid, and silanated. The control group (A) veneer specimens were bonded to enamel after etching with 37% phosphoric acid using bonding resin and a dual cure resin composite cement. Groups B and C were prepared similarly to group A with the exception that a release agent was placed before the veneer was positioned on the prepared enamel surface and the resin cement was subsequently light activated. The debonded veneers from groups B and C were placed in a casting burnout oven and heated to 454°C/850°F for 10 minutes to completely carbonize the resin cement and stay below the glass transition temperature (Tg) of the leucite-reinforced porcelain. The recovered veneers were then prepared for bonding. The previously bonded enamel surfaces in group B were air abraded using 50 μm aluminum oxide followed by 37% phosphoric acid etching, while group C enamel specimens were acid etched only. All specimens were thermocycled between 5°C and 55°C for 2000 cycles using a 30-second dwell time and stored in 37°C deionized water for 2 weeks. SBS was determined at a crosshead speed of 1.0 mm/min. SBS results in MPa for the groups were (A) = 20.6±5.1, (B) = 18.1±5.5, and (C) = 17.2±6.1. One-way analysis of variance indicated that there were no significant interactions (α=0.05), and Tukey-Kramer post hoc comparisons (α=0.05) detected no significant pairwise differences. An adhesive mode of failure at the enamel interface was observed to occur more often in the experimental groups (B = 40%, C = 50%). Rebonding the veneers produced SBS values that were not significantly different from the control group. Also, no significant difference in SBS values were observed whether the debonded enamel surface was air abraded and acid etched or acid etched only.

Effect of Different Temporary Crown Materials and Surface Roughening Methods on the Shear Bond Strengths of Orthodontic Brackets

The aim of this study was to evaluate the effect of different temporary crown materials (TCMs) and surface roughening methods on the shear bond strength (SBS) of orthodontic brackets. TCMs are widely used during orthodontic treatment in teeth in need of prosthetic treatment, to prevent damage to the final restoration. However, there is no consensus considering the best method for roughening of the surface of TCMs. Five different TCMs [Dentalon Plus-(D), Basworth Trim II-(B), Voco Structure Premium-(V), 3M ESPE Protempt 4-(P), and Revotek LC-(R)] were used in this study. Different surface roughening methods (37% phosphoric acid, sandblasting, and Er:YAG laser) were employed in three subgroups (n=20). The SBS test was used to assess the durability of all groups. Scanning electron microscopy (SEM) analysis was performed on a representative specimen in each group. The highest mean SBS value was observed in group V, followed by groups D and P, regardless of the surface treatment. The lowest SBS values were observed in group B. The laser-irradiated groups had higher SBS values than the sandblasted and acid-etched groups. Furthermore, a significant difference in SBS values was observed between the laser-irradiated group V and all other groups (p<0.005). The effects of the chemical nature of TCMs on the SBS values appeared to be clinically negligible, whereas the type of surface treatments had a significant influence on bond strengths. Er:YAG laser irradiation caused a significant increase in bond strength between the TCMs and orthodontic brackets.