Adhesive Bond Strength Research Articles

The effect of curing mode of dual-cure resin cements on bonding performance of universal adhesives to enamel, dentin and various restorative materials.

The effect of curing mode of dual-cure resin cements on the tensile bond strength (TBS) of universal adhesives to enamel, dentin, zirconia, lithium disilicate ceramics (LDS), feldspathic porcelain (FP), and a Pd-Au alloy was evaluated. The substrates were bonded using Tokuyama Universal Bond (TUB) or Scotchbond Universal Adhesive (SBU), followed by luting with Estecem II (ECII) or Rely-X Ultimate (RXU), respectively, which were used either in light-curing or self-curing mode. The TBS test was performed after 24 h or 5,000 thermal cycles. Light-curing significantly improved the 24-h TBS of TUB/ECII to enamel, dentin and FP, as well as the TBS of SBU/RXU to all substrates except LDS. After thermal cycling, light-curing significantly increased the TBS of both adhesives/cements to dentin, but significant differences between curing modes were seldom observed for other substrates. This suggested that light-curing is essential for the hydrophilic dentin, but self-curing might be sufficient for other substrates.

Influence of beam homogenization on bond strength of adhesives to dentin

ObjectiveThis study evaluated the effect of beam homogeneity on the microtensile bond strength (μTBS) of two adhesive resins to dentin. MethodsOne polywave light-emitting-diode (LED) LCU (Bluephase Style, Ivoclar Vivadent AG) was used with two different light guides: a regular tip (RT, 1010 mW/cm2 emittance) and a homogenizer tip (HT, 946 mW/cm2 emittance). The emission spectra and beam profiles were measured from both light guides. Extracted third molars were prepared for μTBS evaluation using two adhesive systems: Excite F (EXF) and Adhese Universal (ADU). Bond strength was calculated for each specimen (n = 10) at locations that correlated with the output of the two LED chips emitting blue (455 nm) and the one chip that emitted violet light (409 nm) after 24-hs and after one-year water-storage. The μTBS was analyzed using a four-way analysis of variance (factors: adhesive system, light guide, LED wavelength, and storage time) and post-hoc Tukey test (α = 0.05). ResultsEXF always delivered a higher μTBS than ADU (p < 0.0001), with the μTBS of ADU being about 20% lower than EXF. The light guide (p = 0.0259) and storage time (p = 0.0009) significantly influenced the μTBS. The LED wavelengths had no influence on the μTBS (p > 0.05). SignificanceHomogeneity of the emitted light beam was associated with higher 24-h μTBS to dentin, regardless of the adhesive tested. Also, differences in the composition of adhesives can affect their compatibility with restorative composites and their ability to maintain bonding over one year.

Strength development and deterioration mechanisms of foamed asphalt cold recycled mixture based on MD simulation

The recycling and reuse of asphalt pavement have become requirements for environmental protection. Foamed asphalt cold-recycling technology is drawing extensive attention and being widely applied. Foamed asphalt cold recycled mixture has advantages such as energy savings, reduced asphalt content, and low transportation costs, and it has the characteristics of both rigid and flexible pavement. However, foamed asphalt mixtures are complex in composition, as it includes recycled asphalt pavement (RAP), water, new asphalt, aggregate, and cement. Therefore, the interaction mechanisms between recycled asphalt pavement and cement or foamed asphalt within the presence of water in the mixing, curing and service procedures will play a key role in determining the development and deterioration of strength of foamed asphalt cold recycled mixture, which was however not well clarified. This study firstly specified the decrease of strength of foamed asphalt cold recycled mixture when considering the effect of water in field project. It was found that the strength of foamed asphalt cold recycled mixture increased along with the decrease of water content during the curing procedure, and decreased by 15–20% through the winter frost. Then the interaction between RAP and cement or foamed asphalt within and without the presence of water had been analyzed with molecular simulation method. The mechanisms of strength development and deterioration of foamed asphalt cold recycled mixture were clarified from the point of view of molecular interaction. The simulation results indicate that the adhesion strength between RAP and cement is greater than that between RAP and new asphalt. The presence of water simultaneously weakens the adhesive bond strengths between RAP and cement and RAP and asphalt.

Influence of disinfection of caries effected dentin with different concentration of silver diamine fluoride, curcumin and Er, Cr:YSGG on adhesive bond strength to resin composite.

The aim of the study was to determine the effect of various disinfectants (CP, MB, 3.8 % SDF, 38 % SDF and ECL) on caries affected dentine (CAD) and its bond strength to composite restoration MATERIAL AND METHODS: Fifty carious mandibular teeth were collected based on the criteria of ICDAS (International Caries Detection and Assessment system). Specimens up to cement enamel junction were fixed in poly vinyl pipes. All caries molars were grinded using silicon grinding carbon disk and randomly assigned into five groups based on disinfecting regimes (n = 10). Group 1, Caries affected dentin (CAD) treated with MBP [100 mg/L]; Group 2, CAD treated with Curcumin photosensitizer (CP) [500 mg/L]; Group 3, CAD treated with 3.8 % SDF Group 4, CAD treated with 38 % SDF and group 5 sterile with Er,Cr:YSGG (ECL).Self-etch adhesive bond was smeared over the surface of all specimens followed by application of composite incrementally and light cured. Samples were debonded in a universal testing machine and shear bond strength (SBS) was noted in MegaPascal (MPa). The debonded surfaces were evaluated under stereomicroscope to determine the failure mode. For inter group comparison analysis of variance (ANOVA). Tukey HSD was applied for multiple group comparison. The significance level was kept at p < 0.05 RESULTS: The maximum bond strength was observed in group 2 CAD disinfected with CP (17.57 ± 0.85 MPa). Whereas, minimum bond strength values were presented by group 3 CAD disinfected with 38 % SDF (11.14 ± 0.29 MPa). CAD treated with MBP (14.21 ± 0.22 MPa) was comparable to group 5 (p > 0.05). Similarly, group 2 was found to be comparable to group 4 CAD disinfected with 3.8 % SDF (16.22±0.53 MPa) (p > 0.05). 3.8 % SDF and PDT with CP have shown potential to be adopted for dentin disinfection treatment without adversely affecting bond strength of CAD to composite resin.

Experimental investigation and study of HVOF sprayed WC-12Co, WC-10Co-4Cr and Cr3C2-25NiCr coating on its sliding wear behaviour

An experimental investigation followed by a comparative study of HVOF sprayed WC-12Co, WC- 10Co4Cr and Cr3C2-25NiCr coatings were conducted at three different loads of 20, 40 and 60 N. Sliding wear of coated specimens against hardened EN-32 disc was performed as per the G 99–5 standard at room temperature. The feedstock powders and corresponding coatings were characterized for microstructural studies along with porosity, microhardness, and adhesive bond strength. The experimental results suggest that the stability of the transfer layer plays a significant role in stable wear. The WC-12Co coating shows the best sliding wear resistance, maximum microhardness which was found to be 56.6% and 9.6% higher than WC-10Co-4Cr and Cr3C2-25NiCr coatings. The maximum adhesive bond strength was found to be 2.03% and 10.5% higher in WC-12Co than WC-10Co-4Cr and Cr3C2-25NiCr. Tribo oxide layer counterbalances to stabilize the wear during high heat generation at higher loads. Various aspects and mechanisms of these improvements are discussed in this paper.

Hierarchical Surface Texturing of Hydroxyapatite Ceramics: Influence on the Adhesive Bonding Strength of Polymeric Polycaprolactone.

The tailored manipulation of ceramic surfaces gained recent interest to optimize the performance and lifetime of composite materials used as implants. In this work, a hierarchical surface texturing of hydroxyapatite (HAp) ceramics was developed to improve the poor adhesive bonding strength in hydroxyapatite and polycaprolactone (HAp/PCL) composites. Four different types of periodic surface morphologies (grooves, cylindric pits, linear waves and Gaussian hills) were realized by a ceramic micro-transfer molding technique in the submillimeter range. A subsequent surface roughening and functionalization on a micron to nanometer scale was obtained by two different etchings with hydrochloric and tartaric acid. An ensuing silane coupling with 3-aminopropyltriethoxysilane (APTES) enhanced the chemical adhesion between the HAp surface and PCL on the nanometer scale by the formation of dipole–dipole interactions and covalent bonds. The adhesive bonding strengths of the individual and combined surface texturings were investigated by performing single-lap compressive shear tests. All individual texturing types (macro, micro and nano) showed significantly improved HAp/PCL interface strengths compared to the non-textured HAp reference, based on an enhanced mechanical, physical and chemical adhesion. The independent effect mechanisms allow the deliberately hierarchical combination of all texturing types without negative influences. The hierarchical surface-textured HAp showed a 6.5 times higher adhesive bonding strength (7.7 ± 1.5 MPa) than the non-textured reference, proving that surface texturing is an attractive method to optimize the component adhesion in composites for potential medical implants.

Recent progresses and applications in laser-based surface texturing systems

Laser surface texturing is a relatively well-known technique for enhancing the surface topography of engineering materials. Lately, several surface texturing approaches like nanosecond, picosecond and femtosecond laser texturing have been adopted for surface modification and to study the deterministic behaviours of texturing patterns with different shapes and sizes. Due to superior texturing accuracy and flexibility, laser surface texturing has been used to enhance lubrication and wear behaviour, mechanical interlocking at coating substrate interface, and creating superhydrophobic surfaces. The present paper review aims to discuss the recently enhanced tribological aspects using laser surface texturing for engineering surfaces. This study has highlighted the different laser surface texturing processes and future directions of surface modification to enhanced adhesion bond strength in surface coatings, improved lubrication for surface contact, and fabrication of superhydrophobic surfaces.

Microtensile bond strength of Resin composite to Normal dentin and Caries - affected dentin with total-etch and self-etch bonding adhesives before and after thermocycling

Objectives: To measure the microtensile bond strength of total-etch and self-etch adhesives to intact and caries affected dentin. To check the effect of thermal cycling on the bond strength of these adhesives to caries affected and intact dentin. Materials and Methods: Thirty extracted carious human molars were assigned to two groups according to adhesive used i.e Adper Single Bond (Total etch) with P90 (Self-etch). The occlusal surface of teeth will be sectioned to expose dentin and built up with Filtek 90 composite (3M) to a 3 mm height. The teeth were then sectioned to obtain rods of 6mm length and 1mm width and 1 mm depth with dentin-composite interface located at the centre. The specimens were examined under microscope to separate caries–affected dentin and unaffected dentin into two groups. Half the specimens from each group were subjected to 3000 thermo cycles (5 deg Celsius to 55 deg Celsius). All specimens were subjected to microtensile bond strength testing in a special apparatus attached to the Universal testing machine. Results were recorded and data was statistically analyzed with Students unpaired ‘t’ test. Results: Students ‘t’ test showed that the values had a statistically significant difference observed between total etch (T.E) i.e. Adper Single Bond 2 and self etch (S.E) i.e. P 90; caries-affected dentin (CAD) and normal dentin (ND); with thermocycling and without thermocycling. Interpretation and Conclusion: The present study concludes that total-etch has a higher bond strength compared to self-etch. Bond strengths are higher to normal dentin than caries-affected dentin. Thermocycling lowers the bond strength values of all the groups.

Effect of Air-Blowing Time on The Microshear Bond Strength of Two Universal Adhesives to Enamel and Dentin

Objectives: The aim of this study was to investigate the effect of air blowing time on the microshear bond strength of two universal adhesives to enamel and dentine. Materials and methods: Thirty extracted sound human molars were used. Flat enamel and dentin surfaces were obtained by removing the buccal enamel surface of each tooth exposing the buccal enamel and dentin. The teeth were randomly divided into two equal groups (N= 15) according to the tested adhesive system either Single Bond Universal (SBU) or all bond universal (ABU). Each group was further divided into 3subgroups (N= 5) according to the air blowing time i.e (5 seconds, 10 seconds, and 15seconds). Each subgroup was further subdivided into two divisions according to the substrate either enamel or dentin. Each substrate received 2 resin composite microrods (N=10). After storage in distilled water (37°C/24 h), microshear bond test was performed in a universal testing machine. One-way ANOVA followed by Tukey post-hoc test was used to compare between more than two groups in non-related samples. Two-way ANOVA was used to test the interaction between different variables. Results: There was a statistically significant difference between (15sec), (10sec) and (5sec) groups for (SBU) and (ABU) in enamel (p≤ 0.001). There was also statistically significant difference between (15sec), (10sec) and (5sec) groups for (SBU) and (ABU) in dentin (p <0.001). Conclusions: Air blowing time of 15 seconds in enamel has a positive effect on microshear bond strength of universal adhesives. Air blowing time effect in dentin was material dependent.

Effects of Zn-Doped Mesoporous Bioactive Glass Nanoparticles in Etch-and-Rinse Adhesive on the Microtensile Bond Strength.

The purpose of this study was to assess the effects in the dentin bond strength of dental adhesives (DAs) and biological effects using zinc (Zn)-doped mesoporous bioactive glass nanoparticles (MBN-Zn). Synthesized MBN and MBN-Zn were characterized by scanning electron microscopy (SEM), X-ray diffraction and the Brunauer, Emmett and Teller (BET) method. The matrix metalloproteinases (MMP) inhibition effects of DA-MBN and DA-MBN-Zn were analyzed. The microtensile bond strength (MTBS) test was conducted before and after thermocycling to investigate the effects of MBN and MBN-Zn on the MTBS of DAs. The biological properties of DA-MBN and DA-MBN-Zn were analyzed with human dental pulp stem cells (hDPSCs). Compared with the DA, only the DA-1.0% MBN and DA-1.0% MBN-Zn exhibited a statistically significant decrease in MMP activity. The MTBS values after thermocycling were significantly increased in DA-1.0% MBN and DA-1.0% MBN-Zn compared with the DA (p < 0.05). It was confirmed via the MTT assay that there was no cytotoxicity for hDPSCs at 50% extract. In addition, significant increases in the alkaline phosphatase activity and Alizarin Red S staining were observed only in DA-1.0%MBN-Zn. These data suggest the 1.0% MBN and 1.0% MBN-Zn enhance the remineralization capability of DAs and stabilize the long-term MTBS of DAs by inhibiting MMPs.

Improvement of the adhesive strength of adhesion bonds of textile products for the increasement of the efficiency of criminalistic support of law enforcement activities

Analysis of methods of chemical and physical modification and activation in the manufacture of garments made of polymeric materials is carried out. The analysis studied a wide range of possibilities for the use of nanotechnology in the garment industry and can serve as a theoretical basis for the manufacture of garments made of polymeric materials of various purposes, in particular for military and law enforcement agencies. The technology of rendering shape-resistant textiles, including clothing made of genuine leather, by use of the method of chemical modification and activation of its surface, which makes it possible to use more effectively various textile materials, in particular, leather at the cutting stage, is presented.

Microtensile dentin bond strength and interface morphology of different self-etching adhesives and universal adhesives applied in self-etching mode

To evaluate the microtensile dentin bond strength (BS) and dentin-adhesive morphology of three self-etching bonding systems and three universal adhesives applied in self-etching mode. Four single-step adhesives: G-Premio BOND (GPB), Bond Force II (BOF), Prime&Bond Active (PBA), and Adhese Universal (ADU); and two two-steps adhesives: Clearfil SE Bond (CSB) and Clearfil SE Bond 2 (CS2) were tested. Dentin surfaces of extracted third molars were prepared for microtensile bond strength test using adhesives applied according to the manufacturers’ instructions and restored with resin composite. Restored teeth (n = 8) were sectioned to obtain beam samples that were tested after 24 h and 1 year of water storage. Data were analyzed by two-way ANOVA repeated measures and Tukey's test (α = 0.05). The micromorphology of dentin-adhesive interfaces (n = 3) was analyzed by scanning electron microscopy (SEM) at 2.000× magnification. Self-etching adhesives exhibited different bond strength values at 24 h evaluation, which ranged from 20.7 to 77.9 MPa. PBA, ADU, CSB, and CS2 showed significantly higher dentin bond strength than GPB and BOF. These two single-step adhesives presented the lowest dentin bond strengths for both storage times, and interfacial study by SEM analysis revealed short and few resin tags formations. Water-storage for 1 year did not reduce the dentin bond strength of all adhesives tested. All self-etching and universal adhesives tested presented stable bond strength over one year of water storage. Both two-step self-etching adhesives yielded immediate and long-term higher dentin bond strength than most single-step adhesives tested.

Improving the Bond Strength of Radiographically Tagged Caries Lesions In Vitro.

After selective carious tissue removal, residual carious lesions remain radiographically detectable. Radiopaque tagging resolves the resulting diagnostic uncertainty but impedes bond strengths of adhesives to tagged dentin. We developed a protocol mitigating these detrimental effects. A 30%/50%/70% SnCl2 solution was dissolved in distilled water or a 30%/50%/90% ethanol solution (E30/60/90) and applied to artificially induced dentin lesions. Tagging effects were radiographically evaluated using transversal wavelength-independent microradiography (n = 6/group). Groups with sufficient tagging effects at the lowest SnCl2 concentrations were used to evaluate how tagging affected the microtensile bond strength of a universal adhesive (Scotchbond Universal) to sound and carious dentin (n = 10/group). Two different protocols for removing tagging material were tested: 15 s phosphoric acid etching and 5 s rotating brush application. Scanning/backscattered electron microscopy (SEM/BSE) and energy-dispersive X-ray spectroscopy (EDS) were used to assess surfaces after tagging and removal. The most promising removal protocol was revalidated microradiographically. Tagging significantly increased the radiopacity, with consistent effects for 30% SnCl2 dissolved in water or E30. Microscopically, tagged surfaces showed a thick carpet of SnCl2, and tagging reduced bond strengths significantly on carious dentin but not on sound dentin (p < 0.01). On carious dentin, removal of tagging material using acid etching and rotating brush was microscopically confirmed. Acid etching also mitigated any bond strength reduction (median: 21.3 MPa; interquartile range: 10.8 MPa) compared with nontagged dentin (median: 17.4 MPa; interquartile range: 20.6 MPa). This was not the case for brushing (median: 13.2 MPa; interquartile range: 13.9 MPa). Acid etching minimally reduced the radiographic tagging effect (p = 0.055). Phosphoric acid etching reduces the detrimental bond-strength effects of tagging without significantly decreasing radiographic tagging effects when using a universal adhesive.

The effect of additional chlorhexidine and/or ethanol on the bond strength of universal adhesives

The aim of this study was to evaluate the effect of chlorhexidine and/or ethanol application on the bond strength of two universal adhesive systems. 36 extracted human teeth were used in this study. Standard Class I cavities (4 × 3 × 3mm) were prepared and divided into two groups according to the adhesive systems used. Each group was subdivided into three subgroups to be treated with chlorhexidine, ethanol, or unexposed to any solution. Group I; Universal bond I was applied without any treatment. Group II; 2% chlorhexidine was applied, before the application of universal bond I. Group III; 100% ethanol was applied, before the application of universal bond I. Group IV; Universal bond II was applied without any treatment. Group V; 2% chlorhexidine was applied, before the application of universal bond II. Group VI; 100% ethanol was applied, before the application of universal bond II. Then, teeth were restored with a nano-hybrid resin composite then subjected to thermo-cycling (10,000 cycles, 5–55 °C). All teeth were exposed to 50,000 cycles of loading in a chewing simulator. Twelve sticks from each group were obtained using a cutting machine. Sticks were subjected to a microtensile bond strength. After procedures, fractured surfaces were observed under a stereomicroscope to determine the mode of failure. Hybrid layer of each group was evaluated under a scanning electron microscope (SEM). Data were submitted to the Kruskal Wallis test. Significance level was set at 5%.No statistically significant differences were shown in all groups (p > 0.05). The lowest bond strength value was obtained in group II (9.76), the highest bond strength value was determined in group IV (20.57). The study concluded that additional chlorhexidine or ethanol treatment may not influence directly the bond strength of universal adhesives when using a single-step self etch mode of universal adhesives.

Polyethylene wax as an alternative to mineral fillers for preparation of reinforced pressure-sensitive adhesives

Phase behavior, rheology and adhesive properties of polyisobutylene-based blends containing up to 60 wt% of polyethylene wax were studied. Polyisobutylene and wax partially dissolve in each other at high temperatures, which strongly reduce the viscosity of the blends and facilitate their mixing. When cooled, the wax loses its solubility in the polymer matrix and crystallizes to form reinforcing particles. These particles increase the viscoelasticity of the blends, resulting in improved durability (up to 66-fold) and strength (up to 1.4-fold) of adhesive bonds. At the same time, the growth of viscoelasticity does not lead to a loss of tackiness of the blends, as the application of external force to form an adhesive bond destroys the percolation structure of wax particles. Because of the low specific surface area of wax particles, they increase the durability of adhesive joints worse than silica (in 380-fold) or organoclay particles (in 3300-fold). However, the use of polyethylene wax allows reducing melt viscosity by 4–5 decimal orders of magnitude in the case of highly filled adhesives.

Durability and Mechanical Performance of Differently Treated Glulam Beams during Two Years of Outdoor Exposure

The performance of the composites is influenced by the service life of input raw wood material and used adhesives. The aim of the study was to assess the durability and mechanical performance of glulam beams treated in a different way (thermally modified and/or treated with copper-based wood preservative) and exposed in an outdoor application. Glulam beams (83 mm × 68 mm × 1100 mm), made of three layers of Norway spruce (Picea abies) with PUR adhesives used have been exposed in use class 3.2 in a horizontal position since 4th November 2016. Part of the specimens was equipped with MC sensors. Every year, the degradation was evaluated visually. The dynamic modulus of elasticity was determined by longitudinal vibration, and the static modulus of elasticity using a 4-point bending test. On the smaller specimens, cut from glulams, compressive strength, delamination, and shear strength of adhesive bonds were determined. After two years of exposure, the results indicate that the performance of glulams is determined by the wood modification and applied wood preservative.

Enhancing adhesive restoration effectiveness

Dental UpdateVol. 47, No. 7 CommentEnhancing adhesive restoration effectivenessTrevor BurkeTrevor BurkeSearch for more papers by this authorTrevor BurkePublished Online:30 Jul 2020https://doi.org/10.12968/denu.2020.47.7.545AboutSectionsView articleView Full TextPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InEmail View article References 1 Burke FJT, MacKenzie L, Sands P. Suggestions for non-aerosol or reduced-aerosol restorative dentistry (for as long as is necessary). Dent Update 2020; 47: 485–493. Link, Google Scholar2 Shaw K, Martins R, Hadis MA, Burke FJT, Palin WM. “Own label” versus branded commercial dental resin composite materials: mechanical and physical property comparison. Eur J Prosthodont Restor Dent 2016; 24: 122–129. Medline, Google Scholar3 Mickenautsch S. How well are GIC product labels related to current systematic review evidence? Dent Update 2011; 38: 634–644. Link, Google Scholar4 Johnsen GF, LeThieu MIC, Hussain B et al.. Own brand label restorative materials – a false bargain? J Dent 2017; 56: 84–98. Medline, Google Scholar5 Burke FJT, Crisp RJ. A practice-based assessment of patients' knowledge of dental materials. Br Dent J 2015; 219: 577–582. Medline, Google Scholar6 Burke FJT, Crisp RJ. A practice-based clinical evaluation of VOCO Ionolux. The Dentist 2017; Sept: 124–128. Google Scholar7 Stewardson DA, Creanor S, Thornley P, Biggs T. Burke FJT et al.. The survival of Class V restorations in general dental practice: part 3, five-year survival. Br Dent J 2012; 212: E14. Medline, Google Scholar8 Burke FJT, Mackenzie L, Shortall ACC. Survival rates of resin composite restorations in loadbearing situations in posterior teeth. Dent Update 2019; 46: 524–536. Link, Google Scholar9 Miletic I, Baraba A, Basso M et al.. Clinical performance of a glass-hybrid system compared with a resin composite in the posterior region: results of a 2-year multicenter study. J Adhes Dent 2020; 22: 235–247. Medline, Google Scholar10 Inoue S, Van Meerbeck B, Abe Y et al.. Effect of remaining dentine thickness and the use of conditioner on micro-tensile bond strength of a glass-ionomer adhesive. Dent Mater 2001; 17: 445–455. Medline, Google Scholar11 Sauro S, Watson TF, Thompson I et al.. Influence of air-abrasion executed with polyacrylic acid-Bioglass 45S5 on the bonding performance of a resin-modified glass ionomer cement. Eur J Oral Sci 2012; 120: 168–177. Medline, Google Scholar12 da Rosa WL de O, Piva E, da Silva AF. Bond strength of universal adhesives: a systematic review and meta-analysis. J Dent 2015; 43: 765–776. Medline, Google Scholar13 Zanatta RF, Silva TM, Esper Malr, BrescianiE, Goncalves Sep, Caneppele Tmf. Bonding performance of simplified adhesive systems in noncarious cervical lesions at 2-year follow-up: a double-blind randomized clinical trial. Oper Dent 2019; 44: 476–487. Medline, Google Scholar14 Cuevas-Suarez CE, da Rosa WL de O, Lund RG, da Silva AF, Piva E. Bonding performance of universal adhesives: an updated systematic review and meta-analysis. J Adhes Dent 2019; 21: 7–26. Medline, Google Scholar15 Dal-Bianco K, Pellizzaro A, Patzlaft R et al.. Effects of moisture degree and rubbing action on the immediate resin-dentin bond strength. Dent Mater 2006; 12: 1150–1156. Google Scholar16 Loguercio A, Munos MA, Lugue-Martinez I et al.. Does active application of universal adhesives to enamel in self-etch mode improve their performance? J Dent 2015; 43: 1060–1070. Medline, Google Scholar FiguresReferencesRelatedDetailsCited byTechnique tips: Ten top tips to overcome common mistakes concerning the use of dental materialsStephen J Bonsor25 September 2021 | Dental Update, Vol. 48, No. 8 2 July 2020Volume 47Issue 7ISSN (print): 0305-5000ISSN (online): 2515-589X Metrics History Published online 30 July 2020 Published in print 2 July 2020 Information© George Warman Publications (UK) LimitedPDF download

Hydrolysis-resistant and stress-buffering bifunctional polyurethane adhesive for durable dental composite restoration.

A new elastic polyurethane (PU) adhesive was reported in this study to improve the stability and durability of the dental adhesion interface. A polyurethane oligomer was synthesized by the solution polymerization method, and a diluent and solvent were added to prepare PU adhesives. The water sorption, water solubility, contact angle, thermal stability, degree of conversion and mechanical properties of the PU adhesives were evaluated. Experimental applications for tooth restoration (microtensile bond strength and microleakage) were also performed, and cytotoxicity test was carried out. The water sorption and solubility of the PU adhesives were significantly lower than those of three commercial adhesives. The microtensile bond strength of the PU adhesives was improved after thermocycling test, and the extent of microleakage was diminished when compared with that of commercial adhesives. Biocompatibility testing demonstrated that the PU adhesive was non-toxic to L929 fibroblasts. This study shows the ability of PU adhesive to improve the stability and durability of the dental adhesion interface and may refocus the attention of scientists from rigid bonding to flexible bonding for dental adhesion, and it sheds light on a new strategy for the stable and durable bonding interface of dentine adhesives.

Comparing the adhesion strength of 316L stainless steel joints after laser surface texturing by CO2 and fiber lasers

This paper focuses on the effects of the laser surface texturing process and joint configuration of stainless steel adherends on the adhesive tensile bond strength. Two different sources, a CO2 and a fiber laser, were used and compared. In particular, proper choice of laser parameters was explored with the aim of producing different roughness and peak-to-valley distance and different textures on the bonding area, which could increase the real contact surface. Furthermore, to more thoroughly understand the effect of the laser parameters on joint fracture load, the experimental campaign was conducted according to a Design of Experiment (DoE) framework and the results were analyzed with this methodology. The creation of particular textures and roughness levels were related to the resulting joint geometrical configuration and bond strengths. In particular, significant increases in joint bond strength were achieved using both laser sources. Furthermore, by optimizing the laser parameters, smaller laser spot scan path overlaps can be achieved as well as a more refined scale of surface texture and surface roughness. This thereby enables the joining of thinner sections of different materials.

Adhesive bond strength between orthodontic resin and acrylic surfaces

The use of orthodontic treatments in patients with temporary prostheses has been increasing, the purpose of this in vitro research is to measure the adhesive bond strength between orthodontic resin and acrylic surfaces by applying different procedures. Objective. To compare the adhesive bonding strength between orthodontic resin and acrylic surfaces under different application protocols. Methodology. Transversal, experimental, prospective study. In vitro with acrylic provisions, was carried out in the laboratory of the Faculty of Dentistry of the Universidad Veracruzana region of Veracruz. In the period of February-June of the year 2019. The sample was conformed by two control groups of specimens and four experimental ones, each group conformed by 20 specimens, in total 120 provisional ones were made in acrylic Nic Tone of quick self-cure. The tests performed by the ULTRATESTER machine were expressed in MPa. Later, the data obtained were processed in Excel tables (version) for statistical processing in SPSS version 24. Contribution. When comparing the pre-cutting protocol of acrylic surfaces with fine diamond bur and the protocol without pre-cutting, no statistically significant differences were found, therefore, this step could be omitted in clinical practice.