|Year : 2017 | Volume
| Issue : 2 | Page : 71-75
Microshear bond strength of Nano-Bond adhesive containing nanosized aluminum trioxide particles
Yousef Mohammed Althomali1, Mohamed Ismail Ebrahim2
1 Department of Preventive Dentistry, Faculty of Dentistry, Taif University, Taif, Saudi Arabia
2 Department of Dental Biomaterial, Faculty of Dental Medicine, Al-Azhar University, Cairo, Egypt; Department of Dental Biomaterial, Taif University, Taif, Saudi Arabia
|Date of Web Publication||2-May-2017|
Yousef Mohammed Althomali
Faculty of Dentistry, Taif University, Taif
Source of Support: None, Conflict of Interest: None
Objectives: The present study was conducted to evaluate the effect of nanosized aluminum trioxide (Al2O3) particles when added to the Nano-Bond adhesive system and its effect on the microshear bond strength of nanocomposite resin to dentin.
Materials And Methods: A newly developed adhesive (Nano-Bond) and one type of light-cured resin restorative material (nanocomposite resin) were used in this study. The occlusal surfaces of extracted human molar teeth were ground perpendicular to the long axis of each tooth to expose a flat dentin surface. The adhesives were applied to the dentin surfaces according to manufacturers' instructions. The nanocomposite resin was then placed and light cured for 40 s. After immersion in water at 37°C for 24 h, the specimens were subjected to thermocycling before testing, and a microshear bond test was carried out. The recorded bond strengths (MPa) were collected, tabulated, and statistically analyzed. A one-way analysis of variance and Tukey's tests were used to test for significance between the means of the groups; statistical significance was assumed when the P ≤ 0.05.
Results: The mean microshear bond strength of the Nano-Bond adhesive system containing nanosized Al2O3at a concentration of 2% was 23.15 MPa (Group B), which was significantly greater than that of the Nano-Bond adhesive system without additives (15.03 MPa, Group A).
Conclusions: These results indicate that nanosized Al2O3added to the Nano-Bond adhesive system at a concentration of 2% increases the microshear bond strength.
Keywords: Aluminum trioxide particles, Nano-Bond adhesive, shear bond strength
|How to cite this article:|
Althomali YM, Ebrahim MI. Microshear bond strength of Nano-Bond adhesive containing nanosized aluminum trioxide particles. J Orthodont Sci 2017;6:71-5
|How to cite this URL:|
Althomali YM, Ebrahim MI. Microshear bond strength of Nano-Bond adhesive containing nanosized aluminum trioxide particles. J Orthodont Sci [serial online] 2017 [cited 2018 May 23];6:71-5. Available from: http://www.jorthodsci.org/text.asp?2017/6/2/71/205452
| Introduction|| |
Nearly half of all dental restorations fail within 10 years, and replacement of these failed restorations accounts for 50%–70% of all procedures in restorative dentistry. Composites are popular filling materials because of their esthetics and direct-filling capabilities.,,,,, One main problem, however, is that composite tends to accumulate more biofilms than other restorative materials in vivo., Biofilms at the restoration margins could produce acids and cause secondary caries, the main reason for restoration failure.,
From restorative dentistry, the use of bonding agents is known to improve the adhesion of composite resins. Bonding agents create a micromechanical interlock between the dentin collagen and resin by forming hybrid layers.
Bonding agents adhere the composite restoration to the tooth structure to form a functional and durable interface.,, Bonding agent compositions and bond strengths have been improved in previous studies., Antibacterial adhesives are promising for combating bacterial infection and reducing recurrent caries at tooth-restoration margins.,
Nanosized fillers, such as nanosized aerosol silica filler, were introduced to the field of bonding agents by means of nanotechnology. Nanofiller technology is claimed to increase adhesion to both the enamel and dentin and improves marginal integrity.
Recently, quaternary ammonium dimethacrylate was synthesized and incorporated into resins to inhibit biofilm growth.,
Traditionally, micro/nanofillers have been introduced into epoxy resins to improve their mechanical performance, for example, silicon, titanium, and aluminum oxides. The use of nanosized aluminum trioxide (Al2O3) particles is one approach to improve the mechanical performance of adhesive materials. In these particulate-filled systems, binding at the inorganic filler/epoxy matrix interface has a great effect on the mechanical properties of the adhesive material. Dudkin et al. demonstrated that the strength of the epoxy matrix was increased when reinforced by Al2O3 because of interactions between the active surface groups of the oxide nanoparticles and the functional groups of the epoxy matrix.
However, whether the addition of filler particles improves the mechanical behavior of these adhesives still remains unclear since their mechanical properties rely on other factors that cannot be studied in isolation using commercial adhesive systems.
The purpose of this study was to evaluate the effect of adding nanosized Al2O3 particles at a concentration of 2% to Nano-Bond adhesive on the microshear bond strength of nanocomposite resin to dentin.
| Materials and Methods|| |
One available type of adhesive system was used as the control (Nano-Bond adhesive; Pentron Clinical Technologies, USA; lot #183421). Nanosized Al2O3 particles at a 2% concentration were added to Nano-Bond adhesive; this and one type of nanofilled composite resin (Artiste Nanocomposite, Pentron Clinical Technologies; lot #182066-185215) were used in this study.
Twenty caries-free freshly extracted human molar teeth were collected to be used in this study. The teeth were cleaned by an ultrasonic scaler and stored in distilled water at 37°C before testing. A dentin slice approximately 1.0-mm thick was cut perpendicular to the long axis of each tooth from the upper middle coronal portion region using a low-speed diamond saw (Isomet, Buehler, Lake Bluff, IL, USA) under water coolant. The occlusal surfaces of the slices were ground with up to 600-grit silicon carbide paper to expose a flat dentin surface.,,,
A dentin slices were divided into two main groups (ten each) according to the bonding agent containing nanosized Al2O3 particles at a 2% concentration. Group A was tested using the Nano-Bond adhesive system without additives, and Group B was tested using the Nano-Bond adhesive system containing nanosized Al2O3 particles at a 2% concentration.
Each dentin slice was acid etched using 37% phosphoric acid gel (Eco-Etch; Ivoclar Vivadent, Schaan, Liechtenstein, Swiss) for 15 s. Then, the dentin slices were rinsed with water spray and dried in an oil-free stream of air for 5 s. The adhesives were applied according to manufacturers' instructions. The adhesives were applied to the entire dentin surface and air-dried for 15 s. A gentle stream of dry air was applied to disperse the material into a thin, uniform, shiny surface, and before irradiation, three or four cylinders (internal diameter: 0.7 mm, height: 1.0 mm) of microbore Tygon tubing (R-3603, Norton Performance Plastic Co., Cleveland, OH, USA) were placed on the flat dentin at different locations. The adhesive was then light cured for 10 s with light-emitting diodes (BG Light Ltd., 4002 Plovdiv, Bulgaria; 430–490 nm).
After irradiation, the tubing was filled with nanofilled composite resin and then light cured for 40 s with the tip as close to the surface as possible. Curing radiometer equipment (LI-189 Li-Cor Inc., Lincoln, NE, USA) was used to ensure steady light intensity throughout the polymerization of all specimens. The specimens were stored under moist conditions at room temperature (23°C) for 1 h before removing the Tygon tubing.
The specimens were immersed in water at 37°C for 24 h, then subjected to thermocycling to simulate clinical thermal stress conditions before testing according to the guidelines set by the American National Standards Institute/American Dental Association  and International Organization for Standardization  for direct filling resins and dental adhesion.
All specimens were subjected to thermocycling by storing them alternately in water reservoirs at 5°C and 55°C, with the specimen staying in each reservoir for 30 s. This procedure was carried out for 500 cycles and controlled by a computer to simulate thermal stress.
The resin cylinders were then subjected to the microshear bond test. A diagram of the microshear bond test setup is shown in [Figure 1]. Each dentin slice with the resin cylinders was placed in the lower attachment of a Lloyd universal testing machine (model LRX plus II, Fareham, England) for microshear bond testing.
A thin wire (diameter, 0.20 mm) was looped around each resin cylinder, making contact with half of the cylinder base, and was placed as close as possible to the resin-dentin interface. A shear force was applied to each specimen at a crosshead speed of 0.5 mm/min until failure occurred. The resin-dentin interfaces of the specimens and the wire loops were aligned as straight as possible to ensure that the same shear orientation was maintained. The loads at failure were recorded, and the data were analyzed by one-way analysis of variance and Tukey's tests were used to test the significance of differences between the means of the tested materials, which were considered statistically significant when the P ≤ 0.05.
| Results|| |
The mean percentages for the tested Nano-Bond adhesive system without additives and Nano-Bond adhesive system containing nanosized Al2O3 particles at a 2% concentration are presented in [Table 1] and [Figure 2].
|Table 1: Comparison between mean microshear bond strength in (MPa) of the tested Nano-Bond adhesive system groups|
Click here to view
|Figure 2: A bar chart of the mean microshear bond strengths (MPa) of the tested Nano-Bond adhesive system groups|
Click here to view
The Nano-Bond adhesive system containing nanosized Al2O3 particles at a 2% concentration (Group B) showed a statistically significantly greater mean microshear bond strength (23.15 MPa) than that of the Nano-Bond adhesive system without additives (15.03 MPa, Group A).
The results of the microshear bond strength test showed a significant difference (P < 0.05) between Group B and Group A. The microshear bond strength was increased in the specimens containing nanoparticles of Al2O3.
| Discussion|| |
The major goals of using dentin bonding systems are to enhance the bonding strength between the resin and the tooth structure, increase the retention of the restoration, reduce microleakage across the dentin-resin interface, and dissipate occlusal stress.
The adhesive layer acts as an elastic intermediate layer (elastic cavity wall) between the cavity walls and the adjacent composite. This layer could resist polymerization shrinkage stress from resin composites and absorbs shocks produced by occlusal loads and thermal cycling.
According to many investigators, the use of filled adhesive resin increases its mechanical properties and improves the marginal and internal seals of composite restorations.
These adhesives may be categorized as mild or strong adhesives depending on their pH and therefore their etching potential. If the adhesive's capacity dissolves the smear layer is limited, the bond strength to dentin with a thick smear layer may be reduced.
The shear bond strength test has been widely used, mainly because of its relative simplicity when compared with the tensile bond strength test, in which it is difficult to align the specimen in the testing machine without creating a deleterious stress distribution., Advantages of shear tests include the specimen preparation and simple test protocols.
A new test method using specimens with reduced dimensions has been advocated by some authors ,, as a substitute for the conventional shear test: this called microbond or microshear bond strength test. According to these authors, this test would allow for the testing of small areas of material, thus permitting a regional mapping or depth profiling of different substrates and preparing multiple specimens from the same tooth.
The present study used nanosized Al2O3 particles at a 2% concentration in the adhesive because the antimicrobial activity of aluminum nanoparticles is due to the release of metal ions and because aluminum ion nanoparticles attach to the surface of bacteria because of their surface charge; the charge of the bacterial surface is negative while that of the aluminum nanoparticles is positive at the pH studied.
The present study showed that the microshear bond strength of Nano-Bond adhesive containing nanosized Al2O3 particles at a 2% concentration was greater than that of the Nano-Bond adhesive system without additives. Factors contributing to this effect may include the fact that the number of metal–oxygen (Me-O) bonds increases with the release of residual water and organic solvent during the early stages of drying. Therefore, a further increase in cross-linking and Me-O bonding occurred during the curing regimen because the release of water and solvent from the adhesive is controlled by the cure time  and thus increased the bond strength to dentin.
| Conclusions|| |
The addition of nanosized Al2O3 particles at a concentration of 2% to Nano-Bond adhesive increased the microshear bond strength.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| References|| |
Frost PM. An audit on the placement and replacement of restorations in a general dental practice. Prim Dent Care 2002;9:31-6.
Lim BS, Ferracane JL, Sakaguchi RL, Condon JR. Reduction of polymerization contraction stress for dental composites by two-step light-activation. Dent Mater 2002;18:436-44.
Watts DC, Marouf AS, Al-Hindi AM. Photo-polymerization shrinkage-stress kinetics in resin-composites: Methods development. Dent Mater 2003;19:1-11.
Xu X, Ling L, Wang R, Burgess JO. Formulation and characterization of a novel fluoride-releasing dental composite. Dent Mater 2006;22:1014-23.
Drummond JL. Degradation, fatigue, and failure of resin dental composite materials. J Dent Res 2008;87:710-9.
Samuel SP, Li S, Mukherjee I, Guo Y, Patel AC, Baran G, et al.
Mechanical properties of experimental dental composites containing a combination of mesoporous and nonporous spherical silica as fillers. Dent Mater 2009;25:296-301.
Ferracane JL. Resin composite – State of the art. Dent Mater 2011;27:29-38.
Imazato S, Torii M, Tsuchitani Y, McCabe JF, Russell RR. Incorporation of bacterial inhibitor into resin composite. J Dent Res 1994;73:1437-43.
Beyth N, Domb AJ, Weiss EI. An in vitro
quantitative antibacterial analysis of amalgam and composite resins. J Dent 2007;35:201-6.
Jokstad A, Bayne S, Blunck U, Tyas M, Wilson N. Quality of dental restorations. FDI Commission Project 2-95. Int Dent J 2001;51:117-58.
Sakaguchi RL. Review of the current status and challenges for dental posterior restorative composites: Clinical, chemistry, and physical behavior considerations. Summary of discussion from the Portland Composites Symposium (POCOS) June 17-19, 2004, Oregon Health and Science University, Portland, Oregon. Dent Mater 2005;21:3-6.
Gogos C, Stavrianos C, Kolokouris I, Papadoyannis I, Economides N. Shear bond strength of AH-26 root canal sealer to dentine using three dentine bonding agents. J Dent 2003;31:321-6.
Ikemura K, Tay FR, Endo T, Pashley DH. A review of chemical-approach and ultramorphological studies on the development of fluoride-releasing dental adhesives comprising new pre-reacted glass ionomer (PRG) fillers. Dent Mater J 2008;27:315-39.
Park JG, Ye Q, Topp EM, Misra A, Spencer P. Water sorption and dynamic mechanical properties of dentin adhesives with a urethane-based multifunctional methacrylate monomer. Dent Mater 2009;25:1569-75.
Garcia-Godoy F, Krämer N, Feilzer AJ, Frankenberger R. Long-term degradation of enamel and dentin bonds: 6-year results in vitro
vs. in vivo
. Dent Mater 2010;26:1113-8.
Shinohara MS, De Goes MF, Schneider LF, Ferracane JL, Pereira PN, Di Hipólito V, et al.
Fluoride-containing adhesive: Durability on dentin bonding. Dent Mater 2009;25:1383-91.
Swift EJ. Critical appraisal. Options for dentin/enamel bonding: Part IV. J Esthet Restor Dent 2010;22:270-5.
Imazato S, Kinomoto Y, Tarumi H, Ebisu S, Tay FR. Antibacterial activity and bonding characteristics of an adhesive resin containing antibacterial monomer MDPB. Dent Mater 2003;19:313-9.
Imazato S, Tay FR, Kaneshiro AV, Takahashi Y, Ebisu S. An in vivo
evaluation of bonding ability of comprehensive antibacterial adhesive system incorporating MDPB. Dent Mater 2007;23:170-6.
Wegdan M. Effect of cutting bur on the bond strength of a self-etching and one bottle nanofilled adhesives to enamel and dentin. Egypt Dent J 2005;51:1171-9.
Antonucci JM, Zeiger DN, Tang K, Lin-Gibson S, Fowler BO, Lin NJ. Synthesis and characterization of dimethacrylates containing quaternary ammonium functionalities for dental applications. Dent Mater 2012;28:219-28.
Cheng L, Weir MD, Xu HH, Antonucci JM, Kraigsley AM, Lin NJ, et al.
Antibacterial amorphous calcium phosphate nanocomposites with a quaternary ammonium dimethacrylate and silver nanoparticles. Dent Mater 2012;28:561-72.
Dudkin B, Zainullin G, Krivoshapkin P, Krivoshapkina E, Ryazanov M. Influence of nanoparticles and nanofiberes of aluminium oxide on the properties of epoxy composites. Glass Phys Chem 2008;34:187-91.
Conde MC, Zanchi CH, Rodrigues-Junior SA, Carreño NL, Ogliari FA, Piva E. Nanofiller loading level: Influence on selected properties of an adhesive resin. J Dent 2009;37:331-5.
Kim JS, Cho BH, Lee IB, Um CM, Lim BS, Oh MH, et al.
Effect of the hydrophilic nanofiller loading on the mechanical properties and the microtensile bond strength of an ethanol-based one-bottle dentin adhesive. J Biomed Mater Res B Appl Biomater 2005;72:284-91.
McDonough WG, Antonucci JM, He J, Shimada Y, Chiang MY, Schumacher GE, et al.
A microshear test to measure bond strengths of dentin-polymer interfaces. Biomaterials 2002;23:3603-8.
McDonough WG, Antonucci JM, Dunkers JP. Interfacial shear strengths of dental resin-glass fibers by the microbond test. Dent Mater 2001;17:492-8.
Shimada Y, Iwamoto N, Kawashima M, Burrow MF, Tagami J. Shear bond strength of current adhesive systems to enamel, dentin and dentin-enamel junction region. Oper Dent 2003;28:585-90.
Shimada Y, Kikushima D, Tagami J. Micro-shear bond strength of resin-bonding systems to cervical enamel. Am J Dent 2002;15:373-7.
American Dental Association Council on Scientific Affairs: American National Slandered/American Dental Association (ANSI/ADA) No. 27: Dentistry-Polymer-Based Filling Restoration and Lating Material; 2002. p. 263-7.
International Organization for Standardization (ISO). Mechanical Specification 11405; Dental Materials, Testing of Adhesion to Tooth Structure; 2001.
Janda R, Roulet S, Latta M, Ruttermann S. The effects of thermocycling on the flexural strength flexural modulus of modern resin-based filling materials. J Dent Res 2006;22:812-7.
Chen RS, Liu CC, Tseng WY, Jeng JH, Lin CP. Cytotoxicity of three dentin bonding agents on human dental pulp cells. J Dent 2003;31:223-9.
Kemp-Scholte CM, Davidson CL. Marginal integrity related to bond strength and strain capacity of composite resin restorative systems. J Prosthet Dent 1990;64:658-64.
Labella R, Lambrechts P, Van Meerbeek B, Vanherle G. Polymerization shrinkage and elasticity of flowable composites and filled adhesives. Dent Mater 1999;15:128-37.
Choi KK, Condon JR, Ferracane JL. The effects of adhesive thickness on polymerization contraction stress of composite. J Dent Res 2000;79:812-7.
Oilo G. Bond strength testing – What does it mean? Int Dent J 1993;43:492-8.
Sudsangiam S, van Noort R. Do dentin bond strength tests serve a useful purpose? J Adhes Dent 1999;1:57-67.
Kemp-Scholte CM, Davidson CL. Marginal sealing of curing contraction gaps in Class V composite resin restorations. J Dent Res 1988;67:841-5.
Liberman R, Ben-Amar A, Herteanu L, Judes H. Marginal seal of composite inlays using different polymerization techniques. J Oral Rehabil 1997;24:26-9.
Lutz F, Krejci I, Luescher B, Oldenburg TR. Improved proximal margin adaptation of Class II composite resin restorations by use of light-reflecting wedges. Quintessence Int 1986;17:659-64.
Braem M, Lambrechts P, Vanherle G, Davidson CL. Stiffness increase during the setting of dental composite resins. J Dent Res 1987;66:1713-6.
Jiang W, Mashayekhi H, Xing B. Bacterial toxicity comparison between nano- and micro-scaled oxide particles. Environ Pollut 2009;157:1619-25.
Habsuda J, Simon G, Cheng Y, Hewitt D, Lewis D, Toh H. Organic-inorganic hybrids derived from 2-hydroxyethylmethacrylate and (3-methacryloyloxypropyl)-trimethoxysilane. Polymer 2002;43:4123-36.
May M. The Use of Sol-Gel Technology for Adhesive and Structural Durability Applications. PhD Thesis, Sheffield Hallam University; 2010.
[Figure 1], [Figure 2]