|Year : 2014 | Volume
| Issue : 1 | Page : 41-45
A comparison of the bond strength of different adhesive systems to dentin contaminated with chloroform
Neslihan Simsek1, Muhammet Yalçin2, Fuat Ahmetoglu1, Ali Keles1, Ayse Dundar3, Burak Dayi2
1 Department of Endodontics, Faculty of Dentistry, Inonu University, Malatya, Turkey
2 Department of Restorative Dentistry, Faculty of Dentistry, Inonu University, Malatya, Turkey
3 Department of Restorative Dentistry, Faculty of Dentistry, Abant İzzet Baysal University, Bolu, Turkey
|Date of Web Publication||20-Mar-2014|
Department of Endodontics, Faculty of Dentistry, Inonu University, Malatya - 44280
Source of Support: None, Conflict of Interest: None
Aim: The purpose of this study was to evaluate the microtensile bond strengths of five different bonding agents to dentin contaminated with chloroform which cleaning the remnants of the root canal sealer in coronal access cavities of teeth. Materials and Methods: A total of 30 extracted human mandibular molar teeth were used for study. Teeth were sectioned with diamond bur to expose the superficial dentin. AH Plus as a root canal sealer was placed to exposed dentin surface. Teeth were stored at least for 5 min motionless for sealer set. More of sealer on the surface of teeth was taken with the help of cotton pellets. Dentin surface was treated with 0.1 mL of chloroform which was kept for 1 min. After that, surfaces of teeth were flushed with distilled water and dried. Teeth were separated randomly into five groups and Clearfil SE Bond, Futura Bond M, Adper Easy Bond, Clearfil S3 Bond, and Optibond FL bonding agents were applied according to manufacturer's instructions. The specimens were sectioned parallel blocks approximately 1 mm thickness and 1 mm width. The specimens pasted apparatus and subjected to microtensile testing device with a crosshead speed of 1 mm/min. Connection surface of all samples was measured after the end of the test process. The connection types of surfaces were examined under a light microscope magnification Χ10. Results: There was no statistically significant difference between the Optibond FL and Adper Easy Bond. However, Adper Easy Bond gave higher binding than the other tested materials. There was no statistically difference among Optibond FL, Clearfil S3 Bond, and Clearfil SE Bond. Conclusions: Many endodontically treated teeth are lost due to poor restorative treatment of teeth. Endodontic treatment procedures will affect bonding agents, so it could result in failure of the restoration.
Keywords: Adhesive systems, chloroform, microtensile bond strengths
|How to cite this article:|
Simsek N, Yalçin M, Ahmetoglu F, Keles A, Dundar A, Dayi B. A comparison of the bond strength of different adhesive systems to dentin contaminated with chloroform. J Res Dent 2014;2:41-5
|How to cite this URL:|
Simsek N, Yalçin M, Ahmetoglu F, Keles A, Dundar A, Dayi B. A comparison of the bond strength of different adhesive systems to dentin contaminated with chloroform. J Res Dent [serial online] 2014 [cited 2019 Dec 13];2:41-5. Available from: http://www.jresdent.org/text.asp?2014/2/1/41/129024
| Introduction|| |
Root canal sealer which infected to pulp chamber after a successful endodontic treatment must be cleaned. At the same time, root canal filling material and the root canal filling which composed of root canal sealer must be removed from the root canal to renew the therapy in failed endodontic treatments.
Thermal, mechanical, and chemical methods can be used alone or together with all to remove the root canal filling materials.  Nowadays, different solvents have been investigated to remove gutta percha and root canal sealers when the retreatment application is necessary especially in problematic canals. The most commonly used organic solvents in endodontics are chloroform, xylol, halothane, eucalyptol, turpentine, and citrus oil. Previous studies revealed that chloroform is a good solvent which uses to remove softened endodontic sealers and gutta percha and has the high volatility. ,,
Light-cured composites have been used increasing frequency in amalgam restorations as an alternative restorative material thanks to their esthetic features and easy to use.  Over the past decade, the use of resin-based dental composite fillings has increased significantly with the development of adhesive and composite resin systems.  The bonding of composite resins to dental tissues as micromechanic is provided in three different techniques (single, two, or three-stage adhesive systems).  As a result of insufficient adhesion of composite resin to dentin results decreased linkage, microleakage, and recurrent caries. If the residues can be removed from the dentin surface, it provides a minerally rich suitable surface for bonding procedures in the bottom. 
The bonding strength tests like microtensile test are used to measure the bonding of the systems to dental tissues in accordance with the importance of clinical achievement of bonding strength of adhesive systems used in dentistry to dentin.  Small bonding surfaces used in the microtensile test provides fewer defects when compared with large surfaces, in this case results higher bonding strength than other testing methods that are used for large surface areas. Therefore, the microtensile technique can be used to determine of the regional differences of resin-dentin bonding strengths due to the use in small bonding areas. ,
The aim of this study is to compare microtensile test and the bonding strengths of the teeth which were completed root canal treatment by applying five different bond system [Table 1] [three single-step self-etch, one two-step self-etch, and one three-step total etch] after cleaning of the remaining root canal sealer residues in coronal room with the help of a solvent material.
| Material and Methods|| |
Preparation of teeth
After approval by the Ethics Committee (2012/145) in this study, 30 mandibular molar teeth used which extracted for periodontal reasons. Soft tissues were removed with the help of periodontal curette (H6/H7 Scaler, Hu-Friedy, Chicago, IL, USA). After cleaning the teeth, each tooth buried into autopolymerized acrylic resin in plastic cylindrical containers which has 20 mm high and 20 mm wide (Palapress Vario, Heraeus Kulzer GmbH, Wehrheim, Germany). Then, the superficial dentin in occlusal parts of teeth revealed until, occlusal surface of teeth was abraded with the aid of the diamond saw under water cooling at low speed (Isomet, Buehler, Ltd., Lake Bluff, IL, USA).Then the occlusal surfaces were standardized by sanding process with a 600-grit silicon carbide paper until obtaining a surface which parallel to the floor.
Application of materials
Prepared AH Plus root canal sealer in accordance with the manufacturer's instructions was placed into the exposed dentin surface. For at least 5 min the teeth was allowed to settle the root canal sealer without dislocate. A total of 0.1 mL of chloroform dropwise and 1 min kept on the root canal sealer which much of it was taken with the help of cotton pellet from tooth surface. Then the tooth surfaces were washed with distilled water and dried. One-step self-etch Futura Bond M (Voco, Cuxhaven, Germany), Adper Easy Bond (3M ESPE, St. Paul, MN, USA), Clearfil S3 Bond (Kuraray Medical Inc., Tokyo, Japan), a two-stage self-etch Clearfil SE Bond (Kuraray Co., Ltd., Osaka, Japan), and a three-step total etch Optibond FL (Kerr, Danbury, CT, USA) was performed in accordance with the manufacturer's instructions to the teeth which randomly allocated into five groups. AutoMatrix system (DentsPly, DeTrey GmbH, Konstanz, Germany) placed on the teeth and occlusal surfaces of the teeth is covered with the 2 mm thick Spectrum TPH3 composite (DentsPly, DeTrey GmbH, Konstanz, Germany) and the polymerization was provided by applying light-emitting diode light for 20 s (Woodpecker, Guilin, Guangxi, China).
Sample preparation and micro-tensile test
Then, 6 mm in length parallel blocks (1 mm 2 sections) was obtained from the teeth under water cooling with Isomet 1000 diamond saw at low speed. The 6 mm 3 dimensioned 40 blocks were obtained from teeth for each material. Obtained parallel blocks were attached to microtensile test apparatus (Bisco, Schamburg, Illinois, USA) with cyanoacrylate glue (Pattex, Henkel KGaA, Düsseldorf, Germany) and the pulling force was applied to the examples for 1 mm/min in microtensile test device. After finished the test, the bonding surface of all samples were measured tested and the bond strength values were calculated as MPa. The fracture types of the bonding surfaces were determined by examining with a light microscope (Olympus SZ4045 TRPT, Japan) ×10 magnifications.
One-way analysis of variance method was used to assess the significance of statistically of the tensile bonding force. Also Tukey's post-hoc multiple comparison was used to evaluate the significance of statistically of the bonding strength deviations of subgroups after different applications. Degree of statistical significance is P = 0.05. A total of 40 samples were tested from each group. Statistical analysis was carried out with SPSS (SPSS 14.0, Windows).
| Results|| |
While it was found no statistically significant differences between Adper Easy Bond and Optibond FL in terms of the bond strength, Adper Easy Bond showed quantitatively higher bonding compared to other tested materials. Clearfil SE Bond, Clearfil S3 Bond, and Optibond FL were statistically the same group. Futura Bond M showed minimum bonding quantitatively [Table 2].
|Table 2: Measured data obtained from micro tensile testing device (mean±SD)|
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| Discussion|| |
In this study, the bonding strengths of single step self-etch, two-step self-etch, and three-step total etch bond systems that applied to surface of the samples (contaminated with root canal sealer) after cleaning with chloroform were compared with microtensile testing method.
Lee et al., showed that epoxy resin root canal sealers adhered to dentine and gutta percha more than other types cements. In our study AH Plus, which is an epoxy resin root canal sealer that it has been accepted the availability of it, was used.
Heat or solvents are also used in removing of filling materials from root canals as well as hand and rotary tools.  Use of the solvents reduces the removal time of cement and amount of the residue.  Azar et al.,  used chloroform as a solvent which is more effective than other organic solvents that solve root canal filling materials in their study. In this study, chloroform was also used as the solvent to remove root canal sealer.
Sano et al.,  used the samples which have about 1 mm 2 bonding surface to test the microtensile bond strength and as a result, they obtained the higher bond strength values in comparison with the studies that carried out with the samples which have larger bonding surface. Therefore, the sections which are 1 mm 2 size were used in this study.
Roberts et al.,  used the samples which were contaminated the dentin surface with AH Plus root canal sealer and cotton pellets, ethanol, and Endosolv R/water were used to clean the dentin surface by forming separate groups in their study. Then, the tensile bonding strengths were examined, using the two different bond systems. According to the results of this study, the highest tensile bonding value was shown in uncontaminated surface samples (control group), while the lowest tensile bonding value was determined in the surface samples that were cleaned with cotton pellets. This confirms that dentin contamination affects adhesive bonding strength.
Self-etch systems do not require pickling and washing phase in a separate step. In the content, the acidic monomers are available which demineralize enamel and dentin simultaneously and provide primer infiltration. Thus, they reduce the possibility of making a mistake by making easier the transaction process as well as reduce the clinical practice time.  Self-etch adhesive systems bond to dentine with the hybrid layer which originates with infiltration of the adhesive to collagen fibrils that arose with change of the smear layer.  Pashley and Carvalho  reported that the adhesives infiltrated completely to the interfibrillar space in dentin surface due to the comonomers in the content of self-etch adhesives. Resin infiltration is one of the factors that affects the bonding strength values. The results of this study are thought to provide that Adper Easy Bond which is one-step self-etch system uses with removing root canal sealer residues thanks to infiltration of chloroform into collagen fibrils.
Sensi et al.,  reported that the bonding strength of one-step self-etch adhesives to dentine is lower than total etch adhesive system and two-step self-etch adhesive system. On the contrary, in our study, the bonding strength values of Adper Easy Bond which is one-step self-etch adhesive system showed no statistically significant difference with Optibond FL, while it showed the higher bonding strength value compared to Clearfil SE which is a two-step self-etch adhesive system.
An in vitro study that compared to three different 7 th generation one-step self-etch adhesive system Adper Easy One Bond system showed significantly higher tensile bonding strength than two other adhesive systems.  In this study, Adper Easy Bond also showed higher bonding value than other adhesive systems.
Consequently in this study after removing contaminated dentin surface with root canal sealer with the help of the solvent, Adper Easy Bond (a one-step self-etch adhesive system) and Optibond FL (a three-step total etch system) showed the highest bonding strength values. This shows that self-etch adhesive systems exhibit the bonding strength as good as total etch adhesive systems. Also, it has been revealed that the root canal sealers which contaminate pulp chamber during endodontic treatment affect the bonding strength of adhesive systems by blocking the infiltration of resin in the adhesive system into collagen fibrils, for this reason after root canal treatment the root canal sealer residues must be removed with solvents before using adhesive system for the coronal restoration of the tooth. Accordingly the restoration period and residence time in the mouth of tooth may be extended by increasing effectiveness of bond systems that use for coronal restoration of tooth with the adhesive systems after root canal treatment.
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[Table 1], [Table 2]