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Table of Contents   
ORIGINAL ARTICLE  
Year : 2020  |  Volume : 23  |  Issue : 2  |  Page : 169-173
Comparative evaluation of shear bond strength of sixth- and seventh-generation bonding agents with varying pH – An in vitro study


Department of Conservative Dentistry and Endodontics, Maratha Mandal Nathagirao G Halgekar Institute of Dental Sciences and Research Centre, Belgaum, Karnataka, India

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Date of Submission23-Dec-2019
Date of Decision27-Jun-2020
Date of Acceptance27-Jul-2020
Date of Web Publication05-Nov-2020
 

   Abstract 

Introduction: To compare and evaluate the shear bond strength of sixth- and seventh-generation bonding agents with varying pH – an in vitro study.
Materials and Methods: Eighty extracted human premolar teeth were collected and cleaned and polished with pumice and water. The root portion of teeth was resected, and only the coronal portion was embedded in the cold-cure acrylic resin. The labial surface of mounted teeth was prepared with a high-speed handpiece using #245 carbide bur. The samples prepared were divided into four groups, with 20 specimens in each group:

  • Group A: Sixth-generation bonding agent, Adper Prompt L-Pop (APLP) (3M ESPE)
  • Group B: Sixth-generation bonding agent, Xeno III (X III) (Dentsply)
  • Group C: Seventh-generation bonding agent, Adper Easy One (AEO) (3M ESPE)
  • Group D: Seventh-generation bonding agent, Xeno IV (X IV) (Dentsply).

Tooth surface were rinsed and dried, and bonding agents were applied on tooth surface. Composite resin (Z-350 XT, 3M ESPE) was placed in a two-layer increment on tooth and was light cured. Specimens were subjected to the universal testing machine in a compression mode force at a crosshead speed of 1 mm/min keeping blade parallel to the adhesive–dentin interface. Shear force required to debond the specimen was recorded in megapascal. The data obtained were analyzed statistically using ANOVA and post hoc test.
Results: AEO (pH = 2.3, Group C seventh generation) showed higher bond strength, and pH values did not influence the shear bond strength significantly in the tested adhesive systems.
Conclusion: The pH values did not influence the shear bond strength significantly in the tested adhesive systems. ADPER EASY ONE (pH= 2.3, GROUP C Seventh Generation) showed higher bond strength followed by XENO IV(pH = 2.1, GROUP D) ,XENO III (pH = 1.5, GROUP B) on dentinal surface ,where as ADPER PROMPT L POP (pH =0.7 to 1 Sixth Generation, GROUP A) showed lower bond strength.

Keywords: Newer bonding agent; pH; shear bond strength

How to cite this article:
Jamadar A, Vanti A, Uppin V, Pujar M, Ghivari S, Vagarali H. Comparative evaluation of shear bond strength of sixth- and seventh-generation bonding agents with varying pH – An in vitro study. J Conserv Dent 2020;23:169-73

How to cite this URL:
Jamadar A, Vanti A, Uppin V, Pujar M, Ghivari S, Vagarali H. Comparative evaluation of shear bond strength of sixth- and seventh-generation bonding agents with varying pH – An in vitro study. J Conserv Dent [serial online] 2020 [cited 2020 Dec 3];23:169-73. Available from: https://www.jcd.org.in/text.asp?2020/23/2/169/300024

   Introduction Top


Adhesive techniques for restoration of teeth have broadened the horizons of esthetic dentistry. In the initial era of restorative dentistry, retention of restoration often needed the removal of sound tooth structure to provide large undercuts and to gain auxiliary retentive aids.[1] The introduction of newer bonding systems in adhesive dentistry resolves this problem. Adhesive restoration reinforces the weakened tooth structure by effectively conducting the functional stresses across the bonding interface.[2],[3]

Self etch adhesives simplified the bonding procedures, were developed and to prevent discrepancies between the depth of dentin demineralize by the acid and the ability of primer to penetrate this demineralize layer.[3],[4]

The self-etch adhesives use weaker acids that remove the smear layer partially and maintain the smear plugs and create thin hybrid layers.

These simplified systems are suggested to reduce technique sensitivity and shorten clinical procedures.[3],[4]

The self-etch adhesive pH is higher than phosphoric acid. Self-etch adhesives are classified into three categories based on pH value: mild (pH of 2.5 or more) moderate (pH of approximately 1), and strong (pH <1) dissolve the smear layer completely and form a relatively thick transitional layer. Currently, several self-etching systems are available, but insufficient information is known about their capacity to adhere to dental hard tissues.

Since testing bond strength is used as a screening tool to help understand and predict the clinical behavior of adhesives, this in vitro study was designed to investigate and compare the shear bond strength to dentin using several self-etch adhesive systems with varying pH.


   Materials and Methods Top


Eighty extracted intact human premolar teeth were collected and cleaned, and then, the teeth were polished with slurry of pumice and water. The root portion of teeth was resected, and only the coronal portion was embedded in the cold-cure acrylic resin with the help of custom-made silicone rubber mold of dimensions 2 cm × 2 cm.

Teeth were then mounted horizontally, and labial surface was prepared with high-speed handpiece using #245 carbide bur.

The samples prepared were then divided into four groups with 20 specimens in each group, and for ease of identification purpose, each acrylic block was painted with different colors.

  • Group A: Sixth-generation bonding agent, Adper Prompt L-Pop (APLP) (3M ESPE) Red
  • Group B: Sixth-generation bonding agent, X III (Dentsply) Green
  • Group C: Seventh-generation bonding agent, Adper Easy One (AEO) (3M ESPE) Yellow
  • Group D: Seventh-generation bonding agent, X IV (Dentsply) Pink.


Tooth surface was then rinsed and dried, and bonding agents were applied on tooth surface. As shown in [Figure 1], [Figure 2], [Figure 3], [Figure 4].
Figure 1: Armamentarium

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Figure 2: Grouping of samples

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Figure 3: Labial surface reduced at a depth of 1.5 mm using 245 carbide bur

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Figure 4: Armamentarium testing machine

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Then, the composite resin (Z-350 XT, 3M ESPE) was placed in a two-layer increment on tooth in silico ne rubber mold (2 mm × 2.5 mm) and was light cured (Woodpecker Led) for 40 s. The samples were thermocycled at a temperature 5°C–55°C at a dwell time of 30 s. In distilled water, all the specimens were stored for 24 h before shear bond testing. Specimens were subjected to the universal testing machine in a compression mode force at a crosshead speed of 1 mm/min keeping blade parallel to the adhesive–dentin interface. Shear force required to debond the specimen was then recorded. Debonding stress was calculated in megapascal (MPa) by the ratio of maximum load in newton to the surface area of prepared resin cylinder (Mpa + N/mm2). The data so obtained were then tabulated and analyzed statistically using ANOVA and post hoc test.


   Results Top


A significant difference was noted in the shear bond strength to dentin of four self-etch adhesives tested. The pH value did not influence the shear bond strength significantly in the tested adhesive systems. ADPER EASY ONE (pH= 2.3, GROUP C Seventh Generation) showed higher bond strength followed by XENO IV(pH = 2.1, GROUP D), XENO III (pH = 1.5, GROUP B) on dentinal surface, where as ADPER PROMPT L POP (pH =0.7 to 1 Sixth Generation, GROUP A) showed lower bond strength. Based on this result, it appears that seventh generation is beneficial than sixth generation in dentin bonding as it has fewer steps and higher shear bond strength, as shown in [Table 1] and [Table 2]. As shown in [Graph 1] and [Graph 2].
Table 1: Summary of Shear bond strength (Mpa) scores in four groups

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Table 2: Comparison of four groups with respect to Shear bond strength (Mpa) scores by one way ANOVA

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   Discussion Top


Dentin is a dynamic tissue that comprises the major part of the tooth. most adhesive procedures in dentistry involve bonding to dentin, to create a strong bond between resin and dentin adequate hybrid Layer formation is essential this bond between dentin and resin adhesive system enhances good marginal adaptation, thereby preventing recurrent caries, microleakage, and pulpal irritation.

To withstand stress generated by Polymerization shrinkage in composite material shear bond strengths of 17–21 MPa value is required. Hence, dental adhesive systems are used to promote adhesion between dental structure and composite resin.[4]

The present study compared shear bond strength of sixth-generation APLP (3M ESPE) and X III (Dentsply) and seventh-generation AEO (3M ESPE) and X IV (Dentsply) adhesives to dentin.

The newer self-etching adhesives are more advantages as these system include infiltration of the bonding agent into the demineralized dentin and a decreasing the number of clinical procedural steps. The interaction depth of self-etch adhesives at dentin differs from a few hundreds of nanometers depending on the pH of the self-etch solutions.[5],[6]

As self-etch adhesives are less acidic, hence they demineralize dentin more superficially than total-etch adhesives. The pH of self-etch adhesives is higher than that of phosphoric acid.

Depending on etching aggressiveness, self-etch adhesives are also classified into three categories based on their pH value: mild (pH of 2.5 or more) demineralize dentin superficially at a depth of 1.0micron meter and create a thinner transitional layer, moderate (pH of approximately 1), and strong (pH <1) dissolve the smear layer completely and form a relatively thick transitional layer.[7]

In the present study, it was observed that pH values did not influence the shear bond strength significantly in the tested adhesive systems. ADPER EASY ONE (pH= 2.3, GROUP C Seventh Generation) showed higher bond strength followed by XENO IV(pH = 2.1, GROUP D), XENO III (pH = 1.5, GROUP B) on dentinal surface, where as ADPER PROMPT L POP (pH =0.7 to 1 Sixth Generation, GROUP A) showed lower bond strength. APLP (Group A) and X III (Group B) have pH values of less than 1 and 1.4, respectively, and thus are characterized as “strong self-etch” and “intermediary strong self-etch” adhesives. Low bond strength values are present with low-pH self-etching adhesives to dentin due to their initial high acidity that causes deep demineralization.

AEO (Group C) and X IV (Group D) the pH is much higher; hence, they are mild self-etching adhesive; they demineralize dentin upto a depth of 1 μm. They preserve residual hydroxyapatite attached to collagen, and sufficient surface porosity is achieved for micromechanical interlocking through hybridization.[8]

The hybrid layer thickness is much smaller in mild self-etching adhesive than strong self-etch or etch-and-rinse approach. but thickness is of minor importance with regard to bonding effectiveness.[9]

Additional chemical bonding is achieved by the preservation of hydroxyapatite within the submicron hybrid layer. Higher bond strength is found to have mild self-etching adhesives.

This might be a probable explanation for low bond strength of APLP and X III compared to AEO and X IV.

APLP is a self-etch adhesive composed of Liquid 1 (red blister): methacrylate phosphoric acid, bis-GMA initiators, stabilizers Liquid 2 (yellow blister): water, 2-hydroxyethyl methacrylate (HEMA) polyalkenoic acid, stabilizers.[10],[11]

However, residual water that remains within the adhesive interface is of a concern because it is hardly removed.

APLP has only water as a solvent, and residual water can be a reason for its low bond strength causing polymerization inhibition, phase separation, and reduced shelf life.

Furthermore, water is a poor solvent for organic compounds such as monomers.[12],[13]

APLP have (pH = 1) and is considered as strong self-etch adhesive, have shown low bond strength value; this might be because of the absence of solvent. This can be overcomed by addition of ethanol a secondary solvent, which causes displacement of residual water and carries the polymerizable monomers into the opened dentin tubules. AEO, X III, and X IV have additional solvent ethanol in it.[14],[15],[16]

X III, a one-step self-etch adhesive composed of HEMA, ethanol, 2,6-di-tert-butyl-p-hydroxytoluene, nanofiller, urethane dimethacrylate (UDMA) Bisphenol-A-glycidyl dimethacrylate (BHT) camphorquinone, ethyl benzoate, and two new pyro-EMA and PEM-F demonstrated fairly bond strength values with dentin.[10],[17]

Van Meerbeek et al. credited the good bond strength values with X III because it is an intermediate strong self-etch adhesive, with an acidic pH of 1.4, and this property results in better micromechanical interlocking to enamel and dentin in comparison to mild self-etch adhesives.[18]

Furthermore, X III has a high viscosity, which can further decrease bond strength. Insufficient primer drying time reduces bond strength for self-etch adhesives, especially water-based system. Two-step self-etch adhesive systems have been reported to yield higher bond strengths compared to one-step self-etch adhesive systems, due to varying measurement of their chemical constituents. Both contain cross-linking monomers, functional monomers, solvent, inhibitors, and activators but in varying proportions.[19]

Less cross-linking monomers were seen with one-step self-etch adhesive systems. These cross-linking monomers provide more mechanical strength.[20],[21],[22]

The result of the present study revealed that there was a significant difference in the in vitro dentin shear bond strength among the self-etching adhesives tested.


   Conclusion Top


The pH values did not influence the shear bond strength significantly in the tested adhesive system. AEO (pH = 2.3, Group C seventh generation) showed higher bond strength than all the tested groups.


   Results Top


In the present study, pH value did not influence the shear bond strength significantly in the tested adhesive systems. AEO (pH = 2.3, Group C seventh generation) showed higher bond strength.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
   References Top

1.
Eakle WS. Fracture resistance of teeth restored with class II bonded composite resin. J Dent Res 1986;65:149-53.  Back to cited text no. 1
    
2.
Buonocore MG. A simple method of increasing the adhesion of acrylic filling materials to enamel surfaces. J Dent Res 1955;34:849-53.  Back to cited text no. 2
    
3.
Buonocore MG, Matsui A, Gwinnett AJ. Penetration of resin dental materials into enamel surfaces with reference to bonding. Arch Oral Biol 1968;13:61-70.  Back to cited text no. 3
    
4.
Buonocore MG. Principles of adhesive retention and adhesive restorative materials. J Am Dent Assoc 1963;67:382-91.  Back to cited text no. 4
    
5.
Duke ES. Adhesion and its application with restorative materials. Dent Clin North Am 1993;37:329-40.  Back to cited text no. 5
    
6.
McLean JW. A clinical and pathological evaluation of a sulphinic acid activated resin for use in restorative dentistry. Br Dent J 1952;93:255-69.  Back to cited text no. 6
    
7.
Nakabayashi N, Kojima K, Masuhara E. The promotion of adhesion by the infiltration of monomers into tooth substrates. J Biomed Mater Res 1982;16:265-73.  Back to cited text no. 7
    
8.
Duke ES, Lindemuth J. Variability of clinical dentin substrates. Am J Dent 1991;4:241-6.  Back to cited text no. 8
    
9.
Gandhi RV.In vitro Evaluation of Shear Bond Strength of Self Etching Primers to Dentin (Doctoral dissertation).  Back to cited text no. 9
    
10.
Van Meerbeek B, De Munck J, Yoshida Y, Inoue S, Vargas M, Vijay P, et al. Buonocore memorial lecture. Adhesion to enamel and dentin: current status and future challenges. Oper Dent 2003;28:215-35.  Back to cited text no. 10
    
11.
Sano H, Shono T, Takatsu T, Hosoda H. Microporous dentin zone beneath resin-impregnated layer. Oper Dent 1994;19:59-64.  Back to cited text no. 11
    
12.
Tay FR, Gwinnett JA, Wei SH. Micromorphological spectrum from overdrying to overwetting acid-conditioned dentin in water-free acetone-based, single-bottle primer/adhesives. Dent Mater 1996;12:236-44.  Back to cited text no. 12
    
13.
Perdigão J, Lopes M. Dentin bonding--questions for the new millennium. J Adhes Dent 1999;1:191-209.  Back to cited text no. 13
    
14.
Haller B. Recent developments in dentin bonding. Am J Dent 2000;13:44-50.  Back to cited text no. 14
    
15.
Carvalho RM, Chersoni S, Frankenberger R, Pashley DH, Prati C, Tay FR. A challenge to the conventional wisdom that simultaneous etching and resin infiltration always occurs in self-etch adhesives. Biomaterials 2005;26:1035-42.  Back to cited text no. 15
    
16.
Nair M, Paul J, Kumar S, Chakravarthy Y, Krishna V, Shivaprasad. Comparative evaluation of the bonding efficacy of sixth and seventh generation bonding agents: An In-Vitro study. J Conserv Dent 2014;17:27-30.  Back to cited text no. 16
[PUBMED]  [Full text]  
17.
Perdigão J, Frankenberger R, Rosa BT, Breschi L. New trends in dentin/enamel adhesion. Am J Dent 2000;13:25D-30D.  Back to cited text no. 17
    
18.
Nikaido T, Nakajima M, Higashi T, Kanemura N, Pereira PN, Tagami J. Shear bond strengths of a single-step bonding system to enamel and dentin. Dent Mater J 1997;16:40-7.  Back to cited text no. 18
    
19.
Lührs AK, Guhr S, Schilke R, Borchers L, Geurtsen W, Günay H. Shear bond strength of self-etch adhesives to enamel with additional phosphoric acid etching. Oper Dent 2008;33:155-62.  Back to cited text no. 19
    
20.
Moura SK, Reis A, Pelizzaro A, Dal-Bianco K, Loguercio AD, Arana-Chavez VE, et al. Bond strength and morphology of enamel using self-etching adhesive systems with different acidities. J Appl Oral Sci 2009;17:315-25.  Back to cited text no. 20
    
21.
Tsai YL, Nakajima M, Wang CY, Foxton RM, Lin CP, Tagami J. Influence of etching ability of one-step self-etch adhesives on bonding to sound and non-carious cervical sclerotic dentin. Dent Mater J 2011;30:941-7.  Back to cited text no. 21
    
22.
Hegde MN, Hegde P, Shetty SK. The influence of salivary contamination on the shear bond strength of two newer generation dentin bonding agents-An in vitro study. J Conserv Dent 2008;11:127-30.  Back to cited text no. 22
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Correspondence Address:
Dr. Asim Jamadar
Department of Conservative Dentistry and Endodontics, Maratha Mandal Nathagirao G Halgekar Institute of Dental Sciences and Research Centre, Bauxite Road Opposite, APMC Police Station, Belgaum - 590 010, Karnataka
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/JCD.JCD_543_19

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