Journal of Conservative Dentistry
Home About us Editorial Board Instructions Submission Subscribe Advertise Contact e-Alerts Login 
Users Online: 1037
Print this page  Email this page Bookmark this page Small font sizeDefault font sizeIncrease font size
 


 
Table of Contents   
ORIGINAL ARTICLE  
Year : 2012  |  Volume : 15  |  Issue : 4  |  Page : 383-387
The effect of surface treatments and bonding regimens on microtensile bond strengths of repaired composite: An in vitro study


Department of Conservative Dentistry and Endodontics, JSS Dental College, Mysore, India

Click here for correspondence address and email

Date of Submission04-Jan-2012
Date of Decision19-Mar-2012
Date of Acceptance23-Jul-2012
Date of Web Publication3-Oct-2012
 

   Abstract 

Aim: To assess the microtensile bond strength of repaired composite resin that was surface treated by diamond point or silicon carbide followed by bonding using either only total- etch bonding regimen or silane coupling agent with adhesive resin.
Materials and Methods: Fourteen composite blocks were aged under deionized water for 14 days. The bonding surface was prepared with coarse diamond point or silicon carbide. Two blocks with no surface treatment were used as control groups. The bonding regimen was either total-etch bonding regimen or silane coupling agent and bonding agent. The aged samples were then bonded to new composite. Five sections per block (each 1mm thick) were prepared; cut to obtain an adhesive zone of approximately 1mm 2 and subjected to microtensile bond strength testing.
Results: The highest bond strength was obtained by surface treatment by coarse diamond point and total etch bonding regimen and least by silicon carbide and silane. A statistically significant difference was seen in all the four groups.
Conclusions: Surface treatment by a coarse diamond point and total-etch bonding regimen provides highest bond strength. Thus, a simpler treatment regimen can contribute to a better bond strength in repaired composites.

Keywords: Microtensile bond strength; repaired composite resin; silane primer; total-etch bonding agent

How to cite this article:
Acharya GS, Manjunath M K. The effect of surface treatments and bonding regimens on microtensile bond strengths of repaired composite: An in vitro study. J Conserv Dent 2012;15:383-7

How to cite this URL:
Acharya GS, Manjunath M K. The effect of surface treatments and bonding regimens on microtensile bond strengths of repaired composite: An in vitro study. J Conserv Dent [serial online] 2012 [cited 2019 Apr 20];15:383-7. Available from: http://www.jcd.org.in/text.asp?2012/15/4/383/101919

   Introduction Top


Resin based dental composites are gaining a wide acceptance in today's dental practice. [1]

In clinical practice, composite is exposed to atmospheric oxygen creating an oxygen-inhibited layer. [2],[3] This layer is viscous and contains unreacted C=C bonds. The unreacted C=C bonds of the functional groups on the surface of a polymerized matrix will allow the monomer of new resin composite to bond, thereby improving adhesion. [4]

But, over time these materials undergo degradation and deterioration in the intra-oral environment. [5] These processes lead to fracture or defects of the composite restoration either at the composite-tooth interface or within the restorative material itself. [6]

For years, the traditional management consisted of replacing entire restorations. [7],[8] More recently a minimally invasive operative philosophy that aims to repair such defects; which is more conservative, less traumatic to pulp, less time consuming and more cost-efficient or at least can be used as an acceptable interim procedure until further treatment has become a viable option. [9]

Due to of limited number of reactive methacrylate groups after polymerization and water sorption into pre-existing composite, the repaired composite cannot effectively bond to the aged composite restoration without adequate surface treatment. [10] In such cases, providing sufficient bonding to the old restoration is important, and can be achieved either mechanically or chemically. [11]

Though studies have been undertaken to find out optimal repair protocols using different bonding techniques; there exists a wide gap between experimental methods and those used in daily restorative practice. [12],[13]

Hence, in the present study surface treatment by Diamond point and Silicon carbide, which are most widely used for finishing composites are compared along with total etch bonding regimen and silane coupling agent with bonding agent.


   Materials and Methods Top


Fourteen composite blocks of a microhybrid composite resin (Esthet X HD; Dentsply India) {Shade B 2} were made; each measuring 8 mm × 8 mm × 6 mm using Teflon molds. From each block; 5 samples was prepared. They were stored in deionized water at 37°C for 14 days for aging. It was then categorized into 1 control (2 blocks) and 2 experimental groups (6 blocks for each group).

The grouping of samples is as follows:

Group A (Control group) (n=10)-No surface treatment

Subgroup A1 (n=5)- The bonding surface was etched (Frost; Ammdent, India) and bonding agent (Adper Single Bond; 3M, ESPE, USA) applied.

Subgroup A2 (n=5)- Bonding surface was treated with silane primer (Rely X Ceramic Primer; 3M, ESPE, USA) and bonding agent applied.

Group B (Experimental group) (n=30)-Coarse Diamond point {(125 μm to 150 μm); Mani Inc, Japan} was used for surface treatment. Surface was abraded two times for 5 sec by the same operator to maintain standardization.

Subgroup B1 (n=15)- Etching and application of bonding agent.

Subgroup B2 (n=15)- Application of Silane primer and bonding agent.

Group C (Experimental group) (n=30)- Silicon carbide {(Green carborundum stone); Shofu Dental corporation, Japan} was used for surface treatment. Surface was abraded two times for 5 sec by the same operator to maintain standardization.

Subgroup C2 (n=15) - Application of Silane primer and bonding agent.

After surface treatment the blocks were subjected to ultrasonic cleaning for 10 mins to remove surface debris and ensure proper adhesion of composite.

Following the surface treatments and bonding regimen applications, the aged composite blocks (Shade B2) were bonded to new composite (Shade A3.5). An increment of 2 mm was obliquely layered and light cured using a halogen light-curing unit. (Translux Energy, Heraeus KulzerInc, Germany) for 20 sec per increment at 600 mW/cm 2 .

5 Sections per block each (thickness of per section-1mm) were prepared by a slow speed diamond saw (Isomet saw; Buehler Lake Bluff, Illinois, USA). Hourglass shaped specimens with a cross-sectional area of 1 mm 2 were made and subjected to microtensile bond strength in a universal tester (Instron 3365).

Results were statistically analyzed using one way ANOVA and independent t-test


   Results Top


The results of the microtensile bond strength are summarized in [Table 1]. A comparison between various groups is depicted in [Table 2]. [Table 3], [Table 4], [Table 5], [Table 6], [Table 7], [Table 8] and [Table 9] denote the individual comparisions between two subgroups. [Figure 1] shows the comparative evaluation of all the six subgroups.
Figure 1: Comparison of control and experimental subgroups

Click here to view
Table 1: Means, SD, Minimum and Maximum load for different subgroups

Click here to view
Table 2: One way ANOVA values

Click here to view
Table 3: t-test value for comparison between Subgroup A1 and Subgroup A2

Click here to view
Table 4: t-test value for comparison between Subgroup A1 and Subgroup B1

Click here to view
Table 5: t-test value for comparison between subgroup A1 and subgroup C1

Click here to view
Table 6: Test value for comparison between subgroup A2 and subgroup B2

Click here to view
Table 7: t-test value for comparison between subgroup A2 and subgroup C2

Click here to view
Table 8: t-test value for comparison between subgroup B1 and subgroup B2

Click here to view
Table 9: t-test value for comparison between subgroup C1 and subgroup C2

Click here to view



   Discussion Top


Resin-based composites are widely employed in dentistry since the advent of adhesive technologies. [14] Adhesive dentistry brought into perspective the possibility of a more conservative approach for tooth restoration, based on the reduction of the cavity preparation size and the bonding of the restorative material (resin-based composite) to tooth structure. It led to more cohesive failures rather than adhesive failures. [15]

Hence, a feasible treatment option of such failed restorations can be the repair of just that failed part; rather than the replacement of the entire restoration. Repair preserves the sound tooth structure that would be at risk during replacement of the restoration and also prevents repeated trauma to the pulp-dentin organ.

However, repair of an existing restoration is also not bereft of all flaws. The substrate to be bonded is a chemically degraded one with no free radicals to bond to another layer of fresh composite. Commercially the available bonding systems; rely on primarily adhesion to either enamel or dentin with none, formulated specifically to bond to the non-mineralized aged resin-based composite substrate.

Bonding to this substrate depends on various surface roughening techniques such as with air abrasion, diamond points or acids and the use of intermediary agents such as adhesive resins and Silane primer. [9]

The resin composite used in this study (Esthet X HD) is a microhybrid composite with a particle size of 0.6 to 0.8 μm and loading 77% (by wt %) or 60% (by vol %). It belongs to one of the most commonly used resin composite family, and has been claimed by manufacturers to be used as an universal restorative material (for both anterior and posterior restorations).

Various techniques have been utilized to simulate the intra-oral aging conditions. [12],[16],[17],[18] Among all methods, aging due to immersion in water has generated maximum research and is most commonly seen in oral cavity. [19] Water diffusion through the polymer chains and boundaries with fillers and the hydrolytic deterioration of the polymer chains resulted in elution of components and the plasticization of the composite. Initially, this process would affect surface properties, such as hardness and wear resistance. However, with time, it also interferes with the bulk properties, such as the strength and fracture toughness of the material thereby, compromising the long-term durability of the restoration. [20],[21],[22] Hence, in this study, aging by immersion in water for 14 days was used.

It is rather easy to bond to fresh composite, which is covered by an oxygen inhibition layer, because a covalent bond is established between the uncured surface layer and the newly applied composite material. Aged composite materials lack this zone, and hence other viable alternatives to facilitate bonding of the new materials with the aged composite needs to be investigated.

In this study, three different surface treatments and bonding regimens were applied according to various alternatives; [23],[24],[25]

Creating a micro-mechanical locking substrate using a coarse Diamond point or Silicon carbide.

Forming a potential interpenetrating network using a total-etch bonding regimen.

Creating chemical bond to the surface of exposed glass filler surfaces by application of silane to the surface.

Although, the effect of different contemporary chemical and mechanical treatment procedures on the repair bond strength of aged composite were evaluated previously, the choice of the different chemical and mechanical repairing procedures in this study were aimed to evaluate the validity of the simplest and most common methods that were used in every day clinical practice.

Defects in the old composite resin restorations may be restricted only to the old composite resin or may involve the composite resin and the adjacent tooth structure as well. When such defect involves both the restoration and the tooth, additional preparations in the form of removal of discolored or carious tooth tissues and/or bevel preparation is recommended. In the daily dental practice, such preparations are usually done using rotary cutting instruments.

In this study, two different abrasives have been used:

  1. Coarse diamond point.
  2. Silicon carbide.
The micro-mechanical roughening produced by these abrasives depends on the abrasive particle size. Silicon carbide is 29 μm and coarse Diamond point is 125-150 μm. Hence, more surface roughness is expected of the coarse Diamond point. This explains the higher bond strength obtained by groups using coarse Diamond point.

After surface treatment the blocks were subjected to ultrasonic cleaning for 10 mins. This was done to remove any superficial debris produced by the mechanical roughening, which might hinder the bonding to aged composite resin.

The highest repair bond strength obtained by the use of total-etch bonding systems can be attributed to:

The unfilled resins in the bonding agent penetrated into the roughened composite surface, creating a new oxygen inhibited layer.

The bonding agent formed covalent hydrogen bonds to the silane in the inorganic filler particles.

In the present study, silane pretreatment has shown lower bond strength when compared to Total-etch bonding regimen and can be attributed to: [25]

Mechanism through which fillers react when mechanically loaded, aged or abraded is by breaking off in clusters. This loss of fillers might reduce interaction with silanes and thus decrease the bond strength.

Incomplete solvent evaporation during air-drying may occur resulting in increased viscosity of the adhesive blend exerting an adverse effect on the polymerization.

Because of surface treatment; the silane layer on any remaining filler is depleted. Thus, chemical adhesion of the unpolymerized resin matrix to these inorganic particles was unlikely.

Following the surface treatments and bonding regimen applications, the aged composite blocks (Shade B2) were bonded to new composite (Shade A3.5). Contrasting shades were used to obtain an easily recognizable adhesive zone. This made it easier to prepare an hour-glass shaped specimen by cutting along this adhesive zone or interface.

Considering the afore-mentioned facts, surface treatment by coarse Diamond point followed by etching and bonding resin application produces the highest microtensile bond strength in comparison to either surface treatment by silicon carbide or application of Silane primer. From a clinical point of view this might be advantageous, since the use of silane may interfere with composite bond to enamel and /or to dentin exposed at the repair site.

However, in applying the findings of an in vitro study to a clinical situation, it is important to realize that the two situations are widely different and may not co-relate completely. Therefore, further in vivo studies have to be conducted.

I affirm that, I have no financial affiliation (e.g., employment, direct payment, stock holdings, retainers, consultantships, patent licensing arrangements or honoraria), or involvement with any commercial organization with direct financial interest in the subject or materials discussed in this manuscript, nor have any such arrangements existed in the past 3 years. Any other potential conflict of interest is disclosed.


   Conclusion Top


Within the limitations of this study it can be concluded that:

Bond strength obtained by surface treatment with coarse Diamond point is significantly higher than that obtained by surface treatment with Silicon carbide.

Total-etch bonding regimen produces higher bond strength compared to treatment with Silane primer and Bonding resin application.

The highest bond strength is achieved by surface treatment with coarse Diamond point followed by application of Total-etch bonding regimen.

 
   References Top

1.El-Askary FS, Fawzy AS, AbdElmohsen HM. Tensile bond strength of immediately repairedanterior microfine hybrid restorative composite using non trimmed hourglass specimens. J Adhes Dent2009;11:41-7.  Back to cited text no. 1
    
2.Rinastiti M, Ozcan M, Siswomihardjo W, Busscher HJ. Immediaterepair bond strengths of microhybrid, nanohybridandnano filled composites after different surface treatments. J Dent2010;38:29-38.  Back to cited text no. 2
[PUBMED]    
3.Li J. Effect of surface properties on bond strength between layers of newlycured dental composites. J Oral Rehabil 1997;24:358-60.  Back to cited text no. 3
[PUBMED]    
4.Fawzy AS, El-Askary FS, Amer MA. Effect of surface treatments on the tensile bond strength of repaired water-age danterior restorative micro-fine hybrid resin composite. J Dent 2008;36:969-76.  Back to cited text no. 4
[PUBMED]    
5.Rinastiti M, Ozcan M, Siswomihardjo W, Busscher HJ. Effects ofsurface conditioning on repair bond strengths of non-aged andaged microhybrid, nanohybrid, and nano filled composite resins. Clin Oral Investig 2011;15:625-33.  Back to cited text no. 5
[PUBMED]    
6.Ferracane JL. Hygroscopic and hydrolytic effects in dental polymer networks. Dent Mater 2006;22:211-22.  Back to cited text no. 6
[PUBMED]    
7.Gordan VV, Garvan CW, Blaser PK, Mondragon E, Mjor IA. A long-term evaluation of alternative treatments to replacement of resin-based composite restorations: Results of a seven-year study. J Am Dent Assoc 2009;140:1476-84.  Back to cited text no. 7
    
8.Gordan VV. Clinical evaluation of replacement of class V resin based composite restorations. J Dent 2001;29:485-8.  Back to cited text no. 8
[PUBMED]    
9.Bonstein T, Garlapo D, Donarummo Jr J, Bush JP. Evaluation of varied repaired protocols applied to aged composite resin. J Adhes Dent 2005;7:41-9.  Back to cited text no. 9
    
10.Loomans BA, Cardoso MV, Roeters FJ, Opdam NJ, De Munck J, Huysmans MC,et al. Is there one optimal repair technique for all composites? Dent Mater 2011;27:701-9.  Back to cited text no. 10
[PUBMED]    
11.Rodrigues SA Jr, Ferracane JL, Della Bona A. Influence of surface treatments on the bondstrength of repaired resin composite restorative materials.Dent Mater2009;25:442-51.  Back to cited text no. 11
[PUBMED]    
12.Shahdad SA, Kennedy JG. Bond strength of repaired anterior composite resins: An in vitro study.J Dent1998;26:685-94.  Back to cited text no. 12
[PUBMED]    
13.Padipatvuthikul P, Mair LH.Bonding of composite to water aged composite with surface treatments.Dent Mater 2007;23:519-25.  Back to cited text no. 13
[PUBMED]    
14.Ozcan M, Barbosa SH, Melo RM, Galhano GA, Bottino MA. Effect of surface conditioning methods on the micro tensile bond strength of resin composite to composite after aging conditions.Dent Mater 2007;23:1276-82.  Back to cited text no. 14
[PUBMED]    
15.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. 15
[PUBMED]    
16.Miranda WG, Placido E, Moura SK, Cardoso PE. Influence of postextraction substrate aging on the microtensile bond strength of a dental adhesive system. J Adhes Dent2005;7:193-6.  Back to cited text no. 16
[PUBMED]    
17.Reis AF, Giannini M, Pereira PN. Influence of water-storagetime on the sorptionand solubility behavior of current adhesives and primer/ adhesive mixtures.Oper Dent 2007;32:53-9.  Back to cited text no. 17
[PUBMED]    
18.Armstrong SR, Keller JC, Boyer DB. The influence of water storage and C-factor on the dentin-resin composite microtensile bond strength and debond pathway utilizing a filled and unfilled adhesive resin.Dent Mater 2001;17:268-76.  Back to cited text no. 18
[PUBMED]    
19.Pilliar RM, Vowles R, Williams DF. The effect of environmental aging on the fracture toughness of dental composites. J Dent Res 1987;66:722-6.  Back to cited text no. 19
[PUBMED]    
20.Yap AU, Chung SM, Rong Y, Tsai KT: Effects of aging on mechanical properties of composite restoratives: A depth-sensing micro indentation approach. Oper Dent 2004;29:547-53.  Back to cited text no. 20
    
21.Hahnel S, Henrich A, Bürgers R, Handel G, Rosentritt M. Investigation ofmechanicalpropertiesof moderndentalcompositesafter artificial aging for one year. Oper Dent 2010;35:412-9.  Back to cited text no. 21
    
22.Shen C, Mondragon E, Gordan VV, Mjör IA. The effect of mechanical undercuts on the strength of composite repair. J Am Dent Assoc 2004;135:1406-12.  Back to cited text no. 22
    
23.Staxrud F, Dahl JE. Role of bonding agents in the repair of composite resin restorations. Eur J Oral Sci 2011;119:316-22.  Back to cited text no. 23
[PUBMED]    
24.Akimoto N, Sakamoto T, Kubota Y, Kondo Y, Momoi Y. Anovel composite-to-composite adhesive bond mechanism. Dent Mater J 2011;30:523-7.  Back to cited text no. 24
[PUBMED]    
25.Hamano N, Chiang YC, Nyamaa I, Yamaguchi H, Ino S, Hickel R, et al. Effect of different surface treatments on the repair strength of an anofilled resin-based composite. Dent Mater J 2011;30:537-45.  Back to cited text no. 25
[PUBMED]    

Top
Correspondence Address:
Gouri Smita Acharya
C/O Dr. Chinmayi Mohapatra, Sr. Doctors Quarters No.3, Medical Road, Ranihat, Cuttack-753007, Orissa
India
Login to access the Email id

Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0972-0707.101919

Rights and Permissions


    Figures

  [Figure 1]
 
 
    Tables

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7], [Table 8], [Table 9]

This article has been cited by
1 Comparative evaluation of microtensile bond strength of different solvent based one step and two step adhesive systems to dentin. An in-vitro study
Somasundaram, P. and Uthappa, R. and Shivgange, V. and Shivamurthy, G.B. and Shivanna, V.
Journal of Conservative Dentistry. 2013; 16(4): 371-374
[Pubmed]
2 Effect of four different surface treatments on shear bond strength of three porcelain repair systems: An in vitro study
Gourav, R. and Ariga, P. and Jain, A. and Philip, J.
Journal of Conservative Dentistry. 2013; 16(3): 208-212
[Pubmed]



 

Top
 
 
 
  Search
 
 
    Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
    Email Alert *
    Add to My List *
* Registration required (free)  
 


    Abstract
   Introduction
    Materials and Me...
   Results
   Discussion
   Conclusion
    References
    Article Figures
    Article Tables

 Article Access Statistics
    Viewed1741    
    Printed79    
    Emailed0    
    PDF Downloaded173    
    Comments [Add]    
    Cited by others 2    

Recommend this journal