Contemporary Clinical Dentistry
   
  Home | About us | Editorial board | Search
Ahead of print | Current Issue | Archives | Advertise
Instructions | Online submission| Contact us | Subscribe |

 

Login  | Users Online: 3294  Print this pageEmail this pageSmall font sizeDefault font sizeIncrease font size 



 
 Table of Contents  
GUEST EDITORIAL
Year : 2016  |  Volume : 7  |  Issue : 3  |  Page : 291-292  

A discussion on how to apply resin-modified glass ionomers


Department of Operative Dentistry, Dental Materials Research Center; Editor in Chief, Dental Research Journal Torabinejad Dental Research Center, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran

Date of Web Publication17-Aug-2016

Correspondence Address:
Maryam Khoroushi
Department of Operative Dentistry, Dental Materials Research Center; Editor in Chief, Dental Research Journal Torabinejad Dental Research Center, School of Dentistry, Isfahan University of Medical Sciences, Isfahan
Iran
Login to access the Email id

Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0976-237X.188538

Rights and Permissions

How to cite this article:
Khoroushi M. A discussion on how to apply resin-modified glass ionomers. Contemp Clin Dent 2016;7:291-2

How to cite this URL:
Khoroushi M. A discussion on how to apply resin-modified glass ionomers. Contemp Clin Dent [serial online] 2016 [cited 2020 Jan 27];7:291-2. Available from: http://www.contempclindent.org/text.asp?2016/7/3/291/188538




Resin-modified glass ionomers (RMGIs) have been introduced to dentistry as materials which have the advantages of composite resins and glass ionomers at the same time. These materials have an acid-base reaction due to their glass ionomer nature and can form a chemical bond with the substrate. [1] They have the advantage of releasing fluoride and are recommended for use on the gingival floor of deep Cl II and Cl V cavities in which there is proximity to dentinal and cemental substrates in the bonded base technique. [2] RMGLs might decrease the incidence of recurrent caries and polymerization shrinkage stress of composite resins. [2],[3],[4] On the other hand, these materials have adequate strength as a base material beneath composite resins and amalgam due to their resin nature and in some cases, such as conservative cavities, they can be used to restore the whole cavity. [1],[3]

In relation to polymerization, the resin component of these materials can exhibit two types of polymerization: Photoinitiated and chemical; if both types of polymerization are involved, the curing process will be three-fold by taking account of the acid-base reaction. [1],[4] The majority of these materials exhibit photoinitiated polymerization in addition to the acid-base reaction; in such cases, the curing will be dual because self-curing properties do not exist. The curing rate of some of these materials has been promoted by incorporating calcium aluminate into their chemical structure, and in the self-cured versions which have a high curing rate such a process has been used in the curing process. [4] Therefore, the operator should know that not all the RMGI's have a light-curing mechanism for polymerization. In some commercial products, these materials exhibit shrinkage up to 3% and in some cases, shrinkage rates more than those of composite resins have been reported. [5] In recent years, in some studies, a kind of network competition has been reported during curing processes, i.e., a delay in light-curing might increase the rate of acid-base reaction; on the contrary, light curing of these materials immediately after their placement in the cavity might limit the formation of resin chains of the acid-base reaction. [6]

From a clinical point of view, some of these materials have special conditioners or primers used before their placement in the cavity to modify the smear layer and prepare the surface of the substrate for bonding. However, some others are used without conditioning the tooth surface. [5] Recently, some studies have reported that the use of an adhesive, especially self-etch adhesives, results in an improvement in marginal integrity and bond strength of these materials in deep cervical cavities. [7],[8],[9] However, these adhesives might prevent or limit the release of fluoride in the substrate beneath the resin. [5]

On the other hand, current light curing units convey a wide range of spectral emissions and irradiance levels. These differences among the different units are often not perceivable by the eye nor accurately by a radiometer; however, they can affect the polymerization of the resin based materials. [10] The best and most efficient range of wavelengths of light, intensity, and exposure time with each of the light curing device is unknown, particularly for RMGIs.

The question is whether it is advisable for manufacturers to provide users with more information about the commercial products to achieve more favorable clinical results so that the clinical behaviors will be adjusted to the nature of the materials and the dentists will resolve ambiguities and will avoid carrying out some procedures through trial and error to achieve more favorable clinical results. Since such materials have the dual resin/glass ionomer nature, it appears each of these two natures affects their behaviors and physico-mechanical properties, including shrinkage. Isn't it high time the users received more explanations about these materials, the rate of their resin and glass ionomer components and the amount of fluoride released by them? Moreover, isn't it high time the manufacturers provided the clinicians with information on such matters?

When the clinician uses these materials in the clinic, he/she should ask him/herself these questions: Does the material have adequate glass ionomer properties so that a delay in photoinitiated polymerization can increase the rate of acid-base reaction with the underlying substrate? Can the substrate benefit sufficiently from the release of fluoride? Does the material have adequate resin nature so that a higher bond strength and more appropriate marginal integrity can be achieved with the use of an adhesive instead of the conventional conditioning or simple irrigation, the choice depending on the manufacture's recommendation? Is the resin nature of the commercial product used adequate so that the effect of the use of dental adhesive on the release of fluoride can be ignored in favor of less microleakage? How much polymerization shrinkage will the material exhibit with self-curing or photoinitiated curing? Does the amount of shrinkage necessitate measures on the gingival floor, such as the use of composite resins similar to that with the incremental technique? It appears there are more questions in this respect, which should be answered by purposeful studies and at least information should be provided in the instruction manuals of commercial products so that they can serve as good guides for the proper clinical use of these materials.

 
   References Top

1.
Cardoso MV, Delmé KI, Mine A, Neves Ade A, Coutinho E, De Moor RJ, et al. Towards a better understanding of the adhesion mechanism of resin-modified glass-ionomers by bonding to differently prepared dentin. J Dent 2010;38:921-9.  Back to cited text no. 1
    
2.
Naoum SJ, Mutzelburg PR, Shumack TG, Thode DJ, Elizabeth Martin F, Ellakwa A. Reducing composite restoration polymerization shrinkage stress through resin modified glass ionomer based adhesives. Aust Dent J 2014 Dec 5. Doi: 10.1111/adj.12265.  Back to cited text no. 2
    
3.
Pontes DG, Guedes-Neto MV, Cabral MF, Cohen-Carneiro F. Microleakage evaluation of class V restorations with conventional and resin-modified glass ionomer cements. Oral Health Dent Manag 2014;13:642-6.  Back to cited text no. 3
    
4.
Anusavice KJ, Phillips RW, Shen C, Rawls HR. Phillips Science of Dental Materials. 12 th ed. St. Louis: Elsevier Science; 2013.  Back to cited text no. 4
    
5.
Berzins DW, Abey S, Costache MC, Wilkie CA, Roberts HW. Resin-modified glass-ionomer setting reaction competition. J Dent Res 2010;89:82-6.  Back to cited text no. 5
    
6.
Khoroushi M, Karvandi TM, Kamali B, Mazaheri H. Marginal microleakage of resin-modified glass-ionomer and composite resin restorations: Effect of using etch-and-rinse and self-etch adhesives. Indian J Dent Res 2012;23:378-83.  Back to cited text no. 6
[PUBMED]  Medknow Journal  
7.
Shafiei F, Akbarian S. Microleakage of nanofilled resin-modified glass-ionomer/silorane- or methacrylate-based composite sandwich class II restoration: Effect of simultaneous bonding. Oper Dent 2014;39:E22-30.  Back to cited text no. 7
[PUBMED]    
8.
Khoroushi M, Mansoori-Karvandi T, Hadi S. The effect of pre-warming and delayed irradiation on marginal integrity of a resin-modified glass-ionomer. Gen Dent 2012;60:e383-8.  Back to cited text no. 8
    
9.
Khoroushi M, Karvandi TM, Sadeghi R. Effect of prewarming and/or delayed light activation on resin-modified glass ionomer bond strength to tooth structures. Oper Dent 2012;37:54-62.  Back to cited text no. 9
    
10.
Price RB, Shortall AC, Palin WM. Contemporary issues in light curing. Oper Dent 2014;39:4-14.  Back to cited text no. 10
[PUBMED]    




 

Top
 
  Search
 
    Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
    Access Statistics
    Add to My List *
* Registration required (free)  

 
  In this article
    References

 Article Access Statistics
    Viewed1604    
    Printed11    
    Emailed0    
    PDF Downloaded209    
    Comments [Add]    

Recommend this journal