Is there any limitation in Ionomer?

Author: Dr Hicham Nuaimi & Dr Hakan Kamlak

Abstract:

Glass ionomer was used in dentistry before 1970, but it has so poor physical properties but it has high fluoride release, in addition to chemical bonding and derivation uses for this magic material in different protocols. Glass ionomer cement composed of a calcium – alumino – silicate glass powder and an aqueous solution of an acrylic acid copolymer. Scientists are dealing to enhance and improve this restorative materials in different protocols with its positivity of fluoride release by using nano particles, Bioactive materials and finally they entered Zirconia metal with GIC to be one of the best dentistry restorative material. Development in GIC is continuing till reaching one day to perfect restoration material.

Keywords: Glass ionomer, RMGIC, Giomer, Zircomer

*BDS, High specialist Diploma Restorative and Aesthetic, High specialist Diploma Implantology, MsC in Restorative and Aesthetic. Lecturer in Conservative Department, Ishik University, Iraq

 

Introduction

Restorative Materials have current characteristics that particularly used in oral cavity without irritation or toxicity, in addition of proper physical properties that withdraw functional forces. Gold, Amalgam, and resin composites commonly have such characteristics. Recently Researchers were invented (smart) materials as Glass Ionomer, which become widely used nowadays and then started to enhance physical properties of this material, (1). Conventional Glass ionomer cement (GIC) is essentially based into powder (calcium aluminum fluorosilicate glass) and liquid (polyacrylic acid), (2). These approaches are apparent for first stimuli to produce active materials, which are biocompatible restorative material according to their interested properties as: fluoride released, proper chemical bonding between each dentin/ enamel, (3) in addition it is biocompatible material by capability of reinforcement of enamel particles by increasing percentage of fluroapatite than hydroxyapatite and prevent accumulation of bacteria on tooth surface by bacteriostatic properties of Fl ions (4), (5). But, it has less physical and esthetic properties than resin based composite, (6), so that a lot of researchers were working to improve this smart material by adding more fillers, using nano technology and using zirconium metal to this Ionomer with caring to esthetic which is the nowadays approach for dental clinic’s patients, (7), (8).

So that this paper focused on Review of this smart material and its update, in addition to its clinical uses.

 

Classifying of glass-ionomer cements

According to Generation:

First generation

In this generation the reaction procedure starts from mixing of glass powder (alumina-silicate) to water. PH of GlC is related to ratio of glass particles it self. Examples of this are ASPA I; its activity was low, high moisture sensitivity in compare with ASPA II, later researchers add tartaric acid to enhance its practical results, (9).

Second generation

In this generation, polyacid liquid was used with alumina- silicate powder so that to enhance the mixing properties and manipulation by increasing shelf life and decrease its viscosity in addition to increase in physical properties. Examples for this generation are Chem-fil and Ketac-Cem, (9).

 

According to Mixture properties:

 

Hydrous

Is the first type invented in dentistry, in which the polyacrylic acid in the liquid component of the GIC when mixed with Powder component of GIC will produce highly viscous, low acidity so that less pulp sensitivity, faster setting and lower solubility when compared to other types. On other side it has thick biofilm so difficult in manipulation (6). Examples are: Chem-bond (DENTSPLY, Germany), GIC type I (Shofu, japan) and old version Fuji I (GC, Japan).

Anhydrous

In this type of GIC, the polyacrylic acid is freeze or vacuum, then dried and add some glass particles to liquid component, later mixed with water. Properties of this type is highly affected by ratio (powder/ liquid), this type has low viscosity, higher acidity that interfere with pulp sensitivity, less soluble, longer shelf life and easier in manipulation. On other side slower initial setting which effect on marginal closure and pulpal sensitivity that may lead in some cases to dead of pulp. Examples are: Chemfil (DENTSPLY, Germany), Ketac- cem (ESPE, Germany).

Semi-hydrous

In this type polyacrylic acid is added in its powder content in addition to liquid. It has moderate viscosity between anhydrous and hydrous types (10), moderate acidity and manipulation. Examples are: Fuji I (GC, japan).

Modification of GIC

According to need for Aesthetic and Functional approach in addition to biocompatible material with bacteriostatic properties, (11), (12) researchers have worked for improvement in strength of GIC to withdraw mastication forces. Efforts have been made for improvement of GIC by modifying the chemical composition of the original glass powder, addition fibers to powder contents, used metal, resin composite and finally using of Zirconium metal with nano technology.

  1. Using Disperse – phase glasses

Researchers were seen that using disperse phase of glass instead of glass particles to strength crystallites by increasing cements of its glass particles itself. Disperse phases that are used in this modified type of GIC are (corundum (Al2O3), rutile (TiO2), (13).

  1. GIC reinforced by Fiber

Modifying using fibers that will increase its physical properties by improvement in flexture strength, on the other hand these fibers may have interfere with manipulation of this product but has low abrasion resistance due to decrease bonding between fiber and matrix, (14).

  1. GIC reinforced by metal

The first step was adding amalgam alloy with GIC during mixing, Simmons invented (Miracle Mix) that showed higher physical properties, flexture strength than conventional GIC. He used this product for core -build up and for treatment of high caries incident patients, in spite there is low aesthetic approach, (15). They’re controversy about abrasion resistance due to failure bonding between metal and its matrix as the fiber problem.

  1. Cermet – ionomer cements

Mclean and Gasser were sintering metal and glass particles together so that strong bond will achieved. Silver alloy, tin, pure silver, titanium, palladium and gold when are treated with aluminum fluorosilicate ions that are leached from glass particles will lead very strong matrix that is called Cermet, (16). This mixture has higher physical properties that withstand to abrasion when compare to other types of GIC, in spite its flexture strength is not equal to that of Amalgam so that it is advised to used in low stress areas, (16).

5- Resin modified glass ionomers cement:

The major withdraw of GIC are still in aesthetic approach, moisture sensitivity and difficulties in manipulation and handled in cavities to be restored. So that researchers were working hard to improve this great biocompatible material by using resin composite instead of metal, fibers, or alloy to solve the aesthetic problem in addition to have the basic advantages of GIC which releasing Fluoride Ions and bacteriostatic in addition easily controlled by light curing process than chemical cure as conventional GIC, (17), (18). This type of GIC is composed of two parts (powder/liquid). In which powder is alumino-flurosilicate glass as photosensitivity with filler of glass that responsible for fluoride release when mixed with water-soluble poly acrylic matrix. While liquid is composed of HEMA, poly acrylic acid that has Methacrylate pendant end to bind with powder during mixing, in addition here is photo accelerators and water. During mixing then light cure activation, the water soluble methacrylate attached with modified polyacrylic acid polymer to create a covalent binding that forms the glass ionomer matrix which makes a durable liner that bond ionically to the tooth structure. Examples of this are Vitrobond (3M ESPE, USA), Fuji Lining LC (GC, Japan).

6- Giomer

Giomer is based on novel PRG technology (Pre-Reacted Glass-ionomer) in which PRG fillers are imbedded in resin matrix. This fillers are consisting of trilaminar structure that has glass core of multifunctional fluoroboroaluminosilicate glass with layer of pre reacted GI and layer of modified layer. This type of Modified GI has ability fluoride release with advantage of recharge without degradation occurred to subsurface of material. In addition it has proper manipulation than other types and smooth surface due to using nano particles and high physical properties so that it can be used in posterior teeth. Example is Beautiful II (Shufo, USA), (19).

7- Zircon Reinforced GIC

Scientists worked hard for improvement GIC. They reinforced GIC by using zirconia fillers in the glass component to show higher mechanical properties to withdraw mastication forces so that it can be used in Posterior teeth and Class I, II and even core build up restoration, where Conventional GIC was less mechanical properties. In addition it has high fluoride release so that it can be used in cases with high caries risks, (19).

Conclusion

Recently due to need for aesthetic and strong restoration in addition to requirement to use easily handled and high fluoride and less polymerization shrinkage that are facing resin based composite, So scientist are working for improvement GIC that were used in pediatric and Geriatricpatients due to decrease chair time consumed. But this step is still in the beginning and recent years will advocated to show more and more in this magic material with resin based composite by adding bioactive and novel monomers to control the prevalence of primary and recurrent caries with less time.

gic

References

x

1. Yli-Urpo H, Lassila L, Narhi T, Vallittu P. Compressive strength and surface characterization of glass ionomer cements modified by particles of bioactive glass. Dent Mater 2005;21:201-9.. Dental Materials. 2005; 21: p. 201-209.
2. AI-Badry I, Kamel F. Clinical use of glass ionomer cement: a literature review. Saudi Dental Journal. 1994; 6(2): p. 107-116.
3. Lucas M, Arita K, Nishino M. Toughness, bonding and fluoride- release properties of hydroxyapatite-added glass ionomer cement.. Biomaterials. 2003; 24: p. 3787-3794.
4. Mousavinasab S, Meyer I. Fluoride release by glass ionomer cements, compomer and giomer. Dental Research Journal. 2009; 6(2): p. 75-81.
5. Forsten L. Fluoride release of glass ionomers. J Esthet Dent 1994;6:216-22.. Journal of Esthetic Dentitsry. 1996; 6: p. 216-622.
6. Lohbauer U. Dental glass ionomer cements as permanent filling materials? – Properties, limitations and future trends. Materials, 3(1): 76-96.. Materials. 2010; 3(1): p. 76-96.
8. McCabe J, Yan Z, Al Naimi O, Mahmoud G, Rolland S. Smart materials in dentistry. Austerialian Dental Journal. 2011; 56: p. 3-10.
7. McCabe J, Yan Z, Al Naimi O, Mahmoud G, Rolland S. Smart materials in dentistry – Future prospects. Dental Material Journal. 2009; 28: p. 37-43.
9. Nagaraja Upadhya P, Kishore G. Glass ionomer cement: The different generations. Trends Biomaterials: Artifitial Organs. 2005; 18: p. 158-65.
10. Smith D, Ruse N. Acidity of glass-ionomer cements during setting and its relation to pulp sensitivity. Journal of American Dental Association. 1986; 112: p. 654-657.
11. Ngo H, Mount G, Mc Intyre J, Tuisuva J, Von Doussa R. Chemical exchange between glass-ionomer restorations and residual carious dentine in permanent molars: An in vivo study. Journal of Dentistry. 2006; 34: p. 608-613.
12. Oong E, Griffin S, Kohn W, Gooch B, Caufiel P. The effect of dental sealants on bacteria levels in caries lesions: A review of the evidence. Journal of American Dental Association. 2008; 139: p. 271-278.
13. Prosser H, Jerome S, Wilson A. The Effect of Additives on the Setting Properties of a Glass-Ionomer Cement. Journal of Dental Research. 1982; 61: p. 195-1198.
14. Sidhu S, Watson T. Fiber reinforced GIC. Dental Update. 1995;: p. 429.
15. Hotz P, Mclean J, Sced I, Wilson A. The bond- ing of glass-ionomer cements to metal and tooth sub- strates. British Dental Journal. 1977; 142: p. 41-47.
16. Mclean J. Cermit. British Dental Journal. 1988; 164: p. 293.
18. Tjandrawinata R, Irie M, Suzuki K. Marginal gap formation and fluoride release of resin-modified glass-ionomer cement: Effect of silanized spherical silica filler addition. Dental Material Journals. 2004; 23: p. 305-313.
17. McLean J, Wilson A. Glass Ionomer cements. British Dental Journal. 2004; 196(9): p. 514-515.
19. Vermeersch G, Leloup G, Vreven J. Fluoride release from glass- ionomer cements, compomers and resin composites. Journal of Oral Rehabilitation. 2001; 28: p. 26-32.
20. SHOFU INC. 11 Kamitakamatsu-cho FHkK60J. www.shofu.co.jp. [Online].; 2001 [cited 2001. Available from: www.shofu.co.jp.

x

 

 

Authored by: admin

Leave a Reply

Your email address will not be published. Required fields are marked *