Oral Health Group
Feature

New Glass Ionomer System and Application in Children

August 1, 2011
by Carla Cohn, DMD


INTRODUCTION
Children are an integral part of every family dentistry practice. There is no doubt that children can be a tremendous practice builder, just as there is no doubt that children can, on occasion, be a tremendous challenge.

There are times in all of our practices when we are challenged with a pre-cooperative or an uncooperative child. In these instances it is often difficult to have a “five star experience” and place “five star dentistry” at the same time. Our job as dental professionals treating children is twofold, we must place quality work for our patients and we must be masters at managing our patient’s experience. We must be able to work with speed and accuracy. This can only be possible if we have materials at hand that are easy to handle and give dependable results. One such material is glass ionomer.

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Glass Ionomer Use in Children
Glass ionomer has been used as a dental material since its introduction in the 1970s.1 At its introduction as a restorative material there were some limitations to the material. The handling characteristics were less than ideal, it tended to wash out of the restoration over time, and the material was not highly polishable. Since their introduction, glass ionomers have evolved and have been improved immensely. Today’s glass ionomers are easier to handle, have better wear resistance, and have better esthetics than the original glass ionomers.2-4

Glass ionomers have many advantages as a restorative material. These include, but are not limited to: the ability to bond chemically to dentin and enamel, biocompatibility, favorable thermal expansion, decreased moisture sensitivity and the ability to act as a fluoride release and then as a reservoir. As a result of these qualities, glass ionomer is ideal for the pre-cooperative or uncooperative child as well as the “high caries risk” child.

The ability to bond chemically in a moist environment is critical in some of the techniques employed in pediatric dentistry. Moisture control in a pre-cooperative or uncooperative child is often a challenge. It can be difficult at best to maintain a dry field. Composite materials require a dry field in order to be successful in their bond and set. Glass ionomers allow some moisture in the field of operation and still form a reliable bond and therefore a successful restoration.

Atraumatic restorative techniques (ART), or intermediate restorative techniques are techniques used in very young, uncooperative, or otherwise compromised patients. They are useful in those patients in which traditional preparation of the affected tooth is not possible. In these techniques, hand instrumentation or slow speed rotary instruments are used to remove decay. Glass ionomer is used as the restorative material of choice. A preparation with a solid periphery, no pulpal exposure and a complete seal is imperative for clinical success. There is little evidence that affected dentin must be removed prior to sealing a tooth.5 It is, in fact, acceptable to leave affected dentin behind, provided that it is sealed properly. Dentin has the ability to remineralize when in contact with glass ionomer.6 In a recent study, it has been shown that there is a decrease in the bacteria in a lesion restored with a glass ionomer material thereby improving the healing process of the tooth.7 Given these properties, glass ionomers are often used as dentin replacement materials.8-10

The fluoride release of glass ionomer makes it an ideal choice for those patients at “moderate to high risk” for dental caries.

Glass ionomers display a cariostatic quality in their ability to act as a reservoir for fluoride. Not only are glass ionomers a source of fluoride when they are initially placed, but in addition to this quality, glass ionomers are absorbent and act as a sponge in the uptake and subsequent release of fluoride. This “recharge” of fluoride can occur from exposure of the glass ionomer restoration to fluoridated dentifrice and mouth rinses, and professionally applied fluoride treatments. Fluoride has long been recognized as a powerful tool in the battle against caries. It is effective as an antibacterial, in remineralizing enamel and in creating more acid resistant enamel by the formation of fluorapatite.

Comparison of Restorative Options for Primary Teeth
In pediatric dentistry our choices are routinely limited to the following: amalgam, composite resin, compomer, glass ionomer and stainless steel crowns.11

A brief comparison of these materials is warranted. Amalgam has many excellent properties as a restorative material, however the demand for tooth colored restorations is very high. As well, there is current controversy over mercury content in amalgam materials.

Composite resin offers a strong and esthetic alternative. However it is technique sensitive, and a highly moisture sensitive material. In ideal clinical situations, composite resin restorations may well be the material of choice. However in those situations in which moisture control is not ideal, resin composites fail miserably. By comparison, glass ionomer is considerably less moisture sensitive and therefore a good choice in situations where moisture control is not perfect.12 Currently, glass- ionomer is the only restorative material that is water-based and like silicate has an anti- caries effect.13,14

Stainless steel crowns are a very reliable restoration, providing a dependable choice, however they are not esthetically pleasing and require extensive tooth preparation. In a child who is less than cooperative for dental treatment we must look to alternatives that will allow us to restore a carious lesion in a less invasive manner. That alternative may well be a glass ionomer restoration.

Indications for Glass Ionomer
The American Academy of Pediatric Dentistry15, in the following instances, indicates the use of glass ionomer as a restorative material:

1. class I, II, III, and V restorations in primary teeth,

2. class III and V restorations in a high risk16, permanent tooth or in a permanent tooth in which isolation is not possible,

3. as a caries control material in any of the following instances: high risk patients restoration repair, interim therapeutic restorations, or alternative or atraumatic restorative techniques.

As well, the use of glass ionomer in a “sandwich” technique has long been recognized for its benefits as a material that can give a complete seal, and a reliable bond. The restoration is esthetically pleasing due to an overlay of a composite resin material. Thus we can have the best qualities and strengths of both materials.

The Newest Glass Ionomer Technology
EquiaTM, is a new glass ionomer restorative system, recently introduced by GC America. It is a combination of a self-adhesive highly filled glass ionomer (Fuji IX GP Extra) and a self- adhesive filled resin surface sealant (G Coat Plus).
The three following components of this system warrant some discussion.

Self-adhesive: The Equia system allows for use with or without a cavity conditioner. Use as a self adhesive without the cavity conditioner allows for the establishment of a chemical bond. Glass ionomer is distinctive in its ability to form a stable ionic bond as it sets with an “acid / base” reaction between the material and tooth structure.17 A reliable bond and seal between tooth structure and restorative material is subsequently formed. Glass ionomer has this ability to “provide a long-lasting seal under the most challenging clinical circumstances.18 The conditioner (GC Cavity Conditioner) can be used when circumstances warrant. The conditioner is 10% polyacrylic acid which cleanses and serves to enhance the bond strength through mechanical retention.

Filled Glass Ionomer: Fuji IX GP Extra is a highly filled glass ionomer. The esthetics of the material has been improved. Its high vis
cosity allows for better handling and a decrease in wear resistance. The material is a fast setting compound that is packable. Set time is just 2 minutes and 30 seconds.

Sealant: The sealant (G Coat Plus) has multiple advantages. It fills in voids of the restoration and reduces the surface irregularity. Sealant application allows for the glass ionomer to chemically cure without desiccation, and allows for improved marginal integrity.19 Application of the sealant will act to reduce wear rate of the restoration.20 Clinical performance, in short-term studies, has been shown to be as good as micro-filled composite restorations.21

TECHNIQUE
Patient QR, age 3 years 3 months, presented with occlusal and lingual decay on his primary maxillary second molar.
Patient is high risk for caries with a DMFT of 6. Equia was deemed the material of choice due to patient age and caries risk.
Teeth were isolated with a rubber dam. Preparations were completed with a slow speed rotary instrument and decay was excavated.

Cavity conditioner was placed over the entire preparation for 10 seconds and rinsed completely.

Glass ionomer Fuji IX GP Extra was injected into the base of both of the preparations. The tip was removed slowly in order to not incorporate any voids in the restoration.

The restoration was finished, with a large (#8) round bur, slow speed hand piece. G Coat was placed over the entire restoration and margins.

TECHNIQUE
Patient DM, age 4 years 2 months, presented with a carious lesion on the mesial aspect of his primary central incisor. DM is what could be called pre-cooperative. His DMFT was 8, and he is a high-risk patient for developing dental caries. He is a very active little boy who could sit for only a limited time for treatment. He had a previously placed restoration that had failed due to a combination of inadequate bond and the flexure of the tooth. Treatment plan was to place a self-adhesive glass ionomer (Equia GC America) in order to take advantage of the chemical bond of the material as well as the fast working time.

As well as speed being a factor, DM became frightened by the sound of the high-speed suction. As a result, washing and drying the tooth became a challenge. To maximize the DM’s cooperation it was determined that the additional step of using the cavity conditioner would likely decrease cooperation and therefore success. The chemical bond of the glass ionomer would have to suffice.

The tooth was isolated with cotton rolls and was prepared minimally with a slow speed rotary instrument. A mylar strip was placed interproximally and glass ionomer was injected into the preparation. The material was condensed with a flat instrument. Once set, it was polished with a large (#8) round bur, slow speed, and Enhance (Dentsply) finishing cups. An interproximal strip was used to finish the final contour. G-Coat Plus (GC America) was applied to the surface and margins of the restoration.

CONCLUSION
Many times, the children are sent to the dentist first and if they have what is deemed a “good experience” the rest of the family joins the practice as patients as well.

When given the privilege of having children as our patients, we are given the responsibility for that child as well of creating their attitudes towards dentistry as a whole. We have the power to shape that child’s thoughts on what a visit to the dentist is all about.

When treating children the experience is equally as important as quality of the final restorations. We strive to balance our patients experience with the high quality of dentistry that we all aim to achieve.

Materials continue to evolve and improve to make our goals achievable.OH

Dr. Cohn graduated from the Faculty of Dentistry, University of Manitoba in 1991. She completed a post-graduate internship in Children’s Dentistry at Health Science Centre Children’s Hospital in Winnipeg, MB. In addition to private practice, Dr. Cohn has surgical privileges at Western Surgery Centre, a private surgical clinic. She is a clinical instructor, part-time, in the department of Preventive Sciences at the University of Manitoba. Dr. Cohn has lectures on risk assessment, prevention, behaviour management and restorative treatment options.

Oral Health welcomes this original article.

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