Regardless of the material used, the tooth must be properly cleaned before placing anything there. The best way to do this is to use an air polisher. And the best air polishing powder is one that can remove necrotic enamel and create damaged enamel, and that is a bioactive glass (Sylc Velopex).
The highest risk population in low income clinics have hygienists under the worst possible conditions placing the most technically sensitive resin sealants without properly preparing the tooth. The prophetic brush is not the right tool for this job. Insufficient suction is almost a given. Then apply the recommended adhesive and cure.
Glass ionomer is a bit more forgiving in tooth preparation. There is no engraving step. The tooth must be clean, but etching and bonding is not necessary. The tooth must be wet. I don’t swim in saliva or water, just wet. The material is self-hardening, this means that there is no light. Now you are wondering what is the downside. You will need to replace the curing light with a sander. Note to the purchasing department: a sander is much less expensive than a curing lamp.
Finally, what about that color? One of the very little known ingredients in enamel is strontium, and strontium is what gives pink glass ionomer sealer its color. “There is a negative correlation between strontium and the occurrence of dental caries” is the research paper that talks about “teeth with a good concentration of strontium have less caries.”
The pink color is also an indicator of its presence. By noticing with the naked eye that a tooth no longer has a pink fissure, you can be sure that there is still some coverage and you can safely place a new glass ionomer sealant just over the top of the invisible material and it will fuse again. The strontium in glass ionomer sealants is also what allows the immature enamel to mature under the sealant. Curing is not possible under a resin sealant.
We used to think it was okay to seal the initial decay with a resin sealant. We used to say that the bacteria would die, because there would be no oxygen and no food. Our understanding of a biofilm has changed over the past decade. We often see research papers talking about homogeneous biofilms. In fact, a homogeneous group of bacteria, even with a layer of mud, is a large colony. It is true that you can cut off a colony from oxygen and food. The definition of biofilm is the heterogeneous combination of bacteria that acts as an organism.
The way we now understand a biofilm, some bacteria live in someone else’s waste, and anaerobic bacteria live in different neighborhoods than aerobic bacteria, and that some bacteria produce oxygen. Thus the ecosystem can be inhabited by cariogenic bacteria living under the resin canopy. So don’t, unless you’re using a glass ionomer.
Glass ionomers are so forgiving of poor working conditions that an entire protocol was developed in the 1990s called atraumatic restorative therapy (ART). The glass ionomer is essentially pulped in lesions that extend almost into the pulp chamber. Larger lesions were minimally prepared with hand tools. The retention of these fillings and sealants has been monitored for six years and the progression of decay captured.
What does a recent meta-analysis show? Let’s try to ignore the fact that out of over 2,800 papers on sealants collected since 1973, only 24 were eligible for analysis. Ten of the studies looked at glass ionomers, and in every important measure, the glass ionomer sealant outperformed the resin repeat:
- 29% lower risk of new caries lesions in those who received glass ionomer sealants versus resin sealants at the two- to three-year follow-up.
- At the four- to seven-year follow-up, the risk of new caries lesions was reduced by 63% compared to participants with a resin sealant.
The authors also examined resin-modified glass ionomers, which have the same inherent placement problems as traditional resin sealants. There are some products in this category that are self-curing. In the discussion section of the meta-analysis, the authors state: “In making clinical decisions, we suggest that clinicians consider the possibility that their patients may experience a lack of retention inherent to the sealant as well as their ability to isolate and maintain a dry field at placement.”
Glass ionomers are one of the magic products we have in dentistry. It is extremely forgiving and not sensitive to moisture. Let’s cross our fingers that more studies take a look at glassionomers. Currently, two companies offer glass ionomer sealants. Riva is offered by SDI. GC America offers Triage.
The pink color is part of the glass ionomer story so the clinician can see it is there and not confuse it with a prosthetic use of the material to replace lost enamel. If the pink is no longer visible to the naked eye, you can apply a second layer over the invisible layer to reduce the scares. The goal of sealants is to reduce the chance of tooth decay in the most vulnerable part of the tooth. Anything less than a glass ionomer can put the tooth at risk.
Shirley Gutkowski, RDH, BSDH, is a practicing dental hygienist specializing in orofacial musculofunctional therapy. Her practice, Primal Air, LLC, is located in Sun Prairie, Wisconsin. Ms. Gutkowski is also the host of Cross Link Radio, a podcast with timely information integrating oral and systemic health.
