What Is A Glass Ionomer Sealant?

As dentists continue to seal teeth to protect them from decay, new materials join the process. A glass ionomer sealant is one of the latest sealants dentists can use as an alternative to older, resin-based items. Often applied to newly emerging permanent molars – which are especially vulnerable to developing cavities – dental sealants coat the pits and fissures in teeth, preventing them from coming into contact with mouth bacteria and abrasive stomach acids.

Glass ionomer contains materials resin-based sealants don't use, and the application itself is also a bit different.

Glass Ionomer

Dr. Jan Stannard addresses three major ingredients in this type of sealant: liquid acid, glass powder and water. The acid reacts with the glass powder and, together with the water, form a substance that can stick to wet surfaces and allow water to pass through. Resin-based sealants must be applied to a dry surface, and repel water. Glass ionomer, on the other hand, naturally dissolves in the mouth's wet environment, and therefore does not offer permanent protection against decay.

Sealing Teeth

If a sealant doesn't fully stick to the tooth, the enamel beneath can become prone to decay. Sealing a tooth involves preparing it, applying the sealant and setting it with a curing light. The dentist may also allow it to harden by itself. Resin-based sealants require the tooth surface to be etched, rinsed and thoroughly dried to create a good seal, but isolating and drying a tooth in the moisture of the mouth can be challenging – especially if the tooth has not fully erupted from beneath the gum.

According to Rochelle G. Lindemeyer, DMD in Clinical Showcase, glass ionomer sealant is more likely to form a good seal when drying the tooth is more difficult, such as when the pits and fissures are very deep or when the tooth has yet to emerge from the gum.

Fluoride Release

Another advantage of glass ionomer sealant is that it releases fluoride, which strengthens tooth enamel. If the glass ionomer does not form a complete seal, or begins to leak over time, the fluoride ions it releases still provide some protection by mineralizing the tooth enamel.

Although the permeable nature of glass ionomer limits its protection against decay, Donald E. Antonson, DDS, MEd suggests in Oral Health Group that it does pose an advantage with respect to fluoride from toothpaste. Because this fluoride can pass through it more easily, it can strengthen the tooth's surface more effectively. Resin-based sealants do not allow fluoride through in this way.

Glass Ionomer Studies

Studies comparing glass ionomer with other sealants indicate similar benefits. Dr. Antonson refers to experiments that found glass ionomer penetrated deep pits and fissures better than other sealants, and even when the sealant was apparently missing decay, did not develop. This may be because sealant still existed in the deepest areas of the tooth.

Dr. Lindemeyer describes a study looking at the effects of glass ionomer on adjacent teeth that were not sealed. Compared to a conventional sealant that released fluoride, a resin-modified glass ionomer sealant appeared to offer better protection against decay in these adjacent teeth. Researchers speculated the glass ionomer acted like a fluoride reservoir, equivalent to brushing twice a day with fluoride toothpaste.

Depending on the needs of the patient, glass ionomer sealant may be the right choice for your child. Sealing the teeth is not the end-all answer to preventing tooth decay, but dental sealants can help during the years when children find it difficult to reach their emerging teeth to brush them properly. Even so, children who have had their teeth sealed should continue to brush twice a day with a fluoride toothpaste, such as Colgate® Kids 2 in 1 Watermelon Toothpaste, and to visit with their dentist regularly.