Glass Ionomer Cement Sealants by Dr. Jeanette MacLean

Glass Ionomer Cement Sealants 

Easier for clinicians, better for patients

by Dr. Jeanette MacLean

During my first decade of clinical practice, I thought sealant “success” meant retention of the bulk of material. Retention is a frequent metric mentioned in sealant studies, and my formal dental education led me to believe resin was the preferred sealant material because it does not wear.

Unfortunately, a lot of my misconceptions about glass ionomers were the result of a lack of training and limited experience with the material. I previously believed glass ionomer should be used only as a liner or crown cement because it would “wash out.”

In my private pediatric dental practice, the patients often stay from the time they are toddlers until they are in college—a perfect opportunity to see which materials and techniques truly stand the test of time. Over time, I noticed a recurring problem under my older patients’ leaking or chipped resin sealants: Decalcification or frank cavitation of the underlying enamel. This observation coincided with my adoption of minimal interventions for caries management and increased usage of glass ionomer restoratives.

I no longer judge a sealant based on retention of the sealant material, but rather its ability to prevent caries. Glass ionomer cement (GIC) fissure sealants are as effective as resin-based fissure sealants in the prevention of dental caries in the permanent dentition of children.1 However, several key physical properties of GIC make it a superior choice of material for sealants.

Key benefits

1. Hydrophilic. Glass ionomer sealants are hydrophilic and can be placed on a moist surface. GIC works better in a wet field, making it easier for clinicians to handle.2 GIC also has the unique ability to adhere to moist enamel and dentin without necessitating an intermediate agent.3 It frustrated me that sometimes I couldn’t achieve the isolation necessary for resin sealants because of a patient’s poor cooperation, dental anxiety, strong gag reflex or special needs—even more frustrating because these were often the patients whom sealants would benefit the most!

GIC can even be placed on partially erupted molars—a big no-no for resin. This is a huge advantage of GIC sealants, because partially erupted molars present a serious clinical challenge when they erupt into young mouths before the mandible has adequate arch length to accommodate them. Instead of taking a few weeks to erupt, the process may take months or even years, trapping food under the operculum in the meantime, and sometimes decaying the permanent molar before it has fully erupted. These isolation issues are no longer a concern now that I’ve switched to hydrophilic GIC sealants.

2. Fluoride release. GIC sealants release and recharge with fluoride, resulting in a caries prevention effect that is not retention-dependent. Loss of resin sealant retention, however, is associated with the risk of developing caries. Even when we think the bulk of a low-viscosity glass ionomer cement (LVGIC), such as Fuji Triage from GC America, has disappeared, small particles remain in the bottoms of fissures, acting as fluoride reservoirs that enhance nearby enamel remineralization. After 28 days, enamel adjacent to GIC contains 1,181.03 parts per million more fluoride than enamel adjacent to fluoride-containing resin.4

Don’t want LVGIC washout? Use a more wear-resistant high-viscosity glass ionomer cement (such as GC America’s Fuji IX) or a glass hybrid restorative (such as GC America’s Equia Forte).

3. Chemical bond. GIC sealants chemically bond to enamel via ionic crosslinking between the material and the tooth surface. Using a 20% polyacrylic acid cavity conditioner before applying a GIC sealant increases chelation between the enamel and the GI matrix, establishing a more stable bonding surface.5 Upon closer examination with scanning electron microscopy, you can see a chemical fusion zone established between the enamel and GIC, but it is difficult or impossible to see where one ends and the other begins.6

Chemical bonds are superior to resin tags because they are not prone to detachment or marginal breakdown. Over time, resin sealant can leak at the margins and develop caries underneath. This is a reason parents have used to decline having their children’s teeth sealed. I’ve heard stories like, “My dentist found a cavity under my old sealant that was so deep, I needed a root canal.”

Ironically, my one and only cavity was found during my early 20s by a dental school classmate under an old resin sealant on the distal lingual groove of my maxillary left second permanent molar. My sealant had leaked and chipped and was subsequently filled by my professor. (Thank you, Dr. Gardner Beale.) When playing the long game, glass ionomer is the sealant material of choice thanks to its chemical bond.

4. Biocompatible and antimicrobial. Glass ionomer is the most tooth-like dental material we have. Some parents have declined sealants for their kids based on concerns about plastic and bisphenol A (BPA). GIC sealant is BPA-free, contains zero resin monomers and has been proven safe and effective after decades of clinical use. GIC is antimicrobial, inhibits biofilm attachment and prevents damage from acid and bacteria on the tooth surface by creating an inhibition zone. Caries resistance from GIC at the cavosurface and adjacent smooth surface has been shown in both in vitro and in vivo studies.

The minerals released from GIC facilitate remineralization of enamel and prevention of lactobacilli and Streptococcus mutans bacterial growth on treated tooth surfaces as well as adjacent surfaces, reducing the risk of secondary caries.7 In essence, GIC sealants “share the love” with the sealed tooth and its neighbors.

5. Better for community health and school settings. Thanks to their lower technique sensitivity, good adherence, fluoride-releasing properties, and additive effect of being a sealant and fluoride provider for the prevention of occlusal caries, a 2018 systematic review and meta-analysis from the Journal of the American Dental Association identified GIC-based sealants as a good alternative to resin-based sealants, “specifically in community procedures when there is limited equipment, no chairside assistant for the dentist or dental hygienist, and a considerable number of children at high risk of developing caries.”

A six-year study of a comprehensive, multicomponent, school-based prevention program with 6,927 children in 33 U.S. public elementary schools published in 2021 demonstrated a 50% reduction of untreated caries. This program is an excellent example of the public health benefit of GIC sealants, which were used along with dental examinations, twice-yearly prophylaxis, glass ionomer interim therapeutic restorations, fluoride varnish, toothbrushes, fluoride toothpaste, oral hygiene instruction, and referral to community dentists as needed.8

Quick, effective, easy

I have seen dentists chat online about all the elaborate steps they take to place resin sealants—air abrasion, rubber dam, bonding agent, etc. This takes an insane amount of time, additional equipment and higher overhead, and still will not be tolerated by patients who are highly phobic, have a strong gag reflex or have special needs. More importantly, it does nothing to help the masses of children who lack access to dental care.

I think back to the ridiculous 45-minute separate appointments with nitrous oxide we used to schedule for routine resin sealants. On any given day, kids would come to their appointment only to refuse the nitrous nose, not tolerate the bite block, gag for cotton isolation or freak out at the sight of the etch syringe (mistaken for a “shot”), forcing us to abandon the mission. Some parents never even bothered to schedule the additional appointment for sealants— after all, it was hard enough to get them in for their six-month checkup. And then, of course, if I had a dollar for every patient chart that used to read “waiting on sealants due to maturity,” I’d have a whole lotta dollars. Talk about a waste of time and missed opportunity!

It’s almost comical how we used to unnecessarily overcomplicate things, simply because we just didn’t know any better. Maya Angelou once said, “Do the best you can do until you know better. Then when you know better, do better.” Now that I know the benefits of glass ionomer sealants, I can help more patients in a more efficient and effective manner, and I will never look back. I can now seal all four first permanent molars in less than five minutes, with one capsule of GIC, right at the patient’s recall exam. The kids are happy because it’s quick, simple and painless; the parents are grateful because they don’t need to schedule an additional appointment; the teeth benefit from GIC’s superior material properties; and our bottom line benefits from increased production. Everyone wins!

12 Steps to Success: Applying Glass Ionomer Cement (GIC) Sealants

1. Clean the tooth with plain pumice and rinse.

Glass Ionomer Cement Sealants

2. Apply 20% polyacrylic acid cavity conditioner (such as Cavity Conditioner, GC America) for 10 seconds with a microbrush.
Glass Ionomer Cement Sealants
Glass Ionomer Cement Sealants

3. Rinse off the conditioner with water.
Glass Ionomer Cement Sealants

4. Gently dry—but do not desiccate— the tooth to remove excess water.
Glass Ionomer Cement Sealants

5. Tap the GIC sealant capsule (here, Fuji Triage from GC America) on its side to loosen the glass particles.
Glass Ionomer Cement Sealants
Glass Ionomer Cement Sealants

6. Activate the capsule by firmly depressing the colored plunger on the bottom against the countertop.
Glass Ionomer Cement Sealants
Glass Ionomer Cement Sealants

7. Mix the capsule for 10 seconds in a capsule mixer.
Glass Ionomer Cement Sealants

8. Place the capsule into the applicator gun and click two or three times to move the material up toward the tip.
Glass Ionomer Cement Sealants

9. Immediately apply the material to the tooth’s pits and fissured grooves with the capsule applicator.
Glass Ionomer Cement Sealants

10. Quickly adapt the GIC to the tooth with a damp microbrush or cotton-tip applicator.
Glass Ionomer Cement Sealants

11. Let the material auto-cure for 2½ minutes.
Glass Ionomer Cement Sealants

12. Instruct the patient to eat only soft foods for 48 hours.

To download a free copy of Dr. Jeanette MacLean’s glass ionomer cement postoperative instructions form for patients, click here and under the Silver Diamine Fluoride pulldown menu, select “Resources for Dental Professionals.”

To watch a video tutorial for sealant application, click here.  


1. Seth, S. “Glass Ionomer Cement and Resin-Based Fissure Sealants Are Equally Effective in Caries Prevention.” J Am Dent Assoc. 2011 May; 142(5): 551–552.
2. Oba. A.A., Dülgergil, T., Sönmez, I.S., and Dogan, S. “Comparison of Caries Prevention With Glass Ionomer and Composite Resin Fissure Sealants.” J Formos Med Assoc. 2009 Nov; 108(11): 844–848.
3. Gurgan, S., Kutuk, Z.B., Yalcin, Cakir F., and Ergin, E. “A Randomized Controlled 10-Year Follow-Up of a Glass Ionomer Restorative Material in Class I and Class II Cavities.” J Dent. 2020 Mar; 94: 103–175.
4. Mickenautsch, S., Mount, G., and Yengopal, V. “Therapeutic Effect of Glass Ionomers: An Overview of Evidence.” Aust Dent J. 2011 Mar; 56(1): 10–15.
5. Alirezaei, M., Bagherian, A., and Sarraf Shirazi, A. “Glass Ionomer Cements As Fissure Sealing Materials: Yes or No?: A Systematic Review and Meta-Analysis.” J Am Dent Assoc. 2018 Jul; 149(7): 640–649.
6. Milicich, G. Journal of Microscopy, Vol. 217, Part 1, January 2005, 44–48.
7. Hicks, J., Garcia-Godoy, F., Donly, K., and Flaitz, C. “Fluoride-Releasing Restorative Materials and Secondary Caries.” Dent Clin North Am. 2002 Apr; 46(2): 247–276.
8. Starr, J.R., Ruff, R.R., Palmisano, J., Goodson, J.M., Bukhari, O.M., and Niederman, R. “Longitudinal Caries Prevalence in a Comprehensive, Multicomponent, School-Based Prevention Program.” J Am Dent Assoc. 2021 Mar; 152(3): 224–233.

Author Bio
Dr. Jeanette MacLean
Dr. Jeanette MacLean, a member of Dentaltown’s editorial advisory board, is a private practice pediatric dentist and the owner of Affiliated Children’s Dental Specialists in Glendale, Arizona. She is an internationally recognized expert and advocate of minimally invasive dentistry.

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