The failures of dental sealants: Weigh the pros and cons with dental patients

"Too often when a sealant fails, the decay has already reached the pulp resulting in extensive, costly restorative work. In hindsight, a patient who had a healthy, virgin tooth, now has a diseased one."

The significance of a dental sealant is to protect against and avert dental caries. Dental sealants are one of the most universally used safeguarding materials, as well as the most inadvertently misused product today. Sealants have a shelf-life of five to 10 years, but it is imperative to have them checked at each dental check-up visit to be sure they have not chipped or worn over time. The slightest chip or break can lead to leakage and trap food and bacteria underneath, which can cause decay.

Dental caries by definition “is an upset of the balance between loss and gain of minerals from a tooth surface.”¹The deficiency of nutrients from our teeth develop from the collection of bacteria housed within our mouths from daily consumption of food and drink that develop acids while saliva and fluoride provide minerals to our teeth. While this occurs, there is a counterbalance, and, if this is altered due to a continual intake of fermentable carbohydrates, poor oral hygiene and/or insufficient fluoride intake, the loss of minerals is significantly more than its gain which can fundamentally cause tooth decay.

Dental sealants are a preventive procedure, minimally invasive, that promotes early intervention to prevent carious lesions to form in the pit and fissures of the premolars and molar teeth. These pit and fissures are the biting surfaces of the teeth and are the most susceptible in harboring plaque and bacteria; causing carious lesions. The dental sealant seals these pit and fissures to prevent plaque and bacteria from collecting. Some indications and contraindications for placement are:

Indications for sealants

History of dental caries
Deep pit and fissure grooves
Poor oral hygiene
Enamel defects

Contraindications for sealants

Shallow pit and fissured grooves
Teeth that have been restored
Good oral hygiene
High caries risk patients

What happens when the dental sealant fails?

The most critical integral step to sealant placement and the reasoning for most sealant failures is the efficacy of placement. “80 percent of decay on young permanent teeth occurs in pit and fissure areas, and sealants have proven to be a very useful prevention tool.”¹

However, the success of the application doesn’t always go unhitched. Most sealants are placed on children, and a dry, clean environment is needed for the sealant to adhere and work efficiently. It is challenging to keep a child not only fixed and stock-still but the area in the mouth dry and salivary free. “It is for this reason that sealant success is now measured by the length of time a sealant remains on the tooth, rather than the decay experienced in sealed and unsealed teeth. The ability of a pit and fissure sealant to prevent dental caries is highly dependent on its ability to retain on the tooth surface.”¹

The use of acid-etch or adhesive systems before the application of dental sealants can increase retention. However, improper application is the leading cause of dental sealant failure. In a four-year clinical evaluation of sealants, “the sealant was fully retained on 50% of all paired permanent teeth at 48 months. Of the 689 pit regions that retained the sealant, 95% were rated as having severe loss of substance.”²

The leading cause of dental sealant failure is due improper placement allowing salivary contamination. This may be in part to clinician’s lack of experience, lack of patient cooperation and an inadequate amount of sealant material used. When a sealant fails, overtime bacteria leaks through and is harbored underneath releasing acids that eat away at the enamel. Under a sealant, the color changes to brown or dark brown and grows over time eventually assimilating into the pulp of the tooth causing pain as well as extensive treatment such as a possible pulpotomy. There are several factors that can help with sealant retention.

These include:

Isolation and prevention of saliva;
Operator experience and proper technique;
Properly preparing teeth: cleaning out bacteria and debris prior to sealant placement; and
Not applying sealants to partially erupted teeth.¹

Dental sealants arenot permanent and ordinarily last approximately five years. They act as physical barriers to the tooth surface and, if not placed correctly, can lead to an abolition of the enamel. After placement, normal wear may occur on the occlusal surface and may possibly chip off. It becomes formidable when a sealant wears or chips due to the ability to harbor bacteria underneath, causing decay.

Although sealants are preventive against decay, the failure rate is vastly high. Is it worth the risk? Too often when a sealant fails, the decay has already reached the pulp resulting in extensive, costly restorative work. In hindsight, a patient who had a healthy, virgin tooth, now has a diseased one. It is best to discuss the pros and cons of sealant placement with your patients and make the best treatment plan for them to obtain a healthy mouth.

References

Mehta, V. (2014). Five Key Criteria for Sealant Success.http://www.speareducation.com/spear-review/2014/03/five-key-criteria-for-sealant-success
Going RE, et al. "Four-year clinical evaluation of a pit and fissure sealant." The Journal of the American Dental Association 95.5 (1977): 972-981.
Dental Caries. Retrieved from: http://www.dictionary.com/browse/dental-caries
Simecek JW. (2005). Dental Sealant Longevity in a Cohort of Young U.S. Naval Personnel. J AM Dent Assoc. 2005;136(2):171-8.