The Evidence Supporting Fluoride Varnish

Alex Collaborator 9 minutes read

dental caries

Dental caries (tooth decay) is a common health problem across the world. The condition affects both adults and children. Tooth decay arises as a result of bacteria in dental plaque that produce acids that wear out the enamel. They break down sugar or bacteria from the food consumed to produce acid responsible for damaging teeth. Tooth decay causes progressive damage to the crowns and enamel if it goes untreated. Caries is a manageable and preventable condition. Fluoride in products such as fluoride varnish, toothpaste, and mouth rinses is one of the best remedies for the disease. It prevents tooth decay in several ways which include:

  •     Supplying minerals that strengthen the teeth. Minerals such as calcium and phosphate are vital for tooth remineralization. Saliva and dental plaque act as fluoride holders to boost the remineralization process.
  •     Fluoride minimizes the chances of experiencing acid action on the teeth once incorporated into the enamel.
  •     Fluoride ions stop bacteria from taking over the teeth, preventing acid action and reducing demineralization. Using it and other dental cleaning products like prophy paste prevents bacteria buildup.

Fluoride occurs naturally in drinking water and saliva. Findings from research conducted on water samples used by a population living in the US-Mexico border showed that the amount of fluoride in the bottled water they consume is 0.4 mg/L. This is slightly lower than the amount in tap water which averaged 0.49 mg/dL. People from regions with water that has minimum levels of the mineral should look for other forms of fluoride supplementation.

Salivary fluoride levels do vary depending on factors like fluoride in water used by an individual, personal diet and fluoride usage. The average concentration of the mineral in the saliva is between 0.01 to 0.10 mg/L. It is capable of enhancing remineralization because of its qualities. Other fluoride sources with minimal concentration include dental care products such as toothpaste and mouth rinses. Fluoride varnish is the most popular high concentration source of the mineral.


Qualities of Fluoride Varnish

This fluoride product is meant for professional application in a wonderful dental clinic by a dentist or dental hygienist because of its mineral concentration. The average concentration of fluoride in this varnish is 9000 ppm. Fluoride varnish can be applied easily without the need for oral suctioning. This makes it ideal for young children, the physically disabled and individuals who experience pharyngeal reflex.  It is more effective when applied to dried teeth. The teeth can be dried using a cotton gauze before topical application.

Fluoride varnish (Center, OHRC 2015) boosts fluoride concentration of enamel and crowns, improving the uptake of the mineral when experiencing demineralization. It solidifies on the tooth surface once it comes into contact with saliva. This makes the mineral stay on the teeth for up to a week after rinsing. Fluoride varnish is more effective compared to other high concentration fluoride products like gels or foams which hold the mineral on the teeth for about 15 to 20 minutes.

The American Dental Association, ADA recommends an end to the use of foam which is less effective compared to gel or varnish. Some fluoride varnish products leave yellow stains on the teeth. Fluoride deposits in the tooth surface are higher in demineralized teeth compared to a healthy tooth surface. This varnish highly benefits people who are at moderate or high risk of tooth decay.

Evidence-Based Findings Supporting Fluoride Varnish

fluoride varnish application

Fluoride varnish is ideal for the prevention or management of caries. Its effectiveness in protecting or managing caries is highly based on the evidence tabled by ADA and Centers for Disease Control and Prevention, CDC, the US health protection agency. The quality of evidence obtained by ADA in 2013 on the success of fluoride varnish in preventing caries in young children is high, and they continue to recommend its regular application.

In a random clinical test performed in Canada, about 1,000 young children with high levels of tooth decay were offered caregiver counseling, and fluoride varnish was applied to their teeth three times a year for two consecutive years. The test turned out positive recording a reduction of tooth decay by 18% to 25%


There are several recommendations for fluoride varnish use. The strength of recommendation varies depending on the best evidence available. Evidence provided may vary from strong to weak and can also differ from one to another. Categories (astdd 2013) of evidence in this case include:

  •     Strong- This type of evidence highly supports fluoride varnish intervention.
  •     In Favor- The evidence favors offering fluoride varnish treatment.
  •     Weak- This type of evidence proposes applying this intervention after other alternatives have been factored.
  •     Expert Opinion For- Here, the evidence is completely lacking, with low positive assurance. This recommendation is guided by expert opinion.
  •     Expert Opinion Against- There is no evidence at all, zero positive assurance, expert opinion recommends that this intervention should not be implemented.
  •     Against- Evidence is for the implementation of fluoride varnish application or halting the less effective procedures.

One study (Physicians 2016) reviewed whether fluoride varnish is safe in averting dental caries in children or adolescents. 22 trials composed of 12,455 patients who fall in the age bracket of 1 to 16 were reviewed. Fluoride varnish was administered to patients 2 to 4 times in a year vs other treatments like gel or nothing at all with a study period of between 1 to 5 years. The final result gauged the number of decayed-missing-filled (DMF) permanent tooth surfaces. Both the control and treatment groups had their DMF evaluated and later used to calculate the fraction of the prevented percentage. Researchers also looked for different things that could influence the effectiveness of fluoride varnishes such as the severity of the decay condition, fluoride varnish concentration, and pre-application procedures.

child at the dentist

The evidence-based answer for this finding was fluoride varnishes are safe in the prevention of tooth decay in children and adolescents. There is minimal information on the severe effects or eligibility for the treatment. Family doctors should include fluoride varnish treatments in preventive dental care treatments for children. This evidence was seen to be of average quality because most of the studies indicated showed some level of bias in the bias assessment. Zero severe effects were also recorded.

The American Dental Association also offered clinical recommendations in 2013 for the use of topical fluorides in caries prevention among patients who are at high risk of developing the condition. This was based on the evidence they have. Evidence strength will be according to the categories given above. The reviews and recommendations were as follows:

Age categories tested include children younger than 6 years, 6 to 18 years, over 18 years and adults who had fluoride varnish applied professionally. They all used 2.26% (5.0% NaF) of fluoride varnish every three to six months. The evidence category was in favor of children younger than six years and those between 6 to 18 years. Evidence strength for those above 18 years and senior adults fell under the category expert opinion. Some children above six years to the adult group were also given a home prescription 0.09% fluoride mouth rinse to be used every week. The level of evidence was the same as those who underwent professional fluoride varnish applications.

The other review from ADA's 2013 recommendation publishing involved the use of APF fluoride gel. This was performed on age groups 6 to 18 years, older than 18 and adults. It involved the professional application of 1.23% APF fluoride gel for four minutes every three to six months. The category of the evidence turned out in favor of those in the 6 to 18 years age bracket and expert opinion, for those older than 18 years and adults. Just like fluoride varnish, a particular group in the same age categories had to do personal or home applications. They all applied 0.5% of fluoride gel or paste twice a day. The evidence level was expert opinion for in all the age brackets that did the personal application. 

Fluoride foams, rinses or gels are not highly recommended like varnish because of their high toxicity levels (Group 2016). They pose several risks to the body when swallowed or absorbed through openings such as mouth wounds or bleeding gums. They are also not effective because of their contact on the tooth surface. Gels and foams take at least four minutes on the tooth surface. This makes the treatment challenging in toddlers and the elderly. Fluoride varnish is the best because the mineral stays in the teeth for long to offer the desired treatment. Product selection is also vital in fluoride treatment.

Fluoride Varnish Cover

Dentists or dental hygienists are advised to examine their clients first before applying the product. This is vital in identifying the correct concentration. Certain varnishes can be used on moist teeth while others are applied to dry teeth. The product is more effective when applied to dry teeth. Post-application practices also play an essential role in bringing out quality results from the use of the product. Dentists should advise their patients on the right post-application procedures such as avoiding certain drinks or foods to guarantee quality results. Fluoride varnish is the best high-concentration fluoride product that should be used on children, teenagers, and adults.



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