Strategies to Arrest Dental Caries

The COVID-19 pandemic has brought substantial change to our lives and to our profession. However, it also brought a silver lining to procedures that weren’t widely adopted before the pandemic. As many offices juggle ways to keep their doors open, less invasive procedures – with less aerosol production – have gained momentum. Here we will discuss two strategies to arrest carious lesions, 1) sealing occlusal non-cavitated lesions, and 2) arresting root caries with 5000ppm toothpaste. It is important to note that these strategies require the highest standard of care – as well as clear communication with your patients, not only of the rationale behind treatment choices but also the results they can expect. Let’s dig into the strategies.

1. Sealing non-cavitated carious lesion – wait, what?

Yes, you can use dental sealants to seal non-cavitated lesions. It may sound odd, considering that sealing over carious lesions is one of the main reasons dental professionals are hesitant to place sealants in the first place, but science says otherwise. For many years, dentists have been trained to either remove tooth decay right away or use the “wait and watch” approach when occlusal fissures or pits look suspicious. However, growing evidence has shown that you can decrease the chances of suspicious lesions advancing further by using a less invasive approach, such as dental sealants.

What do we mean in the clinic by a non-cavitated lesion?

These lesions are also known as early lesions, incipient lesions or white spot lesions. They present as demineralized areas with changes in color, glossiness or surface structure, without clinical signs of enamel cavitation. Lesions could be limited to enamel only or could extend to dentin. Clinically, this is difficult to distinguish, and x-rays might be needed. Usually lesions appear white, but they can also acquire some pigmentation, making them yellow or brown, or a combination thereof. Fortunately, at this stage, non-cavitated lesions can be arrested either by chemical means, such as with fluorides, or by placing a physical barrier like a sealant.

How do sealants arrest non-cavitated carious lesions?

Sealing over lesions is not new. In fact, there is clinical data going back to the late 1970s. The rationale for sealing a lesion is that a tight seal isolates the caries site and microbial biofilm from the environment. This finding came from observations of how cavitated lesions sealed with a restorative material arrested over time. Now, you might wonder what happens to the bacteria in that lesion – aren’t we leaving infection behind? Studies didn’t find much difference in the bacterial load between sealed and unsealed sites. Furthermore, some sealed lesions had lower levels of microbial load than unsealed lesions. In other words, bacteria didn’t proliferate under the sealants, as the bacteria died or went dormant due to nutrient starvation. In line with this, the most up to date guidelines by the American Dental Association (ADA) and the American Association of Pediatric Dentistry (AAPD) recommend the use of sealants to arrest non-cavitated lesions. The seal is the deal to avoid caries progression!

What factors should you consider when sealing non-cavitated carious lesions?

Let’s take a look at how to successfully translate this approach into clinical practice:

• Proper diagnosis: Of course, you need to have the proper candidate tooth (based on the description presented earlier) – but a less obvious recommendation for diagnosis is getting rid of that sharp explorer. Contrary to what many of us were taught in dental school, probing with a sharp explorer can hurt more than help, and you may accidentally cavitate a non-cavitated lesion. What is recommended now is good light illumination, air-drying and visual inspection. A ball-ended instrument can be used if needed.
• Depth of the lesion: Studies generally showed no differences in arrest rates in lesions located in the enamel only compared to lesions extending to the middle third of the dentin. The question then becomes: Is there a case where the lesion would be too deep to place a sealant even if it’s non-cavitated? To date, there is no consensus on a threshold. However, if a lesion presents little structure to withstand mastication and occlusal forces, then placing a sealant is not the solution of choice. On the other hand, shallow lesions are more likely to be successfully managed with sealants.
• Retention: Does the occlusal fissure offer poor retention? This is a critical question when deciding how to seal a lesion. Resin-based sealants have higher bond strength values to enamel compared with other materials and are the material of choice for those cases where the goal is long-term retention.
• Dry field: Yes, maintaining a dry field is a key aspect to success. Techniques vary from using a rubber dam to cotton rolls, but whatever your technique, the most important element is not to compromise the seal. In a situation where you have a partially erupted molar and moisture control is challenging, you may opt for a glass ionomer sealant, since resin-based sealants are more sensitive to contamination. GI sealants are more moisture tolerant but don’t offer the same retention rates as resin-based sealants – and the evidence supporting their long-term performance for arresting lesions is limited.
• Monitoring: Regular visits to the dentist are required to evaluate the state of the sealant. If a sealant is dislodged partially or completely, the seal of that lesion is lost. Food debris, saliva and microbes can regain access to the site and reactivate the caries process. Routine visits can help detect an early failure, so you can plan to repair or replace the sealant. Explaining the importance of routine maintenance to the patient or guardian ahead of the procedure is critical for adherence to checkups.

Why aren’t we using sealants more?

There are several factors that contribute to the low level of sealant utilization in dental practices. The first is a lack of awareness of the growing body of evidence supporting their indication for caries arrest, which shows that sealants are effective at both preventing and arresting non-cavitated caries lesions in primary and permanent molars. Insurance in the U.S. is another important limiting factor for widespread adoption and treatment acceptance. As clinicians, we need to explain the long-term benefits of doing less invasive procedures and how they play into keeping our patients healthy. If a lesion progresses due to lack of intervention, that tooth will need a more invasive restoration – which comes with a higher cost, both economically and biologically.

2. Use of 5000ppm fluoride toothpaste to arrest root caries

This is an underutilized weapon that has become more relevant during the pandemic. According to the 2018 non-restorative clinical guidelines by the ADA, the use of a 5000ppm toothpaste is the recommended approach to arrest root caries, whether they are non-cavitated or cavitated. Armed with this information, you have a convenient way to help keep your patients’ caries under control and avoid progression. Several countries, including the U.S., are experiencing a change in demographics with a growing segment of the elderly population that is retaining teeth longer than previous generations. This has also been accompanied by a higher prevalence of root caries, most likely due to a combination of increased gingival recession and dry mouth. This is an ugly mixture of factors that facilitate rapid onset and progression of root caries if left without proper intervention.

What is the evidence behind the use of 5000ppm toothpaste?

Recently, the ADA appraised evidence from clinical trials on root caries arrest using a variety of interventions. The expert panel suggested that clinicians prioritize the daily use of 5,000ppm fluoride (1.1% NaF) toothpaste or gel over other interventions. Since it is more difficult to clinically distinguish if root caries is cavitated, they recommend the approach to be taken in both cases. Read the full report here.

What are the key factors for arresting root carious lesions?

The amount of evidence to date is still limited but several factors can be mentioned:

• Diagnosis and lesion location: Making a proper diagnosis almost goes without saying, but sometimes the location of these lesions can make it difficult to assess depth. X-rays along with pulpal health assessment may be necessary. Lesions in locations that allow effective cleaning by the patient will benefit from the combination of proper toothbrushing technique and high fluoride toothpaste. On the other hand, lesions that are difficult to access with oral hygiene techniques may need different interventions or combination therapies.
• Patient adherence to treatment: Of course, this is not new for at-home product usage. Patient compliance, in this case, will involve filling the prescriptions as needed and, more importantly, daily use at home following the instructions. Constant exposure to a high concentration of fluoride is critical to remineralization and caries arrest.
• Ability to perform oral hygiene: Older adults may have problems conducting proper oral hygiene independently and might need to rely on a family member, staff member or nurse (if living in a nursing home or assisted living facility) for help. If this is the case, this approach may not be the right one, as it depends on the patient’s ability to practice oral hygiene.
• Monitoring: The clinical arrest of root caries is usually assessed based on several parameters. Tooth texture on gentle probing is one of the main criteria and is usually done in conjunction with assessment of surface appearance (color and continuity) and degree of plaque accumulation. A lesion that has arrested should become harder over time, may turn a darker color, and should feel smooth upon probing. If the lesion has not become arrested, it is important to decide on another intervention to stop the progression.

Going beyond arresting

In summary, the use of sealants and 5000ppm toothpaste for caries arrest allows for the implementation of minimally invasive strategies to keep our patients healthy. Keep in mind that for any therapy to succeed, educating patients on their oral health condition and treatment is critical, and must go hand in hand with good care at home. During this pandemic, our communication should, at a minimum, include recommendations for brushing twice a day with fluoride toothpaste and interdental cleaning at least once a day, as well as eating a healthy diet that limits sugary snacks between meals. This level of communication extends our services and oral health support beyond the walls of our clinics. These efforts, along with less invasive strategies, will help us move forward through the pandemic and into future – towards better oral health for all.