Dental caries, or tooth decay, are one of the most common issues seen in practices today. There are several different approaches for dealing with dental caries, each with its own benefits and risks.
Dental caries result from bacteria on teeth that produce acid, breaking down tooth enamel. The saliva in our mouth helps protect against this decay by removing food, dead cells and bacteria.
Patients who are on multiple medications or who are receiving radiation or chemotherapy may have lower saliva, making them susceptible to dental caries. There are more than 600 medications that diminish salivary flow. When a patient has less saliva in their mouth, they lose the bicarbonate, amylase, calcium, phosphate and fluoride that bathe the teeth and remineralize them. If you don’t have that remineralization process going on, it’s all subtractive.
It’s also common to see caries in patients with physical disabilities who may find brushing difficult. Additionally, patients who consume large amounts of sugar may have lower saliva and considerable tooth decay. The lack of saliva creates an acidic environment that is receptive to bacteria. When the pH falls below 5.5 for enamel, salivary buffers are overwhelmed and demineralization occurs.
The first step to tackling tooth decay is to confirm an accurate caries diagnosis, followed by a risk assessment and then conservative caries removal. Practitioners should treat the disease first, and reserve surgical approaches as a last resort. When this occurs, remove as little tooth structure as possible.
There are several different ways to remove caries:
Many of us were taught to do complete caries removal. However, that is not correct. There are problems that can arise from removing all the caries. A study in the Journal of Dental Research showed no difference in post-treatment sensitivity across different caries treatment types. But, several studies point to lower bond strengths in cases of full caries removal. Complete caries removal also exposes pulp most frequently and lowers the chances of success. Recent research on deep carious tissue management supports less invasive strategies.
Cochrane Oral Health Group is one group that assessed the most effective ways of treating and managing dental caries. They discovered that removal of all the decay has disadvantages, including pulpitis, post-operative main and weakened tooth structure. Stepwise and partial excavation also reduced exposures over complete removal.
The current evidence shows that in symptomless, vital, carious permanent teeth, stepwise and partial excavation has a clinical advantage over complete caries removal. With the case of stepwise, there is insufficient evidence to determine whether it’s necessary to reenter and excavate further. However, in studies that did not reenter, adverse effects were not reported.
A prominent research group in Germany also found that selective removal to soft dentin, where soft or leathery dentin is left in proximity to the pulp and sealed beneath a restoration, is recommended for deep lesions in adults. Alternatives include sealing lesions using resins for shallow, non-cavitated lesions, or stainless steel crowns.
Moreover, a study of the partial removal of carious dentine found that the success of partial carious dentin in a single session was 99% and the success of stepwise excavation was 86%. The study reported that retained carious dentin doesn’t interfere with pump vitality. Therefore, reopening to remove residual infected dentin isn’t necessary. One caveat is that the gingival area must be caries free. That margin has to be hard and clear.
One notable finding of recent studies relates to the isthmus width. The preparation size affects tooth strength and restoration longevity. Deeper preparations produced more fractures than a wider preparation, weakening the entire structure.
Treating deep carious lesions is a technical challenge. It’s best to conserve the tooth structure and preserve pump vitality, avoiding pulp exposure and improving the bond strength for adhesive restorations. With a deep carious lesion, sealing is an approach that reduces nutritional sources and decreases the type and number of bacteria. Although having sound margins is important, it’s best to avoid going to the center of the tooth and removing the caries. This approach will result in fewer exposures and less post-operative sensitivity.
These days, there are a number of ways to treat patients with a high amount of caries. This includes methods such as:
If you aren’t sure if you are going to restore the tooth, there are a variety of products that can be used to seal the lesion. The material is used to build up the tooth, and then observation occurs over a period of time. If after seven months it starts to break down, replacement is necessary. Sealing products include:
When it comes to tooth decay, dentistry has shifted toward minimal intervention. Years ago, the practice was to remove every bit of carious dentin. Now, study after study has shown that doing so exposes the pulp and lowers success rates. When working close to the pulp, a softer touch is best. This will reduce risk and improve outcomes. The endpoint of caries excavation is to remove infected caries dentin selectively while preserving affected carious dentin. Avoiding over-excavation preserves the remaining tooth structure and increases restoration longevity, as well as pupal vitality.
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