The short answer: it depends. Where is the cavity? How large is it? What do you mean by heal?
What is a cavity?
A cavity at its simplest is an area on a tooth where the demineralization-remineralization cycle has shifted toward demineralization due to high acidity. This happens most often because plaque ages and sits in one spot. The bacteria in the plaque produce more and more acid that ultimately removes mineral (calcium and phosphate, namely, which are the building blocks of hydroxyapatite) from the enamel. If the cycle remains shifted toward demineralization, the structure of the enamel eventually collapses and forms a hole or cavity.
Small cavities
Small (incipient) cavities can be “healed” via remineralization because they haven’t yet caved in and formed that hole. That’s what we mean when we answer “yes” to “can you heal cavities”? But is that area perfect as though a cavity never existed? No. The cavity process is stopped (arrested) and the mineral has been returned to the weakened area (remineralizatoin), so it is now smooth, strong, and hard, but there are often still subsurface microporosoties and discoloration present. These discolorations, if present in visible areas, can often be addressed by minimally invasive dentistry, such as resin infiltration (ICON).
Large cavities
As for larger cavities where the enamel (or dentin) has broken down and formed a hole, the answer becomes “no”. That full-thickness structure cannot be rebuilt. This is also true of acid erosion say for example, after pregnancy, if the mother experienced a lot of acid reflux and/or morning sickness, which resulted in enamel erosion. In these cases, a prosthesis may be required (crown or filling) to return the tooth to its original appearance and level of function. You can still stop the cavity’s progression (arrest) and make the area hard (remineralization), but enamel and dentin cannot be regrown. Not yet, anyway (come on, science!)
Factors At Play
Acidity
GENETICS: Bacteria are not the only source of acid. This is part of why genetics come into play as it relates to cavity risk. A person’s saliva may be more acidic if it has poorer buffering capacity. Some people may also have lower salivary flow naturally or as a consequence of medications they take (alcohol-based mouth rinses can be incredibly drying if used daily) or diseases (e.g., Sjogren’s, post cancer treatment, mouth breathing). Enamel and dentin can also be malformed and weaker (amelogenesis imperfecta, dentinogenesis imperfecta, dentin dysplasia, molar incisor hypoplasia, or moderate to severe fluorosis) as a result of genetics and/or environmental factors.
SYSTEMIC: Some of the strongest acid to meet our teeth and erode our enamel comes from the stomach. This is often in the form of acid reflux (gastroesophageal reflux disease) and vomiting (hello, pregnancy’s impact on teeth!). If someone suffers from reflux overnight where the stomach acid pools around the teeth, they can very quickly have weakened enamel that is more prone to decay and sensitivity. Any systemic causes should be addressed with your primary care doctor and addressed quickly to minimize negative dental impacts.
DIET: Dietary acid exposure sometimes sneaks up on people, especially parents. I cannot tell you how many families I have counseled whose children have high cavity rates despite good brushing habits, flossing daily, and avoiding sugar. In their quest for sugar-free alternatives, they end up selecting highly-flavored treats or drinks that utilize acids instead (malic, tartaric, citric, and phosphoric are the main offenders to watch for high up on the ingredients list). Crackers and chips are other sneaky culprits because they stay stuck to the teeth for long periods, and the processed starches are broken down by bacteria into acids.
The frequency of exposure, however, is more important than the amount. Many sugar-free candies and flavored waters result in increased acidity in the mouth, and if this exposure is frequent throughout the day, the teeth are never able to recover and switch to the remineralization phase of the cycle, thus placing them at higher risk for tooth decay. This same philosophy holds true for adults – so avoid sipping all day on acidic drinks (diet soda, la croix, flavored waters, coffee, energy drinks, etc.) or sucking on acidic candies for extended periods of time, even if they’re sugar-free.
Protective factors
One way to reduce acidity is to increase salivary flow, which acts as a buffer. Saliva is also the vehicle by which remineralization occurs (it carries the calcium and phosphate ions). This can be done by chewing xylitol gum or mints. Xylitol’s added benefit is that some research indicates a protective effect against cavities with daily use (3-5x a day) at a level of 6-10g for 6 months or more. Xylitol seems to make the prominent cavity-causing germ, streptococcus mutans, less virulent – i.e., less able to stick together in clumps and produce acid.
The other protective factor I won’t go without is fluoride. In low-dose topical applications, it is safe. If you’re at high risk for cavities or erosion, it may be the key to reducing acidity’s impact on your enamel. Fluoride works by incorporating itself into the hydroxyapatite structure as fluorapatite. This outer layer of fluorapatite makes the enamel more resistant to future acid breakdown because the pH at which fluorapatite demineralizes is 4.5 versus 5.5 of your natural hydroxyapatite. In the US, you can get fluoride via over-the-counter toothpaste (1100ppm) or mouth rinse (200ish ppm), prescription toothpaste (5000ppm), or tap water (0.7ppm).
Gum disease
People often follow up discussions about cavity risk by asking about gum disease. In a similar way, it’s an interaction between the body and microorganisms. You want to favor good microorganisms over bad ones. In the case of gum disease, the bad ones aren’t acid-producing so much as anaerobic (they love low oxygen environments like deep pockets of gum tissue and old plaque and tartar). Disrupting plaque biofilm is key and often involves deep cleaning treatments with your dentist to remove buildup and perhaps prescription products as aides. A hyper-responsive immune system is sometimes also at play and that angle is worth discussing with your dentist.
Helpful Products to Discuss With Your Dentist
Remineralization
Over-the-counter fluoride toothpaste, 1100ppm: Your standard run-of-the-mill fluoride paste is still a great tool for strengthening your enamel via fluorapatite incorporation (any brand and flavor you like).
Prescription toothpaste, 5000ppm: stronger for those at higher acidity exposure (JustRight, Prevident, Clinpro).
Nanohydroxyapatite: benchtop-level research plus years of use in Japan show it works as a remineralizing agent and can penetrate deeply into the tooth. The ideal concentration seems to be around 10-15%. Nanohydroxyapatite helps most with sensitivity. The mechanism of action is different than fluoride, so it shouldn’t be used as a replacement (CariFree CTx4 contains both fluoride (1100 or 5000) and nanoHA (15%) and is readily available in the US from a reputable company).
Tartar/Plaque control
Dimethyl isosorbide and sodium chlorite: These ingredients work to disrupt polypeptide bonds between tartar and the tooth, which over time can result in reduced buildup (TartarEnd toothpaste).
Tools: use whatever you will reach for consistently (daily) to disrupt the plaque biofilm along and underneath the gumline. Options include: string floss, floss picks, proxabrushes aka interdental brushes, or water flossers. Electric toothbrushes can be helpful but are not required; just be sure if you do purchase one that it has 30,000+ VPM or movements of the brush head and that you watch the video demonstration from the manufacturer about how to use it (typically there is no scrubbing in circles as with a manual toothbrush).
Bad Breath
Zinc: Disrupts VSCs (volatile sulfur compounds) produced by bad-breath-causing bacteria (in many rinses like Therabreath, Oxyfresh, and Closys).
Sodium chlorite: present in many of the mouthwashes above in antibacterial concentrations. At antimicrobial doses, I don’t think it should be used chronically so as not to disrupt the healthy organisms of the microbiome and should instead be used for a brief therapeutic period as instructed by your dentist. In TartarEnd toothpaste, the concentration is lower and not antibacterial but still results in fresher breath. It is unclear if it is shifting the microbiome to favor more aerobic bacteria or simply disrupting the VSCs from the bacteria that are unchanged.
Others: Similar to sodium chlorite at high concentrations, I think it is best to avoid daily use of any powerful antimicrobial unless specifically directed by your dentist so as not to disrupt the microbiome balance. Examples of powerful antimicrobials are: chlorhexidine, alcohol, essential oils, cetylpyridinium chloride (CPC). Even oil pulling daily was shown in a study to reduce the levels of beneficial planktonic (free floating in saliva) bacteria.
Bleeding gums/inflammation
See tartar/plaque control.
Frequent ulcers or burning with brushing
Products free of sodium lauryl sulfate (SLS) – menthol, eucalyptus, and/or cinnamon: e.g. hello, Biotene, Tanner’s Tasty Paste, some Sensodynes. These are all common ingredients in oral care products that people are sensitive to and can result in a spicy sensation with brushing and/or frequent mouth ulcers.
Systemic causes to investigate if frequent oral ulcers persist are: Crohn’s disease and celiac disease – ask your primary care physician.
Increase salivary flow
Chewing something sweet helps raise salivary flow. Try to avoid anything with sugar or that is flavored with acids. Some of my favorites are:
Basic Bites (arginine bicarbonate, calcium carbonate, and xylitol)
Xylitol gum (Pur, Epic, Spry, or Zellie’s)
Xylitol mints (Epic, Spry, Zellie’s, Smartmouth, Biotene)
Learn More
If you want more details and information on this topic of optimal mouth health, I created an entire course on the topic (half of with code: tiktok). I also share snippets of it on my socials (easiest to find on TikTok – yellow titles under tips/demos playlist). Still have questions? Find me on Instagram or Tiktok and ask away!
All products mentioned here can be found on my shop page organized by category. Most are affiliate links, and I appreciate your support should you choose to purchase them through my links.
