Oral Health Sciences, Cystic Fibrosis and Antibiotics

Cystic fibrosis (CF) is a progressive disease caused by a genetic mutation that results in the build-up of thick mucus throughout the body. This affects multiple organs, with the lungs being the most impacted. The accumulation of mucus in the lungs creates the perfect environment for many strains of bacteria to thrive. Most CF patients are on long-term antibiotics to continually fight these infections. The life expectancy of individuals with CF is currently 44 years.

In dentistry, the long-held belief was that individuals with CF are at a lower risk for caries (cavities) across the board, largely due to chronic antibiotic use. This conclusion is now being reevaluated, with emerging research indicating a potential increase in caries prevalence in individuals with CF, particularly as the child enters adolescence, a time where there is a microbial, and, subsequently, antibiotic shift.

Reexamining the impact that antibiotics have on the oral health of individuals with CF is important, as is exploring the potential link between oral and pulmonary infections. In an era of antibiotic resistance, it is also important to recognize and address areas of improvement in antibiotic stewardship practices, both within dentistry and beyond.

I recently had the opportunity to speak with an expert on both matters: Dr. Donald L. Chi, DDS, PhD, of the University of Washington. As a board-certified pediatric dentist and health services researcher, Dr. Chi is a professor of Oral Health Sciences at the UW School of Dentistry, as well as a professor in the UW School of Public Health. He is Associate Chair for Research in the UW Department of Health Services, and has adjunct faculty appointments in the Department of Pediatrics (School of Medicine) and the Department of Pediatric Dentistry (School of Dentistry).

What is our current understanding of the relationship between cystic fibrosis, antibiotics and dental caries?

During my residency, we learned that individuals with CF are at a lower risk for dental caries - the reason for that being antibiotics. A few years ago, I wondered if the research had been updated. As I started to review the literature, it was incomplete. The conclusions were based on a small number of studies, the hypotheses weren’t very clear, and most studies had been done 20 or 30 years ago, many outside of the U.S. There had been no new research since I finished dental school and residency. As a professor, if I was ever in a position to teach dental students or residents about CF, I’d have to draw from the same incomplete literature that someone else drew from to teach me! I wanted to do something about it.

I won two small grants – one from the CF Foundation and a second from the School of Dentistry – to collect pilot data. Our study ended up being the largest CF oral health study done in the U.S. since 1980, and the largest, most comprehensive CF study done in the last 20 years. CF is quite rare, so if you want to do an adequately powered study you have to enroll across multiple institutions. What I learned from our study is that study participation rates are really high on CF. Individuals with CF are very willing to participate in research.

I think antibiotics are an important factor in understanding caries risk, but there is a lot we don’t know. Antibiotics are a potentially protective factor, but they could also be a risk factor depending on the type of antibiotic. They could also have moderating effects. So I think antibiotics and medications are really important in understanding risk factors. Untangling all of these complex relationships is critically important in coming up with interventions in preventing cavities and gum disease in individuals with CF.

It is hypothesized that tooth decay could increase the risk for lower respiratory colonization with pathogenic bacteria in individuals with CF. Is this relationship between oral and systemic infections frequently examined?

We are currently working on a National Institute of Health (NIH) grant for a multicenter study where we look not only at the risk factors for caries, such as antibiotics and behaviors like brushing and diet, but also at this link between the mouth and lungs. If you have an infection in the mouth, how does that affect what’s going on in your lungs? It’s a very simple hypothesis, but one that no one was asked. Of course, there will be complexities in data collection, for instance, distinguishing between biological specimens such as saliva and sputum. Our team is excited because we think we are going to learn a lot.

The American Dental Association (ADA) recently updated their antibiotic stewardship guidelines, indicating relatively few patient subpopulations for whom antibiotic prophylaxis would be necessary. When would you consider antibiotic prophylaxis appropriate? What has the policy change process been like?

Guidelines are guidelines. It takes a long time for guidelines to permeate into practice - there’s always a lag. One of the problems is that providers may not always have time to stay on top of the literature. But part of the problem is attributable to academics and policy makers. We develop a guideline, spend a lot of time and money publishing it, and then assume that end users will adopt it and change their practice, but that’s just not the way that clinical practice works. This isn’t unique to dentistry. Medicine is the same way - it just takes time for guidelines to be disseminated into practice. There’s a complex, non-linear pathway between evidence-based guidelines and what patients receive in terms of treatment. To complicate matters, I think many providers are put into a hard place when parents come in asking for antibiotics. They may even demand it. Physicians certainly see this, especially during cold and flu season when parents demand antibiotics.

For patients at risk for prosthetic joint infections, the American Dental Association (ADA) states that antibiotic prophylaxis should only be considered after consultation with their orthopedic surgeon. Does collaboration like this actually occur in practice?

The American Heart Association (AHA) is a really good resource to see how antibiotic prescribing guidelines have changed within dentistry. Before 2004 or 2005, antibiotics were considered for nearly every procedure where there was even the slightest potential for bacteria to be a problem. Definitely gum surgery, definitely extractions, even root canals - if there was any systemic health concern for the patient, standard antibiotics would be prescribed.

As I was starting residency, I remember a pretty significant shift in these guidelines that leaned toward being more conservative with antibiotic prescriptions for dental procedures.

That being said, for some patients, like those with particular types of heart conditions, dental bacteremia can be fatal. I think many providers, especially older providers who may have practiced when antibiotics were routinely used, have either had cases that have gone badly, or know of patients who have suffered as a result of post-dental treatment complications. Part of the tendency to overprescribe may be cautionary. I don’t think the antibiotic prescribing practices are necessarily malignant. It’s a combination of some providers not knowing any better and others thinking they’re doing the right thing.

References

Chi DL, Rosenfeld M, Mancl L, Chung WO, Presland RB, Sarvas E, Rothen M, Alkhateeb A, McNamara S, Genatossio A, Virella-Lowell I, Milla C, Scott J. Age-related heterogeneity in dental caries and associated risk factors in individuals with cystic fibrosis ages 6-20 years: A pilot study. J Cyst Fibros. 2018 Nov;17(6):747-759. doi: 10.1016/j.jcf.2018.06.009. Epub 2018 Jul 10. PMID: 30005828; PMCID: PMC6589399.

Cystic Fibrosis Foundation. (2020). Understanding changes in life expectancy. Retrieved from https://www.cff.org/Research/Researcher-Resources/Patient-Registry/Understanding-Changes-in-Life-Expectancy/

Department of Scientific Information, Evidence Synthesis & Translation Research, ADA Science & Research Institute, LLC. (2020, March 23). Antibiotic prophylaxis prior to dental procedures. Retrieved from https://www.ada.org/en/member-center/oral-health-topics/antibiotic-prophylaxis

Sarvas E, DDS, MSD, MPH, Chi DL, DDS, PhD, Kim A, DDS. Supporting oral health in patients with cystic fibrosis. Dimensions of Dental Hygiene. May 2016;14(05):45–48. Retrieved from https://dimensionsofdentalhygiene.com/article/supporting-oral-health-in-patients-with-cystic-fibrosis/