Diabetes and periodontal disease

By Richard H. Nagelberg, DDS

A recently published article in the Journal of the American Medical Association (JAMA. 2013;310(23):2523-2532) is sure to attract considerable attention. It is a multicenter study to determine if nonsurgical periodontal therapy reduces HbA1c levels, or stated another way, if blood sugar levels improve after periodontal treatment. The treatment group of 257 patients received SRP plus chlorhexidine rinses at baseline and maintenance at three and six months. The control group of 257 patients received no treatment for six months. At the conclusion of the study, the treatment group did not show glycemic control improvement, and the authors concluded that nonsurgical periodontal treatment should not be undertaken for the purpose of lowering levels of HbA1c.

This was a well-designed study conducted at five academic medical centers in the U.S. by highly reputable individuals. This was, to the authors' knowledge, the largest trial to date. It was noted that other studies with smaller numbers of subjects showed statistically significant improvements in glycemic control following periodontal treatment. The authors also discussed potential limitations of their study. Treatment did not include the use of systemic or topical antibiotics. Also noted were significant improvement in probing depths and clinical attachment levels following treatment; however, plaque and bleeding scores only improved modestly. Strengths of this study included the sample size and the diversity of the study subjects ethnically and geographically.

The conclusions reached in this study were well supported by the results. Potential explanations were also provided for the differences in the conclusions of the JAMA study and others that showed improvement in glycemic control, including differences in the number of subjects and greater control of changes to diabetes medications during the study. Another explanation advanced was the possibility that periodontal inflammation and infection do not influence glycemic control.

Some of the thoughts that come to mind from this and other studies are worth noting. Would a different measure of the clinical outcome yield different results? For example, did the number and species of bacteria shift from gram negative periodontal pathogens to gram positive favorable species after treatment was completed? Perhaps this is the explanation of the improvement in pocket depth and CAL but not for BOP and plaque scores. The authors did note that the persistence of the bleeding and plaque scores indicate that oral hygiene habits remain a challenge. With the benefit of hindsight, perhaps power toothbrushes and other biofilm control devices should have been provided. Eliminating the home-care variable is counterintuitive since it is the cornerstone of oral health. There are practitioners who address periodontal disease from a bacterial perspective. Shifts in the population of bacteria, rather than clinical parameters, are the target of therapy and therapeutic endpoints for these clinicians.

Similarly, the possibility that periodontal inflammation and infection do not influence glycemic control runs counter to the demonstrated elevation of blood sugar levels from infection and inflammation. Examples include ingrown toenails, bone fractures, and wounds of all types, among many others. Indeed, management of blood sugar levels for patients undergoing surgery is directly related to the outcome.

When a well-controlled diabetic individual suddenly experiences a spike in blood sugar levels, his or her physician will evaluate compliance with medication and lifestyle recommendations and look for an infection, as these are the most commonly encountered reasons for the spike in blood sugar.

It would be interesting and revealing to see if further studies that look at shifts in bacterial population as a measure of clinical success have the same or a different correlation with glycemic control. Similarly, inclusion of enhanced, meticulous daily biofilm control by the patients may impact the results. Gingival bleeding suggests an active disease process. Active disease is accompanied by elevated levels of inflammatory mediators. It is possible that the active disease and inflammatory mediators are impacting the conclusions.

This recent JAMA study is a significant piece of the ongoing research puzzle concerning the relationship between the mouth and the body and is highly credible given the meticulous manner in which it was conducted. As is the case with many studies, it will be interesting to see if further studies confirm these results or if different parameters provide different conclusions.

Richard Nagelberg, DDS, has practiced general dentistry in suburban Philadelphia for more than 30 years. He is a speaker, advisory board member, consultant, and key opinion leader for several dental companies and organizations, and he lectures on a variety of topics centered on understanding the impact dental professionals have beyond the oral cavity. Contact him at [email protected]