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What is WNL in dentistry?

Sept. 14, 2022
During virtually every dental examination, a notation of within normal limits (WNL) is made in the patient's health history if everything is consistent with good oral and overall health. But sometimes, it has another meaning.

Editor's note: Originally posted in 2017 and updated regularly.

During virtually every dental examination, there is a review or update of the patient’s health history as well as a clinical and radiographic examination. If everything is consistent with good oral and overall health, a notation of WNL is commonly made—an abbreviation for “within normal limits.” But does this standard visual examination truly mean that a thorough evaluation was made such that it can be accurately concluded that the patient does not have any pathology or conditions requiring intervention?

The use of technology and devices that extend our ability to see are also necessary to determine if a patient is truly WNL. Enhanced oral cancer screening devices, caries detection devices, CBCT imaging, and laboratory testing all enhance the extent to which we can see. Would we accurately conclude that a patient has no oral mucosal abnormalities without utilizing devices that see beyond the surface, or that there aren’t any noncavitated carious lesions without employing the use of enhanced caries detection devices?

The periodontium needs six-point probing to provide information regarding attachment loss. Spot probing periodontal screening and recording (PSR) will undoubtedly miss one or more areas that are periodontally involved. Recession needs to be recorded as well, since attachment loss is a more accurate measure of periodontal health than pocket depth alone. Comprehensive periodontal evaluation and charting are necessary to adequately determine if a patient’s periodontal health is WNL.

Its other meaning ...

There is, however, another less commonly known meaning to WNL—”we never looked”—which no one would ever document in the patient record. Looking goes way beyond visual observation and includes radiographs, scans, and lab work, among other tests.

Consider the scenario in which a patient has gingivitis for an extended period of time and develops rapid periodontal breakdown over a short period of time. If we identified the bacteria in the oral cavity by salivary testing prior to the breakdown, we might have noted highly pathogenic bacteria, which would have predicted the periodontal breakdown and perhaps given us the information needed to intervene in advance. But we never looked.

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When we diagnose a patient with periodontal disease and identify the causative bacteria, we are able to determine the likelihood of a successful outcome postoperatively. This powerful information gives us the opportunity to treatment plan nonresponding sites in advance, because we did look.

When we identify periodontal disease and treat without testing, we are treating pocket numbers, swelling, bleeding on probing, etc., which are merely the signs and symptoms of disease. But when we identify the specific bacteria responsible for the patient’s case of periodontal disease, we can then address the cause and reduce the likelihood of disease recurrence in the future. Without testing, we are simply guessing.

Is looking limited to identifying diseases and conditions that are currently present? Risk factors for a variety of pathologies need to be looked at as well, since disease prevention is more impactful than disease management. Identifying risk factors for periodontal disease—such as xerostomia, diabetes, smoking, and many others—is important to predict the likelihood of periodontal disease development and therapeutic success.

Human papillomavirus-derived (HPV) oral cancer is on the rise. Salivary testing for the presence of HPV has been available for years. Providing this testing for at-risk patients and those in target populations would ensure that they are truly within normal limits.

Looking is not limited to the boundaries of the oral cavity. A large body of research has concluded that specific periodontal pathogens are causative or involved in the development of atherosclerosis, cardiovascular disease, rheumatoid arthritis, and pregnancy complications, among other problems. Testing for the presence of these bacteria in the absence of periodontal disease should be provided for those patients with a health history or family history that indicates elevated risk. Patients with a family history of heart attack, stroke, diabetes, or rheumatoid arthritis should be considered for salivary testing to identify the presence or absence of bacteria, including Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum, and others.

It is worthwhile to periodically step back and examine the way we do things on a daily basis to determine if we are really looking and providing optimal care for our patients. Are they within normal limits, or did we never look?