by Patti DiGangi, RDH, BS, and Shirley Gutkowski, RDH, BS
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Today, science and new technologies are proliferating and changing the way we practice. Dentistry is a science and an art that must employ the finest tools available — not just the finest in science and technology, but the finest in the knowledge, skills, and character of the dental professional. There is no "one-size-fits-all" treatment plan guaranteed to work for every person in every case. A gold standard is a definitive diagnostic test or benchmark. The gold standard for detecting caries infection is changing.
English is the most widely spoken language in the history of our planet. When we take the time to step back, we find common usage can blur the correct meaning of words. CPR class participants interchange the terms heart attack and cardiac arrest, but they are not interchangeable terms. Though both need care, CPR is needed for cardiac arrest, but not for a heart attack.
Cardiovascular disease (CVD) is the leading cause of death and serious illness in the United States. In 1948, the Framingham Heart Study embarked on an ambitious project that lasted more than 50 years. This study changed the way much of medicine is perceived and practiced today. Prior to Framingham, atherosclerosis was thought to be an inevitable part of the aging process, and blood pressure was supposed to increase with age. The term risk factor, well recognized today, was coined by the study. High blood pressure and elevated cholesterol are now recognized as risk factors for heart disease, and much is done to reduce and ameliorate these factors.
Since the 1950s, the catheter angiogram has been the gold standard for detecting blockages in the arteries. Over six million operations or other interventions for heart disease are performed in American hospitals each year, with many done on patients who are having a second, third, or fourth procedure. New imaging techniques are constantly emerging that strive to improve and simplify the way heart disease is assessed. Multislice computed tomography (CT) angiography with high-resolution images, magnetic resonance imaging (MRI), and intravascular ultrasound (IVUS) (a miniaturized ultrasound probe to scan the cells that line the artery walls) are rapidly gaining their place in the emergency room and chest pain units. The gold standard still includes the catheter angiogram, but other less invasive detection-imaging techniques help assess the heart in a more comprehensive manner, and enable the understanding of the pathological changes to provide a wider range of therapeutic alternatives. Even lowly gall bladder surgery has changed from a major invasive procedure requiring many days in the hospital. Today, three quick incisions, a little vacuuming, and the patient is home cooking dinner by the end of the day. The change in medicine has been fun to watch. So, what's new in dentistry?
Caries as an infection
Traditionally, the terms caries and cavities/decay have been used interchangeably. Caries covers the continuum from the first infinitesimal level of demineralization, through the initial enamel or root lesion, through dentinal involvement, to eventual cavitation. Caries is an infection; cavities/decay is an outcome. They are not interchangeable terms. This distinction is critical in the changing paradigm of minimally invasive dentistry (MID). MID is a philosophy embracing the concept of performing the least amount of dentistry needed in any situation. This minimum may be extraction and placement of an implant in a person with Sjogren's, as opposed to more comprehensive and invasive treatment, such as restorations to a first, second, or third crown. MID is pushing dental professionals toward an increasing proactive approach focusing on disease prevention rather than just treating problems after they occur. The 20th century model of dentistry dealt with effects of disease; 21st century gold standard is practicing MID.
Since the late 1800s, the gold standard for detecting cavities has been the explorer with an educated clinician on one end. Just as with the catheter angiogram, explorers are not sensitive enough to detect early onset of infectious destruction until damage is well advanced and involves about one-third of the thickness of enamel. Just as there are ways to reduce and ameliorate factors leading to heart disease, there are ways to do the same with the enamel infection. Noninvasive quantitative diagnostic technologies detect infectious stages of an enamel infection and monitor changes over time. Early detection of enamel infections creates opportunities to heal damage with remineralization therapies. This is a modern approach that needs to become the new gold standard.
Quantitative gold standard
The subjective nature of detecting lesions in enamel with an explorer is what makes definitive diagnosis so nebulous. In truth, explorer sticks could be caused by a number of things, primarily the anatomy of the tooth. A narrow pit or fissure and a slightly heavy hand can cause resistance from removing the tip of the explorer from the tooth. To delve further into enamel breakdown, a mistimed explorer can break through the thin enamel layer, cavitating the lesion and, in effect, accelerating the process.
Explorers can and do pick up caries pathogens and — through operator transference — deposit the caustic biofilm into another location in a pit or fissure. Iatrogenic enamel disease is almost never discussed. Using the science of the last decade on laser fluorescence, enamel infections can be identified, quantified, and treated without damaging the enamel's flimsy outer covering.
Quantitative fluorescence assesses the enamel in a more comprehensive manner and enables the practitioner to understand the pathological changes. This provides a wider range of therapeutic alternatives. Fluorescence is often confused with laser or light density readings. Enamel density does change with breakdown, but a quantitative fluorescence of the metabolites of cariogenic bacteria is necessary to know what level of decay is present and whether nonsurgical therapies are working. Quantifying enamel density is akin to recognition of risk factors.
Time to embrace the change
Accepting laser light fluorescence as a viable diagnostic tool does not mean that diagnostics of the past century have been faulty. The reasons for not accepting the readings often revolve around the practitioner's ego. Acceptance merely means that science marches on. The buggy whip business was snapping in the 1800s. Today, reality no longer includes many buggy whips. No one today would consider the candlestick telephone as the standard of excellence in telephones, or Leeuwenhoek's microscope as a gold standard.
Just like CT, MRI and IVUS have increased the diagnostic ability of heart surgeons, so laser caries detection increases the diagnostic ability of the dental surgeon. The most important part of the diagnosis is the experience of the clinician and his or her ability to use advanced therapies to heal the tooth in a way that is far beyond what we had a short decade ago.
It may be helpful to note that the CRDTS (Central Regional Dental Testing Service, www.crdts.org) exam no longer refers to the explorer for caries detection to DDS candidates. New York University School of Dentistry stopped teaching it as a diagnostic tool beginning with its 2008 class.
The preservation of tooth structure is paramount in MID. As pivotal members of the MID dental team, hygienists should focus on prevention of disease and providing therapies to preserve tooth structure. The beauty of fluorescence is the ability of practitioners to get the exact same reading. No longer will the hygienist get a stick that the dentist cannot find. The DIAGNOdent (KaVo Dental Corporation, Lake Zurich, Ill., www.kavousa.com) detects the presence of the pathogens in the tooth enamel before the human eye can detect it or the explorer can create more damage.
The new gold standard comes in the shape of a red light stimulating cariogenic bacteria to glow green. The fluorescence becomes quantified and the clinician then has real information to make a decision about whether to surgically remove the infected portion of the tooth, or to turn the case over to the dental hygiene department for therapy. The presence of caries infection in one area should alert the clinician to the high likelihood of other areas of invisible breakdown.
Gimmicks abound in dentistry and sometimes it's difficult to separate what is worthwhile with what is not. Fluorescence has withstood the test of time in engineering and medicine. To look the other way or wait for more information is like turning the head away from space flight. The time is now to embrace a new gold standard for detecting caries infection.
Patti DiGangi, RDH, BS, is a speaker, author, practicing dental hygiene clinician, and American Red Cross authorized provider of CPR and first-aid training. She can be contacted through her Web site at www.pdigangi.com.
Shirley Gutkowski, RDH, BSDH, FACE, has been a practicing dental hygienist since 1986. She is codirector of CareerFusion (www.careerfusion.net). Gutkowski is also coauthor of The Purple Guide: Developing Your Clinical Dental Hygiene Career (www.rdhpurpleguide.com). She can be reached at [email protected].