Prevention, screening, and a chance of rain.

Michael Glick, DMD P revention, health screening, and assessing risk are concepts that lie at the core of medicine and dentistry and affect how all of us practice. In order to apply these concepts effectively, we must be clear in defining them. Prevention can be separated into primary, secondary, tertiary, and quaternary prevention. Primary prevention usually refers to an attempt to reduce a clinical outcome among people who have yet to develop disease—fluoride for children without caries, for example. Secondary prevention is an activity meant to reduce the morbidity and mortality in asymptomatic patients having an already established disease— fluoride for people with incipient caries. Tertiary prevention is intended to reverse, arrest, or delay progression of an already established disease— remineralization of carious lesions. And finally, quaternary prevention has been defined as reducing overmedicalization (overdiagnosis and overtreatment) to prevent the potential for iatrogenic harm—placing restorations in teeth with questionable caries lesions. “Overdiagnosis” denotes diagnosis of conditions that will never cause symptoms, harm, or death. “Overtreatment” refers to unnecessary treatment that provides no patient benefit. Overtreatment often results from the reluctance of health care providers to acknowledge new scientific findings and accept more appropriate outcome measures. Unfortunately, overtreatment significantly contributes to rising health care costs in the United States. All of these types of prevention have been linked to risk or surrogate markers associated with specific diseases. Treating risk factors does not always prevent disease, as the same risk factors may not always be causative for all patient populations. Treatment for high levels of total or low-density lipoprotein cholesterol, for example, may not benefit everyone taking cholesterol-lowering drugs, as it has been shown that those without clinically manifested cardiovascular disease may not benefit from taking statins. Statins are associated with some dire side effects and may, therefore, in some populations, cause more harm than good. Populations and individual patients at risk for developing disease can be identified and assessed by screening. The general purpose of screening is to reduce overall morbidity, mortality, and to improve future quality of life, but the actual intent of a particular screening must be determined before embarking on a screening plan. Is the purpose of screening to identify asymptomatic patients at risk for developing disease? To diagnose the presence of disease (diagnostic screening)? Or is it to monitor progression of disease? Two different screening schemata have generated intense debate: prostate-specific antigen