Dental Fear May Have Genetic Roots

Dentistry Today


Dental fear is real, with previous studies suggesting it affects up to 25% of the common population. The consequences are real too, as people who avoid the dentist out of fear wind up with significant though preventable oral health problems. While many studies trace these phobias to childhood experiences, new work from West Virginia University and the University of Pittsburgh suggests they might have some genetic causes.

The researchers surveyed 1,370 subjects between the ages of 11 and 74 years in a family-based cohort study, measuring their dental fear and fear of pain. According to the data, dental fear was 30% heritable among those surveyed, and fear of pain was 34% heritable. The researchers also found a substantial genetic correlation between dental fear and fear of pain, suggesting they are genetically related, though from distinct phenotypes.

Cameron L. Randall, MS, a doctoral candidate in the department of psychology at West Virginia University and the Center for Oral Health Research in Appalachia shared his insights about the study, “Toward a Genetic Understanding of Dental Fear: Evidence of Heritability,” which was published by Community Dentistry and Oral Epidemiology

Q: Generally speaking, why is fear an obstacle in dental treatment? 

A: Most critically, fear is an obstacle because it results in avoidance of dental treatment. That avoidance can range in severity from the delaying of a dental appointment to complete avoidance of dental treatment for many, many years. Of course, with avoidance of dental treatment comes poorer oral health.

Avoidance of dental treatment also increases the likelihood of a negative experience with dentistry once a patient finally presents to the dental clinic (typically out of absolute necessity, often driven by intense pain), and that negative experience reinforces the patient’s fear, making them likely to avoid treatment in the future.

This phenomenon is known as the “vicious cycle” of dental fear, and being caught in the cycle has obvious consequences for oral and systemic health. In addition to avoidance of dental treatment, fear also can result in patients feeling uncomfortable during dental treatment, causing patient distress and complicating the provision of treatment for the clinician.

Q: What is the distinction between dental fear and fear of pain?

A: Fear of pain describes a general apprehension about and avoidance of pain and pain-related stimuli, whereas dental fear is more specific and circumscribed, describing apprehension about and avoidance of dental treatment-related stimuli, including dental visits. Many patients who suffer from dental fear report fear of pain associated with dental treatment. However, there are a number of patients who have dental fear and avoid dental treatment but are not fearful of pain and may instead have dental fear rooted in claustrophobia, blood-injection-injury fears, and/or fear of negative evaluation or embarrassment.

Q: Fear seems subjective. What prompted the investigation into genetic roots?

A: Indeed, the experience of fear is a subjective one, and what may trigger a significant fear response for one patient may have a muted or even no emotional effect on another patient. Still, there are very objective consequences of subjective emotional experiences, and in the case of fear the most important consequence is avoidance behavior.

Psychology researchers have long worked to understand individual differences in subjective emotional experiences and the etiologies of maladaptive emotional response (eg, fears that are so pronounced they result in unhealthy or impairing avoidance behavior). Within the last decade, the role of genetics in the development and maintenance of fear and anxiety has interested psychologists. 

For example, how do genetic predispositions make an individual more or less likely to develop an anxiety disorder or phobia, and what are the mechanisms by which genetic variation contributes to one’s susceptibility to develop problematic anxiety or fear? Dental fear researchers have joined other anxiety researchers in trying to establish a more comprehensive and complete conceptualization of fear so as to develop better interventions for the reduction of problematic fear/anxiety.

Our investigation of the genetic underpinnings of dental fear was prompted by a need to more fully understand the causes of dental fear, particularly because biology and the biology-environment interaction have not received as much scientific attention in research that has, until recently, focused primarily on the important roles of cognition, experience, and environment.

Q: What effect does learned behavior have on dental fear? In other words, if a parent expresses fear of or discomfort with the dentist, can children develop that fear themselves? 

A: Learned behavior has an enormous effect on dental fear. In fact, learning from prior experiences or social learning (eg, learning from watching a parent respond to dental treatment or hearing what a parent has to say about dental treatment) likely influences dental fear most strongly. Psychologists and other behavioral scientists recognize and appreciate the very important and profound role of learned behavior on dental fear, and thus the best interventions for reducing dental fear typically involve a strong behavioral or learning component.

Q: What genetic role does fear play? Is it tied to the “fight or flight” response?

A: We don’t yet know with any certainty the mechanism(s) by which genetic variation influences dental fear. Our study suggesting that dental fear is heritable, along with 3 studies by other research groups demonstrating a role of genetics in the development of dental fear, are prompting future research to determine the exact ways genes may influence dental fear. There are a number of plausible mechanisms that need to be investigated before any firm conclusions can be drawn. 

For example, there may be genetically determined differences in pain sensitivity that make a patient more or less likely to have negative dental treatment experiences that would promote the development of dental phobia. Relatedly, there may be genetically determined differences in the rate at which a patient metabolizes local anesthesia such that some individuals experience less numbness and thus a higher likelihood of experiencing pain, making them more likely to have negative dental experiences that could cause dental fear. And, there may be genetically determined differences in anxiety sensitivity or an “overactive” fight-or-flight response that make a patient more or less likely to develop problems with fear/anxiety generally.

Of course, other mechanisms may be responsible for the genetic influence on dental fear. Additional research is required to definitively answer this question.

Q: Potentially, how could dentists use this understanding of the genetic role in dental fear to improve treatment?

A: At this point, it is too early to offer concrete recommendations to dental clinicians for them to improve treatment based on our study findings. Still, the study results suggesting that there is a role of genetics in dental fear should prompt dentists and other dental practitioners to consider that there may be biologically driven individual differences in pain and/or fear susceptibility that could influence the patient’s likelihood to have problems with dental fear. Approaching each patient uniquely to respond to his or her individual presentation of fear is the best way to ameliorate that fear so as to improve patient comfort, adherence to recommended treatment, and dental treatment outcomes.

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