Exploring Dental Pain Relief: Targeting stress hormone receptors Dr. Kevin Rowland is tackling one of our culture’s most iconic notions of suffering—pain in the dental chair. An associate professor and section head of physiology in the Department of Applied Dental Medicine, Rowland pursues all possible means to alleviate dental pain. “Pain is a big part of dentistry because it brings people to the dentist and it also keeps people away from the dentist,” he said. “If we can alleviate the painful experiences that people have when they go to the dentist, then they’re more likely to return on a regular basis and improve their overall health.” Despite the frequent occurrence of dental pain, medications that are used to mitigate the pain often come with negative side effects such as addiction (in the case of narcotics) or liver, kidney and hearing problems (in the case of ibuprofen, acetaminophen and aspirin). Through multiple research projects, Rowland is discovering improved ways to ease both acute and chronic pain more effectively. In one research study, Rowland explores a new drug called tetracaine anesthetic paste (TAP). TAP is a topical anesthetic that lessens the pain of the process of fixing the tooth. An SIU School of Dental Medicine graduate and one of his patients, who is a pharmacist, originally formulated the paste and brought it to Rowland for further research. Rowland’s goal is to examine the short and long-term effects of the drug on the oral cavity.
The first stages of the study involving animal models showed promising results and allowed Rowland to advance the study to the next level. “First, we wanted to find out what kind of changes we could expect in the oral cavity. We investigated the cellular changes that occurred in the oral mucosa of rats,” he said. “We found only transient changes (meaning no negative long-term effects), which allowed us to move quickly into the testing of volunteer human subjects.” Upon application of TAP on the oral cavity, volunteer patients are submitted to an electric pulp tester which sends minute amounts of electricity into the tooth. The pulp is the area of pulpous material containing nerves inside the hard enamel and dentin. “It seems that when we apply it on a tooth, the tooth becomes completely numb,” he said. “We are seeing that it is highly effective. When the maximum current setting for the pulp test is applied, the patients feel no pain when normally they would jump out of their chairs.” Rowland’s interest in pain relief has similarly led him to study the role hormones and hormone receptors play in the registration of pain. His second study examines stress hormone receptors in the pulp and their ability to cause the release of natural analgesics. Rowland determined that stress hormone receptors are present in the pulp and that, under painful conditions, the number of receptors increases,
allowing the pulp to become more sensitive to the stress hormones. “We are now conducting a follow-up study in which we attempt to correlate levels of pain with natural opioid release from the receptors. We want to know when it would be appropriate to target those stress hormone receptors in order to stimulate this release of opioids. Also, would there even be enough opioid released to fully alleviate the pain?” In the end, Rowland hopes his research will improve future methods of alleviating dental pain. “We are looking at different dental procedures that could benefit from this research. Someday, a cavity filling may be done without any use of injections,” he said. Without the pain of injections, one wonders if more people will be willing to make the trip to the dental chair?
“If we can alleviate the painful experiences that people have when they go to the dentist, then they’re more likely to return on a regular basis and thus, improve their overall health.”