John: Patients undergoing dental treatment will often feel the discomfort of the gag reflex, and a new Cochrane Review in October 2015 sought out evidence on how to manage it. Lead author, Prashanti Eachempati from the Faculty of Dentistry at the Melaka-Manipal Medical College in Malaysia tells us what they found in this Evidence Pod.

Prashanti: Gag reflex is an involuntary defence mechanism to protect the pharynx and throat from foreign objects. It’s a natural phenomenon, but an exaggerated gag reflex can be a problem for both the dentist and the patient during dental procedures. Many procedures may cause this, such as obtaining impressions of the teeth, preparing teeth for various restorative procedures, extraction and taking intra-oral radiographs. Many management strategies have been proposed to control gagging over the decades, but as we found in our review, relatively few have been subject to robust research. Some of the strategies include anti-nausea medicines, sedatives, local and general anaesthetics, herbal remedies, behaviour therapy acupressure, acupuncture, and prosthetic devices.
We wanted to assess the effects of pharmacological and non-pharmacological interventions for the management of gagging in people undergoing dental treatment, on successful completion of dental procedure, reduction in the severity of gagging and adverse reactions. However, we found just one randomised trial. This had been done in Brazil in 2013, with just 33 participants. The trial evaluated the effects of acupuncture at P6 point versus non-penetrating sham acupuncture. The reported relevant outcome was reduction in nausea assessed according to the gagging severity index, gagging prevention index and visual analogue scale and we were also able to obtain information directly from the authors on our primary outcome: successful completion of dental treatment but there were no details on any adverse effects. Although the overall quality of the evidence was very low, due to relatively small sample size and low event rates, acupuncture at P6 was not shown to be better, or worse that sham acupuncture for the successful completion of dental procedure without any gagging problem. There was also no mean reduction in gagging as reported by the assessor in all three stages or in the patient-reported outcome.
In summary, the results of our Cochrane review are insufficient to determine whether or not acupuncture at P6 may be effective in reducing gagging and successfully completing maxillary impressions and we are not able to say anything about the other ways that have been tried for the management of the gag reflex. Well-planned randomised trials are needed of these interventions, with more clarity and uniformity in the variables they measure and report.

John: Information on the single randomised trial that was included in the current version of the review, along with the details of the extensive searching that was done by the Cochrane researchers are available in the full review, which you can find at Cochrane Library dot come, with a simple search for 'gag reflex'. That’s also the place to look for future updates of the review should additional randomised trials become available.