Effect of Experimental Pregabalin Gel in Controlling Cervical Dentin Hypersensitivity: a Randomized, Double-blind, Controlled Clinical Study

To obtain the experimental pregabalin gel, a carbopol 940 gel base was used. To prepare the base gel for the formulation, each component was weighed on an analytical balance and, after 24 hours, the components were taken to a mechanical shaker, rotating at 1000 rpm for 10 minutes. 50% triethanolamine was added to adjust the pH to ±6 and complete gel formation. The concentrations of the components of the initial base formula were adjusted to obtain a homogeneous, transparent gel with good consistency. A PG solution (10 mg/ml) was prepared by diluting the drug, which is presented as a white, crystalline powder (Vardhman Chemtech Ltd, Punjab, India), with purified water. The solution was stirred for 10 min in a water bath (Taitec) and centrifuged at 4°C for 10 min. The supernatant obtained was collected and then incorporated into the 1% carbopol-based gel.

This formulation has already been evaluated in a previous study regarding quality standards, physical/chemical characterization, cytotoxicity and subjected to stability analyzes (preliminary and accelerated). Its characteristics indicate that it is a favorable formulation for clinical application.

This randomized clinical study will follow the guidelines for clinical trials recommended by CONSORT (Consolidated Standards Of Reporting Trials) and will be submitted to the Human Research Ethics Committee of the Institute of Health Sciences at the Federal University of Pará (CEP-ICS/UFPA). All selected participants who agree to participate in the research will be informed about the benefits, risks, methods, and goals of the study before consenting to their participation through the Informed Consent Form declaring that the participants agree with all the steps to be taken. The participants can withdraw from the research at any time, following the principles of the Declaration of Helsinki.

This randomized clinical trial will be parallel, double-blind, placebo-controlled and all clinical interventions will be conducted in the clinics of the Faculty of Dentistry of the Federal University of Pará (FOUFPa). The research will consist of three groups: a placebo control group (CG) with gel without any active ingredient, a group with potassium nitrate gel (Ultradent, South Jordan, UT, USA) (GNK), and an experimental group with gel 10% Pregabalin (GPG). Applications will be carried out in 3 sessions with an interval of 72 hours between each one. Sensitivity recording will be performed at T0 (baseline), T1 (after the first session), T2 (after the second session), T3 (after the third session), T4 (7 days after the last session), and T5 (one month after the last session) and T6 (3 months after the last session).

A questionnaire (QEDH-15) will be applied to evaluate the impact of desensitizing treatment on improving the participants' oral health-related quality of life (HRQoL). The questionnaire will be applied at baseline (T0) and the last sensitivity record (T6). Higher QEHD-15 scores indicate a negative impact on the oral health-related quality of life (OHRQoL) of research participants.