Comparison of Gum® HydralTM Moisturizing Gel and Biotene® Oral Gel in Dry Mouth Sensation Reduction

After clinical history analysis subjects were randomized, using a stratified randomization list which considered as main prognostic factor the presence of a systemic pathology/drug assumption responsible for the onset of xerostomia, into 2 parallel groups: one group of 20 patients receiving GUM® Hydral® Moisturizing Gel (test group); one group of 20 patients receiving Biotene® Oral Balance Gel (control group).

In order to guarantee the allocation concealment, the randomization list was prepared after patient inclusion in the study by a centralized office, responsible for the integrity of the whole randomization protocol, and after that treatment products presented in kits were distributed to each patient. Blinding of the evaluators and patients was obtained using the same white anonymous packages for both tested products. The stratification was obtained separating the patients in two groups, with and without the presence of a systemic pathology/drug assumption responsible for the xerostomia onset, and then generating two separated randomized lists.

At the beginning of the trial (t0) each patient received a print-out summarizing the instructions for use of the products: they were instructed to apply during a 28 days treatment period 1 to 2 cm of gel to gums, oral mucosa membrane and tongue, repeating as many times as necessary, and to brush their teeth with GUM® Technique® Pro soft compact toothbrush (Sunstar Europe S.A., Etoy, Switzerland) using GUM® Hydral® Toothpaste (Sunstar Europe S.A., Etoy, Switzerland) at least twice a day. The first application was done by the participants themselves under the supervision of the same operator that provided them both oral and written usage instructions. They had to refrain from using any other commercial mouthrinse, toothpaste or saliva supplements during the trial and they were asked to complete a "patient questionnaire" at the same time of the day (in the morning, at the hospital prior to their clinical examination) at t0, t1 (after 1st week), t2 (2nd week), t3 (3rd week) and at the end of the trial, t4 (4th week), and a "daily journal".

The "patient questionnaire" was used to record the severity of the dry mouth sensation and changes in the symptoms (thanks to a VAS scale and dichotomous variables). It also contained questions to evaluate the quality of life (QoL) improvement (psychological impact and social well-being), the convenience of use and overall feeling (at t4), and the organoleptic properties of the tested products.

In the "daily journal", patients indicated on a dedicated calendar the times of product use, they reported their subjective sensation of oral dryness 3 times a day (morning, around 12 AM - 2 PM, evening) on a Visual Analogue Scale (VAS) ranging from 0 (well lubricated mouth) to 10 (worst possible dry mouth feeling), and they answered the following two questions (once a day at the same time): "How many minutes after the use of the gel did you feel dry mouth relief?" and "How long (expressed in minutes) did the dry mouth relief last (after the use of the gel)?" to record the perceived speed and duration of effects of the products and their pleasantness of use.

The salivary flow rate is the amount of saliva produced by salivary glands in the time unit and it can be divided into unstimulated (which is independent of the presence of stimuli as food and chewing) and stimulated (secreted in response to sensory stimulation, gustatory and masticatory mainly)40.

At t0, after one hour of abstinence from drinking, eating and smoking, the patients were characterized by means of an unstimulated (Whole Resting Saliva - WRS) and a stimulated (Whole Stimulated Saliva - WSS) whole saliva flow determination using the spitting method between 11.00 and 12.00 a.m. under controlled temperature and humidity conditions37,39,40,41. WRS was determined collecting saliva produced during a time span of 5 minutes37; subsequently, WSS was determined collecting saliva produced during a time span of 1 minute, after 5 minutes chewing a paraffin soft ball.

The enrolled subjects were submitted to a rigid protocol of behavioral norms in preparation for salivary collection37,38,39,40,41. Patients were advised to keep a relaxed attitude and not to practice sports and/or physical efforts in the two days prior to the salivary collection37,41. On the sampling day, participants had to be free from symptoms of fever and/or cold; if they were hungry or thirsty, they could eat or drink water, but immediately afterwards they had to brush their teeth with a provided toothpaste37. During the collection periods, subjects remained comfortably seated and swallowed residual saliva present in the mouth before the beginning of tests37. Then, with the head down and the mouth slightly open, saliva was allowed to drip from the lower lip into a pre-weight, dry, deionized and sterilized plastic test tube37.

At t0, t1, t2, t3, and t4 the same operator, blind regarding patient treatment group assignment, completed the ROAG (Revised Oral Assessment Guide) scale and reported any local irritation or allergic reaction caused by the product. In case of changes in medication assumption changes during the study period, patients were excluded from the sample.

After the conclusion of the data collection, patients were medically followed in the subsequent six months in order to recognize any long-term side effect appearance (t5).