This study was planned to evaluate the effects of xylitol-based chewing gums, sugar-free and sugared, on salivary flow and pH in young adults.

Chewing gum stimulates salivary flow, neutralizes and raises pH, and serves as a medium for administering therapeutic agents. However, global increases in sugar consumption have led to the development of chewing gums containing sugar substitutes, including polyols or non-fermentable sugars, of which the most commonly used are nutritive sweeteners such as sorbitol and xylitol.The use of polyol-containing chewing gums could play a role in preventing dental caries compared to not using gum or using sugared gum, most likely due to increased salivary flow and pH, improving enamel lesion remineralization; however, xylitol has anticariogenic properties influencing the reduction of dental plaque.

The study will conduct as a prospective randomized controlled trial. The population will consist of all enrolled students (1275 students) in the Dentistry program at the Catholic University aged 18 to 25 who voluntarily meet the inclusion criteria. The sample size will be 21 participants in each group, but it will be adjusted for a 15% loss of information or study dropout, thus requiring 25 participants in each group. Participants who meet the selection criteria will be probabilistically assigned using simple random sampling through a lottery system to four groups: the first group (G1) will consume xylitol chewing gum, the second group (G2) will consume sugar-free gum, the third group (G3) will consume sugared gum, and the fourth group (G4), the control, will chew paraffin.

Saliva samples will be taken between 8 to 10 am, taking into account that subjects should not have ingested food, smoked, or brushed their teeth at least 1 hour prior to sample collection. They will be asked to rinse their mouth with pure water to remove any food residue. Subsequently, they will be seated in a chair in an upright position with the head slightly tilted forward and eyes open, and the basal saliva sample will be taken as indicated by the established protocol of the collection method for unstimulated saliva by Tomas Seif. Before starting the test, they will be asked to swallow saliva, keep their mouth slightly open, and allow saliva to drain into the tube. The test lasts for five minutes and the salivary pH will be evaluated and recorded, labeled as T1. For stimulated saliva, the protocol dictated by the Faculty of Dentistry at the University of Southern California will be used. Through the drainage method, stimulated saliva will be collected in another pre-weighed test tube at three more time intervals: T2 from 5 to 10 minutes, T3 from 15 to 20 minutes, and T4 from 25 to 30 minutes after starting chewing gum consumption. The Measurement of saliva pH level will be evaluated immediately using a pH meter (BT-675 meter, Boeco-Germany), while the salivary flow will be evaluated by the difference in weight of the basal pH with the final pH.

Data will be entered into an Excel spreadsheet and data analysis will be performed. The analysis will be conducted using SPSS v.25, with descriptive data analysis. Chi-square test will be used for demographic data, Levene's test will determine data homogeneity, and ANOVA will determine differences in means, followed by Tukey's post-hoc comparison to find significant differences between group means, with a significance level of p<0.05.

The expected results, that the mean salivary pH and flow will differ among the different chewing gums

Inclusion Criteria:

• Participants must meet at least 20 teeth.
• Providing written informed consent. and being willing to comply with the study procedures.
• Being willing to comply with the study procedures

Exclusion Criteria:

• Individuals with systemic, infectious, or inflammatory diseases
• Individuals who are taking medications, antibiotics, or fluoride in the last month.
• Regular consumers of products and mouthwashes containing xylitol or sorbitol.
• Individuals with abnormal salivary flow (<1 ml/min).
• Pregnant women or those on contraceptive pill treatment.
• Individuals with abnormal dietary habits.
• Subjects with periodontal disease or presence of dental caries.

Individual Participant Data (IPD) underlying the results of the publication will be shared.

The data will be available from July 2024 to January 2025.

The data will be shared with anyone requesting it via email, stating the purpose of the request

Participants who meet the selection criteria will be probabilistically assigned using simple random sampling through a lottery system. An urn will be used to draw colors corresponding to a type of chewing gum