Hyposalivation is a condition that has increased in frequency, primarily due to the degeneration of salivary glands caused by aging, polypharmacy, chronic or autoimmune diseases, or radiation treatments. Most of these factors are associated with the elderly, a growing demographic due to the aging population. Therefore, addressing this condition has become crucial in our population, as has understanding how it affects their quality of life. Given that saliva plays a vital role in maintaining the oral mucosa, tooth structure, initiating digestion, and even speech, a long-term treatment to stimulate salivary production would be extremely helpful in resolving these problems. Currently, only palliative measures that temporarily cover or lubricate the oral cavity and its structures are available.

Among the most innovative treatments is neuroelectrical stimulation (TENS) as an adjunct in the therapy of dry mouth, which has shown improvement; however, this improvement has not been quantified through objective measurements that would allow for determining the quantity and quality of saliva, nor in the long term. Likewise, the patient's quality of life affected by this condition has not been assessed.

Therefore, the objective of this project is to evaluate the effect on salivary quality and quantity after the application of neuroelectrical stimulation as a treatment for patients with dry mouth, as well as their quality of life.

Participants: Patients attending the Orocentro Clinic of the Faculty of Dentistry at the Autonomous University of the State of Mexico with dry mouth symptoms who, upon diagnosis, present with hyposalivation, and who provide their consent and assent to participate in the study.

Sampling: Non-probabilistic, quota and convenience sampling.

Procedure A clinical examination will be performed to identify patients with dry mouth for confirmatory diagnosis and collection of clinical data. If necessary, a biopsy will be taken to identify Sjögren's disease. After obtaining informed consent and assent, baseline salivary samples will be taken for comparison after neuroelectrostimulation treatment. The Xerostomia Quality of Life Questionnaire will also be administered to assess any changes in quality of life following treatment.

To evaluate oral moisture, the time it takes for saliva droplets to form on the inner surface of the buccal mucosa of the lower lip will be measured; this should be less than 60 seconds.

Subsequently, the stimulated saliva will be collected by instructing the patient to chew paraffin gum for 5 minutes and then pour all the saliva produced into a calibrated cup. Saliva samples will be collected between 10 and 11 a.m. on study days to standardize the effect of circadian rhythms on salivary parameter assessment. All participants will be instructed to refrain from chewing gum or candy, eating, drinking any liquids or alcohol, smoking, or brushing their teeth for approximately two hours prior to sample collection.

Salivary pH and buffering capacity will be evaluated using reagent strips (Saliva-Check Buffer (GC, Alsip, IL, USA)) by immersing them in the stimulated saliva sample. The value will be assigned by colorimetric comparison with the manufacturer's chart. Saliva viscosity will be visually determined. Photographic records of the measurements will be taken to clarify any doubts in their interpretation. After determining the salivary values, and if the participant requests and accepts it, neuro-electrostimulation will be applied. This application will be performed using self-adhesive electrodes (Theratrode or Physiotrode). Before placing the electrodes, the skin area corresponding to the parotid and submandibular glands will be cleaned. The electrodes will be placed bilaterally in this area, and the BTL device will be programmed to TENS current mode with parameters of 4 Hz and a wavelength of 250 µs. The intensity will be adjusted until a visible contraction of the facial muscles is achieved and the patient tolerates it.

The Sialometry will be obtained before and after therapy. TENS will be applied twice a week for three weeks. If no changes are seen, the therapy will be changed to magnetic fields.

Participants will be followed up at 6 months, during which maintenance therapy will be carried out, and again 1 year after the application of the first therapy.

Quality of life and identification of oral lesions will be assessed at two time points (before and at the end of the study). This therapy may vary depending on the severity of the case (hyposalivation/Sjögren's syndrome).

Many of these patients require tooth extractions due to dental demineralization and loss of healthy supporting tissues. In these cases, the demineralization of the extracted tooth caused by the lack of mineral content provided by saliva will be evaluated through Vickers microhardness and Diagnodent measurements.

Statistical analysis The results will be subjected to the SPSS statistical package, version 26, obtaining descriptive statistics and checking the normality of the corresponding samples, in order to apply the Student's T test for paired samples, ANOVA of repeated measures and Pearson correlation to relate sociodemographic data, with a p-value≤0.05 to find statistically significant differences.

Inclusion Criteria:

• Patients diagnosed with dry mouth symptoms.
• Patients who wish to participate in the study.
• Patients who allow saliva samples to be collected before, during, and after treatment.
• Patients who allow the application of transcutaneous electrical nerve stimulation (TENS).
• Patients who do not have any active oral infections.
• Patients who attend all sialometry assessments and physiotherapy sessions and complete both quality of life questionnaires (initial and final).

Exclusion Criteria:

• Patients with any other mucosal alteration.
• Patients who do not wish to participate in the study.
• Patients who do not allow the collection of saliva samples.
• Patients who do not allow the application of transcutaneous electrical nerve stimulation (TENS).
• Patients with any infectious process in the oral cavity.
• Because the study requires the use of low-frequency pulse currents, participants with pacemakers, defibrillators, hearing aids, or cochlear implants will also be excluded from the study.

Anonymized individual data supporting the study results will be shared with qualified researchers upon reasonable request, following publication of the results, through an institutional repository and under a data use agreement.

The study results will be shared upon reasonable request, following publication of the results

Access to anonymized individual data will be available to qualified researchers who submit a methodologically sound scientific proposal, approved by the research team. Access will be subject to the signing of a data usage agreement.