Effectiveness of an Oral Exercise Program for Xerostomia in Patients With Sjögren Disease

Sjögren disease (SjD) is a chronic systemic autoimmune disease characterized by lymphocytic infiltration of the exocrine glands, resulting in salivary and lacrimal gland dysfunction. Dry mouth resulting from salivary gland hypofunction is one of the most common and burdensome manifestations of the disease. Salivary gland hypofunction contributes to chronic xerostomia, impaired oral comfort, difficulties in speaking and swallowing, alterations in taste perception, and reduced oral health-related quality of life.

Although dry mouth has been considered a consequence of immune-mediated salivary gland destruction, accumulating evidence suggests that glandular pathology alone cannot fully explain the severity of symptoms experienced by patients. The degree of exocrine gland destruction correlates only weakly with glandular function, and objective measures of salivary secretion do not consistently correspond with patients' subjective perception of oral dryness. These findings suggest that the symptoms experienced by patients cannot be explained solely by immune-mediated glandular destruction, indicating that additional mechanisms may contribute to xerostomia in SjD.

Current management of xerostomia in SjD includes saliva substitutes, chewing gum, systemic sialogogues, acupuncture, and electrical stimulation. However, current evidence supporting non-pharmacological interventions remains limited, and no specific intervention can currently be recommended with confidence because of the low quality and heterogeneity of the available studies. Consequently, there remains an unmet need for safe, accessible, and evidence-based non-pharmacological interventions for xerostomia in SjD.

Structured oral exercise programs have shown potential benefits for salivary secretion, oral motor function, and xerostomia symptoms in other populations, including older adults and individuals with radiation-induced xerostomia. Repeated oral motor activity may stimulate salivary secretion through mechanical and sensorimotor stimulation of the oral cavity. However, whether structured oral exercises improve xerostomia-related outcomes in patients with SjD remains unknown.

Therefore, the primary aim of this randomized controlled trial is to investigate whether a structured oral exercise programme, in addition to oral hygiene education and usual medical care, reduces xerostomia severity. Secondary aims are to evaluate its effects on salivary flow, oral health-related quality of life, and swallowing symptoms.

• Oral exercise (Other): The oral exercise program will consist of a series of simple oral motor exercises involving coordinated movements of the jaw, lips, cheeks, and tongue. The program was developed based on previously published oral exercise protocols in older adults and patients with xerostomia, with modifications for patients with SjD.

Primary outcomes

• Xerostomia Inventory (XI) [baseline, week 6, week 12]: The XI is a patient-reported assessment tool designed to evaluate the sensation of dry mouth. It consists of 11 items using a 5-point Likert scale, with each item scored from 1 (never) to 5 (very frequently). The total score ranges from 11 to 55, with higher scores indicating a more severe level of dry mouth.

Secondary outcomes

• EULAR Primary Sjögren's Syndrome Patient-Reported Index (ESSPRI) [baseline, week 6, week 12]: ESSPRI was developed to assess-based on patient self-reporting-the symptoms of dryness, fatigue, and pain experienced by individuals with pSS over the preceding two weeks. These three symptoms are evaluated individually, with the severity of each rated on a scale from 0 (absent) to 10 (most severe). Individuals are asked to score the severity of their symptoms within this range. The total score is calculated by averaging the component scores. An ESSPRI score below 5 is considered an acceptable disease state, whereas a score of 5 or higher is regarded as an indication of high disease activity.
• Dryness severity [baseline, week 6, week 12]: The severity of perceived mouth, eye, and nose dryness will be assessed using a 100-mm Visual Analogue Scale (VAS); over the preceding two weeks.
• unstimulated whole salivary flow rate [baseline, week 6]: Unstimulated whole saliva will be collected for 5 minutes. Participants will continuously expectorate the accumulated whole saliva into a pre-weighed collection tube without swallowing
• stimulated whole salivary flow rate [baseline, immediately post-first exercise session, week 6]: Stimulated whole saliva will be collected for 5 minutes using a standardised citric acid stimulation procedure. A cotton-tipped applicator soaked in 2% citric acid will be applied to the lateral borders of the tongue at the beginning of the collection and reapplied every 60 seconds. Participants will continuously expectorate the accumulated whole saliva into a pre-weighed collection tube without swallowing
• Oral Health Impact Profile-14 [baseline, week 6, week 12]: Oral health will be evaluated with OHIP-14 using a 5-point Likert scale (ranging from "4=very often" to "0=never"). The total score obtained by totaling the item for the 14 items at the same frequency; the total score ranged from 0 to 56.
• Eating Assessment Tool-10 [baseline, week 6, week 12]: The EAT-10 is a self-report assessment tool used to identify individuals at high risk for swallowing disorders. It consists of 10 items, each scored on a five-point Likert-type scale ranging from 0 (no problem) to 4 (severe problem). A score of three or higher on the EAT-10 indicates the possible presence of dysphagia.
• Global Rating of Change scale [week 6, week 12]: Participants' perceived change in oral dryness will also be evaluated using a Global Rating of Change scale. (much better, a little better, no change, a little worse, much worse).

Sex: All, ages: 18 Years to any

Inclusion Criteria:

* a diagnosis of SjD based on the 2016 ACR/EULAR Classification Criteria;
* ≥18 years of age;
* residual stimulated whole salivary flow rate (≥0.05 ml/min);
* presence of subjective xerostomia (Visual Analogue Scale ≥ 50);
* stable pharmacological treatment for at least 4 weeks before enrolment;
* provision of written informed consent. -

Exclusion Criteria:

* history of head and neck radiotherapy,
* severe cognitive impairment (i.e., dementia)
* psychiatric disorders preventing participation,
* neurological disorders affecting oral motor function,
* participation in structured oral motor or swallowing rehabilitation within the previous 2 months,
* inability or unwillingness to comply with the study protocol.