Salivary Function and Dental Changes During GLP-1 Therapy

NCT07720466 | Not Yet Recruiting

• 1 other identifier: BSEU-ONDER-003
• Study Type: observational
• Target: 40
• Locations: 1 country
• Sites: 1

Brief Summary

People who use glucagon-like peptide-1 (GLP-1) receptor agonists, such as semaglutide and tirzepatide, may experience changes in their oral health. Some people report dry mouth, changes in saliva, and increased wear of their teeth after starting these medicines. However, little is known about whether these medicines affect saliva and dental hard tissues. The purpose of this study is to evaluate changes in salivary calcium levels, salivary function, and dental hard tissues in adults who begin treatment with semaglutide or tirzepatide for obesity. Approximately 40 participants will be enrolled before starting GLP-1 receptor agonist therapy. Oral examinations, standardized intraoral photographs, saliva samples, and body weight measurements will be obtained before treatment and again after three months. Saliva samples will be analyzed for calcium concentration, pH, and salivary flow rate. Dental hard tissue changes will be assessed using the Basic Erosive Wear Examination (BEWE) index. The findings from this study may improve understanding of the effects of GLP-1 receptor agonists on oral health and help healthcare professionals identify and prevent possible dental complications during treatment.

Conditions

Obesity; Dental Erosion; Saliva Collection; Saliva Altered

Outcome Measures

Primary Outcomes (1)

• Change in salivary calcium concentration

  Change in salivary calcium concentration (mg/dL) measured in unstimulated whole saliva using a colorimetric biochemical assay between baseline and 3 months after initiation of semaglutide or tirzepatide therapy.

  Baseline and 3 months

Secondary Outcomes (5)

• Change in salivary pH

  Baseline and 3 months

• Change in unstimulated salivary flow rate

  Baseline and 3 months

• Change in dental hard tissue status

  Baseline and 3 months

• Change in body mass index

  Baseline and 3 months

• Change in body weight

  Baseline and 3 months

Study Arms (2)

Semaglutide Group

Adults with obesity who are prescribed semaglutide by an endocrinologist according to routine clinical indications. Participants will undergo baseline oral examination, standardized intraoral photography, body weight assessment, and unstimulated whole saliva collection before initiating treatment. The same evaluations will be repeated after 3 months of therapy. Saliva samples will be analyzed for calcium concentration, pH, and salivary flow rate, and dental hard tissue changes will be assessed using the Basic Erosive Wear Examination (BEWE) index.Changes in salivary calcium concentration, salivary pH, salivary flow rate, BEWE scores, body weight, and standardized intraoral photographs will be compared between baseline and the 3-month follow-up, as well as between the two treatment groups.

Procedure: Unstimulated Whole Saliva Collection; Procedure: Salivary Analysis; Procedure: Oral Examination and BEWE Assessment; Procedure: Standardized Intraoral Photography

Tirzepatide Group

Adults with obesity who are prescribed tirzepatide by an endocrinologist according to routine clinical indications. Participants will undergo baseline oral examination, standardized intraoral photography, body weight assessment, and unstimulated whole saliva collection before initiating treatment. The same evaluations will be repeated after 3 months of therapy. Saliva samples will be analyzed for calcium concentration, pH, and salivary flow rate, and dental hard tissue changes will be assessed using the Basic Erosive Wear Examination (BEWE) index.Changes in salivary calcium concentration, salivary pH, salivary flow rate, BEWE scores, body weight, and standardized intraoral photographs will be compared between baseline and the 3-month follow-up, as well as between the two treatment groups.

Procedure: Unstimulated Whole Saliva Collection; Procedure: Salivary Analysis; Procedure: Oral Examination and BEWE Assessment; Procedure: Standardized Intraoral Photography

Interventions

Salivary Analysis PROCEDURE

Saliva samples will be centrifuged at 3,000 × g for 10 minutes at 4°C. Salivary pH will be measured, and the supernatant will be stored at -80°C until calcium concentration analysis.

Semaglutide Group; Tirzepatide Group

Oral Examination and BEWE Assessment PROCEDURE

Standardized oral examinations will be performed at baseline and after 3 months. Dental hard tissue status will be evaluated using the Basic Erosive Wear Examination (BEWE) index by calibrated examiners.

Semaglutide Group; Tirzepatide Group

Standardized Intraoral Photography PROCEDURE

Standardized intraoral photographs will be obtained at baseline and after 3 months using a predefined photographic protocol. Images will be coded and evaluated for dental hard tissue changes by blinded assessors.

Semaglutide Group; Tirzepatide Group

Unstimulated Whole Saliva Collection PROCEDURE

Unstimulated whole saliva will be collected for 10 minutes at baseline and after 3 months. Participants will refrain from eating, drinking, smoking, chewing gum, and performing oral hygiene procedures for at least 2 hours before sample collection. Salivary flow rate will be calculated, and saliva samples will be processed for pH measurement and calcium analysis.

Semaglutide Group; Tirzepatide Group

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

The study population will consist of adults (≥18 years) with obesity (BMI ≥27 kg/m²) who are prescribed semaglutide or tirzepatide for obesity management according to routine clinical practice. Participants will be recruited before initiating GLP-1 receptor agonist therapy at the Endocrinology and Metabolism outpatient clinic and will undergo standardized oral examinations and saliva assessments at baseline and after 3 months of treatment.

You may qualify if:

• Adults aged 18 years or older.
• Body mass index (BMI) ≥27 kg/m².
• Clinical decision by an endocrinologist to initiate semaglutide or tirzepatide therapy for obesity management.
• No previous treatment with GLP-1 receptor agonists.
• Willingness to participate and ability to provide written informed consent.
• Willingness to attend both the baseline and 3-month follow-up visits.

You may not qualify if:

• Previous use of any GLP-1 receptor agonist.
• History of head and neck radiotherapy.
• Sjögren syndrome or other systemic diseases affecting salivary gland function.
• Chronic kidney disease.
• Pregnancy or breastfeeding.
• Use of medications known to markedly affect salivary secretion.
• Active orthodontic treatment.
• Severe dental erosion requiring restorative treatment at baseline.
• Edentulism or the absence of anterior teeth required for dental hard tissue assessment.
• Inability or unwillingness to comply with the study protocol or attend the 3-month follow-up visit.
• History of eating disorders associated with recurrent self-induced vomiting (e.g., bulimia nervosa).
• Medical conditions causing persistent vomiting or severe gastroesophageal disease unrelated to GLP-1 therapy.

Sponsors & Collaborators

• Bilecik Seyh Edebali Universitesi: lead

Study Sites (1)

Department of Periodontology, Bilecik Seyh Edebali University Faculty of Dentistry

Bilecik, Merkez, 11100, Turkey (Türkiye)

Location

Related Publications (3)

• Kim YJ, Kim YB, Kim S, Choi TY, Park HK, Choi SY. Chlorpromazine induces hyposalivation by inhibiting muscarinic Ca2+ signaling in salivary glands. Naunyn Schmiedebergs Arch Pharmacol. 2026 Jan;399(1):941-951. doi: 10.1007/s00210-025-04438-8. Epub 2025 Jul 23.

  PMID: 40699237 BACKGROUND

• Mawardi HH, Almazrooa SA, Dakhil SA, Aboalola AA, Al-Ghalib TA, Eshky RT, Niyazi AA, Mawardi MH. Semaglutide-associated hyposalivation: A report of case series. Medicine (Baltimore). 2023 Dec 29;102(52):e36730. doi: 10.1097/MD.0000000000036730.

  PMID: 38206684 BACKGROUND

• Barac M, Roganovic J. GLP-1 Receptor Signaling and Oral Dysfunction: A Narrative Review on the Mechanistic Basis of Semaglutide-Related Oral Adverse Effects. Biology (Basel). 2025 Nov 23;14(12):1650. doi: 10.3390/biology14121650.

  PMID: 41463424 BACKGROUND

MeSH Terms

Conditions

Obesity; Tooth Erosion

Interventions

Diagnosis, Oral

Condition Hierarchy (Ancestors)

Overweight; Overnutrition; Nutrition Disorders; Nutritional and Metabolic Diseases; Body Weight; Signs and Symptoms; Pathological Conditions, Signs and Symptoms; Tooth Demineralization; Tooth Diseases; Stomatognathic Diseases; Tooth Wear

Intervention Hierarchy (Ancestors)

Dentistry

Central Study Contacts

Yasemin B. ÖNDER, DDS, PhD

CONTACT

+905532502064; ybyilmaz@gmail.com

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: CROSS SECTIONAL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: July 14, 2026
• First Posted: July 22, 2026
• Study Start (Estimated): August 17, 2026
• Primary Completion (Estimated): October 21, 2026
• Study Completion (Estimated): March 17, 2027
• Last Updated: July 22, 2026

Record last verified: 2026-07

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, SAP, ICF, CSR
• Time Frame: Baseline-3 months
• Access Criteria: Access will be granted only to qualified researchers who submit a methodologically sound research proposal. Requests will be reviewed by the principal investigator and study investigators. Approved researchers will receive de-identified individual participant data, the study protocol, statistical analysis plan, and data dictionary after signing a data-sharing agreement. Data will be transferred through secure electronic methods in accordance with institutional policies, applicable regulations, and participant confidentiality requirements.

Locations

TU (1)