Repeated Botulinum Toxin Type A Injections on Intramuscular Fat Accumulation in Individuals With Sleep Bruxism.

NCT ID: NCT07266064

Last Updated: 2025-12-05

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 27 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2024-01-02
• Study Completion Date: 2025-11-20

Brief Summary

This study investigates whether repeated botulinum toxin type A (BoNT-A) injections used to manage sleep bruxism lead to structural changes-specifically intramuscular fat accumulation-in the masseter muscle. Adults with probable sleep bruxism receive BoNT-A injections every six months and undergo ultrasound evaluations before each injection. By tracking fat percentage in the masseter muscle over multiple treatment cycles, the study aims to determine whether long-term BoNT-A use causes progressive structural alterations or remains safe for repeated clinical use.

Detailed Description

Botulinum toxin type A (BoNT-A) is commonly used for the management of sleep bruxism, yet concerns persist regarding its long-term effects on muscle structure, including the possibility of intramuscular fat accumulation in the masseter muscle. This prospective longitudinal study follows adults with probable sleep bruxism who receive bilateral BoNT-A injections at six-month intervals. Ultrasound imaging is performed immediately before each injection, resulting in four injection cycles and five standardized ultrasound assessments.

Intramuscular fat percentage is quantified from B-mode images at rest and during maximum voluntary contraction using binary segmentation techniques. By examining changes over repeated treatment cycles, the study evaluates whether BoNT-A leads to progressive fat infiltration or instead demonstrates a stable or adaptive pattern. Findings will help clarify the structural safety of long-term BoNT-A use in non-spastic masticatory muscles and guide clinical decision-making for ongoing bruxism management.

Conditions

Bruxism; Bruxism, Sleep; Bruxism, Sleep-Related

Study Design

• Allocation Method: NA
• Intervention Model: SINGLE_GROUP
• Primary Study Purpose: SCREENING
• Blinding Strategy: NONE

Study Groups

BoNT-A

At baseline, all participants underwent ultrasonographic evaluation of both masseter muscles (U0). Two weeks later, the first BoNT-A injection was administered bilaterally (U1). Thereafter, ultrasonography was repeated at six-month intervals (U1-U4). Each of the intermediate assessments was followed by a BoNT-A injection two weeks later (U2-U4), whereas the final assessment (U4) was not followed by injection. Thus, the protocol comprised five ultrasound sessions (U0-U4) and four BoNT-A sessions (U1-U4), unless the participant discontinued the study. All ultrasound examinations were performed by the same experienced examiner using the same device and standardized probe settings.

Group Type: EXPERIMENTAL

Botilinum Toxin injection

Intervention Type: OTHER

This prospective longitudinal interventional study included adults with probable sleep bruxism who received bilateral BoNT-A injections every six months, with ultrasonographic assessments also performed at six-month intervals, immediately before each new injection. The protocol therefore comprised four injection cycles and five ultrasound sessions. Ultrasonographic evaluations were conducted before the first injection and six months after each subsequent injection to quantify intramuscular fat percentage at rest and during maximum voluntary contraction. Fat area percentage was computed from standardized B-mode images using binary segmentation in CT-Analyzer software.

Interventions

Botilinum Toxin injection

This prospective longitudinal interventional study included adults with probable sleep bruxism who received bilateral BoNT-A injections every six months, with ultrasonographic assessments also performed at six-month intervals, immediately before each new injection. The protocol therefore comprised four injection cycles and five ultrasound sessions. Ultrasonographic evaluations were conducted before the first injection and six months after each subsequent injection to quantify intramuscular fat percentage at rest and during maximum voluntary contraction. Fat area percentage was computed from standardized B-mode images using binary segmentation in CT-Analyzer software.

Intervention Type: OTHER

Eligibility Criteria

Inclusion Criteria

• Adults aged 18 years or older.
• Clinical diagnosis of probable sleep bruxism according to the international consensus criteria proposed by Lobbezoo et al.
• Indication for BoNT-A injection in the masseter muscle due to bruxism-related pain or muscle hypertrophy.
• Willingness to undergo repeated BoNT-A injections at six-month intervals.
• Willingness to participate in ultrasonographic evaluations at each follow-up visit.

Exclusion Criteria

• Presence of neurological or neuromuscular disorders affecting the masticatory muscles (e.g., dystonia, myasthenia gravis).
• History of orofacial trauma, temporomandibular joint dysfunction, or maxillofacial surgery.
• Systemic diseases that may affect neuromuscular transmission or muscle metabolism.
• Use of medications known to interfere with neuromuscular function, including aminoglycoside antibiotics or corticosteroids.

• Minimum Eligible Age: 18 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

Melek Volkan Yazici

OTHER

Sponsor Role: lead

Responsible Party

Melek Volkan Yazici

Associate Professor

Responsibility Role: SPONSOR_INVESTIGATOR

Principal Investigators

GOKHAN YAZICI, A/Prof

Role: STUDY_CHAIR

Gazi University

Locations

Ankara University, Faculty of Dentistry

Ankara, Cankaya, Turkey (Türkiye)

Countries

Turkey (Türkiye)

Other Identifiers

Botox series

Identifier Type: -

Identifier Source: org_study_id