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Completed

NCT Number: NCT07673471

Vertical Facial Morphology and Occlusal Force Changes After Masseter Botulinum Toxin Injection in Bruxism

This study investigated whether the shape of the face affects how jaw muscles respond to botulinum toxin injections in people who grind their teeth (bruxism). Participants were divided into two groups based on their facial structure: low-angle (shorter face height) and normal-angle. Each participant received botulinum toxin type A injections into the masseter (jaw) muscle. Bite force measurements were taken before and 15 days after the injection using the T-Scan computerized occlusal analysis system. The study aimed to determine whether facial structure influences the early changes in bite force balance following the injection.

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Key information

Conditions

Bruxism Behavior Habits Occlusal Changes Stomatognathic Diseases Tooth Diseases

Age range

18 year–40 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Department of Orthodontics, Faculty of Dentistry, Biruni University

Istanbul, 34010, Turkey (Türkiye)

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Age 18-40 years
  • Confirmed bruxism diagnosis through self-report and clinical signs
  • Full permanent dentition excluding third molars
  • Angle Class I molar relationship
  • No previous BTX-A injection within 6 months
  • GoGn/SN angle between 18° and 38° on lateral cephalometric radiograph

Exclusion criteria

  • Systemic neuromuscular disorders
  • Known allergy to botulinum toxin or its excipients
  • Pregnancy or breastfeeding
  • Active infection at the injection site
  • Concurrent use of medications known to interact with BTX-A
  • History of orthognathic surgery or prior temporomandibular joint surgery

Treatment and study plan

Botulinum Toxin Type A (BOTOX) Injection

Biological

Botulinum toxin type A (Botox®, Allergan, Irvine, CA, USA) was injected bilaterally into the masseter muscle at a dose of 25 units per side (50 units total per patient). Injections were performed by a single experienced clinician under sterile conditions using a 30-gauge needle.

Other names: botox

Primary outcomes

  1. Change in Center of Force (CoF)

    Time frame: Baseline (T0) and day 15 post-injection (T1)

    The Center of Force (CoF) represents the geometric center of the total occlusal force distribution, measured using the T-Scan Novus™ computerized occlusal analysis system (version 10.0.40; Tekscan, Inc., South Boston, MA, USA). CoF values closer to zero indicate greater bilateral occlusal balance. Within-group changes (T0 to T1) and between-group differences were assessed and compared between low-angle (GoGn/SN < 26°) and normal-angle (GoGn/SN 26-38°) subgroups.

Secondary outcomes

  1. Change in Anterior and Posterior Force Percentage

    Time frame: Baseline (T0) and day 15 post-injection (T1)

    Anterior force percentage is defined as the combined occlusal force distribution of the anterior teeth, and posterior force percentage as the combined force distribution of the posterior teeth. Both were measured using the T-Scan Novus™ system at baseline (T0) and day 15 post-injection (T1). Within-group changes and between-group differences in anterior-posterior force distribution were evaluated and compared between low-angle and normal-angle subgroups.

Sponsors and collaborators

Lead sponsor

Biruni University

Other

Registry information

Official study title

Influence of Vertical Facial Morphology on Occlusal Force Changes After Masseter Botulinum Toxin Injection in Bruxism: A Prospective T-Scan Study

Important dates

Study start
2026
Primary completion
2026
Study completion
2026
First posted
Jun 29, 2026
Registry last updated
Jun 29, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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