Botulinum Toxin Type A Versus Cross-Linked Hyaluronic Acid Filler Myomodulation for Non-Surgical Management of Excessive Gingival Display

NCT07715331 | Completed

• 1 other identifier: P-ME-25-02
• Study Type: interventional
• Target: 20
• Locations: 1 country
• Sites: 1

Brief Summary

This randomized controlled trial compared the clinical efficacy and patient satisfaction of two non-surgical treatments for excessive gingival display (gummy smile): botulinum toxin type A (BTX-A) and cross-linked hyaluronic acid (HA) filler myomodulation. Excessive gingival display is defined as exposure of 3 mm or more of gingival tissue during maximal smiling. It affects approximately 14% of women and 7% of men and is associated with reduced self-confidence, smile suppression in social settings, and impaired quality of life. When caused by hyperactivity of the upper lip elevator muscles, it can be treated without surgery using injectable therapies. Twenty patients (18 females, 2 males; age 18-45 years) with excessive gingival display greater than 3 mm were randomly allocated 1:1 to one of two groups. Group A (n=10) received bilateral injections of botulinum toxin type A (Refinex; 5 IU per side) at the Yonsei point. Group B (n=10) received cross-linked hyaluronic acid filler (Juvederm Voluma with lidocaine; 1.0 mL total) injected at six periosteal sites around the nose and upper lip using a myomodulation technique. Participants were assessed at baseline and at 1, 3, and 6 months after treatment. The primary outcome was maximum gingival display measured in millimeters using a calibrated periodontal probe. Secondary outcomes included patient satisfaction measured by Visual Analog Scale and a 12-item questionnaire, and adverse event monitoring. Both treatments produced equivalent gingival display reductions at one month (BTX-A: 69.6%; HA: 63.0%). At six months, the HA group maintained a statistically significant 26.4% improvement while the BTX-A group showed near-complete relapse. Despite this, BTX-A patients reported higher categorical satisfaction. Both treatments had excellent safety profiles.

Conditions

Excessive Gingival Display; Gingival Diseases; Gummy Smile; Esthetics, Dental

Outcome Measures

Primary Outcomes (1)

• Maximum Gingival Display

  Maximum gingival display (mm) measured from the lower border of the upper lip to the free gingival margin at the right central incisor during standardised maximal smiling, using a UNC-15 periodontal probe. Three consecutive measurements taken and averaged by the same operator.

  Baseline (T0), 1 month (T1), 3 months (T2), 6 months (T3) post-treatment

Secondary Outcomes (4)

• Overall Smile Satisfaction

  Baseline (T0) and 6 months (T3) post-treatment

• Gingival Display Satisfaction

  Baseline (T0) and 6 months (T3) post-treatment

• Psychosocial Impact and Treatment Satisfaction

  Baseline (T0) and 6 months (T3) post-treatment

• Adverse Events

  1 month (T1), 3 months (T2), and 6 months (T3) post-treatment

Study Arms (2)

BTX-A Group

ACTIVE COMPARATOR

Participants received bilateral injections of botulinum toxin type A (Refinex®; 5 IU per side) at the Yonsei point - the anatomical convergence of the levator labii superioris alaeque nasi (LLSAN), levator labii superioris (LLS), and zygomaticus minor muscles - using an insulin syringe with a 30-gauge needle. Total dose: 10 IU.

Drug: Botulinum Toxin Type A (Refinex®)

HA Myomodulation Group

ACTIVE COMPARATOR

Participants received cross-linked hyaluronic acid filler (Juvéderm Voluma® with lidocaine; 20 mg/mL; VYCROSS technology) administered as five periosteal deposits of 0.2 mL each (total 1.0 mL) at: piriform fossa and anterior nasal spine bilaterally, and base of nose, using a 27-gauge needle. Negative aspiration confirmed before each injection.

Drug: Cross-Linked Hyaluronic Acid Filler (Juvéderm Voluma® with Lidocaine)

Interventions

Cross-Linked Hyaluronic Acid Filler (Juvéderm Voluma® with Lidocaine) DRUG

20 mg/mL cross-linked HA, total 1.0 mL per patient, five periosteal injection sites; VYCROSS technology

HA Myomodulation Group

Botulinum Toxin Type A (Refinex®) DRUG

5 International Units per side, bilateral injection at Yonsei point, single-session treatment

BTX-A Group

Eligibility Criteria

• Age: 18 Years - 45 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64)

You may qualify if:

• Excessive gingival display \>3 mm during maximal smiling (measured by UNC-15 periodontal probe)
• Age 18-45 years
• Either sex
• Ability to provide written informed consent
• Availability for all follow-up visits at 1, 3, and 6 months post-treatment

You may not qualify if:

• Chronic neurological diseases or blood coagulation disorders
• Pregnancy or lactation
• Immunological disease or current immunosuppressive drug therapy
• Known sensitivity or allergy to botulinum toxin or hyaluronic acid products
• Previous treatment for gummy smile within 12 months
• Extreme age (outside 18-45 range) or pediatric patients

Sponsors & Collaborators

• Al-Azhar University: lead

Study Sites (1)

Faculty of Dental Medicine for Girls, Al-Azhar University

Cairo, Cairo Governorate, Egypt

Location

MeSH Terms

Conditions

Gingival Diseases

Interventions

Botulinum Toxins, Type A; Lidocaine

Condition Hierarchy (Ancestors)

Periodontal Diseases; Mouth Diseases; Stomatognathic Diseases

Intervention Hierarchy (Ancestors)

Botulinum Toxins; Metalloendopeptidases; Endopeptidases; Peptide Hydrolases; Hydrolases; Enzymes; Enzymes and Coenzymes; Metalloproteases; Bacterial Proteins; Proteins; Amino Acids, Peptides, and Proteins; Bacterial Toxins; Toxins, Biological; Biological Factors; Acetanilides; Anilides; Amides; Organic Chemicals; Aniline Compounds; Amines

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Principal Investigator

Study Record Dates

• First Submitted: July 15, 2026
• First Posted: July 20, 2026
• Study Start: January 1, 2025
• Primary Completion: February 28, 2026
• Study Completion: February 28, 2026
• Last Updated: July 21, 2026

Record last verified: 2026-07

Data Sharing

• IPD Sharing: Will not share

Locations

EG (1)