Effect of Cross-linked Hyaluronic Acid Filler Versus Botulinum Toxin Type A (Botox) in Management of Gummy Smile

Effect of Cross-linked Hyaluronic Acid Filler Versus Botulinum Toxin Type A (Botox) in Management of Gummy Smile: Randomized Controlled Clinical Trial

A smile is supposed to express one's feelings and expressions, for that there has been an awakening concern for the appearance of gummy smile. Gummy smile is the appearance of about 2mm or more of the gingiva during smiling. It may affect the quality of life of individuals affecting their self-esteem; patients desire to look good not only while resting but while dynamically expressing themselves too. Variable factors contribute to this gingival display whether skeletal, dental or muscular. Variable treatment modalities are done solely or in adjunction to each other for the treatment of gummy smile including both surgical or nonsurgical procedures.

Study Overview

• Status: Not yet recruiting
• Conditions: Gummy Smile Due to Hypermobile Upper Lip
• Intervention / Treatment: Procedure: Injection of cross linked hyaluronic acid filler

Detailed Description

In patients not preferring surgical correction of gummy smile, botulinum toxin injection type A can be a helpful solution for reduction of peri-oral muscular hypermobility. A characteristic feature of botulinum toxin is the need for the re-injection in short intervals of time to yield better lasting effects. The use of cross-linked hyaluronic acid dermal fillers when used to myomodulate the peri-oral muscles give more immediate results and reduces the need for re-injection at shorter intervals.

Botulinum toxin type A, a toxin produced by the bacteria Clostridium botulinum, has been widely used in different therapeutic and cosmetic applications in dentistry. Amongst its important applications is the treatment of gummy smile by reducing the hypermobility of the peri-oral muscles through chemical denervation. Botox elicits temporary results and requires re-injection at certain time points. It is a safe, suitable, transient solution for patients not willing to undergo any surgical intervention to manage their gummy smile. Another approach for the non invasive treatment of muscular hypermobility is the injection of cross linked hyaluronic acid filler. Once the filler is injected, it typically occupies space that lessens the muscle movement limiting its hypermobility. Instant Smile enhancement is observed upon injection of cross-linked hyaluronic acid fillers and no need to repeat the injection at closer periods of time. Hyaluronic acid fillers are non-permanent fillers that are degradable by hyaluronidase and cross linking renders them more resistant to enzymatic degradation thus lasting longer.

• Study Type: Interventional
• Enrollment (Estimated): 34
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Raghda Hussein; Phone Number: 01122642622; Email: raghda.metwaly@dentistry.cu.edu.eg

Study Locations

• Egypt
  • Cairo, Egypt, 00200
    • CairoU
  • Giza, Egypt, 12613
    • Cairo University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Patients with excessive gingival display ranging from 3-8mm due to hypermobile lip.
• Age ranges from 18 years or above.

Exclusion Criteria:

• Excessive gingival display due to other etiological factors.
• Patients allergic to botox or hyaluronic acid fillers.
• Patients with any medical condition that contraindicates botox or hyaluronic acid filler injection.
• Patients previously injected with permanent fillers.
• Pregnancy.
• Breastfeeding females.
• Patients with active inflammatory or infectious disease at intended site of injection.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Triple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Group I will receive botulinum toxin type A injection.; Injection site will be determined at a point in which the elevator muscles of the upper lip which are levator labii superioris, levator labii superioris alaeque nasi, and zygomaticus minor converge into the lateral area of the ala of the nose. The center of intersection of the mentioned muscles is termed Yonsei Point and estimated to be at a 1cm horizontal distance from the ala of the nose and a 3cm vertical distance from the lip line. Lidocaine 5% ointment will be applied to the intended injection site for 20 mins. In control group, 2.5 units of botulinum toxin will be injected bilaterally at Yonsei Point. An insulin needle will be used for injecting the botox.	Procedure: Injection of cross linked hyaluronic acid filler; Injection of cross linked hyaluronic acid filler
Experimental: Group II will receive cross linked hyaluronic acid filler injection; Lidocaine 5% ointment will be applied to the intended injection site for 20 mins. In intervention group, a bolus of 0.2 ml of 20% cross linked hyaluronic acid filler will be injected in canine fossa region using a 29G needle preceeded by aspiration for 10 seconds ensuring no blood vessel will be involved.	Procedure: Injection of cross linked hyaluronic acid filler; Injection of cross linked hyaluronic acid filler

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Gingival display	will be measured from a point denoting the lowest margin of the upper lip perpendicular and superior to the midportion of the gingival margin of the maxillary lateral incisor to the gingival margin at the midpoint of the maxillary lateral incisor. The midpoint of the incisal edge of the maxillary lateral incisor will be used as a reference point if the upper lip fell below the gingival margin of the same tooth post-injection (Diaspro, Cavallini et al. 2018).	week 2, month 1, month 3, month 6, month 9

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Patient satisfaction	The patient will be asked to rate the satisfaction about her/his smile on a scale from 1 to 5 where 1 represents the least satisfied and 5 indicates the most (Makkeiah, Harfoush et al. 2021).	week 2, month 1, month 3, month 6, month 9
Postoperative pain	The patient will be asked to mark her/his current level of pain on a scale of 10 cm line denoting a range between zero being (no pain) to 10 (maximum pain) (Diaspro, Cavallini et al. 2018).	week 2, month 1, month 3, month 6, month 9
Lip mobility	will be measured by subtracting upper lip length during smiling from upper lip length at rest (Sabbah 2022). The upper lip length is measured from the subnasale to the lower border of the upper lip at the central incisors' region at smile and rest (Ali, Kilani et al. 2023).	week 2, month 1, month 3, month 6, month 9

Collaborators and Investigators

• Sponsor: Cairo University

Study record dates

Study Major Dates

• Study Start (Estimated): December 1, 2025
• Primary Completion (Estimated): December 1, 2025
• Study Completion (Estimated): December 1, 2025

Study Registration Dates

• First Submitted: April 15, 2025
• First Submitted That Met QC Criteria: April 29, 2025
• First Posted (Actual): April 30, 2025

Study Record Updates

• Last Update Posted (Actual): April 30, 2025
• Last Update Submitted That Met QC Criteria: April 29, 2025
• Last Verified: April 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Immunologic Factors; Physiological Effects of Drugs; Protective Agents; Adjuvants, Immunologic; Viscosupplements; Hyaluronic Acid
• Other Study ID Numbers: 5699269

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No