Effect of Clinical Crown Lengthening Surgery and Botulinum Toxin A Injection in Gummy Smile Treatment

Study Overview
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Brief Summary
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Background: The demand for beauty is increasing in society as everyone is looking for cosmetic improvement, including gummy smile correction. Object: This study aims to evaluate the efficacy of a combination of a clinical tooth crowns lengthening surgery following by a BTX-A injection in gummy smile treatment upon based on clinical assessment and photography Method: An uncontrolled longitudinal study was implemented at the Faculty of Odonto-Stomatology (FOS) of the University of Medicine and Pharmacy at Ho Chi Minh City (UMPH), Viet Nam, from August 2020 to May 2021. Twenty patients (19 females and one male) at a mean age of 24 years old who came for gummy smile chief complaint were included in the study. Subjects were operated to lengthen the clinical crown following an additional botulinum toxin A injection two months post-surgery. All the participants answered the smile esthetic satisfactory questions and were photographed at the time before treatment (T0), two months after clinical crown lengthening surgery (T1), two weeks (T2), and two months (T3) follow-up visits after BTX-A injection. The gingival exposure (GE) and clinical crown length (CCL) were measured at each time point for analysis.

Official Title
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The Effect of a Combination Between Clinical Crown Lengthening Surgery and Botulinum Toxin A Injection in Gummy Smile Treatment

Conditions
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Gummy Smile

Intervention / Treatment
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* Procedure: Clinical crown lengthening surgery


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Gummy smile because of 2 combined etiologies: Short clinical crown of teeth due to the altered passive tooth eruption Hyperactivity of upper lip muscles (lip mobility level > 8mm) Exclusion Criteria: Pregnant or breastfeeding patients Gummy smiles due to: Maxillary bone overgrowth (maxillary hypertrophy) Vertical maxillary excess Neuromuscular disorder Gingival hyperplasia due to medicine, supplements, or neuromuscular transmission inhibiting agents Systematic diseases that can affect the result of surgical treatment (such as diabetes, heart disease taking blood anticoagulant medicament, blood diseases, immunodeficiency disease etc.) Allergy to BTX-A or albumin History of taking BTX-A injection in the head-neck area formerly Patient with any contraindication of surgery

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Intervention Model: Single Group Assignment
Interventional Model Description: Participants were recruited from patients who came for chief complaint of excess gingival display at the Dental Clinic of the Faculty of Odonto-stomatology, University of medicine and Pharmacy at Ho Chi Minh City. The study population included patients aged from eighteen years with an average length of excessive gingival display ≥ of 4 mm when maximum smiling (counted eight teeth, from the 14 to the 24 teeth) and the height of keratinized gingiva ≥ 3 mm.
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Subjects with gummy smile<br>The study procedure consisted of recruitment, pre&post-operative photography, gingivoplasty, BTX-A injection, recall visits, and data collecting. | Procedure: Clinical crown lengthening surgery<br>* Clinical dental crown lengthening surgery protocol: a clinical crown lengthening surgery was performed. Post-operation protocol Patients were all prescribed antibiotics , anti-inflammation, analgesic, and an antiseptic mouthwash. Patients were instructed for oral hygiene and recalls. Botulinum Toxin A injection One hundred units (U) of botulinum toxin A (BTX-A) were diluted with 2.5ml of sterile saline solution without shaking. 1 mm syringe with a 30-gauge needle was used to get 0.25ml BTX-A for four-point injection, or 0.6ml in case injection of 6 points. Cold compress was applied extraoral 5 mins at injection site before injection. After local anesthesia, the doctor administered slowly 2,5 U of diluted BTX-A at each point until white cellulite appeared. Patients were recalled two weeks (T2), and two months (T3) after injection.<br>* Other names: Botulinum toxin A injection;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Gingival exposure | The outcome is measured in millimeters based on photos of subjects included | At the time before treatment (T0) | 
| Gingival exposure | The outcome is measured in millimeters based on photos of subjects included | Two months after clinical crown lengthening surgery (T1) | 
| Gingival exposure | The outcome is measured in millimeters based on photos of subjects included | Two weeks after Botulinum toxin A injection (T2) | 
| Gingival exposure | The outcome is measured in millimeters based on photos of subjects included | Two months after Botulinum toxin A injection (T2) | 
| Clinical crown length | The clinical crown length is measured in millimeters using digital caliper and periodontal probe | At the time before treatment (T0) | 
| Clinical crown length | The clinical crown length is measured in millimeters using digital caliper and periodontal probe | Two months after clinical crown lengthening surgery (T1) | 
| Clinical crown length | The clinical crown length is measured in millimeters using digital caliper and periodontal probe | Two weeks after Botulinum toxin A injection (T2) | 
| Clinical crown length | The clinical crown length is measured in millimeters using digital caliper and periodontal probe | Two months after Botulinum toxin A injection (T2) | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Gingival exposure, Clinical crown length, clinical crown lengthening surgery, Botulinum toxin A, Gummy smile