Clinical Trial Details
— Status: Completed
Administrative data
| NCT number |
NCT04527744 |
| Other study ID # |
pkussyonseipoint |
| Secondary ID |
|
| Status |
Completed |
| Phase |
N/A
|
| First received |
|
| Last updated |
|
| Start date |
October 17, 2020 |
| Est. completion date |
October 17, 2021 |
Study information
| Verified date |
November 2021 |
| Source |
Peking University |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Interventional
|
Clinical Trial Summary
The purpose of the present study will be to evaluate the efficacy of a single dose of
botulinum toxin (BTX) at the Yonsei point for the treatment of gummy smile (GS).
In this double-blind single-site randomized clinical trial, A total number of 36 patients
with gummy smile will be enrolled in the study at Peking University School and Hospital of
Stomatology over a period of 12 months. Patients will be included and randomized 1:1 to two
groups for BTX-A treatment at different injection point. For experimental group, Three units
of onabotulinumtoxinA (BTX-A) per site (90 hemifaces) will be initially injected at the
Yonsei point. For control group，the same dose of BTX will be injected into the levator labii
superioris alaeque nasi muscle, and the injection point is located 3 to 5 mm lateral to each
nostril, which was a classical injection point of this treatment. The patients will be then
assessed at 2, 4, 12, 36 and 72 weeks postinjection. All subjects underwent standardized
measurements by a single examiner, including dynamic and static measurements and a lateral
cephalometric radiograph. In addition, facial photos and videos and a questionnaire of
self-assessment will be obtained. The primary outcome measurement is the anterior gingival
exposure measurements when the subject get an achieve full, unrestricted, spontaneous smiles
2 weeks postinjection.
Description:
BACKGROUND:
Gummy smile (GS), also known as excessive gingival display, is a common unaesthetic clinical
condition. Recent evidence showed that botulinum type A (BTX-A) injection is a promising,
simple, corrective method for GS. However, Currently, there is no standardized approach for
the treatment of excessive gingival exposure with botulinum toxin, and controversies still
exist and due to different injection methods, the efficiency of BTX-A for GS treatment shows
great variation in different studies, with the improvement rate of gingival exposure (GE)
ranging from 62% to 98%.
The treatment goal is to identify a consistent, minimally invasive alternative for the
correction of GS caused by hyperfunctional upper lip elevator muscles. In 2009, Hwang et. al.
described the Yonsei point, which is the confluence of three muscles - the levator labii
superioris (LLS), the levator labii superioris alaeque nasi (LLSAN), and the zygomaticus
minor (Zm). These three muscles are primarily responsible for the smile.
In order to minimize the complications associated with multiple injections of BTX, the
present study is designed with the prime purpose of evaluating the efficacy of one injection
of BTX at the Yonsei point as a minimally invasive approach in the treatment of GS.
In this double-blind single-site randomized clinical trial, A total number of 36 patients
with gummy smile will be enrolled in the study at Peking University School and Hospital of
Stomatology over a period of 12 months. Patients will be included and randomized 1:1 to two
groups for BTX-A treatment at different injection point. For experimental group, Three units
of onabotulinumtoxinA (BTX-A) per site (90 hemifaces) will be initially injected at the
Yonsei point. For control group，the same dose of BTX will be injected into the levator labii
superioris alaeque nasi muscle, and the injection point is located 3 to 5 mm lateral to each
nostril, which was a classical injection point of this treatment. The patients will be then
assessed at 2, 4, 12, 36 and 72 weeks postinjection.
The primary outcome measurement is the anterior gingival exposure measurements when the
subject get an achieve full, unrestricted, spontaneous smiles 2 weeks postinjection.
METHODS
1. Study Design and Participants This double-blind single-site randomized clinical trial
will be conducted in Peking University School and Hospital of Stomatology from October
of 2020 to 2021, approved by the Institutional Review Board of the Peking University
Health Science Center (No: 202056097) and conducted in accordance with the tenets of the
Declaration of Helsinki.
A total number of 36 patients with gummy smile will be enrolled in the study. The
inclusion criteria will be as follows: ≥3.0-mm GE upon unrestricted, "full-blown"
smiling and age between 18 and 60 years. The exclusion criteria will be contraindication
of BTX-A, previous diseases or treatments affecting the position of the gingiva or upper
lips, history of BTX-A injections to the head or neck region, facial paralysis, and/or
subject's refusal to participate.
2. Preintervention measurements Before injection, all subjects underwent standardized
measurements by a single examiner, including dynamic and static measurement. In
addition, facial photos and videos and a questionnaire of self-assessment will be
obtained.
2.1 Dynamic measurements Extremely funny jokes, statements, singing, and/or dancing will
be played out to the subjects to achieve full, unrestricted, spontaneous smiles as
described by Sarver and Ackerman.7 The measurements will be taken individually during 3
different spontaneous smiles to ensure maximal smile for each measured area. Dynamic
measurements included anterior GE, bilateral posterior GEs, bilateral distance from
commissures to the dental midline, and bilateral vertical positions of commissures.
Anterior GE presented the severity of GS as the primary indicator.
2.2 Static measurements The following measurements will be performed with the patient in
a relaxed state (resting jaw position). Lip-teeth relationship included the exposed
medial incisor (the distance between the inferior margin point of the right incisor and
the lower margin of the upper lip) and the upper lip length. Dental factors included the
upper right incisor length, width-to-length ratio of the upper medial incisor, and the
overbite and overjet of the anterior teeth.
3. Interventions Patients will be included and randomized 1:1 to two groups for BTX-A
treatment at different injection point. For all patients, Lyophilized 100 U of BTX-A
(Botox, Allergan, Irvine, CA) will be reconstituted in 2.5 mL of 0.9% sodium chloride
solution.21 A uniform BTX-A injection technique22 with single-site injection will be
administered by the same doctor. For experimental group, Three units of
onabotulinumtoxinA (BTX-A) per site (90 hemifaces) will be initially injected at the
Yonsei point. For control group，the same dose of BTX will be injected into the levator
labii superioris alaeque nasi muscle, and the injection point is located 3 to 5 mm
lateral to each nostril. No anesthesia will be given during the procedure.
4. Follow-up The patients will be then assessed at 2, 4, 12, 36 and 72 weeks postinjection.
All dynamic measurements; some static measurements (exposed medial incisor, upper lip
length, and medial incisor length); and facial photos and videos will be repeated.
Questionnaires will be provided to patients to determine patient satisfaction, side
effects, willingness to undergo a repeat treatment, and an improvement in their
nasolabial fold.
5. Statistical analysis Data entry will be managed using EpiData 3.1 (EpiData Association,
Denmark) and accuracy will be ensured by double entry and validation. The normality of
numerical variables will be assessed using a Shapiro-Wilk test. The mean and standard
deviation will be used to describe normally distributed numerical values, and an
independent-samples t test will be used to compare the 2 groups. Non-normally
distributed numerical values will be described using the median and interquartile range
(25th percentile, 75th percentile). The difference between the 2 groups will be compared
using a Mann-Whitney U test. For categorical variables, the fraction of the treatment
group that belonged to the given category will be used, and the difference between the 2
groups will be compared using a x2 test (Fisher exact probability method). All
statistical analyses will be carried out using SPSS(Statistical Product and Service
Solutions) software v. 20.0 (IBM Corp. Armonk, NY). A 2-tailed P value less than .05
will be considered to indicate a statistically significant difference. Data will be
analyzed by the Research Center of Clinical Epidemiology (Peking University, Beijing,
China).
