Clinical Trial Details
— Status: Completed
Administrative data
NCT number |
NCT04820543 |
Other study ID # |
pkussGS2 |
Secondary ID |
|
Status |
Completed |
Phase |
Phase 4
|
First received |
|
Last updated |
|
Start date |
February 20, 2019 |
Est. completion date |
June 20, 2020 |
Study information
Verified date |
March 2021 |
Source |
Peking University |
Contact |
n/a |
Is FDA regulated |
No |
Health authority |
|
Study type |
Interventional
|
Clinical Trial Summary
Botulinum type A (BTX-A) is an easy and efficacious treatment for gingival smile (GS).
However, its dosage and injection sites effect among patients are controversial.The objective
was to compare the reduction of gingival exposure using two methods in patients with
different dosage and injection sites. In this prospective self-controlled study, healthy GS
participates who had an anterior gingival exposure (GE) of more than 3 mm were enrolled and
administered single-point injection of 2 U BTX-A per side in the Simplified Method. And after
8 months, the Individualized Method was administered with 2-5 U BTX-A (total, 4-10 U)
injections into 1-2 points according to the severity presented pretreatment. Data were
collected at baseline and 4, 12, and 32 weeks of follow-up.
Description:
The smile is one of universal facial expressions of the humans. Gingival smile (GS) or gummy
smile defined as any exposure of the gingiva >2 or 3 mm upon smiling, and can substantially
vary from patient to patient, with patients presenting gummy exposures of up to more than 10
mm. The prevalence of GS is 10.57%, and it is more frequently seen in women. Although only an
anatomical variation, it can be considered unattractive and cause significant distress and
impact on one's quality of life. Moreover, most orthodontists and dentists regard GS as an
important risk factors for dental treatment.
GS involves a complex interaction of facial muscles, bones and skin, specifically, it is
related to the hypermobile upper lip (HUL) by the involved muscles and alterations in
anatomical features such as short clinical dental crown, anterior dentoalveolar extrusion,
maxillary excess and short upper lip. Therapies for GS range from botulinum toxin injections
to surgical interventions according to its etiology. Whereas the outcomes of surgical
procedures are long-lasting, botulinum toxin type A (BTX-A) treatment is an easy and fast
outpatient procedure, requiring no downtime and with high efficacy rates. Nevertheless, there
are controversies on the dosage and injection sites of BTX-A, and the efficiency of BTX-A for
GS treatment shows great variation in different studies, with the improvement rate of
gingival exposure (GE) ranging from 62.06% to 98%, Sucupira and Abramovitz advocate the use
of an average amount of BTX-A of 2 U at bilateral levator labii superioris alaeque nasi
muscles(LLSAN) for the treatment of GS, and an average satisfaction level of 9.75 on a
10-point scale was noted in their study. In their article, use of larger dosages and
additional injection sites is discouraged: "Other target muscles described in the literature
do not give any additional benefit to this application and could easily lead to lip ptosis,
inferior lip protrusion, asymmetry, or excessive lengthening of the upper lip." Polo
disagreed their argument. They believe that dosage and injection sites of BTX-A need to be
individualized according to the degree of severity presented. However, no clinical study
compared and verified their divergence, and the highly personal experience and uncertainty
still limit the use of BTX-A for GS treatment. Some authors are of the opinion that injection
with BTX-A is a safe and cosmetically effective treatment for GS only when performed by
experienced practitioners. Other studies preferred to initiate the treatment with
average-dose BTX-A injection to single sites initially, with retouching at a later stage, as
and when required. Based on the lack of studies at the stage of creating the hypothesis for
this study, the investigators compared the efficiency using the simplified method use of 2U
BTX-A of at bilateral LLSAN and the individualized injection of dosage and injection sites
according to the severity of anterior GS presented in patients, and also to assess safety and
patients' satisfaction with the treatment.