Effects of Dose and Injection Site on Gingival Smile Treatment with Botulinum Toxin Type A: A Prospective Study.

Abstract

he smile is one of the universal facial expressions of humans. Gingival smile is characterized by gingival exposure of greater than 3 mm when smiling. The degree of gingival exposure can vary substantially between patients, with patients presenting gingival exposure of up to more than 10 mm. 1,2 The prevalence of gingival smile is 10.57%, 3 and it is more frequently observed in female patients. 4,5 Although gingival smile is merely an anatomical variation, it can be considered unattractive, causing significant distress and impacting one's quality of life. 6 Moreover, most orthodontists and dentists regard gingival smile as an important risk factor for dental treatment. 7 Gingival smile involves a complex interaction between the facial muscles, bone, and skin; specifically, it is related to hypermobility of the upper lip with muscle involvement and alterations in anatomical features, such as a short clinical dental crown, anterior dentoalveolar extrusion, maxillary

Botulinum Toxin A for Gummy Smile—Keep It Simple

“…Next, the authors concluded that increasing the number of injection points (in G1 vs G2) did not improve the clinical result but did increase the longevity of the clinical effect of botulinum toxin on EGD. This was in line with Nasr et al's conclusions from a recent systematic review, 3 which is not too dissimilar from a recent study by Gong et al 4 Interestingly, Gong et al also compared 2 injection points similar to those in the current study, at the LLSAN and Yonsei point. Although the authors should be commended on their efforts to perform electromyography (EMG) as a means to evaluate the perioral musculature after treatment of EGD with botulinum toxin, as they have alluded to themselves, however, “EMG captures the electrical activity of a region and not only of the LLSAN and LLS muscles, which might be the case here,” 1 and this can be seen in Table 4, where the results are difficult to interpret (for instance, was the increase from 125 to 169 Aa at Week 16 due to a different operator, since it went back down to 125 at Week 21?…”

A Systematic Review and Meta-Analysis Comparing Surgical and Nonsurgical Treatments for Excessive Gingival Display

“…The initial severity of gingival exposure and the treatment modality played a role in the treatment effects. Gong et al (2023) categorized the pre-treatment gingival show into three groups based on severity: mild (3–5 mm), moderate (5–7 mm), and severe (greater than 7 mm) [ 39 ]. In this meta-analysis, the studies were divided into three groups based the range of initial EGD: mild (2–3.99 mm), moderate (4–5.99 mm), and severe (6 mm or more).…”

“…The nonsurgical studies included BTX injection and orthodontic intrusion. The studies were further subdivided into three groups based the range of initial EGD: mild (2–3.99 mm), moderate (4–5.99 mm), and severe (6 mm or more) [ 3 , 39 , 40 , 41 ]. The post-treatment changes in gingival display at four time points (1, 3, 6, and 12 months) were calculated, pooled by using a random-effects model, and expressed as mean difference with a 95% confidence interval (CI) using a single-cohort meta-analysis.…”

“…At 6 months post-treatment, nonsurgical treatments reported a mean reduction of 0.51 mm (95% CI: 0.23-0.79 mm) in gingival display, whereas surgical treatments reported an average reduction of 2.86 mm (95% CI: 2.06-3.65 mm) (Figure 4). [5,11,15,39,40,46,[48][49][50][52][53][54][55][56][57]59].…”

Application of botulinum toxin at the Yonsei point for the treatment of gummy smile: A randomized controlled trial

“…1,11,12,18,35,36 According to our recent findings, 3 U per side is suitable for a gummy smile with the anterior GE less than 5 mm, but is not sufficient for GE of 5 mm or greater. 37 Thus, further research will be designed to explore injection doses for more appropriate treatment for gummy smile.…”