Does Botulinum Toxin Injection into Masseter Muscles Affect Subcutaneous Thickness?

Combined Effects of Botulinum Toxin Injection and Oral Appliance Therapy on Lower Facial Contouring: A Randomized Controlled Trial

(1) Background: Botulinum toxin (BoNT) injection is an esthetically effective and safe treatment for contouring the lower face. This study aimed to evaluate the combined effects of BoNT and supplementary oral appliance (OA) therapy on lower facial contouring. (2) Methods: We conducted a prospective randomized controlled trial from January 2015 to June 2016 at the Yonsei University Dental Hospital. Volunteers aged 20−45 years with masseter hypertrophy were randomly assigned to one of two groups: the non-OA group and the OA group. The non-OA group received BoNT injections alone, whereas the OA group received an OA in addition to BoNT injections. Changes in the bulkiest height of the lower face were evaluated by three-dimensional laser scanning before and 4, 8, 12, and 24 weeks after injections in both groups. (3) Results: In both groups, the bulkiest height reductions decreased, with a significant interaction between group (p = 0.046) and time (p < 0.001), although the overall reduction was at a similar level at 24 weeks. (4) Conclusions: The pattern of the bulkiest height reduction of the lower face after BoNT injection differed between standalone treatment and OA therapy, implying a normalizing effect of OA on masseter muscle activity.

Effects of Two Botulinum Toxin Type a Evaluated by Shear Wave Elastography and Electromyographic Measurements of Masseter Reduction

ABSTRACT

The purpose of this study was to evaluate the efficacy and safety of onabotulinumtoxin A and Chinese botulinum toxin type A (CBA) for masseter reduction using elastography and electromyographic measurement. Female subjects aged 21 to 38 years with benign masseter hypertrophy received 1 treatment of either 50 units onabotulinumtoxin A or 50 units CBA in a double-blind clinical trial. The study enrolled 102 subjects (204 sides of masseters); 51 subjects per group. The thickness and stiffness of the masseter muscle and the electromyographic changes were evaluated before and 1, 4, 12, and 24 weeks after injection. One week after injection, the thickness of the masseter muscle did not change significantly, but the stiffness was reduced by 5% to 9%. After 4 weeks of injection, masseter muscle thickness, stiffness and strength decreased significantly compared with before injection. The changes were significantly at 12 weeks. Muscle stiffness measured by Shear-wave elastography was significantly reduced by 20% to 32% in the relaxed state and 25% to 47% in the contractile state. The electromyography showed that masseter muscle strength changed consistently with Shear-wave elastography value before and after injection. Six months after injection, ultrasound and electromyography showed that the masseter muscle thickness and stiffness began to recover. Between the 2 groups, there are no significant difference in thickness, stiffness and muscle strength reduction of masseters after treatment (P > 0.05), as well as in side effects (P > 0.05). Onabotulinumtoxin A and CBA were comparable in the efficacy and safety for masseter reduction.

Botulinum toxin A in dentistry and orofacial surgery: an evidence-based review - part 2: cosmetic applications

Objective An evidence-based review on the role of botulinum toxin type A (BoNTA) on diverse cosmetic applications of interest to dental practitioners and allied specialities. In this context, to identify the cosmetic treatments that have an evidence-based rationale against areas requiring further research, with a view to assess the safety and efficacy of BoNTA.Data source and selection A comprehensive search was conducted using Cochrane Library of Systematic Reviews, Cochrane Central Register of Controlled Trials, and PubMed (Medline) electronic databases. Thirty-nine studies of variable quality were included. The Best Evidence Topics (BETs) Critical Appraisal Tool was used to facilitate the quality assessment of relevant studies.Data extraction Based on current level II evidence, BoNTA was safe and effective to improve facial contour, reduce volume and thickness of bilateral hypertrophic masseter. Conservative doses using a combined approach of BoNTA and hyaluronic acid was recommended as a safe and effective treatment for perioral enhancement supported by level II evidence. There was limited evidence, not higher than level III, to support BoNTA effectiveness for gummy smile associated to perioral musculature hyperactivity, while jawline sculpting targeting the platysma muscle had lower level IV evidence up to this date.Conclusion BoNTA has been widely used off-label for the investigated cosmetic orofacial conditions, with reports of 'good patient and practitioner satisfaction'. However, there is limited high-quality evidence to support the long-term safety and effectiveness of repetitive BoNTA injections. Additionally, no studies were found that provided a cost-effectiveness evaluation of BoNTA formulations against other current cosmetic interventions. Well-designed clinical trials, including long-term follow-up, would help to provide robust evidence-based recommendations for clinical practice, supporting BoNTA popularity, independently or in a combined approach.

Incobotulinum toxin A with a one-year long-lasting effect for trapezius contouring and superior efficacy for the treatment of trapezius myalgia

Context:

Based on various Botulinum toxin A products, reports of the lower efficacy of Incobotulinum toxin A compared with Onabotulinum toxin A for muscle contouring were observed. In addition, complications of trapezius myalgia and shoulder contouring treatment from malpractice have been reported.

Aims:

The study aimed at comparing the efficacy between Incobotulinum toxin A and Onabotulinum toxin A; research was conducted on a safe treatment technique for trapezius hypertrophy and trapezius myalgia.

Materials and Methods:

A split-shoulder, double-blind, randomized controlled trial was performed. Twenty volunteers with trapezius hypertrophy and trapezius myalgia were randomly injected with 30 units of Incobotulinum toxin A and Onabotulinum toxin A in each trapezius muscle guided by ultrasound.

Results:

The trapezius thickness among those receiving treatment with Onabotulinum toxin A and Incobotulinum toxin A on day 60 was 7.35 ± 1.11 and 7.33 ± 1.21 mm, respectively, which did not portray a significant difference (P = 0.991). Compared with the muscle size from day 60 to one year, the size of the trapezius muscle that had been treated by Onabotulinum toxin type A regained a significantly larger size compared with that treated by Incobotulinum toxin A (P = 0.027). On comparing the size of the trapezius muscle treated by Incobotulinum toxin A between one year and day 0, it was observed that the trapezius thickness at one year had significantly decreased (P < 0.001). On comparing the pain score from day 60 to day 0, it was observed that the pain scores of trapezius myalgia treated by Onabotulinum toxin A and Incobotulinum toxin A significantly differed (P = 0.003).

Conclusions:

Incobotulinum toxin A had the same efficacy but a longer lasting effect for the trapezius size contouring and a higher efficacy for trapezius myalgia treatment compared with Onabotulinum toxin A.

Botulinum toxin type A injections for masticatory muscles hypertrophy: A systematic review

The aim of this study is to compare the efficacy of single-point injection of botulinum toxin A versus multi-point operative protocols found in the literature in reducing hypertrophy in patients with masticatory muscle hypertrophy. A systematic review was performed in accordance with the Park et al., 2018 guidelines, selecting articles from PubMed, Google Scholar, Web of Science and Ovid databases up to July 8, 2020.28 studies met the eligibility criteria. 748 patients were treated for masseter hypertrophy (MH) and 4 patients for temporal muscle hypertrophy. As for MH: in 45.2% of cases 3 injection sites (IS) were used, in 18.8% 1 IS, in 16.2% 2 IS, in 13% 5 IS, in 4.1% 6 IS, 2.7% 4 IS. At three months, the mean reduction in masseter muscle thickness is 26-31% when 1 IS was used, 28% in 2 IS, 12-27% in 3 IS and 22-30% in 6 IS. Heterogeneity of results, high bias level and selective reports led to a difficult efficacy comparison of the injection techniques described. Data suggest that the lowest number of IS possible should be used until stronger evidences are presented. Homogeneity in pre- and post-operative protocols is needed to establish a reliable setting for the condition under study.

Efficacy and Safety of a Novel Botulinum Toxin A for Masseter Reduction: A Randomized, Double-Blind, Placebo-Controlled, Optimal Dose-Finding Study

BACKGROUND

A wide lower face and a square jaw are considered esthetic problems, particularly in Asia.

OBJECTIVE

To investigate the optimal dose of a novel botulinum toxin (prabotulinum toxin A) for treating masseteric hypertrophy.

METHODS

Ninety subjects with masseteric hypertrophy were randomly divided into 5 groups and treated with placebo (A, normal saline) or prabotulinum toxin A (B: 24, C: 48, D: 72, and E: 96 units). Photography, ultrasonography, and 3-dimensional imaging were performed before and after injection at baseline and at 4, 8, 12, and 16 weeks after treatment. The participants also rated their satisfaction.

RESULTS

Masseter thickness significantly reduced in all groups at 12 weeks, compared with that in the placebo group. A dose-dependent reduction in masseter thickness was observed at the resting and maximal clenching positions. Sonography and 3-dimensional imaging revealed a gradual reduction in masseter thickness and volume, respectively, during the first 12 weeks. Despite being slightly effective, a dose of 24 units might be insufficient for resolving square face problems. Patients in Group E reported discomfort during jaw movement.

CONCLUSION

Prabotulinum toxin A could effectively improve lower face contour without major complications, with an optimal dose of 48 to 72 units, followed by reinjection after 12 weeks.

Muscle-Bone Crosstalk in the Masticatory System: From Biomechanical to Molecular Interactions

The masticatory system is a complex and highly organized group of structures, including craniofacial bones (maxillae and mandible), muscles, teeth, joints, and neurovascular elements. While the musculoskeletal structures of the head and neck are known to have a different embryonic origin, morphology, biomechanical demands, and biochemical characteristics than the trunk and limbs, their particular molecular basis and cell biology have been much less explored. In the last decade, the concept of muscle-bone crosstalk has emerged, comprising both the loads generated during muscle contraction and a biochemical component through soluble molecules. Bone cells embedded in the mineralized tissue respond to the biomechanical input by releasing molecular factors that impact the homeostasis of the attaching skeletal muscle. In the same way, muscle-derived factors act as soluble signals that modulate the remodeling process of the underlying bones. This concept of muscle-bone crosstalk at a molecular level is particularly interesting in the mandible, due to its tight anatomical relationship with one of the biggest and strongest masticatory muscles, the masseter. However, despite the close physical and physiological interaction of both tissues for proper functioning, this topic has been poorly addressed. Here we present one of the most detailed reviews of the literature to date regarding the biomechanical and biochemical interaction between muscles and bones of the masticatory system, both during development and in physiological or pathological remodeling processes. Evidence related to how masticatory function shapes the craniofacial bones is discussed, and a proposal presented that the masticatory muscles and craniofacial bones serve as secretory tissues. We furthermore discuss our current findings of myokines-release from masseter muscle in physiological conditions, during functional adaptation or pathology, and their putative role as bone-modulators in the craniofacial system. Finally, we address the physiological implications of the crosstalk between muscles and bones in the masticatory system, analyzing pathologies or clinical procedures in which the alteration of one of them affects the homeostasis of the other. Unveiling the mechanisms of muscle-bone crosstalk in the masticatory system opens broad possibilities for understanding and treating temporomandibular disorders, which severely impair the quality of life, with a high cost for diagnosis and management.

Imaging of masseter muscle spasms by ultrasonography: a preliminary study

OBJECTIVES

The aim of this study was to determine the effectiveness of ultrasonography (USG) in locating spasm points in the masseter muscle.

METHODS

Fifteen patients with TMJ dysfunction and five healthy controls were included in the study. First clinical examination of TMJ and palpation of masticatory muscles were done. Then, the masseter muscles were examined by USG. A total of 40 masseter muscles were examined within the study.

RESULTS

Spasm points were observed as limited isoechogenic areas within normal heterogeneous muscle tissue. Within the 30 masseter muscles of patients with TMJ dysfunction, a total of 14 spasm points were detected clinically and 18 spasm points were detected ultrasonographically. No clinic or sonographic spasm point was detected in the masseter muscles of healthy controls.

CONCLUSION

USG demonstrated in detail the internal structure of the masseter muscle in all patients and provided precise localization of the spasm points on the muscle. This is a preliminary study, showing that changes in muscle internal structure can be visualized with USG.

The Expanding Role of Diagnostic Ultrasound in Plastic Surgery

Supplemental Digital Content is available in the text.

Background:

Ultrasound in plastic surgery is quickly finding new applications. Ultrasound surveillance may replace ineffective individual risk stratification and chemoprophylaxis for deep venous thromboses. Abdominal penetration can be a catastrophic complication of liposuction. Preoperative screening for fascial defects may reduce risk. Limiting buttock fat injections to the subcutaneous plane is critical for patient safety, but it is difficult to know one’s injection plane.

Methods:

The author’s use of diagnostic ultrasound was evaluated from May 2017 to May 2018. Ultrasound scans were used routinely to detect deep venous thromboses. Patients undergoing abdominal liposuction and/or abdominoplasty were scanned for possible hernias. Other common applications included the evaluation of breast implants, breast masses, and seroma management. The device was used in surgery in 3 patients to assess the plane of buttock fat injection.

Results:

One thousand ultrasound scans were performed during the 1-year study period. A distal deep venous thrombosis was detected in 2 patients. In both cases, the thrombosis resolved within 1 month, confirmed by follow-up ultrasound scans. A lateral (tangential) fat injection method was shown to safely deposit fat above the gluteus maximus fascia.

Conclusions:

Ultrasound scans are highly accurate, noninvasive, and well-tolerated by patients. Some of these applications are likely to improve patient safety. Early detection of deep venous thromboses is possible. Unnecessary anticoagulation may be avoided. Subclinical abdominal defects may be detected. Ultrasound may be used in the office to evaluate breast implants, masses, and seromas. In surgery, this device confirms the level of buttock fat injection.