Masseteric Hypertrophy Research Articles

A comparative study of the efficacy and safety of radiofrequency ablation and botulinum toxin A in treating masseteric hypertrophy

The aim of the present study was to evaluate the effects of two treatments for masseteric hypertrophy. In total, 24 patients with masseteric hypertrophy were enrolled in this study. Patients were randomly divided into two groups: 12 individuals were treated with radiofrequency (RF) ablation and 12 patients received an injection of botulinum toxin A. The thickness of the masseter muscle under tension was measured using ultrasound and clinical photographs were captured prior to treatment and at 6 and 12 months following treatment. Complications were observed during 12-month follow-up. In the group injected with botulinum toxin A, masseteric muscle thickness decreased to the lowest point 6 months after the injections but increased until 12 months after injection. However, in the group treated with RF ablation, muscle thickness decreased steadily over the 12 months following surgery. Therefore, the results of the present study indicated that the effect of RF ablation on the thickness of the masseter muscle may be much larger than that obtained following injection with botulinum toxin A.

Book Review: Cosmetic Injection Techniques: A Text and Video Guide to Neurotoxins and Fillers

Theda C. Kontis, Victor G. Lacombe Cosmetic Injection Techniques: A Text and Video Guide to Neurotoxins and Fillers. Stuttgart, Germany: Thieme, 2013. ISBN-10: 1604067128 Cosmetic Injection Techniques: A Text and Video Guide to Neurotoxins and Fillers is a comprehensive and detailed book that describes locations/techniques for the injection of fillers and neurotoxins. Its concise descriptions of these techniques, along with excellent videos and high-quality original artwork, make this one of the best cosmetic surgery textbooks of the past 25 years. Designed to assist both beginners and advanced cosmetic physicians and practitioners with filler and neurotoxin injection techniques, this book is divided by injection location and indication (eg, sunken cheeks, tear trough deformity, acne scars, sweating of the feet, and masseter hypertrophy). Fifty-nine injection techniques are listed in the table of contents—this number includes an overview and sections on preparation, instrumentation, and collaboration of societies—and each is accompanied by a video. …

B OTOX : Broadening the Horizon of Dentistry

Botox has been primarily used in cosmetic treatment for lines and wrinkles on the face, but the botulinum toxin that Botox is derived from has a long history of medically therapeutic uses. For nearly 13 years, until the introduction of Botox Cosmetic in 2002, the only FDA-approved uses of Botox were for crossed eyes (strabismus) and abnormal muscle spasms of the eyelids (blepharospasm). Since then botulinum A, and the seven other forms of the botulinum toxin, have been continuously researched and tested. Botox is a neurotoxin derived from bacterium clostridium botulinm. The toxin inhibits the release of acetylcholine (ACH), a neurotransmitter responsible for the activation of muscle contraction and glandular secretion, and its administration results in reduction of tone in the injected muscle. The use of Botox is a minimally invasive procedure and is showing quite promising results in management of muscle-generated dental diseases like Temporomandibular disorders, bruxism, clenching, masseter hypertrophy and used to treat functional or esthetic dental conditions like deep nasolabial folds, radial lip lines, high lip line and black triangles between teeth.

Change of Distribution and Timing of Bite Force after Botulinum Toxin Type A Injection Evaluated by a Computerized Occlusion Analysis System

PurposeThe aim of this study was to determine the force distribution and pattern of mastication after injection of botulinum toxin type A (BTX-A) into both masseter muscles. The hypothesis to be tested was that the difference between right and left balance of occlusal force diminishes over time following BTX-A injection.Materials and MethodsFifteen patients were submitted to BTX-A injection therapy for subjective masseter hypertrophy. A total of 25 U of BTX-A (50 U in total) was injected into two points located 1 cm apart at the center of the lower one-third of both masseter muscles. All patients were examined using the T-Scan occlusion analysis system before and 4, 8, 12, and 24 weeks after BTX-A injection.ResultsA significant change in force balance was found between the right and left sides over time and the difference between the two sides decreased with the time post-injection, reaching a minimum at 12 weeks. Comparison of the force balance between the anterior and posterior occlusions revealed no significant difference at any of the time points. The occlusion and disclusion times (right and left sides) did not differ significantly with time since BTX-A injection.ConclusionA decline in the difference in the clenching force between the left and right sides was found with increasing time up to 12 weeks following BTX-A injection.

Consensus Recommendations on the Aesthetic Usage of Botulinum Toxin Type A in Asians

The use of botulinum toxin has rapidly expanded into various aesthetic applications. Any guideline representing a consensus for aesthetic treatments using botulinum toxin type A (BTA) in Asians has not been published. To provide consensus recommendations on common aesthetic problems which are treated by neurotoxin in Asians. A panel of experienced Korean dermatologists was convened to develop a clinical consensus on common aesthetic problems involving the face, neck, and calves in Asians, based on their own extensive experience. The consensus recommendations address general questions regarding treatment and provide specific guidelines on each common aesthetic indication. The recommended final concentration of BTA was 50U/mL after reconstitution with physiologic saline. For horizontal forehead lines, the members recommended nine injections in two rows into the frontalis with 1U/point. For glabellar lines, the members recommended three injection points (a total of 8U). For crow's feet, the members recommended three injections per side (7U/side) at the lateral part of the orbicularis oculi. For infraorbital wrinkles, one to two points per side in the superficial subcutaneous space approximately 1cm below the lash line were recommended (1-2U/side). For nasal flare, one injection point in the middle of each ala nasi was recommended (a total of 2U). For depressed nasal tip, a single injection deep within the columella was recommended, with a dose of 3U. For benign masseter hypertrophy, the members recommended a six-point injection to the masseter (three points per side for a total of 50-60U). For the treatment of calf hypertrophy, the members recommended a total dose of 100 to 120U (50-60U/side), divided between six injection points (approximately 8-10U/point). This guideline provides a framework for physicians who wish to perform safe and efficacious injections of BTA in Asians.

Botulinum toxin for masseter hypertrophy

Benign masseter muscle hypertrophy is an uncommon clinical phenomenon of uncertain aetiology which is characterised by a soft swelling near the angle of the mandible. The swelling may on occasion be associated with facial pain and can be prominent enough to be considered cosmetically disfiguring. Varying degrees of success have been reported for some of the treatment options for masseter hypertrophy, which range from simple pharmacotherapy to more invasive surgical reduction. Injection of botulinum toxin type A into the masseter muscle is generally considered a less invasive modality and has been advocated for cosmetic sculpting of the lower face. Botulinum toxin type A is a powerful neurotoxin which is produced by the anaerobic organism Clostridium botulinum and when injected into a muscle causes interference with the neurotransmitter mechanism producing selective paralysis and subsequent atrophy of the muscle.This review is an update of a previously published Cochrane review. To assess the efficacy and safety of botulinum toxin type A compared to placebo or no treatment, for the management of benign bilateral masseter hypertrophy. We searched the following databases from inception to April 2013: the Cochrane Central Register of Controlled Trials (CENTRAL); MEDLINE (via PubMed); EMBASE (via embase.com); Web of Science; CINAHL; Academic Search Premier (via EBSCOhost); ScienceDirect; LILACS (via BIREME); PubMed Central and Google Scholar (from 1700 to 19 April 2013). We searched two bibliographic databases of regional journals (IndMED and Iranmedex) which were expected to contain relevant trials. We also searched reference lists of relevant articles and contacted investigators to identify additional published and unpublished studies. Randomised controlled trials (RCTs) and controlled clinical trials (CCTs) comparing intra-masseteric injections of botulinum toxin versus placebo administered for cosmetic facial sculpting in individuals of any age with bilateral benign masseter hypertrophy, which had been self-evaluated and confirmed by clinical and radiological examination were considered for inclusion. We excluded participants with unilateral or compensatory contralateral masseter hypertrophy resulting from head and neck radiotherapy. Two review authors independently screened the search results. For future updates, two authors will independently extract data and assess trial quality using the Cochrane risk of bias tool. Risk ratios (RR) and corresponding 95% confidence intervals (CI) will be calculated for all dichotomous outcomes and the mean difference (MD) and 95% CI will be calculated for continuous outcomes. We retrieved 683 unique references to studies. After screening these references 660 were excluded for being non-applicable. We assessed 23 full text articles for eligibility and all of these studies were excluded from the review. We were unable to identify any RCTs or CCTs assessing the efficacy and safety of intra-masseteric injections of botulinum toxin for people with bilateral benign masseter hypertrophy. The absence of high level evidence for the effectiveness of this intervention emphasises the need for well-designed, adequately powered RCTs.

RimabotulinumtoxinB versus OnabotulinumtoxinA in the Treatment of Masseter Hypertrophy: A 24-Week Double-Blind Randomized Split-Face Study

Background: Masseter hypertrophy can be ameliorated by botulinum toxin. Objective: To compare the efficacy and safety of RimabotulinumtoxinB (BTX-B) and OnabotulinumtoxinA (BTX-A) in the treatment of masseter hypertrophy. Methods: Sixteen women with bilateral masseter hypertrophy received single injections of BTX-A or BTX-B at a dose ratio of 1:50 or 1:70 in a 24-week double-blind randomized split-face study. Results: Both BTX-A and BTX-B produced significant improvements in masseter hypertrophy. The maximum volume reduction, as determined by computed tomography scanning, at week 12 was comparable between BTX-A and BTX-B at a dose ratio of 1:70 (15.6 and 14.2%, respectively). At week 24, only masseters treated with BTX-A maintained a significant volume reduction. Investigator ratings and patient satisfaction scores paralleled objective computed tomography measurements. Conclusion: Both BTX-A and BTX-B are effective in the treatment of masseter hypertrophy. BTX-B, at a dose ratio of 1:70, has a comparable efficacy but a shorter duration of action than BTX-A.

Efficacy and safety of incobotulinum toxin A in periocular rhytides and masseteric hypertrophy: side-by-side comparison with onabotulinum toxin A

Background: Incobotulinum is a newly developed botulinum toxin A in which the complexing proteins had been removed. Objective: The aim was to compare the efficacy and safety of incobotulinum with onabotulinum in treating periocular rhytides and masseteric hypertrophy. Methods: A randomized, double-blind, split-face study was planned. Fifty-six patients were treated for periocular rhytides and the other 56 patients were treated for masseteric hypertrophy. Onabotulinum was injected on one side of the face and incobotulinum was injected on the other side of the face. The degree of periocular rhytides and masseteric hypertrophy was rated using Fitzpatrick Wrinkle Classification System (FWCS) and 10-point visual analogue scale (VAS) (0: the minimum to 10: the maximum). Objective and subjective rating was performed at pretreatment and every posttreatment follow-up visit by investigators and subjects. Result: The efficacy and safety of incobotulinum were not inferior to those of onabotulinum in treating periocular rhytides and masseteric hypertrophy up to 16 weeks after injection. There were no noteworthy differences in the onset time of effect between two botulinum toxins for periocular wrinkles and masseteric hypertrophy. No adverse event was reported. Conclusion: Incobotulinum provided non-inferior efficacy and safety for the treatment of periocular rhytides and masseteric hypertrophy compared with classic onabotulinum.

A comparison of the efficacy and safety of incobotulinum toxin A and onabotulinum toxin A in subjects with periocular rhytides and masseteric hypertrophy

A comparison of the efficacy and safety of incobotulinum toxin A and onabotulinum toxin A in subjects with periocular rhytides and masseteric hypertrophy

Surgical treatment of bilateral temporalis and masseteric hypertrophy: Report of a case

Hypertrophy of the masticatory muscles is characterized by generalized enlargement of the muscular tissue that affects the facial esthetic and may or not be accompanied by pain [1-3]. This condition can be congenital, but more often it is acquired. The origin has been attributed to muscle hyperactivity and parafunctionsoriginated from stressful lifestyle that causes bruxing or clenching [2,3]. Masseteric muscle hypertrophy is a relative common clinical entity that can affect one or both sides and is also thought to causesecondary enlargement of the mandibular angle as a result of functional remodeling. Temporalis muscle hypertrophy is a rare clinical entity and only a few cases are reported. More often, it presents a bilateral involvement and is usually associated with masseteric hypertrophy [3]. The aim of this report is to present a case of bilateral temporalis and masseteric muscles hypertrophy treated surgically

Role of Botox in Efficient Muscle Relaxation and Treatment Outcome: An Overview

Dear Editor, Smile is the most distinguished expression, and is the keystone of social interaction and communication. It is the universal welcoming greeting in all cultures and ethnicity. Just as a pleasant smile can act as a potential communication tool, an unpleasing smile can have the equally downbeat impact. Smile designing and functional restoration with dental implants, especially in partially edentulous patients, has become incredibly popular among prosthodontists in the last two decades. Botox is one of the most promising and exciting novel additions to the dentist’s arsenal for the treatment of temporomandibular disorder (TMD), mandibular spasm, prominent gums, masseteric hypertrophy and various cosmetic corrections. Botox is the generic name for the neurotoxin protein botulinum toxin Type A produced by fermentation of anaerobic bacterium Clostridium botulinum, which is a secure, sterilized and vacuum‑dried powder diluted with saline solution. In implant therapy, bone to implant union (osseointegration) can be impeded by excessive functional forces in patients with para‑functional habits. Additionally, implant overloading while healing can result in early implant failure primarily by cessation of the active osseointegration process. Botox therapy prior to implant surgeries has been shown to enhance prognosis and aesthetic advantages. This is especially true in patients with a known history of night clenching of teeth (bruxism), where prophylactic use of botox injections is very effective in achieving true bone to implant connection. Botox decreases the muscle activity by blocking overactive nerve impulses that trigger excessive muscular contractions by selectively preventing the release of the neurotransmitter acetylcholine (ACh) at the neuromuscular junction. [1] Pre‑surgical botox therapy also plays a key role in attaining muscular relaxation during surgical repair of multiple maxillofacial fractures associated with road traffic accident. Inappropriately attended hypertonic peri‑traumatic musculature may lead to impedance of formation of callus. [2] Excessive forces created by para‑functional clenching impede healing and reattachment of gums and bone in the mouth following trauma. Botox doses up to 61.7 U (range 25‑100 U) have been shown to achieve therapeutic response in bruxism, while higher doses (up to 150 U) are reported to significantly decrease pain and tenderness in temporalis and masseter muscles with improved function and mouth opening. [3‑5] Because the para‑functional activity usually leads to periodontal trauma in the form of trauma from occlusion, preventing such activity prior to and following periodontal surgery can promote the healing process. The use of a splint is often contraindicated because the teeth should be functional during healing. Nevertheless, curative approach via botox transiently inhibits normal oral function, which eventually comes back to previous levels once the effect of the drug has subsided. In spite of several controversies, botox therapy is a conventional, non‑invasive and pre‑surgical treatment that weakens the injected muscle but leaves the other muscles unaffected. The procedures are trouble‑free to complete by general dental practitioners, prosthodontists and cosmetic surgeons, with suitable instructions and guidelines. This letter is an attempt to draw attention toward the potential role of botox as an adjunct to prosthodontic surgery as well as in the context of maxillo‑facial trauma. I hope it will prove to be a gentle nudge to steer the researchers in this direction.

Role of Masseter Muscle β2-Adrenergic Signaling in Regulation of Muscle Activity, Myosin Heavy Chain Transition, and Hypertrophy

Chronic administration of clenbuterol (CB), a lipophilic β2-adrenoceptor (β2-AR) agonist, induces skeletal muscle hypertrophy and slow-to-fast fiber–type transitions in mammalian species, but the mechanism and pathophysiological roles of these changes have not been explored. Here, we examined the effects of CB not only on masseter muscle mass, fiber diameter, and myosin heavy chain (MHC) composition, but also on daily muscle activity, a factor influencing muscle phenotype, by means of electromyogram analysis in rats. MHC transition towards faster isoforms was induced by 2-week CB treatment. In addition, daily duty time was increased at 1 day, 1 week, and 2 weeks after the start of CB treatment and its increase was greater at high activity level (6-fold) than at low activity level (2-fold). In order to examine whether these effects of CB were mediated through muscle or CNS β2-AR stimulation, we compared these effects of CB with those of salbutamol (SB), a hydrophilic β2-AR agonist. SB treatment induced masseter hypertrophy and MHC transition, like CB, but did not increase daily activity. These results suggest that CB-mediated slow-to-fast MHC transition with hypertrophy was induced through direct muscle β2-AR stimulation, but the increase of daily duty time was mediated through the CNS. [Supplementary Figures: available only at http://dx.doi.org/10.1254/jphs.12271FP]

Botulinum toxin type A combined with cervical spine manual therapy for masseteric hypertrophy in a patient with Alzheimer-type dementia: a case report

ObjectiveThe purpose of this case study is to present the findings of combining botulinum toxin type A (BoNT-A) and cervical spine manual therapy to address masseter muscle spasticity in a patient with Alzheimer-type dementia. Case ReportA 78-year-old woman with bilateral spasticity of the masseteric regions for 2 years was referred for physiotherapy. She had trismus and bruxism, and could neither close nor open her mouth normally; thus, she was unable to be fed orally in a normal manner. Intervention and OutcomeThe patient underwent combined treatment with BoNT-A and cervical spine manual therapy. A medical physician (neurologist) performed the BoNT-A injections into 2 points at the center of the lower third of the masseter muscle. A physical therapist performed manual therapy interventions targeted at the cervical spine. Manual therapy started the day after the BoNT-A injection and continued for 5 sessions per week for a total period of 2 weeks. Clinical outcomes were measured including spasticity (Modified Ashworth Scale), functionality (Barthel Index), and jaw opening. Outcomes were conducted at baseline, 2 weeks after treatment, and at 2-month follow-up session after finishing the treatment. The patient improved in all of the outcomes at the end of treatment, and these results were maintained during the follow-up. After treatment, the patient was able to feed with minimal caregiver dependency because oral feeding was possible. ConclusionThe patient in this study responded positively to a combination of BoNT-A and manual therapy, resulting in decreased masseter muscles spasticity and improved trismus and bruxism.

Masseteric Hypertrophy: An Orthodontic Perspective

Masseteric hypertrophy, popularly called the benign masseteric hypertrophy (BMH) or idiopathic masseteric hypertrophy (IMH) is a relatively uncommon condition characterized by asymptomatic enlargement of one or both masseter muscles and is rarely accompanied by pain, which is often confused with parotid swelling. Most frequently, clinicians are consulted for swelling of angle of mandible which needs to be corrected for cosmetic reasons. Although it is tempting to produce malocclusions, bruxism, clenching, temporomandibular joint disorders, the etiology in majority of the cases are unknown. The purpose of this review is to have a discussion on the effects of masseter muscle on craniofacial morphology, its implication in different types of malocclusion and contemporary orthodontic management and stability.

The use of botulinum toxin type A in masseteric muscle hypertrophy: Long-term effects and lasting improvement

In this study, we aimed to evaluate the long-term efficacy of botulinum toxin A injection in reducing the masseter muscle thickness. Between 2007 and June 2008, we retrospectively analyzed the data from 28 patients (21 females, 7 males; mean age: 25.5±4.5 years; range 20 to 46 years) with benign masseter hypertrophy treated with botulinum toxin A injections. All patients were diagnosed by the morphometric analysis of the masseter muscle. The injections were repeated intermittently every six months and totally for six times. The patients were recalled and the last measurement was performed at a mean follow-up of 13.2 months. The values obtained following consecutive injections were compared and a statistically significant reduction in thickness of masseter muscle thickness after every single injection was found (p<0.001). The final measurement following treatment discontinuation revealed that this reduction was long-lasting. Botulinum toxin A injection is a safe and long-term effective therapy for the masseter muscle hypertrophy.

Management of Bilateral Masseter Muscle Hypertrophy

Masseter muscle hypertrophy is characterized by unilateral or bilateral enlargement of the masseter muscles affecting both females and males after puberty. Limitations on mouth opening, swollen cheek, and also tension in the region of the hypertrophied muscle are symptoms reported. Also, masseter hypertrophy can cause aesthetic and functional problems. A 40-year old woman was referred to our clinic with the chief complaint of facial appearance with square-face type. To eliminate undesirable facial appearance, surgical intraoral approach compromising reduction of deep masseter muscle with monocortical and bicortical ostectomy of the angle of the mandible was performed. The patient was satisfied with both functional outcomes and aesthetic outcomes on both facial profile and frontal view. No complication was seen intraoperatively and postoperatively after a 12-month follow-up period. This treatment modality would be suggested to gain optimal aesthetic results especially in a square face from the lateral profile.

Bruxism

Bruxism is an oral parafunctional activity, characterized by the teeth grinding and clenching of the jaw. It could cause a serious health problem. According to various studies, about 10% of human population has that kind of oral problem. The etiology of bruxism could be very diverse including some medical disorders, severe health conditions, some drugs, etc. Stress, anxiety and aggression could also trigger bruxism. Most frequent symptoms of bruxism are abrasion of the teeth, jaw pain, chewing disorders, migraines, neck pain, loss of teeth, gum recession, earache, temporomandibular joint pain, masseter hypertrophy as well as inflammation and blockade of some of salivary glands. One of the main symptoms in bruxism diagnosis is abrasion of the teeth; however, other symptoms, such as jaw pain, earache, neck pain and chewing disorders, should not be neglected. In severe, chronic cases, bruxism could lead to temporomandibular joint dysfunction such as pain, crepitation, chewing disorders and difficulties in opening the mouth. Bruxism can be very loud at night, so a sleeping partner or a parent may be the first to notice it and their observation is very important to indicate its presence. Today there are modern devices which can be used for monitoring the electromyography during sleep and identifying bruxism. If the diagnosis is made early and the real cause is identified, bruxism can be treated successfully. Reducing the stress is also very important in the treatment of bruxism. One of the most frequently used methods in the treatment of bruxism is the application of dental guards and splints. Splints are usually made of celluloid and silicone and they are designed to protect the teeth from abrasion, to reduce muscle forces, to stabilize the occlusion as well to prevent damage to the temporomandibular joints. In addition, bruxism can be treated by contingent electrical stimulation, biofeedback stimulation of the receptors for taste through taste buds, by switching the way of breathing from breathing through the nose to breathing through the mouth as well as by botulinum toxin (botox) and dietary supplements.

Management of unilateral masseter hypertrophy and hypertrophic scar-a case report.

Masseter muscle hypertrophy is a rare condition of idiopathic cause. It clinically presents as an enlargement of one or both masseter muscles. Most patients complain of facial asymmetry; however, symptoms such as trismus, protrusion, and bruxism may also occur. Several treatment options reported for masseter hypertrophy are present, which range from simple pharmacotherapy to more invasive surgical reduction. Keloid scar with unilateral masseter hypertrophy is a rarely seen in clinical practice. This paper reports a case of unilateral masseter hypertrophy with keloid scar in the angle of the mandible for which surgical treatment was rendered to the patient by using a single approach.

Surgical treatment of bilateral temporalis and masseteric hypertrophy: report of a case

Surgical treatment of bilateral temporalis and masseteric hypertrophy: report of a case

Abobotulinum toxin A and onabotulinum toxin A for masseteric hypertrophy: a split-face study in 25 Korean patients

Masseter muscle hypertrophy has been treated for cosmetic purposes using several modalities, including injection of type A or type B botulinum toxin into the masseter muscle. In this report, we compared the efficacy and safety of abobotulinum toxin A with onabotulinum toxin A treatment for masseteric hypertrophy in 25 Korean patients with a conversion factor of 2.5:1 through a controlled, split-face, and evaluator-blinded study. The mean grade of clinical improvement based on clinical assessment was 2.8 ± 0.9 for abobotulinum toxin A and 2.7 ± 0.8 for onabotulinum toxin A at 8 weeks after the injection. At 12 weeks after the injection, the mean grade of clinical improvement based on clinical assessment was 2.9 ± 0.9 for abobotulinum toxin A and 2.7 ± 0.8 for onabotulinum toxin A. More pronounced improvement was observed with abobotulinum toxin A than onabotulinum toxin A in three (12%) patients at 8 weeks and five (20%) patients at 12 weeks. We believe that our data can be used as an essential reference for determining the dose of type A botulinum toxin in the treatment of masseteric hypertrophy.