Treatment of unilateral masseteric hypertrophy with botulinum toxin: case report

Botulinum Toxin Injection for Masseteric Hypertrophy Using 6 Point Injection Technique - A Case Report. Proposal of a Clinical Technique to Quantify Prognosis

Introduction

Masseter hypertrophy presents as unilateral or bilateral swellings over the ramus and angle of the mandible. It is caused by malocclusion, clenching, TMJ disorders, etc and alters facial symmetry, leading to discomfort and negative cosmetic impact in many patients, making this a popular request for aesthetic and functional correction.

Materials and Methods

This case report involves injecting Botulinum toxin into 6 equidistant bulging points on the masseter. Standardized photography and clinical parameters were used to assess facial contour and masseter muscle thickness at baseline and successive follow ups.

Results and Discussion

Significant masseteric bulk reduction was observed in subsequent follow ups.

Conclusion

The 6-point technique was found to be an effective treatment modality for Botox injection in masseteric hypertrophy. The clinical method to quantify prognosis was easy and economical.

Efficacy of botulinum toxin in masseter muscle hypertrophy for lower face contouring

BACKGROUND

Masseter muscle hypertrophy (MMH) usually presents with cosmetic concerns as it may lead to widening of the lower face. Apart from the traditional surgical approaches, botulinum toxin type A (BTA) injection is a non-invasive treatment option available. There are no standard guidelines for this procedure.

OBJECTIVES

To study the efficacy of botulinumtoxin A in MMH for lower face contouring.

METHODOLOGY

The Cochrane Library, PubMed/MEDLINE, Google-scholar, Science-Direct database, and ResearchGate from inception until September 2021 were searched using the keywords "botulinumtoxin type A," "masseter muscle hypertrophy," "lower face contouring," and "masseter botox." All available retrospective and prospective studies, case-series, case-reports, and expert reviews were included with an emphasis on efficacy of BTA in MMH and units injected into the muscle, points of placement, adverse events, and the duration of its effect. Reference lists of the resultant articles, as well as relevant reviews, were also searched.

RESULT

40 articles were shortlisted for the review, of which 14 studies with sample-size ≥10 in accordance with the study requirements were summarized in a tabular form for analysis and easy comparison and reference.

CONCLUSION

BTA injection is a non-invasive, safe, and effective treatment for MMH. The optimum number of BTA units could not be ascertained due to wide variability in the studies as well as ethnicity of patients and extent or some measurement of MMH. The points of placement of injection should be well within the boundaries of the masseter muscle. The maximum effect of BTA after a single injection session is usually seen in ~3 months, and the duration may last for 6-12 months. Multiple injection sessions may be required to maintain a long-term effect. Injection technique and total number of injection units of neuromodulator must be individualized for each patient.

Histological features of masticatory muscles after botulinum toxin A injection into the right masseter muscle of dystrophin deficient (mdx-) mice

OBJECTIVE/BACKGROUND

The most frequently used animal model for human DMD (Duchenne muscular dystrophy) research is the mdx mouse. In both species, characteristic histological changes like inflammation, muscle fiber degeneration and fibrosis are the same, but in contrast to humans, in mdx mice, phases of muscle fiber degeneration are compensated by regeneration processes.

AIM

Therefore, the interest of this study was to evaluate histological features in masticatory muscles after BTX-A injection into the right masseter muscle of wild type and dystrophic (mdx) mice, illustrating de- and regeneration processes induced by this substance.

MATERIAL AND METHODS

The right masseter muscle of 100 days old healthy and mdx mice were selectively paralyzed by a single intramuscular BTX-A injection. Masseter as well as temporal muscle of injection and non-injection side were carefully dissected 21 days and 42 days after injection, respectively, and fiber diameter, cell nuclei position, necrosis and collagen content were analyzed histomorphologically in order to evaluate de- and regeneration processes in these muscles. Statistical analysis was performed using SigmaStat Software and Mann Whitney U-test (significance level: p < 0.05).

RESULTS

At both investigation periods and in both mouse strains fiber diameter was significantly reduced and collagen content was significantly increased in the right injected masseter muscle whereas fiber diameters in mdx mice were much smaller, and these differences were even more apparent at the second investigation period. Necrosis and central located nuclei could generally be found in all mdx mice muscles investigated with an amount of centronucleation exceeding 60%, and a significant increase of necrosis six weeks after injection. In wild type mice central located nuclei could primarily be found in the treated masseter muscle with a portion of 2.7%, and this portion decreased after six weeks, whereas in mdx mice a decrease could also be seen in the non-injected muscles. In contrast, in wild type mice necrosis was not apparent at any time and in all muscles investigated.

CONCLUSION

From our results it can be concluded that in mdx mice masticatory muscles de- and regeneration processes were extended, triggered by a selective BTX-A injection, or mdx mice at this age, independently of BTX-A treatment, went through another cycle of de- and regeneration as a characteristic of this disease.

Aesthetic Applications of Botulinum Toxin A in Asians: An International, Multidisciplinary, Pan-Asian Consensus

Background:

Botulinum toxin type A remains the most popular nonsurgical aesthetic treatment worldwide. Previous consensus statements have focused on Caucasians and on Koreans as generally representative of Asians. However, indications and dosages vary among different ethnic groups. This publication reports the results of a multidisciplinary, pan-Asian consensus focusing on incobotulinumtoxinA.

Methods:

A consensus group of plastic surgeons and dermatologists from Asia, Europe, and the United States convened for a live meeting in Asia, followed by a questionnaire-based Delphi procedure. Treatment of Asians in both their native countries and countries of migration was discussed.

Results:

For most items, the group achieved a majority consensus. A number of treatment indications, strategies, and dosages were identified in Asians, which are distinct to those previously described for Caucasians due to differences in facial morphotypes, anatomy, and cultural expectations. The group also formulated position statements for intradermal botulinum toxin type A (“mesotoxin”), body shaping with the calves as a paradigm, and reduction of parotid glands. While Asians have previously been considered a homogeneous group for the purposes of aesthetic treatment, this publication considers regional variations. A new classification of Asian facial morphotypes is proposed to aid treatment planning and implementation.

Conclusions:

This is the first pan-Asian consensus for aesthetic use of botulinum toxin type A. Its unique objective is to optimize treatment safety and efficacy for patients of complete or part-Asian ancestry in all regions. The recommendations for incobotulinumtoxinA may be extended with care to other botulinum toxin formulations.

Three-dimensional CT might be a potential evaluation modality in correction of asymmetrical masseter muscle hypertrophy by botulinum toxin injection

For correction of this asymmetrical hypertrophy, botulinum toxin type A (BTxA) injection is one of convenient treatment modalities. Unfortunately, physical examination of masseter muscle is not enough to estimate the exact volume of muscle hypertrophy difference. Two Koreans, male and female, of bilateral masseter hypertrophy with asymmetricity were evaluated. BTxA (NABOTA(®), Daewoong, Co. Ltd., Seoul, Korea) was injected at master muscle site with total 50 U (25 U at each side) and volume change was evaluated with three-dimensional (3D) CT image analysis. Maximum reduction of masseter hypertrophy was recognized at 2-month follow-up and reduced muscle size started to restore after 3 months. Mean reduction of masseter muscle volume was 36% compared with baseline. More hypertrophied side of masseter muscle presented 42% of volume reduction at 2-month follow-up but less hypertrophied side of masseter muscle showed 30% of volume shrinkage. In conclusion, 3D CT image analysis might be the exact evaluation tool for correction of asymmetrical masseter hypertrophy by botulinum toxin injection.

Prolonging the duration of masseter muscle reduction by adjusting the masticatory movements after the treatment of masseter muscle hypertrophy with botulinum toxin type a injection

BACKGROUND

Botulinum toxin type A (BTX-A) is widely used for the clinical treatment of masseteric hypertrophy. Until now, few reports have discussed how to prolong the duration of its effectiveness.

OBJECTIVE

This study evaluated that purposely adjusting the masticatory movements is possible of postponing the masseter muscle rehypertrophy.

METHODS

Ninety-eight patients were randomly and equally divided into 2 groups, and 35 U BTX-A per side was injected into the masseters. The thickness and volume of the masticatory muscles were measured by ultrasound and computerized tomography, respectively. Patients in Group 1 were instructed to strengthen their masticatory effort during the denervated atrophic stage of the masseter (the interval was evaluated by real-time ultrasound monitoring), whereas patients in Group 2 were not given this instruction. When the masseter muscle began to recover, patients in both groups were instructed to reduce their chewing.

RESULTS

The duration of the masseter muscle rehypertrophy was significantly prolonged in Group 1 patients. The thickness and the volume of the other masticatory muscles were significantly increased in Group 1 but were either slightly decreased or insignificantly different in Group 2.

CONCLUSION

Purposely strengthening masticatory muscle movement during the denervated atrophic stage of the masseter can prolong the duration of masseter rehypertrophy.

BOTOX: 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.

Salivary gland disorders

Patients with salivary gland disease present with certain objective and/or subjective signs. An accurate diagnosis for these patients requires a range of techniques that includes the organized integration of information derived from their history, clinical examination, imaging, serology, and histopathology. This article highlights the signs and symptoms of the salivary gland disorders seen in the Salivary Gland Center, and emphasizes the methodology used to achieve a definitive diagnosis and therapy.

Botulinum toxin: The Midas touch

Botulinum Toxin (BT) is a natural molecule produced during growth and autolysis of bacterium called Clostridium botulinum. Use of BT for cosmetic purposes has gained popularity over past two decades, and recently, other therapeutic uses of BT has been extensively studied. BT is considered as a minimally invasive agent that can be used in the treatment of various orofacial disorders and improving the quality of life in such patients. The objective of this article is to review the nature, mechanism of action of BT, and its application in various head and neck diseases.

Isolated unilateral temporalis muscle hypertrophy

Isolated unilateral temporalis muscle hypertrophy is an extremely rare cause of swelling in the temple region, with only 7 cases reported in the literature. The authors report the eighth case of this unique occurrence in a 17-year-old boy and review the current literature.

Salivary gland disorders

Salivary gland abnormalities and salivary dysfunction are important orofacial disorders. Patients with such problems are usually seen in the dental office for evaluation and therapy, and the dental practitioner is required to make a diagnosis and institute care. Therefore, it is necessary for the dentist to be knowledgeable regarding the more common pathologic entities that involve the salivary apparatus, and also be familiar with the diagnostic and therapeutic tools that are available. Successful diagnosis is dependent on the organized integration of the information derived from past history, clinical examination, salivary volume study, imaging, serology, and histopathologic examination. This article discusses the most common disorders seen in the Salivary Gland Center and indicates the current approaches to diagnosis. Improvement in diagnostic skills will avoid serious complications and lead to specific and effective therapy.

Intramuscular nerve distribution of the masseter muscle as a basis for botulinum toxin injection

The aim of this study was to determine intramuscular distribution pattern of the masseteric nerve, thus providing information regarding the most efficient and safe site for botulinum toxin (BTX) injection for conventional BTX intervention therapy in the treatment of masseteric hypertrophy.Twelve masseter muscles were dissected, and the pattern of innervation of the masseteric nerve was observed in the superficial, middle, and deep layers. We also analyzed 10 muscles that had been stained using Sihler's staining technique.The nerve branches from the posterosuperior and posteroinferior groups innervating the deep and middle layers of the masseter muscle, respectively. Among the nerve twigs originating from the anteroinferior nerve group, 2 or 3 perforated the superficial layer of the muscle. Observation of stained specimens revealed that all perforating branches innervating the superficial layer were mainly confined to and distributed within areas V or VI.Between 2 and 4 perforating branches supply the superficial layer of the masseter muscle. In addition, the richest arborization of the perforating masseteric nerve branches is confined mostly to area V, approximately in accordance with the BTX injection point that is currently used clinically. Area V is thus strongly recommended as the most efficient and safe BTX injection area for the treatment of masseteric hypertrophy.

Peculiar presentation of bilateral temporalis muscle hypertrophy--report of a case and review of literature

PURPOSE

Temporal hypertrophy is a rare clinical entity, especially the bilateral variety, whereas masseteric hypertrophy is a commonly occurring disorder. Very few bilateral cases are reported in literature. We are reporting a case with bilateral temporalis muscle hypertrophy with peculiar symptoms which is not reported so far in literature.

Effect of botulinum toxin injection on nocturnal bruxism: a randomized controlled trial

OBJECTIVE

To evaluate the effect of botulinum toxin type A on nocturnal bruxism.

DESIGN

Twelve subjects reporting nocturnal bruxism were recruited for a double-blind, randomized clinical trial. Six bruxers were injected with botulinum toxin in both masseters, and six with saline. Nocturnal electromyographic activity was recorded in the subject's natural sleeping environment from masseter and temporalis muscles before injection, and 4, 8, and 12 wks after injection and then used to calculate bruxism events. Bruxism symptoms were investigated using questionnaires.

RESULTS

Bruxism events in the masseter muscle decreased significantly in the botulinum toxin injection group (P = 0.027). In the temporalis muscle, bruxism events did not differ between groups or among times. Subjective bruxism symptoms decreased in both groups after injection (P < 0.001).

CONCLUSIONS

Our results suggest that botulinum toxin injection reduced the number of bruxism events, most likely mediated its effect through a decrease in muscle activity rather than the central nervous system. We controlled for placebo effects by randomizing the interventions between groups, obtaining subjective and objective outcome measures, using the temporalis muscle as a control, and collecting data at three postinjection times. Our controlled study supports the use of botulinum toxin injection as an effective treatment for nocturnal bruxism.

Growth effects of botulinum toxin type A injected into masseter muscle on a developing rat mandible

OBJECTIVES

Botulinum toxin type A (BTX-A) reduces the muscular contractions by temporarily inhibiting the release of acetylcholine at the neuromuscular junction. The purpose of this study was to investigate the effects of the BTX-A injected into the masseter muscle of a developing rat mandible.

MATERIALS AND METHODS

Four-week-old male (no. 80) Sprague-Dawley rats were divided into four groups: control group, saline group, BTX-A group and baseline control group. Rats of baseline group were sacrificed at 0 day to provide baseline values of the mandibular measurements. The masseter muscle of rats in the saline and the BTX-A group were administered with saline and BTX-A solutions respectively. Experimental animals were sacrificed after 4 weeks.

RESULTS

The BTX-A group demonstrated smaller mandibular dimension compared with the other groups (P < 0.05). Their condylar cartilages showed increased apoptosis at the proliferation stage of the reserve zone and masseter muscle fibers demonstrated atrophic changes.

CONCLUSIONS

The result demonstrated BTX-A influence on inhibitory action of the developing mandible because of apoptosis at the proliferation stage of the reserve zone of the condylar cartilage in developing rat mandible.

Unilateral temporalis muscle hypertrophy with contralateral masseteric hypertrophy

We report the MRI findings of a 22-year-old woman who complained of localized swelling in the left temporal region and right side of the face. MRI revealed left temporal and right masseter muscle hypertrophy, which to our knowledge has not been reported previously. The diagnosis of benign masticatory muscle hypertrophy was confirmed by biopsy.

Bilateral temporalis muscle hypertrophy: a case report

Although masseteric hypertrophy is common and can be accompanied by temporalis hypertrophy, temporalis hypertrophy by itself is an exceptional finding. A patient, a chronic bruxer who was receiving psychiatric care and psychotherapeutic medications, complained of moderate discomfort and swelling in both temporal areas. It is believed that the patient's long-term stress-related sleeping problem was causing her bruxism. Of great interest was the fact that chronic bruxing had resulted in the rare occurrence of temporalis muscle hypertrophy without a coexisting masseteric hypertrophy.

Die Chemodenervation mit Botulinumtoxin bei Masseterhypertrophie

BACKGROUND

Masseteric hypertrophy is a unilateral or bilateral enlargement of the masseteric muscle of various aetiologies. The therapeutic options range from solely conservative measures, especially in functionally induced abnormalities, up to surgical ablation of the muscle. The presented study evaluates the application of botulinum toxin serotype A for the treatment of masseteric hypertrophy.

PATIENTS AND METHODS

Between June 2000 and August 2004 seven patients with a unilateral and one patient with a bilateral manifestation of the condition were treated by an injection of botulinum toxin.

RESULTS

A significant improvement of facial asymmetry caused by chemodenervation and following reduction of the hypertrophic muscle mass could be achieved in all cases. Complications during the injection, side effects, signs of intoxication, and therapy failure were not observed.

CONCLUSION

The results of this treatment series show in agreement with the reports in the literature that the application of botulinum toxin can be currently considered as the therapy of choice in masseteric hypertrophy.

Botulinum toxin type A in the management of masseter muscle hypertrophy

PURPOSE

We sought to evaluate the response of 6 patients with masseter muscle hypertrophy to botulinum toxin type A therapy.

PATIENTS AND METHODS

Six patients with unilateral or bilateral masseter muscle hypertrophy received intramuscular injection of the botulinum toxin type A. The functional and cosmetic results were evaluated as well as recurrence.

RESULTS

In all patients, satisfactory regression of the masseter muscle hypertrophy occurred and mild muscular pain was relieved. Recurrence was observed in 2 cases.

CONCLUSIONS

The use of botulinum toxin type A in masseter muscle hypertrophy therapy was shown to be a successful and safe treatment method. This procedure to control parafunctional activities involving the masticatory muscles of patients appears to be useful.

Selective Neurectomy of the Masseteric Nerve in Masseter Hypertrophy

Asian women prefer to have more delicate and feminine features rather than prominent squared mandibular angles. It was proposed that a selective neurectomy of the masseteric nerve might result in muscular atrophy and subsequent reduction of the hypertrophic mass of the masseter muscle. This study is aimed at an elucidation of the precise course of the masseteric nerve and the impact of a neurectomy in case of masseter hypertrophy. Eleven heads of Korean cadavers were halved and dissected. The masseteric nerve and artery in the mandibular notch were clearly located. A selective neurectomy of the masseteric nerve was performed in four cases of masseter hypertrophy. The masseteric nerve and artery behind the temporalis muscle at the mandibular notch cross over to the masseter. The masseteric nerve was found 11.3 +/- 2.6 mm horizontally from the anterior border of the ramus and 11.3 +/- 2.6 mm above the mandibular notch and the superior masseteric artery, 25.6 +/- 3.7 mm from the ramus, and 7.8 +/- 2.6 mm above the notch. A neurectomy of the masseteric nerve can be used to reduce the hypertrophied masseter and as an ancillary procedure of mandibular angle ostectomy. One procedure can accompany another in the reduction of a prominent mandibular angle.

The management of oromandibular motor disorders and facial spasms with injections of botulinum toxin

Although much work is yet to be done in this area, nine general conclusions can be derived: 1. Local site-of-injection side effects from botulinum toxin injections are rare, assuming proper technique is used. 2. The two most common medication-related side effects from botulinum toxin orofacial injections are alterations in salivary consistency and inadvertent weakness of the swallowing, speech, and facial muscles. These complications are injection site-specific (eg, more common with lateral pterygoid injections and palatal and tongue muscle injections) and dose-dependent problems. These problems are bothersome but are not contraindications for the therapy if it is needed. 3. The data presented in this article are mostly case series-based and open trial-based information that is promising, but randomized, blinded, controlled trials are needed to establish the true efficacy of this method for the orofacial motor and pain disorders. 4. The novice should begin with injection of muscles he or she can inject with low risk of incorrect placement. The hard-to-find muscles should be avoided when starting out. The novice clinician should inject and dissect a few cadavers to improve injection technique. 5. The general latency for botulinum toxin type A is 1 week, its duration is 2 to 3 months, and it is recommended that injection be done no more than once every 12 weeks to avoid development of antibodies against the toxin. 6. Depending on the target muscle, injection dose is 10 to 50 U of Botox type A per site with a total dose of 200 U in the masticatory system. More than this can be used (400 U maximum) if other sites in the head and neck are included in the injection protocol. 7. Regarding injecting painful muscles that do not exhibit palpable muscle hardness or EMG-determined spasticity or observable involuntary movements but have chronic myofascial trigger points or the patient localizes them as the site of their chronic daily headache pain, botulinum toxin injections might be helpful used in this manner, but conclusive data for this controversial application of botulinum toxin are still missing. 8. Hemifacial spasm has the largest number of open-label, clinical trials, some of which have a 10-year follow-up. The conclusions reached by all of these reports is that treatment of hemifacial spasm with repeated injections of botulinum toxin has been highly successful and that the dose and relative effect of the injections are stable over time. 9. Although EMG-guided injection may be useful, EMG is neither practical nor needed in most situations for orofacial injections because most of the orofacial muscles are easily palpable muscles or have definitive bony landmarks to help with the localization process.

Effects of botulinum toxin type A on bilateral masseteric hypertrophy evaluated with computed tomographic measurement

BACKGROUND

A paucity of reports exist on the use of botulinum toxin type A injections as an alternative noninvasive treatment for masseteric hypertrophy.

OBJECTIVE

To evaluate the effects of botulinum toxin type A on masseteric hypertrophy using computed tomography.

METHODS

Percutaneous intramuscular injections of botulinum toxin type A of 30 U per side was carried out in 11 subjects with masseteric hypertrophy. The changes in the masseteric muscle volume before and 12 weeks after injection were evaluated using computed tomography. The changes in the lower facial contours on the photographs were evaluated as excellent, good, fair, and no changes.

RESULTS

Nine of the 11 subjects showed a mean reduction of approximately 22% in the masseteric muscle volume. The maximum reduction was 35.4% (range, 8.1% to 35.4%). Nine subjects showed aesthetically good results with a grade of good or excellent at 12 weeks after treatment.

CONCLUSION

Botulinum toxin injections are a noninvasive alternative method for treating masseteric hypertrophy.

Botulinum toxin type A treatment for contouring of the lower face

BACKGROUND

Since type A botulinum toxin was first reported for the treatment of masseter muscle hypertrophy in 1994, there have been few reports about cosmetic indications for contouring procedures of the lower face with injection of botulinum toxin type A, and this procedure remains unpredictable.

OBJECTIVES

This study attempted a quantitative prospective analysis of reduction of masseter muscle hypertrophy after Botox injection, using ultrasound and computerized tomography (CT) scans to analyze the possible use of botulinum toxin type A as a contouring procedure for the lower face.

METHODS

Forty-five patients consented to the study and received a contouring procedure of the lower face from November 2001 to April 2002. Twenty five to 30 U of Botox per side was injected at five to six points into the prominent portions of the mandibular angle. Serial measurements were made of the thickness of the masseter muscle by ultrasound and CT before the injections and at 1 and 3 months thereafter. A quantitative analysis for the masseter thickness changes was performed on just one patient who underwent all ultrasound and CT scans. Statistical analysis of the masseter thickness change was by two-way and multiple comparison analysis. To evaluate clinical long-term effects, the patient's satisfaction with the procedure and any side effects after injections were monitored during 4 to 10 months of follow-up.

RESULTS

Among the total of 45 patients, 15 underwent the three ultrasound measurements, and 14 had the three CT measurements. With regard to quantitative analysis of the thickness change to the masseter on both sides of the face according to time points, this was gradually reduced by both the ultrasound and CT measurements during the first 3 months. By ultrasound, the maximum reduction in masseter thickness was seen 1 month after the injections, with a slight increase being observed at 3 months after injection. A continued reduction of masseteric muscle thickness was seen on the CT up to 3 months after injection. In terms of patient satisfaction for up to 10 months of follow-up, the results were as follows: very satisfied, 1; satisfied, 36; slight improvement, 3; no change or dissatisfied, 5. Main local side effects included masticatory difficulties, muscle aching at injection sites, and speech disturbance. However, these side effects were transitory, usually lasting from 1 to 4 weeks after the injections.

CONCLUSIONS

Preliminary results from this study suggest that an injection of Botox resulted in relatively satisfactory clinical effects, although there was only a short-term follow-up. It is suggested that the use of botulinum toxin type A for contouring of the lower face can be established as a simple, predictable, alternative facial contouring procedure without a prolonged recovery time.

Masseteric hypertrophy associated with administration of anabolic steroids and unilateral mastication: a case report

In this report we present a patient with unilateral masseteric hypertrophy who used anabolic steroids and was chewing entirely unilaterally for 1 month. Computed tomography and histologic examination were used to confirm the diagnosis. The combined action of unilateral mastication and anabolic steroid use is probably responsible for the rapid development of unilateral masseteric hypertrophy.