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Gazi Sağlık Bilimleri Dergisi 2023:8 (1): 108-113 Derleme
İletişim/Correspondence E-posta: orhankazan@gazi.edu.tr
Orhan Kazan Geliş tarihi/Received: 26.01.2023
Health Services Vocational School, Gazi University Kabul tarihi/Accepted: 31.01.2023
Ankara, Turkey DOI: 10.52881/gsbdergi.1243014
PAROXYSMAL BUILDING PHENOMENA AFTER MASSETER BOTOX INJECTIONS;
CASE SERIES AND REVIEW OF THE LITERATURE
1
Orhan KAZAN1, Mehmet Emin TOPRAK2
1Assistant Professor, Health Services Vocational School, Gazi University, Ankara, Turkey.
https://orcid.org/0000-0001-8762-0533
2Assistant Professor, Gazi University Faculty of Dentistry, Department of Oral and Maxillofacial Surgery, Ankara, Turkey.
https://orcid.org/0000-0003-4281-5913
ABSTRACT
Aim: The temporomandibular joint (TMJ), also known as the mandibular joint; is a nearby the synovial joint that
connects the mandible to the temporal bone the external auditory canal. Although TMJ disorders are frequently seen;
they can be caused by many reasons such as disorders caused by masticatory muscles, condyle and articular disc
incompatibility, inflammatory joint diseases, chronic mandibular hypomobility, and congenital or acquired muscle and
bone disorders.
Case reports: In our study, the diagnosis and treatment process of 4 patients who applied to the Gazi University Faculty
of Dentistry Department of Oral and Maxillofacial Surgery clinic with complaints of TMJ pain were presented. All of
the cases had masseter hypertrophy due to bruxism. Botulinum toxin-A (BTA) was injected to the masseter muscles
bilaterally after written informed consents were obtained from each patients before the procedure. In the control
examinations an unexpected paradoxical masseteric bulging was detected. A more superficial BTA injection was applied
to the superficial lobe of the masseter muscles that was not affected by BTA in presented patients and the complaints
were dissolved in ten days.
Conclusions: The cases presented in our article have a rare complication of BTA injections and can be treated easily
after a correct diagnosis by the physician. Physicians who perform BTA injections for bruxism and masseter hypertrophy
should be aware of the possible complications and should have sufficient knowledge and experience to overcome it.
Keywords: Temporomandibular joint, botox, masseteric swelling, paradoxical masseteric bulging, bruxism.
MASSETER BOTOKS ENJEKSİYONU SONRASI GELİŞEN PARADOKSAL BULGİNG
FENOMENİ; VAKA SERİLERİ VE LİTERATÜR DERLEMESİ
ÖZ
Amaç: Mandibular eklem olarak da bilinen temporomandibular eklem (TME); dış kulak yolunun önünde mandibulayı
temporal kemiğe bağlayan sinoviyal bir eklemdir. TME rahatsızlıkları toplumda sıklıkla görülmekle beraber; çiğneme
kaslarından kaynaklanan bozukluklar, TME’de kondil ve disk uyumsuzlukları, inflamatuar eklem hastalıkları, kronik
mandibular hipomobilite, konjenital ya da kazanılmış kas ve kemik rahatsızlıkları gibi birçok nedenden
kaynaklanabilmektedir.
Vaka raporları: Çalışmamızda eklem ağrısı şikayetleri ile Gazi Üniversitesi Diş hekimliği Fakültesi Ağız, Diş ve Çene
Cerrahisi Kliniğine başvuran 4 hastanın teşhis ve tedavi süreci sunulmuştur. Olguların hepsinin bruksizme bağlı masseter
hipertrofisinin olduğu tespit edildi. İşlem öncesi hastalardan yazılı olarak alınan aydınlatılmış onam sonrasında,
botulinum toksin-A (BTA) uygulaması yapıldı. Uygulamanın sonrası yapılan kontrol muayenelerinde 4 olguda da
paradoksal masseterik şişlik tespit edildi. Çalışmamızda sunulan hastaların botokstan etkilenmeyen masseter kaslarının
yüzeyel loblarına daha yüzeyel bir botoks enjeksiyonu yapıldı, ortalama on gün içerisinde bütün hastalarda şikayetlerin
ortadan kaktığı görüldü.
Sonuç: Masseter botoksu sonrası paradoksal şişlik fenomeni nadir görülmekte olup, hekim tarafından doğru konulan
teşhis sonrasında kolaylıkla tedavi edilebilmektedir. Bruksizm ve masseter hipertrofisi için botoks uygulamalarını yapan
hekimlerinin ortaya çıkabilecek olası komplikasyonlarla ilgili bilgili sahibi olması ve gerekli çözümleri sunabilmesi
gerekmektedir.
Anahtar sözcükler: Temporomandibular eklem, botoks, masseterik şişlik, paradoksal masseterik şişlik, bruksizm.
1
This study was presented in the 29th International Scientific Congress of Turkish Association of Oral and
Maxillofacial Surgery, Antalya, Turkiye.
Gazi Sağlık Bilimleri Dergisi 2023: 8 (1): 108-113 Kazan ve Toprak
109
INTRODUCTION
The temporomandibular joint (TMJ),
known as the mandibular joint, is a type of
synovial joint with bicondylar articulation
(1). The term temporomandibular disorder
(TMD) is used for disorders in the joint,
muscle and bone structure in the TMJ
region. Among the most common TMJ
disorders; pain dysfunction syndrome,
internal diseases of the joint, arthritis and
traumas (2-4).
Masseter muscle hypertrophy; is defined as
a rare clinical phenomenon characterized by
a local swelling in the area close to the
angulus of the mandible, the exact etiology
of which is unclear, but often caused by
causes such as bruxism, TMD, and
malocclusion. Treatment options such as
non-invasive pharmacological treatment
and invasive surgical reduction are
available for patients diagnosed with
masseter hypertrophy. Botulinum toxin
type A (BTA) injection, a less invasive
technique, is a toxin produced by the
anaerobic organism Clostridium botulinum.
It causes temporary paraesthesia and
muscle atrophy after injection (5, 6).
BTA has been used frequently in the
treatment of masseter hypertrophy in recent
years and is considered to be safe compared
to surgical treatment (7, 8). In the
anatomical and clinical studies carried out
since the beginning of its use in treatment;
Various complications such as swelling,
bruising, muscle weakness, and undesirable
changes in facial muscles have been
reported (9, 10).
It has been reported that the cause of
paradoxical masseteric swelling, which is
among the low complications that may
occur after BTA injection, is due to the
thickness of the deep inferior tendon located
between the two superficial and deep lobes
of the masseter muscle as a result of
anatomical studies (11).
CASE REPORTS
Case-1
A 34-year-old female patient with no
systemic disease applied to the Gazi
University Faculty of Dentistry Department
of Oral and Maxillofacial Surgery clinic
with a complaint of pain in TMJ. The
clinical examination, it was determined that
she had bruxism and hypertrophy in the
bilateral masseter muscles. It was also
observed that the patient had abrasions on
the occlusal surfaces of her teeth. Written
informed consent was obtained from the
patient before clinical examination and
interventional procedure. The BTA was
injected into the masseter muscles
bilaterally (25 Units). Bilateral paradoxical
masseteric swelling was detected in the
control examinations performed one week
later (Figure 1). A more superficial BTA
injection was made into the superficial
muscle lobes of the masseter muscles that
were not affected by botox (10 Units). The
patients were informed and followed up.
After 10 days, it was determined that the
bulging was completely solved.
Figure 1: Bilateral paradoxical masseteric
bulging detected on extraoral examination
in first patient.
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110
Case-2
A 28-year-old female patient with no
systemic disease, was referred to the Gazi
University Oral and Maxillofacial Surgery
clinic with complaints of discomfort in TMJ
and limitation of mouth opening, especially
in the morning. On clinical examination,
she was found to be a bruxism patient. In the
clinical examination, it was determined that
she had bruxism and hypertrophy in the
bilateral masseter muscles. Written
informed consent was obtained from the
patient before clinical examination and
interventional procedure. The BTA was
injected into the masseter muscles
bilaterally (25 Units). Bilateral paradoxical
masseteric bulging was detected in the
control examinations performed one week
later (Figure 2).
Figure 2: Bilateral paradoxical masseteric
bulging during muscle contraction in the
second case
A more superficial BTA injection was made
into the superficial muscle lobes of the
masseter muscles that were not affected by
botox (10 Units). The patients were
informed and followed up. After 7 days, it
was determined that the bulging was
completely solved.
Case-3
A 30-year-old healthy female patient
applied to the Gazi University Oral and
Maxillofacial Surgery clinic with a
complaint of clenching. The patient was
found to be a bruxist. In the clinical
examination, it was determined that she had
bruxism and hypertrophy in the bilateral
masseter muscles. Written informed
consent was obtained from the patient
before clinical examination and
interventional procedure. The BTA was
injected into the masseter muscles
bilaterally (25 Units). Bilateral paradoxical
masseteric bulging was detected in the
control examinations performed one week
later (Figure 3). A more superficial BTA
injection was made into the superficial
muscle lobes of the masseter muscles that
were not affected by botox (10 Units). The
patients were informed and followed up.
After 10 days, it was determined that the
bulging was completely solved.
Figure 3: In the third case, bilateral
paradoxical masseteric bulging ten days
after injections
Case-4
A 25-year-old female patient who have no
general health problem, applied to the Gazi
University Oral and Maxillofacial Surgery
clinic with a complaint of clenching. On
clinical examination, the patient was found
Gazi Sağlık Bilimleri Dergisi 2023: 8 (1): 108-113 Kazan ve Toprak
111
to have masseter hypertrophy bilaterally.
Written informed consent was obtained
from the patient. The BTA was injected into
the masseter muscles bilaterally (20 Units).
Bilateral paradoxical masseteric bulging
was detected in the control examinations
performed one week later (Figure 4). A
more superficial BTA injection was made
into the superficial muscle lobes of the
masseter muscles that were not affected by
botox (15 Units). The patients were
informed and followed up. After 12 days, it
was determined that the bulging was
completely solved.
Figure 4: Bilateral paradoxical masseteric
bulging of superficial muscle lobes of
fourth patient
DISCUSSION
BTA injection, which is widely used in the
treatment of masseter muscle hypertrophy,
is a popular technique due to its optimal
therapeutic effect (12). Paradoxical
masseteric swelling is defined as an
unexpected swelling of the masseter muscle
as a result of BTA injections. According to
recent studies, it is rarely seen and its
incidence is between 0.5% and 18.8% (13).
It usually occurs within 2-4 weeks after
injection, but it has been reported that it can
start within 24 hours (14). According to
recent studies, it is rarely seen and its
incidence is between 0.5% and 18.8%. It is
thought to be induced by contractions of
unaffected muscle bundles distant from the
BTA injection area (11).
The technique has been described in a large
body of literature on BTA injection sites.
Among them; There are injections applied
to the most protruding part that is palpated
when the masseter muscle is contracted
from a single point, injections made from
two points, and injections made from 3-4
points (15-17). In the cases we present, for
the area planned to be injected into the
masseter muscle; The imaginary line
extending from the corner of the lip to the
earlobe and the lower edge of the mandible
was determined as the superior and inferior
borders, and the borders of the masseter
muscle as the anterior and posterior borders.
An equal 10-15 Units injection of BTA was
applied to each region from three points in
the most protruding region of the masseter
muscle, within 1 cm of the edges of this
imaginary quadrangular area.
In the cadaveric study of Lee et al. to
investigate the mechanism of paradoxical
masseteric swelling; they found that the
deep inferior tendon localized in the
superficial aponerosis of the masseter
muscle prevented the spread of the toxin to
all of the superficial muscle fibers (18). We
think that in all of the cases presented in this
study, the deep inferior tendon prevented
the spread of the toxin to the superficial
layer.
In the treatment of paradoxical masseteric
swelling, more superficial injections into
the same area are recommended (12, 19).
Biphasic injection techniques, injections at
equal distances both superior and inferior to
the deep inferior tendon, and using
ultrasonography imaging technique during
Gazi Sağlık Bilimleri Dergisi 2023: 8 (1): 108-113 Kazan ve Toprak
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the procedure will prevent possible
complications (12, 13, 20).
CONCLUSION AND
RECOMMENDATIONS
There are many methods for the treatment
of bruxism and BTA injections are very
popular recently. However, physicians who
perform this procedure should be aware of
the possible complications. The presence of
the deep lower tendon is an important
anatomical structure that should not be
ignored in BTA injections. To avoid
complications such as paradoxical
masseteric bulging, we think that injections
should be made concerning at least 3 points
and both deep and superfacial parts of
masseter muscle.
LIMITATIONS
The number of cases we presented and the
fact that all cases were female are
limitations of our study. In future studies,
the number of cases should be increased and
research should be conducted on patient
groups of different genders.
INFORMED CONSENT
Written informed consent was obtained
from all participants who participated in this
study.
AUTHOR CONTRIBUTIONS
Concept – M.E.T., O. K.; Design – M.E.T.,
O. K.; Supervision – M.E.T.; Materials –
M.E.T., O.K.; Data Collection and/or
Processing – M.E.T., O.K.; Analysis and/or
Interpretation – M.E.T., O.K.; Literature
Review – O.K.; Writing – M.E.T., O.K.;
Critical Review – M.E.T.
DECLARATION OF INTERESTS
The authors declare that they have no
competing interest.
FUNDING
The authors declared that this study has
received no financial support.
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