Surgery and Dentistry. We have few publications
in this area but many clinical possibilities which are
tested by some authors. Some clinical applications
target rare diseases, some address very frequent
and challenging problems like bruxism. The aim
of this paper is to present current possibilities with
little evidence-based literature which we have now
and to inspire systematic research.
2. The principle of the method and its history
Botulinum toxin causes presynaptic blockade at the
neuromuscular junction, which has the anatomically
permanent character but due to the growth of new
connections the effect is clinically reversible. 3 The
blockade prevents the transmission of the signal
and the muscle cannot be activated until after three
to four months 3 by which time the sufficient amount
of new synapses has been created to restore the
function of the affected muscle. This formation
mechanism of new synapses connections has
not been exhausted even after a few decades of
repeated treatment on long-term treated patients.
(Fig. 1)
Figure 1. Action of botulinumtoxin (Rowland LP, N Eng J Med.
2002;347(6):382-383).
Originally it was thought that the mechanism
influences the motor function selectively, but now
it is considered proven that the botulinum toxin
reduces the sensitive nerve function as well. 4
Botulinum toxin is supplied to the market by several
manufacturers, however the product molecule
differs fundamentally so that the units of each
product do not interconvert. Therefore different
brands can not be interchanged arbitrarily as
appropriate dosage to potency ratios varies.
The history of the botulinum toxin application in
medicine is quite short. In ophthalmology, the
first patient with strabismus was injected in 1997
by Alan B Scott (San Francisco, CA, USA), who
subsequently also reported the clinical utility. 5 In
plastic surgery, it was used to treat facial asymmetry
by Richard Clark (Sacramento, CA, USA) in 1989. 6
Three years later it was further successfully
elaborated in a study published by the Canadian
couple, ophthalmologist Jean Carruthers and
dermatologist Alistar Carruthers, who observed
that blepharospasm patients after injections around
their eyes and upper face enjoyed diminished
facial glabellar lines. 7 Today the interdisciplinary
knowledge is essential for most applications, and
the subject is thus an example of the necessity of
broader medical education in dentistry to be able
to deploy its full potential. (Table 1)
The precautionary principle, however, is a must
due to the short history of indications alongside
the lack of studies and binding recommendations.
Doctors shall adhere to the principle of prudence to
enhance the safety and satisfaction of patients and
reduce the risk of complications.
Effective applications of botulinum toxin in dentistry and in head and neck surgery
3. Contraindications and systemic complications
The application of botulinum toxin has
contraindications, which are often overlooked.
They include neuromuscular diseases (eg.
Myasthenia gravis), pregnancy, infection at the site
Table 1. Therapeutic uses of botulinum toxin.
Indication
Effectiveness First line treatment medium No low
high Possibly high
medium Possibly low
low-medium No low
low No low
medium-high Possibly Tinnitus low No Decreased or increased position of the upper lip high very likely medium-high
Application into Orbicularis oris muscle high very likely medium-high
Elevation of the mouth corners medium-high very likely medium
Applications to the mimic m. of the lower facial third medium-high Very likely medium-high
Headaches in region m. Occipitofrontalis
BTX for facial asymmetry
Applications to the m. Masseter (mostly bruxism)
Syndrome of temporomandibular joint
Trigeminal neuralgy
Sialorrhoea
Stomatology Edu Journal
Risk of
complications
low-medium
low
201