ARUP; ISBN: 978-0-9562121-5-3 - CMBBE 2012 - Cardiff University

5. DISCUSSION
Table1 - Maximum force and average force of tongue and lips
Trial 1 Trial 2 Trial 3
Maximum Force (N) 10.6 11.1 11.1
Maximum force SD 2.5 2.4 2.7
Average Force (N) 9.3 9.0 9.3
Average Force SD 2.6 2.5 2.4
N = Newton; SD= Standard Deviation
Computer modeling is useful tool to study the dynamics of healthy tissues and organs,
as well as to simulate their changes and pathologies (Nazari et al., 2010). The scientific
interest in the orbicularis orbis relates mainly to the understanding of motor aspects of
facial region, such as articulatory production of speech and facial mime (Bucki et al.,
2010; Luboz et al., 2005).
In this study, an initial finite element model of the orbicularis orbis was developed,
simulating the position at rest and the muscle activation. Qualitative tests were
performed to access if the clinically known muscle behavior is appropriately reproduced
by the discrete model. In the next step, the real physical testing situation will be
modeled based on a new MRI with the subject using the insert designed for the force
measurement. The intension is that the information provided by this new geometric
model can be validated with measurements from the lips strength quantitative
evaluation.
The newly developed orbicular oris muscle model allowed the simulation of labial
contraction in a healthy individual and demonstrated realistic features of this structure’s
behavior.
As for the instrument developed to evaluate lips force, it demonstrated to be efficient in
analyzing the force produced by the orbicularis oris using an elliptical shaped insert
which the patient presses the lips to generate a counter-resistance force. The instrument
proved to be of easy handling and wide applicability. During its use, some problems
were detected, being the most relevant the difficulty to standardize and reproduce the
positioning of the subject and the own instrument.
Maximum and average lips forces obtained with FORLAB were similar on the three
trials. The force values were similar to those found by McHenry et al. (1999) for the
lower lip and also to the ones related by Jung et al. (2003).
It is known that when there is a change in structures, organs or systems of the human
body, it is necessary, at first, that the professional responsible for that particular are of
expertise makes an assessment of the conditions of that structure, organ or system, in
order to indicate the best treatment. A proper evaluation is essential for the fast
resolution of the problem.
At the current stage, the geometry used for the model generation does not correspond to
the situation where the insert is positioned inside the mouth of the individual, which
affects the rest position and the behavior of the muscle. The next step, being
implemented by the group, is to develop a new geometric model that includes shape