RECORDING OF MASTICATION ANGLES BY PLANAS’S LAWS
Figure 3. The antero-posterior growth is the
movement of mandible to the non-working side
Figure 4. The gliding of the mandible to the
working side causes transversal development
Figure 5.
Growth or expansion
of the maxilla
The gliding of the mandibular condyle and
articular disc complex [2] during the diagono
- transverse movement is the stimulant need
for growth. What is essential for the mandible
antero-posterior growth is the movement of the
mandible to the non-working side (fig 3).
The gliding of the mandible to the working
side causes transversal development (fig 4.)
determined by muscular contraction and
occlusal contacts during mastication (the
stimulants are perceived and transmitted thanks
to a rich periodontal innervation).
Petrovic’s [13] observations after sectioning
the pterygoid muscle (on rats), certify that the
mandible undergoes a “decrease in longitudinal
development and a drop in the number of
mitoses in the growth area”.
The growth of the mandible is obtained using
a system that amplifies the propulsion of the
mandible. In conclusion, immobilizing or limiting
the movements of the mandible can induce a
significant diminution of the mandible size and
the diminution of the mitoses number [3].
STOMA.EDUJ (2014) 1 (2)
Maxillary growth, according to Planas[14, 15],
depends on the friction force that appears in
mastication between the dental articular facets
of the superior and inferior teeth on the working
side [10-15]. The result will be the growth or
expansion of the maxilla in that zone together
with the palatal vault and the floor of the nasal
fossae (fig. 5).
Thus, a circle is created in which the growth
of the mandible determines the growth of the
maxilla. To have physiological masticatory
movements, we need to cause the diagonotransverse movements of the hemi-mandible
to the non-working side and sufficiently intense
dental contacts on the working side.
Murphy [1] explained that the masticatory
cycle evinces overlapping of the terminal points,
irrespective of the mandible trajectory, which
we have also underlined.
In order to consider the masticatory function
correct, it is necessary that the masticatory
angles permit not only an easy lateral movement
of the mandible, but also equal dental contacts.
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