Dentaltown June 2024 - 42

CONTINUING EDUCATION
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fovea
palatinae
" ah-ah-ah-ah " sounds and observe the movable
soft palate move up and down. The junction of
the movable and immovable soft palates, the
vibrating line, can be seen and marked.
Sometimes, the movable soft palate moves
minimally, making finding the junction challenging.
It is recommended to use magnification
when locating and marking the vibrating line
intraorally. The fovea palatinae-indentations
near the midline of the palate formed by a coalescence
of several mucous gland ducts-can be
used as a guide for the location of the vibrating
line (Fig. 6). They are always present in the soft
palate (posterior to the hard palate) and are usually
but not always anterior to the vibrating line.
The nose-blowing technique can also be
used as a guide to locate the vibrating line. The
patient's nose is held closed, the patient blows
their nose with their mouth open, and the
movable soft palate moves down (Fig. 7). When
using this technique, some of the immovable soft
palatal tissues are displaced, so this does not
accurately show the location of the vibrating line;
this shows the clinician approximately where the
vibrating line is, and the patient can next repeat
the " ah-ah-ah-ah " sounds so the vibrating line
can be detected and marked.
Note the maxillary denture posterior
extension on the master cast: The denture base
should extend posteriorly to the vibrating line
and the hamular notches. The dentist should
mark these landmarks on the master cast to
accurately show this denture's posterior extension
to the lab. The lab technician should use this
information to create a post dam on the maxillary
denture, creating a seal across the posterior
of the maxillary denture.
Mandibular denture posterior extension:
The posterior extension of the mandibular denture
should rest on the retromolar pads, which
are primary support areas for the mandibular
denture. The retromolar pads are palpable,
soft, compressible, nonkeratinized tissue at the
posterior end of the mandibular alveolar ridges.
After the loss of the molars, the bony ridges
remodel and usually resorb. The pads are important
landmarks for the posterior extension of the
denture and the occlusal plane level of the denture
teeth. The denture should cover two-thirds
of the pads, with the posterior denture extension
in the upper one-third of the pads.
To locate the retromolar pads, run a finger along
the alveolar ridge and feel the pad at the distal
end of the residual ridge. The pads can be marked
with indelible ink, and the impression tray can be
tried into the mouth to verify that the posterior
extensions of the tray will cover the pads so the
impression will accurately record them.
Impression technique for the edentulous
maxilla: Mix light-body alginate impression
material and place in a syringe; mix heavy-body
impression material and place in an impression
tray. Inject the syringe material into the hamular
notches and vestibules (Fig. 8), ensuring these
areas are recorded in the impression. Seat the
tray (Fig. 9) and ensure the borders of the impression
are border-molded.
Border molding of the maxillary impression
simulates muscle function and replicates the
shape and size of the vestibules. This is accomplished
by manipulating the lip and cheek
muscles adjacent to the final denture borders.
Pull straight down on the vermilion border of
the upper lip at the philtrum (Fig. 10). Massage
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Dentaltown June 2024

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