Page 21 - Dental Technology 12-3

20-22-Thomas Lee article-Q8_6-7-8-Ivoclar.qxd 10/6/2022 8:47 PM Page 2

prosthodontic section 21
DENTAL TECHNOLOGY, JULY-SEPTEMBER 2022

FIG 5 FIG 6 FIG 7

FIG 8 FIG 9 FIG 10

clusal record usually incorporates the use of an anterior discluder
STEP 3 OPTION
For a Standard Functional Mounting,simply place upper study such as a Lucia Jig, leaf gauge, etc.
Since the articulator axis is not the true hinge axis of the patient
model on the Kois Platform with the incisal edge to the 100mm line
on the waxing guide (Figure 7) (New PAL 2.0 Articulator System when using a facebow or Kois DFA, changing Vertical Dimension of
shown). Occlusion (VDO) on the articulator can create positive errors or dis-
The Panadent PAL 2.0 Articulator System with integrated Kois crepancies in the Bite. When changing VDO, it is highly recommend-
ed to take an interocclusal record at the VDO that the restorations,
Platform has same anatomical axis as the full-size articulator and is
designed to implement the ABC’s of Occlusion for General or Digital prostheses, or occlusal splint will be fabricated to reduce positive
Dentistry (Figure 8)! Using the Kois DFA to communicate esthetic errors for less adjustments of the Bite.
and functional information or doing a Standard Functional
CHEWING
Mounting using Fig. 4, Fig. 6, Fig. 5, Fig. 7, Fig. 8 It is important to understand incising and lateral chewing move-
Standard Functional Mounting using the Kois Platform may ments (envelope of function) to simulate more accurate chewing
reduce positive errors for fewer adjustments of opening and closing movements in an articulator. The protrusive pathway(downward
movements of the Axis.
and forward movement of the condyles) together with incisal guid-
ance can have a discluding influence on the distal inclines of the
BITE upper teeth and/or mesial inclines of the lower teeth in incising
All dentists use marking ribbon to mark and adjust any high spots chewing movements (Figure 11). Research shows that the angleof
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to achieve equal contacts of the teeth when the patient bites (MIP). the protrusive pathway ranges from 25 to 75 to an axis-horizontal
However,if the patient has worn or broken teeth,periodontal dis- plane of reference. The protrusive pathway is the only discluding
ease, muscle or TMJ dysfunction, then the patient’s bite (MIP) in factor that can be programmed into an articulator which can be
relation to their jaw position may not be working well and may be communicated with a protrusive interocclusal record to set the artic-
one should consider changing the bite to a new jaw position. ulator. If no protrusive record is taken, it is recommended to set the
o
• Maximal Intercuspal Position (MIP): the best fit of the teeth articulator to a 25 protrusive pathway to create negative errors in
regardless of condylar position. incising chewing movements.
• Centric Relation (CR): a maxillomandibular relationship inde- The Bennett movement (inward movement of the condyles)
pendent of tooth contact. together with canine guidance can have a discluding influence on
• Centric Occlusion (CO): the occlusion (first contact)of oppos- the buccal and lingual cusps of the posterior teeth in lateral chew-
ing teeth when the mandible is in centric relation. ing movements (Figure 12). Research shows that Bennett move-
ment ranges from 0.5mm to 2.5mm with approximately 90% of the
8
It makes anatomical sense to have the jaw in a physiologic posi- population having 1.5mm of Bennett movement or less. It is recom-
tion where the condyles are against the disc orthopedically aligned mended to set the articulator to at least 1.5mm of Bennett move-
in the fossa when all the teeth are occluded (CR+MIP=CO) with ment to create negative errors in lateral Chewing movements.
normal neuromuscular function (Figure 9). It is important to con- Most semi-adjustable articulators incorporate a straight-line
firm that the Centric Relation jaw position is a comfortable, stable, undercompensated Bennett guide “a” (Figure 13) meaning the
and repeatable position. This should involve the use of an orthotic patient can move (curved dotted line) beyond the articulator guide
device that incorporates an anterior deprogrammer (something (solid line) which may create positive errors in lateral chewing
between the anterior teeth) which separates the posterior teeth, movements. The “Immediate Side Shift” articulator in corporate an
relaxes the muscles, and allows the condyles to seat upward and for- over compensated Bennett guide“b” (Figure 13), meaning the
ward against the disc in the fossa (Figure 10) The orthotic device articulator can move (solid “S” lines) beyond the patient’s move-
can be adjusted periodically as healing and remodeling occurs until ments (curved dotted line) which may create negative errors, but
the TM Joints have stabilized. Methods for registering a CR interoc- may also produce flatter anatomy.The Panadent articulator incorpo-