new simplex

Main ideas and lessons (mounting on a Newlex articulator)

1) Parts and key purpose of the articulator

The articulator is described with these components:

• Lower arm
• Upper arm
• Incisal stem
• Incisal table
• Mounting plate
• Various adjustment screws

Key defining features/uses:

• Mounting plate: used to determine and preserve the occlusal plane, preventing it from drifting during mounting.
• Incisal stem: used to control the vertical dimension, with the incisal pin contacting the incisal table.

2) Alignment requirements before mounting

Before beginning:

• The incisal stem on the incisal table must be aligned.
• The upper and lower arms must be parallel.

3) Mounting plate landmarks (positioning the models)

The mounting plate includes landmarks to position the models consistently:

• Anteroposterior line: centers the model properly.
• Mesiodistal-crossing line: positions the model anteriorly.

The setup relies on intermaxillary records:

• Upper arch: notches made for articulation.
• Lower arch: wax stops.

Wax keys allow the clinician/technician to reposition both models at any moment, so articulation can be reproduced consistently.

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Step-by-step methodology (mounting procedure)

A) Establish and mark the midline and center references

• Draw a midline on the upper model passing through the midpalatal arch.
• Extend it to the back of the base.
• Mark:
  • A reference point at that level
  • The anterior midline, aligned with the patient’s marked midline
• Project the anterior reference toward the anterior edge of the base.
• Use a ruler to join both references:
  • The resulting reference is the center of the model
  • The model center must coincide with the center of the base plate

B) Maintain the occlusal plane while adding plaster/wax stops

• Maintain the occlusal plane at all times.
• Adding plaster to the upper part of the base can destabilize the setup, so:
  • Add wax stops while maintaining the occlusal plane.
• Adapt wax stops so they:
  • Do not modify the occlusal plane
  • Allow correct “basting/casting” so contact is maintained conceptually (“bast must always maintain correct contact”).

C) Prepare plaster and secure retainers before basting/casting

• Before basting:
  • Apply plaster to both upper and lower retainers.
• When mounting another model later:
  • Plaster can be removed from the articulator.

D) Verify upper mounting and incisal pin contact

After mounting the upper model:

• Confirm the cruciate plane has not moved and remains at the anterior level.
• Check the anterior rim is limited by the distal line.
• Confirm the middle part of the rim matches the middle part of the footplate.

Incisal pin verification

• The incisal pin must be in contact with the incisal table.
• This contact provides the patient’s vertical dimension.
• The incisal pin should remain in constant contact (control mechanism).

Special note for Din Simplex articulators

• The incisal pin may not have a built-in “zero line” reference.
• A “zero line” must be created (details deferred in the source), but constant contact must still be maintained.

E) Use limitations: what movements are reliable

• The articulator is described as a class two articulator.
• It can open/close and allow lateral movements, but:
  • Lateral movements are not used because they do not reliably resemble TMJ movements.
• If lateral movements are needed:
  • Use semi-adjustable articulators.

F) Mounting the lower model: wax management and base fixation

When fixing the lower model:

• Use a different color of wax at:
  • The rims
  • The baseplates
  • The models
  • Between both models

The video warns about premature base contact:

• Especially posteriorly, early base contact can alter the intermaxillary relationship.
• If height adjustment is considered:
  • Lowering one base to avoid contact can introduce articulation error (because it changes relationships).

G) Prevent common articulation/casting errors

1) Incorrect fixation of bases - Error: if bases/records/baseplates are not fixed properly, plaster addition can allow movement. - Consequence: records/intermaxillary relationship may change.

2) Exaggerated plaster raising the incisal pin - Error: increasing plaster near the lower model’s base can raise the incisal pin/stem. - Consequence: mis-seating of the incisal mechanism. - Fix: - Cut a part of the base if needed. - Keep base height only around 1.5 cm.

H) Casting / make retentions and finalize plaster

• Make retentions in the lower base:
  • With pliers or by forming an X-shape.
• Proceed with casting (described sequence includes plaster and application details as shown in the video):
  • Cover both lower and upper parts of the branch as described.

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Tooth arrangement and control of occlusal curves

1) Role of the articulator plate

The plate helps control curvatures in:

• Anteroposterior direction: Spee (SPIe) curve
• Frontal direction: Wilson curve

2) Occlusal plane contact rules used to build the curves

How different teeth relate to the occlusal plane:

• Central incisor: touching the occlusal plane.
• Lateral incisor: positioned ~1 mm above the occlusal plane (the numeric rule is emphasized even if subtitles show “touching”).
• Canine: used as a reference supporting the ~1 mm relationship.

Premolars

• Second premolar: both cusps touch the occlusal plane.
• First premolar (offsets from the occlusal plane):
  • Mesiobuccal cusp: touches the occlusal plane
  • Distal palatal cusp: 0.5 mm from the occlusal plane
  • Mesiobuccal cusp: 1 mm from the occlusal plane
  • Buccal cusp: 1.5 mm from the occlusal plane

Molars

• No cusps touch the occlusal plane.
• The curve is described as already ascending.

3) Wilson curve purpose and how it is seen

• Wilson curve is studied at the frontal level.
• It sets relative distances of palatal cusps vs buccal cusps to the occlusal plane.
• Visual logic given:
  • Palatal cusps of upper molars are closer to the occlusal plane.
  • Buccal cusps are higher.
• The curve changes direction across tooth groups:
  • In second premolars: both cusps contact the occlusal plane.
  • In first premolars: curvature is described as “reversed” (palatal cusps are raised relative to the occlusal plane).

4) Bilateral balanced occlusion and eccentric movements (complete edentulism)

For complete edentulism, the occlusion is described as:

• Bilaterally balanced occlusion
• With contact on both:
  • Balancing side
  • Working side

During:

• Excursive movement
• Protrusive movement
• Lateral movement

Anterior teeth

• Remain free of contact to help stabilize a removable complete denture.

The curves (SPIe / Wilson) are presented as mechanisms to avoid interferences, particularly on the working side during lateral movements.

5) Verification after tooth arrangement

• Check that the incisal pin properly contacts the incisal table.
• If not:
  • The vertical orientation has been altered from the specified setup.

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Clinical/lab troubleshooting: detecting vertical dimension distortion

What can go wrong

A case is described where a removable partial denture model initially arrived correct, but the final check failed:

• Assembly was correct initially (incisal pin contacted incisal table laterally during lab setup).
• In the final model, incisal pin contact did not occur properly on the articulator.
• Interpretation:
  • Vertical dimension was distorted or manipulated.
• The side view shows the incisal point separated from the incisal table.
• Possible reasons:
  • Teeth not worn down correctly at the “heel,” or incorrect tooth positioning.

How the “reference/no-mark” problem is solved

With this articulator type (compared to semi-adjustable ones):

• The incisal stem may lack reference marks and the “zero line” is not provided.

Proposed fix

• Create a small notch at the top of the stem using a carbide disc.
• The notch becomes the reference to:
  • Ensure both branches are parallel (upper and lower)
  • Enable correct mounting procedures

How to use the reference on lab jobs

• The lab is said to send models with the correct vertical dimension because it is checked.
• When receiving the job:
  • Reposition the notch/reference to the correct position (e.g., flush with the upper ramus).
• Then:
  • Verify tooth arrangement relative to vertical dimension.
• If vertical dimension has already changed, the patient test would be time-consuming, so repeated returns should be avoided.

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Speakers / sources featured

Speaker

• The subtitle stream does not provide a clear personal name.

Organizations / brands mentioned

• Newlex / Din Simplex articulator
• TMJ (temporomandibular joint)
• Wilson curve
• Spee (SPIe) curve
• Facebook page: “jil odontólogo”

External written sources

• No external studies or written sources are cited by name in the subtitles.