1) The neutrocentric concept assumes the plane of occlusion is parallel to the denture foundation and not dictated by condylar inclination, with no vertical overlap or compensating curves. 2) When setting the teeth, the maxillary anteriors are positioned so their incisal edges and the midpoint of the retromolar pads define the flat occlusal plane. 3) Both the anterior and posterior teeth on the dentures are set on this flat occlusal plane with about 1/3 horizontal overlap of the posterior teeth.

1. Occlusal Schemes - Monoplane
Neutrocentric Concept
John Beumer III, DDS, MS
and
Michael Hamada DDS
Division of Advanced Prosthodontics
UCLA School of Dentistry
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2. Monoplane Occlusion – Neutrocentric Concept
Background
This concept of occlusion assumes that the anterior-posterior plane of
occlusion should be parallel to the denture foundation area and not dictated
by condylar inclination.
The plane of occlusion is completely flat and level. There is no curve of
Wilson or Curve of Spee (compensating curve) incorporated into the set up.
There is no vertical overlap of the anterior teeth.
When using this concept of occlusion the patient is instructed not to incise
the bolus. With this tooth arrangement DeVan noted that “the patient will
become a chopper, not a chewer or a grinder.”
When setting these teeth the horizontal and lateral condylar guidances
should be set at zero.

3. Monoplane Occlusion – Neutrocentric Concept
Zero
setting
Protrusive inserts
Protrusive
insert
Begin by positioning a zero degree protrusive insert, and check
to ensure that the incisal guide pin is set at zero and in contact
with the incisal guide table.

4. Cast Landmarks
Mark the casts indicating midline, crest of the ridge, and the
retromolar pad. These landmarks will be used to check your
denture setup.
Maxilla Mandible
Midline Ridge
Anterior land Retromolar pad

5. Cast Landmarks - Maxilla
Anterior land
Incisive
papilla
Midline

6. Cast Landmarks -Mandible
Midpoint of
retromolar pad
Mark on land
Land
indicating the
midpoint of the
Lines indicating the
retromolar pad
crest of the ridge

7. Setting the Maxillary Anterior Teeth
As previously mentioned (13c, 1a), the wax rim is ideally contoured on
the patient and used to mount the upper cast with a facebow transfer
Midpoint of Midpoint of
retromolar retromolar
pad pad
The three landmarks used to identify the plane of occlusion are:
The midpoint of the retromolar pads bilaterally as previously marked on
the mandibular cast.
The incisal edge of the maxillary central incisors

8. Setting the Maxillary Anterior Teeth
Mark indicating midpoint
of the retromolar pad
To set the remaining maxillary
anterior teeth a clear glass or
plastic slab is positioned on the
mandibular record base to
represent the plane of occlusion.

9. Setting the Maxillary Anterior Teeth
Soften some baseplate wax and attach some to the ridge lap
portion of the other maxillary central incisor and attach it to
the record base as shown. Set the lateral incisors and
cuspids as shown previously (Section 13c, 1a Lingualized
occlusion).

10. Setting the Maxillary Anterior Teeth
Occlusal
plane
Note the angulations of the anterior teeth in relation to the
occlusal plane when viewed in profile.

11. Setting the Maxillary Anterior Teeth
“Toed-in” Position
Note how the cervical and incisal edges of the cuspid are aligned
vertically (yellow line). The facial surface of the cuspid however, is
canted inward and appears “toed in” (red line) due to the prominence of
the cervical area of the tooth (yellow arrow). The centrals and laterals
are inclined slightly towards the distal.

12. Setting Mandibular Anterior Teeth
Amount of vertical overlap
When using a neutrocentric concept of occlusion is no
vertical overlap should be incorporated into the set up.

13. Setting Mandibular Anterior Teeth
Magnitude of horizontal overlap?
In Class II patients the
mandible tends to travel farther
anteriorly in function than the
typical Class I patient and Class I Class II
consequently more horizontal
In contrast Class III patients often demonstrate little or no
anterior movement of the mandible during function.
Consequently, little or no horizontal overlap is developed
in the set up.
Class III

14. Setting the Mandibular Anterior Teeth
The horizontal overlap should be consistent throughout the
anterior region. In this setup it is about 1.5 mm.

15. Setting the Mandibular Anterior Teeth
Positions of the anterior teeth. The lateral incisors should
be placed similar in angulation and position to the central
incisors. Note that the cuspids are towed out at the
cervical.

16. Monoplane Occlusion – Neutrocentric Concept
Background - Setting the posterior teeth

17. Monoplane Occlusion – Neutrocentric Concept
l Position the posterior
mandibular posterior teeth over
the crest of the ridge. Check to
ensure they are set to a flat
plane and on the plane of
occlusion.
l Make corrections as necessary
Occlusal
Plane Since there is no vertical
overlap of the anterior
teeth all of the mandibular
teeth are on the plane of
occlusion.

18. Monoplane Occlusion – Neutrocentric Concept
l Since there is no vertical overlap of the anterior teeth both
the anterior teeth and the posterior teeth are on the plane of
occlusion.
Make corrections as necessary.

19. Monoplane Concept – Neutrocentric Concept
l Position the maxillary posterior teeth.

20. Monoplane Occlusion – Neutrocentric Concept
l Check the horizontal overlap of the
posterior teeth. The overlap should be at
least one third of the width of the occlusal
surface and be sufficient to prevent biting
of the cheek and corner of the mouth.
Horizontal overlap

21. Monoplane Occlusion – Neutrocentric Concept
l Note that the premolar in
the of the Ivoclar
Orthoplane tooth form is
of sufficient length to
harmonize with the
cuspid. In addition the

22. Monoplane Occlusion – Neutrocentric Concept
The flatness of the maxillary premolars is provided by the
flat buccal and lingual cusps. Note that in this set up both
lingual and buccal cusps contact the plane of occlusion.

23. Monoplane Occlusion –Neutrocentric Concept
l With this occlusal scheme the plane of occlusion should
be parallel to the denture foundation area.

24. Monoplane Occlusion –Neutrocentric Concept
l Verify again that all the maxillary teeth, with the exception
of the lateral incisors and perhaps the cuspids, are on the
plane of occlusion. Make corrections by manipulating the
maxillary teeth. When you have completed this step,
thoroughly cool the wax before proceeding to the next step.

25. Monoplane Occlusion – Neutrocentric Concept
l Reestablish centric contacts
as necessary by manipulating
the mandibular posterior
teeth. Make sure that the
incisal guide pin maintains
contact with the incisal guide
table when you have
completed this step. While
performing this step make
sure you do not alter the
horizontal overlap of the
posterior teeth.

26. Monoplane Occlusion- Neutrocentric Concept
l Note Christiansen’s
phenomenon, or the
separation between the
posterior teeth in the
20 degrees
protrusive position. If the
patient presents with
steep condylar
inclination the posterior
discrepancy in excursion
may become significant.
30 degrees

27. Monoplane Occlusion- Neutrocentric Concept
l The steeper the
condylar inclination
the greater the
posterior discrepancy
in excursion and the
greater the need for
balancing ramps, and
so in this patient,
balancing ramps were
added to improve the
stability of the lower
denture.

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