21.occlusal schemes monoplane with balancing ramps

21. Occlusal Schemes - Lingualized vs 21. Occlusal Schemes - Lingualized vs Monoplane - Neutrocentric ConceptMonoplane - Neutrocentric Concept

John Beumer III, DDS, MSJohn Beumer III, DDS, MSandand

Michael Hamada DDSMichael Hamada DDSDivision of Advanced Prosthodontics, Division of Advanced Prosthodontics, Biomaterials and Hospital DentistryBiomaterials and Hospital Dentistry

UCLA School of DentistryUCLA School of Dentistry

This program of instruction is protected by copyright ©. No portion of This program of instruction is protected by copyright ©. No portion of this program of instruction may be reproduced, recorded or transferred this program of instruction may be reproduced, recorded or transferred by any means electronic, digital, photographic, mechanical etc., or by by any means electronic, digital, photographic, mechanical etc., or by any information storage or retrieval system, without prior permission.any information storage or retrieval system, without prior permission.

Lingualized Opposing Monoplane Neutrocentric Lingualized Opposing Monoplane Neutrocentric ConceptConcept

Lingualized Opposing Monoplane Lingualized Opposing Monoplane Neutrocentric ConceptNeutrocentric Concept

Begin by positioning a zero degree protrusive insert. Check Begin by positioning a zero degree protrusive insert. Check to ensure that the incisal guide pin is set at zero and in to ensure that the incisal guide pin is set at zero and in contact with the incisal guide table.contact with the incisal guide table.

Protrusive insertProtrusive insert

Protrusive Protrusive insertinsert

Zero Zero settingsetting

Monoplane Occlusion – Neutrocentric ConceptMonoplane 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.

Mark the casts indicating midline, crest of the ridge, and the retromolar pad. These landmarks will be used to check your denture setup.

MaxillaMidlineAnterior land

MandibleRidgeRetromolar pad

Cast LandmarksCast Landmarks

As previously mentioned (13c, 1a), the wax rim is ideally contoured on 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 the patient and used to mount the upper cast with a facebow transfer record. When the lower cast is mounted on the articulator with a centric record. When the lower cast is mounted on the articulator with a centric relation record, the plane of occlusion is readily seen.relation record, the plane of occlusion is readily seen.

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

Setting the Maxillary Anterior TeethSetting the Maxillary Anterior Teeth

Midpoint of Midpoint of retromolar retromolar

padpad

Midpoint of Midpoint of retromolar retromolar

padpad

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.


Mark indicating midpoint of the retromolar pad


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).


Note the angulations of the anterior teeth in relation to the occlusal plane when viewed in profile.

Occlusal Occlusal planeplane


““Toed-in” PositionToed-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.

Setting Mandibular Anterior TeethSetting 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.

Magnitude of horizontal overlap?

Setting Mandibular Anterior TeethSetting Mandibular Anterior Teeth

In Class II patients the mandible tends to travel farther anteriorly in function than the typical Class I patient and consequently more horizontal overlap is necessary to allow for this functional movement.

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 IClass I Class IIClass II

Class IIIClass III

Setting the Mandibular Anterior TeethSetting the Mandibular Anterior Teeth

The horizontal overlap should be consistent throughout the anterior region. In this setup it is about 1.5 mm.

Setting the Mandibular Anterior TeethSetting 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.


Background - Setting the posterior teeth The number and combination of the denture teeth utilized varies depending on the arch length of the patient.

The mandibular occlusal table should end prior to the ascending ramus.

The distal surface of most posterior maxillary denture tooth should extend one half 1-2mm distal to the most posterior mandibular denture teeth.


Position the posterior mandibular teeth over the crest of the ridge. Check to ensure they are set to a flat plane and on the plane of occlusion.Since there is no vertical overlap of the anterior teeth, both the anterior and the posterior teeth are set on the plane of occlusion.Make corrections as necessary


Position the maxillary posterior teeth. The tips of the maxillary lingual cusps should contact the central groove of the mandibular posterior teeth as shown.


By properly centering the lingual cusps of the maxillary teeth over the central grooves of the mandibular teeth the horizontal overlap should be ideal and should be sufficient to prevent biting of the cheek and corner of the mouth.

Horizontal overlap


Note that the Note that the maxillary premolars in maxillary premolars in the of the Ivoclar the of the Ivoclar Ortholingual denture Ortholingual denture teeth are of sufficient teeth are of sufficient length to harmonize length to harmonize with the cuspid. with the cuspid.


Verify 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.

Note that the occlusal plane is parallel to the mandibular denture foundation area.


Reestablish centric Reestablish centric contactscontacts as necessary by as necessary by manipulating the manipulating the mandibular posterior mandibular posterior teeth. Make sure that the teeth. Make sure that the incisal guide pin incisal guide pin maintains contact with maintains contact with the incisal guide table the incisal guide table when you have when you have completed this step.completed this step.

Lingualized Opposing Monoplane Lingualized Opposing Monoplane

If the patient presents with steep condylar guidance it may be If the patient presents with steep condylar guidance it may be useful to add balancing ramps to overcome Christiansen’s useful to add balancing ramps to overcome Christiansen’s phenomenon to idealize the stability of the mandibular denture.phenomenon to idealize the stability of the mandibular denture.

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21.occlusal schemes monoplane with balancing ramps