View
240
Download
2
Category
Preview:
Citation preview
22. Criteria for Posterior Tooth Selection22. Criteria for Posterior Tooth Selection
Michael Hamada DDSMichael Hamada DDSandand
John Beumer III, DDS, MSJohn Beumer III, DDS, MSDivision 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.
14. Posterior Tooth Selection14. Posterior Tooth SelectionLingualizedLingualized
Lingualized vs
monoplane
Monoplane Monoplane AnatomicAnatomic
Semi-anatomicSemi-anatomic
14. Posterior Tooth Selection14. Posterior Tooth Selection
Criteria Resorbed or flabby ridges Physical condition of the patient Patients who clench or brux Previous denture occlusion Ridge relationship Immediate dentures
14. Posterior Tooth Selection14. Posterior Tooth SelectionResorbed or flabby ridgesSuch conditions, as demonstrated in these two patients, make it difficult to obtain accurate intraoral records and permit movement of the denture bases during function. The poorer the record base stability, the less cusp height is indicated.Exception: Some patients with highly resorbed ridges retain superb tongue control and a reasonably stable denture base. If they are vertical chewers, rather than wide envelope grinders, they will prefer and be able to handle cusp fossa teeth. Such patients are ideal candidates for lingualized occlusal schemes.
14. Posterior Tooth Selection14. Posterior Tooth Selection
Patients with poor neuromuscular control have difficulty accommodating to anatomic occlusions. They are best served with monoplane occlusal schemes.
Physical condition of the patient
Chronic bruxers and grindersChronic bruxers and grinders
14. Posterior Tooth Selection14. Posterior Tooth Selection
Anxious, nervous individuals are more apt to brux, which can be especially traumatic to the supporting structures when anatomic posterior denture teeth are used. They are best served with monoplane occlusal schemes.
Previous denture occlusionPrevious denture occlusion
14. Posterior Tooth Selection14. Posterior Tooth Selection
If the present dentures have anatomic teeth which have not been severely ground or worn and the alveolar ridges are not severely resorbed, anatomic teeth can be used. If the existing denture teeth have been worn flat, nonanatomic teeth may be a better choice.
Ridge relationshipRidge relationship
14. Posterior Tooth Selection14. Posterior Tooth Selection
A skeletal class II relationship requires nonanatomic posterior teeth or cusp to open fossae teeth which permit multiple contact positions without occlusal interferences.
When the greater width of the mandibular arch requires a crossbite, nonanatomic posterior teeth are often used or cusp-fossae with the upper buccal cusps opposing the lower fossae.
Immediate denturesImmediate dentures
14. Posterior Tooth Selection14. Posterior Tooth Selection
Many dentulous patients, especially those with severely worn dentitions, have a discrepancy between ICP (intercuspal position) and RCP (retruded cuspal position ie centric jaw relation).
Removal of the natural teeth will permit and encourage a retrusive shift in mandibular posture. If so cusp fossae or monoplane posterior denture teeth should be used.
Immediate denturesImmediate dentures
14. Posterior Tooth Selection14. Posterior Tooth Selection
A single denture opposing natural dentition will require cusp teeth. Since artificial teeth have their own morphology they do not occlude well against natural teeth unless the natural teeth are recontoured via enameloplasty to better receive the prosthetic teeth.
In the case of maxillary denture opposing mandibular natural teeth the most likely, practical occlusal scheme will use the mandibular buccal cusps as the functional cusps opposing the maxillary fossae
ChoicesChoicesLingualizedLingualized
14. Posterior Tooth Selection14. Posterior Tooth Selection
ChoicesChoicesSemi-anatomicSemi-anatomic
14. Posterior Tooth Selection14. Posterior Tooth Selection
ChoicesChoicesLingualized vs MonoplaneLingualized vs Monoplane
14. Posterior Tooth Selection14. Posterior Tooth Selection
ChoicesChoicesMonoplaneMonoplane
14. Posterior Tooth Selection14. Posterior Tooth Selection
ChoicesChoicesAnatomicAnatomic
14. Posterior Tooth Selection14. Posterior Tooth Selection
Good Residual Ridges Well Coordinated
Patient Previously successful
with anatomic dentures Denture opposes
natural dentition When “Lingualized”
occlusion is desired
Poor Residual Ridges Poor Neuromuscular
control (Bruxers, CP etc.) Previously successful
with Monoplane Dentures or Severely worn occlusion on previous denture
Arch discrepancies– Class II or III or Cross-bite
Immediate Dentures– except when opposing
natural dentition Potential poor follow-up
Monoplane Occlusion Anatomic Denture TeethIndications for ApplicationIndications for Application
No vertical component to aid in shearing during mastication
Occlusal adjustment impairs efficiency unless spillways and cutting edges restored
Patients may complain of lack of positive intercuspation position
Somewhat esthetically limited (don’t look like natural teeth)
Reduction of horizontal forces
CR can be developed as an area instead of a point
Freedom of movement Can develop solid
occlusion despite arch alignment discrepancies
Easily adapted to situations prone to denture base shifting
Easy to set and adjust teeth
Advantages DisadvantagesMonoplane OcclusionMonoplane Occlusion
Difficult to set Less adaptable to arch
relation discrepancies Horizontal force
development due to cusp inclinations
Harmonious balanced occlusion is lost with denture base settling
Requires frequent follow-up and may require more frequent relines to maintain proper occlusion
Definite point of positive intercuspation may be developed
Esthetically similar to natural dentition
Tooth-to-tooth and cusp-to-cusp balanced occlusion can be achieved
Maintains some shearing ability after moderate wear
Advantages DisadvantagesAnatomic OcclusionAnatomic Occlusion
Good esthetics Freedom of non-
anatomic teeth Potential for bilateral
balance Centralizes vertical
forces Minimizes tipping forces Facilitates bolus
penetration (mortar and pestle effect)
High esthetic demands Severe mandibular ridge
atrophy Displaceable supporting
tissues Malocclusion Previous successful
denture with Lingualized Occlusion
Indications for use AdvantagesLingualized OcclusionLingualized Occlusion
Recommended