Posterior tooth selection

Question 1

What are the considerations that you should make for posterior tooth selection?

Answer 1

• resorbed or flabby ridges
• physical condition of the patient
• patients with parafunctional habits (clenching or bruxing)
• previous denture occlusion
• immediate dentures
• ridge relationship
• opposing dentition

Question 2

What kind of posterior tooth for a complete denture is indicated when there is poor record base stability?

Answer 2

lower cusp height

Question 3

When is higher cusp height indicated for patients with resorbed or flabby ridges? What kind of occlusal scheme can you recommened in these cases?

Answer 3

• patients that have retained excellent tongue coontrol and a reasonably stable denture base
• if they are vertical chewers rather than wide envelope grinders- they will often prefer and be able to handle cusp-fossa teeth

They are ideal candidate for lingualised occlusal schemes

Question 4

What occlusal scheme would you recommend to patients with poor neuromuscular control and why?

Answer 4

Monoplane occlusal scheme
this is because they have difficulty tolerating anatomic occlusions

Question 5

What is the best occlusal scheme for patients with parafunctional habits such as anxiety, bruxing or grinding? Justify your reason

Answer 5

• Monoplane occlusal scheme
• this is because these behaviours are often traumatic to the supporting structures when anatomic posterior denture teeth are used

Question 6

How can you use a patients previous denture occlusion to guide your decision for posterior tooth selection ?

Answer 6

if the previous denture has anatomic teeth which have not been severly worn and the alveolar ridges are not severely worn then anatomic teeth can be used.

If the previous denture has been worn flat then non-anatomic teeth are the better choice

Question 7

What considerations for posterior teeth selection should you make for patients with a class II relationships?

Answer 7

• usually requires non anatomic posterior teeth
• or a a minimum, mandibular teeth should have an open fossa which permits multiple contact positions (anterio-posterior) without any occlusal interference

Question 8

What occlusal scheme should you recommend for immediate dentures and why?

Answer 8

• a non interscuspated denture tooth form like lingualised or monoplane
• gives freedom for the patient to re-establish correct maxilla-mandibular relationship

Question 9

What posterior tooth selection should you make for a single denture opposing natural dentition?

Answer 9

Anatomic teeth- teeth with cusps

Question 10

In a case where the maxillary denture opposes mandibular natural teeth, what kind of occlusal scheme should you use?

Answer 10

the mandibular cusps should be the functional cusps opposing the maxillary fossae

Question 11

What are the indications for use of non anatomic posterior teeth?

Answer 11

• poor residual ridges
• poor neuromuscular control (parkinsons, bruxists)
• previous ly successful with monoplane denturs or severely worn occlusion on previous denture
• arch discrepancies- class II or class III or cross bite
• immediate dentures - except when opposing natural dentition
• potential poor follow up

Question 12

What are the indications for use of anatomic posterior teeth?

Answer 12

• good residual ridges
• well coordinated patient
• previously successful with anatomic dentures
• dentures that oppose natural dentition
• when lingualised occlusion is desired

Question 13

What are the advantages of non-anatomic posterior teeth (monoplane occlusion) ?

Answer 13

• reduction of horizontal forces
• centric occlusion can be developed as an area instead of a point
• freedom from movement in centrci
• can develop stable occlusion despite arch alignment discrepancies
• easily adapted to situations prone to denture base shifting
• easy to set and adjust teeth

Question 14

What are the disadvantages of non anatomic (monoplane occlusion)?

Answer 14

• no vertical component (cusp) to aid shearing during mastication
• occlusal adjustment impairs efficency unless spillways and cutting edges are restored
• patients may complain of lack of positive intercuspation position
• somewhat poor aesthetically

Question 15

What are the advantages of a balanced occlusion?

Answer 15

• definite point of intercuspation may be developed
• aesthetically similar to natural dentition
• tooth to tooth an cusp to cusp balanced occlusion can be achieved
• maintains shearing ability after moderate wear

Question 16

What are the disadvantages of balanced occlusion?

Answer 16

• difficult to set
• less adaptable to arch relation discrepancies (e.g. class II or III)
• horizonal force development due to cusp inclinations
• harmonious balanced occlusion is lost with denture base settling
• requires frequent follow ups and may require frequent relines to maintain proper occlusion

Question 17

What type of occlusal scheme does lingualised occlusion belong to?

Answer 17

bilaterally balanced occlusal schemes

Question 18

What type of teeth are used in lingualised occlusion?

Answer 18

• anatomic teeth in maxilla which oppose
• flat cusped or shallow cusped mandibular teeth

Question 19

What are the indications for use of lingualised occlusion?

Answer 19

• high aesthetic demands
• severe mandibular ridge atrophy
• displaceable supporting tissues
• malocclusion
• previously successful denture with lingualised occlusion

Question 20

What are the advantages of lingualised occlusion?

Answer 20

• good aesthetics
• freedom of anatomic teeth
• potential for bilateral balance
• centralises vertical forces
• minimises tipping forces
• facilitates bolus penetration (motar and pestle effect)