Anatomy - Complete Dentures

Question 1

What are the limiting areas of the maxilla?

Answer 1

Labial and buccal frenum
Hamular notch
Vibrating line

Question 2

How is the incisive papilla used as a landmark

Answer 2

Biometric guide for positioning upper incisors

They should be placed 8-10mm anterior to the incisive papilla

Question 3

Where is the vibrating line?

Answer 3

• at the junction of the soft and hard palate extending from one hamular notch to the other and 2mm in front of the palatine fovea

Question 4

Where should the posterior border of the upper denture extend to? And why?

Answer 4

The vibrating line

- because the tissue is compressible but isn’t displaceable, thus allowing retention of the denture

Question 5

How do we check correct extension of the upper denture at wax try in?

Answer 5

• the tray should be retentive (without material)
• the tray should pop when removed
• the tray remains retentive even when the pt says “ahh”

Question 6

What is the post dam?

Answer 6

Posterior border of the upper denture that sits at the vibrating line

Question 7

List the features of a post dam

Answer 7

Elevated lip of acrylic
Extends from one hamular notch to the other
Narrower in the centre and widens towards the lateral edges and narrows as it approaches the hamular notch (it is never >4-6mm at the widest part

Question 8

Why isn’t the vibrating line in a straight line?

Answer 8

Due to the projection of the posterior nasal spine

Question 9

What is the primary support bearing area of the lower denture?

Answer 9

Buccal shelf

Question 10

What are the primary support bearing areas of the maxilla

Answer 10

The posterior aspect of the palate

The posterolateral aspect of the residual alveolar ridge

Question 11

What are the secondary support bearing areas of the maxilla

Answer 11

Palatal rugae area

Maxillary tuberosities

Question 12

List the relief areas for the upper denture

Answer 12

Incisive papilla
Fovea palatine
Mid palatal suture (raphe)
Palatal tori if present

Question 13

What are the functions of the posterior palatal seal?

Answer 13

• Retention of the denture
• Prevents food accumulation under the denture base
• Compensation for polymerisation shrinkage
• Reduces the tendency for a gag reflex

Question 14

What are the limiting structures of the mandible

Answer 14

• Labial and buccal frenum
• Labial sulcus
• Retromolar pad

Question 15

What is the retromolar fossa

Answer 15

Triangle shaped soft tissue pad at the distal aspect of the lower ridge which forms the posterior seal of the lower denture

Question 16

How much coverage of the retromolar bad is required

Answer 16

2/3 the length

Question 17

What is the importance of the retromylohyoid fossa?

Answer 17

Provides stability to the denture by preventing lateral movements

Question 18

What is the primary support bearing areas of the lower denture?

Answer 18

Buccal shelf

Question 19

What is the secondary support bearing areas of the lower denture?

Answer 19

Residual alveolar ridge

Question 20

What areas require relief in the lower denture?

Answer 20

Mylohyoid ridge
Mental foramen
Torus mandibularis

Question 21

Why does the Mylohyoid ridge require relief?

Answer 21

The overlying mucosa is thin and easily traumatised

Question 22

Why does the mental foramen require relief? When is this especially important?

Answer 22

When it lies superficially in order to prevent paraesthesia

More resorption = more superficial

Question 23

Why do tori have to be relieved in the denture base?

Answer 23

Due to thin overlying mucosa

Question 24

What are the management options for a patient with tori who needs complete dentures

Answer 24

Relief
Use of resilient liners
Surgical removal

Question 25

When may surgery of tori be indicated?

Answer 25

If it is large enough to impede construction of a prosthesis
It interferes with occlusion
The overlying mucosa is traumatised

Question 26

What are limiting structures?

Answer 26

Structures which guide the position we want to extend the dentures but not encroach upon to allow maximum retention, stability and support

Question 27

What are support bearing areas?

Answer 27

The load bearing structures of the denture
These structures are able to withstand forces occurring during function and the denture should be designed to maximise this

Question 28

What are relief areas?

Answer 28

Structures which require relief because they either resorb under constant load, they have thin overlying mucosa or they have fragile structures within e.g. nerves