retention

Question 1

define denture retention?

Answer 1

resistance to vertical displacement (lifting away from tissues)

Question 2

retention can be achieved by mechanical, muscular or physical forces, describe how it is achieved mechanically?

Answer 2

via clasps engaging undercuts below the bulbous part of the tooth

Question 3

retention can be achieved by mechanical, muscular or physical forces, describe how it is achieved physically?

Answer 3

via mucosal coverage
adhesion and cohesion- surface forces of saliva on denture and mucosa
atmospheric - resistance to displacing forces

Question 4

what are the 2 classifications of retention?

Answer 4

direct and indirect

Question 5

define direct retention?

Answer 5

resistance to VERTCIAL displacement of denture

Question 6

define indirect retention?

Answer 6

resistance to ROTATIONAL displacement of denture

Question 7

what is the principal method of retention?

Answer 7

clasps

Question 8

name the two types of retentive clasps?

Answer 8

oclusally approaching or gingival approaching

Question 9

how long should a retentive claps be?

Answer 9

at least 15mm

Question 10

which type of retentive claps is used for anteriors, canines and premolars?

Answer 10

gingival approaching

Question 11

which type of retentive claps is used for molars?

Answer 11

oclusally approaching

Question 12

in order to utilise an undercut for retention it should be at least what depth?

Answer 12

0.25mm

Question 13

which part of the retentive arm will engage the undercut?

Answer 13

the terminal 1/3 end of the arm

Question 14

what prevents tooth movement when the retentive clasp arm goes over the bulbosity ?

Answer 14

reciprocation

Question 15

is the reciprocal arm on the buccal or lingual of the tooth?

Answer 15

lingual

Question 16

what is the most desirable pattern of retention?

Answer 16

triangular

Question 17

what is used in free end saddle designs to prevent stress on the last abutment tooth?

Answer 17

stress relieving clasp system RPI

Question 18

what does the stress relieving clasp system RPI consist of?

Answer 18

occlusal rest
proximal plate adjacent to saddle
gingival approaching i bar clasp

Question 19

list some examples of indirect retainers?

Answer 19

major connector
minor connectors
rests
saddles
denture base

Question 20

are RPIs usually utilised in the maxillary or radicular arch?

Answer 20

mandibular