Module 4 - RPD Flashcards
properties of RPD
- support
- stability
- retention
- reciprocation
- indirect retention
what do you add if you might lose a poor tooth and get a fulcrum line
indirect retainer
when do you need indirect retention
- kennedy class 1 and 2
- sometimes class 4
- kennedy class 3 ONLY IF you will lose the last tooth
denture base extends to __
- max: tuberosity
- mand: retromolar area. buccal flange to the vestibule. lingual flange to the depth permitted by mm
where does the external line start
2 mm lingual to the lingual surface of denture teeth
3 functions of tissue stops
- SUPPORT for distal extension base during metal framework try-in
- SPACE for packing acrylic under metal during processing
- facilitates RELINING in the future (if needed)
3 functions of rest seats
- prevent impingement of soft tissues
- maintain occlusal relationship (prevent denture from settling)
- directs occlusal load to abutment teeth (along their long axis)
dimensions for rest seat
1/2 BL distance
1/3-1/4 MD distance
how much restorative space do you need (from opposing tooth)
1.5 mm
dimensions of cingulum rest
MD: 2.5-3mm
BL: 1mm at margins, 1.5 at center
height: 1.5mm
*2mm away from gingiva
height of guide plane
2-3mm
- 2mm away from gingiva
- go past line angles
3 functions of guide planes
- guide to placement/removal of RPD
- reciprocation
- auxillary retention (provides friction, when you can’t use a clasp)
6 requirements of major connectors
- properly located
- avoids bony and soft tissue prominence
- not impinging on marginal gingiva
- rigid (to transmit stresses)
- not covering tissue
- not trapping food or providing retention
what happens if your major connector is not rigid enough
fracture, bc it cannot transfer stresses to the other arch during mastication
does the major connector contribute to retention
no
what components provide support
- rests
- major connector (in the maxilla)
where are support, stability, and retention found on a tooth
- support (occlusal third)
- stability (middle third)
- retention (below HOC)
what components provide stability
ALL COMPONENTS
- mainly minor connector
- lingual rest seats
- bracing arm of clasp
- teeth on other side of the arch
- major connector
- denture base
what components provide retention
- retentive arm of the clasp
- minor connectors
- denture base
if you only replace teeth on one side of the arch, you will have less ___
stability
acrylic dentures lack __ so they have less __
lack rest seats and bracing arm; so less support
distance between gingival margin and major connector
6 mm
where does the fulcrum line go
from most distal rest seats
what happens if you have K class 1/2, class 1 lever, and resorption
pressing down causes denture to go down and clasp comes up => extraction or fracture of tooth
when do you have class 1 levers
kennedy class 1/2, sometimes 4
patient with kennedy class 2 has tooth pain. what do you check for?
resorption => could be class 1 lever causing tooth pain => do a reline
effort arm direction
class 1 lever - down class 2 lever - up
function of indirect retainer
prevent displacement of dentures with distal extension away from tissues
class 2 lever is the solution to__
kennedy class 1/2 with class 1 lever (otherwise you have dislodgement of tooth, esp w resorption)
indirect retainer is the solution to__
kennedy class 1/2 with class 2 lever, if you eat sticky food the denture rotates about the fulcrum (effort arm is upward)
what do K class 1/2 require
- class 2 lever (RPI, RPA, or CC)
- indirect retainer
how does indirect retainer prevent rotation along fulcrum line
changes the location of fulcrum by increasing length of RESISTANCE ARM
