Intro to Partials Flashcards
Kennedy class I
Bilateral distal extension
Kennedy class II
unilateral distal extension
Kennedy class III
unilateral tooth borne
Kennedy class IV
bilateral tooth born
- space must cross mid-line with no additional teeth missing for KC IV
- NEVER has modification space and ALWAYS crosses mid-line
all guide planes are…
minor connectors
T/F all minor connectors are guide planes
FALSE
- BUT all guide planes are minor connectors
path of insertion for removable abutments vs fixed
- identical (everywhere in arch)
- Guiding
- External
- Done by ‘surveying’
FIXED
- similar
- non-interfering
- internal
- done by eye (in the mouth)
guide planes determine
- path of insertion and withdrawl
path of insertion determines
height of contour
height of contour determines
location of undercuts
rests in function
stop GINGIVAL MOVEMENT
CLASPS in funciton
stop OCCLUSAL MOVEMENT
difference between cast partial and provisional partial
provisionals have no rests, no guide planes, no major connectors (cast partials do )
may or may not have wire claps
indications for removable partials
- distal extension
- long tooth borne span
- severe bone loss
- recent extraction
- high caries index
- poor crown/root ratio
- cost
all guide planes are?
minor connectors
we classify partials by?
the MOST POSTERIOR SPACE to be RESTORED by the partial
we modify partials by?
the number of REMAINING spaced to be RESTORED by the partial
rules for kennedy class IV
NEVER has modification spaces and ALWAYS crosses midline
kennedy classification DETERMINED BY
occlusal analysis
- why we MOUNT our cases
two types of partial denture movement
- vertical
2. rotational
tooth borne movement
vertical
distal extension movement
rotational
- down ward
- up ward
will a class III mod 1 rotate
likely not - but not a definitie answer if a hard yes or no choose no
what defines the axis of rotation?
the two most posterior rests
tooth borne class IV rotation implication?
if restoring a lot then absolutley will
back two define axis of rotation
tooth borne class III and IV with rotation are termed what?
MESIAL extensions
when are you more likely to have anterior rotation?
when pt. does not have cuspids/ canines and these need restoring as well
what does rotation depend upon?
the size of the anterior-posterior space
retention can be what two forms?
- direct
2. indirect
what keeps the denture down?
retention
direct retention prevents?
prevents VERTICAL MOVEMENT
Indirect retention prevents?
rotational movement
what does direct retention use to prevent vertical movement?
CLAPS
what does indirect retention use to prevent rotational movement?
RESTS
- think R and R (rests for rotation)
direct retainer aka
clasp
clasp assembly
- rest
- retainer (crosses height of contour and in undercut area)
- bracer (oppsoite and above height of contour)
absence of a bracer will cause what?
tooth movement
so the bracer is there to prevent tooth movement as clasp crosses the bulge
three types of rotation
- Antero-posterior (front to back)
- lateral (side to side)
- horizontal (twisting)
how many axes of rotation? what are they
three
1. A/P
- Lateral = midline of arch
- H = perpendicular to center of arch
A/P line =
line connecting last 2 rests and determines the A/P (front to back rotation)
where is the horizontal and lateral axes of rotaitno?
laterl = midline
Horizontal = perpendicular to center of arch
indirect retention opposes what type of rotation?
A/P rotation
what happens as denture base lifts away from tissue?
an OPPOSING REST SEATS against the tooth
describe indirect retention
during rotation the INDIRECT RETAINERS (rests) seat and prevent lifting of the distal extension
how to locate the indirect retainer
- locate the most posterior rests on each side
- connect them for form the axis of rotatin
- locate the midpoint of the axis
- locate the tooth PERPENDICULAR to the midpoint
- place a rest on that tooth OR MOVE LATERALLY to the nearest acceptable tooth (no incisors)
which teeth cannot be indirect retainers?
central incisors
- so move laterally to cuspids
how many indirect retainers do you uses? What does it depend on?
1 or 2 and depends on SYMMETRY
describe the relationship of effectiveness of the indirect retainer
it DECREASES as the distance from the axis of rotation DECREASES
where do we not place guide planes
on incisors and the MESIAL aspect canines
- because of esthetic reasons
symmetry is for what two things
rest and clasp
ante’s rule
If space is small enough for a bridge, use 1 clasp
if space is too large for a bridge, use 2 clasps
