L7 - definitive Flashcards
indirect restorations / fixed options
single units
multi units
implant supported crowns / bridges / splints
indirect restorations
partial dentures
full dentures
over dentures
implant supported or retained prosthetics
major options for material for crowns
gold / metal (semi-precious and non-precious)
porcelain / resin and hybrid ceramics
combinations of porcelain and metal
resin and metal
onlays vs amalgam and composites
amalgam and composite wear and stain and breakdown and must be replaced – finite life span and inlays use material with a LONGER life span
ceramic vs metal inlays
ceramic and resin inlays are BONDED = REINFORCE the tooth structure
metal inlays are cementd but mat be looked at as a WEDGE placed in the tooth – because of the divergent preps so create force
use of onlays
used to restore larger lesions with a material that has a long life span and to shoe or SUPPORT / PROTECT CUSPS
- amalgam onlays
- composite onlays (wear and stain and breakdown and have to be replaced - FINITE life span)
describe metal onlays - pros and cons
are cemented and are an excellent long term restorative option
pros
- RETAIN much of the natural tooth anatomy – can be used anywhere
- good for patient with parafunctional habits
cons
- not good against porcelain
- looked at as a aesthetic concers
good onnlay choice for parafunctional habit problems
metal
composite is what type
direct
what influences success of composite
size
location
isolation
occlusla forces
caries risk / hygeine (like amalgam could be less leakage?)
parafunctional habits
operator skills
pros of composite
tooth colored - bonded - seals and useful in small occlusal and interproximal lesions
cons of composite
micro -leakage, sensitivity, technique sensative
amalgam is good for and pros
restore defective in posterior teeth on the five surfaces of the tooth
missing cusps especially non functinal , core material
durable material long service life and works well in area where it is hard to visualize
inlay used for what size usually
like smaller lesiosn 1/3 width of tooth
ceramic and resin onlays are ___ to tooth? vs metal
BONDED
metal = cemented
pros and cons of cerami and resin onlays
pros
- reinforce the tooth structure
- aethstic
cons
- ceramics are subject to fracture if adequate THICKNESS is not maintained
- high skill level, technique sensative
- not for all situations and teeth - selective usage = success
esthetic of PFM depend on
reduction
- potential visiable metal margins
pros for use of PFM corwns
aesthetics compared to all metal
less aggressive prep than ceramic
multiple FINISH LINE OPTIONS
more places and conditions favor the use of PFM
bevels usually added when
situations where a shoulder is already present – and destruction by caries previous restoratins
facial of metal ceramic
metal restorations
shoulder use
all ceramic and margin of PFM crowns
radial shoulder
rounded shoulder – round ended tapered diamond ceramics need this
indications for chamfer
cast metal crowns and metal only portion of PFM crowns
heavy chamfer
ALL CERAMIC
cavo surface of chamfer
90 degrees but with havy – need a round end taperes
indication for knife edge margin
mandibular posterior teeth with very CONVEX axial surfaces
lingually tilted lower molars
knife edge permit
acute margin of metal
thin margin
suscetible to distortion
decision of PFM vs ceramic usually comes down to
finish line, location, and occlusion
prepare tooth and less than ___ there is a problem
less than 3 mm
which biotype for which type of crown
thick - pfm will work
thin – porcelain
canine guidance and crown material vs group fucntion
canine guidance – may want to think about PFM
grouo function – forces more distributed can do porcelain
clearance vs reduction
reduction – to only the tooth – to satisify the material using on that tooth
clearance – in relationship to the other arch
two unit bridge aka
cantilever
cantilever details
forces are put onto the pontic which is a potential problem
axis of rotation – is a lever
PFM connectors in bridge vs ceramic
PFM 4.5 square mm
ceramic 16 square mm
if you are going to bond a bridge in what do you need to consider?
do you have enough etchable tooth structure?
connector sizze is determined by
measuring the height from the gingival to incisal or occlusal as well as the width measured from buccal to lingual
guidelines for one pontic if zirconia in posterior and anterior
ceramics
9 square mm in posterior
7 square mm in anterior
guidelines for one pontic if lithium disilicate in posterior and anterior
16 square mm in posterior
12 square mm in anterior
case for marilyn bridge?
younger patients
one wing?
pre-requisite for veneers?
need enamel present – because needed to be bonded to this
veneers shade change dictates?
PORCELAIN THICKNESS
A3 to A0 requires?
0.6mm to 0.8mm reduction to achieve that change
main thing to think about when going to bond something
% of enamel left and locatino of that enamel
signs of overload
enamel crazing, abfraction lesions
signs of occlusal trauma
gingival recession and wear patterns
flexural risk assessment looks at
highest stress before rupture
rank materials from lowest MPa to highest
feldspathic
leucite-reinforced
lithium disilicate
glass-filled
alumina
zirconia
pascal =
pressure measurement
1 newton per square meter
MPa=
1 million Pa
bond strength to dentin =
19 MPa - 2756 psi
Emax bond strength
360-400 Mpa = 52k-58k psi
zirconia bond strenght
1170 MPa
lithium dislicate aka
emax
achilles heel of porcelain
shear and tensile stress assessment
stress - resist failure?
according to the load applies – so it is variable – force exerted on a material
like remove a bonded bracket from a tooth requires stress failure of the composite
implication of flaw in ceramic?
that is where stress will concentrate – propagation of cracks – yield to relieve stress and get DEFORMATIN
Deformation occuring?
in high stress area with no or little enamel
reduce the rotation radius?
put grooves in the axial walls
strength is derived from? implication of this?
derived from the ENAMEL
- so no enamel then high strength ceramic or a core material must be used
necessary to overcome deformity of the ceramic material
flexural strength
deformation / bend
tensile strength
resist pull apart
shear strength
how hard it is to cut – like paper and scissors
if using zironia what must you do at end?
POLISH
most ceramics are made how now?
milled or pressed
requirements for milled ceramics
need HIGH SHEAR STRENGTH OR THICKNESS of material AT THE EDGE / MARGIN of the restoration
sharp areas in ceramics?
concentrate stress – enemy
polish or glaze?
polish trumps glazing
implant supported removable in terms of soft ttissue?
soft tissue becomes LESS of a problem
what do you need in a patient?*
stable periodontal condition overall
free of carious lesions
STABLE OCCLUSION
what would i like in a patient?*
class I occlusion anteriorly and posteriorly
existing canine guidance
no occlusal interferences
major reasons for planing for a removable option
stabalize a denture
replace missing occlusal support
function
