bridgework Flashcards
(110 cards)
1
Q
tx options for missing tooth/teeth
A
no tx - leave space
replace
close space - ortho
2
Q
reasons for txing
A
aesthetics
fct
speech
maintenance of dental health
3
Q
replacement options
A
denture
bridgework
implants
4
Q
definition
A
a prosthesis which replaces a missing tooth/teeth and is attached to one or more natural teeth/implants
- fixed partial denture
- compared with a RPD which replaces ST and bone
adhesive or conventional
5
Q
general indications
A
fct and stability appearance speech psychological reasons systemic disease e.g. epileptics - small RPD aspiration risk co-operative pt
6
Q
local indications
A
big teeth heavily restored teeth - conventional destructive favourable abutment angulations favourable occlusions
7
Q
general contraindications
A
uncooperative pt MH contraindications poor OH high caries rate PDD large pulps (conventional)
8
Q
local contraindications
A
high possibility of further tooth loss within arch - look long term - dentures/implants
poor abutment prognosis
length of span too great
ridge form and tissue loss
- if teeth been missing for long time unlikely to get good aesthetics - bridges don’t replace ST, dentures better
tilting and rotation
degree of restoration (how much tooth is left after prep)
PA status
PD status (bone loss)
9
Q
abutment
A
a tooth which serves as an attachment for a bridge
10
Q
pontic
A
artificial tooth which is suspended from the abutments
11
Q
retainers
A
the EC or IC Rxs that are connected to the pontic and cemented to the prepared abutment tooth
12
Q
connectors
A
component which connects the pontic to the retainer(s)
13
Q
edentulous span
A
space between natural teeth that is to be filled with bridge/RPD
14
Q
saddle
A
area of the edentulous ridge over which the pontic will lie
15
Q
pier
A
abutment tooth which stands between and is supporting 2 pontics, each pontic being attached to a further abutment (rare)
16
Q
unit
A
retainer/pontic
17
Q
tooth preparations
A
conventional - not as common anymore
- retainer(s) = crown
- F-F, F-C, F-M
RR/adhesive
- retainer(s) = metal (NiCr or CoCr) - minimal/no prep
18
Q
bridge designs
A
fixed fixed - conventional or adhesive/RR cantilever - conventional or adhesive/RR fixed-moveable hybrid spring cantilever
19
Q
fixed fixed bridge
A
retainer at each end, pontic in middle, joined by rigid connectors
20
Q
advantages of fixed fixed bridges
A
robust max retention and strength abutments splinted together - perio mobile cases can use in longer spans lab construction straightforward
21
Q
disadvantages of fixed fixed bridges
A
prep difficult (parallel)
prep must be minimally tapered
common PofI for abutments
removal of tooth tissue (pulp)
22
Q
cantilever bridge
A
support for pontic at one end only
may be connected to one or more retainers
no retainer at other end of pontic
23
Q
advantages of cantilever bridges
A
conservative vs FF - only one tooth
lab construction straightforward
no need to ensure multiple tooth preps are parallel
24
Q
disadvantages of cantilever bridges
A
short span only (not as robust)
rigid to avoid distortion (fracture risk?)
mesial cantilever preferred
- abutment distal to pontic
25
fixed moveable bridge
has a rigid connector usually at distal end of pontic and a moveable connector mesially
- allows some vertical movement at the mesial abutment
potential solution when abutments aren't parallel
bridge in 2 parts
- slot and dovetail
- slot in (this bit flexes a little)
- have 2 PofIs
26
advantages of fixed moveable bridge
```
preps don't require a common PofI
each prep designed to be retentive independent of others
more conservative of tooth
allows minor tooth movement
may be cemented in 2 parts
```
27
disadvantages of fixed moveable bridge
length of span limited
lab construction complicated
possible difficulty cleaning beneath moveable joint-plaque trap
can't construct provisional
28
hybrid
1 retainer = conventional prep
| other retainer = min prep
29
spring cantilever
one pontic attached to the end of a metal arm that runs across the palate to a rigid connector on the palatal side of a retainer
v rare
30
advantages of a spring cantilever
useful if spacing between upper incisors
where adjacent teeth are unrestored
where a posterior tooth would provide a suitable abutment i.e. already has crown/large direct Rx
31
disadvantages of a spring cantilever
can only use to replace U incisors
difficult to clean beneath palatal connector
may irritate palatal mucosa
- candida infections
difficult to control movement of pontic, due to springiness of metal arm and displacement of palatal STs - v flexible
32
abutment evaluation
must be able to withstand forces prev directed to missing tooth/teeth (remaining tooth structure)
tissues healthy and free of inflammation i.e. PA and PDD
crown to root ratio
- length of tooth coronal to alv crest compared to length of root embedded in bone
- optimum 2:3, min 1:1
get radiographs
33
as a rule of thumb how long do bridges last if well maintained and looked after?
around 10 years
34
why do you need to have a plan for retrievability/back up plan?
will fail at some point
35
how should you examine the occlusion?
IO
| study casts - Facebow mounted on semi-adjustable articulator
36
what should you examine in regards to occlusion?
canine guidance/group fct - dynamic occ relationships
opposing tooth over-erupted?
will bridge interfere with current occlusion?
signs of parafct present?
- wear facets, attrition etc
37
designing and planning thoughts
min or conventional prep?
material? - metal stronger, ceramic aesthetic
abutment evaluation
cleansability - will fail if OH not easily performed, manual dexterity
appearance/aesthetics - confirm pts expectations are achievable
38
evaluating potential abutments
root configuration
angulation/rotation of abutment
PD health
surface area for bonding and quality of E
risk of pulpal damage
quality of endo - re-RCT?
remaining tooth structure present? - at least 2-3mm height
core - remove and rebuild? - but if need post and core risk of root fracture
39
details of bridge design
select abutments
- judge longevity of adjacent teeth
select retainer
- no/min/regular prep? RBBs
- complete crown? conventional
select pontic and connector
plan occlusion
- avoid having contact on just pontic. Need contact on just retainer or on pontic and retainer
prescribe material
40
pontic fct
restore appearance of missing tooth
stabilise occlusion
- prevent tilting and overeruption
improve masticatory function
41
3 considerations for pontic design
cleansability
appearance
strength
42
considerations for pontic design - cleansability
smooth, with highly polished or glazed surface
surface shouldn't harbour join of metal and porcelain (if metal ceramic design used)
embrasure space smooth and cleansable
43
considerations for pontic design - appearance
anteriorly - tooth like as possible
| posteriorly - may compromise
44
considerations for pontic design - strength
longer span = greater thickness required to withstand occlusal forces (because flex increases fracture risk)
45
surfaces of pontic
occlusal
approximal
buccal and lingual
ridge
46
surfaces of pontic - occlusal
resemble surface of tooth it replaces
narrower nearer cervical area to enable cleaning
should have sufficient occlusal contact
- esp if replacing for masticatory fct
47
surfaces of pontic - approximal
connector: strength
embrasure: space (floss)
48
wash through/hygienic/sanitary
makes no contact with ST - not supported by ridge
fct (increase occ area) rather than for appearance
consider in lower molar area
v cleansable - brush/saliva
slightly more prone to fracture due to flex - gold good material
49
dome/bullet/torpedo
just touches ridge
useful in lower incisor, premolar or upper molar areas
acceptable if occlusal 2/3 of buccal surface visible
poor aesthetics if gingival 1/3 of tooth visible
quite cleansable in lower 1/3
50
modified ridge lap
most commonly used
buccal surface looks as much like tooth as possible
lingual surface cut away (cleansable)
line contact with buccal of ridge
problems with food packing on lingual surface of ridge
51
total ridge lap/saddle
good aesthetics
greatest contact with ST
if designed carefully can be cleansed
less food packing than modified ridge lap - but if there is food packing, really hard to get out
careful not to displace ST or cause blanching of tissue
52
ovate
presses on ridge lap/saddle (2-3mm)
can be used to "mould and shape" gingivae
difficult to clean - increase risk of inflammation on saddle
often used with long term implant aim - emergence profile
may be a little uncomfortable - warn pt
53
materials that can be used
all metal
metal ceramic
all ceramic
ceromeric
54
materials that can be used - all metal
gold best - lower posteriors
| Ni/Co Cr?
55
what are the majority of bridges made in at present?
metal ceramic
56
materials that can be used - all ceramic
Zi e.g. Lava and Procera
| lithium disilicate e.g. Emax
57
materials that can be used - ceromeric
not as common now
combination of composite and porcelain material
BelleGlass, Vectris, TargisVectris
58
lava 3M espe
3-4 unit fixed bridge (max span) milled zirconium oxide frame with feldspathic porcelain overlying
withstand occ forces
good aesthetics
similar reduction to MCC
59
Zi
preps on casts scanned
katana Zi - multilayered Zi, ultra translucent multilayer Zi
milled
+/- feldspathic (layer) porcelain on top
60
implant retained bridges
large span bridges (implants can be abutments)
61
screw-retained implant bridges
ideal
| more retrievable and easy to dismantle
62
cement-retained implant bridges
if cant get them in perfect SL access
| much harder to dismantle
63
which bridge requires parallelism?
F-F conventional
requires 2 or more teeth to be prepared to provide a common PofI
no undercuts but to give retentive preps
64
paralleling by eye
direct vision, one eye closed
large mouth mirror posteriorly (hold at same angle)
use straight (right angle) probe like a lab surveyor but in the mouth
65
EO survey for paralleling
quick imp
pour model
use a lab surveyor, useful in long span multiple unit bridges
66
before starting preparation for conventional bridgework, what steps should be taken?
mounted study models
consider diagnostic wax up and custom imp tray
request lab to construct vacuum formed stent
- allows checking of reduction during tooth prep
- allows construction of provisional bridge (Protemp)
shade
lab made stent or make pre-op putty impression for provisional bridge
67
prep conventional bridgework
occlusal or incisal reduction
separation of teeth
aim for parallelism of tapered surface of each prep
confirm parallelism
consider retentive features if short clinical crown height or over tapered - slots/grooves - rare as adhesives good
construct provisional bridge before imp - as then means you can get them back for imp if you run out of time
make imp and occlusal reg
temporarily cement provisional bridge
demonstrate cleaning with superfloss
write/draw prescription for technician
68
definitive cementation - conventional metal and metal ceramic (fitting surface metal)
AquaCem (GIC) - avoid biting for 24hrs on it
RelyXLuting (RMGIC)
69
definitive cementation - adhesive bridge
Panavia21
anaerobic dual cure resin cement with 10-MDP
- good bond between tooth and metal
70
definitive cementation - all ceramic
```
NEXUS kit (dual cure resin cement)
can't shine a light cure reliably
```
71
distal cantilevers - why are they avoided?
tend to chew posteriorly, contact on pontic first
concern that occlusal forces on pontic will produce leverage forces on abutment causing tilting
mesial relieves the pontic (contact on retainer first)
72
when might a distal cantilever be indicated?
e.g. in 4-4s to give a SDA
| from premolar abutment if unopposed or opposed by a denture
73
5 and 10 year longevity rates of RBBs
80.8%
80.4%
if it is going to fail it tends to fail in first 2yrs
74
longevity of F-F MC
90%
75
longevity of F-F C
88%
76
success of implant root
97%
77
longevity of implant retained bridge
95. 2%
| 86. 7%
78
longevity of conventional cantilever
91. 4%
| 80. 3%
79
removing adhesive bridgework
SafeRelax
| Anthrogyr
80
adhesive cantilever materials
all ceramic - more recent, not much evidence yet
| ceramic with metal (NiCr/CoCr) wing - traditional
81
advantages of adhesive bridgework
min/no prep
no anaesthetic needed
less £
less surgery time
can be used as provisional e.g. long-term aim of implant (children)
if fails usually less destructive than alternatives
82
disadvantages of adhesive bridgework
rigorous clinical technique
metal shine through esp incisal edge
can debond (v little mechanical retention, relying on chemical)
- high chance of debonding again
- quality of E decreases
occlusal interferences - high failure in bruxists
no trial period possible
83
indications for adhesive bridgework
```
young teeth (less destructive)
good E quality
large abutment tooth surface area
minimal occlusal load (anterior teeth)
single tooth replacement
simplify RPD design
```
84
contraindications for adhesive bridgework
```
insufficient or poor quality E e.g. amelogenesis imperfecta
long spans
- more pontics = more occlusal load
excess hard or soft tissue loss
- loss of ID papillae - black triangles
heavy occlusal force e.g. bruxism
- can do but need to give splint to protect bridge
poorly aligned, tilted or spaced teeth
contact sports?
```
85
assessing the occlusion
```
consider opposing dentition
- contact points
- over-eruption of opposing teeth/tilting
is there a parafct habit? - wear facets, linea alba
look at dynamic occlusal relationships
- clinically
- mounted study models with facebow
- consider diagnostic wax ups
```
86
types of adhesive bridge
direct
| indirect
87
direct adhesive bridges
rare
v useful in emergency situation
immediate extraction or traumatically lost
88
construction of a direct adhesive bridge
pontic manufacture - ideally use pts own tooth
alternatives - acrylic 'denture' tooth, polycarbonate crown, cellulose matrix filled with composite
extract, drill root, remove pulp, cover orifice with composite, etch and bond IP areas
89
levels of prep for an indirect adhesive bridge
no
min
heavier
90
why is it ideal to bond to enamel?
dentine doesn't bond as well to resin cement
91
requirements for indirect adhesive bridge
need generous palatal/lingual coverage
- greater SE of E covered - greater bond
keep supra gingival - ideal 0.5mm
care with coverage near incisal edge - enamel translucent
ideally prep should remain in enamel 0.5mm
92
providing bridge after extraction
don't provide until 3m maxilla and 6m mandible after ext to allow healing
- related to blood supply - U cancellous bone vs L cortical bone
93
what type of adhesive bridge is usually used anteriorly?
cantilever
94
what type of adhesive bridge is usually used posteriorly?
F-F
| increased occlusal load
95
divergent guidance paths
why cantilevers are more successful anteriorly?
- want only single direction of occlusal force
- otherwise get shear forces - one side may debond
96
restorations in abutment teeth for adhesive bridgework
ideally need sound E
composite ok
- consider replacement prior to prep (esp if old)
amalgam
- compromised bond to chemically cured composite cement
- consider replacement (w composite)
97
anterior adhesive bridge - min prep
occlusal contact reduction
cingulum undercut removal only
chamfer margin 0.5mm supragingival
98
anterior adhesive bridge - heavier prep
0.5mm palatal reduction - retainer wing should be 0.7mm thick - get occ adjustment in 2 weeks
cingulum rest (mechanical retention)
+/- proximal grooves
chamfer margin 0.5mm supragingival
99
posterior adhesive bridgework prep options
no prep
| prep
100
posterior adhesive bridgework prep
occlusal rests (mechanical retention)
180 degree wrap around with chamfer finish 0.5mm supra gingival
+/- proximal grooves
can be cantilever or FF
101
what is modern adhesive bridgework made from?
NiCr alloy
102
sandblasting surface of adhesive bridgework
micro mechanical retention - from wing not tooth (cement flows into the dents)
aluminium oxide - 50 microns
103
temporisation for adhesive bridgework
consider RPD
if prep remains in E - do you need temp?
if prep into D and tooth becomes sensitive cover with a layer of DBA
fit bridge as quickly as possible
- minimise over-eruption and tooth movement
104
what do you use to cement adhesive bridgework?
panavia 21 ex
105
what does Panavia 21 ex contain to allow tooth tissue to stick to metal better?
10 MDP
106
adhesive bridgework - tx of retainer
try in - fit and aesthetics
chair side micro etching with 50 micron Al2O3 particles - sandblast (should already have been done by technician)
clean retainer
- US bath if required
- ethanol to 'degrease' if required (reduce surface tension)
apply chemical/dual cure composite luting cement just prior to placement of Rx after tooth tx
107
adhesive bridgework - tx of tooth
```
prophylaxis
isolate with dental dam
etch (37% orthophosphoric acid)
wash and dry
primer 30s (don't cure)
air dry 2s
```
108
cementing the adhesive bridgework
fit adhesive bridge retainer (coated with luting cement) to abutment
remove excess cement
- can light cure after this to speed setting
oxygen inhibitor (oxyguard 2) placed around cement margins for 3mins, then wash off
2mins of finger pressure - hold while setting to ensure correct position
109
locating clique e.g. duralay
hooks over incisal edge to ensure cement bridge in correct location
can twist/drill off post-cementation
110
post-cementation of adhesive bridgework
check occlusion
- confirm pontic doesn't have excessive occlusal forces applied
demonstrate to pt how to clean around and underneath bridge with superfloss
