Bridgework 1 Flashcards
tx options for missing tooth/teeth
- no tx/leave spapce
- replace tooth/teeth
- close space (orthodontics)
reasons for treating tooth loss (4)
- Aesthetics
- Function- masticatory
- Speech
- Maintenance of dental health
tooth replacement options
- denture
- bridgework
- implants
define bridge
“A prosthesis which replaces a missing tooth or teeth and is attached to one or more natural teeth (or implants)”
- Compared with a RPD which replaces soft tissue and bone(bridges do not replace soft tissue usually - limited)
2 types of bridgework
adhesive
- most common, held by wings on palatal surface
‘conventional’
- held by crowns
general indications for bridgework (6)
- Function and stability
- Appearance
- Speech
- Psychological reasons
- Systemic disease e.g. epileptics - no removable
- Co-operative patient – plaque control, no active disease, motivated
4 local indications for bridgework
- Big teeth
- Heavily restored teeth (for ‘conventional’ bridge)
- Favourable abutment angulations
- Favourable occlusion
6 general contraindications for bridgework
- Uncooperative patient
- Medical history contra-indications (e.g. allergies to metals)
- Poor oral hygiene
- High caries rate
- Periodontal disease
- Large pulps esp in primary teeth (conventional bridge
- Turkey teeth
8 local contraindications for bridge work
- High possibility of further tooth loss within arch
- Prognosis of abutment poor
- Length of span too great
-
Ridge form and tissue loss
- Denture tend to be better
- Gingival architecture concern with aesthetics not just tooth loss
- Tilting and rotation of teeth
- Degree of restoration (how much of tooth is left after preparation)
- Periapical status
- Periodontal status (bone loss) – active or advanced
abutment
a tooth which serves as an attachment for a bridge
pontic
the artificial tooth which is suspended from the abutement teeth/tooth
retainers
the extracoronal or intracoronal restorations that are connected to the pontic and cemented to the prepared abutment teeth
connectors
component which connects the pontic to the retainer(s)
edentulous span
space between natural teeth that is to be filled by a bridge
saddle
area of the edentuolous ridge over which the pontic will lie
pier
an abutment tooth which stands between and is supporting two pontic - each pontic being attached to a further abutment tooth
unit
either a retainer or a pontic
e.g. a bridge with two retainers and one pontic = 3 unit bridge
2 types of bridge design
fixed-fixed
cantilever
fixed-fixed bridge
This type of bridge has a retainer at each end with a pontic in the middle joined by rigid connectors.
- E.g. (Retainer)-(pontic)-(Retainer)
Can be:
- Adhesive/resin retained
- Conventional
cantilever
This type of bridge has a retainer (or retainers) at one side of the pontic only
- E.g. (Retainer)-(pontic)
Can be:
- Adhesive/resin retained
- Conventional
resin bonded bridgework (RBB) a.k.a
- Resin retained bridgework (RRB)
- Adhesive bridgework
- Minimal preparation bridgework
- Maryland bridge
- Resin bonded fixed partial denture (RBFPD)
2 options for adhesive cantilever bridges- material
all ceramic adhesive bridge
or
traditional adhesive bridge with metal (CoCr) wing
can be nickel chromium oness too
6 advantages of RBB
- Minimal or no preparation
- Occlusal contact can be high but tend to resolve in 10-14 days due to DAHL effect
- No anaesthetic needed
- Less costly
- Less surgery time
- Can be used as a provisional restoration
-
Hypodontia pt. – long term implant work, but wont want to provide till fully grown 18/19 girls and 20 boys
- Easy and quick to provide in teens and then can give implants when fully grown or when fails and then re-discuss options
-
Hypodontia pt. – long term implant work, but wont want to provide till fully grown 18/19 girls and 20 boys
- If fails - usually less destructive than alternatives
6 disadv of RBB
-
technique sensitive
- Need to be completely dry
- Metal shine-through
- See on 21 – poor cementation or design so metal seen at incisal edge
- Be careful not to overextend retainer
- See on 21 – poor cementation or design so metal seen at incisal edge
- Chipping pocelain - brittle
- Can debond
- High chance of it debonding again
- First bond will be best bond
- High chance of it debonding again
- Occlusal interferences – less of issue, DAHL concept
- No trial period possible
6 indications for RBB
-
Young teeth
- Less destructive
- Good enamel quality
- Large abutment tooth surface area (more bonding area)
- Minimal occlusal load
- Good for single tooth replacement
- Simplify partial denture design
6 contraindications for RBB
- Insufficient or poor quality enamel
- Long spans – break, # risk
- Excess soft or hard tissue loss
- Heavy occlusal force e.g. Bruxist
- Poorly aligned, tilted or spaced teeth
- Contact sports?
tx planning for RBB bridges
- History
- Establish habits e.g. Bruxism
- Examination
- Clinical
- Dynamic occlusal relationships
- Periodontal
- Radiological
- Caries, periapical pathology check
- Bone level
- Clinical
- Study models
- Mounted on semi-adjustable articulator with facebow registration
- Consider diagnostic wax-ups
occlusion considerations for bridgework planning
- Consider opposing dentition
- e.g. Contact points
- Over-eruption of opposing teeth
- Is there a parafunctional habit?
- Bruxism (clenching and/or grinding teeth)
- Look at dynamic occlusal relationships
- Clinically
- Mounted study models
- Consider diagnostic wax-ups
direct resin bonded bridgework used when?
- Very useful in emergency situation
- If tooth needs to be extracted immediately
- If tooth has been lost traumatically
indirect resin bonded bridgework
can be (3)
- No preparation
- Minimal preparation
- Heavy preparation (Undesirable)
- Dentine bone is poor compared to enamel
pontic manufacture for direct resin bonded bridgework
- Pontic manufacture
- Ideally use patient’s own tooth
- Alternatives:
- Acrylic ‘denture’ tooth
- Polycarbonate crown
- Cellulose matrix filled with composite
e.g. Root fracture tooth 11 – not restorable
where should margin sit on retainer prep?
Supra-gingival chamfer finish line ~0.5mm
indirect resin bonded bridgework - palatal/lingual coverage (metal)
- Need Greater surface area of enamel
- Need good quality enamel
- Keep supra-gingival
- Ideal 0.5mm
- Allow pt OH clean around gingiva – prevent caries
- Ideal 0.5mm
- Care with coverage near incisal edge
- Enamel translucent
- Grey shine through
- Enamel translucent
cantilever or fixed-fixed?
anterior
generally cantilever design
cantilever or fixed-fixed?
posterior
generally fixed-fixed
minimal or full prepartion first?
think long term
stick to simplest first before advancing to more destructive
Divergent guide paths in anterior mean more likely to use
cantilever designs
longitudinally axis of each tooth different, so occlusal forces directed down slightly differently causing a fixed-fixed restoration to get jutted about and more likely to debond
can abutment teeth have exisitng restorations?
ideally need sound enamel
- Composite
- OK?
- However consider composite replacement prior to preparation if old composite (better bond to new) or roughen with rose head bur
- Amalgam
- Compromised bond to chemically cured composite cement
- Consider replacing
preparation for RBB if needed
- 180º ‘wrap-around’ preparation on palatal/lingual surface
-
Rests – can help locate it on position and mechanical retention
- Rest seats (posterior teeth)
- Cingulum rest (anterior teeth)
- +/- Proximal grooves (mechanical retention – rare)
- Supra-gingival chamfer finish line ~0.5mm
- Ideally prep should remain in enamel
anterior RBB preparation options
- Cantilever design
- No preparation
- Minimal preparatio
- Heavier preparation
minimal prep for anterior cantilever
- Occlusal contact reduction – on abutment tooth
- Cingulum undercut removal only – path of insertion
- Chamfer margin (0.5mm supra-gingival)
heavier prep for anterior cantilever
- 0.5mm whole palatal surface reduction (NOTE – metal retainer wing should be 0.7mm thick), settle with time
- Cingulum rest
- +/- Proximal grooves
- Chamfer margin (0.5mm supra-gingival)
posterior RBB preparation options
- No preparation
- Preparation:
- Occlusal rests – 2mm deep
- 180º wrap-around with chamfer finish line (0.5mm supra-gingival) on palatal/lingual surface
- +/- Proximal grooves
- Can be cantilever or fixed-fixed design
- Increased occlusal force so tend to be better to spread the load over two abutment teeth to help inc longevity
temporisation for RBB options
cosider RPD or essix retainer with missing tooth incorporated
if prep remains in enamel - is there any need for a temporary restoration?
- May experience sensitivity – Duraphat toothpaste prescription
If prep into dentine and tooth becomes sensitive:
- Cover with thin layer of dentine bonding agent
Fit bridge as quickly as possible
- Minimise over-eruption and tooth movement (tilting into saddle space)
RBB prep remains in enamel temporisation needed
not necessarily
if experience sensitivity - duraphat toothpaste prescription
RBB extends into dentine temporisation needed
cover with thin layer of dentine bonding agent
temporisation length for RBB
short
fit bridge as quickly as possible - minimise over-eruption and tooth movement (tilting into saddle space)
fit surface of retainer
- Cobalt chrome or nickel-chromium alloy (typically)
-
Sandblasted surface
- Micro-mechanical retention
- Aluminium Oxide - 50 microns
cementation of RBB with
Panavia®21EX
a dual cured composite resin luting cement
treatment of retainer for cementation of RBB
Try-in
- Fit and aesthetics
- By hand or can ask lab to make a locating cleat on it – hook on incisal edge of retainer tooth
Chairside micro-etching with 50 micron aluminium oxide particles (sandblast)
- Should have already been done by technician
Clean retainer (if contaminated e.g. by unset composite resin used to try in bridge)
- Ultrasonic bath if required
- Use ethanol to ‘degrease’ if required
- Reduces surface tension
Apply chemically (or dual cure) cure composite luting cement just prior to placement of restoration after tooth treatment
treatment of tooth of RBB for cementation
- Prophylaxis
- Isolate with dental dam
- Etch tooth: 37% ortho-phosphoric acid (some preparations are 40%)
- Wash & dry
- Apply primer (A and B mixed together) for 30 seconds, about 5 layers
- Air dry for 2 seconds
- No need to cure (unlike for direct composite restorations), self cures
final stage of placement in cementation
- Fit retainer (coated with luting cement) to abutment tooth/teeth
- Remove excess cement
-
Oxygen inhibitor (Oxyguard II)placed around cement margins for 3 minutes
- Wash off
after cementation of RBB
- Check occlusion
- Confirm pontic does not have excessive occlusal forces applied, retaining wings less concern – will adjust with time and DAHL movements
- Demonstrate to patient how to clean around and underneath the bridge
-
Superfloss
- Thin and thick bits – feed the thin bit underneath the pontic and thread the thick bit through after whilst sweeping, show then pt demonstrate
- Interdental brushes
-
Superfloss
5 year survival of RBB
80.8%
most likely to fail within first 2 years
10 year survival of RBB
80.4%
most likley to fail within first 2 years
Fixed - moveable bridge
rigid connector on distal end of pontic, and a moveable conenctor mesially
- allow some vertical movement at the mesial abutment tooth
