Bridgework 1 Flashcards
Reasons for treating tooth loss
aesthetics
function
speech
maintenance of dental health
tooth replacement options
denture
bridgework
implants
What is a bridge
a prosthesis which replaces a missing tooth or teeth and is attached to one or more natural teeth (or implants)
2 main types of bridgework
Adhesive - held on with wings
Conventional - held on with crowns
most common type of bridgework
adhesive
indicaitons for bridgework (general)
function and stability
appearance
speech
psychological reasons
systemic disease e.g epileptics
OH co-operative patient
indications for bridgework (local)
big teeth
heavily restored (if conventional)
favourable abutment angulations
favourable occlusion (no too heavy contacts or fractures)
contraindications for bridgework (general)
uncooperative patient
medical history contra-indications
poor oh
high caries rate
periodontal disease
large pulps (conventional bridge - nb young pts as likely to cause non-vitality)
contraindicaitons for bridgework (local)
- high possibliity of further tooth loss within arch
- prognosis of abutment poor
- length of span too great
- ridge form and tissue loss
- tilting and rotation of teeth
- degree of restoration
- periapical status (active endo/perio disease)
- periodontal status (active or advanced)
Define abutment
a tooth which serves as an attachement for a bridge
define pontic
the artificial tooth which is suspended from the abutment teeth/tooth
define retainers
the extracoronal or intracoronal restorations that are connected to the pontic and cemented to the prepared abutment teeth e.g. like metal wing (adhesive) or crown (conventional)
define connectors
component which connects the pontic to the retainers/retainer
define edentulous span
space between natural teeth that is to be filled by a bridge or rpd
define saddle
area of edentulous ridge over which the pontic will lie
define pier
an abutment tooth which stands between and is supporting two pontics, each pontic being attached to a further abutment tooth
define unit
either a retainer or a pontic e.g. a bridge with two retainers and one pontic = 3 unit bridge
describe a fixed-fixed bridge
a retainer at each end with a pontic in the middle joined by rigid connectors (can be adhesive or conventional)
describe a cantilever bridge
a retainer (or retainers) at one side of the pontic only (can be adhesive or conventional)
Other names for resin retained bridgework
- adhesive bridgework
- minimal preparation bridgework
- maryland bridge
- resin bonded fixed partial denture
what are adhesive cantilever bridges made from
- all ceramic
- CoCr wing
advantages of RBBs
- minimal preparation (just an impression)
- no anaesthetic required
- less costly (porcelain + metal)
- less surgery time
- can be used as a provisional restoration e.g. hypodontia until old enough for implants
- if fails, usually less destructive than alternatives
disadvantages of RBBs
- rigourous clinical technique
- metal shine through
- chipping porcelain
- can debond
- occlusal interferences (less of a problem in static - dall concept)
- no trial period possible
indications for RBBs
- young teeth
- good enamel quality
- large abutment tooth surface area
- minimal occlusal load
- good for single tooth replacement
- simplify partial denture design
contraindications for rbbs
- insufficient or poor quality enamel
- long spans
- excess soft or hard tissue loss
- heavy occlusal force e.g. bruxist
- poorly aligned, tilted or spaced teeth
- contact sports (make sure mouth guards)
How would you treatment plan for rbbs
- history - establish habits e.g bruxism
- clinical exam - dynamic occlusal relationships, perio, radiological
- study models - mounted on semi-adjustable articulator with facebow registration, consider diagnostic wax-ups
how do you decide if bridgework is appropriate
- other options?
- make sure they know what a bridge is
- look at abutment teeth, occlusion, aesthetics including soft tissue contour
- can patient maintain complex work? OHI
why should you look at occlusion for bridgework
- consider opposing dentition - contact points, over-eruption of opposing teeth
- is there a parafunctional habit?
- dynamic occlusion - clinically, mounted study models, diagnositc wax ups
When would you use direct vs indirect RBB
Direct
- emergency situation
- if tooth needs extracted immediately
- if tooth lost traumatically
Indirect
- no preparation
- minimal prep
- heavy prep (undesirable e.g. dentine not as good a bond as enamel)
- get impressions, lab makes, second appt to put in
Describe options for pontic manufacture
- patients own tooth
- acrylic denture tooth
- polycarbonate crown
- cellulose matrix filled with composite
Example case of root fracture 11
- remove tooth
- cut off root and remove pulpal tissue
- etch contact points and composite over pulp chamber
- etch and bond
- composite to splint (buys time for long term solution)
what is needed for indirect RBB palatal/lingual coverage
- generous palatal/lingual coverage
- good quality enamel
- keep supra-gingival (0.5mm)
- care with coverage near incisal edge
what type of bridge work on anteriors
generally cantilever design
what type of bridge work on posteriors
generally fixed-fixed design
Why are cantilevers more successful anteriorally
Divergent guidance paths
- occlusal forces are directed in different ways, means when fixed-fixed there are 2 occlusal forces in 2 directions, more likely to come off
For RBBs what should we do about existing restorations in abutment teeth
- ideally sound enamel but not always possible
- composite
- ok
- however, consider replacing as better bond with newer composite/ roughen alternatively
- amalgam
- consider replacing as compromised bond to chemically cured composite cement
What prep might be required for RBBs
- 180 wrap around preparation
- rests
- rest seats on posteriors
- cingulum rests on anteriors
- +/- proximal grooves
- supra-gingival chamfer finish line
- ideally should remain in enamel
What prep might be required for anterior preparation
- cantilever design
- no preparation
- minimal prep
- occlusal contact reduction
- cingulum undercut removal only
- chamfer margin
- heavy prep
- 0.5mm palatal reduction (nb metal retainer wing should be 0.7mm thick)
- cingulum rest
- +/- proximal grooves
- chamfer margin (0.5mm supra-gingival)
what prep might be needed for posteiror teeth for rbbs
- no prep
- prep
- occlusal rests
- 180 wrap around (supra-gingival 0.5mm)
- +/- proximal grooves
- Fixed-fixed more likely as want to spread load down >1 abutment tooth on posterior but cantilever possible too
Temporisation of RBB
- consider RPD
- if prep remains in enamel- probably no need for temporary restoration
- prep into dentine + sensitivity = cover with layer of DBA
- fit bridge as quickly as possible (minimise over-eruption and tooth movement)
Describe the fit surface of retainer
- CoCr or NiCr alloy typically
- Sandblasted surface by lab
- micro-mechanical retention
- aluminium oxide-50microns
Describe how to cement an RBB
Treatment of Retainer
- try-in
- chairside micro-etching with 50 micron aluminium oxide particles (if not done by lab)
- clean retainer (ultrasonic bath if required, ethanol to ‘degreace’ if required)
- apply chemically (or dual cure) cure composite luting cement just prior to placement of restoration after tooth treatment
Treatment of tooth
- prophylaxis
- isolate with dental dam
- etch tooth
- wash and dry
- apply primer (A+B mixed) for 30 seconds
- air dry
- no need to cure (unlike for direct composite restorations)
Fit retainer
remove excess cement
oxygen inhibitor (oxyguard II) placed around cement margins for 3 minutes then wash off
what do we (GDH) use to cement RBBs
PANAVIA 21EX
What do you need to do post-cementation of RBB
- check occlusion
- no excessive occlusal forces on pontic
- demonstrate to patient how to clean around and underneath the bridge
- superfloss
- interdental brushes
Longevity of RBBs?
5 and 10 year survival rates about 80%
i.e. if they do fail its most likely to be in the first couple of years and if they make 5 years they will likely make 10 years
nb not finished
