Bridgework Flashcards
what is the most common type of bridgework?
resin bonded (adhesive)
give 4 reasons for replacing missing dentition
-aesthetics
-function
-speech
-maintenance of dental health
what is a bridge?
a prosthesis which replaces a missing tooth/teeth and is attached to one or more natural teeth
list 6 general indications for bridgework
-function and stability
-appearance
-speech
-psychological reasons
-systemic diseases e.g. epilepsy
- co-operative pts
list 4 local indications for bridgework
-big teeth
-heavily restored teeth (conventional)
-favourable abutment angulations
-favourable occlusion
list 6 general contraindications for bridgework
-unco-operative pt
-medical history e.g. metal allergy
-poor OH
-high caries rate
-perio
-large pulps (conventional)
list 8 local contraindications for bridgework
-further tooth loss in arch likely
-poor prognosis of abutment
-length of span too great
-ridge form and tissue loss
-tilted/rotated abutment
-degree of rest. required
-periapical status
-periodontal status
define abutment
a tooth which serves s an attachment for a bridge
define Pontic
the artificial tooth which is suspended from the abutment teeth/tooth
define ‘retainer’
the extracoronal or intracoronal restorations that are connected to the Pontic and cemented to the prepared abutment teeth
define ‘connectors’
component which connects the Pontic to the retainers
define edentulous space
space between natural teeth that is to be filled by a prosthesis
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 is 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
what is a fixed-fixed bridge?
has a retainer at each end with a Pontic in the middle
joined by rigid connectors
what is a cantilever bridge?
has a retainer(s) at one side of the Pontic only
give 6 advantages of adhesive cantilever bridges
-minimal or no prep
-no anaesthetic needed
-less costly
-less surgery time
-can be used as a provisional for implant in kids
-less destructive in failure
what is the wing of an adhesive cantilever bridge made of?
can either be ceramic or CoCr (more common)
if a pt has a high occlusal concept point, how long will this take to resolve?
10-14 days
give 6 disadvantages of adhesive cantilever bridges
-requires good moisture control
-metal shine through
-chipping porcelain
-debonding (first bond is best)
-occlusal interferences
-no trial period possible
give 5 indications for adhesive cantilever bridgework
- young teeth
-good enamel quality
-large abutment tooth surface area
-minimal occlusal load
-good single tooth design
give 6 contraindications of for adhesive cantilever bridgework
-insufficient or poor enamel quality
-long spans; likely to flex on occlusion
-excess soft or hard tissue loss
-heavy occlusal force e.g. bruxism
-poorly aligned, tilted or spaced teeth
-contact sports (will get away w mouth guard)
Give 2 examples of when you would use direct resin bonded bridgework
-when the tooth needs to be extracted immediately
-if a tooth is lost traumatically
What is commonly used as the Pontic in direct resin bonded bridgework? Give 4 examples
Patients own tooth
Acrylic denture tooth
Polycarbonate crown
Cellulose matrix filled with composite
Why should the wing of an indirect resin bonded bridge be kept 0.5mm supragingival?
For cleaning
Why is a fixed-fixed indirect bonded bridge rarely used?
One wing usually rebinds and becomes a bacterial ingress
What type of patient is a fixed-fixed indirect bonded bridge useful for?
Post-Ortho patient
For indirect bonded bridgework, where in the mouth would fixed-fixed and cantilever design both be placed?
Anterior- cantilever
Posterior fixed-fixed
Why are cantilever indirect bridgework more successful anteriorly?
The longitudinal axis of anteriors are all different, meaning occlusal forces are directed down the teeth in different ways. The restoration would therefore get moved about in 2 different directions
Why should you consider replacing a composite restoration on an abutment tooth before placing bridgework?
You will get a better bind to new composite
Why should you consider replacing an amalgam restoration on an abutment tooth with composite before placing bridgework?
Amalgam will have a compromised bond to chemically cured composite cement
Why should the prep for bridgework ideally remain in the enamel?
For a better bond
How thick is a metal retainer wing for a cantilever bridge?
0.7mm
How deep should posterior occlusal rest seats be when placing a cantilever bridge?
2mm
How do you prep the fit surface of a CoCr bridgework retainer?
-sandblast for micro-mechanical retention
-aluminium oxide 50microns- creates indentations
What do you use to cement a bridge?
Chemically/dual cure composite outing cement e.g. Panavia21
What do you do after removing excess cement when placing a bridge?
Place an oxygen inhibitor (e.g. Oxyguard II) around the cement margins and then wash off
What do you use to etch prior to placing a bridge?
37% Ortho-phosphoric acid
What checks should you make after placing a bridge?
-check occlusion- there should be no excessive forces placed on Pontic
-check the pt can adequately clean around the Pontic
What is a hybrid bridge?
A bridge with a fixed retainer and an adhesive retainer
What types of patients are suitable for fixed-fixed bridges anteriorly?
-class 2 occlusion
-anterior open bite
Name 5 advantages of fixed-fixed bridgework
-robust design
-maximum retention and strength
-abutment teeth splinted together
-can be used in longer spans
-lab construction striaghtfirward
Name 4 disadvantages of fixed-fixed bridgework
-preparation must be parallel
-prep must be tapered 5-7o or crown can slide off
-common oath of insertion for abutments
-removal of tooth tissue means danger to pulp
Give 3 advantages if cantilever bridgework
-conservative design
-lab construction straight forward
-no need to ensure multiple tooth preps are parallel
Name 3 disadvantages of cantilever bridge work
-short span only
-rigid to avoid distortion (more prone to fracture)
-medial cantilever preferredas pt more likely to occlude on posterior teeth first
What are fixed moveable bridges used to overcome?
Abutment teeth not being parallel
Why are fixed moveable bridges named this?
It will flex when the pt occludes
Name 5 advantages of fixed moveable bridgework
- prep doesn’t require a common path of insertion, can be more conservative
-each prep design to be retentive independent if others
-more conservation of tooth tissue
-allows minor tooth movements
-may be cemented in 2 parts
Name 4 disadvantages of fixed moveable bridgework
-length of span is limited
-lab construction is more complicated
-possible difficulty in cleaning beneath moveable joint
-can’t construct provisional bridge
What is a spring cantilever bridge?
One Pontic attached to end of metal arm that runs across the palate to a rigid connector on the palatal side of a retainer
Name 2 advantages of spring cantilever bridgework
-useful if spacing present between upper incisors
Good when posterior tooth is a more suitable abutment
Name 5 disadvantages of spring cantilever bridgework
-can only be used to replace upper teeth
-difficult to clean beneath palatal connector
-may irritate he paltalmucosa
-difficult to control movement of Pontic due to springiness of metal atm/displacement of palatal soft tissues
-mucositis and inflammation usually seen direct,y behind the connector
What criteria must a tooth make to be suitable as an abutment?
-be able to withstand the forces previously directed to the missing teeth
-supporting tissues should be healthy and free of inflammation
-length of tooth coronal to alveolar crest compared to length of root embedded in bone (optimum 2:3) (minimum 1:1)
