Bridgework Flashcards
What are the treatment options for missing teeth?
- no treatment
- replace tooth
- bridge
- implant
- denture
- close space
- orthodontics
What are the 4 reasons for treating tooth loss?
- aesthetics
- function
- speech
- contact between tongue and tooth surface to make noise is restored
- maintenance of dental health
- prevention of tilting and over-eruption
What is the definition of a bridge?
a prosthesis which replaces a missing tooth or teeth and is attached to one or more natural teeth or implants
What do removable partial dentures replace that bridges do not?
soft tissues and bone
- bridges can have some soft tissue prosthesis included but it is very limited
What are the two main types of bridgework?
- adhesive
- conventional
What are general indications for bridgework?
- function and stability
- appearance
- speech
- psychological reasons
- some patients are opposed to RPDs
- systemic diseases
- epileptics
- small RPDs can be inhaled or broken during seizures
- epileptics
- co-operative patient
- must be compliant
- good oral hygiene
What are local indications for bridgework?
- big teeth
- increased retention
- heavily restored teeth
- conventional bridgework
- favourable abutment angulations
- favourable occlusion
- heavy occlusal contacts increase chance of fracture or debonding
What are general contraindications for bridgework?
- uncooperative patient
- medical history
- allergies to materials
- poor oral hygiene
- high caries risk
- periodontal disease
- large pulp
- conventional bridgework
- larger pulps in younger teeth
- can become non-vital during prep
- RCT would be required
What are local contraindications for bridgework?
- high possibility of further tooth loss within arch
- poor prognosis of abutment teeth
- length of span too great
- bridges can only replace 2-3 teeth
- ideally as few as possible to reduce flex
- ridge form and tissue loss
- if lots lost a denture may be more appropriate
- aesthetic of gingival architecture
- tilting and rotation of teeth
- difficult to attach bridgework
- occlusion on bridge may be unfavourable
- degree of restoration
- must have some remaining tooth tissue
- periapical status
- no active endodontic or pulpal disease
- must be treated first to be considered for an abutment
- periodontal status
- no active or advanced periodontal disease
- teeth likely mobile
What type of ridge form makes bridgework challenging?
flat ridge
- restoration of stippled gingival contour challenging
- advanced techniques required to re-shape
What is the definition of an abutment tooth?
a tooth which serves as an attachment for a bridge
What is the definition of a pontic?
an artificial tooth which is suspended from the abutment tooth/teeth
What is the definition of a bridge retainer?
the extracoronal or intracoronal restorations that are connected to the pontic and cemented to the prepared abutment teeth
What is the definition of a bridge connector?
the component which connects the pontic to the retainer/retainers
What is the definition of a bridge pier?
an abutment tooth which stands between and is supporting two pontics with each pontic being attached to a further abutment tooth
What is the definition of a bridge unit?
either a retainer or a pontic
In what situations are piers used in bridgework?
large bridgework designs
What are the 5 different type of bridge designs?
- fixed-fixed bridge
- conventional
- adhesive
- cantilever bridge
- conventional
- adhesive
- fixed-moveable bridge
- hybrid bridge
- fixed retainer and adhesive retainer
- spring cantilever bridge
What is a fixed-fixed bridge?
a bridge with a retainer at each end and a pontic in the middle joined by rigid connectors
- can be adhesive or conventional
In what scenarios are large span fixed-fixed bridges appropriate?
- class 2 occlusion
- little occlusal contact
- less flex experienced
What are other names given to adhesive bridgework?
- resin retained bridgework (RRB)
- resin bonded bridgework (RBB)
- minimal preparation bridgework
- maryland bridge
- resin bonded fixed partial denture (RBFPD)
What are the most common materials for adhesive cantilever bridges?
- porcelain pontic and metal retainer
- CoCr or NiCr retainer
What are the advantages of adhesive bridges?
- minimal to no preparation
- no anaesthetic needed
- less costly
- less surgery time
- can be used as a provisional
- patient with hypodontia too young for implants
- less destructive on failure
How are high occlusal contacts resolved when bridgework is placed?
Dahl Concept
- high contacts resolve over 10-14 days
- relative axial tooth movement
What are the disadvantages of adhesive bridgework?
- rigorous clinical technique
- moisture control vital for composite cement
- contamination with saliva can reduce longevity
- metal shine through
- poor design
- inadequate cementation
- not kept away from thin incisal edges
- can debond
- high chance of repeat debonding
- first bond is best bond
- pontic most likely to chip
- occlusal interferences
- occlusion tends to adjust
- dynamic interferences cause problems
- mandible hits maxillary bridgework and lateral forces cause deboning
- no trial period
- cannot see aesthetics
- cementation required
What are the indications for adhesive bridgework?
- young teeth
- less destructive
- good enamel quality
- required for a good bond
- large abutment tooth surface area
- minimal occlusal load
- single tooth replacement
- simplify partial denture design
What are the contraindications for adhesive bridgework?
- insufficient or poor quality enamel
- long spans
- excess soft or hard tissue loss
- flat gingival saddle makes recreation of gingival architecture with papilla challenging
- heavy occlusal forces
- e.g. bruxists
- poorly aligned, tilted or spaced teeth
- path of insertion and aesthetics challenging
- contact sports
- increased trauma to area
- mouth guard required to protect bridgework
What must be identified in a history for a potential bridgework patient?
- habits
- bruxism
What must be included in an examination for a potential bridgework patient?
- dynamic occlusal relationships
- periodontal status
- radiological examination
- periapical pathology
- bone levels
What are study models used for in bridgework treatment planning?
- face bow registration
- semi-adjustable articulator
- diagnostic wax ups
- aesthetics
- potential interference
What factors are considered in the decision making process for bridgework?
- abutment teeth
- prognosis
- occlusion
- aesthetics
- work backwards from desired final aesthetic result
- other treatment options
- implants
- dentures
- patient preference
- cautious of insistent patients
- manage expectations and explain pros and cons
- patient compliance
- bridgework requires maintenance
- patient must be motivated
How can occlusion impact on decision making surrounding bridgework?
- opposing dentition
- heavy contact points
- overeruption
- parafunctional habit
- bruxism
- clenching/grinding
- bruxism
- dynamic occlusal relationships
- clinically
- mounted study models
- consider diagnostic wax ups
What is direct resin retained bridgework?
a bridge made chairside while the patient is present
When is direct resin retained bridgework used?
- emergency situation
- patient doesn’t want to be left with an edentulous space
- teeth need extracted immediately
- tooth has been lost traumatically
What is indirect resin retained bridgework?
bridgework made in laboratory from impressions taken then prosthesis cemented in at a second appointment
What are the three different preparation types for indirect resin retained bridgework?
- no preparation
- resin bonded
- minimal preparation
- resin bonded
- heavy preparation
- conventional
- undesirable
- exposes dentine which has a poorer bond strength than enamel
What is used as a pontic for direct resin retained bridgework?
- ideally patients own tooth
- if tooth lost from trauma
- acrylic denture tooth
- polycarbonate crown
- cellulose matrix filled with composite
What is the process for using a patient’s own tooth for a direct resin retained bridge?
- tooth deemed unrestorable
- root cut off crown and pulpal tissues removed
- barbed broaches used
- pulp chamber filled with composite
- contact points on pontic tooth and adjacent teeth etched, primed and bonded
- composite used to attach pontic tooth
What are the advantages and disadvantages of direct resin retained bridges?
- advantages
- tooth is in situ
- treatment options can be discussed
- disadvantages
- aesthetics poor
What palatal/lingual coverage is required for indirect adhesive bridgework?
- generous palatal/lingual coverage
- greater surface area = greater bond
- good quality enamel
- supra-gingival coverage
- ideally by 0.5mm
- allows for cleans ability of gingival margin
- reduced risk of periodontal disease
- reduced coverage at incisal edge
- enamel is more translucent
- avoids grey shine through
How far away from the gingival margin should resin bonded bridge retainers be kept?
0.5mm
Where can fixed-fixed resin bonded bridges be used?
- patients with previous orthodontic treatment
- hold teeth in place
- lower teeth
Where are fixed-fixed resin bonded bridges rarely used and why?
- anteriorly
- divergent guidance applied to teeth
- longitudinal axis of the teeth vary along the arch
- one of the retainers debonds
- space allows for bacterial ingress
- caries develop
What type of bridge design is most common anteriorly?
cantilever
What type of bridge is most common posteriorly?
fixed-fixed
- debonding is more obvious and can be dealt with
- spreads the greater occlusal forces over two teeth
- increases longevity of bridge
How must restorations in abutment teeth be considered before bridgework can be considered?
- ideally sound enamel is present
- usually restorations will be present
- composite restorations
- are acceptable
- consider replacement prior to preparation
- better bond to newer composite
- can roughen existing composite with a Rosemead bur to increase retention
- amalgam restorations
- compromised bond to chemically fired composite cement
- consider replacing with composite
Describe the possible aspects of preparation of an abutment tooth for a resin bonded bridge
- 180 degree wrap-around preparation
- palatal/lingual surface
- rests
- rest seats for posterior teeth
- cingulum rests for anterior teeth
- increase mechanical retention
- less common due to modern resin cements
- useful for location during cementation
- proximal grooves
- increase mechanical retention
- less common due to modern resin cements
- vertical cuts towards interproximal surfaces
- rarely used
- supra-gingival chamfer finish line
- approximately 0.5mm above gingival margin
- chamfer bur
- enamel only prep
Describe minimal preparation of an anterior tooth for a resin bonded bridge
- occlusal contact reduction
- where heavy occlusal contact is suspected
- cingulum undercut removal
- aids path of insertion
- chamfer margin
- 0.5mm supra-gingival
Describe heave prep of an anterior tooth for a resin bonded bridge
- 0.5mm palatal reduction
- retainer will be 0.7mm thick
- adjusts due to Dahl Concept
- retainer will be 0.7mm thick
- cingulum rest
- possibly proximal grooves
- chamfer margin
- 0.5mm supra-gingival
Describe preparation of a posterior tooth for a resin bonded bridge
- occlusal rest seats
- 2mm depth
- incorporated into surface anatomy of teeth
- 180 degree wrap-around
- palatal/lingual surface
- chamfer finish line
- 0.5mm supra gingival
- proximal grooves
- middle of palatal/lingual aspect
- not usually required
What are the options for temporisation during the laboratory phase for an indirect resin bonded bridge?
- no temporisation
- if prep remains only in enamel
- recommend sensitive toothpaste
- RPD
- some can tolerate for short period of time
- dentine bonding agent
- if prep enters dentine
- can reduce sensitivity
- Essix retainer
- clear retainer with missing tooth incorporated
Why should bridges be placed as quickly as possible?
- minimised over-eruption and tooth movement
How are metal wing retainers sand-blasted and why is this carried out?
- aluminium oxide particles fired at CoCr or NiCr
- 50 micron diameter
- creates small indentations on fitting surface
- resin cements flows in and sets
- increased mechanical retention
Describe the cementation process of resin bonded bridgework
- try in
- secure with small amount of composite
- assessment of aesthetics and fit
- locating cleat over incisal edge
- sandblasting
- should have been performed by lab
- clean retainer
- ultrasonic bath if needed
- ethanol to degrease
- may require further sandblasting
- apply chemically or dual cure composite luting cement
- ideally dual cure (Panavia 21)
- abutment tooth
- prophylaxis
- isolation with dental dam
- etch with 37% phosphoric acid
- wash and dry
- apply primer for 30 seconds
- air dry for 2 seconds
- fit bridge retainer coated with luting cement to abutment tooth
- remove excess cement
- oxygen inhibitor (oxyguard II) placed around margins for 3 minutes
- wash off
How many layers of Panavia 21 primer should be applied to an abutment tooth before cementation?
5 layers over 30 seconds
Describe what must be performed post-cementation
- check occlusion
- static and dynamic
- confirm pontic does not have occlusal forces applied
- heavy contacts on pontic should be adjusted
- demonstrate cleaning to patient
- underneath and around bridgework
- feed thin part of superfloss under pontic and pull thick part under
- can also use interdental brushes
What are the advantages of fixed-fixed bridge designs?
- robust
- crowns as retainers
- maximum retention and strength
- not reliant on adhesive retention
- mechanical retention and bond present
- abutment teeth are splinted together
- long standing but stable perio cases
- increases stability
- longer spans possible
- laboratory construction straightforward
What are the disadvantages of fixed-fixed bridge designs?
- preparation difficult
- parallel preparations difficult
- preparation must be minimally tapered
- difficult when trying to make parallel
- aiming for 5-7 degree taper
- more than 10 degrees eliminates single path of insertion
- common path of insertion for abutments
- increases retention
- removal of tissue
- danger to pulp
- particularly heavy prep for all ceramic
- tooth can become non-vital
What is the ideal taper for an abutment preparation for a fixed-fixed bridge?
5-7 degrees
What are the advantages of conventional cantilever bridges?
- conservative design
- only one crown prep required
- laboratory construction straightforward
- do not need to ensure parallel guide planes
What are the disadvantages of conventional cantilever bridges?
- short span only
- less successful in longer spans
- rigid to avoid distortion
- rigidity increases fracture risk
- common in porcelain when flex isn’t possible
- mesial cantilever preferred
- most posterior teeth occlude first
Why is a mesial cantilever preferred?
- most posterior teeth occlude first
- distal cantilever likely to have a heavy contact
- see saw effect with restoration coming off
When can distal cantilevers be considered?
when a patient is missing all posterior teeth, with only 1-4 present. distal cantilever can be placed on 4s to replace 5s, patient must be aware of risks
What is a fixed moveable bridge?
- bridge with two components
- crown retainer
- crown retainer and pontic
- retainer is separate to retainer and pontic
- two paths of insertion
- components slot together
- some element of flex
When could a fixed moveable bridge be used?
- when abutment teeth are not parallel
- alternative to heavy preparations
What are the advantaged of a conventional fixed moveable bridge?
- preparations don’t require a common path of insertion
- each preparation is retentive independent of the others
- more conservative of tooth tissue
- don’t need to remove excess to make parallel
- allows minor tooth movement
- may be cemented in two parts
What are the disadvantages of a conventional fixed-moveable bridge?
- length of span limited
- can only replace one tooth
- due to increased flex
- laboratory construction more complicated
- may need a longer lab time
- possible difficulty in cleaning
- beneath moveable joint
- small gap where plaque can accumulate
- patient must have excellent oral hygiene
- increased risk of caries and perio
- cannot construct provisional bridge
What is a hybrid bridge?
bridge with one conventional retainer and one adhesive retainer
When are hybrid bridges used?
- rarely used
- conventional cantilever is sufficient
- adhesive retainer likely to debond
- conventional retainer is robust
- unlikely to detect debonding and micro leakage
What is a spring cantilever bridge?
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
When are spring cantilever bridges used?
- not re-prescribed
- resin bonded bridge from adjacent tooth instead
- aim to be more conservative to anterior tooth tissue
- useful if spacing present between upper incisors, adjacent teeth are unrestored and a posterior tooth would be a suitable abutment
- only for upper incisors
- difficult to clean beneath palatal connector and may irritate palatal mucosa
- have to flex arm to clean underlying mucosa
- increased risk of candidal infections
- difficult to control movement of pontic due to springiness of metal arm and displacement of palatal soft tissues
- can move a lot
- pinging arm can become habitual
What is involved in the evaluation of an abutment tooth?
- must be able to withstand forces previously directed to the missing tooth/teeth
- supporting tissues should he healthy and free of inflammation
- no periapical or periodontal disease
- crown to root ration
- length of tooth coronal to alveolar crest compared to length of root embedded in bone
- optimal ration is 2:3
- minimum ratio is 1:1
- length of tooth coronal to alveolar crest compared to length of root embedded in bone
- angulation/rotation of abutment
- root configuration
- multiple, larger roots can withstand greater forces
- surface area and quality of enamel
- enamel provides a superior bond to dentine
- enamel defects reduce bonding potential
- increased surface area increases bond
- risk of pulpal damage
- especially must consider for conventional bridgework
- quality of endodontics
- option to re-RCT
- must have confidence in the RCT before placing bridgework
- reduce risk of periapical infection to prevent having to remove bridge
- core
- removal of core to re-build
- composite core most common
- can consider crown lengthening surgery
What occlusal information is required before determining whether bridgework is appropriate?
- guidance present
- canine guidance
- group function
- incisal classification
- reduced interocclusal space
- over erupted opposing teeth
- parafunctional habits
- bruxism
- wear facets
- attrition
- bruxism
What are the 5 sections that must be considered when designing and planning bridges?
- type of preparation
- aim to conserve as much tooth tissue as possible
- where robust bridgework is required, conventional may be necessary
- abutment evaluation
- pulpal status
- periodontal status
- previous RCT
- cleansibility
- patient’s oral hygiene - aesthetics
- consider limitations of bridgework
- lower high patient expectations - material
- what is most suitable for the patient
What are the 5 details of bridge design that must be included in the lab prescription?
- selected abutment teeth
- must consider longevity of abutments
- selected retainer
- no prep
- minimal prep
- regular prep
- conventional prep
- selected pontic and connector
- sanitary/wash-through
- dome/bullet/torpedo
- modified ridge lap
- total ridge lap
- ovate
- planned occlusion
- prescribed material
What are the 5 different types of pontic?
- sanitary/wash-through
- dome/bullet/torpedo
- modified ridge lap
- total ridge lap
- ovate
What are the considerations when choosing a pontic design?
- cleansibility
- smooth, well polished or glazed surface
- plaque should not easily adhere
- no surface joins of materials
- occlusal forces can cause shearing
- smooth and cleansable embrasure space
- plaque and food should not be trapped
- easy to clean and brush around
- smooth, well polished or glazed surface
- appearance
- anterior should look as much like a tooth as possible
- aesthetic zone
- aesthetics of posterior can be compromised
- functional zone
- anterior should look as much like a tooth as possible
- strength
- material thickness increased for longer spans
- greater forces applied to larger pontics
- material thickness increased for longer spans
Describe the different surfaces of a pontic
- occlusal surface
- resembles tooth it is replacing
- narrow if possible to enable cleaning
- sufficient occlusal contact
- approximate surface
- connector must be 2mmx2mm for sufficient strength
- embrasure space can be reduced if highly aesthetic
- more challenging to clean
- buccal and lingual surfaces
- ridge surface
- fitting surface
What are the minimum dimensions for a connector between a retainer and a pontic?
2mm x 2mm
Describe the features of a wash-through pontic
- hygienic/sanitary
- no contact with soft tissues of overlying ridge form
- functional rather than aesthetic
- easy to clean as fluids can pass through
Describe the features of a dome shaped pontic
- torpedo/bullet
- lower incisor, lower premolar and upper molar
- acceptable if occlusal 2/3 of buccal surface visible
- upper 2/3 of pontic look like tooth
- apical 1/3 is narrowed to aid cleansibility
Describe the features of a modified ridge lap pontic
- buccal surface looks like a tooth
- lingual surface cut away
- line contact with buccal aspect of ridge
- problems with food packing on lingual aspect of ridge
Describe the features of a ridge lap pontic
- saddle
- greatest contact with soft tissue
- can be cleansible if carefully designed
- less food packing than modified ridge lap
- must not displace tissue or cause tissue blanching
- highly motivated patient to prevent plaque build up
Describe the features of an ovate pontic
- presses on the ridge
- can mould and shape gingivae
- difficult to clean so only in highly motivated patients
- increased risk of inflammation to ridge
- very good aesthetic result
- may require prescription of Essix retainer with tooth to mould gingivae initially
What are the different options of materials for conventional bridges?
- all metal
- gold
- excellent properties
- not tooth coloured
- nickel/cobalt chrome
- stainless steel
- gold
- metal ceramic
- good strength and aesthetics
- all ceramic
- good option but higher fracture rate
- modern all ceramic bridges starting to rival all metal
- zirconia
- LAVA, Procera
- strongest, reasonable aesthetics
- lithium disilicate
- Emax
- highly aesthetic
- ceromeric
- not typically used now
- porcelain/composite hybrid
- composite to withstand occlusal forces
- porcelain for aesthetics
- BelleGlass, Vectris, Targis Vectris
Where can all metal bridges be used?
- most common in lower posterior area
- subjected to high occlusal forces
- aesthetic demand is low
- gold is particularly malleable
Where can metal ceramic bridges be used?
- most commonly used bridge in the UK
- can be used anywhere in the mouth
- metal substructure provides robustness
- ceramic provides aesthetics
Where can all ceramic bridges be used?
- LAVA 3M ESPE
- 3-4 unit fixed bridge
- maximum span
- milled zirconium oxide frame
- feldspathic porcelain overlying
- can be used anywhere in the mouth
- withstand occlusal forces
- good aesthetics
- similar reduction to MCC
- less destructive preparation
- better mechanical properties of material
- 3-4 unit fixed bridge
- Zirconia
- preparations on casts scanned
- multilayered or ultra translucent multilayer
- milled
- can have layer of feldspathic porcelain overlying
What are implant retained bridges?
- large span bridges
- screw or cement retained
- screw retained
- access holes on palatal aspect
- screwdriver screws bridge into implant
- PTFE tape or cotton wool fill hole
- hole covered with composite
- cement retained
- abutment on implant
- bridge cemented to this
Describe the entire process of conventional bridgework
- mounted study models
- diagnostic wax up and custom impression tray
- not required for all cases
- request construction of vacuum formed stent from lab
- allows reduction to be checked during preparation
- allows for construction of provisional bridge
- select shade
- pre-op putty impression if no laboratory made stent
- occlusal/incisal reduction
- separation of teeth
- parallelism of surfaces achieved
- mesial surfaces
- distal surfaces
- labial surfaces
- consider retentive features
- for short clinical crown height or over tapering
- slots or grooves
- construct provisional bridge
- make impression and occlusal registration
- temporarily cement provisional bridge
- demonstrate cleaning with superfluous
- write prescription for technician
Why is parallelism important?
