Bridgework Flashcards
What is a dental bridge?
Prosthesis which replaces a missing tooth/teeth, and is attached to one or more natural teeth or implants.
Contra indications of bridgework?
Poor pt cooperation
Medical history - metal allergy
Poor OH
High Caries rate
Periodontal disease
Large pulp horns in young patients ‘conventional bridge’
High possibility of further tooth loss in the arch
Poor abutment quality / poor prognosis
Length of a span of bridge is too long
Poor ridge form / tissue or bone loss
Tilting and rotating of teeth
Largely restored dentition
Periapical status - no active endodontic or pulpal disease
Define abutment and Pontic
Abutment = tooth which serves as an attachment for a bridge
Pontic = tooth that is suspended from the abutment tooth / teeth
Define retainer with regards to bridgework
Define connector
Retainer = Extracorornal or intracoronal restorations that are connected to the Pontic, and cemented to the prepared abutment teeth
Connector = component which connects the Pontic to the retainer
Define a pier and a unit
Pier = An abutment tooth which stands between, and is supporting two Pontics. Each Pontic being attached to a further abutment tooth
Unit = either a retainer or a Pontic
What is a fixed - fixed bridge?
Bridge retainer either side of a Pontic
Retainer - Pontic - retainer
Can be adhesive/resin retained or conventional
What retainers are used for conventional and what are used for adhesive bridges
Conventional - crowns
Resin retained - metal NiCr or CoCr retainers
Advantages of a fixed fixed bridge
Robust
Maximum retention and strength
Splinted abutments can help perio cases
Can be used in longer spans
Simple lab work
Disadvantages of fixed - fixed bridgework
Large tooth preparation needed
Prep must be parallel and minimally tapered
Common path of insertion needed for all abutments
What is a cantilever bridge?
Can be fixed -fixed, or resin retained / adhesive
Retainer at only one end
Advantages of cantilever bridge?
More Conservative than fixed - fixed
Straightforward lab work
No need to ensure tooth preparations are parallel
Disadvantages of cantilever bridges
Less retentive than fixed fixed
Must be rigid to avoid distortion
Smaller span
Mesial cantilever is preferred
What is a fixed - moveable bridge?
Rigid connector distal to Pontic,
Moveable connector mesially, to allow for some vertical movement at the mesial abutment tooth
Advantages of fixed - moveable bridge?
Preps don’t require common path of insertion
More conservative
Allows minor tooth movement
Disadvantages of fixed - moveable bridges
Limited edentulous span
More complex labwork
Possible difficulty cleaning between moveable joint
Can’t construct a provisional
What is a hybrid bridge?
One end = conventional
One end = resin retained / adhesive
What is a spring cantilever bridge?
Pontic is attached to the end of a metal arm that runs across the palate, to a rigid connector on the palatal side of a retainer
Advantages of conventional spring cantilever bridge?
Useful if there is spacing between upper incisors
Useful where adjacent teeth are unrestored
Where a posterior tooth would provide suitable abutment - e.g. already has a large restoration or a crown
Disadvantages of conventional spring cantilever
Only used for maxillary incisors
Difficulty cleaning behind palatal connector on the retainer
May irritate palatal mucosa
Difficult to control movement of Pontic due to spring in the metal arm and displacement of soft tissues
How should an abutment tooth be evaluated?
Must be able to withstand forces previously directed at missing teeth
Supporting tissues should be free of inflammation, and healthy
Crown : root ratio
- optimum ratio is 2:3, minimum is 1:1
On an abutment, what should be considered when evaluating it for use in a bridge?
Root configuration
Angulation and rotation of the abutment
Periodontal health of the abutment
Occlusion of the abutment
Quality of enamel
Risk of pulpal damage (high horns in younger pt)
What is the function of the Pontic?
Restore function
Restore aesthetics
Stabilise occlusion
What are the main considerations when selecting a Pontic design?
Cleansability
- smooth and highly polished
- easy to clean
- free of plaque trap surfaces
Appearance
- tooth like
- correct shade
Strength
- longer the span = greater the thickness needed to withstand occlusal forces
What is a wash through Pontic?
No contact with soft tissue
Functional rather than aesthetic
Consider for lower molars