5. Indirect Restorations Flashcards
What are the 7 indications for indirect restorations?
- Repeated failure of direct restorations
- Difficulty achieving adequate tooth morphology via direct techniques
- To minimise risk of tooth fracture
- Aesthetics
- To combine with a removable prosthesis
- For bridge abutment
- To replace an existing crown
What are the 5 contraindications for indirect restorations?
- Poor oral health
- Active disease
- Inadequate crown height
- Inadequate access
- If there is a more minimally invasive option available
What are the 5 steps of a crown preparation?
- Occlusal red auction
- Buccal reduction in 2 planes
- Palatal/ lingual reduction
- Interproximal reduction
- Define margins
What is a shoulder margin cut with?
Square, flat bur end
What is a chamfer margin cut with?
Round bur
How is GP removed for a post crown?
GP is softened with heat/chemicals then removed with a series of gates gladdens burs
How is a post space prepared?
By drilling vertically up and down within the root canal system with a series of burs
How is a resin retained bridge prepared?
- Intra-enamel cingulum rest cut
What are the 4 types of conventional bridge?
Fixed - fixed = abutment teeth at either side of pontic
Cantilever = abutment at one side of the pontic only
Fixed Movebale = ?
Complex = any other?
How is a conventional bridge prepared?
Same way as a crown
What is the 4 step process of preparing a tooth for a crown?
- Take pre-op putty impression and take a shade
- Cut tooth preparation
- Take impressions of preparation using light and heavy body material
- Make temporary restoration using pre op putty and pro temp
List 5 ways to make a temporary restoration:
Putty index + pro temp
Preformed crowns
Pre-op wax up and vacuum formed stent
Free hand
Previous crown
List the 5 materials used for crowns, bridges and veneers
Metal
Metal ceramic
Ceramic
Composite
Acrylic
What margin is required for a metal crown?
Any
What margins are required for a metal ceramic crown?
Shoulder for ceramic portion
Chamfer for metal portion
What margin is required for a ceramic crown?
Chamfer
What margin is required for a composite crown?
Chamfer
What are the 6 principles of tooth preparation?
Conserve tooth tissue
Resistance form
Retention form
Structural durability
Marginal integrity
Preserve the periodntium
What is an inlay?
An indirect restoration that sits on/in the occlusal surface only
What is an onlay?
An indirect restoration that covers the cusps
What are the indications for inlays/onlays?
Weakened teeth
To correct occlusion
To reorganise occlusion
What are the advantages of inlays/onlays?
Protects the cusps
Reduces amount of tooth removal required
What are the disadvantages of inlays/onlays?
Complex to prepare
Complex to fabricate
Expensive
What materials can be used for inlays/onlays?
Good
Ceramic
Composite
What is a core?
A restoration placed in teeth prior to preparation for an indirect restoration.
What are the indications for cores?
Heavily restored teeth
Heavily broken down teeth
What materials can be used for cores?
Amalgam
Composite
GI
GMGI
Compomers
Metal alloys
What is a post?
A post restoration placed within the root canal system to facilitate a core build up if there is insufficient tooth structure to hold a crown.
Where would you place a post crown?
Anterior teeth only
What type of posts are there?
Direct - prefabricated and placed chair side
Indirect - made in lab
What is an articulator used for?
Aims to reproduce the relationship of the jaws in RCP or ICP.
What are the 4 types of articulators?
Simple hinge
Average value
Semi adjustable
Fully adjustable
When would a face bow be used?
When more than one unit is being replaced
Why would a face bow be used?
To allow casts to be mounted on a semi or fully adjustable articulator
What is the purpose of a face bow recording?
To record the relationship of the maxillary teeth to the condylar head in RCP.
