Bridges Flashcards
What is a bridge
A bridge is a fixed prosthesis used to replace one or more teeth, which cannot be removed by the patient
What is an abutment tooth
Tooth to which the bridge is attached
How are abutment teeth usually prepared for a bridge
They are usually prepared for a crown
What is a pontic
The artificial tooth that is carried by the prosthesis to replace the missing natural tooth/teeth
What is a saddle
An area of edentulous ridge over which the pontic will sit
What are bridge retainers
A restoration that is cemented onto the abutment tooth
What are bridge retainers usually
PFM
Full veneer crown
3/4 crown
What is a connector
The area of the bridge that joins the pontic to the retainer
What is a unit
A term used to indicate the number of pontics or retainers associated with the bridge
What does the anti indicate
Indicates the length of the bridge
What does the unit number include
The number of retainers and pontics that make up the bridge
Name the 2 main types of bridge work
- Resin bonded bridgework
2. Conventional bridge work
Describe resin bonded bridgeworks
When we have metal wings that is bonded onto the abutment tooth/teeth in order to retain the pontic
Describe conventional bridge
When abutment teeth are crowned and the pontic Is between the crowns
How is conventional bridge retained
Retained on the bridge abutment with a conventional retainer eg full coverage crown
List the indications for conventional bridgework
- Well motivated patient
- Excellent plaque control
- No active carious lesions
- Stable periodontium
- Small edentulous spaces
- Heavily restored abutment
- Replacement bridge work
Name the 2 main designs conventional bridges can have
- Fixed-fixed bridges
2. Cantilever bridges
Describe a fixed fixed design
- Retainer at either side
- Pontic lies between the retainers
- Rigid connector joins Pontic to the retainers
- 4 units or LESS
Give some advantages of fixed fixed bridges
- Robust design for maximum strength and maximum retention
- Most practical design for larger spans
- Splinting of abutment teeth may be advantageous in a patient with stable periodontal disease
Give some disadvantages of fixed fixed bridges
- Preparations need to be parallel which can be difficult to achieve
- Both preparation are destructive
- Cementation problems as bridges must be inserted in one place
- Design is not suitable for abutment teeth that are markedly tilted
How is the abutment tooth prepared for a fixed fixed bridge
The abutment needs full occlusal coverage to prevent occlusal contacts depression the natural tooth contacts
What can happen if the abutment teeth depress natural tooth contacts
The bridge can debond with leakage and caries
Describe a cantilever bridge design
- Retainers only at one end
- Only ONE pontic with a rigid connector
- 2 or more units
- Uses abutment teeth with large root surfaces
Which tooth would be the best abutment to use to replace a 5?
The 6s
Which tooth would be the best abutment to use to replace a 2?
The 3s
Which tooth would be the best abutment to use to replace a 1s?
The other 1
Give some advantages of a cantilever bridge?
- You only need to prepare one abutment tooth so more conservative than fixed fixed
- No paralleling or multiple abutments with 2 unit design
What are the disadvantages of a cantilever bridge design
- Leverage forces on beh abutment tooth limits the span of the bridge to only 1 pontic
- Torquing forces from the occlusion must not act on the pontic
List some materials that were can use in bridge construction
- Metal ceramic (old)
- Silica ceramic
- Zarconia ceramic
- Alumina ceramic
- All ceramic
What is the survival rate of a fixed fixed conventional bridge at 10 years
87%
What is the survival rate of a cantilever conventional bridge at 10 years
80%
How many bridge abutments lose vitality
10-30%
How many bridge abutments fracture over 10 years
2%
How many bridge frameworks/ veneering porcelain fracture over 10 years
3%
Which framework is more problematic: veneering porcelain or metal ceramic
Veneering porcelain fractures more than metal ceramic
How can conventional bridges fail?
- Abutments can lose vitality
2. Abutments can fracture and retainers can de cement
List the indications for adhesive bridgework
- Good oral hygiene/ stable periodontium and no caries
- Unrestored/ minimally restored teeth
- Good quality and quantity of enamel to bond to
- Short edentulous space
- Could be used as an interim for implant therapy restorations
Give some contra indications for adhesive bridge work
- Poor Oral hygiene/ uncontrolled periodontitis and caries
- Poor quality and quantity of enamel to bond to
- Heavily restored teeth
- Parafuncitonal habits
- Bruxists
- Short clinical crown height
How do we prepare teeth for resin bonded bridges
No preparation or VERY minimal preparation of the abutment teeth
What should we limit when preparing abutment teeth for a resin bonded bridge
Limit any preparation to guide planes/removing obstructive undercuts and ensure this is limited to enamel
What do we use to resin the bridge on the abutment teeth
Wing retainers
Describe the wing retainers we use for bridgework
We use rigid non precious wing retainers of at least 0.7-0.8mm thickness
What must we make sure we keep the poetics out of
Excursive contacts
If we were to do a bridge in the posterior portion of the mouth which bridge design would we avoid
Avoid fixed fixed adhesive bridges (we prefer cantilever bridges)
How can we improve aesthetics in a patient who may have alveolar bone damage
Use pink pontic to try aim replace the lost alveolar tissue
List the different pontic designs
- Ridge lap pontic
- Modified ridge lap pontic
- Ovate pontic
Which of the pontic designs is the most aesthetic
Ovate pontic
What are the problems associated with an ovate pontic
Had to achieve good oral hygiene
Which cement do we use to cement bridges
- Panavia F 2.0 (Rely x)
2. Panavia 21
What should we do to the metal wing retainer before cementing
Sandblast them
