PRS02 - Lecture 4 - Advantages and Disadvantages of Bridges/Pontics Flashcards
What are the 2 types of bridges? (recap)
Minimal preparation -> single missing teeth
Conventional -> large span of endentulous areas
What are the advantages and disadvantages of minimal preparation bridges? (1:2)
Advantages
Most conservative bridge - abutment teeth dont need to be extensively prepared
Disadvantages
Debonding
Metal wing is thin (prone to breaking)
What are the advantags and disadvantages of conventional bridges? (3:2)
Advantages
↑ Retention (2 crown prepped abutment teeth)
Ceramic conventional bridges are good for recurrent trauma
Used for a large span of edentulous area
Disadvantages
↓ Minimlaly invasive
Metal conventional bridges can fracture roots of abutment teeth (recurrent trauma)
What are the 3 types of bridge designs? (recap)
Fixed-fixed - parallel abutments
Fixed-moveable - drifted abutments
Cantilever (+ spring cantilever) - only one abutment tooth available
What are the advantages and disadvantages of Fixed-Fixed designs? (2:3)
Advantages (2)
Cross-arch splinting
Ease of handling
Disadvantages (3)
Units need to be cemented at the same time
Bending
Mobility of abutments (due to open margins)
What are the advantages and disadvantages of Fixed-Moveable designs (3:2)
Advantages (3)
Does not require parallel abutments
Units can be bonded separately
↓ Chance of de-bonding
Disadvantages (2)
↑ Space is required
Metal may show occlusally
What are the advantages and disadvantages of Cantilever designs? (3:3)
Advantages (3)
Conservative (only one abutment is required)
↓ Pulp trauma
Re-bonding is possible
Disadvantages (3)
Limited to one pontic
Tilting of abutment (from occlusal forces)
Cant be used for posterior teeth
What is the difference between a cantilver and spring-cantilever design? (2)
Spring-Cantilever
Pontic has a metal connector (bar) that can attach to a tooth several teeth away
What is the advantages and disadvantages of a Spring-Cantilever design? (1:4)
Advantages (1)
Restores spaced dentition
Disadvantages (4)
Restricted to upper incisiors
Food can get trapped under metal connector (difficult to clean)
Metal connector can fracture
Dislodgement of retainer
What are the different types of pontics - advantages and disadvantages? (4)
Hygienic (wash-through) pontics -> no contact with soft tissues -> easiest to clean but ↓ aesthetics (cant be used on anteriors)
Bullet shaped -> slightly makes contact with alevolar ridge but not tooth shaped (limited to areas where the gingival third of the tooth doesnt show.)
Saddle/ridge concave -> largest area of contact with soft tissues, best aesthetics (used for anteriors + posteriors) but hardest to clean.
Ridge-lap (modified ridge-lap) -> Buccal surface looks like natural tooth. Lingual/palatal surface cut away (convex) making it easier to clean.
What are the 7 principles to bridge design?
1) Support - biological vs engineering
2) Conservation of tooth tissue - minimal preparation, cantilever, no, abutments
3) Cleansibility
Spinted abutments harder to clean
Abutments in front easier to clean
Ability of patient to clean
4) Appearance - fixed movable with minor abutment, connectors, partial crowns
5) Patient factors - assess:
Abutment teeth
Length of span
Occlusion
Shape of ridge
6) Predicting final result using - study casts, intra-oral trials, provisional
7) Stages of design process - select:
Abutment teeth
Retainers
Pontic + connectors
Plan occlusion
