FIXED PROS

Question 1

Where can ceramics be used in?

Answer 1

veneers, crowns and bridges.

Question 2

Which type of material offers potential for highly aesthetic restorations with close approximation to natural tooth tissue?

Answer 2

Porcelain (ceramic)

Question 3

What is the disadvantage of all-ceramic restorations?

Answer 3

1. Prone to fracture under oral function
2. Require larger reductions in tooth tissue compared to metal restorations.
3. Cost can be high
4. Reduced scope for adjustment or repair

Question 4

Dental ceramics are classified by 4 different compositions, what are they?

Answer 4

1. Glass based ceramics
2. Glass infiltrated ceramics
3. Polycrystalline (non-glass) ceramics
4. Resin-matrix ceramics

Question 5

What are the three main methods of manufacturing ceramics?

Answer 5

1. Sintering: ceramic powder mixed with water is built to the required shape and exposure to high temperature causing partial melting and fusing of particles.
2. Hot pressing/injection moulding – similar to the lost-wax technique. A wax up of the restoration is invested in refractory die and a heated block of ceramics is injected under pressure.
3. Machining – CAD/CAM represents a significant technological advancement with regards to all-ceramic restoration manufacture.

Question 6

Having sharp incisal-occlusal edges on tooth preparations can lead to what?

Answer 6

1. Failure point in the restorative material
2. Stress concentration at the sharp angle

Question 7

What is wrong with having a gutter preparation?

Answer 7

We get a gutter preparation, when trying to create a shoulder margin, whilst using a chamfer bur, instead of a fissure bur.

A gutter preparation would create a lip, this would indicate that too much tooth structure has been removed and would not be suitable for the restorative material.

Question 8

What are the two types of cuspal coverage restoration?

Answer 8

Onlay and Inlay (also ¾ crowns and 7/8 crowns)

Question 9

Why would you use a cuspal coverage restoration?

Answer 9

Cuspal coverage restorations are important to preserve the integrity of a weakened tooth against the forces of occlusion.

Cuspal coverage that conduces to less cuspal deflection and better protection of the remaining tooth tissue is recommended for the reinforcement of the tooth.

Question 10

When would you use cuspal coverage restoration?

Answer 10

When the integrity of a tooth is compromised and more so if occlusal forces are applied or may be used to correct occlusal discrepancies.

Question 11

What are the tooth preparations for an Au cuspal coverage restoration?

Answer 11

• Non undercut cavity walls
• Cuspal coverage (1mm) with functional cusp bevel
• Bevel marginal finish

Mini shoulder finish buccally in lower arch

Question 12

Which aspect of the tooth is covered in a ¾ crown?

Answer 12

Occlusal, palatal medial and distal, but would not cover the buccal aspect.

Question 13

What is the tooth preparation for a ¾ cuspal coverage restoration?

Answer 13

1. 1mm occlusal reduction
2. Functional cusp bevel
3. Chamfer finish on the mesial, palatal, and distal aspect.
4. Buccal cusp is left untouched
5. Proximal groves

Question 14

What are the advantages of having a full coverage or intra-coronal restorations?

Answer 14

1. Protects cups (ct intra-coronal)
2. Reduces sound tooth removal (ct full coverage)
3. Reduces amount of restorative material required e.g. Au (ct full coverage)
4. Easier to inspect margins (ct subging. Full coverage)
5. Potentially better aesthetics buccally (ct full coverage)

Question 15

What are the disadvantages of CT full coverage or only intra-coronal restorations?

Answer 15

1. Complex preparations for clinicians
2. Complex restorations for technician
3. Expense (CT intra-coronal)

Question 16

What materials can be used for construction of an indirect restoration?

Answer 16

1. Gold
2. All ceramic
3. Composite

Question 17

The abutments in conventional bridgework can be implants?

Answer 17

Abutments can only be natural teeth.

Question 18

the teeth that have been prepared to accept the bridge is known as what?

Answer 18

The abutment teeth.

Question 19

The parts of the bridgework that fit over the abutment teeth are known as what?

Answer 19

Retainer/anchor

Question 20

The part of the bridgework that covers the saddle area is known as what?

Answer 20

Pontic

Question 21

The part of the bridge which connects the retainer/anchor to the pontic is known as what?

Answer 21

Connector

Question 22

The edentulous space that is going to be replaced by the pontic is called what?

Answer 22

Saddle

Question 23

There are four types of bridge what are they?

Answer 23

1. Traditional bridge
2. Cantilever bridge
3. Maryland bonded bridge
4. Implant-support bridge

Question 24

Which type of bridge is this?

Answer 24

traditional bridge

Question 25

Which type of bridge is this?

Answer 25

cantilever bridge

Question 26

Which type of bridge is this?

Answer 26

maryland bonded bridge

Question 27

Which type of bridge is this?

Answer 27

implant-supported bridge

Question 28

which of these types of bridges is the most invasive to the least invasive? 1. Traditional bridge 2. Cantilever bridge 3. Maryland bonded bridge 4. Implant-support bridge

Answer 28

1. Implant-support bridge 2. Traditional bridge 3. Cantilever bridge 4. Maryland bonded bridge

Question 29

As you move mesial in the mouth in reference to pontic and bridges, what does this decrease on the tooth structure?

Answer 29

Loading

Question 30

Why do you tend to cantilever mesially then distally?

Answer 30

Occlusal forces are reduced mesially.

Question 31

What do you not want on the pontic once it has been placed in a cantilever design?

Answer 31

No loading in inter cuspal position or excursion on pontic.

Question 32

In certain situations when there are tilted abutments what is an ideal type of bridgework to be used?

Answer 32

Fixed moveable.

Question 33

In a fixed-moveable bridge the seating action must be in favour of a physiological mesial drift?

Answer 33

ideally the female component should be sited where to the male component. Ideally female component sited mesial to mesial component.

Question 34

With a conventional fixed bridge, in reference to the tooth prep. If an abutment tooth didn’t share the same straight-line axis as the other abutment tooth. Then what would you risk doing if you tried to create the same straight-line axis on the other tooth?

Answer 34

Damaging the pulp.

Question 35

What is a resin-retained bridge?

Answer 35

A resin retained bridge is a bridge replacing a missing tooth that relies for its retention on a composite resin cement. It is one of many available dental restoration methods which is considered minimally invasive and conservative of tooth tissue.

Question 36

When would you consider preparation of a tooth, in a resin retained bridge?

Answer 36

We consider that preparation of the tooth is only required to introduce guide planes when the path of insertion is a problem or to enable maximal coverage when the desired extension would otherwise include enamel undercuts.

Question 37

Resin retained bridges rely on what for retention?

Answer 37

rely on composite resin cements for retention.

Question 38

The first type of RBB was the Rochette Bridge, which relied on the retention generated by?

Answer 38

resin cement tags through a characteristic perforated metal retainer.

Question 39

Why should the use of abutments with active periodontal disease should be avoided?

Answer 39

as increased functional loading may increase the rate of periodontal destruction.