Quiz 4 - Spring Flashcards
Partial coverage retainers are just as retentive as full coverage retainers. True or False?
False, they are less retentive
Retainers with increased axial wall height are more retentive than retainers with decreased axial wall height. True or False?
True
Increased abutment taper increases the resistance and retention of the retainers. True or False?
False, it decreases it
Abutment taper is, of necessity, increased to align abutments and to allow a path of insertion. True or False?
True. This increased axial wall taper can create extra stresses on pulpal tissues.
The taper is less critical with longer teeth for bridges, true or false?
True
What are the three main types of fixed bridges?
- Pier to Pier
- Pier to Pier to Pier
- Cantilever
What is a pier to pier bridge?
Regular bridge – to abutements and pontic
What is a pier to pier to pier bridge?
3 abutements and 2 pontics
5 teeth are a minimum
What is a cantilever bridge?
1 pontic 1 Abutement Disadvantages - forces on the tooth. May increase – cantilever forces Use a cingulum/marginal ridge rest when possible
When doing a cantilever bridge, the pontic should be mesial or distal to the retainer?
The pontic should be mesial to the retainer. Apparently there is more force as you move distally.
Which teeth should you never use as abutments for cantilever bridges?
No lower or upper lateral incisors
From which tooth should you never go more distal with for a pontic with cantilever bridges?
No pontic distal to second premolars
Is it better to restore a bridge in CR or MI for the occlusion?
CR
Many people have anteriorly displaced discs, yet they are still functional for bridge use. True or False?
True. Disc will never be going back to what it was. Will never regain the correct position between the disc and fossa.
What are the characteristics of anteriorly displaced discs in TMJ?
Still will have to determine a reproducible and comfortable position to restore the teeth in that corresponds to their adaptive position the patient has developed do compensate for the displaced disc.
Disc will tend to regenerate well – adaptive joint.
Diagnosis - the mandible will shift – towards to the damaged side. If the LEFT disc is displaced anteriorly – locks the condyle in position – upon opening the right side will open more and the mandible will displace and sift towards the LEFT side
Conical and short roots have the same outlook as normal roots for abutment teeth. True or False?
False, they are not as good.
What is Ante’s Law?
The total periodontal membrane area of the abutment teeth must equal or exceed that of the teeth to be replaced. Or….
The total root surface area of the teeth to be replaced should not be greater than the total root surface area of the abutment teeth
What does the proprioception from the canines help with?
They help disengage the muscles and reduce excursive tooth wear. Premolars do not have proprioception like canines, we want more contact on incisors and canines.
What are the percentages for root surface area for a maxillary quadrant in accordance with Ante’s Law?
Central -10 Lateral - 9 Canine - 14 1st premolar - 12 2nd premolar - 11 1st molar - 22 2nd molar - 22
What are the percentages for root surface area for a mandibular quadrant in accordance with Ante’s Law?
Central -8 Lateral - 9 Canine - 15 1st premolar - 10 2nd premolar - 11 1st molar - 24 2nd molar - 23
What does a conical root do to crestal bone loss?
The conical shape of roots accelerates the negative impact of crestal bone loss, because conical shaped roots have more surface area toward the cervcical aspect of a tooth, and as you lose bone, you lose all that surface area first and all you have left is a skinny apex in bone with minimal surface area
What is the deflection of a fixed dental prosthesis proportional to? And what does that mean?
The cube of the length of its span
Other factors being equal, if a span of a single pontic is deflected a certain amount, a span of two similar pontics will move 8 times as much, and three will move 27 times as much. Deflection means how much it is flexed.
D = F X S^3, What do they stand for?
D = deflection F = force S = span
Excessive span length is a common contraindication for a fixed dental prosthesis. True or False?
True.
What can pier bridges do to end abutments? And what can help minimize this?
Pier abutments can become a fulcrum and loosen end abutments. A nonrigid connector (a key way) or a cantilever can help with this, so you don’t have this massive 5 unit pier bridge
Always, every tooth that is included in a fixed bridge increases the vulnerability of every other tooth that is a part of the same bridge. True or False?
True
What is the definition of a pontic?
An artificial tooth replacing a missing natural tooth that is designed to restore function and appearance
What are the five different types of pontics?
- Sanitary/Hygienic
- Saddle/Ridge-Lap
- Conical/Bullet
- Modified Ridge-Lap
- Ovate/Socketed
Sanitary/Hygienic:
Recommended Location = Advantages = Disadvantages = Indications = Contraindications = Materials =
Recommended Location = Posterior mandible
Advantages = Good access for oral hygiene
Disadvantages = Poor esthetics
Indications = Nonesthetic zones, impaired oral hygiene
Contraindications = Where esthetics is important, minimal vertical dimension
Materials = All metal
Large gap – with large enough space to actually pull out the debris.
Need 2-4 mm between the pontic and a eduntulous ridge
Clean out with waterPik or ProxaBrush (waterpik won’t scrape off plaque)
Saddle/Ridge-Lap:
Recommended Location = Advantages = Disadvantages = Indications = Contraindications = Materials =
Recommended Location = Not recommended Advantages = Esthetic Disadvantages = Not good for oral hygiene Indications = Not recommended Contraindications = Not recommended Materials = Not applicable
Conical/Bullet:
Recommended Location = Advantages = Disadvantages = Indications = Contraindications = Materials =
Recommended Location = Molars without esthetic requirements
Advantages = Good for oral hygiene
Disadvantages = Poor esthetics
Indications = Posterior areas where esthetics is of minimal concern
Contraindications = Poor oral hygiene
Materials = All-metal, metal-ceramic, all-resin