FPD

Question 1

What was the incidence of caries on FPD abutments in Goodacre’s study? Over what time period?

Answer 1

When evaluating caries related to number of abutments affected: 18% (0-27% range)

When evaluating caries according to prostheses affected: 8% (.7-26% range)

Note: PFM studies were AMR, MCR, and resin-veneered metal (no ACRs studied)

Question 2

What are the most common complications for FPDs over a five-year timeframe?

Answer 2

Goodacre:
1) caries
2) need for endo Tx

Pjetursson:
1) abutment tooth devitalization
2) caries

Question 3

What was the instance of porcelain veneer fracture on FPDs in Goodacre’s study?

Answer 3

2%

Question 4

What is the average distance between maxillary canines? What is the distance between Kaitlyn’s?

Answer 4

Average: 31-35mm
Kaitlyn:

Question 5

What is the typical distance from canine cusp tip to maxillary incisal edge? What is Kaitlyn’s?

Answer 5

Average: 7-11mm
Kaitlyn:

Question 6

Where do connectors typically fail?

Answer 6

At the gingival portion, where tensile forces are generated upon occlusal loading

Question 7

What is the best connector shape?

Answer 7

isosceles triangle, with the gingival base having sufficient width in the loading direction to counteract the tensile force

Question 8

How long is the span of this bridge? Talking points.

Answer 8

MEASURE IT– I think it’s about 35mm

Regarding material choice, this is not an unsual distance between implants for a zirconia implant-supported prosthesis, which have excellent survival rates.

Question 9

Do restorations milled from pre-sintered or fully-sintered zirconia show better marginal fit?

Answer 9

fully-sintered

(disadvantage– long milling time and attrition of milling tools)

Question 10

Describe the tissue surface of the pontics.

Answer 10

convex, similar to an ovate pontic design

modified ridge-lap only in position, because they sit slightly anterior to the crest of the ridge in most places for esthetics and lip support

tissue surface is highly polished zirconia, no glaze

Question 11

law of beams

Answer 11

As span length increases, deflection will increase proportional to the cube of the length
As connector height decreases, deflection will increase proportional to the cube of the reduction in connector height.

Question 12

Why do pier abutments fail?
How can you overcome this?

Answer 12

Tension between the terminal retainers and their respective abutments

Can overcome by incorporating a nonrigid connector on the middle abutment to isolate force to the segment of the FPD to which it is applied

Standlee & Caputo

Question 13

Where would you place a keyway on a non-rigid connector?

Answer 13

keyway on the distal of the pier abutment
key on the mesial of the distal pontic

Long axes of posterior teeth usually lean mesially, and vertical forces produce further movement in that direction

Question 14

How is non-rigid connector placement different when connecting an implant to a tooth?

Answer 14

keyway on the implant
key on the pontic

Minimizes risk of intrusion and allows the tooth to move without overloading the implant

Question 16

Success rate of single wing posterior resin-bonded FPDs?

Answer 16

Yazigi & Kern - 100% survival at 4.5 years (mean)