Lesson 12

Question 1

strong, esthetic post and core restoration can be fabricated from strong zirconia with CAD/CAM technology

Answer 1

CAD/CAM ZIRCONIA POST AND CORE RESTORATION

Question 2

replaces the missing coronal tooth structure, in combination with the remaining coronal tissue

Answer 2

CORE FABRICATION

Question 3

→ shaped in resin or wax
→ cast directly onto prefabricated post

Answer 3

CORE FABRICATION

Question 4

make a core from plastic restorative material (amalgam,
composite resin, or glass ionomer)

Answer 4

CORE FABRICATION

Question 5

→ maximum tooth structure can be conserved because undercuts do not need to be removed
→ treatment requires one fewer patient visit

Answer 5

ADVANTAGES of PLASTIC FILLING MATERIALS

Question 6

→ there are fewer laboratory procedures
→ testing has generally revealed good resistance to fatigue
testing and good strength characteristics, possibly because of the good adaptation to tooth structure

Answer 6

ADVANTAGES of PLASTIC FILLING MATERIALS

Question 7

long-term success may be affected by corrosion of amalgam cores, the low strength of glass ionomer or the continued polymerization and high thermal expansion coefficients of composite resin cores

Answer 7

DISADVANTAGES of PLASTIC FILLING MATERIALS

Question 8

microleakage with temperature fluctuations (thermocycling) is greater under composite resin and amalgam cores than under conventional crown preparations (however, the extent of leakage under cast cores has yet to be determined)

Answer 8

DISADVANTAGES of PLASTIC FILLING MATERIALS

Question 9

difficulty may be encountered with certain operative procedures such as rubber dam or matrix application particularly on badly damaged teeth

Answer 9

DISADVANTAGES of PLASTIC FILLING MATERIALS

Question 10

can be performed by combining a prefabricated post with auto polymerizing resin

Answer 10

DIRECT PROCEDURE FOR SINGLE-ROOT TEETH for CAST METAL

Question 11

cast post and core restoration should be slightly undersized in relation to the prepared post space in order to ensure full seating

Answer 11

INVESTING AND CASTING

Question 12

post fit should not be loose that light finger pressure causes rocking, rotation, or wobbling

Answer 12

INVESTING AND CASTING

Question 13

→ tight fit can cause root fracture
→ casting alloy should have suitable physical properties
→ Ni-Cr alloys have high moduli of elasticity and are
recommended for cast posts

Answer 13

INVESTING AND CASTING

Question 14

→ casting defects (small nodules)
→ post insertion resistance
→ the shape of the foundation is evaluated and adjusted as
necessary until tooth preparation geometry is optimal

Answer 14

EVALUATION

Question 15

→ the luting agent must fill all space within the root canal system → voids may be a cause of periodontal inflammation via lateral
canals

Answer 15

CEMENTATION

Question 16

→ a rotary (Lentulo) spiral filler or cement tube is used to fill the
canal with cement

Answer 16

CEMENTATION

Question 17

→ the post and core restoration is inserted gently to reduce
hydrostatic pressure, which could cause root fracture

Answer 17

CEMENTATION

Question 18

use of such venting procedures has also been shown to reduce the necessary seating force, although the latter is probably
cement specific

Answer 18

CEMENTATION

Question 19

• an existing post and core restoration must be removed (ex.: for re-treatment of a failed root canal filling)
• patients must understand in advance that post removal is a risky process and occasionally results in radicular fracture and tooth loss

Answer 19

REMOVAL OF EXISTING POSTS

Question 20

→ thin-beaked forceps will be used if post exposed coronally
→ ultrasonic scaler weakens water-based cement
→ a thin scaler tip or special post removal tip is recommended

Answer 20

REMOVAL OF EXISTING POSTS

Question 21

a post that has fractured within the root canal cannot be removed with a post puller or forceps

Answer 21

REMOVAL OF EXISTING POSTS

Question 22

→ the post may be possible drilled out, but great care is needed to avoid perforation
→ drill out if post has been fractured within the root canal

Answer 22

REMOVAL OF EXISTING POSTS

Question 23

another means of handling an embedded fractured post (described by Masserann in 1966) is to use a special hollow end-cutting tube (or tephrines) to prepare a thin trench around the post

Answer 23

MASSERANN TECHNIQUE

Question 24

retrieval can be facilitated by using an adhesive to attach a hollow tube extractor or by using a threaded extractor

Answer 24

MASSERANN TECHNIQUE