Lesson 11

Question 1

True or false

Inadequate root fillings should be re-treated before fixed prosthodontic treatment is begun

Answer 1

True

Question 2

True or false

Additional retention from posts is rarely need ed in molars

Answer 2

True

Question 3

True or false

FDPs (the bridge) was significantly lower than that of restorations under single crown

Answer 3

True

Question 4

True or false

four to five years after cementation, reported failure rates were significantly higher in male patients than in female patients and failure rates were three times higher in patients older than 60 than for younger patients

Answer 4

True

Question 5

True or false

maxillary failure rates (15%) were three times as high as mandibular failure rates (55%) and more prevalent in lateral incisors, canines, and premolars than in central incisors and molars

Answer 5

True

Question 6

True or false

custom cast post and core restorations exhibited slightly higher failure rates than did amalgam foundations

Answer 6

True

Question 7

True or false

CONSIDERATIONS FOR ANTERIOR TEETH
→ do not always need a complete crown after endodontics except when the size of plastic restorative materials limit their prognosis

Answer 7

True

Question 8

True or false

CONSIDERATIONS FOR ANTERIOR TEETH endodontically treated teeth are weaker or more brittle than
vital teeth

Answer 8

True

Question 9

True or false

CONSIDERATIONS FOR ANTERIOR TEETH endodontically treated teeth may reduce moisture content

Answer 9

True

Question 10

True or false

CONSIDERATIONS FOR ANTERIOR TEETH

cementing a post in an endodontically treated tooth enhances
prognosis but limits endodontic treatment

Answer 10

True

Question 11

True or false

CONSIDERATIONS FOR POSTERIOR TEETH

complete coverage is recommended on teeth with high risk of fracture like maxillary premolar

Answer 11

True

Question 12

True or false

CONSIDERATIONS FOR POSTERIOR TEETH

→ if significant coronal tooth loss has occurred, a cast post and core restoration or amalgam foundation restoration is needed
→ complete coverage gives the best protection against fracture because the tooth is completely encircled by the restoration

Answer 12

True

Question 13

→ minimal tooth structure removal for post space
→ remaining dentin thickness gives fracture resistance of the root
→ thinner dentin walls with thicker post fractures more easily
→ root canal should be enlarged, enough for the post to fit with
strength and retention

Answer 13

PREPARATION OF THE CANAL

Question 14

→ adequate apical seat
→ minimum canal enlargement (no undercuts remaining)
→ adequate post length
→ positive horizontal stop (to minimize wedging)
→ vertical wall to prevent rotation (like a box)
→ extension of the final restoration margin onto sound tooth
structure

Answer 14

FEATURES OF SUCCESSFUL DESIGN

Question 15

→ save as much coronal tooth structure to reduce stress concentration at the gingival margin
→ if more than 2 mm of coronal tooth structure is remaining, the post design has limited role in the fracture resistance of the restored tooth
→ coronal reduction to the gingival level before fabrication of a post and core should be avoided
→ preserving as much coronal structure as possible enhances prognosis

Answer 15

PREPARATION OF CORONAL TISSUE

Question 16

→ extension of the axial wall of the crown apical to the wing tooth structure
→ help bind the remaining tooth structure together, while simultaneously preventing root fracture during function

Answer 16

FERRULE

Question 17

True or false

Anterior crown and the post and core restoration are frequently dislodged simultaneously.

Answer 17

True

Question 18

canals with elliptical cross section must be prepared with usually
6-8 degrees

Answer 18

POST GEOMETRY

Question 19

→ parallel-sides posts are more retentive than tapered posts
→ threaded posts are the most retentive but should ensure
passivity

Answer 19

POST GEOMETRY

Question 20

→ retention increases as post length increases
→ short post will fail while long post will damage apical seal or
increase root perforation

Answer 20

POST LENGTH

Question 21

→ maintain 5 mm apical seal; 1 mm is considered acceptable
→ post should be as long as possible without jeopardizing apical
seal of strength of remaining tooth structure

Answer 21

POST LENGTH

Question 22

→ increasing post diameter to increase retention is not recommended because it weakened the remaining root structure
→ should not exceed one-third of the cross-sectional root diameter

Answer 22

POST DIAMETER

Question 23

→ serrated or roughened post is more retentive than smooth one
→ controlled grooving of the post and root canal increases the
retention of the tapered post

Answer 23

POST SURFACE TEXTURE

Question 24

True or false

adhesive resin luting agent have no potential to improve the performance of post and core restorations

Answer 24

False

adhesive resin luting agent have the potential to improve the performance of post and core restorations

Question 25

→ resin cement is affected by eugenol containing root canal sealer → zinc phosphate and glass ionomer have comparable retentive properties

Answer 25

LUTING AGENT

Question 26

the choice of luting agent may become more important if the post has poor fit within canal

Answer 26

LUTING AGENT

Question 27

→ long post should be avoided → two or more relatively short post in divergent canals, for better retention

Answer 27

RETENTION FORM in POSTERIOR TEETH

Question 28

→ when amalgam is used as the core material, it can be condensed around cemented post or directly into short prepared post space → single metal post will be used if there is reasonable amount of coronal tooth structure cemented into the largest canal → if there is remaining 3-4 mm thickness of coronal tooth structure, post is not necessary

Answer 28

RETENTION FORM in POSTERIOR TEETH

Question 29

→ greatest stress concentrated at the shoulder margin → stresses are reduced as post length increases → parallel-sided posts may distribute stress more than tapered post

Answer 29

In Vitro Studies Conclusions:

Question 30

→ sharp angles should be avoided → high stress can be generated during insertion with smooth parallel-sided post; threaded post shown to distribute stress evenly if post are backed off a half turn → fracture may occur in glass fiber post rather than in the remaining tooth structure

Answer 30

In Vitro Studies Conclusions

Question 31

→ preparation geometry is important to prevent a post with circular cross section from rotating during function → sufficient vertical coronal walls prevent rotation → small groove placed in the canal wall if coronal dentin has been completely lost

Answer 31

ROTATIONAL RESISTANCE

Question 32

→ grooves should be placed where the root is bulkiest → auxiliary pin and threaded post can prevent rotation

Answer 32

ROTATIONAL RESISTANCE

Question 33

TOOTH PREPARATION (3) stages:

Answer 33

Removal of the Root Canal Filling Material Enlargement of the Canal Preparation of the Coronal Tooth Structure

Question 34

o using a warmed endodontic plugger o using a rotary instrument with chemical agents (ex.: eucalyptus oil)

Answer 34

REMOVAL OF THE ROOT CANAL FILLING MATERIAL → (2) methods commonly used to remove gutta-percha

Question 35

range widely in shape and size with varying radiopacity

Answer 35

Prefabricated Posts

Question 36

recommended for roots with circular cross section

Answer 36

Parallel-Sided Prefabricated Posts

Question 37

used for excessively flared canals

Answer 37

Custom Posts

Question 38

→ prepare post space → reduce coronal tooth structure for the extracoronal restoration → reduction depends on type of restoration

Answer 38

PREPARATION OF THE CORONAL TOOTH STRUCTURE

Question 39

readily available

Answer 39

Prefabricated Post

Question 40

wax or resin pattern

Answer 40

Custom Made Post

Question 41

radiographs are not normally necessary to verify post space

Answer 41

PREFABRICATED POSTS

Question 42

(1) Use in canals that have a non-circular cross section or extreme tapered canal (2) Be extra careful on molars to avoid root perforations

Answer 42

CUSTOM MADE POST

Question 43

post is selected to match the dimensions of the canal and only minimum adjustments needed to seat it to the full depth of the post space

Answer 43

PREFABRICATED POSTS

Question 44

→ platinum-gold-palladium → cobalt-chromium → stainless steel

Answer 44

Parallel-Sided Posts

Question 45

→ stainless steel → titanium → non-oxidizing noble alloys

Answer 45

Serrated Posts

Question 46

→ platinum-gold-palladium → titanium alloys

Answer 46

Tapered Metal Posts

Question 47

→ consists of glass or carbon fibers embedded in a resin matrix → less stiffness and strength than ceramic and metal post → improve esthetics but shorter longevity than metal posts → ease of removal if endodontic retreatment is necessary

Answer 47

Composite Posts

Question 48

→ embedded in an epoxy matrix → comparable to carbon fiber post → translucent post is available

Answer 48

Glass Fiber Post

Question 49

→ excellent esthetic properties → high strength, rigid

Answer 49

Ceramic & Zirconia Posts

Question 50

→ made of cast metal or zirconia fabricated with CAD/CAM technology → cast metal post and core made from direct pattern fabricated in the patient’s mouth or indirect patterns fabricated in the lab o direct pattern technique with light polymerizing resin & auto-polymerizing resin is recommended for single canals with good clinical access o an indirect procedure is more appropriate when access is more problematic or for multiple canals

Answer 50

CUSTOM MADE POSTS