Restoration of endontically restored tooth Flashcards
what aspect of a root canal treatment causes teeth to become more brittle, prone to fracture and decrease in hardness
the very large access cavities
posts and cores
help gain intraradicular support for a definitive restoration
core provides retention for crown and post retains the core
ferrule
dentine collar - encirclement of 1-2mm vertical axial tooth structure
in what teeth should post placement be avoided
mandibular incisors ( thin, tapered narrow mesiodistal roots)
curved canals (prone to perforation)
if placing a post , how much root filling should be left and why
about 4-5mm apically to maintain a good coronal seal
discuss the size of a post
no more than 1/3 of root width at narrowest point
1mm remaining circumferential coronal dentine
sufficient alveolar bone support - at least half of post length into root
minimum 1:1 post length : crown length ratio
discuss the ideal post
- parallel sided rather than tapered (avoids wedging)
- non threaded (passive (threaded means screw like))
- cement retained (acts as buffer for masticatory forces)
discuss metal as a post material
e.g cast gold, stainless steel, titanium
pros: radiopaque on radiographs
cons: poor aesthetics, root fracture risk , corrosion
discuss ceramics as a post material
e.g alumina , zirconia
pros: high flexural strength, good aesthetics, good fracture toughness
cons: difficult to retrieve , root fracture common
discuss fibre as a post material
e.g glass, quartz, carbon
pros: flexible, similar properties to dentine, good aesthetics, retrievable, can bond to dentine with DBAs
cons: radiolucent, require lots of remaining tooth tissue
what is the most commonly used core build up material
composite
nayyar core
root treatment removed from canals
amalgam packed into canals and tooth built up - provides retention for amalgam
Cant be prepared for 24 hours until amalgam fully set
name 3 problems with post crowns
post fracture
root fracture
post perforation
