Restoration Of RCT Tooth Flashcards
What should you assess radiographically in an RCT tooth?
Root filling - length, quality, obturation Unfolded/missed canals Sclerosis Bone support Crown to root ratio (1:1.5) Radiolucency - healing
What problems can arise after RCT/re-RCT?
Amount of tooth structure remaining
Lack of ferrule
Wide post holes
Fractured instruments, perforations, ledges etc.
Are RCT teeth more brittle than vital teeth?
No.
They have reduced structural integrity which leads to weakening of the tooth.
How long can you leave a root filled tooth unrestored before you should consider re-RCT?
Re-RCT if left any longer than 3 months
What is more important for the apical periodontal health -
Technical quality of the coronal restoration?
Technical quality of the RCT?
Technical quality of the coronal restoration?
What are the restoration options for anterior teeth with intact marginal ridges?
Composite restoration (veneer)
What are the restoration options for anterior teeth with intact marginal ridges & discoloured crown?
Bleaching or
Veneer or
Crown
What are the restoration options for anterior teeth with marginal ridges destroyed?
Post crown
What is the purpose of a post/core?
To gain intraradicular support for a definitive restoration.
Core provides retention for crown
Post retains the core (doesn’t strengthen or reinforce the teeth, the preparation actually weakens the tooth)
What are the components of a post/core?
Post - placed in the root canal
Core - is what the prosthesis is cemented to e.g. Crown
What length of root filling should be left apically when placing a post core?
4-5mm root filling apically
What is a ferrule?
Dentine collar
Encirclement of 1-2mm of vertical axial tooth structure within walls of a crown.
Prevents root fracture.
What are three features of the ideal post?
Parallel sided
- avoids wedging and more retentive than tapered
Non-threaded (passive)
- incorporates less stress to remaining tooth
Cement retained
- acts as a buffer between masticatory forces post and tooth
What materials can be used for posts?
Metals e.g. Cast gold
Ceramics e.g. Alumina, zirconia
Fibre e.g. Glass, Quartz
What types of posts are available?
Prefabricated or custom
Tapered or parallel
Smooth, serrated or threaded
What is a core build up?
Internal part of tooth is built-up with restorative material to replace the lost tooth tissue.
What materials can be used for cores?
Composite - most common, aesthetics, bonds to tooth
Amalgam - requires retention, poor aesthetics, needs 24hrs to set
GI - not used commonly as it absorbs water
What are problems with posts?
Perforation
Core fracture
Root fracture or crack
Post fracture
How can you manage a post perforation?
Repair by periradicular surgery
- if perforation buccal, raise gum flap & trim
Extraction
How can you remove a post?
Ultra-sonics
Masseran kit (like an apple corer)
Eggler (like a corkscrew)
Moskito forceps
Why restore an endodontically treated tooth?
General - function, occlusion, aesthetics
Endo - coronal seal, cuspal protection
What teeth require cuspal coverage after RCT?
Molars - 6x more likely to fracture without cuspal coverage
What crowns are available for RCT teeth?
Metal
Metal ceramic
Ceramic
What clinical factors dictate post design?
Remaining coronal tooth
Root width
Root length
Canal shape
What is the ideal diameter of a post?
1/3rd root width
When are post stresses produced?
During cement action
During masticatory loading
During post-removal
What endodontic failures that can occur?
Instrument failures - stripping, zips, perforation, instrument fracture
Vertical root fractures
Resorption
Development of peri-apical pathology
What should you assess clinically in a RCT tooth?
Coronal seal - leakage? Swelling Sinus TTP Buccal sulcus - TTPalpation Mobility - Grade I, II, III Increased pocketing
When should posts be used in posterior (molars) teeth?
Avoid when possible!!
If no coronal tissue posts may be inserted for a short distance into the largest and straightest root canal (distal roots of L, palatal roots of U)
What is the ideal RCT restoration for premolars?
Cuspal coverage
Post in one canal only if roots are sufficiently long, bulky and straight
What are the advantages of over denture abutments?
Retention of supporting alveolar bone Continued periodontal proprioception Improved support Retention of denture's Denture better able to resist occlusal forces than tissue-borne denture Psychological advantages
