Restoration of Endodontically Treated teeth Flashcards
What do you assess on an endodontically restored tooth?
Coronal seal
Amount of remaining tooth structure
Swelling
Sinus
TTP
Tender soft tissues
Mobility
Increased pocketing
What do you look for on a radiograph when assessing a root treatment?
Unfilled/missed root canals
Shape of canal
Bone support
Crown to root ratio
Apical pathology
What are the restorative problems faced after RCT?
Amount of remaining tooth structure
Lack or no ferrule
Wide post holes
Endo complications (Fractured instruments)
Are teeth brittle after endodontic treatment?
No
Are root treated teeth more prone to fracture?
No
Is dentine hardness affected after RCT?
No
Does dehydration affect the hardness of a RCT tooth?
No
What is coronal microleakage?
Ingress of microorganisms into root canal system
What can coronal microleakage cause?
Infection of the apical tissues
Failure of RCT
How do you create a good coronal seal
Trim GP to the ACJ and place RMGI over pulp floor and root canal openings.
What restorations could you give for an anterior tooth with intact marginal ridges?
Porcelain/composite veneer
What restoration could you give for anterior teeth with intact marginal ridges and discoloured crown?
Bleaching or veneer crown
What restoration could you give for anterior tooth with marginal ridges destroyed?
Core build up for crown
Post crown
What prep modificaiton is required for a direct post?
A ferrule
What does a post/core do?
Gain intraradicular support for definitive restoration, and provides retention for crown retains the core.
When do you avoid placing a post/core?
If sufficient coronal dentine present mandibular incisors (thin roots) curved canals (avoid perforations)
Wow long should the root filling length be when placing a post?
4-5mm apically
How wide should the post be for a post crown?
No more than 1/3 of root width at narrowest point and 1mm of remaining circumferential coronal dentine
What should the minimum post length to crown ratio be?
1:1
How much ferrule do you need for a post/core crown?
1.5mm height and width
What is a ferrule?
Dentine collar - encirclement of 1-2mm of vertical axial tooth structure within walls of a crown
What is the purpose of a ferrule?
Lowers risk of root fracture and increases crown retention.
When is the risk of root fracture significantly increased
If a crown margin is not placed onto solid tooth
How can you achieve a ferrule if there there is not enough coronal dentine?
Orthodontic extrusion or crown lengthening
How deep should a post go for a post crown?
At least halfway down the root to ensure good alveolar bone support
What is the ideal post in a post crown?
Parallel sided
Non-threaded
Cement retained
What does a parallel sided post avoid?
Wedging
What does a non-threaded post allow?
Less stress to remaining tooth structure
What categories are post crowns classified into?
Manufacturer
Material
Shape
What are the different types of manufactured post crowns?
pre-formed or custom made
What are the materials available for post crowns?
Cast metal
Steel
Zirconia
Carbon/glass fibre
What are the shapes that a post crown can have?
Parallel sided or tapered
What are the advantages of prefabricated posts?
Only 1 visit required
No impressions or lab needed
Chairside core build up
Immediate preparation of core
Large selection of designs and materials
How are custom posts made?
Impressions/casts from patients mouth
Typically how many visits are needed for custom posts?
2
What material are cast posts made in?
Type 4 heat hardened gold
What are the properties of metal posts?
Poor aesthetics
Lower root fracture risk
Corrosion resistant
Radiopaque
What are the properties of ceramic posts?
High flexural strength and fracture toughness
Favourable aesthetics
Difficult retrievability
Root fracture more common
What are the properties of fibre posts?
Flexible
Similar mechanical properties to dentine
Aesthetic
Retrievable
Bond to dentine with DBA
Radiolucent
What is a core build up?
Internal part of tooth built up with restorative material to replace lost tooth tissue
What does the core of a core build up provide?
Retention and resistance for definitive restorations
What materials are used for core build ups?
Composite
Amalgam
Glass ionomer
What is a nayyar core?
RCT removed from canals amalgam packed into canals, then tooth built up
What considerations do you need to think of when deciding what restoration to choose?
How long the post is
Is there a ferrule
How wide is the post
Is there 3-5mm remaining GP in canal
How straight is the canal
How much space for the core
How much taper is needed for a core?
6 degree
How much GP is left in apical third of canal?
3-5mm
How do you remove GP for a post crown?
Dental dam
Gates gliddens size 3
Working length and rubber stop
How much space should be left in the occlusion when a crown is placed?
2mm
What is the process for trying in a post?
Irrigate with chlorhexidine
Dry with paper points
Ensure fits around prep
Ensure enough occlusal clearance
What complications can arrise from posts?
Perforation
Core fracture
Root fracture
Crack/fracure in post
How would you manage a post perforation?
Repair internally or extract the tooth.
What can be used to remove a post
Ultrasonics
Masseran kit
Moskito forceps
What are the reasons for post failure?
Restorative reasons
Periodontal problems
Endodontic reasons
Heavy occlusal load/abnormal occlusion
