Restoration of Endodontically Treated Teeth Flashcards
What is the aim of endodontic treatment?
To treat or prevent apical periodontitis.
Restoration should preserve the decontaminated environment.
Finally: Treatment should eliminate infection and protect the decontaminated tooth from future microbial invasion.
What are the reasons for root canal treatment?
Inflammation: mechanical trauma, heat, chemical injury
Infection: Caries, deep cavities, exposure of dentine
What is the success rate of RCT?
Teeth with no preop periapical lesions = 96%
Teeth with pulp necrosis and periapical lesions = 86%
Teeth with periapical lesions undergoing retreatment = 62%
Why does having a precious periapical lesion reduce the success rate of endodontic treatment?
Some bacteria survive intracanal disinfections procedures
Or it could be due to coronal leakage due to secondary intraradicular infection.
How should endodontically treated teeth be evaluated prior to being restored?
Good apical seal
No sensitivity to pressure
No exudate
No fistula
No apical sensitivity
No active inflammation
True or False: Fractures are more common in endodontically treated teeth than teeth with vital pulps.
True
True or False: Dessication or dehydration of teeth after RCT leads to tooth fracture.
Early studies showed there is less moisture content in calcified tissue of pulpless teeth than in vital teeth. In more recent studies there is less dehydration of dentin.
Dehydrated dentin is not weaker than dentin with higher moisture.
Therefore RCT does not decrease hardness.
What is the effect of dessication on teeth?
Dehydration increases stiffness and decreases flexibility of dentin
Dehydration does not appear to weaken dentin structure in terms of strength and toughness
Both compression and tension showed no significant differences between RCT and vital teeth.
How do endodontically treated teeth differ from vital teeth?
No significant differences in punch shear strnegth, toughness, and load to fracture between groups.
Vital dentin was 3.5% harder
Similar biomechanical properties
Are endodontically treated teeth more brittle following endodontic treatment?
No, other factors are more critical to failure.
What happens to tooth structure after RCT?
Aging -> Calcification of peritubular dentin -> Mechanical properties of fracture resistance
Irrigants such as NaOCl and EDTA in high concentrations for prolonged times cause reduced flexural strength, elastic modulus and microhardness
Why are endodontically treated teeth more susceptible to fracture?
In most endo treated teeth there are missing tooth structures caused by caries or existing restorations.
Endodontic access cavity and root canal preparation cause loss of lots of dentin (including anatomical structures: cuspal ridges, roof of pulp chamber, marginal ridges -> Increased risk of tooth fracture)
Lack of protective feedback mechanism in endo treated teeth leading to more occlusal overloading and this leads to more tooth fracture.
Do endodontically treated teeth need crowns?
Coronal coverage restoration (onlays, partial or complete metal crowns, and metal ceramic crowns)
Non-coronal coverage restorations (amalgams and composite fillings, pin coronal buildups
In anterior teeth coronal coverage wasn’t significant but in posterior teeth it did significantly improve clinical success. So use a restoration that provides coronal seal.
What is the effect of losing the marginal ridge in endodontically treated teeth?
Loss of marginal ridge decreases more than 60% of tooth stiffness
When is a post needed?
To provide retention for the core that replaces lost coronal tooth structure and to retain the definitive prostheses.
They are not needed if there is substantial tooth structure after teeth have been prepared.
A post and core may help prevent coronal fractures when the remaining coronal tooth structure is very thin after tooth preparation.
What are the most common applications of posts?
Post + direct restoration: Post is separate from the restoration. If there is leakage bacteria have direct access to the RCS.
Post + core for crown preparation (separate): Crown may leak but bacteria won’t have direct access to the RCS.
Cast post and core in one piece. Give strength and rigidity and are often made of metal alloys such as gold. Work when there is substantial tooth structure left.
