Restoration of the endodontically restored tooth Flashcards
What should you be looking for in your clinical assessment?
- Is the coronal seal adequate, restorations/crowns/leakage/caries
- How much remaining tooth structure is there
- Is tooth restorable and can you isolate with rubber dam
- Swelling
- Sinus
- TTP
- Buccal sulcus tender to palpation
- Mobility
- Increased pocketing (periodontal disease and root fracture)
What is included on radiographic assessment?
- Root filling (length, quality of obturation e.g. any voids)
- Unfilled or missed root canals
- Shape of canal
- Patency (fractured instruments, posts, sclerosis)
- Bone support (mild, moderate, severe)
- Crown to root ratio
- Any pathology (perforations, radiolucency)
What are some problems after RCT/re-RCT for restoration?
- Amount of remaining tooth structure can be little so determines what restoration type can do
- Lack or no ferrule
- Wide post holes with re-RCT
- Endodontic complications like fractured instruments, perforation, short/long root fillings
Are teeth brittle after RCT?
- No
Are root treated teeth more prone to fracture?
- A RCT with minimal loss of dentine no more likely to fracture than vital tooth
After RCT are teeth as hard as non-root treated teeth?
- Dentine hardness not altered
Does dehydration affect the hardness of RCT tooth?
- Dehydration does not appear to weaken dentine structure in terms of strength or toughness
What is coronal microleakage?
- Ingress of oral micro-organisms into root canal system
What can coronal microleakage cause?
how long should tooth be restored post RCT?
- Important cause of RCT failure
- Root filled teeth unrestored for 3 months or longer they should be generally be re-root canal treated
What should you do to reduce coronal microleakage?
- Trim GP to AC
- Place RMGI over pulp floor and root canal openings
- Don’t have lining too thick, allows remainder of pulp chamber for retention and restoration
What can you do if anterior tooth has intact marginal ridges?
- Composite restoration
- Veneer
What can you do if anterior teeth with intact marginal ridges and discoloured crown?
- Bleaching
- Veneer
- Crown
What to do with anterior teeth with marginal ridges destroyed or post core crowns?
- Core build up with crown
- Post crown
What is a post/core?
- Gains intraradicular support for definitive restoration
- Post placed in root canal
- Core what prosthesis is cemented to e.g. crown or bridge abutment
- Core provides retention for crown
- Post retains the core
- Post don’t strengthen or reinforce teeth
- Preparation of root canal for post weakens the tooth
What is the root filling length of post placement?
- 4-5mm root filling apically
What teeth can be used for post placement?
- Incisors and canines but it is not needed if sufficient coronal dentine present
- Premolars (place in widest root canal)
Why should you not place post in mandibular incisors?
- They have thin/tapering/narrow mesiodistal roots
What should you be careful of if placing post in premolars?
- Have small pulp chambers and tapering roots
- Thin in mesiodistal cross-section and proximal invaginations
- Place in widest root canal
- Avoid curved canals to avoid perforations
What is the post width?
- No more than 1/3 root width at narrowest point
- 1mm remaining circumferential coronal dentine
What is the minimum post length/ crown length ratio?
1:1
Is sufficient alveolar bone support needed for post placement?
- Yes
- Need at least half of post length into root
What is the ferrule measurements needed for post placement?
- At least 1.5mm height and width of remaining coronal dentine
What is a ferrule?
- Dentine collar
- Encirclement of 1-2mm of vertical axial tooth structure within walls of a crown
- Prevents tooth fracture
What can happen if a crown margin not placed onto solid tooth?
- Root fracture significantly increased
- Ferrule helps prevent this
- Orthodontic extrusion or crown lengthening might be needed to be done
What are the components of an ideal post?
- Parallel sided
- Non-threaded (passive)
- Cement retained