BDS5 lec Flashcards
Conditions that influence tooth survival positively (4)
Ø Restored w crown after RCT
Ø Mesial & distal proximal contacts
Ø Teeth not functioning as an abutment for removable or fixed prosthesis
Ø Non-molar teeth
ESE Guidelines 2006 for favourable ‘successful’ outcome after RCT (4)
absence of pain & other symptoms
absence of swelling
no sinus tract
no loss of function
radiological evidence of normal PDL space around root
Methods of determining RCT outcome (4)
ESE Guidelines 2006 for favourable ‘successful’ outcome after RCT
1) Symptoms:
* Is the tooth comfortable in function?
* Does the tooth feel normal?
2) Signs:
* Swelling
* Sinus tract
* Tenderness
3) Radiological:
Evaluate the radiograph (PA & a BW is needed)
- Quality of root filling length, taper & density
- Periodontal ligament space
- Any radiolucencys:
- Presence, location & nature of image
4) Histology:
* gold standard
* not applicable in everyday practice
* difficulties processing
WHEN do you monitor healing / development of apical periodontitis after completing RCT& direct pulp cap
ESE Guidelines 2006 for favourable ‘successful’ outcome after RCT
RCT:
minimum 1 year & subsequently as required up to 4 years
Direct pulp cap:
6 months & then regular intervals
HOW do you monitor healing / development of apical periodontitis?
ESE Guidelines 2006 for favourable ‘successful’ outcome after RCT
Clinically & radiographs (+/- histological)
Outline favorable outcome (5)
ESE Guidelines 2006 for favourable ‘successful’ outcome after RCT
absence of pain & other symptoms
absence of swelling
no sinus tract
no loss of function
radiological evidence of normal PDL space around root
Outline uncertain outcome (2)
ESE Guidelines 2006 for favourable ‘successful’ outcome after RCT
Radiographic lesion remains the same size or has only diminished
Assess the lesion until it has resolved or for at least 4 years
If persistent for this period, usually assoc w post-tx disease
Outline unfavourable outcome (5)
ESE Guidelines 2006 for favourable ‘successful’ outcome after RCT
tooth has signs & symptoms of infection
radiographically visible lesion has appeared subsequent to tx
radiographic pre-existing lesion has increased in size
radiographic lesion remains the same size or has only diminished (except if lesion was so large & left scar tissue)
signs of continuing root resorption
Conditions necessary prior to insertion of root canal filling (4)
canal must be dried
canal prep must be complete
tooth should be symptom free
soft tissues related to the tooth should NOT show signs
of infection
Types of sealants for obturation (3)
CaOH sealers (sealaplex)
- antimicrobial
- high pH & encourages repair & calcification
BUT
- is not soluble
- bonding between GP & wall is not as strong as resin based
Resin based sealers (AH Plus)
- high bond strength to dentine
- easy flow
- soluable
Bioceramics
- gold standard
- pre-mixed ready to use
- no shrinkage on setting
- antimicrobial, high pH
Reasons for a short EAL circuit (4)
- perforation
- large lateral canal
- touching metal restoration
- canal too moist
What to look out for in a NaOCl incident (5)
- severe pain
- swelling of tissues
- extreme blanching of tissues
- bloody exudate from tissue
- numbness of weakness or facial nerve
Management of NaOCl incident (4)
Irrigate w sterile water
reassure pt
analgesics
immediate referral to A&E / Max-Fax on call, steroids
PROCEDURAL ERRORS IN ENDO (6)
- Incomplete debridement: short working length, missed canals
- Lateral perforation: often due to poor access
- Apical perforation: makes filling difficult
- Strip perforation: = perforation occurring in the inner or furcal wall of a curved root canal, usually towards coronal end
- Ledge formation
- Apical transportation (zipping) / elbow formation (= narrowing of canal, canal becomes hourglass shaped)
Define strip perforation
Strip perforation
= perforation occurring in the inner or furcal wall of a curved root canal, usually towards coronal end
How to diagnose a perforated canal
CLINICAL diagnosis:
- bleeding
- pain
- instrument angle outside access cavity
RADIOGRAPHIC diagnosis:
- radiolucency/change to darker radiodensity
- instrument passing through
Causes of a perforation (5)
IATROGENIC causes
- burs in floor of pulp chamber
- post preparation
- root canal preparation (stripping)
DENTAL causes:
- dental caries
- resorption
Tx aim for managing perforated root canal
seal the area & prevent infection
Tx option for perforations (3)
PREVENTION
- anti-curvature filing
DECIDE RESTORABILITY OF TOOTH
- might be restored w MTA
REFERRAL TO SPECIALIST
Determinants of perforation tx success (3)
- time since occurrence (early repair ideal)
- size (smaller ideal)
- Location (BELOW CRESTAL BONE & AWAY FROM CANAL ORAFICES)
How often do you monitor perforation tx
same as RCT
at least 1 year & subsequently as required up to 4 years
Management of ledge formation
Can be difficult to bypass
Use small file curved at the apex to the working length
& use file to try and file away ledge using EDTA
List 4 other iatrogenic root canal obstructions (4)
- Fractured instruments (esp files)
- Paste & cement root filling materials
- Silver points
- Posts
What is the aim of obstruction removal?
to remove obstruction w/out unnecessary removal of canal walls
& w/out extrusion of material into the periodontal space
How to remove obstructions (10)
1) magnification & light
2) tweezers
3) long neck burs
4) steiglitz forcepts
5) ultrasonics
6) unscrewing posts w screw heads
7) trephination
8) post puller techniques & equipment
9) special instruments (instrument removal system by Dentsply)
10) use of hedstrom files
How can a fractured file be prevented (4)
- correct access cavity design w straight line access of instruments
- use of single-use files (not sterilised files)
- check file before use if it is bent
- as soon as instrument is bent ot twist is unravelled, use a new one
Success rate of RCT & re-RCT
RCT has 85-95% success rate
Re-RCT has 77-80% success rate
Solvents used in re-RCT (2)
eucalyptus oil
chloroform
Stages of surgical endodontics
Root end / apical resection
rectangular 3 sided flap
remove 3mm radicular apex in horizontal cut to avoid leakage using an ultrasonic instrument
seal root end w MTA
Taper & material of K files & rotary files
hand K files:
- 2% taper
- stainless steel
rotary files
- F1 7% taper
- F2 8% taper
- NiTi
Conditions needed for obturation (3)
1) asymptomatic pt & no sinus present
2) canal must be dry
3) biomechanical prep must be completed
Aims of access cavity (4)
1 - achieve straight line access
2 - identify canal orifices & pulp chamber
3 - remove entire roof/contents of pulp chamber
4 - convergent walls in apical direction
How would you maintain good coronal seal during & after RCT (4)
During RCT:
- removal of caries
- restore during interim (GIC, IRM, ortho band)
- rubber dam
After RCT:
- coronal aspect of root filing is protected (condensed GP 2mm below CEJ, covered by restorative material
- sound coronal restoration (preferable indirect resto for added strength in posteriors)
Properties of irrigant (6)
- non-toxic & non-irritant
- antibacterial - “kills the bugs”
- removes smear layer (inorganic)
- dissolve necrotic tissue & organic tissue remnants
- acts as lubricant
- no adverse effects on sealing ability
- prevents blockages
