4 - Obturation Flashcards
what increases the likelihood of endodontic success?
- absence of a pre-treatment periodical lesion
- root canal fillings with no voids
- obturation to within 2mm of radiographic apex
- adequate coronal restoration
what are the objectives of obturation?
- to achieve a complete seal (apical, lateral and coronal)
why must endodontic treatment include sealing of the root canal system?
- to prevent tissue fluids from percolating in the root canal
- prevent toxic by-products from necrotic tissue and microorganisms regressing into peri-radicular tissues
role of obturation?
- reduces coronal leakage and bacterial contamination
- seals the apex from periapical tissue fluids
- entombs the remaining irritants in the canal (deprives them of nutrients and lets them remain dormant)
what type of seal is ideal?
- fluid tight or bacteria tight seal
challenges of obturation?
- complex canal anatomy
- removal of microorganisms: mechanical cleaning does not remove all irritants from the canal (many surfaces untouched by file)
process of successful endodontics?
- diagnosis and treatment planning
- knowledge of anatomy and morphology
- shaping and disinfection of RCS
- obturation
- coronal seal
poor obturated teeth - procedural errors include?
- loss of length (ledging)
- canal transportation
- perforation
- loss of coronal seal
- vertical root fracture
importance of obturation?
- eliminates leakage
- seals apex from peri-apical exudate
- reduces coronal leakage
single visit - when is it acceptable?
- only in certain circumstances
- for teeth with vital pulp tissue, one visit is preferred
why is one visit for obturation preferred for vital pulp tissue?
- bacterial infection is minimal
- prevents possible contamination between visits
- observe aseptic conditions during treatment
guidelines for single visit obturation?
- no significant symptoms
- no significant clinical signs: tooth should not be TTP
- canal must be clean and dry: no blood, exudate, pus or smell
- appointment time must be of sufficient length
multiple visit - indications?
- presence of acute signs or symptoms
- persistent exudate after drying the canal
- anatomical difficulties
- technical difficulties
- patient or dentist become tired or has lost patience
what is the perceived advantage of obturating over multiple visits?
- allows an antibacterial dressing to be placed in canal between visits
- CaOH paste is known to reduce the number of residual bacteria following cleaning and shaping
interappointment disinfection: what kind of paste used for dressing? how long must dressing be kept?
Cresophene - what kind of compounds does it contain and why should it be avoided?
- CaOH non-setting paste
- dress for at least one week
- phenol compounds. they should be avoided as they are not very effective and very toxic if they contact periradicular tissues
checklist before obturating? what to examine?
- is the pt having any symptoms?
- examine for clinical signs: tooth TTP? sinus healed? temporary dressing still intact?
- place rubber dam to prevent microbial contamination and disinfect crown
- check that the canals are dry with no exudate, pus or bleeding
ideal properties of obturating materials - technical?
- no shrinkage on setting
- no solubility in tissue fluids
- good adhesion/adaptation to dentine
- no water absorption
- no tooth discoloration
ideal properties of obturating materials - biological?
- no allergy for patient or dental staff
- no irritation to local tissues
- sterile
- antimicrobial
- stimulate periradicular healing
ideal properties of obturating materials - handling?
- radiopaque
- sets in adequate time
- easy to apply and remove using heat, solvents or mechanical instrumentation
obturating core materials?
- gutta percha
- silver points
- pastes
gutta percha: composition?
used in what form?
- 19-22% gutta-percha
59-75% zinc oxide
waxes, coloring agents, antioxidants, metallic salts - non-standardized gutta-percha cones sizes F1-F5
silver points:
how does it make obturation easier?
what are the issues with usage?
- its rigidity makes placement easier
- canals often not properly disinfected: leakage and corrosion
- not adaptable to canal therefore seal limited
- can be difficult to remove
- never obturate a silver point re-treatment in a single visit because the flare-up rate is too high
accessory cones - what sized should be used with finger spreader?
should be used with the same size finger spreader
obturating pastes - types?
- zinc oxide & eugenol + formaldehyde (toxic material)
- plastics: resin based
obturating pastes - paraformaldehyde: why was it thought to be beneficial? what happens if extruded?
- it mummifies and fixes pulpal tissue
- causes severe neurotoxicity if extruded
obturating pastes - resins:
- resorcinol-formalin
- epiphany/realseal: polycaprolactone core and sealer material
obturating pastes - resins - resorcinol-formalin:
commonly used where?
sets very hard where? + what does this mean?
what happens if overfilled?
- used commonly in russia, china, india
- sets very hard in coronal part of canal. therefore it will be hard to retreat
- can cause neurotoxicity if over-filled
obturating pastes - resins - epiphany/realseal:
what kind of material?
develop to do what?
- a polycaprolactone core and sealer material
- developed to bond with each other and canal wall to produce a bacteria tight seal with reinforcement of the root
sealers:
- must be used to fill the spaces between what?
- aim for?
- fill the spaces between the gutta-percha cones and between the canal wall to ensure a fluid tight seal
- aim for maximum gutta percha and minimum sealer
cold lateral compaction (obturation) technique?
- LA
- Rubber dam
- disinfect tooth with chx, alcohol
- remove dressing and cotton wool
- irrigate with citric acid to remove CaOH then sodium hypochlorite
cold lateral compaction (obturation) technique - canals are filled with what?
- gutta percha master apical cone
- protaper next matched to apical size
- X2-X5
- 0.02 taper master apical cone (for apical sizes >50)
- sealer
cold lateral compaction with 0.02 taper cones - spreader must fit within how much of working length?
what should be done if this cannot be achieved? why?
- spreader must be within 1-2mm of working length
- preparation should be refined
- as lateral compaction in the apical third will be inadequate
cold lateral compaction: technique?
- dry canal (correct size of paper points)
- mix sealer, have spreader ready (rubber stop slightly short of WL)
- measure MAC to WL and coat in sealer
- insert slowly in canal to WL
- leave 10-15 secs with light lateral pressure
- remove spreader with slight rotation, place accessory cone into channel created
- repeat until no more accessory cones can be fitted
- take obturation verification radiograph
- cut off excess gutta-percha and compact coronal GP using endodontic plugger
cold lateral compaction: except for the apical few mm, the root canal will be more tapered than the gutta percha cone - this space is filled by?
compacting accessory cones that have been lightly coated in sealer
alternative obturation techniques?
- thermoplastic gutta-percha (continuous wave of obturation)
- obturators: thermalfill, guttacore
finishing, sealing access cavity - how?
- remove all sealer and GP from access cavity to amelocemental junction: prevents discoloration of crown
- use cotton wool pledget soaked in alcohol
finishing, sealing access cavity - what is placed over gutta-percha and pulpal floor to minimize coronal leakage? what are the bactericidal by-products?
- vitrebond
- benzene bromine
- benzene iodine
coronal seal - possible reasons why obturated root canals may become reinfected?
- delay in placing permanent restoration
- fracture of coronal restoration or tooth
- cracks within tooth structure or exposed deninal tubules
- poor margins
- recurrent decay
reinfection of the root canal space will lead to?
periradicular periodontitis
definitive restoration: what is used on anterior teeth? and posterior teeth?
- light coloured composite
- restoration on posterior teeth depends on what is needed: crown/onlay?
- usually requires a core buildup in amalgam or composite
classification of endodontic outcomes?
- healed: no clinical signs/symptoms, no radiolucency
- healing: in progress, clinically no signs or symptoms, reduced radiolucency (follow up 4 yrs)
- persistent/recurrent/emerged disease: periapical periodontitis with/without clinical signs/symptoms
what affects periradicular healing?
- accuracy of periapical preparation
- removal of microbes by effective irrigation
- control of obturation
- coronal seal
(success ultimately depends on control of apical infection)
