Endo

Question 1

restoration of endodontically treated tooth
radiographic assessment

Answer 1

• inadequate root fillings should be re-treated before restoration
• root filling length, quality of obturation etc - any voids
• unfilled/missed root canals
• shape of canal
• patency - fracture instruments, posts, sclerosis
• bone support - mild, moderate, severe
• crown to root ratio
• any pathology - is periapical radiolucency healing, resorption, perforations

Question 2

problems after RCT/re-RCT

Answer 2

• amount of remaining tooth structure - externally or internally
• restoration type
• lack or no ferrule - fastening/joining object
• wide post holes eg re-RCT
• endo complications - fractured instruments, perforations, short/long root fillings

Question 3

are teeth brittle after RCT and are root treated teeth more prone to fracture

Answer 3

• teeth do not become more brittle
• a root filled tooth with minimal loss of dentine is not more likely to fracture than a vital tooth

Question 4

after RCT are teeth as hard as non root treated teeth
does dehydration affect the hardness of a RCT tooth

Answer 4

• dentine hardness is not altered after endodontic tx
• dehydration does not appear to weaken dentine structure in terms of strength or toughness

Question 5

RCT describe coronal microleakage and timing for completing restoration

Answer 5

• ingress of oral micro-organisms into the root canal system
• important cause of RCT failure
• root filled teeth unrestored for >3 months should generally be re-RCT
• coronal seal very important - more important that technical quality of RCT

Question 6

summary of coronal restoration on RCT

Answer 6

• trim GP to ACJ
• place RMGI over pulp floor and root canal openings
• lining should not be too thick - allowing remainder of pulp chamber for retention and restoration

Question 7

restoration of endodontically treated tooth
anterior restoration options

Answer 7

• intact marginal ridges - composite restoration, (veneer)
• inact marginal ridge and discoloured crown - bleaching or veneer, (crown)
• marginal ridges destroyed - core build-up with crown, post crown
• direct posts - ferrule required
• cast post and cores - no ferrule - not ideal

Question 8

what is a post/core

Answer 8

• function - salvage tooth which has lost significant amount of internal structure, helps anchor crown to tooth
• core provides retention for a crownv- what the prosthesis is cemented onto
• posts retain the core - they do not strengthen or reinforce teeth - placed in the root canal
• gains intraradicular support for a definitive restoration
• preparation of the root canal for a post weakens the tooth

Question 9

guidelines for post placement
tooth type

Answer 9

• incisors and canines - post unnecessary if sufficient coronal dentine is present
• avoid in mandibular incisors due to thin/tapering/narrow roots
• premolars - if post to be placed then place in widest canal - small/thin pulp chambers and tapering roots - AVOID in curved canals to avoid perforations

Question 10

guidelines for post placement
root filling length/post width and length/ferrule

Answer 10

• root filling length - 4-5mm of root filling apically
• post width - no more than 1/3 root width at narrowest point
• 1mm of remaining circumferential coronal dentine
• sufficient alveolar bone support requires - as at least half of post length into root
• minimum 1:1 post length/crown length ratio
• ferrule at least 1.5mm height and width of remaining coronal dentine

Question 11

what is a ferrule

Answer 11

• the amount of tooth structure on the buccal and lingual walls of the prep
• encirclement of 1-2mm of vertical axial tooth structure within walls of a crown
• prevents tooth fracture
• if crown margin is not placed onto solid tooth - root fracture significantly increased
• orthodontic extrusion or crown lengthening may be necessary to achieve this

Question 12

restoration of endodontically treated tooth
dimensions of restorable tooth

Answer 12

• post length below crown equals crown length
• 1mm minimum thickness of dentine
• 3.5mm prep length - 1.5mm core lengt + 2mm post length above crown/dentine height

Question 13

the ideal post

Answer 13

• parallel sided - avoids wedging and more retentive than tapered
• non-threaded (passive) - smooth surface ensures less stress to remaining tooth than threaded (active)
• cement retained - less retentive than threaded posts but cement acts as buffer between masticatory forces and post/tooth

Question 14

classification of posts

Answer 14

• manufacture - pre-formed/prefabricated or custom made
• material - cast metal, steel, zirconia, carbon/glass fibre
• shape - parallel sided or tapered

Question 15

prefabricated posts summary

Answer 15

• only 1 visit required
• no impressions and lab visit required
• chairside core build up
• post and core are different materials
• immediate preparation of core
• large selection of designs and materials

Question 16

custom posts summary

Answer 16

• cast from direct pattern fabricated in pt mouth - eg duralay
• indirect pattern can be fabricated in the lab - impression of post hole and wax-ip of post and core in lab (most common method)
• post and core made of same material
• 2 visits required - impression and fit
• temporisation between visits and lab stages required - risk of contamination of root canal between visits

Question 17

post material

Answer 17

• metal - cast gold, stainless steel, titanium - poor aesthetics, root fracture, corrosion, radiopaque
• ceramics - alumina, zirconia - high flexural strength and fracture toughness, good aesthetics, difficult retrievability and root fracture common
• fibre - glass, quarz, carbon - flexible, similar properties to dentine, aesthetic, retrievable, radiolucent

Question 18

what is a core build-up

Answer 18

• internal part of tooth is built-up with restorative material to replace the lost tooth structure
• provides retention and resistance for definitive restorations

Question 19

core materials

Answer 19

• composite - most commonly used, good aesthetics, bonds to tooth, moisture control required, used with fibre posts
• amalgam - tend to avoid as retention required, poor aesthetic, core cannot be prepared straight away as needs 24h to set
• glass ionomer - not really used as absorbs water and core expands in size

Question 20

describe nayyar core

Answer 20

• root treatment is removed from root canals
• amalgam is packed into root canals and tooth built up
• this provides retention for the amalgam
• cannor be prepared for 24hours until amalgam sets

Question 21

restoration of endodontically treated tooth
design of restoration considerations

Answer 21

• how long will post be
• have you got a ferrule
• how wide
• 3-5mm remaining GP
• is the canal straight
• how much space for the core - factor in type of crown to be placed

Question 22

restoration of endodontically treated tooth
core design

Answer 22

• core taper and length important
• 6 degree taper
• length required - to allow 2mm clearance for MCC

Question 23

restoration of endodontically treated tooth
provisional restoration

Answer 23

• provisional post core crown (temp bond)
• dressing - not aesthetic but might prevent leakage
• essex retainer

Question 24

restoration of endodontically treated tooth
gutta perchal removal summary

Answer 24

• pros and cons of dental dam
• soften GP - heat/solvent
• gates gliden to minimum size 3 - straight part of canal only
• use working length and rubber stop on gates glidden
• leave 3-5mm GP in apical third
• check GP plug remains - loupes, microscope, periapical

Question 25

restoration of endodontically treated tooth anti rotation notch/groove

Answer 25

* if coronal dentine absent then a small vertical groove in the canal can be an antirotational element * located in the bulkiest area of the root - usually lingual

Question 26

restoration of endodontically treated tooth lab prescription

Answer 26

* please construct cast post and core * tell lab para post colour (temp post size) * core 6 degree taper * please leave 2mm space in occlusion for crown * enclosed registration/opposing impression/shade

Question 27

restoration of endodontically treated tooth lab post and core try in

Answer 27

* check post space for temp bond * irrigate chlorhexidine 0.2% * dry with paper points * ensure fits around prep * do you have enough occlusal clearance for crown - min 2mm

Question 28

restoration of endodontically treated tooth fitting lab post and core

Answer 28

* careful not to fill post space with cement - may prevent seating * use firm apical pressure * get rid of excess cement * can then ask lab for provisional acrylic crown * make sure no excess around when taking crown impression/fitting MCC * practice fit sequence

Question 29

problems with posts

Answer 29

* perforation * core fracture * root fracture or crack * post fracture

Question 30

restoration of endodontically treated tooth post removal equiptment

Answer 30

* ultrasonics * masseran kit * eggler * moskito forceps

Question 31

post failure stats

Answer 31

* 60% due to restorative reasons * 32% due to periodontal problems * 85% due to endodontic reasons

Question 32

restoration of endodontically treated tooth post and core summary

Answer 32

* proper assessment of tooth is required - clinically and radiographically * not all RCT that require a crown need a post and core - avoid if at all possible * unified post and core preferred - avoids material interfaces * not all cores need a post

Question 33

Answer 33

Question 34

Answer 34

Question 35

Answer 35

Question 36

direct pulp cap indications

Answer 36

* dentine surrounding exposure is sound * red, homogenous and blood filled tissue is observed on pulp wound surface * no yellowish liquefied areas or dark non-bleeding zones * no dentine chips present on wound * haemostasis can be achieved within 2-3 minutes after rinsing with mild disinectant - chlorhexidine or 1% sodium hypochlorite - apply on sterile cotton pellet

Question 37

direct pulp cap process/materials

Answer 37

* pulp covered with biocompatible/possibly bioactive restorative material * extended to dentine surrounding exposure * calcium hydroxide/CaOh containing bases * mineral trioxide aggregate (MTA) * calcium silicate cements

Question 38

direct pulp cap RMGI

Answer 38

* may be used to cover CaOH * not in contact with pulp * remaining dentine thickness

Question 39

direct pulp cap provisional restorations

Answer 39

* RMGI * zinc oxide eugenol

Question 40

biodentine constituents/function

Answer 40

* calcium silicate * powder mainly tricalcium and dicalcium silicate * zorconium diozide serves as a contrast medium * positive effect on vital pulp cells * stimulates tertiary dentine formation * can be used as direct pulp cap following dentine exposure

Question 41

biodentine mixing/process

Answer 41

* open capsule - 5 drops of liquid into capsule and close * mix in vibrating mixer for 30 seconds * options: * 1. fill entire cavity with biodentine to then reduce to base/dentin level in 2nd visit (48h-6months later) * 2. fill to base/dentin layer and restore with composite 15-20 mins later same appt * sets in about 12-15 minutes

Question 42

biodentine comparison to CaOH

Answer 42

* CaOH does not prevent microleakage due to porosities in newly formed hard tissue (tunnel defects) * high pH of CaOH causes liquefaction necrosis at surface of pulp tissue * biodentine handles easily * mechanically stronger * less soluble * produces tighter seal

Question 43

types of CaOH

Answer 43

* ultracal - non setting * dycal - setting

Question 44

what is ledermix

Answer 44

* dental treatment which combines the antibiotic action of demeclocycline with the anti-inflammatory action of triamcinolone acetonide. * Ledermix is indicated in pulpitis, periapical periodontitis, and hypersensitive dentine.

Question 45

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Question 46

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Question 47

Answer 47