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BDS4 Restorative > Restoration of Endodontically treated tooth > Flashcards

Restoration of Endodontically treated tooth Flashcards

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1
Q

What should be considered when assessing endodontically treated tooth clinically?

A

Coronal seal - restoration type
-> Leakage/Caries?

Amount of remaining tooth structure- ferrule

Is the tooth restorable?

Can you isolate it with rubber dam?

Swelling

Sinus

TTP- indicates if inflammation in PDL

Buccal sulcus - tender to palpation

Mobility

Increased pocketing – periodontal disease and root fractures

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2
Q

What is the sign of vertical root fracture?

A

Long/narrow pocket not reflected in other areas of mouth

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3
Q

What are we looking for on radiographic assessment of endodontically treated tooth?

A

Root filling - length, quality of obturation (voids)

Unfilled/missed root canals

Shape of canal

Patency - fracture instruments, posts, sclerosis

Bone support – mild, moderate, severe

Crown to root ratio (1:1.5)

Pathology - periapical radiolucency (healing?), resorption, perforations

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4
Q

How doe external root resorption appear in endodontically treated teeth?

A

Lack of conical apex

Moth eaten appearance

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5
Q

What are some of the issues when doing reRCT?

A

Lack of remaining tooth structure- ext/int

Lack of/no ferrule

Wide post holes

Endodontic complications - fractured instruments, perforations, short/long root fillings

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6
Q

How much do certain cavities weaken tooth by?

A

MOD cavity- weakens tooth by 66 %
MO cavity- weaken by 33%

If you cut an access cavity- it takes away large proportion of structural integrity

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7
Q

What is coronal microleakage?

A

Ingress of oral micro-organisms into the root canal system
-> one of main causes of RCT failure

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8
Q

What can be done to prevent coronal microleakage?

A

Root filled teeth unrestored for 3 months or longer should generally be re-root canal treated

Trim GP to the AC and place RMGI over pulp floor and root canal openings

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9
Q

Why is cusp coverage required for endodontically treated teeth in posterior region?

A
  • Prevent coronal microleakage
  • Prevent catastrophic fracture (tooth splits though furcation or breaks underneath alveolar crest)

** RCT must be adequate- disinfected with NaOCl and obturated accurately

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10
Q

What are some of the myths regarding the properties of endodontically treated teeth?

A

More brittle

Prone to fracture

Not as hard

Dehydration affects hardness

-> evidence against all of these claims

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11
Q

What are the treatment options for endodontically treated anterior tooth with intact marginal ridges?

A

Composite restoration- if small B/L access cavity

Veneer (not protective)

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12
Q

What are the treatment options for endodontically treated anterior tooth with intact marginal ridges but discoloured crown?

A

Bleaching

Veneer

Crown

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13
Q

What are the treatment options for endodontically treated anterior tooth with destroyed marginal ridges?

A

Core build up with crown

Post crown

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14
Q

What is required for direct posts?

A

Ferrule

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15
Q

What is the post option if there is no ferrule?

A

Cast post and cores (not fibre)
-> avoid if possible and build up core with composite

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16
Q

What is the purpose of a post core?

A

Gains intraradicular support for a definitive restoration
-> Core provides retention for crown
-> Post retains the core (placed in root canal)

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17
Q

What are the issues with post core crowns?

A

Posts do not strengthen or reinforce teeth

Preparation of the root canal for a post, weakens the tooth

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18
Q

Why may a diaphragm be added to a post?

A

To provide bulk in root that has fractured

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19
Q

In what teeth should posts be avoided?

A

Mandibular incisors- too narrow/tapering roots

Premolar- in maxillary 4s, 75% have 2 canals
-> tapering roots
-> small pulp chambers
-> proximal invaginations

Curved canals- perforation risk

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20
Q

If a post must be put in a molar tooth, where is it best placed?

A

 Put in longest, straightest canal
 Lower molar- distal root
 Upper- palatal root

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21
Q

What are the guidelines for post placement?

A

4-5mm root filling apically- maintains apical seal

Post width
-> No more than 1/3 of root width at narrowest point and 1 mm of remaining circumferential coronal dentine

Sufficient alveolar bone support, at least half of post length into the root

Minimum 1:1 post length/crown length ratio

Ferrule
-> At least 1.5mm height and width of remaining coronal dentine

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22
Q

What is a ferrule?

A

Encirclement of 1- 2 mm of vertical axial tooth structure within walls of a crown

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23
Q

What is the function of a ferrule?

A

Braces crown at neck of tooth- helps prevent fracture, rotational movement and leakage

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24
Q

What can be done if no ferrule is present?

A

Orthodontic extrusion or CLS can be considered (if no other options and meticulous OH)

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25
What are the options for a tooth with ferrule that is hollowed out significantly?
- Fibre post - Composite - Cast post (is this conservative?)
26
How is a post cemented?
Using GI or resin
27
Where should a crown prep finish ideally?
Ideally crown prep finishes on tooth tissue (not always possible)
28
What are the ADV/DIS of DT light posts?
ADV - Are meant to change colour when contact moisture- easier visualisation - Flexes the same as dentine DIS - need enough tooth structure and ferrule - Difficult to take out as they are bonded in with composite - Moisture and technique sensitive
29
What are the features of the ideal post?
Parallel sided - Avoids ‘wedging’ - More retentive than tapered Non-threaded (Passive) -> Smooth surface incorporates 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
30
What are the different types of prefabricated post?
Tapered Smooth Tapered Serrated Tapered Threaded Parallel Smooth Parallel Serrated Parallel Threaded
31
What are the ADV/DIS of prefabricated posts?
ADV Only 1 visit required No impressions and laboratory visit required Chairside core build-up- immediate preparation of core Large selection of designs and materials DIS Post and core are different materials
32
What is the main issue with tapered post?
Wedges on tooth and flexes on biting
33
What are the different types of metal post?
cast gold, stainless steel, brass, titanium
34
What are the ADV/DIS of metal post?
ADV: Radiopaque DIS: Poor aesthetics Root fracture Corrosion Nickel sensitivity
35
What are the different types of ceramic post?
Alumina Zirconia
36
What are the ADV/DIS of ceramic posts?
ADV High flexural strength High fracture toughness Favourable aesthetics DIS Difficult retrievability Root fracture is common
37
What are the different types of fibre post?
glass, quartz, carbon
38
What are the ADV/DIS of fibre posts?
ADV Flexible- similar properties to dentine Aesthetic Retrievable Bond to dentine with DBA’s DIS Radiolucent on radiographs
39
What are the ADV/DIS/recommended uses/precautions for tapered pre-fab posts?
ADV: Conservative High stiffness High Strength DIS: Less retentive RU: Small circular canals Precautions: Avoid excessively flared canals
40
What are the ADV/DIS/recommended uses/precautions for parallel prefab posts?
ADV: High strength Good retention DIS: Expensive Corrosion if SS Less conservative RU: Smaller circular canals Precautions: Exercise care during prep
41
What are the ADV/DIS/recommended uses/precautions for threaded posts?
ADV: High retention DIS: Stresses created can cause fracture RU: When max retention is essential P: Avoid fracture during seating
42
What are the ADV/DIS/recommended uses/precautions for Custom cast post and core?
ADV: Higher strength than prefab DIS: Less stiff Multiple appointments Technically complex RU: Elliptical or flared canals P: Remove nodules before insertion
43
What is a core build up?
Internal part of tooth is built-up with restorative material to replace the lost tooth tissue -> core is prepared- provides retention and resistance for definitive restorations
44
What are the ADV/DIS of composite cores?
ADV: * Tooth coloured- better aesthetics * Bonds to tooth * Immediate prep * On demand set DIS * Technique sensitive- moisture control required
45
What posts is a composite core used with?
FIBRE
46
What are the drawbacks of Amalgam cores?
- Retention required - Poor aesthetics - Must wait a day until you prepare it - Avoid pinned amalgams
47
What is the issue with GIC core?
Absorbs water and core expands in size
48
What is the aim of a core build up?
Make it look like ideal crown prep of unrestored tooth -> 6 degree taper -> 2mm occlusal clearance
49
What is a nayaar core?
Traditionally uses amalgam  Utilises pulp space and some of the root canal system for more retention  Difficult to retreat  Composite can be used- difficult as no colour contrast
50
What is the main advantage or restoring eddo-treated tooth with onlay?
more conservative, removes less tooth structure
51
How is cusp fracture avoided when placing onlay?
Want it to go over cusps -> ensure cusp has been reduced by 2mm as it will fracture if not
52
What are the materials for onlays?
Bell glass- pressed composite Zirconia Gold
53
What is an endo crown?
Indirect version of Nayyar core  Increases surface area for bonding and part in pulp space will give mechanical retention  Difficult to keep dry  Mostly zirconia
54
What is paracore?
Core material which is similar to bulk fill flowable composite
55
What are the features of Smart Dentine Replacement?
- Self-settling properties - Shade is not great - Etch tooth, bond and inject - Stronger than traditional flowable
56
What are some principles to keep in mind when restoring/retreating endodontically treated teeth?
 Do not rush obturation- will take longer to fix it  Spend time on disinfection too (especially if you are putting post in it)  If you are concerned about quality of current RCT, then re-do  Posts are last resort- structural integrity is really poor
57
What are the steps in restorative cycle?
Small filling Large filling RCT Crown Post crown ReRCT / re post crown Extraction -> Aim to stop advancing
58
What can be used to ascertain whether GP plug is still present when placing a post?
- Loupes - Microscope - Radiographs- to check seal
59
What can be used to remove posts?
Ultrasonic Trephan- Masseran Eggler device Moskito Forceps (screw retained) Sliding hammer Anthogyr (Safe relax)
60
What are the features of ultrasonic tips for post removal?
Can be made of SS with diamond/Titanium -> Remove very small bits of dentine
61
What are the features of the masseran trephan?
Cores around post  Can be destructive  Can be combined with ultrasonic
62
What are the problems with post removal?
You can’t remove it Root fracture (immediate or delayed) Render tooth unrestorable Post space too wide You break post
63
What are the issues that can occur when carrying out treatment involving posts?
Perforation Core fracture Root fracture or crack Post fracture
64
What can be done to mitigate perforation?
Use Reciproc motor (electric motor) with post drill- 1000rpm at torque 4 gives more control
65
What are the treatment options for post perforation?
Repair -> Internal -> External- periradicular surgery, restore with MTA Extraction
66
What are the reasons for post failure?
60% due to Restorative reasons (secondary caries, unrestorable tooth etc) 32% due to Periodontal problems 8% due to Endodontic reasons
67
What can be used as a provisional for a post crown?
Provisional post core crown ( Temp bond) Immediate denture Dressing- Not aesthetic but might prevent leakage Essex retainer
68
What are the components of the para post system?
Provisional post Burn out post (not important) Para post drill Impression post
69
What is written in the lab prescription for parapost?
Please construct cast post and core. Para post (colour) Core 6 degree taper Please leave 2mm space in occlusion for Crown Enclosed registration / opposing impression Shade
70
What are the steps in the try-in of a parapost?
Check post space for temp bond Irrigate chlorhexidine 0.2% Dry paper points Ensure fits around prep Do you have enough occlusal clearance
71
What are the steps in the fit of a post?
Be careful not to fill post space with cement -> You may prevent it seating Use firm apical pressure Get rid of excess Can ask lab for provisional acrylic crown Make sure no excess around when taking crown impression / fitting MCC Practice fit sequence

BDS4 Restorative (12 decks)

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