Restoration of Root Treated Teeth

Why are root filled teeth more vulnerable to tooth loss than teeth with vital pulps? (4)

• Post-treatment disease following RCT

• Use of endodontic chemicals

• Dehydration of dentine

• Reduction in the level of proprioception

• Post-treatment disease following RCT

Explain:

• In posterior teeth - loss of marginal ridges and occlusal isthmus leads to weakening of teeth

• More likely to fracture with further loss of tooth structure

• Use of endodontic chemicals

Explain:

• The process of endo tx predominantly results in collagen depletion which affects elasticity of the dentine and predispose to fracture during shearing forces

• Heat created during tx can further denature collagen and dehydrate the tooth structure - affects the biochemical properties of dentine

Sodium hypochlorite over what Conc has a more damaging effect?

EDTA has a prfound effect on what?

What else can reduce flexural strength of dentine?

• 2%

• Dentine substrate

• Calcium hydroxide dressing

• Dehydration of dentine

Explain:

Dehydration of dentine and transformation of collagen fibre structure

• Reduction in the level of proprioception

Why?

What can act as a protective feature?

• Proprioception is reduced after endo tx as a result of pulpal nerves being involved in regulating masticatory loading

• PDL may act as a protective feature

In parafunctional patients what could happen to chewing forces?

• Loading forces can be 6 times the normal chewing force

• Chewing forces can be horizontal

What 2 seals are important when looking at the long term success of endodontically treated teeth?

• Coronal seal and apical seal

• A strong association has been noted between the crowning of endo tx teeth and their long-term survival

Study:

• Results - resto/coronal seal more important than Endo/apical seal - more likely to have better PA

Before restoration, existing endo tx treated need to be assessed carefully:

5 categories of assessment?

• Endo,perio,resto,strat - from endo lectures

• Endodontic evaluation

• Periodontal evaluation

• Strategic evaluation

• Prosthetic consideration

• Esthetic evaluation

What would be included endodontic evaluation? (6)

• Apical seal

• Not TTP

• Not TTPal

• No exudate, fistula, active inflammation

What would be included in Periodontal evaluation? (6)

• Gingival condition - Unstable disease?/Amt of bone loss?

• Biological width - violation of supra-crestal tissue attachment

• Mobility - grade, occlusal trauma

• Furcation defects

• Crown-root ratio

• Root morphology

Prosthetic Evaluation:

• Extent of coronal destruction - Ferrule effect (a band or ring that encompasses the root or crown of a tooth)

• Adequate circumferential supragingival collar of dentine to retain an extra-coronal restoration

What can be used to measure tooth restorability?

What is a min ferrule that is adequate?

2 mm - height and thickness

Other factors to consider before restoration of endo tx teeth in resto evalaution?

• Tooth type - ant or post

• Position in the arch

• Occlusal and prosthetic forces applied to tooth (Parafunction (increased chewing forces and horizontal chewing forces, if opposing tooth is a denture than forces not significant so can go with direct, if opposing tooth is crown or implant then expect heavy forces then go with indirect )

• The material of the antagonist occlusal surface

• Gender and age

• Occlusion

• Oral hygiene

• Saliva flow

What are the other 2 evaluations?

Aesthetic and strategic evaluation

Timing of the restorative procedure:

Factors to consider in terms of timing of the restorative phase of tx? (4)

• Types of restoration planned - direct or indirect

• Quality of root canal filling

• Pre-existing endodontic status

• Position of tooth in the mouth

How to proceed if:

• Previously vital with satisfactory standard RCT and symptom-free?

• Symptomatic and TTP?

• Small pre-existing periapical radiolucency < 2 mm?

• Larger pre-operative periapical radiolucency

• Proceed with final restoration

• Delay the final restoration for a few weeks

• Proceed with final restoration

• Consider short review period (4 months)

What are restoration options for anterioir and posterior teeth?

Anterior teeth: Composite resin resto, veneer, crowns

Posterior teeth: direct resto/amalgam/com, onlays, Crowns

Anterior teeth:

when to use? (3)

How to place?

ADV (4 - what can you do before placement for better aesthetics in discoloured teeth?)

• Minimally to moderately restored, trauma in young patient where the root canal walls are thin, Larger restorations of developing ant teeth

• Directly over the GP, to osseous level, GIC or dual-core composite base

Veneers - composite or ceramic

2 dis?

• Not easy to incorporate the access cavity within such restorations

• The tooth tissue loss means a significant reduction in available surface area to bond

Crowns - PFM or all ceramic

Indications? (2)

compare the two - preps

• Tooth structure remaining not sufficient for direct restoration

Diagram to help decide if to use direct resto, composite using Nayyar core, or post/core and veneers/crown?

Posterior teeth:

Direct resto - Amalgam

ADV? DIS?

Direct restoration - composite restoration?

limited to what surface?

mostly used as a what?

light vs dual core?

composite placed as Nayyar core are termed what?

If auxiliary retention is required, what can be placed?

Occlusal

Core before subsequent crowning

Dual core - if deep problems with light curing

composite dowel-cores

Fibre-post and then composite build-up

Onlay:

What is the material of choice for posterior teeth?

Gold

Which teeth in particular?

• Upper second molars especially where interocclusal space is limited or patient are bruxist

2 adv of gold onlays

1 dis?

• Perseveration of sound tooth structure

• greater strength

• not aesthetic

2 other materials onlays can be made from?

• Composite and ceramic

wax - up chair side - ask pt to bite to give it shape then do a putty indices

Crown:

Materials? (3)

which is most common and what can it be used as?

Gold/PFM/All-ceramic

Diagram for deciding what restoration to do?

Endocrowns?

Survival of endodontically tx tooth:

• Mainly restorative reasons