Endodontics of the traumatised immature incisor

Question 1

what is the definition of an immature permanent incisor?

Answer 1

> one where the apex can be considered to be open

Question 2

what is the sequence of root growth from the crown to the apex of a tooth?

Answer 2

divergent > Parallell > convergent

Question 3

what are the challenges of a non-vital immature tooth?

Answer 3

> Compromised crown root ratio

> Thin root dentine walls

> Lack of dentinal stop against which root canal materials can be condensed

Question 4

what is the name of Endodontics which is carried out in a non vital immature tooth to close the root?

Answer 4

> apexification

Question 5

what is apexification?

Answer 5

> RCT of these non vital teeth requires a root end closure technique to form a barrier at apex to enable a root filling to be condensed without going through apex

> old - Calcium hydroxide therapy to induce barrier

> new - Artificial plug (MTA)

Question 6

what is the difference between apexification and apexogenesis?

Answer 6

> apexogenesis aim is to maintain vitality and allow continued root growth (vital pulpotomy)

Question 7

what is the diagnostic pathways for loss of vitality?

Answer 7

> Signs + Symptoms
- Pain, swelling, sinus, TTP, mobility, colour change

> Radiographic examination
- Periapical radiolucency (PAP), arrest of root development

> Sensibility tests
- Negative

> Any doubt of loss of vitality - delay endo Rx
Review 3 mths
Better prognosis if no acute abscess

Question 8

how is an emergency treatment for an acute abscess carried out?

Answer 8

> Ideally full extirpation of pulp and dress with non-setting Calcium Hydroxide paste

> But if acutely tender
- Prescription
- Arrange appt 24 – 48 hrs
- Sedative dressing – e.g. odontopaste

Question 9

what are the aims of CH apexification?

Answer 9

> Creation of a calcific barrier across the root apex

> Allows obturation of canal

Question 10

what is the method of CH apexification?

Answer 10

> Achieved by repeated dressing of non-setting Calcium hydroxide at 3-6 monthly intervals

> Once barrier achieved remainder of canal obturated with thermoplastic GP

> Average 9 months to form up to 3 years

Question 11

what is the plug made out of?

Answer 11

> coarse osteocementum material

Question 12

what is the success of CH Apexification?

Answer 12

> 90% apical closure

> 85% success at 5 years for adequate root filling

Question 13

what are the disadvantages of CH apexification ?

Answer 13

> Multiple visits

> Lengthy treatment - may take up to 30 mths for barrier

> Difficult technique

> Position and quality of barrier unpredictable

> Discolouration

> increase brittleness (risk of cervical #)

> Expensive in terms
1. Clinical time
2. Parent’s time off work
3. Missed school

Question 14

what is the clinical technique of creating an MTA barrier? (consent - interim root canal dressing)

Answer 14

> Consent

> Isolation

> Access cavity

> Widen cervical constriction (Gates Glidden)

> Extirpation of the pulp

> Estimation of full working length (1mm short of radiographic apex

.> Preparation of root canal, sterile water / 0.5% Milton

> irrigation (must avoid extrusion through apex)

> Needle loose and 2-3mm short of working length

> Dry the root canal

> Interim Root canal dressing (CH) +RMGI

Question 15

is the access cavity in an immature tooth larger or smaller than a mature tooth?

Answer 15

> Triangular shaped access (apex towards gingival margin

> Larger than access cavity for mature tooth

Question 16

what is important to remove in a MTA barrier prep?

Answer 16

> remove cervical constriction in the canal

Question 17

what are the key points of canal preparation for MTA barrier? and what instruments are used?

Answer 17

> Straight line access

> May be up to no 140 file

> Ultrasonic activation or bristle brush

> Plugger
Bristle brush
Fine tip for placement of non setting Calcium Hydroxide (eg. typical, calasept, ultrascal)

Question 18

what is the clinical technique for MTA barrier? (review - finish)

Answer 18

> Review in 1-2weeks

> Obturation when
- no clinical signs of PAP
- no radiographic signs of PAP or evidence of healing

> clean dry canal

> Fine tipped MTA carrier

> Ideally using microscope

> Plugger marker 2 mm short of WL

> Careful condensation until 4mm thickness

> Clean canal walls and access (MTA stains)

> Confirm placement with radiograph

> When set obturate (ProRoot
2nd visit reqd)

> Thermoplastic GP- diverging/parallel
Fibrepost

> check radiograph after RCT

> follow up 1 year

Question 19

what are the properties of MTA?

Answer 19

> Hydrophilic

> 5 min working time, sets <4hrs

> pH 12.5

> Non-resorbable

> High biocompatibility

> Compressive strength = reinforced ZOE
=EBA
<amalgam

> Low leakage <Amalgam + IRM

Question 20

what are the advantages of MTA?

Answer 20

> Small number of visits

> Biocompatible

> Low leakage

> Radioopaque

> Better success than CH technique

Question 21

what are the disadvantages of MTA?

Answer 21

> Cost

> Discolouration with poor handling

> No reinforcement of canal

> Contributes to brittleness

Question 22

how to we restore an immature root treated tooth?

Answer 22

> Where no bleaching GP removed to cemento enamel junction = Direct composite crown build up

> avoid conventional posts and crowns

> DT light post - can be considered

Question 23

why would you avoid placement of a post and crown on an immature root treated tooth?

Answer 23

> Short root

> Leaves inadequate root filling

> Fragile canal walls

> High risk of root fracture

Question 24

what is regenerative Endodontics technique?

Answer 24

> Aims to harness potential of stem cells at apical papilla

> Repopulation of root canal space by stem cells from apical papilla

> Cells similar to dental pulp progenitor cells

> Canal repopulated with vital tissue

> Produces further hard tissue of root

Question 25

what are advantages regenerative Endodontic techniques?

Answer 25

> Thicker root

> ↓propensity for root fracture

> Success requires no additional treatment

> ↓risk of reinfection as ↓reaccess

Question 26

what are the disadvantages of the regenerative Endodontics?

Answer 26

> Lack of long term follow-up data

> Not determined stage and duration of pathosis which leads to destruction of stem cells

> Pulp canal obliteration may complicate future endodontics

Question 27

what is the clinical techniques for visit 1 of the regenerative Endodontics technique?

Answer 27

> Consent

> +/-LA estimate

> Rubber dam isolation

> Pulp extirpated with barbed broach (Working length from preop rads)

> Copious irrigation (1.5% sodium hypochlorite) of canals with mild disinfectant 2mm short of apex

> 5ml saline flush

> Dry canal

> Antibiotics sealed into canal (avoid pulp chamber) mixed with sterile water (bi antibiotic paste =)
- Ciprofloxacin
- Metronidazole

> Cotton pellet

> GIC

> Earlier protocols used TAB- discolouration (tri antibiotic paste)
- Ciprofloxacin
- Metronidazole
- Minocycline

Question 28

what is the clinical techniques for regenerative Endodontics techniques at the second visit?

Answer 28

> Visit 2 (2-4 weeks later)

> If no signs/ symps of infection

> Epinephrine free LA

> Rubber Dam isolation

> Irrigate with saline

> Irrigate with 10ml 17% EDTA

> Dry with paper points

> Sharp instrument 2 mm beyond apex to induce bleeding to fill canal

> Induce clot

> Clean coronal portion

> Seal with Calcium silicate cement, GI, Composite

Question 29

when is the follow up for regenerative Endodontics techniques?

Answer 29

> Clinical and radiographic at 6 months

> Clinical and radiographic at 12 months

Question 30

what is the prognosis of Regenerative Endodontic techniques?

Answer 30

> Root development and thickening highly unpredictable

> Until tissue engineering can be translated into practice RET should be limited only to those cases where prognosis of the immature tooth is deemed to be poor with the use of the traditional approach (CH/MTA)