non-vital Bleaching

Question 1

need for bleaching and though process

Answer 1

treatment choice based on conservation of tooth structure and its effectiveness in lighting tooth discoloration

MOST CONSERVATIVE WAY

Question 2

breakdown of discoloration

Answer 2

external

internal

• systemic factors
• local factors

Question 3

external discoloration comes from

Answer 3

tobacco, colored plaques, food stains, drug stains

Question 4

internal discoloration by systemic is usually caused by?

Answer 4

SYSTEMIC factors like

• porphyria
• AI
• fluorisis
• tetracycline

Question 5

internal discoloration by local factors is usually caused by?

Answer 5

trauma

protein degradation products

pulp remnnants

agents used in RCT

metallic salts (mercury, silver, copper, iodine)

Question 6

iron sulfide?

Answer 6

black compound that resutls from trauma and process of hemolysis

Question 7

etiology of staining from trauma

Answer 7

trauma – RBC– hemolysis – hemoglobin – iron and hydrogen sulfite mack IRON SULFIDE (black compound)

Question 8

iron sulfide from>

Answer 8

iron and hydrogen sulfide

Question 9

when selecting a case keep in mind?

Answer 9

etiology

complete RTC?

intact tooth structure 9like if not enough - not doing internal bleaching – crown may be better choice)

Question 10

contraindications for internal bleaching

Answer 10

1. extensive restoration s
2. crown defects (fractures, hypoplastic enamel)
3. severely underminded enamel
4. discoloration due to metallic salt – like amalagame or silver cone

Question 11

bleaching agents used

Answer 11

1. sodium perborate
2. 3% hydrogen peroxide
3. 30% hydrogen peroxide (superoxol)
4. 3015% carbamide peroxide (Opalescence) – external

Question 12

methods of bleaching

Answer 12

1. thermocatalytic technique (superoxol + heat – in office)
2. waling bleach with sodium perborate and water or sodium perborate and H2O2
3. combination

Question 13

relationship between bleaching and root resorption

Answer 13

Intra-coronal bleaching with H2O2 can be occassionally assoicated with EXTERNAL ROOT RESORPTION

Question 14

PATHOLOGIC MECHANISM associated with intra coronal bleaching and external root resorption

Answer 14

cementum defects - mainly at the CEJ (cemento-enamel junction) signficantly enhances H2O2 seepage

Question 15

CEJ relationships

Answer 15

1. edge to edge
2. overlap
3. GAP
   - why you can get seepage of the material

Question 16

cementum defects occurence? IMPLICATION?

Answer 16

can be up to 25 % in anterior teeth – WHY NEED A BARRIER

Question 17

T/F barrier thickness and its relation to the CEJ is more important than the choice of material in preventing H2O2 seepage? describe

Answer 17

TRUE

• IRM ZOE composite and Glass ionomer can be used as barrier
• should be places 2mm intra-coronal isolating base – at the CEJ level

Question 18

concept of barrier

Answer 18

should block all of dentinal tubules leading from the pulp chamber which reach the tooth hsurface apical to the epithelial attachment – so that the bleaching agents stay inside the access cavity

Question 19

CEJ lower where?

Answer 19

on facial and palatal and higher on the proximals

Question 20

barrier placement

Answer 20

1 mm below and above CEJ so use the labial CEJ as a guide - leaves the proximal dentinal tubules unprotected – as it is higher there

so probe around tooth and measure where CEJ is then place barrier there

Question 21

diagnostic step (step 1)

Answer 21

determine reason and chec vitality of tooth

complete the RCT and retreat if obturation is inadequate

Question 22

record shade?

Answer 22

step 2

Question 23

step 3

Answer 23

measurements of barrier

Question 24

step 4

Answer 24

tooth isolation

Question 25

step 5

Answer 25

access cavity

- if any necrotic tissue there / left - remove this

Question 26

step 6 - remove?

Answer 26

space for barrier material

• remove GP to level of 2 mm BELOW the CEJ so space for barrier material

Question 27

placement of barrier material

Answer 27

1mm above the CEJ uniformly

Question 28

in office thermocatalytic technique usually uses?

Answer 28

30% hydrogen peroxide – heat it up - then cool – heat and cool repeat

Question 29

walking bleach technique

Answer 29

one he recommends

sodium perborate with 30% – becomes a paste -

fill chamber
- seal with cavit

could do more than one application