Deep caries management

Question 1

What should an ideal pulp capping agent be able to do?

Answer 1

• Maintain vitality and not be toxic to pulp
• Stimulate reparative dentine formation
• Bacteriocidal or bacteriostatic in nature and should be able to provide a bacterial seal
• Adhere well to both the dentine and the overlying restorative material
• Resist forces under the restoration during the lifetime of the restoration
• Sterile
• Radio-opaque

Question 2

What are the 3 widely used pulp capping agents?

Answer 2

CaoH2
MTA
Biodentine

Question 3

Why is CaOH2 a good agent?

Answer 3

-Protective barrier for pulpal tissues
-Blocks patent dentinal tubules
- Neutralises attack of inorganic acids and their leached products from certain cements and filling materials
- Induced bridging of exposed pulp with reparative dentine

Question 4

MoA of CaOH2 (OH-)

Answer 4

OH ions not incorporated into the mineral content solely from the dental pulp via blood supply.

Initiator rather than substrate for repair

OH neutralises acids produced by osteoclasts

Optimum pH for pyrophosphatase activity

Increased levels of calcium ion dependant pyrophosphatase

Question 5

MoA of CaOH2 (Ca2+)

Answer 5

Reduce cap permeability

Reduced serum flow

Reduced levels of inhibitory pyrophosphate

mineralisation

Question 6

What is the zone of obliteration?

Answer 6

Pulp tissue in contact with CaOH is usually completely deranged and distorted due to caustic effect of drug

Consists of debris, dentinal fragments, haemorrhage, blood clot, blood pigmentation and particles of CaOH2.

Due to chemical injury as a result of high conc of OH ions and high pressure of medicament appl

Question 7

What is the zone of coagulation necrosis?

Answer 7

Where there is a weaker chemical effect of OH ions - more apical tissues. Firm layer necrosis or mummified zone

Question 8

What is the zone of dentine bridge formation?

Answer 8

Area of mineralisation initiated by CaOH2. No distinct structural configuration present in CaOH2 . 0.3mm to 0.7mm thickness

Question 9

What is the line of demarcation?

Answer 9

Line of demarcation develops between the deepest level and subjacent vital pulp tissue.

Reaction of CaOH2 and tissue protein to form protein globules

Question 10

What is MTA composed of?

Answer 10

Tri/Di calcium silicate, tricalcium aluminate, bismuth oxide for radio-opacity
Grey MTA - Tetracalcium aluminoferrite

Question 11

Setting reaction of MTA

Answer 11

Sets in the presence of blood or water

Porous Calcium silicate hydrogen becomes a hard crystalline structure in 3-4h

CaOH2 increased pH to 12.5

Question 12

What are the advantages of MTA?

Answer 12

Produces more dentinal bridging in a shorter period of time with superior structural integrity and less inflammation compared to CaOH2

More dentinal bridges prevents future penetration of bacteria

Significant antimicrobial properties on some facultative bacteria

Highly biocompatible with pulpal and periodontal tissues

Hydrophilic - sets hard in the presence of water

pH 12.5 - may induce dentinogenesis

Presence of blood has little impact on the degree of leakage of MTA

Question 13

What is biodentine?

Answer 13

Calcium silicate based material used for the repair of perforations and resorption, apexification and root end fillings

Material can only be used in class 2 fillings as a temporary enamel substitute and in large carious lesions as a permanent dentine substitute

Biocompatible and bioactivity of material - preserves pulp vitality and promotes healing process

Question 14

What is the composition of biodentine?

Answer 14

Powder:
Tri/Dicalcium silicate
Calcium carbonate
Zirconium dioxide

Liquid:
Calcium chloride in aq solution with an admixture of polycarbonate

Question 15

What is the setting reaction of biodentine?

Answer 15

Powder dispensed in capsule that is mixed in a triturator for 30s

Hydration of tricalcium silicate procedures, a hydrated calcium silicate gel and calcium hydroxide

Unreacted tricalcium silicate grains are surrounded by layers of calcium silicate hydrated gel - impermeable to water thereby slowing down the effect of further setting reactions

Sets in 10m - no salivary contamination in this time

Question 16

What are the advantages of biodentine?

Answer 16

Biodentine can be used for pulp capping and to bulk fill cavity
- Does not stain tooth
- Excellent radio-opacity
No need for surface prep or tedious bonding for micro mechanical anchorage
Biodentine has higher compressive strength then dentine and preserves pulp and promotes pulpal healing
Microleakage resistance in enhanced by absence of shrinkage due to resin free formula

Question 17

Characteristics of infected dentine

Answer 17

Soft and demineralised teaming with bacteria

Collagen is irreversibly denatured

Cannot remineralise

Soft necrotic tissue followed by dry leathery dentine which flakes away with an instrument.

Dyes - 1% acid red in propylene glycol stains only irreversibly denatured collagen

Question 18

What are the characteristics of affected dentine?

Answer 18

Demineralised dentine not yet invaded by bacteria

Collagen cross linking remains

Can act as a template for remineralisation if appropriate biocompatible material is placed over it

Discoloured and softer than normal dentine that does not flake away easily

Does not stain with caries-detecting dye

Question 19

What is the aim of an indirect pulp cap?

Answer 19

Preserve the vitality of the pulp by completely removing the carious infected dentine followed by placement of a material that would enable to affected dentine to remineralise by stimulating the underlying odontoblasts to form tertiary dentine

Question 20

What must be present for dentine to remineralise?

Answer 20

affected dentine must contain sound collagen fibres and living odontoblastic processes

collagen fibres function as a base to which apatite crystals attach

living odontoblastic processes supply calcium phosphate from vital pulp for remineralisation

Question 21

Why is it better to have a stepwise caries removal approach?

Answer 21

Avoid unintentional pulpal exposure

Dentist can assess the reaction of tooth and changes in carious activity

Opportunity to remove the slowly progressing lesion in slightly infected, discoloured, demineralised dentine before the placement of the final restoration

Final caries excavation is safer in the second sitting and is easier to remove dry carious dentine

Question 22

What amount of remaining dentine has a good prognosis?

Answer 22

0.5-2mm

Question 23

How often should the outcome of pulp therapies be monitored?

Answer 23

Important to review the vital pulp therapy within 6-12 months

Then annually for 3 years

Question 24

What should the review include?

Answer 24

Pulpal status of the tooth
PA status of the tooth
Coronal seal of overlying restoration

Question 25

What can be seen on clinical exam for a favourable outcome?

Answer 25

No ongoing pulpitic symptoms
Surrounding tissues healthy - no TTP

Question 26

What can be seen radiographically for favourable outcomes?

Answer 26

Immature teeth show signs of further root devo

Presence of dentine bridge between the pulp and capping material

Healthy PA tissues

Question 27

What 3 factors affect the prognosis of a pulp cap?

Answer 27

Using aseptic technique - rubber dam isolation and changing burrs

Control of pulp haemorrhage - once haem achieved, blood clot removed to allow for the interface between the pulp cap material and vital pulp tissue

Achieving a coronal seal - prevent marginal microleakage

Question 28

Which factors increase the outcome of a pulpal exposure

Answer 28

Exposure due to trauma v carious exposure

Control of haem in 10m

Size of exposure <1mm

Tx done within 48hrs of exposure