Role of tricalcium silicates in endodontic therapy

Question 1

What are the tricalcium silicates in dentistry?

Answer 1

MTA

Biodentine

Question 2

Portland cement - what is it?

Answer 2

= A hydrualic cement = hardens by reacting with water but also forms a water resistant product

Question 3

Composition of portland cement?

Answer 3

Mainly tricalcium silicate and a bit of dicalcium silicate
Clinkers are pulverized to form a powder

Powdered clinkers make up over 90% of the final powder
Ca sulphate is added = controls setting time
Up to 5% other constituents (fillers)

Question 4

Composition of MTA?

Answer 4

Same as portland cement but

• Without traces of arsenic and lead
• Addition of bismuth oxide (20%) for radiopacity
• Smaller and more uniform particle size
• Contains less gypsum which is an inhibitor to control working time

Question 5

Properties of Mineral trioxide aggregate?

Answer 5

Biocompatible
Non-toxic
Non-restorable 
No leakage around margins
Very alkaline when mixed with water
Compressive strength equal to IRM 
Bactericidal

Question 6

Uses of MTA?

Answer 6

Root end restorations following apical surgery
Repair of lateral/furcation root perforations
Pulp capping
Apexification in immature roots
Repair of resorption defects

Question 7

How to use MTA?

Answer 7

Mix powder with sterile water in a 3:1 ratio on a glass slab
Nurse will keep adding small amounts of water to keep the handling properties correct
Deliver MTA using instrument
If using internally place a cotton wool pellet in contact with the MTA to allow it to set
If using external to the tooth moisture will be taken from the surrounding tissues

After placement…:
Upon hydration, MTA forms a colloidal gel that solidifies to a hard structure in 3-4 hours
Initial pH of 10.2 hours which rises to 12.5 after 3 hours
Strength increases in the presence of moisture for up to 21 days

Question 8

What is better for pulp capping, MTA or Dycal?

Answer 8

MTA
= Iatrogenic pulp wounds treated with MTA were mostly free from inflam after 1 week and hard tissue formed within 3 months = dentine bridge formation = better pulp response
Dycal = less consistent formation of a hard tissue barrier and inflam present after 1 week

Question 9

Negatives of MTA?

Answer 9

Takes several hours to set 
Can be washed away before it's set 
Handling properties 
Acidic environment will interfere with the setting process placement site needs to be infection free
Cost

Question 10

What does biodentine contain?

Answer 10

The liquid contains

• Calcium chloride as an accelerator
• A hydrosoluble polymer as a water reducing agent

Question 11

Setting period of biodentine?

Answer 11

9-12 mins (initial set)

Question 12

What has a higher compressive strength during setting: Biodentine, Fugi IX, MTA?

Answer 12

Biodentine = reaches dentine's compressive strength after 28 days (also similar hardness, flexural modulus = similar mechanical properties)
Lowest = MTA

Question 13

Positives of biodentine?

Answer 13

Goes into dentinal tubules = bonding to tooth structure
Will not leak much as good seal
Similarities to dentine

Question 14

What has biodentine achieved?

Answer 14

Biodentine = first all in one biocompatible and bioactive crown root dentine substitute to use wherever dentine is damaged

1. Tooth vitality preservation thanks to reactionary dentine genesis
2. Reduction of therapeutic failures thanks to its microleakage resistance
3. Both endo and restorative indications thanks to physical properties similar to human dentine

Question 15

Uses of biodentine?

Answer 15

Bulk restorative material - for permanent dentinal restorations, temporary enamel restorations and endodontic repairs

Question 16

How to manage a pulp exposure with biodentine?

Answer 16

Prepare cavity
Use biodentine as a pulp capping agent and to rebuild the tooth
After at least 48hrs prepare for permanent restoration
Finish