L5: Pulpal reaction to restorative materials

Question 1

what is pulp capping?

Answer 1

A technique used in dental restorations to prevent the dental pulp from necrosis, after being exposed, or nearly exposed during a cavity preparation

Question 2

what are the necessary conditions before pulp capping can take place?

Answer 2

1) Spontaneous pain
- pulp is getting affected, and thus will not survive

2) Swelling
- the infection has passed the pulp, resulting periradicular infection

3) Electrical testing
- check vitality of pulp

4) Blood is pink
- not too affected thus dental pulp capping will work

Question 3

what factors affect the dental pulp reaction to dental caries?

Answer 3

– Anatomical considerations of the lesion location
– Dynamic activity of the carious lesion
– Extend of the lesions
– Age of the pulp

Question 4

what clinical investigations help come up with a pulpal diagnosis?

Answer 4

• Patient description of subjective symptoms
• Pulp sensibility testing
• Radiographic examination

Question 5

what factors can influence the pulp healing process when carrying out a restoration?

Answer 5

• Drill speed
• The use of coolant
• Operator pressure
• Extent of cavity preparation
• Unnecessary iatrogenic removal of dentine
• Extensive and prolonged use of etchants

Question 6

what 2 biological events take place during pulpal repair?

Answer 6

• Progenitor cell recruitment – Reparative dentinogenesis (the ageing population would have a more compromised response)
• Odontoblast-like cell differentiation and stimulation of dentine matrix secretion – Reparative dentinogenesis

Question 7

what happens to the pulp as you age?

Answer 7

pulp tissue becomes more fibrous, and pulp volume reduces (as a result of physiological secondary dentine formation and reactionary dentine over the years)

Question 8

mineral trioxide aggregate

Answer 8

• Fine hydrophilic particles
• Mixed with sterile water
• In a colloidal gel of pH 12.5
• Biocompatible with dental pulp tissues
• Good sealing ability
• Predictable dentine bridge formation

Question 9

what is the difficulty with indirect pulp capping?

Answer 9

hard to know:

• how quickly the caries has spread
• how much teriary dentine has formed
• when to stop excavating

Question 10

Dental pulp is a soft _______ _______surrounded by _______ dentine.

Answer 10

connnective tissue

mineralised

Question 11

What is indirect pulp capping?

Answer 11

Not exposing the pulp, almost completely removing the affected dentin and leaving a thin layer of residual demineralised dentine

Question 12

Why is indirect pulp capping more beneficial?

Answer 12

1) minimally inflamed pulp
2) superior tertiary (reparative) dentine formation
3) less bacterial load
4) a more predictable pulp cap

Question 13

What is the cvek’s approach to pulp capping?

Answer 13

Cvek (1993) suggested that deep carious exposures can be opened up so that 1-3 mm of exposed pulp can be removed

Question 14

What are the advatages of cvek’s approach to pulp capping?

Answer 14

• allows for a good contact between pulp and the capping agent
• removes superficially contaminated pulpal tissue
• reduces the liklihood of chips forming in dentine that are pushed into the pulp tissue, causing a severe inflammatory reaction

Question 15

What material is used for direct pulp capping?

Answer 15

Calcium hydroxide

Question 16

why is CaOH used for direct pulp capping?

Answer 16

1) Initially bactericidal then bacteriostatic
2) Promotes healing and repair
3) High pH stimulates fibroblasts
4) Neutralizes low pH of acids
5) Stops internal resorption 6) Inexpensive and easy to use

Question 17

What are the disadvantages of using calcium hydroxide in pulp capping?

Answer 17

1) Does not exclusively stimulate dentinogenesis
2) Does exclusively stimulate reparative dentine
3) May dissolve after one year with cavosurface dissolution
4) May degrade during acid etching
5) Degrades upon tooth flexure
6) Marginal failure with amalgam condensation
7) Does not adhere to dentine or resin restorations

Question 18

What is Mineral Trioxide aggregate (MTA)?

Answer 18

Material which consists of fine hydrophilic particles, which when mixed with sterile water results in a colloidal gel of pH 12.5.

• This gel solidifies to a hard structure within approximately 4 hours.
• Once set, it has a high compressive strength comparable to IRM

Question 19

Why is MTA used in dental pulp capping?

Answer 19

1) MTA provides dentine bridge formation at the exposed area
2) releases calcium ions and promotes an alkaline pH
3) has a powerful bacteriostatic effect with lower marginal percolation
4) Effective sealing ability
5) Modulates cytokine production
6) Forms HA (or carbonated apatite) on the MTA surface and provides a biologic seal

Question 20

What are the disadvantages of using MTA in dental pulp capping?

Answer 20

1) discoloration potential
- it is a portland cement
2) presence of toxic elements in the material composition
•Difficult handling characteristics
3) long setting time
4) high material cost

Question 21

Why does resin based material result in leakage?

Answer 21

Due to shrinkage, shrinkage stresses and bonding deficiencies

Question 22

How does smear layer affect pulp capping?

Answer 22

Traps small ground particles into tubules covering prepared surface resulting in reduced communication between dentine and pulp

Question 23

How is smear layer removed?

Answer 23

1) Acid-etching

2) Chelating agent
- chelating agents bind with calcium and carry it out of the canal