Y2 S3 Pulp exposure: direct pulp capping

Question 1

What is direct pulp capping?

Answer 1

A method designed to preserve pulp vitality through hard tissue repair of an open pulp exposure.
Aka “the application of a biomaterial directly onto the exposed pulp, prior to immediate placement of a permanent restoration”.

Question 2

What is the rationale behind direct pulp capping?

Answer 2

• Pulps under deep carious lesions are inflamed because of microorganisms and their by-products
• When the inflammation is reversible it may be controlled by removal of microorganisms and the restoration of the tooth to prevent further contamination
• Exposed pulps can be protected by various materials

Question 3

What are the requirements of the material used for direct pulp capping?

Answer 3

• Biocompatible
• Bactericidal
• Ideally provide a seal against further microbial or substrate ingress

Question 4

What is a class I pulp exposure?

Answer 4

• Non-carious exposure
• No preoperative presence of a deep carious lesion
• Iatrogenic or traumatic exposure
• Pulp exposed through sound dentine, and the underlying pulp tissue is healthy

NB: these flashcards are based on class I exposures.

Question 5

What is a class II pulp exposure?

Answer 5

• Preoperative presence of a deep or extremely deep carious lesion
• Pulp exposed through a zone of bacterial contamination with an expectation that the underlying pulp tissue is inflamed
• Direct pulp capping is not possible, a pulpotomy is required

Question 6

What type of tooth would be suitable for direct pulp capping?

Answer 6

• Class I exposure with reversible pulpitis
• Lesion of pulp exposure should be small and in caries free dentine
• Bleeding should be arrested

Question 7

Explain the treatment steps for a class I pulp exposure suitable for direct pulp capping.

Answer 7

1) Apply rubber dam and maintain a saliva free operating site
2) Clean pulp wound and tooth tissue with sterile saline
3) Disinfect with cotton wool moistened in sodium hypochlorite (NaOCl) to establish haemostasis, destroy microorganisms and remove dentine debris
4) Place hydraulic calcium silicate on exposed pulp: MTA (followed by GIC/PolyF) or Biodentine
5) Restore tooth with high quality restoration (if MTA used for previous step must place permanent restoration at second visit)
6) Long term follow-up to monitor pulp condition and root development

Question 8

Describe calcium hydroxide (Dycal).

Answer 8

A historical material that has now been replaced by hydraulic calcium silicates (MTA and BioDentine).
- High pH
- Induces hard tissue deposition, dentine bridge forms over exposed pulp
- Antimicrobial
- Does not create a good seal or prevent micro-leakage, so a material must be placed on top e.g. GIC, PolyF

Question 9

Describe how calcium hydroxide leads to dentine bridge formation.

Answer 9

• Layer of liquefaction necrosis forms under the calcium hydroxide
• Necrotic tissue beneath the material becomes diffusely calcified and hard tissue formation occurs beneath which develops into a dentine bridge
• Dentine bridge formation occurs in 50-90% of cases, however the bridges are not of the best quality and can be quite porous, there are often tunnel defects

Question 10

List the disadvantages of calcium hydroxide.

Answer 10

Question 11

Name 2 hydraulic calcium silicate cements.

Answer 11

• MTA
• BioDentine

Question 12

What are the benefits of hydraulic calcium silicate cements?

Answer 12

• Prevent microleakage
• Biocompatible
• Promote regeneration of tissues

Question 13

What material do the ESE recommend following pulp exposure?

Answer 13

A hydraulic calcium silicate material should be placed directly onto the exposed pulp.
For pulp capping, partial pulpotomy or full pulpotomy.

Question 14

What are the advantages of direct pulp capping?

Answer 14

• Decent sucess rates for class I exposures
• Relatively simple procedure

Question 15

What are the disadvantages of direct pulp capping?

Answer 15

• Inability to correctly diagnose pulp condition in every case, cannot 100% diagnose reversible pulpitis
• Operative procedures during treatment may actually induce irreversible pulpitis
• Presence of dentine particles may induce increased inflammation, particularly when forced into pulp tissue
• Large exposures are likely to be infected with bacteria and pulp more likely to be damaged by the operative procedure
• Location of exposure: exposures on the axial wall may cause necrosis coronally, blood clots may form, can lead to blood supply problems and potential necrosis
• Inflamed pulps have a poorer outcome than non-inflamed pulps, thus, this technique is controversial following carious exposure and partial pulpotomy may be preferred

Question 16

What factors are important in the success of direct pulp capping?

Answer 16

Presence of micro-organisms and leakage (long-term sealability of coronal restoration) are more important than the choice of capping agent.

Question 17

What is essential when performing a direct pulp cap?

Answer 17

Control of haemorrhage and exudate

Question 18

What are the success rates for direct pulp caps?

Answer 18