Dental materials: Intracanal medicaments

What is Root Canal Treatment and its indications?

The process of removing infected/inflamed pulp tissue from within the dental tooth

Indications of Root Canal Treatment

Deep dental caries that extends to the pulp tissue

A cracked tooth

Traumatic dental injury

Elective, to improve retention of the tooth(crown)

If RCT is not completed in a single appointment antimicrobial agents are recommended for antisepsis, to prevent re-infection of the dental pulp between appointments.

What is Intracanal Medicament

1. Medicaments that are used as interim appointment dressings.

-To reduce inter appointment pain, decrease bacterial count, render the canal contents inert

2. Minimum inter appointment time after placement of medicaments is no less than 14 days(inflammation takes 10-14 days to subside or heal)

3. Prolonged period provides desirable outcomes; most medicaments take 3-4 weeks to reach their maximum concentration within the peripheral dentine

8 Ideal Properties: Intracanal Medicament

Stimulate periapical repair

Reduce periapical inflammation

Should provide prolonged antimicrobial effects

Effective in the presence of pus and organic debris

Capable of diffusion and penetration of dentine

Inexpensive and with long shelf-life

Non irritant to the periapical and periodontal tissues

Non-staining to either the soft tissue or to the tooth

What are the 6 functions of intracanal medicaments?

Prevent re-infection by acting as physical and chemical barrier, if the temporary restoration fails

Prevent inflammatory root resorption

Eliminate remaining viable bacteria in the root canal system not destroyed by the chemo-mechanical preparation.

Assists in elimination of apical exudates

Reduce periradicular inflammation and control post operative pain

Improve the predictability and prognosis of endodontic treatment

Name Antimicrobial substances used as root canal medicaments

Calcium hydroxide

Antibiotics

Non-phenolic biocides

Phenolic biocides

Iodine compounds

Describe Calcium Hydroxide Root Canal Medicament

Calcium hydroxide is the most commonly used interim antimicrobial intracanal medication (temporary root canal filling)

it is effective at inhibiting bacterial growth in root canal

It is best used in ‘weeping cases’ the tooth with constant clear or reddish exudation, large apical radiolucency, often asymptomatic, but it maybe tender to percussion

It provides little benefit to vital pulp.

Mode of Application of Calcium hydroxide

Available in two forms;

Paste form; single paste

Powder form; powder is mixed with sterile water or saline or local anesthetic solution to a creamy consistency, then picked up by a spiral filler and spun into the canal.

6 Properties of intracanal medicaments

Slow acting antimicrobial agent, provides therapeutic effects when placed for at least a day, and effective disinfection of infected necrotic cases is seen in a week

Hydrolyses the lipid component of bacterial lipopolysaccharides,and inhibits inflammatory root resorption

Low solubility in water

Inhibits the activity of osteoclasts due to its high pH (12.5-12.8)

Neutralizes the acidic endotoxins secreted by bacteria

Denatures proteins found in root canal

Mechanism of action and effects of CaOH

The antimicrobial activity of Ca(OH)2 is due to a release and diffusion of hydroxyl ions resulting in high alkaline environment.

Effects of calcium hydroxide

Physical: Acts as a physical barrier for ingress of bacteria. Destroys the residual bacteria by limiting space for multiplication and holding substrate for growth.

Chemical: Provides antiseptic action due to high pH and action against necrotic pulp tissues

Indications of calcium hydroxide

As a inter visit intra canal medicament

In weeping canals, in resorption cases

In the treatment of perio/endo lesions

In partial pulpotomy, in trauma cases

To control exudation

To decrease postoperative pain after over instrumentation, used in combination with ledermix.

Advantages

1.Promotes healing and repair

2.High pH stimulates fibroblasts

3.Initially bactericidal then bacteriostatic

4.Inhibits root resorption

5.Inexpensive and easy to use

6.Neutralizes low pH of acids

Disadvantages

1. Removal after placement is difficult especially at the apical portion

2. Reduces the setting time of zinc oxide eugenol endodontic based cements.

3. Associated with primary tooth resorption