Bioactive Materials

Bioactive Materials

• Bioactive materials are materials that elicit a response in living tissue and induce the formation of a bond between tissue and the material.
• The ideal properties of bioactive materials include:
  • Bactericidal and bacteriostatic properties
  • Sterility
  • Stimulation of reparative dentine formation
  • Maintenance of pulp vitality
• Uses of bioactive materials include:
  • Pulp capping material
  • Permanent restorations
  • Dentinal tubule occlusion
  • Prevention of dentinal hypersensitivity
  • Regeneration of bone tissue and promotion of tooth remineralization

Bioactive Materials Examples

• Calcium hydroxide
• Mineral trioxide aggregate (MTA)
• Calcium-enriched mixture (CEM)
• Biodentine
• Inert materials (isobutyl cyanoacrylate and tricalcium phosphate ceramic)
• ActiveTM BioACTIVE restorative material
• Pulpdent (composite resin that releases more fluoride than glass ionomers)
• MTYA1-Ca filler
• Tetracalcium phosphate (TTCP)
• Sol-gel-derived bioactive glass (BAG) ceramic containing silver ions (Ag-BG)
• Calcium phosphate
• Novel endodontic cement (NEC)
• Endo sequence root repair material

MTA (Mineral Trioxide Aggregate)

• Developed by Dr. Mahmoud Torabinejad for use as a dental root repair material
• Composed primarily of:
  • 75% Portland cement
  • 20% bismuth oxide (Bi2O3)
  • 5% calcium sulfate dihydrate or gypsum (CaSO4 ∙ 2H2O)
• Additional minor trace elements may be present
• Properties:
  • Biocompatible
  • Non-resorbable
  • Radioopaque
  • Antimicrobial
  • Compressive strength develops over 28 days
  • Low solubility
  • pH: initially 10.2, after 3 hours: 12.5 (remains constant)
• Uses:
  • Sealing communications between the root canal system and the periodontium
  • Pulpotomy and apexification
  • Apexogenesis (vital pulp therapy)

MTA Properties

• Setting time: 2 hours and 45 minutes
• Expands during setting reaction, increasing sealing ability
• Moistened cotton pellet should be placed in contact with MTA before placement of the permanent restoration

Comparison with Formocresol

• MTA has low toxic effects, increased tissue regeneration properties, and good clinical results
• Formocresol has been criticized for its tissue irritant, cytotoxic, and mutagenic effects
• MTA is applied directly without cotton pellet, reducing the risk of bleeding and reoccurrence of bleeding

MTA Limitations

• Not used in areas open to the oral environment due to solubility in acidic environments
• Not recommended for obturation of primary teeth due to slow resorption
• Not used with anterior teeth due to discoloration potential
• Not used as a permanent filling due to low compressive strength

MTA Drawbacks

• Discoloration potential
• Presence of toxic elements in the material composition
• Difficult handling characteristics
• Long setting time
• High material cost
• Absence of a known solvent for the material
• Difficulty of removal after curing
• Low compressive strength incompatible with restorative indications

Biodentine Overview

• Biodentine is an all-in-one, biocompatible, and bioactive material for dentine replacement, commercially available since 2009.
• Composition: tricalcium silicate, dicalcium silicate, calcium carbonate, iron oxide, and zirconium oxide.

Composition and Manipulation

• Powder: tricalcium silicate, dicalcium silicate, calcium carbonate, and iron oxide.
• Liquid: calcium chloride and hydrosoluble polymer.
• Mixing ratio: 1 capsule powder to 5 drops of liquid.
• Setting time: approximately 12 minutes.

Advantages

• Helps in remineralization of dentine.
• Preserves pulp vitality and promotes pulp healing.
• Replaces natural dentine with similar mechanical properties.
• Better handling and manipulation.
• Reduced setting time.

Dental Applications

Dentine Replacement

• Biodentine can be used as a permanent dentine substitute (base) under composite or amalgam, especially in deep carious teeth.

Pulp Capping

• Can be used as a pulp capping material, encouraging pulp healing and dentin bridge formation.

Pulpotomy

• Used as a vital pulp therapy method, with a higher success rate than MTA.

Repair of Perforations

• Preferred for perforation repair in root canal or pulp chamber floor due to good adhesion to dentin surface and fast setting time.

Repair of Resorption

• Biocompatibility and ability to induce calcium-phosphate precipitation make it suitable for bone tissue repair.

Apexification

• Can be used in necrotic immature teeth, inducing formation of new cementum and periodontal ligament.