The ideal retrofilling material should have the following characteristics: 

• Capable of guaranteeing a perfect cavity seal 
• Easy to carry and to manipulate 
• Relatively fast setting time 
• Dimensionally stable and nonresorbable 
• Biocompatible 
• Osseo and cementogenic 
• Nontoxic 
• Insoluble in tissue fluids 
• Bactericidal or bacteriostatic 
• Does not stain the root and the surrounding tissues 
• Sterile or easily sterilizable before use 
• Radiopaque 
• Easy to remove if necessary 

Amalgam has been the most commonly used root-end filling material. Its use has been abandoned for many reasons, like toxicity, leakage,  corrosion,  blood mercury level,  tattoos on soft tissue,  microcracks in the root etc.  

Zinc oxide eugenol materialis an alternative to amalgam and it has been recommended as a root-end filling material because of its biocompatibility, marginal integrity etc. Eg. Super EBA 

Mineral Trioxide Aggregate is another material of choice. MTA was originally developed from Portland cement as a grey powder by Dr. Torabinejad (Loma Linda University, CA, USA). Advantages of this material includes biocompatibility, antibacterial properties, marginal adaptation and sealing properties, and its hydrophilic nature. 

Advantages of MTA includes:

• Easy to mix and place into the cavity with a small carrier 
• Since it sets in the presence of moisture, it is not moisture sensitive and is 
• Not affected by blood contamination 
• Seals better than amalgam, SuperEBA or IRM 
• Has a better adaptation to the surrounding dentin 
• Has excellent biocompatibility 
• Activates regeneration of periapical tissues including periodontal ligament and cementum 

Difficulty of handling and staining caused by grey MTA and prolonged setting time are the disadvantages of MTA. 

Recently other bioactive tricalcium silicate and phosphate cements have been introduced, and EndoSequence Root Repair Material (RRM) (Brasseler USA, Savannah, GA, USA) is available. The first generation bioceramic used in dentistry has been MTA, which belongs to the category of tricalcium silicate-base cements. Recently other bioactive tricalcium silicate and phosphate cements have been introduced, and EndoSequence Root Repair Material (RRM) (Brasseler USA, Savannah, GA, USA) is available and populat in clinical use too. Biodentine is another well known root end material. 

Regardless of the size of periapical lesions, persistence of root canal infection is the primary cause of inflamed periapical tissues not to heal after endodontic therapy. 

 Article by Dr. Siri P. B.