title: The standardized-taper root canal preparation--Part 4. GT file technique in large root canals with large apical diameters.
abstract: OBJECTIVE
  To describe the GT file shaping steps required to create apical resistance in the presence of a wide root apex.
  
  
  CONCLUSIONS
  Canals are occasionally encountered with apices wider than 0.25 mm. These can be some of the most difficult to manage with conventional instruments, and overfills are common. Shaping such canals with GT files requires a paradigm shift of thinking, extending tapered files through the apex to create linear resistance in the apical few mm of the canal. GT standard and accessory files allow canals with apices up to around 0.7 mm to be prepared for tapered gutta percha cone-fit. Apices larger than this should be considered too large for further shaping, and repaired with MTA before filling.
  
  
  CONCLUSIONS
  Tapered apical preparations offer optimal resistance form for obturation. Tapered apical preparations can be prepared in most roots with wide apices by extending GT files and GT accessory files to or through the apex. Apices wider than 0.7 mm should be repaired with MTA prior to filling.
authors: Dental Education Laboratories, 1515 State Street, Suite 16, Santa Barbara, CA 93101, USA. info@endobuchanan.com
authors: L S
authors: LS
authors: Buchanan
mesh_terms: D017607:Aluminum Compounds / Q000627:therapeutic use; D017610:Calcium Compounds / Q000627:therapeutic use; D003786:Dental Pulp Cavity / Q000033:anatomy & histology*; D004338:Drug Combinations; D004867:Equipment Design; D006171:Gutta-Percha / Q000627:therapeutic use; D006801:Humans; D010087:Oxides / Q000627:therapeutic use; D012387:Root Canal Filling Materials / Q000627:therapeutic use; D018915:Root Canal Preparation / Q000295:instrumentation* / Q000379:methods; D017640:Silicates / Q000627:therapeutic use; D013499:Surface Properties; D019227:Tooth Apex / Q000033:anatomy & histology
chemical_list: D017607:Aluminum Compounds; D017610:Calcium Compounds; D004338:Drug Combinations; D010087:Oxides; D012387:Root Canal Filling Materials; D017640:Silicates; C086631:mineral trioxide aggregate; D006171:Gutta-Percha