title: Occlusal loading of EBA and MTA root-end fillings in a computer-controlled masticator: a scanning electron microscopic study.
abstract: OBJECTIVE
  The aim of this investigation was to assess the marginal adaptation of Super-EBA (EBA) and Pro Root MTA (MTA) root-end fillings and the occurrence of microcracks in resected root-ends of extracted teeth before and after occlusal loading for a five-year equivalent period in a computer-controlled masticator.
  
  
  METHODS
  Twenty-four molar teeth were root-filled using lateral condensation and their root-ends resected. Root-end cavities were prepared and either EBA or MTA root-end fillings were placed. All surgical procedures were completed in vitro under an operating microscope. Replicas taken of the root-end fillings and resected root-ends were examined using an SEM before and after they were subjected to in vitro chewing cycles in a computer-controlled chewing simulator for the equivalent of 5 years. Marginal adaptation and integrity of the two root-end filling materials were evaluated and the presence of microcracks recorded.
  
  
  RESULTS
  Before loading, a continuous margin was observed with 99.4 +/- 2.4% of EBA and 99.2 +/- 1.6% of MTA root-end fillings. After loading, the percentage of continuous margin decreased to 93.1 +/- 6.6% and 98.9 +/- 3.2% for EBA and MTA, respectively. After occlusal loading, 39.5% of the EBA root-end fillings were overfilled, whilst 52.6% of the MTA root-end fillings were underfilled. In total, 12.5% of the resected root-end surfaces showed microcracking before loading and 25% after occlusal loading.
  
  
  CONCLUSIONS
  Both EBA and MTA displayed excellent marginal adaptation before masticatory loading. After loading, the amount of continuous margin for both root-end filling materials decreased slightly but was still high.
authors.affiliation: Endodontic Division, Department of Preventive Dentistry, Cariology and Periodontology, University of Zurich, Switzerland. c.peters@zzmk.unizh.ch
authors.forename: C I
authors.initials: CI
authors.lastname: Peters
authors.forename: O A
authors.initials: OA
authors.lastname: Peters
mesh_terms: D017607:Aluminum Compounds / Q000737:chemistry*; D000704:Analysis of Variance; D001732:Bite Force; D017610:Calcium Compounds / Q000737:chemistry*; D003198:Computer Simulation; D018772:Dental Marginal Adaptation; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D004338:Drug Combinations; D006801:Humans; D008409:Mastication; D008855:Microscopy, Electron, Scanning; D008954:Models, Biological; D008963:Molar; D010087:Oxides / Q000737:chemistry*; D016628:Replica Techniques; D012184:Retrograde Obturation / Q000295:instrumentation; D012387:Root Canal Filling Materials / Q000737:chemistry*; D017640:Silicates / Q000737:chemistry*; D013499:Surface Properties; D014464:Ultrasonic Therapy / Q000295:instrumentation
chemical_list: D017607:Aluminum Compounds; D017610:Calcium Compounds; D017220:Dentin-Bonding Agents; D004338:Drug Combinations; D010087:Oxides; D012387:Root Canal Filling Materials; D017640:Silicates; C086631:mineral trioxide aggregate; C084074:Super EBA