title: Fracture resistance of immature teeth filled with mineral trioxide aggregate or calcium-enriched mixture cement: An ex vivo study.
abstract: BACKGROUND
  The ability of mineral trioxide aggregate (MTA) to strengthen the tooth structure has been studied with contradictory results, and there is a lack of data in the case of Calcium-enriched mixture (CEM) cement as a novel endodontic biomaterial. The aim of the present study was to evaluate the reinforcing effect of MTA and CEM cement on simulated immature teeth.
  
  
  METHODS
  This ex vivo study was carried out on a total of 46 human maxillary incisors. Access cavities were prepared. Five teeth were randomly selected as negative control. The root length of the remaining teeth was standardized to 9 mm. Rotary files and peeso reamers were used to enlarge the canals. The prepared specimens were randomly assigned into three experimental (n = 12) and a positive control (n = 5) groups. In groups 1 and 2, the canals were filled with MTA or CEM cement, respectively. In group 3, a 5-mm MTA plug was placed, and the remainder of the canal was filled with composite resin. The canals of the positive control were kept unfilled. After 6 months, the teeth were tested for fracture strength in a universal testing machine. The groups were compared using Univariate analysis of variance (ANOVA).
  
  
  RESULTS
  There were significant differences between fracture strength of experimental groups with that of both control groups (P<0.05). However, the differences among the three experimental groups were not statistically significant (P>0.05).
  
  
  CONCLUSIONS
  After 6 months, MTA and CEM cement exhibit distinct reinforcing effect on immature teeth.
authors.affiliation: Dental and Periodontal Disease Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
authors.forename: Amin Salem
authors.initials: AS
authors.lastname: Milani
authors.forename: Saeed
authors.initials: S
authors.lastname: Rahimi
authors.forename: Zahra
authors.initials: Z
authors.lastname: Borna
authors.forename: Mohammad Asghari
authors.initials: MA
authors.lastname: Jafarabadi
authors.forename: Mahmoud
authors.initials: M
authors.lastname: Bahari
authors.forename: Alireza Sighari
authors.initials: AS
authors.lastname: Deljavan
keywords: Calcium-enriched mixture cement; fracture resistance; fracture strength; immature teeth; mineral trioxide aggregate