title: An In-vitro Comparison of Force Loss of Orthodontic Non-Latex Elastics.
abstract: OBJECTIVE
  The amount and consistency of the applied forces to the tooth are important factors in tooth movements; therefore, the aim of this study was to compare the initial force and the force loss of three brands of elastics in 24 hours.
  
  
  METHODS
  In this in-vitro study sixty non-latex elastics (3/16 medium) from three companies (Forestadent, Dentaurum and Ortho Technology) were randomly selected. Two static tests were performed, the first in a dry environment to evaluate the initial force and the other performed in a wet environment (artificial saliva) to evaluate the force loss in 24 hours. The Universal testing machine measured the forces after stretching the elastics to three times the lumen diameter. Data were analyzed by repeated measures ANOVA, One-way ANOVA, Tukey-HSD, Paired samples test, and one sample test.
  
  
  RESULTS
  The difference between the brands was significant (p=0.002). Force loss was observed in all samples; 4-7.5% force loss occurred after one hour and 19-38% force loss occurred after 24 hours. The average initial force of Forestadent and Ortho Technology was significantly higher than marketed forces (p<0.001), but the initial force of Dentaurum elastics was similar to the marketed force.
  
  
  CONCLUSIONS
  The force loss over 24 hours time period was Forestadent>Dentaurum>Ortho-Technology. According to the initial force and force loss percentage it is suggested to replace the non-latex elastics several times a day.
authors.affiliation: Associate Professor, Torabinejad Dental Research Center, Department of Orthodontics, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Shiva
authors.initials: S
authors.lastname: Alavi
authors.affiliation: Private Practice of Orthodontics, Tehran, Iran.
authors.forename: Atusa Rahnama
authors.initials: AR
authors.lastname: Tabatabaie
authors.affiliation: Assistant Professor, Department of Orthodontics, School of Dentistry, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Hajizadeh
authors.affiliation: Postgraduate Student of Orthodontics, Department of Orthodontics, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Alireza Haerian
authors.initials: AH
authors.lastname: Ardekani
keywords: Dentistry; Latex; Orthodontic Appliances; Rubber