title: Force degradation of orthodontic latex elastics: An in-vivo study.
abstract: BACKGROUND
  Our objectives were to assess the force degradation of orthodontic latex elastics over 48 hours in vivo and to study the relationship between the amount of mouth opening and the degree of force decay.
  
  
  METHODS
  Fifty-two orthodontic patients wearing fixed appliances using Class II elastics were asked to wear premeasured-force 3/16-in heavy and medium intermaxillary elastics. The force amounts were measured and compared at different time intervals.
  
  
  RESULTS
  Fifty percent of the force was lost after 3.9 hours for the medium elastics and after 4.9 hours for the heavy elastics. A continuous significant force drop in all elastics was seen at all time intervals (P <0.05, P <0.001). There was greater force loss in the heavy elastics compared with the medium elastics in vivo at all time intervals (P <0.001); the rates of force loss, however, were similar.
  
  
  CONCLUSIONS
  Fifty percent of force degradation occurred in the first 4 to 5 hours. Because of breakage and for oral hygiene purposes, orthodontic elastics should be changed daily; otherwise, elastics can be used for 48 hours. Force decay of the elastics was correlated to the lateral distance between the maxillary canine and the mandibular first molar in occlusion.
authors.affiliation: Department of Preventive Dentistry, Division of Orthodontics, Faculty of Dentistry, Jordan University of Science and Technology, Irbid, Jordan.
authors.forename: Sadeq M Adel
authors.initials: SM
authors.lastname: Qodcieh
authors.affiliation: Department of Preventive Dentistry, Division of Orthodontics, Faculty of Dentistry, Jordan University of Science and Technology, Irbid, Jordan. Electronic address: susank@just.edu.jo.
authors.forename: Susan N
authors.initials: SN
authors.lastname: Al-Khateeb
authors.affiliation: Department of Biotechnology and Genetic Engineering, Faculty of Science and Art, Jordan University of Science and Technology, Irbid, Jordan.
authors.forename: Ziad W
authors.initials: ZW
authors.lastname: Jaradat
authors.affiliation: Department of Preventive Dentistry, Division of Orthodontics, Faculty of Dentistry, Jordan University of Science and Technology, Irbid, Jordan.
authors.forename: Elham S J
authors.initials: ES
authors.lastname: Abu Alhaija
mesh_terms: D003764:Dental Materials / Q000737:chemistry*; D004548:Elasticity; D007840:Latex / Q000737:chemistry*; D008422:Materials Testing; D016382:Orthodontic Appliance Design; D009967:Orthodontic Appliances; D013314:Stress, Mechanical; D013997:Time Factors
chemical_list: D003764:Dental Materials; D007840:Latex