title: Comparison of canine retraction by in vivo method using four brands of elastomeric power chain.
abstract: OBJECTIVE
  To investigate the amount of space closure by movement of canines into the extraction spaces using four brands of elastomeric power chains (EPCs) by intraoral application with pre-adjusted appliance for 6 weeks.
  
  
  METHODS
  The sample size calculation was based on the studies of Boester and Johnston and also with repeated measures analysis of variance (ANOVA) continuous data for force degradation, standard deviation of 24.9 g, and also from a pilot study, which totaled to around 17 patients with a mean age of 20 ± 2 years and receiving fixed orthodontic treatment that required retraction of canines into the premolar extraction spaces in all four dental arch quadrants. Four brands of EPCs, namely the Ormco, 3M Unitek, Rocky Mountain, and Highland, which were closed-link with five loops delivering less than or equal to 250 g were used. The rates of canine retraction were measured between the attachment points on the canine bracket hook and first molar hook using a Mitutoyo Digital Vernier Caliper at the time of first application, after 3 weeks of use, and at the end of 6 weeks of use, and were subjected to statistical calculations.
  
  
  RESULTS
  The distances recorded from canine retraction were similar with slight differences noticed in the four brands of EPCs. However, no statistically significant difference was observed in relation to the EPCs.
  
  
  CONCLUSIONS
  Although all brands of the EPCs produced space closure of canines, it was observed that not much of a significant difference existed among the products tested.
authors.affiliation: Department of Orthodontics and Dentofacial Orthopaedics, Drs. Sudha and Nageswara Rao Siddhartha Institute of Dental Sciences, Chinaoutpally, Gannavaram, Andhra Pradesh, India.
authors.forename: Ravi Krishna
authors.initials: RK
authors.lastname: Kanuru
authors.affiliation: Department of Oral Surgery, School of Dentistry, Zawia University, Zawia, Libya.
authors.forename: Mustafa
authors.initials: M
authors.lastname: Azaneen
authors.affiliation: Department of Orthodontics and Dentofacial Orthopaedics, KLR Lenora Institute of Dental Sciences, Rajahmundry, India.
authors.forename: Veera
authors.initials: V
authors.lastname: Narayana
authors.affiliation: Government Dental College and Hospital, Gunadala, Vijayawada, Andhra Pradesh, India.
authors.forename: Balaram
authors.initials: B
authors.lastname: Kolasani
authors.affiliation: Department of Orthodontics and Dentofacial Orthopaedics, Saraswathi Dhanwantari Dental College, Parbhani, Maharashtra, India.
authors.forename: Ravikishore Reddy
authors.initials: RR
authors.lastname: Indukuri
authors.affiliation: Department of Orthodontics and Dentofacial Orthopaedics, RAMA Dental College, Kanpur, Uttar Pradesh, India.
authors.forename: P Firoz
authors.initials: PF
authors.lastname: Babu
keywords: Canine retraction; elstomeric power chain; premolar extraction