title: An indigenously designed apparatus for measuring orthodontic force.
abstract: OBJECTIVE
  An indigenous apparatus is designed to measure the orthodontic force delivered from elastomeric chains and compare this force with values obtained from the Instron universal testing machine.
  
  
  METHODS
  An indigenously designed apparatus is developed to evaluate forces delivered by various orthodontic auxiliaries. The apparatus consists of a flat steel platform, movable arm, and a mounted screw gauge arm. Orthodontic brackets can be attached to these arms. An electric circuit is connected, to the movable arm, which will estimate the forces exerted between brackets with elastomeric chain. The circuit is connected to the signal conditioner which will display the reading. Elastomeric chain with four links is attached to the arms. The movable arm is adjusted to create orthodontic forces and calibrated on the digital displayer. Twenty Elastomeric chains are used and forces are calibrated with the indigenously designed apparatus. The values of the force is compared with the forces calibrated with Instron universal testing machine to compare the efficacy of the indigenous apparatus.
  
  
  RESULTS
  The force values obtained from activation of elastomeric chain segments, in the Instron universal testing machine and the indigenous apparatus were in the range of 100 to 150 grams, initially at 1mm activation then, took a steep rise to 300 to 350 grams at 5mm activation and then, had a gradual increase for the remaining 5mm activation, reaching 400 to 450 grams.
  
  
  CONCLUSIONS
  The Indigenous apparatus can be considered efficient in measuring tensile force generated by orthodontic auxiliaries.
authors.affiliation: Senior Lecturer, Department of Orthodontics, Saveetha Dental College , Velappanchavadi. Chennai-77, India .
authors.forename: S P Saravana
authors.initials: SP
authors.lastname: Dinesh
authors.affiliation: Professor, Department of Orthodontics, Saveetha Dental College , Velappanchavadi. Chennai-77, India .
authors.forename: A V
authors.initials: AV
authors.lastname: Arun
authors.affiliation: Professor, Department of Orthodontics, Saveetha Dental College , Velappanchavadi. Chennai-77, India .
authors.forename: K K Shantha
authors.initials: KK
authors.lastname: Sundari
authors.affiliation: Professor, Department of Orthodontics, Saveetha Dental College , Velappanchavadi. Chennai-77, India .
authors.forename: Christine
authors.initials: C
authors.lastname: Samantha
authors.affiliation: Professor, Department of Orthodontics, Saveetha Dental College , Velappanchavadi. Chennai-77, India .
authors.forename: K
authors.initials: K
authors.lastname: Ambika
keywords: Elastomeric chain; Instron universal testing machine; Orthodontic force