title: The Effects of In-Office Reconditioning on the Slot Dimensions and Static Frictional Resistance of Stainless Steel Brackets.
abstract: BACKGROUND
  Orthodontists are commonly faced with the decision of what to do with loose brackets, and with inaccurately located brackets that need repositioning during treatment. One solution is to recycle the brackets. The potential effects of reconditioning a bracket are dependent upon many factors which may result in physical changes like alteration in slot tolerance, which may influence sliding mechanics by affecting frictional resistance.
  
  
  OBJECTIVE
  To study and compare the dimensional changes in the bracket slot width and depth in reconditioned brackets from unused brackets under scanning electronic microscope and to study and compare any consequent effects on the static frictional resistance of stainless steel brackets after reconditioning and in unused brackets.
  
  
  METHODS
  Dentarum manufactured 90 stainless steel central incisors edgewise brackets of size 0.22 X 0.030″ inch and 0° tip and 0°angulation were taken. 60 samples for measuring frictional resistance and 30 samples for measuring slot dimensions. Ortho organizers manufactured stainless steel arch wires 0.019 X 0.025″ straight lengths 60 in number were considered for measuring static frictional resistance.
  
  
  RESULTS
  The mean slot width and depth of new brackets were 0.0251″ and 0.0471″, which exceeded the manufacturers reported nominal size of 0.022″ X 0.030″, by 0.003″ and 0.017″. The reconditioned brackets demonstrated a further increase in mean slot width and depth to 0.028″ and 0.0518″ that is by 0.0035″ and 0.0047″ which is statistically significant (p=0.001, 0.002). The mean static frictional forces of the reconditioned brackets was nearly similar to that of new brackets that is 0.3167N for reconditioned brackets and 0.2613 N for new brackets.
  
  
  CONCLUSIONS
  Although the reconditioning process results in physical changes to bracket structure this does not appear to result in significant effect on ex-vivo static frictional resistance.
authors.affiliation: Senior Lecturer, Department of Orthodontics and Dentofacial Orthopedics, Narayana Dental College and Hospital , Chinthareddypalem, Nellore, Andhra Pradesh, India .
authors.forename: Rohini
authors.initials: R
authors.lastname: Iluru
authors.affiliation: Senior Lecturer, Department of Orthodontics and Dentofacial Orthopedics, Narayana Dental College and Hospital , Chinthareddypalem, Nellore, Andhra Pradesh, India .
authors.forename: Chaitanya
authors.initials: C
authors.lastname: Nellore
authors.affiliation: Reader, Department of Orthodontics and Dentofacial Orthopedics, Narayana Dental College and Hospital , Chinthareddypalem, Nellore, Andhra Pradesh, India .
authors.forename: Praveen Kumar Reddy
authors.initials: PK
authors.lastname: Karnati
authors.affiliation: Professor and Head, Department of Orthodontics and Dentofacial Orthopedics, Al Badar Rural Dental College and Hospital , Gulbarga, Karnataka, India .
authors.forename: Ashok Kumar
authors.initials: AK
authors.lastname: Thalapaneni
authors.affiliation: Senior Lecturer, Department of Orthodontics and Dentofacial Orthopedics, St. Joseph Dental College and Hospital , Duggirala, Eluru, Andhra Pradesh, India .
authors.forename: Vijay Bhaskar
authors.initials: VB
authors.lastname: Myla
authors.affiliation: Senior Lecturer, Department of Orthodontics and Dentofacial Orthopedics, Narayana Dental College and Hospital , Chinthareddypalem, Nellore, Andhra Pradesh, India .
authors.forename: Konda
authors.initials: K
authors.lastname: Ramyasree
authors.affiliation: Professor and Head, Department of Orthodontics and Dentofacial Orthopedics, Narayana Dental College and Hospital , Chinthareddypalem, Nellore, Andhra Pradesh, India .
authors.forename: Mandava
authors.initials: M
authors.lastname: Prasad
keywords: Bracket dimensions; Recycling; Slot width; Sloth depth