title: Bracket placement in lingual vs labial systems and direct vs indirect bonding.
abstract: OBJECTIVE
  To examine the ultimate accuracy of bracket placement in labial vs lingual systems and in direct vs indirect bonding techniques.
  
  
  METHODS
  Forty pretreatment dental casts of 20 subjects were selected. For each dental cast, four types of bracket placement were compared: labial direct (LbD), labial indirect (LbI), lingual direct (LgD), and lingual indirect (LgI). Direct bonding was performed with the casts held in a mannequin head. Labial brackets were oriented with a Boone gauge, and lingual brackets were oriented with the Lingual-Bracket-Jig System. Torque error (TqE) and rotation deviation (RotD) were measured with a torque geometric triangle and a toolmaker's microscope, respectively. Both torque and rotational measurements were evaluated statistically as algebraic and absolute numeric values, using analysis of variance with repeated measures.
  
  
  RESULTS
  Absolute TqE and RotD were significantly (P < .001) higher in direct than in indirect bonding techniques higher in both the labial and lingual bracket systems by twofold and threefold, respectively (LbD = 7.26 degrees , 1.06 mm; vs LbI = 3.02 degrees , 0.75 mm; LgD = 8.42 degrees , 1.13 mm; vs LgI = 3.18 degrees , 0.55 mm). No statistically significant difference was found between labial and lingual systems for the same bonding technique. Maxillary incisors demonstrated the largest RotD angle (eg, right lateral: 12.04 degrees ). A distal off-center RotD was predominant in the mandibular dentition.
  
  
  CONCLUSIONS
  Labial and lingual systems have the same level of inaccuracy. For both systems, indirect bonding significantly reduces absolute TqE and RotD. The TqE found can cause transverse discrepancy (scissors or crossbite) combined with disclusion with antagonist teeth. The RotD found can result in irregular interproximal contact points.
authors.affiliation: Department of Orthodontics, The Maurice and Gabriela Goldschleger School of Dental Medicine, Tel Aviv University, Tel Aviv, Israel. nshpack@post.tau.ac.il
authors.forename: Nir
authors.initials: N
authors.lastname: Shpack
authors.forename: Silvia
authors.initials: S
authors.lastname: Geron
authors.forename: Ioannis
authors.initials: I
authors.lastname: Floris
authors.forename: Moshe
authors.initials: M
authors.lastname: Davidovitch
authors.forename: Tamar
authors.initials: T
authors.lastname: Brosh
authors.forename: Alexander Dan
authors.initials: AD
authors.lastname: Vardimon
mesh_terms: D001840:Dental Bonding / Q000379:methods*; D006801:Humans; D003765:Models, Dental; D016910:Orthodontic Brackets; D009971:Orthodontics, Corrective / Q000295:instrumentation*; D012399:Rotation; D019415:Torque