FERREIRA, D. P. Comparative study of the anterior-posterior position of the
lower first molars in the orthodontic treatment, using Straight-Wire and
Edgewise techniques, in
cases with Angle Class I
malocclusion, with
extraction of first premolars. Mastering dissertation in Odontology, concentrating
field of Orthodontics, of Metodista University of São Paulo, 2005.
This study evaluated the anterior-posterior position of the lower first molars,
during the orthodontic treatment, using a lingual arch as an anchorage accessory in
the Straight-Wire technique, in comparison to the cases treated by the Edgewise
technique, without the use of a lingual arch. Two groups were selected, both
presenting with Angle 7 Class I malocclusion, treated with the extraction of upper and
lower first premolars. The sample consisted of 255 lateral cephalometric x-rays
obtained from Brazilian patients. The patients were of both genders, with an average
age between 13 years and 6 months and with different standards of facial growth.
Based in the analysis and discussion of the results, it was concluded that: 1) from the
start of treatment to the end of leveling phase, the lost of anchorage by mesial crown
tipping of lower first molar was greater in the cases treated with Straight-Wire
technique; 2) from the end of leveling phase to the end of treatment, the lost of
anchorage by bodily movement of the lower first molar was greater in the Edgewise
technique; 3) from start to end of treatment the total anchorage loss was greate r in
the patients treated with Edgewise technique; e 4) the anterior-posterior movement
of the lower incisors did not shown any statistically significant difference for both
techniques, in all phases of treatment.

ABSTRACT - Universidade Metodista de São Paulo