Abstract
AIMS:To assess the effect of system type on the amount of space closure when equal force use on each system and to compare the amount of rotation and tipping generated by lingual and conventional brackets. Materials and Methods: A mandibular typodont system with Class I wax form and set of metal teeth were used in this study. After removing the second premolar bilaterally, each tooth of the anterior teeth and canines were bonded with two bracket systems , preadjusted Roth stainless steel 0.022x0.030 inch conventional (labial) brackets (CoBS group) and lingual brackets (LiBS group) except right first premolar were bonded with lingual bracket (LIBS group) and left first premolar were bonded with labial bracket (CoBS group). Bite plane extension bar (BPB) and canine extension bar (CB) were constructed bilaterally for the measurement of first premolars tipping and rotation. A 200gm. of force applied by close coil spring to retract the first premolars bilaterally . After immersion of the typodont in water bath with 50-550 C for 5 minutes, the rate of space closure , tipping and rotation of first premolars were measured. Results: A statistical analysis (independent-samples t-test) used in this study, there was a significant difference between the two system groups (CoBS group and LiBS group). The LiBS group had a significant higher amount of tooth movement, and higher degree of rotation. For the tipping, the CoBS group had the higher level of tipping with a non-significant difference with LiBS group. Conclusions: The outcomes of this study showed that the higher rate of space closure and rotation were associated with LiBS group, while there is a nonsignificant difference in the amount of tipping between the two groups. So, Lingual appliance was appeared to be very effective method for tooth sliding during fixed orthodontic treatment.
