Objective: To determine the change in the sagittal and vertical position of the mini-implant
placed in the maxilla during distal movement of the entire maxillary dentition. Materials and
Methods: Twenty eight mini-implants, fourteen on each side were evaluated in young healthy
patients in the age group of 15 years to 25 years. Distal movement of the entire maxillary arch
was performed with 1.2 mm x 8 mm stainless steel mini-implants on 0.018” x 0.025” stainless
steel wire. CBCT were taken at the start of (T1) and at the end of six months (T2) of distal
movement of the maxillary teeth. The vertical and sagittal angulation of the mini-implant was
measured at T1 and T2. The linear distance between the mini-implant and the alveolar crest, the
maxillary sinus, the maxillary second premolar and the maxillary first permanent molar were
measured. The change in angulation and the linear displacement of the mini-implant were
evaluated in the vertical and sagittal plane. Wilcoxon signed rank test was performed to
determine if there was a statistically significant change in the position of the mini-implant.
Results: Vertically, there was a significant change in the linear distance between the miniimplant
and the alveolar crest on the right side (p≤.006) and the mini-implant and the maxillary
sinus on the left side (p≤.003). Sagittally, there was a statistically significant rotation of the miniimplant
occlusally (left side p≤.004 and right side p≤.002). The head and tip of the mini-implant
were displaced towards the maxillary second premolar and away from the maxillary first
permanent molar respectively. There was a significant relative displacement of the mini-implant
anteriorly away from the maxillary first permanent molar (left side p≤.026 and right side
p≤.041)and closer to the maxillary second premolar (left side: p≤..011 and right side: p≤.002).
Conclusions: There was a statistically and clinically significant rotation of the mini-implant in
the vertical and sagittal direction during distal movement of the entire maxillary teeth. The
linear displacement of the mini-implant was more pronounced in the sagittal direction compared
to the vertical direction.
Schlagwörter: Keywords: mini-implant; distal movement; vertical, sagittal; displacement, cohort study