Safe Zones for Miniscrew Insertion among Nepalese Population: A cadaveric study

Abstract

Introduction: Anchorage plays very important role in executing orthodontic treatment planning and achieving ideal goal. With the use of mini-implant, the job of orthodontists to control anchorage has been easier. Several radiographic, cone beam CT and histopathological studies have been performed to assess the safe locations in the interradicular spaces for miniscrew placement, the so-called ‘‘safe zones.’ The aim of the study is to determine safe zones for miniscrew placement among Nepalese population.

Methods: Cross sections of adult cadaver jaws were analyzed in 16 mandibles and 16 maxillae after decalcification. Direct measurements were done both in mesio-distal and bucco-lingual directions with the use of digital vernier caliper at 2 mm, 5 mm, 8 mm and 11 mm cut levels from the cervical line in posterior regions of the jaws.

Results: Generally interradicular distance measured greater than 3mm at all levels except at 2mm where the measurement varied considerably in both jaws. All the bucco-lingual measurements in maxilla were above 7 mm except at 2 mm level where the measurements varied. The average bucco-lingual distance measured between 6.52 mm to 9.63 mm in mandible. Generally, all the dimensions measured increased upon moving apically and distally except at 11 mm level between first and second premolar region.

Conclusion: At the buccal aspect of the posterior region of both jaws, the optimal sites are between the second premolar and the first molar and between the first and second in agreement with most of the studies done earlier.