Abstract

Objectives: This study aimed to assess the mandibular and maxillary teeth inter-root distance using a Cone- Beam Computed Tomography (CBCT) image and determine the safe zone to insert mini-screws.

Methods: In this retrospective study, we included 100 subjects that were taken by CBCT in the Department of Orthodontics, School of Dentistry, Mongolian National University Medical Sciences (MNUMS) of Mongolia, from 2014-2021. We used CBCT images in the 100 subjects were obtained with using OnDemand3D software for linear measurements.

Results: The maxillary teeth inter-root distance was analyzed a total 100 (men 30, female 70) CBCT scans. There was no statistically significant difference between the genders. Maximum inter-root distance in maxilla were measured 7 mm above Cementoenamel Junction (CEJ) 1.89 mm between canine and I premolar teeth (p<0.05), 1.73 mm between I and II premolar (p>0.05), 1.79 mm between II premolar and I molar (p>0.05) and 1.59 mm between I and II molar (p<0.001), respectively. Maximum inter-root distance in mandible was measured 7 mm below CEJ, 2.51 mm between I and II premolar (p<0.001), 2.16 mm between II premolar and I molar (p<0.01) and 2.43 mm between I and II molar (p<0.01), respectively.

Conclusion: This suggests that the maxillary, mandibular molar teeth inter-root on the buccal side far from 7mm CEJ is considered to be the safest position to implant mini screws on cortical bone.