Assessing the Amount of Interdental Bone in Posterior Areas of the Mandible for Placing Orthodontic Mini-Implants

The aim of this study was to assess the amount of interdental bone in posterior areas of the mandible for placing orthodontic mini-implants to provide and control anchorage in orthodontic treatment. The amount of interdental bone in areas between the second premolars and first molars, first and second molars on the right and left sides of the mandible were determined in fifty patients by RVG using periapical radiographs. The images were assessed using Cygnus Media Software to determine the mesio-distal width of the interdental bone, starting at the crest of the alveolar bone (2 mm below the CEJ) every one millimeter up to 12 mm from the CEJ. The actual amount of interdental bone and the effect of related factors were assessed using chi-square test at a 95% confidence interval. The minimum desired interdental bone width for placing mini-implants, 3 mm from the CEJ, between the second premolar and first molar and the first and second molars of the mandible on both sides were significantly different (p<0.01): 1.8 mm (31%) more apical in the area between the second premolar and the first molar. There was also a statistically significant difference between the areas under study on the right side (p<0.002), which was 2.2 mm (44%) more apical in the area of the second premolar and the first molar. The most secure site for placing orthodontic mini-implants in the mandible is between the first and second molars at the height of 5.8 mm from the CEJ.