Relationship of bone and soft tissue thickness with age and gender for orthodontic mini-implant placement by CBCT

The aim of the present study was to measure the thicknesses of bone and soft issues in the midpalatal area at certain points for the placement of orthodontic mini-implants using CBCT and evaluate their relationships with age and gender. A total of 161 subjects were evaluated in the present study, consisting of males (31.9%) with a mean age of 41.46±13.88 years and females (60.9%) with a mean age of 38.47±11.66 years. In all the samples 20 points were evaluated. First, the incisive foramen was located. Then para-coronal cross-sections were prepared at 4-, 8-, 16- and 24-mm distances from the posterior wall of the incisive foramen; in addition, on each cross-section, the mid-sagittal and para-sagittal areas were determined at 3- and 6-mm intervals bilaterally (5 points on the whole). The soft tissue and bone thickness were measured at these points. The soft tissue thicknesses were significantly different at all the 20 sample points between males and females (P<0.05). In other words, at all the points the soft tissue thicknesses were significantly greater in males compared to females. In some areas there was a positive relationship between age and soft tissue thickness (P<0.01), i.e. the soft tissue thickness increased with age. In addition, in the majority of points the overall bone thickness was significantly higher in males compared to that in females; however, in the majority of points, no positive relationship was found between age and bone thickness.. Age was not a determining factor for bone thickness, while where was a stronger relationship between soft tissue thickness and age. In addition, the most appropriate locations for the placement of orthodontic mini-implants were paramedian area at 3- and 6-mm distances from the suture, 4 mm posterior to the incisive foramen.