Is the computed tomography exam important for planning mini-implant installation?

Mini-implants are devices used to provide absolute and temporary anchorage for tooth movement. Objectives: The present study was carried out to compare the use of periapical radiographs and computed tomography (CT) for planning mini-implants performed by orthodontists.

Five radiographs and five CT scans of premolars and molars regions. These were analyzed by ten Orthodontists. Initially (T1), the evaluators indicated the preferred location for the insertion of a mini-implant, as well as the diameter and length of the device, using only a periapical radiograph. After 30 days (T2), the same evaluation was performed. Sixty days later (T3), the orthodontists reassessed the radiographs in association with the CT scans. Finally, after 90 days (T4), the evaluation was performed with the same exams. The comparison of the chosen diameter and length of the mini-implants was performed using the Student's t-test. The evaluation of the chosen insertion sites was analyzed by the Wilcoxon test. For both tests, the level of significance was 5%. The kappa concordance test was also performed for the intra- and inter-examiner evaluations.

The results of the study showed substantial or perfect intra-examiner and reasonable to perfect inter-examiner agreement. Considering the length and diameter of the mini-implants, no statistical difference was found between the groups. Regarding the insertion site, more than 20% of the treatment plans were changed when the CT scan was associated.

The results showed that the association of a CT scan with radiography frequently leads the professional to change the insertion point for the installation of mini-implants. Key words:Orthodontic anchorage procedures. Mini Dental Implants. Bone Screws. Cone-beam computed tomography. Periapical radiography.