Evaluation of mini-implant sites in the posterior maxilla using traditional radiographs and cone-beam computed tomography

Abstract

Objectives:To evaluate the accuracy of using routine 2-dimensional (2D) radiographs (panoramic and periapical) when evaluating the position of orthodontic temporary anchorage devices (mini-implants) in the maxilla, and to compare the results to 3-dimensional cone-beam computed tomography (CBCT).Methods:This cross-sectional study was conducted at King Abdulaziz University, Faculty of Dentistry, Jeddah, Kingdom of Saudi Arabia from February 2014 to January 2015. Panoramic and periapical radiographs were used to examine the position of mini-implants in relation to the adjacent roots. Rating of mini-implants position was performed by 82 dentists from different specialties, using 2 D images according to the following criteria: 1) away from the root; 2) mini-implant tip appears touching the lamina dura; and 3) mini-implant overlays the lamina dura. The results were compared with CBCT findings.Results:There was no difference between dentists from different specialties when rating the position of the mini-implants (Cronbach’s alpha=0.956). The accuracy of the periapical images was 45.1%, while the panoramic images 33.6%. However, both panoramic and periapical radiographs were significantly inaccurate when assessing the mini-implant position when compared with the CBCT findings (p=0.0001).Conclusion:Three-dimensional CBCT technology allows better visualization of mini-implant placement. The use of CBCT when assessing the position of mini-implants is recommended.

Distortion of digital panoramic radiographs used for implant site assessment

“…Although the radiation exposure of standard digital panoramic radiography was found to be much less compared to CBCT, some cases require CBCT scan for more accurate measurements. [14] It is the clinician's responsibility to determine the need for a more extensive radiographic study for the best outcome with the least possible risk.…”

“…Bone width can be determined clinically using bone-mapping techniques or by cone-beam computerized tomography (CBCT) scan which has been shown to be more accurate than panoramic radiographs. [14] Hence, careful radiographic and clinical measurements are essential to determine the size of the implant for the intended site.…”

Additional intraoral radiographs may change the judgment regarding the final position of orthodontic mini-implants

“…Accuracy of PAR for determining the final position of OMI is lower when compared with CBCT. 17 , 19 The present study did not aim to test accuracy, however, results showed great variability suggesting low reliability of these radiographic methods (PAR, VBW and OC) for this type of evaluation. In general, it was clear that additional radiographs might influence the interpretation of the OMI final position, however, a definite pattern showing which exam modality overestimates or underestimates distances was not observed.…”

“…Correct positioning of orthodontic mini-implants (OMI) is one of the most important factors associated to their success rate. 1 - 5 Several methods 6 - 17 have been used to assess the position of these devices. Periapical radiograph (PAR) is the most used imaging modality for post-placement evaluation of OMI position, 18 despite its limitations and the lack of studies to actually support this recommendation.…”

“… 16 In fact, significant differences between PAR and CBCT have been found regarding the assessment of the proximity of the OMI and roots, with less than 50% agreement between these imaging modalities. 17 , 19 However, although CBCT seems to be the most indicated method for this assessment, 4 , 5 , 20 higher radiation dose and cost are still disadvantages that preclude their routine use. This justifies the search for other radiographic methods with the potential to assist or complement the assessment of OMI final position when necessary.…”