Standardization of Three-Dimensional Pose of Cylindrical Implants From Intraoral Radiographs

Abstract

BackgroundTo introduce a theoretical solution to a posteriori describe the pose of a cylindrical dental fixture as appearing on radiographs; to experimentally validate the method described.MethodsThe pose of a conventional dental implant was described by a triplet of angles (phi-pitch, theta-roll, and psi-yaw) which was calculated throughout vector analysis. Radiographic- and simulated-image obtained with an algorithm were compared to test effectiveness, reproducibility, and accuracy of the method. The length of the dental implant as appearing on the simulated image was calculated by the trigonometric function and then compared with real length as it appeared on a two-dimensional radiograph. ResultsTwenty radiographs were analyzed for the present in silico and retrospective study. Among 40 fittings, 37 resulted as resolved with residuals ≤1mm. Similar results were obtained for radiographic and simulated implants with absolute errors of -1.1±3.9° for phi; -0.9±4.1° for theta; 0±1.1° for psi. The real and simulated length of the implants appeared to be heavily correlated. Linear dependence was verified by the results of the robust linear regression: 0.9757 (slope), +0.1344mm (intercept), and an adjusted coefficient of determination of 0.9054.ConclusionsThe method allowed clinicians to calculate, a posteriori, a single real triplet of angles (phi,theta,psi) by analyzing a two-dimensional radiograph and to identify cases where standardization of repeated intraoral radiographies was not achieved. The a posteriori standardization of two-dimensional radiographs could allowed the clinicians to minimize the patient's exposure to ionizing radiations for the measurement of marginal bone levels around dental implants.Trial registrationThe Human Investigation Committee (IRB) of University of Pisa approved present retrospective data analysis (Ethical Approval Form 2626/2008 Protocol Number 58183)