Microcomputed Tomography-Based Assessment of Retrieved Dental Implants

Purpose: The aim of this study was to demonstrate the potential of microcomputed tomography (micro- CT) technology in the assessment of retrieved dental implants. Cases are presented to illustrate the value of micro-CT imaging techniques in determining possible mechanical causes for dental implant failures. Materials and Methods: Eight retrieved dental implants were randomly selected from a pool and imaged using a micro-CT device. Source voltages (80 to 100 kV) and source-to-detector distances (65 to 70 mm) were based on signal quality requirements with an additional criterion of achieving the highest resolution with the sample entirely in the field of view in the projection plane. One additional sample was chosen for histology and tomographic imaging so that the information contained therein could be compared. Results: The micro-CT images displayed high contrast between the implant, bone, and background, with negligible metal artifacts. The micro-CT technology used in this study delivered excellent images of the retrieved implants. As a result of the quality and resolution (pixel size: 5.52 to 6.15 μm) of the images, surface morphology as well as internal structures of the retrieved implants could be observed in great detail. The majority of the retrieved implants had increased wear, dents, pits, regular shallow scratches, and deep scratches in the implant-toabutment engagement area. Furthermore, plastic deformations, microcracks, and brittle implant fractures were observed in two implants. Conclusion: The mechanical competence of dental implant components plays a major role in the success of implant treatment. When failures do occur, a nondestructive three-dimensional assessment of such failed implants and their components is helpful in understanding the underlying factors. Micro-CT was found to be a useful tool for the morphologic assessment of retrieved dental implants. Keywords: dental implants, mechanical damage, microcomputed tomography, nondestructive imaging, retrieved implants