Introducing a Novel Analysis Technique for Osseointegrated Dental Implants Retrieved 29 Years Postsurgery

Purpose: To investigate osseointegration of oral implants, which were retrieved from a patient after 29 years in situ, we use novel three‐dimensional analysis methods and visualization techniques that supplement conventional two‐dimensional analysis. Materials and Methods: The sample processing involved nondecalcification and embedment in resin. Conventional two‐dimensional histomorphometrical methods were conducted. Additionally, the quantification was extended to three‐dimensional by using synchrotron radiation micro‐computed tomography (SRµCT) technique and two relevant visualization methods for the three‐dimensional data were introduced. Results: The three‐dimensional results involved three‐dimensional quantification and visualization of two implant samples with methods beyond state‐of‐the‐art. Traditional two‐dimensional histomorphometrical results revealed a mean bone‐implant contact (BIC) of about 50%. In most samples, bone area (BA) was lower inside the treads compared with out‐folded mirror images, which were confirmed by the three‐dimensional quantification. The BIC along four selected regions showed highest percentages in the bottom/valley region and lowest in the thread‐peak region. Qualitative observations revealed ongoing bone remodeling areas in all samples. The apical hole demonstrated high osseointegration. Conclusion: The novel techniques including an animation and an out‐folding of BIC and BA enabled a simultaneous visualization of the three‐dimensional material obtained from SRµCT data. However, the two‐dimensional histological sections were needed for qualitative and quantitative evaluation of osseointegration and, thus, both methods are considered equally important.