Computational 3D analysis of the root-filling sealer interzone – relationship between irregularities and root canal morphology

• Applicants: Professorin Dr. Kerstin Bitter; Dr. Stefan Zachow; Professor Dr. Paul Zaslansky
• Subject Area: Biomaterials ; Medical Informatics and Medical Bioinformatics ; Dentistry, Oral Surgery
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 396127899

Bacterial infection of root canals leads to inflammation of the surrounding jaw-bone tissues. A common therapy is root canal treatment (RCT) aimed at the complete removal of infected tissue followed by a tight and durable filling of the disinfected root canal. Such filling comprises a solid inert biomaterial cone (e.g. gutta-percha) and a sealer that forms a thin sheet-like but tight interzone between the gutta-percha and the exposed dentine. The quality of the sealer interzone which hardens in situ plays a crucial role for treatment success. However, the sealer layer is hardly assessable on radiographs, and little is known about the structural 3D characteristics of a “good enough” sealer interzone in RCT. A comprehensive quantitative 3D analysis of sealer interzones has, so far not been reported. Consequently, the role of the sealer interzone and its relation to RCT success or failure remain unclear. To assess the quality of a sealant-based RCT in relation to various influencing parameters, there is a need for comparable quantitative descriptors of sealer interzones. Within this project we focus on rigorous evaluation of sealer interzone micro-geometries with respect to root canal morphologies and possible correlations to RCT parameters. Our objectives are to quantify defects and irregularities in sealer interzones, using ex vivo created RCTs followed by high-resolution (HR) 3D imaging with lab-µCT and phase contrast enhanced µCT to acquire spatial density information at unprecedent detail. Temporal HR3D image data of root canal treated specimens after ageing and loading in combination with computational analysis of pores, cracks, and other changes that may develop over time, open new and exciting perspectives for understanding and predicting changes in clinically created sealer interzones. Our detailed quantitative analyses of sealer interzones will identify commonalities or differences in RCT results which we plan to classify in the context of root canal morphologies. A rigorous computational evaluation correlating types and occurrences of defects in sealer interzones with 3D geometries of root canals and topographies of exposed dentinal walls will yield objective criteria to quantify, compare, and statistically evaluate defects in sealer interzones. Our investigations are expected to contribute to a better understanding of challenges in RCT and help derive possible alternatives for improvements in combinations of materials and treatment techniques. Long-term perspectives of our research are (1) to increase the understanding of and the awareness for possible failures in sealant-based root canal treatments, (2) to better understand the dependencies of such failures to root canal morphologies, (3) to prepare a scientific foundation for the development of more suitable materials, instrumentation, as well as improved treatment protocols, and (4) to provide image- and knowledge-based decision support for root canal treatment in clinical practice.

• DFG Programme: Research Units
• Subproject of: FOR 2804: The Materials Science of Teeth in Function: Principles of Durable, Dynamic Dental Interphases
• International Connection: Netherlands
• Cooperation Partner: Professor Hagay Shemesh, Ph.D.