Multiple periapical dysplasias analyzed by cone-beam-computer tomography and 99Tcm-Scintigraphy.

Periapical cemental dysplasia (PCD) is considered a non-neoplastic proliferation of fibrous tissues and cementum-like hard tissues, usually occurring in the periapical regions of teeth. PCD is characterized by the presence of vital pulp and is often accidentally discovered during a general radiographic survey. PCD may arise from the tissue of odontogenic origin or occur as a reactive process in the periapical tissue. Multilocular occurrences in both jaws are rare. However, we encountered a case of multiple PCDs by orthopantomography, which showed different degrees of maturation in the mandible and maxilla by osteodensitometric detection via cone-beam computed tomography (CB-CT) validated by Tc-99m bone-scintigraphy (BS). Biopsies confirmed the radiological results. CB-CT osteodensitometry allows for the categorization and assessment of different stages of PCD maturation from beginning to florid, detection of remittent osseous changes, and evaluation in the clinical follow-up. When using the local cortical bone as a reference value of 100%, periapical dysplasias show density values of 75% in the mandible and 80% in the maxilla. Early classification of PCD is possible with CB-CT osteodensitometry.

Design and characterisation of vitrimer-like elastomeric composites from HXNBR rubber.

The present study aims at the incorporation of vitrimer-like properties into elastomeric composites as a promising approach towards the sustainable production of rubber-based materials. In particular, hydrogenated carboxylated nitrile butadiene rubber (HXNBR), as a technically relevant high-performance rubber, is covalently cross-linked with epoxy group-functionalised calcium silicate (Esilicate) across its pending carboxylic acid moieties. Reaction with the reactive functions attached on the filler surface results in the formation of ß-hydroxyl ester linkages at the HXNBR-Esilicate interface, which undergo thermo-activated transesterifications in the presence of a suitable catalyst. Topology rearrangements in the composites are confirmed by stress relaxation measurements at elevated temperatures. Comparison with an unfilled reference network reveals that the extent of stress relaxation can be mostly maintained upon the addition of the reactive filler even at large quantities. The Esilicate serves as both cross-linker and reinforcing filler, leading to a significant enhancement of the mechanical properties.