Informed choices for challenging specimens when choosing methacrylate resin systems for histology.

Functional restoration for orthopedic, systemic, or dental purposes uses a diverse range of biomaterials. Monitoring for any subsequent failures associated with pathology is vital. To this end, an alternative methodology beyond that of cutting sections by conventional microtome knife-based histomethodologies was pioneered. The method was to saw a block of tissue followed by grinding the unsupported slice to the required thickness. The sawing and grinding of unsupported bones or teeth exposed not only the specimen fragility, but also the delicacy of the associated soft tissues. Although incomplete, the significance of the technique was recognized and improvements were incorporated which persist to the present day addressing the histopathology of challenging specimens. One major improvement for preserving cellular structure as well as reducing fracture incidence was achieved by impregnating tissue samples with cross-linked resins prior to the cutting and grinding processes. Methyl and glycol methacrylate resins superseded all other choices because of the advantages of photo-initiated curing. Further pioneering work led to the formulation of increasingly appropriate resin systems and the subsequent processing protocols evolved, as clinical needs for histology-specific techniques became apparent. Over the decades, several key pioneers entered this scientific arena to develop the now established resin formulation, processing protocols, and allied applications. This has led to the commercialization of the various resin systems. The aim here is to discuss the commercially available glycol and methyl methacrylate resin systems and their practical application to a variety of important techniques used in the histological assessment of complex pathology specimens.