A comparison of resins for embedding teeth, with special emphasis on adaptation to enamel surface as evaluated by scanning electron microscopy

Objective: Eight commercially available resins, Epoxy Embedding Medium (“Epon”), Spurr, Epofix®, Epo-Kwick®, Epo-Thin®, Technovit® 9100 New, Unicryl™, and Vestopal W®, all intended for embedding specimens for microscopy, were tested and compared for binding and adaptation to the enamel surface of human third molar crowns that had been embedded in them. Design: After sectioning, grinding and acid etching, the specimens were observed in the SEM. The presence or absence of a gap between enamel and resin was recorded together with the width of the gap, when present. Results: A pilot study, where gaps were observed before and after etching, indicated that the etching did not widen the gap appreciably. The resins could be divided into three groups according to gap width: “Epon” and Spurr performed best with a mean gap width of only 0.6 μm. Vestopal W®, Epofix®, Epo-Kwick®, Epo-Thin®, and Technovit® 9100 New constituted a group of medium performance with mean gap widths of 2.3, 3.4, 3.8, 3.9 and 3.9 μm, respectively. Less satisfactory performance was observed for Unicryl™, with a mean gap width of 7.4 μm. Conclusions: It is concluded that “Epon” and Spurr should be chosen for high quality embedding of undecalcified teeth, while Epo-Kwick® is an acceptable alternative if a faster procedure is needed.