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Figure 1. Microscopic examination of the experimental adhesives Exp-Eth and Exp-Ac. (a) Non-demineralized, non-stained TEM of Exp-Ac revealing a multitude of entrapped droplets, particularly at the bottom of the adhesive layer (Ar). The droplets are round or oval, with various sizes. A distinctive oxygen-inhibition layer (O2-I) was present in the top of the adhesive layer. C = flowable composite; Hy = hybrid layer; Ud = unaffected dentin. (b) Demineralized stained TEM of the submicron hybrid layer formed by Exp-Eth. (c) Feg-SEM of a µTBS failure pattern of Exp-Ac that exhibited mixed adhesive failure (dentin side). Note the high distribution of droplets at the bottom of the adhesive layer, while no droplets are seen near the top. (d) LM image of a drop of uncured adhesive solution of Exp-Ac dispensed on a glass plate. This drop contains many droplets centrally, and is bordered by a droplet-free halo, which becomes wider with time. The time indication indicates the time elapsed after the adhesive was applied.
