The extension of resin tags in etched dentin: a misinterpretation?

The morphological characteristics of the filament structure, universally recognized as resin tags, in samples prepared using a new SEM methodology, are analyzed .

Ten non-carious, human third molars were cut transversally to obtain 10 dentinal surfaces. They were filled using an adhesive restorative technique. Subsequently, the samples were cut lengthwise to be SEM observed, and then randomly divided into 6 main groups according to the preparation modality of the section surface: Group A: EDTA; Group B: H(3)PO(4); Group C1: H(3)PO(4)+NaOCl; Group C2 H(3)PO(4)+NaOCl+H(2)O(2); Group D1: HCl+NaOCl; Group D2: HCl+NaOCl+H(2)O(2).

The resin tags which originate from resin penetration and polymerization within the dentinal tubules are small conic-trunk shaped plugs that are a few microns long. The thinner extension of the resin tags is probably due to the persistence of the lamina limitans.

A new method of specimen preparation for SEM visualization is proposed in order to effectively evaluate the penetration capacity of the adhesive in the dentinal substratum. In addition to the use of strong acids and bases, an agent capable of degrading the glycosaminoglycans was employed to completely remove the dentinal organic component.