Effects of Adjunctive EDTA and Air-Polishing Powders on Periodontitis-Affected Root Surfaces: A SEM Study

Background: Mechanical subgingival instrumentation remains the gold standard in periodontitis treatment; however, it may leave residual debris and induce surface alterations. Adjunctive strategies such as air polishing and ethylenediaminetetraacetic acid (EDTA) might optimize root surface conditions. Objective: To evaluate, by scanning electron microscopy (SEM), the effects of scaling and root planing (SRP) combined with EDTA, with or without adjunctive erythritol- or glycine-based air polishing, on root surface alterations and smear layer formation. Materials and Methods: Ten extracted human teeth affected by periodontitis (yielding twenty samples) were included. Two teeth served as descriptive controls. The remaining teeth were allocated to four treatment groups. The first three groups included samples obtained from the middle portion of the roots: S (SRP + EDTA), Se (SRP + erythritol air polishing + EDTA), and Sg (SRP + glycine air polishing + EDTA). The fourth group, Js, consisted of samples from the cementoenamel junction (CEJ) treated with SRP + EDTA. SEM images were appreciated qualitatively and assessed using ordinal scores (0-3) for marks, cracks (×100), and smear layer (×1000). Non-parametric statistics were applied. Results: A significant difference in mark scores was found among S, Se, and Sg samples (H = 13.411, p = 0.001), with Se samples showing lower mark scores than S (p = 0.001). Crack scores also differed among groups (H = 12.038, p = 0.002), with higher values observed in Se compared to S (p = 0.001). Smear layer scores did not differ among groups (H = 0.102, p = 0.950). Compared with S samples, Js differed only in marks (p = 0.009), with no significant differences in cracks or smear layer. Conclusions: Within the limitations of this in vitro study, root surface alterations and smear layer formation showed variable responses across treatment protocols, with comparable smear layer scores. Similar effects were observed for CEJ and mid-root samples; however, these findings should be interpreted with caution. Further studies are needed to clarify the potential clinical relevance of these observations.