Comparative analysis of low-abrasive powders on root surface roughness and substance loss: an ex vivo study

To comparatively evaluate the effects of four low-abrasive air-polishing powders (glycine, erythritol, trehalose, and sodium bicarbonate) on root surface roughness and substance loss in an ex vivo model.

210 specimens from 105 human teeth were randomly allocated to four treatment groups (n = 50); 10 additional specimens served for measurement error analysis. Air-polishing was performed using glycine (25 μm), erythritol (14 μm), trehalose (30 μm), or sodium bicarbonate (40 μm). Three-dimensional surface topography was assessed by laser scanning microscopy before and after treatment using ISO 25,178 roughness parameters. Data were analyzed using rank-based ANCOVA with tooth type and surface location as covariates.

Post-treatment average roughness differed significantly between groups (p < 0.001, η²p = 0.217). Glycine (8.23 [5.45; 14.13] µm) and erythritol (6.65 [4.61; 10.22] µm) produced significantly higher values than trehalose (4.38 [2.87; 5.42] µm) and sodium bicarbonate (3.82 [2.83; 5.79] µm). Erythritol generated the most pronounced increases in valley depth and peak height. All groups showed negative skewness trends. No significant differences in substance loss were detected.

Glycine and erythritol produced greater surface roughness than trehalose and sodium bicarbonate under the tested device configuration, while all powders demonstrated minimal substance loss, supporting their safety for subgingival application.

Glycine and erythritol produced greater surface topographical changes compared to trehalose and sodium bicarbonate, which may reflect more pronounced powder-surface interaction; whether this translates into superior debridement efficacy requires direct microbiological investigation. The comparable and minimal substance loss across all powders supports their safety for repeated subgingival application.