Cleaning potential of glycine air-flow application in an in vitro peri-implantitis model

The study aimed to assess the accessibility of a glycine powder blasting device to implant surfaces in models imitating different peri-implantitis defects. The null hypothesis was that the device allows for complete surface decontamination in all defect types.

Eighteen implants were dip-coated and placed in resin blocks with different defect morphologies. Vertical bone angulations of 90°, 60°, 30° and 15° were chosen and the implants were treated for 10 s using an air-flow device employing glycine powder. Once removed, photographs from the implants were taken in three directions: perpendicularly (90°) to the implant axis and with an angulation of 60° and 120°, the latter ones to assess the coronal and apical thread areas. The area with residual color represented areas, which were not accessible to the powder. This area was planimetrically assessed. Medians and inter-quartile ranges (IQR) of the percentage of uncleaned surfaces were calculated and nonparametric paired and unpaired statistical analyses were performed.

The median percentages (IQR in brackets) of uncleaned areas in the 90°, 60°, 30° and 15° defects were of 3%(A) (6), 8%(A) (4), 24%(B) (8), and 51%(C) (13), respectively (different superscript capital letters represent statistically significant differences; P < 0.0001). The upper aspects of the threads (coronal faces) were significantly better cleaned than the lower ones (P < 0.001). This finding was more pronounced in narrower defects.

Although a complete surface decontamination could not be performed in any of the defects, the biggest part of the surface could be cleaned in the larger defects. Especially in narrow defects and under the threads, residually stained areas remain on the implant surfaces.