In vivo Effects of an Er:YAG laser, an Ultrasonic System, and SRP on the Biocompatibility of Periodontally Diseased Root Surfaces in Cultures of Human PDL Fibroblasts

Objectives: The aim of the present study was to investigate the in vivo effects of an Er:YAG laser, an ultrasonic system and SRP on the biocompatibility of periodontally diseased root surfaces in cultures of human periodontal ligament fibroblasts (PDL). Methods: Forty single rooted teeth, considered for extraction due to severe periodontal destruction, have been randomly assigned to the following treatment and control groups: (1) Er:YAG laser (160 mJ/pulse, 10 Hz)(ERL), or (2) Vector® ultrasonic system (VUS), or (3) scaling and root planing using hand instruments (SRP), or (4) untreated control (C). Immediately after instrumentation, all test and control teeth were extracted and root specimens (4 mm2) were prepared from all mesial and distal surfaces (n=80). Root specimens were incubated with human PDL fibroblast cultures. Adherent cells were stained with methylene blue and counted using a reflected light microscope and the cell density per mm2 was calculated. Additionally, the cell morphology was investigated using SEM (n=8 teeth). Results: Cell counts within each group yielded the following means and standard deviations: ERL, 111±27 cells/mm2; VUS, 75±25 cells/mm2; SRP, 41±17 cells/mm2; control, 25±11 cells/mm2. Application of the Wilcoxon test revealed significant differences in the number of attached cells between the test and control groups (p<0.001, p<0.001, p<0.01, respectively). All laser and ultrasonically treated specimens showed significantly higher numbers of cells/mm2 than the SRP group (p<0.001, respectively). The difference between the ERL and VUS group was statistically significant (p<0.001). Conclusions: Within the limits of the present study, it can be concluded that (i) ERL, VUS and SRP promote the attachment of PDL fibroblasts on previously diseased root surfaces, (ii) periodontally diseased root surfaces inhibit the adherence of PDL fibroblasts, and (iii) the surface structure of ERL and VUS instrumented roots seems to offer better conditions for the adherence of PDL fibroblasts than SRP.