Photoinactivation of F. nucleatum and P. gingivalis using the ruthenium-based RD3 sensitizer and a conventional halogen lamp.

OBJECTIVE: The photodynamic therapy (PDT) is an alternative method to suppress oral pathogens by the activation of a photosensitizer with laser light. The aim of this study was to investigate the phototoxic effect of three ruthenium-based photosensitizers on Fusobacterium nucleatum and Porphyromonas gingivalis. METHODS: In this in vitro study F. nucleatum and P. gingivalis were incubated with three photosensitizers: (i) a hydrophobic tris-(4,7-diphenyl-1,10-phenanthroline)-ruthenium(II)-dication (RD3), (ii) a hydrophilic tris-[(1,10-phenanthroline-4,7-diyl)-bis-(benzenesulfonato)]-ruthenate tetra-anion (RSD3) and (iii) a lower hydrophilic tris-(2,2'-bipyridine)-ruthenium(II) dication (RBY). The subsequent irradiation was done with blue-band halogen light (450-485nm) for 20s using a conventional polymerizer. Control samples consisted of bacterial cell suspension irradiated and non-irradiated in the absence of photosensitizer or incubated with the photosensitizer without irradiation. Bacterial inactivation was determined by the numbers of colony-forming units (cfu/ml) after anaerobic cultivation. RESULTS: The RD3 photosensitizer reduced the viability of F. nucleatum by 4-log10 and of P. gingivalis completely after irradiation for 20s. The viability loss correlated significantly with the concentration of the RD3 photosensitizer and reached a peak at a concentration of 12.5µM (p<0.05). The RSD3 and RBY photosensitizers had distinctly lower phototoxic effects in comparison to RD3. CONCLUSION: The RD3 photosensitizer showed a phototoxic effect on F. nucleatum and P. gingivalis. The results suggest that the application of the RD3 photosensitizer under visible light may be helpful as an adjunct treatment approach to the inactivation of periodontopathogenic bacteria.

Evidence for a specific crevicular lymphocyte profile in aggressive periodontitis.

BACKGROUND AND OBJECTIVE: It is undisputed that the periodontal pocket is a particular region of the host defense that is dominated by polymorphonuclear leukocytes. However, little is known about the lymphocytes in the crevice. It was the aim of this study to analyse the proportions of T cells (CD3+), T-helper cells (CD4+), T-suppressor cells (CD8+), and B cells (CD20+) in the crevice of patients with localized aggressive periodontitis (LAP), generalized aggressive periodontitis (GAP), and generalized chronic periodontitis (CP). The results were compared with those obtained from periodontally healthy controls. MATERIAL AND METHODS: Crevicular cells were collected according to a previously described method. The lymphocyte subpopulations were analysed by using an indirect immunofluorescence method. RESULTS: Significant differences were established between the test groups and the controls regarding the mean number of CD8+ lymphocytes (LAP > CP and controls; p < 0.05) and CD20+ lymphocytes (LAP/GAP > CP, p < 0.05 and LAP/GAP > controls; p < 0.001). Significant variations in the CD4+/CD8+ ratio were observed (LAP < controls and GAP < controls; p < 0.01), as well as a correlation between the number of T cells and the degree of inflammation. CONCLUSION: In the present study, patients with LAP and patients with GAP were found to have increased numbers of crevicular T-suppressor/cytotoxic and B cells. This supports the hypothesis of a changed immune pathology in patients with aggressive periodontitis.

Periodontal dressing (Vocopac) influences outcomes in a two-step treatment procedure.

OBJECTIVES: It is not clear if periodontal dressing influences the long-term results in a non-surgical treatment procedure. MATERIAL AND METHODS: The periodontal parameters (pre-baseline) of 36 patients with aggressive periodontitis were obtained before the patients were treated initially (1st step) by a dental hygienist, who completely removed the supra- and subgingival concrements. Baseline parameters were raised 3 weeks after the 1st step, before the 2nd therapy step was conducted. It consisted of a non-surgical procedure, which comprised a closed full-mouth manual root curettage (root planing), immediate systemic application of metronidazole, and the placement of a periodontal dressing (Vocopac, Voco). The patients were randomized to two test groups having their periodontal packs removed after 3-4 days (group 1, n=12) and 7-8 days (group 2, n=12), respectively and a control group (n=12) without periodontal dressing. Clinical parameters were raised again after 6 and 24 months. RESULTS: Six and 24 months later, changes in probing pocket depth (PPD) and probing attachment level (PAL) were observed in all three groups compared with baseline, but the difference was significant in group 2 only. In addition, group 2 showed a greater reduction in mean PPD and also a significantly greater gain of attachment in comparison with the controls. CONCLUSION: Wound dressing has a positive effect on clinical long-term results using a two-step non-surgical procedure. Moreover, removing the dressing after 7-8 days leads to clearly better results than removing it earlier.