Combined effects of Nd:YAG laser irradiation with local antibiotic application into periodontal pockets.

The purpose of the present study was to assess the effects of Nd:YAG laser irradiation into periodontal pockets with or without the combination of local antibiotic application on clinical parameters and microbiological prevalence. Sixteen patients, each of whom had 4 or more sites with probing depth e x 4mm were included in this study. They were monitored clinically and microbiologically at baseline, 1 and 3 months after the treatment. Subgingival plaque samples were taken from periodontally involved sites with a probing depth of e x 4mm. A total of 135 sites were randomly assigned to the following treatments; Nd:YAG laser alone (Group L: 10 pps, 200 mJ for 90 sec, n = 37), local minocycline administration following laser treatment (Group LP, n = 33), povidone-iodine irrigation following laser treatment (Group LI, n = 33), and control group (Group C: sham procedure, n = 32). The prevalence of 18 subgingival taxa were determined using the checkerboard technique. The mean value of the pocket probing depth (PPD) significantly decreased in Group L, Group LP and Group LI, and the mean clinical attachment loss (CAL) decreased in all three treatment groups. Multivariate logistic regression analysis showed that Group LP showed the most improvement in PPD or CAL at 3 months. The proportions of Porphyromonas gingivalis, Tannerella forsythia (formerly Bacteroides forsythus) and Prevotella intermedia were significantly lower in Group LP than in Group L after 3 months. These results showed that Nd:YAG laser irradiation plus local minocycline provides a much greater reduction in PPD, CAL and the amount of periodontopathogenic bacteria than laser irradiation alone in periodontitis patients.