Effects of Er,Cr:YSGG laser irradiation on the root surface: morphologic analysis and efficiency of calculus removal.

BACKGROUND: This in vitro study was performed to determine the appropriate power output setting for an erbium, chromium-doped:yttrium, scandium, gallium, and garnet (Er,Cr:YSGG) laser used in periodontal pocket irradiation by examining the morphologic alterations of the root surfaces and the efficiency of calculus removal. METHODS: Sixty-five non-carious extracted human teeth were used in this study. For morphologic analysis of the root surface, the clean, single roots of 22 teeth were separated into 91 pieces, and these pieces were immersed in acrylic resin. The specimens with root-surface exposure were prepared and divided randomly into three groups: a control group (N=8), an irradiation without water group (no water [NW] group; N=39), and an irradiation in water to simulate the conditions in a periodontal pocket group (in water [IW] group; N=44). The power output settings for laser irradiation were 0.5, 1.0, 1.5, and 2.0 W for each group. The roughness (Ra), depth (Z), and width (X) of the disk specimens were determined after laser irradiation. Eight other single-rooted teeth were examined by scanning electron microscopy (SEM) after laser irradiation under the same conditions. Thirty-five single- or multirooted teeth with heavy subgingival calculus were used to test the efficiency of laser scaling. The efficiency of calculus removal was quantified by measuring the time needed to remove the calculus completely using the laser. RESULTS: The mean Ra and Z values in the IW group were significantly higher than in the NW group with the same power output. In addition, these values with 0.5- and 1.0-W power output settings were significantly lower than with 1.5- and 2.0-W settings in the NW and IW groups. No obvious morphologic differences could be found between the 0.5- and 1.0-W power output specimens under SEM. Additionally, thermal alterations, i.e., carbonization or melting, were completely absent in the IW group. Regarding the efficiency of calculus removal, the 0.5-W setting (0.11+/-0.036 mm2/second) was significantly inferior to the 1.0-W setting (0.27+/-0.043 mm2/second). However, there was no significant difference between 1.0- and 1.5-W (0.36+/-0.11 mm2/second). The 2.0-W setting (0.63+/-0.272 mm2/second) was much more efficient but resulted in significant morphologic alterations. CONCLUSIONS: Based on these findings, it is appropriate to use a 1.0-W power output setting with an Er,Cr:YSGG laser for root scaling. This may be done without any conspicuous morphologic alterations to the root surface and with acceptably efficient removal of calculus.

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.