• Ichaya Yiemwattana

Objective To evaluate the changes in subgingival bacterial counts and proportions and clinical parameters after subgingival scaling with ultrasonic minitip curet-like tips in the patients with chronic periodontitis.

Materials and methods Twelve patients with a total of 97 sited of 3.1-5.0 mm - pocket depth and 43 sites of 5.1 - 7.0 mm - pocket depth participated in this study. Microbiological monitoring was carried out with phase-contrast microscopy and clinical measurements consisting of probing depth (PD) and clinical attachment level (CAL) for 8 weeks. Microbiological assessment of the subgingival flora counts was transformed by the logarithm base 10 to stabilize the variance of the total count. Intergroup differences of counts in each microbial group were determined by a nonparametric Mann-Whitney U test and intragroup differences by a Wilcoxon signed-rank test. Intergroup differences of PD and CAL were tested with an unpaired t test and intragroup differences by a paired t test.

Results Intergroup differences in changing the percentage of all bacterial forms were statistically significant at week 8 (p < .05). Proportions of coccoid cells and non-motile rods were increased while those of motile rods and spirochetes were reduced in both groups at all four-time intervals, when compared to the baseline data (p < .05). Nevertheless, sites with a deeper pocket depth showed higher proportions of spirochetes. Intergroup differences in pocket reduction and clinical attachment gain were statistically significant throughout the experimental periods (p < .05). A significant decrease in PD and a gain of CAL were also found in both groups, when compared to the baseline data (p < .05).

Conclusion Application of subgingival scaling with ultrasonic minitip curet-like tips for subgingival scaling is capable of altering the subgingival bacterial counts and proportions and improving clinical response. The initial depth of pocket appeared to be related to the percentage of subgingival bacterial forms after treatment.

(CU Dent J. 2006;29:22-32)