Clinical evaluation of an automatic flossing device vs. manual flossing.

The aim of this study was to compare the effectiveness of an automatic flossing device to manual flossing. A total of seventy adult subjects (20 males and 50 females) were stratified into two groups balanced for age, sex, modified gingival index (MGI), plaque index (PI) and bleeding sites (Eastman Bleeding Index) using screening data. One group was randomly assigned the automatic power flosser and the other group was assigned manual dental floss. The subjects were instructed to brush their teeth twice a day (in the morning and before bedtime) for 30 seconds using the provided manual toothbrush and toothpaste. They were also to use their assigned dental floss or automatic power flosser once in the morning following toothbrushing. There was no significant difference between manual flossing and automatic flossing with respect to the MGI and the BI. There was, however, a significant difference at day 15 in the PI; however, this difference was only 0.73%. There was no significant difference in the PI at day 30 between the two techniques. The statistically significant difference noted in the interproximal PI at both day 15 and day 30 was less than 2%. Since the differences in plaque scores between the groups were so small, there was no apparent impact on gingival health since both flossers resulted in similar health benefits. Since there was a marked preference for the automatic flosser, patient compliance with the automatic flossing device may be better than with manual floss. Therefore, overall gingival health may benefit from this device.

Effect of protoporphyrin IX limitation on porphyromonas gingivalis.

Porphyromonas gingivalis has been shown to require hemin or hemoglobin for in vitro growth. We have previously shown that protoporphyrin IX and inorganic iron can replace the hemin requirement, suggesting that the hemin requirement of this microorganism is actually a porphyrin requirement. We examined the effect of protoporphyrin IX limitation to P. gingivalis strain A7A1-28 in the presence of sufficient iron on growth characteristics, proteolytic enzyme production, virulence in a mouse abscess model, and expression of membrane proteins. Bacterial cells were grown in medium varying between 0 to 5 microM reduced growth by at least 50%. Protoporphyrin IX availability did not affect proteolytic enzyme production or virulence in a mouse abscess model. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of membrane preparations demonstrated that protoporphyrin IX limitation induced the expression of new proteins at 42, 34, 30, 29, and 18 kDa and suppressed the production of proteins at 47, 27, 17, and 15 kDa. These studies suggest that in vivo protoporphyrin availability may modulate membrane protein expression and in turn affect host immune responses against P. gingivalis.