ABSTRACT
We have found that broadband light (380 to 520 nm) rapidly and selectively kills oral black-pigmented bacteria (BPB) in pure cultures and in dental plaque samples obtained from human subjects with chronic periodontitis. We hypothesize that this killing effect is a result of light excitation of their endogenous porphyrins. Cultures of Prevotella intermedia and P. nigrescens were killed by 4.2 J/cm2, whereas P. melaninogenica required 21 J/cm2. Exposure to light with a fluence of 42 J/cm2 produced 99% killing of P. gingivalis. High-performance liquid chromatography demonstrated the presence of various amounts of different porphyrin molecules in BPB. The amounts of endogenous porphyrin in BPB were 267 (P. intermedia), 47 (P. nigrescens), 41 (P. melaninogenica), and 2.2 (P. gingivalis) ng/mg. Analysis of bacteria in dental plaque samples by DNA-DNA hybridization for 40 taxa before and after phototherapy showed that the growth of the four BPB was decreased by 2 and 3 times after irradiation at energy fluences of 4.2 and 21 J/cm2, respectively, whereas the growth of the remaining 36 microorganisms was decreased by 1.5 times at both energy fluences. The present study suggests that intraoral light exposure may be used to control BPB growth and possibly benefit patients with periodontal disease.
Subject(s)
Dental Plaque/microbiology , Light , Porphyromonas gingivalis/radiation effects , Prevotella/radiation effects , Streptococcus constellatus/radiation effects , Chronic Disease , Colony Count, Microbial , Humans , Nucleic Acid Hybridization , Periodontitis/microbiology , Periodontitis/therapy , Phototherapy , Pigments, Biological/metabolism , Porphyrins/metabolism , Porphyromonas gingivalis/classification , Porphyromonas gingivalis/genetics , Porphyromonas gingivalis/growth & development , Prevotella/classification , Prevotella/genetics , Prevotella/growth & development , Prevotella intermedia/classification , Prevotella intermedia/genetics , Prevotella intermedia/growth & development , Prevotella intermedia/radiation effects , Prevotella melaninogenica/classification , Prevotella melaninogenica/genetics , Prevotella melaninogenica/growth & development , Prevotella melaninogenica/radiation effects , Streptococcus constellatus/classification , Streptococcus constellatus/genetics , Streptococcus constellatus/growth & developmentABSTRACT
The objective of this paper was to determine the quantitative bactericidal efficiency of ultrasonic in the root canal. Four test organisms found frequently in the root canal were compared. The result showed ultrasonic can kill the test organisms effectively in the root canals. The best bactericidal efficiency occurred at 4 or 5 min. of ultrasonic though the more efficiency as the time longer. Bactericidal irrigation could increase the bactericidal efficiency of ultrasonic and its bactericidal action similar to irrigation bactericidal property.
Subject(s)
Dental Pulp Cavity , Pulpitis/therapy , Ultrasonic Therapy , Actinomyces/radiation effects , Enterococcus faecalis/radiation effects , Humans , Prevotella melaninogenica/radiation effects , Root Canal IrrigantsABSTRACT
Among 51 strains of anaerobic gram-negative cocci belonging to the family Veillonellaceae, all strains of Veillonella (V. parvula and V. alcalescens) displayed red fluorescence under long-wave (366 nm) ultraviolet light, whereas no Acidaminococcus or Megasphaera demonstrated fluorescence. In contrast to Bacteroides melaninogenicus, growth of Veillonella does not require hemin and menadione, and flourescence is rapidly lost upon exposure to air. The fluorescent component of a strain of V. parvula examined could not be extracted in solution with water, ether, methanol, or chloroform, but was readily extracted with 0.4 N NaOH. Spectrophotofluorometrically, the fluorescence maximum of this extract was 660 nm with an excitation maximum of 300 nm, when measured at pH 7.2 and 25 C. Coupled with the Gram stain, ultraviolet fluorescence may be a useful tool for rapid screening of Veillonella and is particularly helpful for detection and, isolation of this organism from mixed culture.
