title: Effect of gallium-arsenic laser on photosensitized periodontopathic anaerobic organisms: Anin vitrostudy.
abstract: BACKGROUND
  The mainstay of periodontal therapy is mechanical removal of subgingival plaque. There is considerable interest in supplementing it with the use of antibiotics and antiseptics. Many drawbacks are associated with these adjunctive pharmacological regimens such as development of resistance to antibiotics and disruption of microflora of the gastrointestinal tract. Hence, alternate means of killing subgingival bacteria are clearly desirable. One such method is the use of laser.
  
  
  OBJECTIVE
  This study aimed to investigate antibacterial capabilities of gallium-arsenic (Ga-As) laser on photosensitized periodontopathic organisms. The three bacteria selected for the study werePorphyromonas gingivalis,Fusobacterium nucleatum, andPrevotella intermedia.
  
  
  METHODS
  The subjects for the study were selected from the patients visiting the Department of Periodontics, Karnataka Lingayat Education Society's Institute of Dental Sciences, Belgaum.
  
  
  METHODS
  In vitrostudy design.
  
  
  METHODS
  Subgingival plaque samples collected from chronic periodontitis patients were cultured anaerobically for 72 h. Predetermined number of colonies of each bacterium was taken and was then divided into cases and control groups. Both groups were photosensitized using toluidine blue O (TBO) dye and the case groups were irradiated with Ga-As laser. Bacterial colonies were then serially diluted and were incubated for subculture. After incubation period, the number of viable bacterial count was performed.
  
  
  METHODS
  Wilcoxon-signed rank test was carried out to determine significance of reduction on subsequent dilution within the bacterial group. Mann-Whitney U-test was performed to determine the significance of reduction between cases and control of particular bacterial group.
  
  
  RESULTS
  The results revealed substantial reduction in the viable bacterial count.F. nucleatumwas found to be most sensitive to killing by laser irradiation followed byP. intermediaand thenP. gingivalis. Further, the TBO dye per se did not have any significant bactericidal effect.
  
  
  CONCLUSIONS
  Photodynamic Therapy may prove to be a promising method for eradicating periodontopathic bacteria in near future.
authors.affiliation: Department of Periodontics, Government Dental College and Hospital, Jaipur, Rajasthan, India.
authors.forename: Setu
authors.initials: S
authors.lastname: Mathur
authors.affiliation: Department of Periodontics, KLES's Institute of Dental Sciences, Belgaum, Karnataka, India.
authors.forename: Shaila Veerappa
authors.initials: SV
authors.lastname: Kothiwale
authors.affiliation: Department of Pathology, Mahatma Gandhi Medical College and Hospital, Jaipur, Rajasthan, India.
authors.forename: Buddhi Prakash
authors.initials: BP
authors.lastname: Nag
authors.affiliation: Department of Conservative and Endodontics, Mahatma Gandhi Dental College and Hospital, Jaipur, Rajasthan, India.
authors.forename: Tanu
authors.initials: T
authors.lastname: Mathur
authors.affiliation: Department of Periodontics, CSMSS Dental College, Aurangabad, Maharashtra, India.
authors.forename: Ashoka
authors.initials: A
authors.lastname: Bhansali
authors.affiliation: Department of Endodontics, Government Dental College and Hospital, Jaipur, Rajasthan, India.
authors.forename: Rohit Kumar
authors.initials: RK
authors.lastname: Khatri
keywords: Fusobacterium nucleatum; Porphyromonas gingivalis; Prevotella intermedia; periodontitis; photodynamic therapy