Antibacterial action of photoactivated disinfection {PAD} used on endodontic bacteria in planktonic suspension and in artificial and human root canals.

Objectives: To measure antibacterial action of photoactivated disinfection (PAD) on endodontic bacteria in planktonic suspension and root canals.

Methods: Four bacteria, Fusobacterium nucleatum,Peptostreptococcus micros, Prevotella intermedia and Streptococcus intermedius, were tested in suspension. After mixing equal volumes of Tolonium chloride and bacterial suspension for 60s, each 200 microL of concentration (>10(6)cfu mL(-1)) was irradiated with light at 633+/-2 nm.

The photo-activated antibacterial action of toluidine blue O in a collagen matrix and in carious dentine.

The main aim of this study was to determine the susceptibility to photo-activated disinfection (PAD) of Streptococcus mutans when the organism was present in a collagen matrix--an environment similar to that which would exist within a carious tooth. In addition, the susceptibility to PAD of bacteria present in carious human teeth was also determined. Light was delivered to the collagen and teeth using a system comprising a 0.

The effect of variable energy input from a novel light source on the photoactivated bactericidal action of toluidine blue O on Streptococcus Mutans.

Although the combination of toluidine blue O (TBO) dye and laser light at a wavelength of 633 nm has a bactericidal effect, light from laboratory lasers can only be directed externally at a bacterial colony or suspension. In this study a novel delivery system guided the laser light to an 800-micrometer diameter spherical tip (an isotropic tip) from which light radiated producing a uniform sphere of light within the colony or suspension. The system was highly effective in killing TBO-treated Streptococcus mutans NCTC 10449 in stirred planktonic suspension, killing at least 10(9 )cfu/ml.

Comparison of laser-assisted and conventionally sutured microvascular anastomoses by bursting pressure: a reanalysis and further studies.

Methods of testing the strength of microvascular anastomoses are reviewed historically, in the light of recent applications to laser-assisted microvascular anastomosis techniques. The results of two experiments using hydrostatic distension to bursting point to determine the strengths of laser-assisted and conventionally sutured anastomoses of rat arteries and veins are presented. Considerable variation of the bursting pressures was found at any given time after anastomosis, and by the third postoperative day, the sutured vessels showed a significant fall in strength to their weakest level, with not as great a fall in the laser group.

Medical lasers.

There are now a variety of mechanisms governing the interaction of laser light with tissue. These are discussed from a scientific viewpoint and in relation to particular laser systems. Clinical applications, taking advantage of both traditional and newer forms of interaction, are outlined.