Effects of CO₂laser irradiation on matrix-rich biofilm development formation–an in vitro study

Abstract

BackgroundA carbon dioxide (CO2) laser has been used to morphologically and chemically modify the dental enamel surface as well as to make it more resistant to demineralization. Despite a variety of experiments demonstrating the inhibitory effect of a CO2 laser in reduce enamel demineralization, little is known about the effect of surface irradiated on bacterial growth. Thus, this in vitro study was preformed to evaluate the biofilm formation on enamel previously irradiated with a CO2 laser (λ = 10.6 µM).MethodsFor this in vitro study, 96 specimens of bovine enamel were employed, which were divided into two groups (n = 48): 1) Control-non-irradiated surface and 2) Irradiated enamel surface. Biofilms were grown on the enamel specimens by one, three and five days under intermittent cariogenic condition in the irradiated and non-irradiated surface. In each assessment time, the biofilm were evaluated by dry weigh, counting the number of viable colonies and, in fifth day, were evaluated by polysaccharides analysis, quantitative real time Polymerase Chain Reaction (PCR) as well as by contact angle. In addition, the morphology of biofilms was characterized by fluorescence microscopy and field emission scanning electron microscopy (FESEM). Initially, the assumptions of equal variances and normal distribution of errors were conferred and the results are analyzed statistically by t-test and Mann Whitney test.ResultsThe mean of log CFU/mL obtained for the one-day biofilm evaluation showed that there is statistical difference between the experimental groups. When biofilms were exposed to the CO2 laser, CFU/mL and CFU/dry weight in three day was reduced significantly compared with control group. The difference in the genes expression (Glucosyltransferases (gtfB) and Glucan-binding protein (gbpB)) and polysaccharides was not statically significant. Contact angle was increased relative to control when the surface was irradiated with the CO2 laser. Similar morphology was also visible with both treatments; however, the irradiated group revealed evidence of melting and fusion in the specimens.ConclusionIn conclusion, CO2 laser irradiation modifies the energy surface and disrupts the initial biofilm formation.

Bioactive Dental Adhesive System With tt-Farnesol: Effects on Dental Biofilm and Bonding Properties

“…The media was changed daily without disrupting the biofilm on top of the disks. Biofilm was collected at days 2, 3, and 5 after surface treatment and later sonicated in 5 mL of phosphate-buffered saline (PBS) solution to obtain a homogenized solution (Murata et al, 2008;Salles Branco-De-Almeida et al, 2011;Zancopé et al, 2016).…”

“…The numbers of colonies were normalized and converted into Log 10 values for data interpretation. The CFU assay was performed in triplicate in at least three different experiments (Murata et al, 2008;Salles Branco-De-Almeida et al, 2011;Zancopé et al, 2016).…”

The Impact of CO2 Laser Treatment and Acidulated Phosphate Fluoride on Enamel Demineralization and Biofilm Formation

“…1 The preventive and therapeutic potential of the CO 2 laser for the inhibition of caries on enamel has been discussed. [2][3][4][5][6][7][8][9] However, the parameters for its most effective use are still under debate.…”

“…20 Although the literature is still sparse about the effect of the CO 2 laser on a dental biofilm, the equipment has been tested as an alternative to reduce oral bacterial infections. 2,4,13,21,22 Studies have shown its effectiveness against microorganisms that cause inflammation and dental caries. 4,13,21,22 The main mechanism of the bactericidal effect of the laser is the instantaneous vaporization of the intracellular water.…”

“…2,4,13,21,22 Studies have shown its effectiveness against microorganisms that cause inflammation and dental caries. 4,13,21,22 The main mechanism of the bactericidal effect of the laser is the instantaneous vaporization of the intracellular water. 23 Acidulated phosphate fluoride (APF) gel is one of the most common fluoridated agents used to control enamel demineralization.…”