Evaluation of Surface Roughness and Bacterial Adhesion on Tooth Enamel Irradiated With High Intensity Lasers

Abstract

The aim was to evaluate the surface roughness and bacterial adhesion on enamel irradiated with high intensity lasers, associated or not to a fluoride varnish. Eighty fragments of bovine enamel were equally divided in 8 groups (n=10). Group 1 was not treated and Group 2 received only a 5% fluoride varnish application. The other groups were irradiated with an Er:Cr:YSGG (8.92 J/cm 2 ), an Nd:YAG (84.9 J/cm 2 ) and a diode laser (199.04 J/cm 2 ), associated or not to a 5% fluoride varnish. The surface roughness was measured before and after treatments. Afterward, all samples were incubated in a suspension of S. mutans at 37 °C for 24 h. The colony-forming units (CFU) were counted by a stereoscope and the results were expressed in CFU/mm 2 . One-way ANOVA and the Tukey´s test compared the roughness data and the Student´s test compared the results obtained in the bacterial adhesion test (α=5%). The results showed that the irradiated samples without varnish presented the same roughness and the same bacterial adhesion that the non-irradiated samples. However, samples irradiated in the presence of fluoride varnish showed higher surface roughness and higher bacterial adhesion than the non-irradiated samples and those irradiated without varnish. Presence of pigments in the varnish increased the lasers' action on the enamel surface, which produced ablation in this hard tissue and significantly increased its surface roughness. For this reason, the enamel's susceptibility to bacterial adhesion was higher when the irradiation of the samples was made in presence of fluoride varnish.

Biomaterial‐based possibilities for managing peri‐implantitis

“…Many previous works have reported a high positive correlation between surface roughness and bacterial adhesion . Quantitative observation by CFU/mL showed a clear and direct proportional growth of Streptococcus mutans according to the increased roughness values . Similar finding was recorded by another genus of bacteria.…”

Endodontic retreatment of curved root canals using the dual wavelength erbium, chromium:yttrium, scandium, gallium, garnet, and diode 940-nm lasers and the XP-Endoshaper/finisher technique

“…Based on their absorption spectrum, different lasers strike different targets. Erbium lasers which are absorbed in water and hydroxyapatite are capable of ablating dental hard tissues [17]. Several studies using different Er,Cr:YSGG settings endorsed the use of a the 2780-nm wavelength in removing remove the endodontic smear layer created during root canal treatment of straight canals [18][19][20][21].…”

Evaluation of Tooth Surface Irradiated With Erbium: Yttrium Aluminum Garnet and Carbon Dioxide Lasers by Atomic Force Microscopy

“…Depending on the type and irradiation parameters of laser, it can have 5.2% to 100% efficacy. 23 The mechanism of laser for treatment of DH has not been well elucidated. However, Pashley stated that decreased DH might be related to changes in dentinal fluid flow or alterations in activity of nerve fibers.…”

“…22 There is a high positive correlation between surface roughness and bacterial adhesion. 23 Also, increased plaque retention compromises periodontal health. 24 Not many studies have assessed the effect of laser irradiation or the irradiation settings for treatment of DH.…”