In vitro assessment of laser efficiency for caries prevention in pits and fissures

Abstract

This study aimed to assess the in vitro efficacy of the lasers Er:YAG, Nd:YAG, and CO(2) operating in the low energy mode for caries prevention in pits and fissures. Forty-five caries-free enamel occlusal sections were randomly divided into three groups: G1 - Er:YAG (80 mJ/2 Hz); G2 - Nd:YAG Laser (1 W and 10 Hz); and G3 - CO(2) Laser (0.4 W and 20 Hz). After surface treatment, the samples were submitted to challenge with acid consisting of a 10-day immersion in demineralizing (6 h) and remineralizing solution (18 h). Next, enamel demineralization was quantitatively evaluated by subsurface microhardness test and polarized-light microscopy (PLM, mm(2)) and qualitatively assessed by scanning electron microscopy. The Wilcoxon test was used for comparison of each group with its own control. ANOVA (α = 5%) was employed for comparison among groups, and Fisher's LSD multiple comparison test was applied, to check the difference in means. Concerning the microhardness analyses, statistical difference between control, and experimental areas was only detected for the CO(2) group. Experimental values were higher than the controls. As for PLM analyses, smaller demineralized areas were measured for G2 (Nd:YAG) and G3 (CO(2)) compared with the control areas. In conclusion, the present findings suggest that the CO(2) laser should be selected in order to increase the enamel resistance to acid in pits and fissures.

Shear bond strength of pit and fissure sealants on permanent teeth after several etching protocols: In vitro study

“…12,19 Nevertheless, laser treatment requires specific considerations as the use of correct tip, 8,15,20 adequate energy, otherwise could result in sub or over ablative energy, causing either flacking 8,18,21,22 or vitrification. 8,20 Furthermore, dental tissues response depends on several conditions such as focal distance, irriga- tion, among others; 15,23 in addition, ablation process could lead to produce a microretentive surface on enamel. 20,22 Regarding the self-etching adhesive employed in this study, it had similar SBS values to all the groups, except for group VI (in combination with previous Er:YAG laser irradiation).…”

Erbium Lasers for the Prevention of Enamel and Dentin Demineralization: A Literature Review

“…56 In contrast, the other studies reported that the results of Er:YAG laser in occlusal fissure caries prevention were similar to those achieved in the control portion of the substrate. 45,75 One hypothesis given by the authors for these findings could be related to the use of water cooling during irradiation. The irregularity of the occlusal surface could promote water buildup at the bottom of the fissures, and the necessary heating temperature was not reached.…”

“…The irregularity of the occlusal surface could promote water buildup at the bottom of the fissures, and the necessary heating temperature was not reached. 45,53 However, the first study that applied higher energy densities (64-105 J/cm 2 ) 56 also used water cooling during irradiation. Most likely, when water cooling is applied during irradiation, higher energies should be used in order to achieve the necessary heating, as indicated in the previous paragraph.…”

“…45,56,75 The first in vitro study applied ablation parameters on occlusal surfaces using Er:YAG (2 Hz, 135 mJ, 64 J/cm 2 ) and Er:YSGG (2 Hz, 454 mJ, 105 J/cm 2 ) with water cooling, 56 and the other studies performed in vitro and in situ studies and applied lower energy parameters (2 Hz, 80 mJ, 1.26 J/cm 2 ) with water cooling. 45,75 Only the first study cited that applied higher energy densities showed positive results, consisting of a 50% inhibition of caries progression for the Er:YAG laser (64 J/cm 2 ) and 72% caries inhibition for the Er:YSGG laser (105 J/cm 2 ) when compared with the control group. 56 According to the authors, as a beneficial side effect of peripheral heat deposition during the laser procedure, the walls of the prepared cavity may acquire an increased resistance to decay.…”

Chemical Changes of Enamel Produced by Sodium Fluoride, Hydroxyapatite, Er:YAG Laser, and Combined Treatments

“…There are dental surfaces where caries develop more frequently [2,3], including the occlusal surfaces [3,4]. This is mainly due to the morphology of these surfaces, which are characterized by pits and fissures that favor the accumulation and proliferation of pathogenic caries organisms [2,5,6].…”