CO2 laser and/or fluoride enamel treatment against in situ/ex vivo erosive challenge

Abstract

Objective This in situ/ex vivo study investigated the effect of CO2 laser irradiation and acidulated phosphate fluoride gel (APF) application, separately and in combination, on enamel resistance to erosion.Material and Methods During 2 experimental 5-day crossover phases, 8 volunteers wore intraoral appliances containing bovine enamel blocks which were submitted to four groups: 1st phase - control, untreated and CO2 laser irradiation, 2nd phase - fluoride application and fluoride application before CO2 laser irradiation. Laser irradiation was performed at 10.6 µm wavelength, 5 µs pulse duration and 50 Hz frequency, with average power input and output of 2.3 W and 2.0 W, respectively (28.6 J/cm2). APF gel (1.23%F, pH 3.5) was applied on enamel surface with a microbrush and left on for 4 minutes. Then, the enamel blocks were fixed at the intraoral appliance level. The erosion was performed extraorally 4 times daily for 5 min in 150 mL of cola drink. Enamel loss was measured profilometrically after treatment and after the in situ phase. The data were tested using one-way Repeated Measures Anova and Tukey's test (p<0.05).Results CO2 laser alone (2.00±0.39 µm) did not show any significantly preventive effect against enamel erosion when compared with the control group (2.41±1.20 µm). Fluoride treated enamel, associated (1.50±0.30 µm) or not (1.47±0.63 µm) with laser irradiation, significantly differed from the control.Conclusion The APF application decreased enamel wear; however, CO2 laser irradiation did not enhance fluoride ability to reduce enamel wear.

The Effect of Er:YAG Laser Irradiation Combined With Fluoride Application on the Resistance of Primary and Permanent Dental Enamel to Erosion

“…In our study, enamel micro-hardness of the permanent teeth in the fluoride group significantly decreased after the erosive process. Jordao et al, 24 Sobral et al, 21 and Scatolin et al 33 showed that APF gel decreased the erosive loss of bovine enamel. This controversy in the results may be due to the difference in the study design in terms of the type of tooth, pH cycling and the quantitative method of erosion assessment.…”

“…Many studies have assessed the efficacy of fluoride alone and in combination with other protective measures in the prevention of erosion. 3,24,[39][40][41][42] Laser irradiation alone or combined with fluoride application has also been suggested to increase enamel acid resistance, 31,43 and some studies demonstrated the positive efficacy of Er:YAG laser in increasing enamel resistance against acid attacks and dental caries. 30,31,44 Although both caries and erosion are caused by the demineralization of enamel, their main etiologic factors and mechanism of development are totally different.…”

“…21,22 CO 2 laser has been used for the prevention of erosion in many previous studies. 3,9,12,[23][24][25][26][27] Ramalho et al 3,27 and Esteves-Oliveira et al 28 showed that CO 2 laser irradiation with 0.3 J/cm 2 energy density, 5 µs pulse width, and 226 Hz frequency decreased enamel loss during the erosive process. However, these parameters are not available in clinical laser devices.…”

Non-contact profilometry of eroded and abraded enamel irradiated with an Er:YAG laser

“…Er:YAG lasers (2.94 µm) have been studied regarding the prevention of enamel demineralization and produced positive results when enamel was subjected to cariogenic challenges 4 , 5 . However, few data have shown whether irradiated enamel would react in the same manner when subjected to erosion 12 , 18 , 22 and erosion associated with abrasion challenges.…”

“…Tooth structure loss due to erosive and abrasive challenges is irreversible, and several strategies have been developed with the aim of preventing damage, including the use of high-intensity lasers 12 . To increase the acid resistance of the enamel, the use of an Er:YAG laser has been proposed 4 , 7 .…”