Influence of Cavity Preparation with Er,Cr:YSGG Laser and Restorative Materials on In Situ Secondary Caries Development

Abstract

Objective: The aim of this study was to evaluate the influence of cavity preparation and restorative materials containing fluorides in the prevention of secondary caries lesion development in situ. Methods: A total of 120 blocks obtained from human teeth were divided into two groups and standardized cavities were prepared using diamond burs (DB) or Er,Cr:YSGG-laser [20 Hz, 4.0W, 55% water, 65% air (LA)]. They were divided into three subgroups according to the restorative material (n = 20): glass-ionomer cement (GI), resin modified glassionomer (RM) or composite resin (CR). Blocks were fixed in palatal intra-oral appliances worn in situ by 20 human volunteers, who dropped 20% sucrose solution eight times daily. After 21 days, blocks were removed and restorations were cross-sectioned to evaluate microhardness [Knoop hardness number (KHN)] underneath enamel surface from 30 to 200 lm. Factors ''cavity preparation,'' ''restorative materials,'' and ''depth'' were evaluated by three way ANOVA, followed by Tukey test ( p < 0.05). Results: The results showed lower microhardness in cavities prepared with DB than in cavities prepared with LA. At 30 lm, there were no statistical significant differences with regard to ''cavity preparation'' or ''restorative materials'' factors. In depth evaluation, the enamel microhardness progressively increased as a function of depth for the GI groups. In the groups prepared with LA at 60 lm/90 lm, there were no significant differences between GI and RM materials, whose microhardnesses were significantly higher than that of CR. Conclusions: Cavity preparation using Er,Cr:YSGG laser increases caries resistance of enamel walls, and reduce caries lesion depth development regardless of fluoride presence in the restorative material. CR showed higher caries lesion development than GI, and RM showed intermediate results.

The effects of combining erbium, chromium: Yttrium-scandium-gallium-garnet laser irradiation with fluoride application in controlling the progression of enamel erosion

“…The attraction between water and hydroxyl ions in the tooth structures results in chemical changes in the mineral content of the enamel as temperature increases due to laser irradiation, which promotes the formation of structures with high acid resistance ( Bachmann et al, 2004 ). It is used to prevent caries, reduce the loss of hardness associated with their development, and can produce a cariostatic potential comparable to that produced by fluoridated dentifrice ( Altinok et al, 2011 , Jorge et al, 2015 ).…”

Influence of Er, Cr: YSGG (2780 nm) and Nanosecond Nd: YAG Laser (1064 nm) Irradiation on Enamel Acid Resistance: Morphological and Elemental Analysis

“…Er, Cr: YSGG laser emitted at 2780 wavelength is well absorbed by water and hydroxyl radical in the hydroxyapatite. Thus, this type of laser has the potentiality to improve enamel acid resistance and prevent mineral loss by inducing chemical and morphological changes in enamel without an excessive increase of heat [9], [10].…”

Comparative Evaluation of Influence of Nd:YAG Laser (1064 nm) and 980 nm Diode Laser on Enamel around Orthodontic Brackets: An In Vitro Study

“…It is well known that increases in Ca wt% and P wt% increase the resistance of enamel to dissolution [ 7 , 8 , 9 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 33 , 37 , 39 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 ]; however, the mean of oxygen wt% before and after irradiation for both wavelengths were about the same, while that for carbon was lower after irradiation with both lasers. The content of carbon in teeth can be correlated with various factors, such as enamel maturity, dietary intake, caries susceptibility, and the hypoplastic status of the enamel [ 32 ].…”

“…Studies conducted on laser radiation by several authors have led to the encouragement of its use in prevention. Wavelengths that have achieved a marked acid resistance of the enamel are 9.6 μm and 10.6 μm (CO 2 ) [ 14 ], 2.94 μm (Er:YAG) [ 15 ], and 2.79 μm (Er:YSGG) [ 16 , 17 ]. Nd:YAG (1.064 µm) and Argon [ 18 ] lasers have also been shown to be successful, with promising results in reducing enamel solubility.…”