Microhardness and Ultrastructure of Demineralized Gamma-Irradiated Human Enamel after Diode Laser (980 nm) and Fluoride Surface Treatment

Abstract

were then exposed to demineralizing solution for 72 hours. Examination of slabs was performed using vickers microhardness test and scanning electron microscope; The lowest microhardness was recorded in group G, while inGL and GFL groups it significantly increased. Scanning electron microscope revealed a pronounced loss of central prism core and retention of prism peripheries in group G. Confluence of prismatic and interprismatic structures in GL slabs and irregular rough surface with prismatic boundaries conservation in GFL slabs were detected. Applying laser improved the microhardness and counteracted the adverse effect of gamma radiation. Adding fluoride before laser irradiation had a marked effect on microhardness..

Effect of Diode Laser and Remineralizing Agents on Microstructure and Surface Microhardness of Therapeutic Gamma-Irradiated Primary Teeth Enamel

“…This was demonstrated in the present study by the ESEM, as the irradiated sample showed a merging of both prismatic and interprismatic structures, with distorted prismatic peripheries. This is in agreement with findings by Duruk et al [14], Bakr [21] and Rodrigues et al [31]. Furthermore, this change in the enamel crystalline structure was suggested as one of the factors related to the increased risk of dental caries following radiation therapy.…”

“…Windows of 3 mm × 3 mm were made to standardize the area of all specimens in Groups G-L and L-G that were to be exposed to laser irradiation. The periphery of the windows was coated with nail varnish [21]. The enamel specimens were irradiated in the National Institute of Laser-Enhanced Sciences, Egypt, using a diode laser device (Quanta c 980 nm, Italy) at 2 watt for 15 sec, in a continuous and contact modes, using an optic fiber transmission system with a diameter of 320 µm.…”

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

“…Furthermore, the differences between mean O wt% and C wt% were statistically significant, with decreases recorded in both. Our results assessing the 980 nm diode laser were in agreement with previous studies that have obtained enamel that is less susceptible to acid demineralization due to calcium increases, less-modified phosphorus concentrations, and decreases in carbon and oxygen contents [ 33 , 37 , 53 ].…”

“…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 ].…”

Disorders of Dental Hard Tissues Induced by Radioiodine-131 (I-131) Therapy Used in Differentiated Thyroid Cancer: An In Vitro Study

“…This intracrystalline disorder appearing explains the appearance of a spacing between the prisms of HAP as if the structure of the enamel were to crack. The second effect mentioned in literature as a consequence of exposure to gamma radiation of enamel is demineralization [11,21]. This is manifested by loss of HAP prisms from the enamel surface at the nanostructure level (something similar to what it was began to be observed in Figure 2C.c after 6 h of treatment).…”