Cavity Disinfection With a 445 nm Diode Laser Within the Scope of Restorative Therapy – A Pilot Study

Abstract

Introduction: Cavity disinfection is necessary to prevent a progressive infection of the crown dentin and pulp. Increasing intolerance and resistance to antiseptics and antibiotics as well as the controversy over the effects of those on the dental hard tissue and composite have prompted the investigation of alternative treatment options. The objective of this pilot study is to evaluate the antibacterial potential of a diode laser with a wavelength of 445 nm in the cavity preparation using the bacterium Streptococcus salivarius associated with caries in conjunction with the characteristics and influences of dentin on light transmission. Methods: The bactericidal effect of the laser irradiation was determined in culture experiments by using caries-free human dentin samples on bacteria-inoculated agar. For this, dentin discs (horizontally cut coronal dentin) of 500 µm and 1000 µm thicknesses were produced and irradiated with the laser with irradiation parameters of 0.7-1 W in a cw-mode and exposure times of between 5-30 s. Based on the different sample thicknesses, the penetration depth effect of the irradiation was ascertained after the subsequent incubation of the bacteria-inoculated agar. Additional influential parameters on the irradiation transmission were investigated, including surface moisture, tooth color as well as the presence of a smear layer on the dentin surface. Results:The optical transmission values of the laser radiation for dentin were significantly dependent on the sample thickness (P = 0.006) as well as its moisture content (P = 0.013) and were independent of the presence of a smear layer. There was a 40% reduction in bacteria after the radiography of the 500-µm-thick dentin samples, which was shown as the lowest laser dose (443 J/cm 2 ). Conclusion:These findings indicate that the diode laser with light emission at a wavelength of 445 nm is interesting for the supportive cavity disinfection within the scope of caries therapy and show potential for clinical applications.

The Effect of Diode Laser on Viability and Antibiotic Sensitivity of Streptococcus mutans Isolated From Dental Caries

“…The changes in sensitivity of bacteria to an antibiotic after exposure to diode laser are affected by a different laser aspects such as wavelength, the intensity of energy, time of exposure, and modality of propagation of laser irradiation [11], [21]. Also, exposure to diode laser may cause changes in bacterial efflux pump that accounted for bacterial resistance to antibiotics such as Beta-lactams and aminoglycoside [43]. In addition, it may cause bacterial failure in the production of target enzymes that chemically modified a special antibiotic leading to increased bacterial sensitivity to these antibiotics [13].…”

Using Femtosecond Laser Light-Activated Materials: The Biomimetic Dentin Remineralization Was Monitored by Laser-Induced Breakdown Spectroscopy

“…Studies in the literature have shown that diode laser treatment at 445 nm prevents enamel demineralization and cavity disinfection [ 26 , 27 , 28 ]. The results of this study agree that 445 nm is the best wavelength, and the results presented herein show that using a femtosecond laser with Moringa oleifera not only prevents demineralization but in fact causes remineralization.…”

Antibacterial Effects of the Novel Blue Laser and Erbium Chromium Laser on Enterococcus Faecalis in Root Canal Dentin with Different Thicknesses

“…Due to the infiltration of bacteria into the dentinal tubules, the depth of the dentinal tubules cannot be properly cleared by the conventional methods [24,25]. erefore, to investigate the effects of dentin thickness on the bactericidal effects of the lasers, unlike previous studies in which the bacterial suspension was directly inoculated into the root canal and the laser fiber tip was in direct contact with the bacteria inside the dental canal [26], in this study, the dentinal sections with thicknesses of 300, 500, and 1,000 μm were prepared and indirect laser irradiation was used, i.e., the laser fiber was placed on the opposite side of the bacterial suspension.…”