Quantitative investigation of efficiency of ultraviolet and visible light in eradication of Candida albicans in vitro.

OBJECTIVE: The aim of this study was to quantitatively investigate the efficiency of the ultraviolet (UV) and visible light in eradication of Candida albicans in vitro; in particular, to determine, for selected wavelengths, the specific eradication coefficients and thresholds in terms of energy density levels required to effect 3.0log10 and 4.0log10 reduction. BACKGROUND DATA: Oral candidosis is the most common infection of the oral cavity and is caused by Candida species. The widespread use of topical and systemic antifungal agents as conventional treatment for oral candidosis has resulted in the development of resistance in C. albicans. Therefore, it has become necessary to develop alternative therapies for the treatment of oral candidosis. METHODS: C. albicans ATCC(®) 90028(™) was irradiated with 254 nm, 365 nm, 406 nm, 420 nm, and broadband Xe spectrum. For each wavelength, a fit of experimental data (survival fraction vs. applied energy density) with an exponential decay function enabled estimation of the specific eradication coefficients and thresholds. RESULTS: Based on estimated specific efficiencies (Δ) and eradication thresholds (ET) of the investigated wavelengths, the ranking in eradication efficiency of C. albicans (most to least effective) is: 254 nm (Δ=6.1 mJ/cm(-2), ET99.99=56 mJ/cm(-2)), broadband Xe spectrum (Δ=27.7 mJ/cm(-2), ET99.99=255 mJ/cm(-2)), 365 nm (Δ=4.3 J/cm(-2), ET99.99=39 J/cm(-2)), 420 nm (Δ=0.65 J/cm(-2), ET99.99=6 J/cm(-2)), and 406 nm (Δ=11.4 J/cm(-2), ET99.99=104 J/cm(-2)). CONCLUSIONS: The results provide insight into the wavelength-dependent dynamics of eradication of C. albicans. For each investigated wavelength, the eradication coefficient and corresponding eradication threshold were estimated. The observed different eradication efficiencies are consequence of different spectrally dependent inactivation mechanisms. The established methodology enables unambiguous quantitative comparison of eradication efficiencies of optical radiation and selection of most effective wavelengths for clinical and therapeutic use.

Effect of low-level laser therapy on Candida albicans growth in patients with denture stomatitis.

OBJECTIVE: The purpose of our report is to present the effect of low-level laser therapy on Candida albicans growth and palatal inflammation in two patients with denture stomatitis. BACKGROUND DATA: The most common oral mucosal disorder in denture wearers is denture stomatitis, a condition that is usually associated with the presence of the yeast Candida albicans. Different treatment methods have been suggested to treat this symptom, none of which is proven to be absolutely effective. METHODS: Two denture-wearing patients, both with palatal inflammation diagnosed as Newton type II denture stomatitis were treated with low-power semiconductor diode laser (BTL-2000, Prague, Czech Republic) at different wavelengths (685 and 830 nm) for 5 d consecutively. In both patients, palatal mucosa and acrylic denture base were irradiated in noncontact mode (probe distance of 0.5 cm from irradiated area) with different exposure times-5 min (830 nm, 3.0 J/cm2, 60 mW) and 10 min (685 nm, 3.0 J/cm2, 30 mW). The effect of laser light on fungal growth in vivo was evaluated after the final treatment using the swab method and semiquantitative estimation of Candida albicans colonies growth on agar plates. The severity of inflammation was evaluated using clinical criteria. RESULTS: After lowlevel laser treatment, the reduction of yeast colonies on the agar plates was observed and palatal inflammation was diminished. CONCLUSION: LLLT is effective in the treatment of denture stomatitis. Further placebo controlled studies are in progress.

Fungicidal effect of diode laser irradiation in patients with denture stomatitis.

BACKGROUND AND OBJECTIVE: Denture stomatitis (DS) is a common inflammatory condition that affects denture wearers. The aim of this study was to examine, in vivo, the effect of diode laser irradiation on fungal growth in both the palatal mucosa and in denture base materials, in denture wearing patients. STUDY DESIGN/MATERIALS AND METHODS: In total, 70 patients with clinical study design evidence of DS participated in this parallel, single blind, and placebo controlled study. The subjects were randomly assigned to one of four different treatment regimens: (1) irradiation with a 685 nm wavelength laser for 10 minutes (30 mW); (2) irradiation with a 830 nm wavelength laser for 5 minutes (60 mW). A semiconductor diode laser, BTL-2000 (BTL-2 Dravotnicka Technika, Prague, Czech Republic), was used in both treatment cases using an energy density of 3.0 J/cm(2) and a continuous working mode for five consecutive days; (3) placebo-sham irradiation of patients; (4) antimicotic-self treatment of patient's palatal mucosa with an antifungal oral gel and the use of an antiseptic solution for their dentures. The effect of laser light on fungal growth in vivo was evaluated after final treatment using the swab method and a semi-quantitative estimation of Candida albicans colonies cultivated on agar plates. RESULTS: A fungicidal effect was achieved in the laser treated and antimicotic treated groups, whereas most subjects in the placebo group were found to have unchanged conditions on both their palate (P = 0,004) and dentures (P < 0,001). CONCLUSIONS: Light from a low-power laser (LLLT) may be valuable in the treatment of DS. This is of great importance since the rate of recurrence of disease is high, whereas an optimal treatment modality has not yet been found.