Evaluation of the Influence of Er:YAG Laser Parameters on the Effectiveness of Growth Inhibition of Candida Biofilms: An In Vitro Study

Q: Why are Candida biofilms challenging to treat?

Candida biofilms exhibit high tolerance to antifungal drugs and environmental stress, with biofilm-embedded cells reported to be much more resistant than planktonic forms.

Q: How was the Er:YAG laser fluence evaluated in the study?

Biofilms were grown on Sabouraud agar, then subjected to non-contact Er:YAG irradiation across fluences, followed by growth inhibition zone measurement and viability quantification using CFU imprinting.

Q: What overall effect did increasing fluence have on Candida biofilms?

Growth inhibition zones increased significantly with fluence for all Candida species, and mature biofilm viability (CFU counts) decreased significantly as fluence increased, with species-specific optimal ranges.

Sep 30, 2026

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Er:YAG laser fluence is assessed as an adjunct physical disinfection approach against Candida biofilms, which show strong resistance to antifungal therapy. The study quantifies growth inhibition and viability of single-species Candida biofilms grown in vitro on Sabouraud agar. Non-contact irradiation is tested across fluences (0.3–3.4 J/cm2) and incubation times (24–96 h), then mature biofilms are irradiated for 120 s at selected fluences and assessed by CFU imprinting. Higher fluence increases inhibition zones, while CFU viability decreases significantly.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages14

Reading Time35 min

AccessFree to download

Abstract

Background/Objectives

Methods

Results

Conclusions

1. Introduction

1.1 Background

1.2 Er:YAG Laser and Antimicrobial Applications

1.3 Rationale and Aim of the Study

Article Evaluation of the Influence of Er:YAG Laser Parameters on the Effectiveness of Growth Inhibition of Candida Biofilms: An In Vitro Study Diana Dembicka-Ma˛czka 1,*, Jakub Fiegler-Rudol 2, Małgorzata K˛epa 3, Dariusz Skaba 2, * and Rafał Wiench 2 Academic Editor: Denis Bourgeois Received: 3 December 2025 Revised: 15 December 2025 Accepted: 18 December 2025 Published: 19 December 2025 Copyright: © 2025 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license. 1 Dental Office, Artistic Smile Studio, 61/1 Krakowska Street, 33-100 Tarnów, Poland 2 Department of Periodontal and Oral Mucosa Diseases, Faculty of Medical Sciences in Zabrze, Medical University of Silesia, 40-055 Katowice, Poland; [rwiench@sum.edu.pl](rwiench@sum.edu.pl) (R.W.) 3 Department of Microbiology, Faculty of Pharmaceutical Sciences in Sosnowiec, Medical University of Silesia, 41-200 Sosnowiec, Poland; [mkepa@sum.edu.pl](mkepa@sum.edu.pl) * Correspondence: [dianadembicka@vp.pl](dianadembicka@vp.pl) (D.D.-M.); [dskaba@sum.edu.pl](dskaba@sum.edu.pl) (D.S.) Abstract Background/Objectives: Candida biofilms exhibit high resistance to antifungal treatment, motivating investigation of adjunctive physical disinfection methods. To quantitatively assess the effect of Er:YAG laser fluence on growth inhibition and viability of singlespecies Candida biofilms in vitro using a 7 mm full-beam handpiece. Methods: Biofilms of Candida albicans ATCC 10231, C. glabrata ATCC 90030, C. parapsilosis ATCC 22019, and C. krusei ATCC 6258 were grown on Sabouraud agar. In phase 1, growth inhibition zones (GIZs) were evaluated after non-contact Er:YAG irradiation (2 Hz, 300 µs, 10 mm distance, no air or water spray) at fluences from 0.3 to 3.4 J/cm2, with incubation for 24 to 96 h. In phase 2, 96 h mature biofilms were irradiated for 120 s at 0.8, 1.0, 1.5, or 2.0 J/cm2, and viability was quantified by colony-forming unit (CFU) imprinting. All experimental conditions were tested in quadruplicate. Results: GIZ diameters increased significantly with fluence for all species (p < 0.05) and remained stable up to 96 h. At the highest fluence, mean GIZs reached approximately 8.0 mm for C. albicans, 7.7 mm for C. parapsilosis, 7.0 mm for C. krusei, and 5.2 mm for C. glaxfbrata. In mature biofilms, CFU counts decreased significantly with increasing fluence (p < 0.05) . For C. albicans, CFUs were reduced from 164 .0 ± 25. 1 at 0 .8 J/cm2 to 16 .5 ± 5.2 at 2 .0 J/cm2, while C. glabrata decreased from 103.5 ± 5.4 to 20.8 ± 1.7. C. parapsilosis and C. krusei showed maximal reductions at 1.0–1.5 J/cm2, followed by partial CFU rebound at 2.0 J/cm2. Conclusions: Er:YAG irradiation delivered over a large, uniformly illuminated area induces stable, fluencedependent inhibition and significant reduction of Candida biofilm viability in vitro. Optimal fluence ranges are species specific, underscoring the need for parameter optimization and further evaluation in more complex biofilm models before clinical extrapolation. Keywords: Er:YAG lasers; biofilms; Candida; oral candidiasis; laser therapy; in vitro techniques 1. Introduction 1.1. Background Fungal infections caused by yeasts of the genus Candida represent a significant clinical problem, particularly in immunocompromised patients, individuals with diabetes, those receiving prolonged antibiotic therapy, and denture wearers [1–3] . Candida albicans, C. glabrata, C. parapsilosis, and C. krusei are among the species most frequently associated with oral candidiasis and denture-related stomatitis [1,2] . A major virulence factor of these organisms is their ability to form biofilms, structured microbial communities embedded inan extracellular matrix composed of polysaccharides, proteins, and extracellular DNA [4] . Biofilm formation markedly increases tolerance to antifungal agents and environm

FAQs

Why are Candida biofilms challenging to treat?

Candida biofilms exhibit high tolerance to antifungal drugs and environmental stress, with biofilm-embedded cells reported to be much more resistant than planktonic forms.

How was the Er:YAG laser fluence evaluated in the study?

Biofilms were grown on Sabouraud agar, then subjected to non-contact Er:YAG irradiation across fluences, followed by growth inhibition zone measurement and viability quantification using CFU imprinting.

What overall effect did increasing fluence have on Candida biofilms?

Growth inhibition zones increased significantly with fluence for all Candida species, and mature biofilm viability (CFU counts) decreased significantly as fluence increased, with species-specific optimal ranges.

Sep 30, 2026

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