Effects of blue-light LED toothbrush on reducing dental plaque and gingival inflammation in orthodontic patients with fixed appliances: a crossover randomized controlled trial

Manphibool et al. BMC Oral Health (2023) 23:293 https://doi.org/10.1186/s12903-023-02977-1 BMC Oral Health Open Access RESEARCH Effects of blue-light LED toothbrush on reducing dental plaque and gingival inflammation in orthodontic patients with fixed appliances: a crossover randomized controlled trial Chavirakarn Manphibool1, Oranart Matangkasombut2, Soranun Chantarangsu3 and Pintu-on Chantarawaratit1* Abstract Background Patients with fixed orthodontic appliances have higher plaque accumulation and gingival inflammation. Our aim was to compare the effectiveness of a light emitting diode (LED) toothbrush with a manual toothbrush in reducing dental plaque and gingival inflammation in orthodontic patients with fixed appliances, and to investigate the effect of the LED toothbrush on Streptococcus mutans (S. mutans) biofilm in vitro. Methods Twenty-four orthodontic patients were recruited and randomly assigned into 2 groups: (1) started with manual and (2) started with LED toothbrushes. After a 28-day usage and 28-day wash-out period, the patients switched to the other intervention. The plaque and gingival indices were determined at baseline and 28 days after each intervention. The patients’ compliance and satisfaction scores were collected using questionnaires. For the in vitro experiments, S. mutans biofilm was divided into 5 groups (n = 6) with 15-, 30-, 60-, or 120-sec LED exposure, and without LED exposure as a control group. Results There was no significant difference in the gingival index between the manual and LED toothbrush groups. The manual toothbrush was significantly more effective in reducing the plaque index in the proximal area on the bracket side (P = 0.031). However, no significant difference was found between the two groups in other areas around the brackets or on the non-bracket side. After LED exposure in vitro, the percentages of bacterial viability after LED exposure for 15–120 s were significantly lower compared with the control (P = 0.006). Conclusion Clinically, the LED toothbrush was not more effective in reducing dental plaque or gingival inflammation than the manual toothbrush in orthodontic patients with fixed appliances. However, the blue light from the LED toothbrush significantly reduced the number of S. mutans in biofilm when it was exposed to the light for at least 15 s in vitro. Clinical Trial Registration Thai Clinical Trials Registry (TCTR20210510004). Registered 10/05/2021. *Correspondence: Pintu-on Chantarawaratit Full list of author information is available at the end of the article © The Author(s) 2023. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data. Manphibool et al. BMC Oral Health (2023) 23:293 Page 2 of 13 Keywords Biofilm, Dental plaque, Fixed orthodontic appliance, Gingival index, Gingival inflammation, LED toothbrush, Orthodontic patient, Plaque index, Streptococcus mutans Background Dental plaque, a structurally and functionally organized biofilm with a diverse microbial composition, is one of the main etiological factors of dental caries and periodontal disease [1]. Fixed orthodontic appliances are a complex apparatus composed of brackets, archwires, and other auxiliary devices that are likely to be plaque retentive areas and limit effective oral hygiene home care [2]. Studies have indicated that patients with fixed orthodontic appliances have higher plaque accumulation [3, 4]. Therefore, this dental plaque can lead to enamel demineralization [1–3], gingival inflammation, and bleeding on probing values [5–9]. Furthermore, the plaque index (PI) and gingival index (GI) reached their maximum values after 3 months of fixed appliance placement [9]. At the microbiological level, placing fixed orthodontic appliances cause a microbial shift towards more pathogenic bacteria, such as streptococci and lactobacilli, which are cariogenic [6, 9]. The colonization of periodontal pathogens in the gingival crevices also escalates [7]. Increases in anaerobic pathogenic bacteria, such as Tannerella forsythia, Campylobacter rectus, and Prevotella nigrescens, were found in the leveling and alignment phases of fixed orthodontic treatment [6, 7]. Due to the difficulties in maintaining adequate oral hygiene during treatment, 10% of post-orthodontic patients experienced more clinical attachment loss compared with the no treatment group [10]. Toothbrushes together with complementary aids (e.g. dental floss, single-tufted brushes, and interdental brushes) and mouthwash are highly recommended for domestic plaque removal in orthodontic patients [11– 13]. However, due to the lack of brushing skills and adequate patient cooperation, dental plaque control remains a significant challenge for orthodontic patients with fixed appliances. To resolve this issue, innovative technologies have been introduced to promote oral hygiene. Antimicrobial photodynamic therapy (aPDT) has been used for decades to treat dental caries, endodontic disinfection, oral candidiasis, and periodontal and periimplant disease [14–21]. In addition, blue light from a light emitting diode (LED) has a bactericidal effect on Streptococcus mutans (S. mutans) and oral biofilms [15, 22–24]. The lethal effect of blue light on S. mutans biofilm was seen after a 7- or 10-min exposure and most of the bacteria that were killed were on the outer surface of the biofilm [22]. An LED toothbrush was introduced that added aPDT using blue light on dental plaque [16, 25–27]. Clinically, the blue LED toothbrush with a 412 nm wavelength significantly reduced dental plaque, gingival bleeding, and inflammation more than the manual toothbrushes [16]. However, research in this area remains limited, and no study has been performed in orthodontic patients with fixed appliances. We hypothesized that the LED toothbrush may be more effective in reducing GI and PI scores. Thus, the aim of this study was to investigate the effectiveness of an LED toothbrush in removing dental plaque and reducing gingival inf (...truncated)