Objective: To compare the effectiveness of LED toothbrush to manual toothbrush in reducing dental plaque and gingival inflammation in fixed orthodontic patients, and to investigate the effect of duration of LED toothbrush exposed to the S.mutans biofilm in vitro. Materials and methods: Fifteen fixed orthodontic patients were recruited to this parallel-group analysis. The patients were randomly divided into 2 groups relying on brushing methods: manual toothbrush and LED toothbrush. Plaque index and gingival index were examined by a calibrated-blinded examiner at baseline and 28 days after brushing period. In vitro part, the S. mutans biofilms were assigned to 5 groups with 6 samples each, depending on the duration of LED exposure, which are 15 seconds, 30 seconds, 60 seconds, 120 seconds, and the control with no LED exposure. Results: Between-group comparisons showed no significant difference in plaque index and gingival index. The LED toothbrush significantly reduced dental plaque at the gingival portion on the bracket side. In vitro part, the percentage of bacterial viability was significantly reduced in 15, 30, 60, 120 seconds group. Conclusion: LED toothbrush did not more effective in reducing dental plaque and gingival inflammation than the manual toothbrush in fixed orthodontic patients. The LED blue light from the LED toothbrush significantly reduced the number of S.mutans in biofilm in vitro when the biofilm was exposed to the light for at least 15 seconds.

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.