Efficacy of biofeedback therapy via a mini wireless device on sleep bruxism contrasted with occlusal splint: a pilot study

Abstract

The putative causes of bruxism are multifactorial and there are no definite measures for bruxism management. The aim of this study was to evaluate the efficacy of biofeedback therapy on sleep bruxism, compared with occlusal splint. Twenty-four volunteers with sleep bruxism were divided into two groups: the GTB group that were treated with biofeedback therapy (n = 12) and the GTO group that were treated with occlusal splint (n = 12). A mini pressure sensor integrated with a monitoring circuit by use of a maxillary biofeedback splint was fabricated. To foster the relaxation of the masticatory muscles and the nervous system, the wireless device received signals from bruxism events and vibrations alerted the bruxer when the threshold was exceeded. Total episodes and average duration of bruxism events during 8 hours of sleep were analyzed with the monitoring program (TRMY1.0). After 6 and 12 weeks, the episodes (P = 0.001) and duration (P < 0.05) in the GTB group declined dramatically. In contrast, there were no significant differences in the GTO group after the treatment (P > 0.05). Furthermore, the episodes had significant differences between the GTB group and the GTO group after the same period of treatment (P = 0.000). The results suggest that biofeedback therapy may be an effective and convenient measure for mild bruxers, when compared with occlusal splint therapy. The mini wireless biofeedback method may be of value for the diagnosis and management of bruxism in the future.

Keywords: biofeedback; miniaturization; occlusal splint; sleep bruxism; vibration; wireless technology.

Conflict of interest statement

The authors reported no conflicts of interest.

Figures

Fig. 1. The mini wireless biofeedback system.

The signals were transformed from the analog-to-digital converter (ADC) to microcontroller unit (MCU1 and MCU2, MSP430F4152, Texas Instrument, USA), which has ultra lower power consumption with active mode of 200 μA, 1 Mhz and 2.2 v.

Fig. 2. Mini wireless biofeedback device.

A: The margin of the biofeedback splint extends to the lingual surface of the bilateral maxillary second premolars. The cavity design for placement of the pressure sensor, monitoring circuit and button cell. B: Mini-monitoring circuit (18 mm×16 mm×5 mm). C: A maxillary biofeedback splint with pressure sensor, monitoring circuit and button cell embedded(left), a watch style vibration device (right). D: A bruxer with the maxillary biofeedback splint for monitoring and the wireless vibration device. Use of photo was permitted by the study subject.

Fig. 3. A result sample of monitoring device.

The irregular red lines demonstrate bite forces during sleep, the area between a red and blue line (the white arrow) is the interval for analysis, the green rectangles represent episodes of bruxism events.

Fig. 4. The images of polysomography (PSG) and the monitoring device.

A: The comparison of a polysomography and the monitoring device; the PSG demonstrates a bruxism event, which consisted of a series of EMG activities, with the amplitude reaching 20% maximum voluntary contraction (MVC), and the duration is more than 2 seconds. In contrast, the monitoring device demonstrates a series of serrations with the amplitude of force exceeding 20% of the maximum bite force (relative to the baseline) during intercuspal position and the duration was no less than 3 seconds. B: Demonstration of the EMG amplitude of masseter muscle during sleep with no remarkable changes, while the monitoring device also presented the baseline value of bite force without significant changes during sleep simultaneously.

Fig. 5. Efficacy of GTB and GTO after 6 and 12 weeks of therapy.

A: The total episodes in GTB declined dramatically from the beginning to the end of 6 and 12 weeks after biofeedback therapy (P = 0.001), while there are no significant differences in GTO (6 weeks, P = 0.998. 12 weeks, P = 0.970). B: The duration in GTB has significant difference between 6 and 12 weeks after biofeedback therapy compared to baseline (6 weeks, P = 0.026, 12wks, P = 0.012), while similar results cannot be found in GTO (P = 0.999).