Seasonality of bruxism: evidence from Google Trends

Seasonality of bruxism and its symptoms has not been tested and reflects a major niche in our understanding and the epidemiology of bruxism. Our aim is to use the Google Trends data to examine whether there was a seasonal pattern in the Google search volumes of bruxism and its symptoms on a population basis.

In the observational, ecological research, we interrogated Google Trends for the following query terms: [bruxism] and [teeth grinding + teeth clenching] to obtain the internet search query volume. These queries were searched within the USA, the UK, Canada, and Australia from January 2004 to December 2017.

The cosinor analysis showed statistically significant seasonal patterns in [bruxism] in the USA (amplitude {A} = 1.91, p = 0.003), Canada (A = 1.91, p < 0.001), and Australia (A = 2.25, p < 0.001), and a trend towards a seasonal variation in the UK (A = 1.11, p = 0.032), with a peak in the winter months and trough in the summer months. Similarly, a statistically significant seasonal variation was found in [teeth grinding + teeth clenching] in the USA (A = 5.54, p < 0.001), the UK (A = 4.36, p < 0.001), and Australia (A = 3.11, p < 0.001), and a trend towards a seasonal variation in Canada (A = 1.53, p = 0.034). The peaks in winter and troughs in summer were reversed by 6 months in countries of northern hemisphere compared to Australia. Time series plots emphasized the consistency of seasonal trend that was ascertained in the cosinor analysis, by repeating in nearly all years.

The preliminary evidence showed a seasonal variation in bruxism and its symptoms, with a peak in the winter months. This novel finding in bruxism epidemiology requires to be verified with clinical studies, and further researches are necessary to elucidate the potential mechanism behind seasonal variation in bruxism.