Chen H, et al. - Researchers enquired if late bedtime and short nighttime sleep duration at age 18 months exhibited a connection with the risk of caries in deciduous teeth using health check-up data of children born in Kobe City, Japan, who were free of caries at age 18 months and had information on sleep variables at age 18 months and records of dental examinations at age 3 years. Results demonstrated that aORs for children with late or irregular bedtimes compared with those with bedtimes before 21:00 were 1.26, 1.48, 1.74, 1.90 and 1.66 for bedtimes at 21:00, 22:00, 23:00, 0:00, and irregular bedtime, respectively. Furthermore, it was determined that aORs for children with short or irregular sleep duration compared with those with sleep duration of ≥11 hours were 1.30, 1.16, 1.11 and 1.35 for sleep duration of ≤8, 9, 10 hours, and irregular sleep duration, respectively. Hence, it was deduced that late bedtime and short sleep duration were both consistently related to an increased risk of caries in deciduous teeth.