Take care of your teeth if you enjoy catching Zs. Researchers in Japan looked at over 23,000 elderly people with an average age of 73. The subjects reported on the number of hours of sleep they get per day, as well as how many teeth they have. Most claimed to get seven hours of sleep per night, and 14.7 percent were missing at least once tooth. The results suggest that having less than ten teeth is associated with sleeping less than four hours, or more than seven hours per night. Researchers write, “The finding that older adults with few teeth had both shorter and longer sleep durations indicates that these individuals may be suffering from obstructive sleep apnea (OSA).” Previous studies have linked OSA with conditions like stroke, diabetes, heart disease and even premature death. The finding suggests promoting dental health among older adults may help them to continue sleeping in a healthy manner.