Fig. 3From: Chronodentistry: the role & potential of molecular clocks in oral medicineCircadian clock hallmarks. A functional circadian clock has to include three characteristics: gene or protein production has to follow an oscillation pattern over approximately 24 h, the circadian rhythm is entrained by an environmental stimulus (zeitgeber [official technical term]) and continues with its oscillation pattern, even after taking away the stimulusBack to article page