Black teeth: beauty or caries prevention? Practice and beliefs of the Kammu people.

Abstract –  Background:  To be beautiful and caries-free, Kammu women in Laos and Vietnam habitually paint their teeth black. Although this practice existed for many generations, it is now known only among the elderly. Objectives:  To describe how the tooth-blackening procedure is performed and to test the black stain for possible antimicrobial effects in laboratory experiments. Methods:  Information on how to blacken teeth was obtained by interviewing groups of elderly Kammu people living in different villages in Laos and Vietnam. Water extracts of the stain were placed in wells in agar plates and the plates incubated with Streptococcus mutans or S. sobrinus. The stain was also let such that it covered half of the strip test-side of the Dentocult SM® Strip Mutans test kit and incubated with saliva from five persons known to carry mutans streptococci in their saliva. Results:  Interviews revealed that three plants were commonly used: Dracontomelon dao nuts (DD nuts), Cratoxylum formosum (CF) wood or Croton cascarilloides (CC) wood. The parts (nut, wood) were burned and soot collected on metal plates. The fresh soot, which had a viscous consistency, was applied to teeth with the index finger. Extracts of soot of the DD nuts had no effect on the streptococci on agar plates but inhibited the growth of salivary mutans streptococci on strips. Controls using soot from birch tree (Betula pendula) had no effect. Conclusions:  The procedure was simple and resulted in black, beautiful (?) teeth. The soot of DD nuts effectively inhibited growth of salivary mutans streptococci in in vitro experiments.