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

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.

Evaluation of occlusion, trauma, and dental anomalies in African-American children of metropolitan Headstart programs.

493 African-American children between the ages of three and four years were examined for evaluation of molar occlusion with frequency of anterior and posterior crossbite, fractured and/or darkened teeth from trauma and dental anomalies in the primary dentition. Overall results from both age groups revealed 90% had a mesial step, 8% a flush and 2% a distal step molar occlusion. Crossbite, either anterior or posterior, occurred in 12% of all children examined. Posterior crossbite was seen in 7% and anterior crossbite in 5%. Anterior openbite was seen in 8% of the children. Trauma to the primary dentition occurred in 23% of the children, 16% as fractured and 7% as discolored teeth. The most frequently involved teeth were the maxillary primary central incisors. Fused primary teeth were observed in two children. There were no congenitally missing primary teeth and only one supernumerary maxillary primary lateral incisor was observed.

The polarized light microscopy and ultrastructure of Polynesian pigmented tooth enamel.

Transmitted and polarized light microscopy of unerupted and erupted teeth affected by a pigmented anomaly found in two geographically isolated Polynesian populations, the New Zealand Maori and the French Polynesian Marquesas Islander, showed similar histological characteristics. Mounted in water, the pigmented areas were positively birefringent and covered with a thin negatively birefringent surface layer 200-250 microns thick. Cervical areas were negatively birefringent. Transmission electron microscopy of argon-ion-beam thinned specimens of affected enamel revealed large voids, disruption in the packing of crystals and spacing at prism boundaries. In the surface layer of enamel from erupted and unerupted teeth, the intra- and interprismatic spaces were occluded by fine crystals or amorphous material. A well-defined prism structure and close crystal packing were found in cervical enamel. The ultrastructure of these pigmented enamels was similar to and consistent with a hypomaturation type of amelogenesis imperfecta.