Sir, we would like to highlight an ancient practice of teeth blackening that has resurfaced in the rural areas of Cambodia, Thailand and Vietnam. This trend was born from an antiquated way of preventing tooth decay. In ancient Japan, women painted a solution called kanemizuonto their teeth to protect the enamel and give the appearance of blackened teeth. The solution was made out of ferric acetate from iron filings mixed with vinegar and tannin from vegetables or tea. This custom was called ohaguro.1 These blackened teeth were deemed alluring and beautiful, and the practice continued through the centuries to demonstrate sexual maturity in women over the age of 18. It is said to have strengthened the teeth and protected a person from dental problems such as cavities and gum disease.

Ohaguro was banned by the Meiji government in 1870 and the art of dyeing one's teeth was almost forgotten.1 However, today, ohaguro is practised by many across Southeast Asian and Oceanic cultures, particularly among Austronesian, Austroasiatic and Kra-Dai-speaking peoples. Although the process is harmless to the teeth, it has an unpleasant appearance to it.2 Being used to white teeth as the standard, many visitors are shocked to see women with black teeth walking around. They assume that such people have poor oral hygiene, mistaking the dye for caries, while others, having realised that the blackening was done on purpose, wonder why people would 'disfigure' themselves in this way.