Here's a great piece on this phenomenon from Candida Moss, a professor at Notre Dame and one of my favorite public intellectuals on religion: Would you buy the Buddha's tooth?
In 2005, more than 60,000 donors poured $45 million and 270kg of gold into the construction of a Buddha Tooth Relic Temple in Chinatown in Singapore. A relic as precious as a tooth of the Buddha himself demanded lavish accommodations, and people were eager to contribute. According to the official website, the tooth was found by a Buddhist monk in 1980 when he was repairing the remains of a collapsed shrine in Myanmar.These are not new problems. But they also aren't old problems relegated to a "dark" or "superstitious" past.
But almost immediately after the temple complex opened in 2007, people began to ask questions. In a series of articles, Lianhe Zaobao pointed out that historical records suggest that there were only two extant teeth of the Buddha and both of those are already accounted for. Moreover, why had no one heard of this discovery?