sweet_tomato/shutterstock.com Researchers at Kyoto University Hospital have begun the first human trial of TRG-035, a drug meant to grow new teeth in people who are missing them. Humans keep a set of dormant tooth buds left over after the adult teeth come in, but a protein holds them switched off for life. The drug blocks that protein, which the researchers call "the body's molecular off-switch for tooth development." Thirty adult men, each short a tooth, have enrolled in the study . The discovery came from a genetic accident. Mice bred without the gene for that protein sprouted teeth they were never supposed to have. One shot of the antibody later produced working teeth in mice and ferrets, with no serious safety problems. No one in this trial is expected to grow a tooth. The first round, which began in late 2024 and was tracked for 11 months, tests only whether the drug is safe in people.…