We may still not have jetpacks or flying cars, but it looks like the 21st century might be about to get a bit more futuristic. As Discovery News reports, a study published in the ACS Nano journal is offering some fairly convincing evidence that a new type of hormone gel could potentially regenerate teeth and eliminate the need for fillings in at least some cases. According to the French scientists behind it, the gel has already managed to make cavities in mice "disappear" after only a month, and the peptide used in the gel, MSH, has also previously been shown to encourage bone regeneration. Of course, it will be a little while yet before your dentist puts down the drill -- the researchers say there still needs to be "several years" of clinical trials, and note that it likely won't replace fillings altogether (or prevent them).