Lose an adult tooth, and you’re left with limited options that typically involve titanium implants or plastic dentures. But scientists are working on an alternative: lab-grown human teeth that could one day replace damaged ones.

Pamela Yelick and Weibo Zhang at Tufts University School of Dental Medicine in Boston have grown a mixture of pig and human tooth cells in pieces of pig teeth to create bioengineered structures that resemble real human teeth.

The toothlike structures represent a step toward bioengineered replacements for dental implants, say researchers behind the work.