Modified tooth stem cells (IMAGE) The University of Hong Kong Caption Tooth stem cells modified to mimic a cellular state similar to that under low oxygen (PHD2KD) gave rise to tooth pulp tissue with a significantly increased amount of blood vessels. Credit The University of Hong Kong Usage Restrictions N/A License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.