Lee JS, et al. - Since the periodontal ligament (PDL) includes cells embedded in the extracellular matrix and is needed for periodontal healing upon tooth transplantation, researchers assessed the impacts of separate PDL matrix without cells on periodontal healing in this preclinical study. Mandibular premolars extracted from six beagle dogs were left untreated, decellularized, or surface planed. No significant changes were found when comparing untreated teeth with teeth having a decellularized PDL, and decellularized teeth exhibited a significant increase of new cementum vs surface planed teeth. Besides untreated PDL, decellularized PDL also partly promotes reattachment (especially cementogenesis) in pristine extraction sites but not in defect areas.