A 3D model of the plicidentine of Ichthyostega, a Devonian stem tetrapod, was developed using a synchrotron X-ray scan of a maxillary tooth, and the program VGstudio. From the model, the folding pattern of the tooth could be determined. Ichthyostega showed a labyrinthodont dentition. In the cervical root. Acellular cementum was found, and possibly also cellular cementum, making it one of a few cases of cementum outside of crown amniotes, and the earliest known case of cementum among tetrapods, strengthening the hypothesis that cementum cannot be considered an exclusive amniote tissue. The folding pattern where cementum was present was markedly different to the apical root. In the basal root, the folds were more complex and penetrated by alveolar bone likely acting as the main form of tooth attachment. The function of plicidentine in Ichthyostega is concluded to be mainly acting in tooth attachment, however the folds expand far into the crown of the tooth which is not attached to any tissues. Weather this stretch of plicidentine have another function, such as related to feeding, could not be determined in this study. The developmental mechanism of folding could not be entirely determined; although based on the 3D model and the scan, it appears that the folds form independently and not one fold separating into several. Based on the morphology of the tooth and presence of attachment tissues a theoretical developmental model was proposed, which suggest that HERS (Hertwig’s epithelial root sheath) fragments during tooth development). However that the basal root grow past the covering of HERS and the basal folds form without guidance of epithelium.