Objectives To determine glucose transporter 1 (GLUT1) and runt‐related transcription factor 2 (RUNX2) expression during reparative dentinogenesis after pulpotomy with mineral trioxide aggregate (MTA) capping. Subjects and methods Eight‐week‐old male Wistar rats were used. Pulp of the upper left first molar was exposed and capped with MTA. The upper right first molar of the same animal was used as a control. After collecting molars at various time points, GLUT1, RUNX2 and mammalian target of rapamycin (MTOR) were examined by immunohistochemistry. mRNA levels of Slc2a1 (encoding GLUT1), Runx2, Nestin and Mtor were determined by real‐time PCR. Results Pulp exhibited progressive formation of reparative dentine lined with GLUT1‐ and MTOR‐immunoreactive odontoblast‐like cells at 5 days after pulpotomy. RUNX2 was detected in nuclei of most pulp tissue cells at day 5 after pulpotomy. Double immunofluorescence staining revealed GLUT1 immunoreactivity on odontoblast‐like cells positive for Nestin or RUNX2, 5 days after pulpotomy. Slc2a1, Runx2, Nestin and Mtor mRNA levels were significantly upregulated on days 3–5 after pulpotomy. Conclusions After rat molar pulpotomy, dental pulp induced formation of reparative dentine with colocalization of GLUT1 and Nestin or RUNX2. Moreover, mRNA levels of Slc2a1, Runx2, Nestin and Mtor were significantly upregulated in pulpotomized dental pulp.

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When regenerative endodontic procedures (REPs) are performed on immature teeth diagnosed with pulp necrosis and apical periodontitis, various healing patterns occur. Furthermore, infected immature teeth with endodontic disorders often exhibit some remnant pulp and apical tissue. Therefore, this study investigated the impact of remnant healthy or fully functional pulp and apical tissue on healing patterns after REPs. Simulated REPs were performed on non-infected immature rat molars with different amounts of remnant pulp and apical tissue. Healing patterns in these teeth were assessed after 28 days. Teeth with 0.81–0.91 mm of remnant pulp healed with pulp-like tissue, dentin, and osteodentin-like dentin-associated mineralized tissue (OSD-DAMT); teeth with 0.60–0.63 mm of remnant pulp healed with pulp-like tissue and OSD-DAMT; teeth with 0.13–0.43 mm of remnant pulp healed with periodontal ligament (PDL)-like tissue, OSD-DAMT, and cementum-like dentin-associated mineralized tissue (CEM-DAMT); and teeth with disorganization of pulp and apical tissues at 0.15–0.38 mm beyond the root apex healed with PDL-like tissue, CEM-DAMT, and intracanal bone (IB). Loss of Hertwig’s epithelial root sheath was observed with IB formation. These results showed that four distinct healing patterns occurred after REPs, depending on the preoperative amount of remnant healthy pulp and apical tissue.

Resin monomers and polymerisation initiators have been shown to be cytotoxic for pulp cells and to disturb odontoblast differentiation. This study aimed to compare the effect of a resin-modified calcium silicate cement (TheraCal LC; TC) and a resin-free calcium silicate cement (ProRoot MTA; PR) on pulpal healing after pulpotomy. Pulpotomy was performed on the maxillary first molars of 8-week-old rats using either PR or TC. After 1, 3, 7, 14 and 28 days, pulpal responses were assessed by micro-computed tomography, haematoxylin-eosin staining and immunostaining against CD68, which is a panmacrophage marker. The results showed that pulpotomy with TC induced persistent infiltration of inflammatory cells, including CD68-positive macrophages, and delayed the formation of reparative dentin as compared with that with PR, although both materials allowed pulpal healing over the long term. Therefore, resin-modified TC was not as biocompatible nor bioinductive as resin-free PR when applied on the healthy pulp of rat molars.