Contribution of Bone Marrow-derived Cells to Reparative Dentinogenesis Using Bone Marrow Transplantation Model.

INTRODUCTION: The aim of this study was to analyze the contribution of bone marrow-derived cells (BMDCs) to reparative dentinogenesis using bone marrow transplantation (BMT) and pulp capping as an in vivo model. METHODS: A chimeric mouse model was created through the injection of BMDCs expressing green fluorescent protein (GFP+ BMDCs) from C57BL/6 GFP+ transgenic donor mice into irradiated C57BL/6 wild-type recipient mice (GFP- mice). These GFP- chimeric mice (containing transplanted GFP+ BMDCs) were subjected to microscopic pulp exposure and capping with white mineral trioxide aggregate (n = 18) or Biodentine (Septodont, St Maur-des-Fossés, France) (n = 18) in the maxillary first molar. Maxillary arches from GFP- chimeric mice (with the capped tooth) were isolated and histologically processed 5 (n = 9) and 7 (n = 9) weeks after BMT. Confocal laser microscopy and immunohistochemical analysis were performed to assess the presence of GFP+ BMDCs and the expression of dentin sialoprotein, an odontoblast marker, for those cells contributing to reparative dentinogenesis in the dental pulp. RESULTS: Confocal laser microscopic analyses evidenced the presence of GFP+ BMDCs in close association with reparative dentin synthesized at the site of pulp exposure in GFP- mice 5 and 7 weeks after BMT. Immunohistochemical analysis revealed that GFP+ BMDCs in close association with reparative dentin expressed DSP, suggesting the contribution of nonresident GFP+ BMDCs to reparative dentinogenesis. CONCLUSIONS: These data suggest the presence of nonresident BMDCs in reparative dentinogenesis and its contribution to dental pulp regeneration in the pulp healing process.

Root Anatomy and Canal Configuration of Maxillary Molars in a Brazilian Subpopulation: A 125-µm Cone-Beam Computed Tomographic Study.

OBJECTIVE: Knowledge of internal anatomy of the teeth is of great importance in endodontics, leading to success in root canal therapy (RCT). The aim of this study was to assess the root anatomy and canal configuration of maxillary molars in a Brazilian subpopulation using tomographic images using a voxel size of 125 µm. MATERIALS AND METHODS: This in vivo retrospective study assessed 651 cone-beam computed tomographic scans from 328 maxillary first molars and 323 maxillary second molars. The images were assessed by two endodontists and an oral radiologist. Only permanent molars with fully developed roots and with no signs of RCT were included. RESULTS: Maxillary first and second molars presented three separated roots in 99.39 and 90.09% of the cases, respectively. The presence of mesiolingual canals in the mesiobuccal roots was 64.22% for maxillary first molars and 33.56% for maxillary second molars. Distobuccal canals in the maxillary first and second molars presented Vertucci's Type I configuration in 99.39 and 99.66%, respectively, and palatal canals in the maxillary first and second molars presented Vertucci's Type I configuration in 99.69 and 99.68%, respectively. Maxillary second molars were more subjected to anatomical variations than first molars. Female patients presented higher prevalence of mesiolingual canals in the maxillary second molars. CONCLUSIONS: The most prevalent morphology in the maxillary first and second molars was three root canals. The presence of only one or two roots is more likely to occur in the maxillary second molars than in the maxillary first molars. Mesiolingual canals in mesiobuccal roots are more frequent in the maxillary first molars than in the maxillary second molars, and the occurrence of two distobuccal or two palatal canals is rare.