AIM: To assess the feasibility of using the mouse as an in vivo model for studying pulpal healing in response to restorative procedures. METHODOLOGY: Direct pulp capping on maxillary first molar teeth with mineral trioxide aggregate (MTA), overlaid with light-cured composite resin, was performed on nineteen 3-month-old mice. For control teeth, the composite resin was placed in direct contact with the pulp. Animals were killed at 3 days, 1 week, 2 weeks, 5 weeks and 11 weeks postoperatively. Extracted dental tissues were subsequently analysed by haematoxylin and eosin staining, immunohistochemistry for dentine sialophosphoprotein (DSPP) expression, scanning electronic microscopy and X-ray analysis to determine both pulpal response and dentine bridge formation. RESULTS: Of the 19 mice initially used, 16 were subsequently studied. Histological analyses of pulps directly exposed to MTA for up to 2 weeks demonstrated a distinct structural change in the extracellular matrix. By weeks 5 and 11, a dentine bridge was present in all MTA-treated specimens in which DSPP immunoreactivity was clearly apparent. Scanning electronic microscopy and X-ray analysis enabled confirmation of calcification of the dentine bridge, and demonstrated that it had a globular surface morphology as opposed to the tubular appearance associated with orthodentine. CONCLUSIONS: This is the first description of the utilization of a murine model for study of in vivo pulpal repair. This approach provides a novel opportunity to enable the use of genetically modified animals to explore cellular and molecular processes during reparative events.
AIM: To assess the feasibility of using the mouse as an in vivo model for studying pulpal healing in response to restorative procedures. METHODOLOGY: Direct pulp capping on maxillary first molar teeth with mineral trioxide aggregate (MTA), overlaid with light-cured composite resin, was performed on nineteen 3-month-old mice. For control teeth, the composite resin was placed in direct contact with the pulp. Animals were killed at 3 days, 1 week, 2 weeks, 5 weeks and 11 weeks postoperatively. Extracted dental tissues were subsequently analysed by haematoxylin and eosin staining, immunohistochemistry for dentine sialophosphoprotein (DSPP) expression, scanning electronic microscopy and X-ray analysis to determine both pulpal response and dentine bridge formation. RESULTS: Of the 19 mice initially used, 16 were subsequently studied. Histological analyses of pulps directly exposed to MTA for up to 2 weeks demonstrated a distinct structural change in the extracellular matrix. By weeks 5 and 11, a dentine bridge was present in all MTA-treated specimens in which DSPP immunoreactivity was clearly apparent. Scanning electronic microscopy and X-ray analysis enabled confirmation of calcification of the dentine bridge, and demonstrated that it had a globular surface morphology as opposed to the tubular appearance associated with orthodentine. CONCLUSIONS: This is the first description of the utilization of a murine model for study of in vivo pulpal repair. This approach provides a novel opportunity to enable the use of genetically modified animals to explore cellular and molecular processes during reparative events.
Authors: Praveen R Arany; Andrew Cho; Tristan D Hunt; Gursimran Sidhu; Kyungsup Shin; Eason Hahm; George X Huang; James Weaver; Aaron Chih-Hao Chen; Bonnie L Padwa; Michael R Hamblin; Mary Helen Barcellos-Hoff; Ashok B Kulkarni; David J Mooney Journal: Sci Transl Med Date: 2014-05-28 Impact factor: 17.956