January 3, 2007
When deciding whether to place a crown over a patient’s damaged tooth, one of the dentist’s first - if not, the first - considerations is the condition of the underlying tooth root. Is it sound enough structurally to support the crown? In too many cases, the answer is no, and dentists have longed for effective strategies to regenerate or even regrow the root. In the December 20 issue of the online journal PLOS One, NIDCR grantees report early success using stem cells to engineer a replacement root/periodontal complex that in studies with mini pigs was capable of supporting a porcelain crown and provide normal tooth function. In the study, the scientists extracted developing human wisdom teeth and harvested the stem cells from their root-forming apical papilla. They found that the apical papilla contains a new stem cell population, which they called SCAP (for “stem cells from root apical papilla”), had tremendous capacity to differentiate into dentin-producing cells present in the tooth root. Following up on this lead, the researchers and their colleagues transplanted a scaffold carrier containing SCAP and human periodontal ligament stem cells (PDLSCs) into mini pigs and found the combination produced cementum and collagenous Sharpey’s fibers of the periodontal ligament, an indication the root/periodontal complex could be generated. To further test this finding, the researchers isolated SCAP from the mini pig and transplanted a root-shaped scaffold containing SCAP/PDLSCs into the mandible of the mini pig. After suturing the wound and waiting three months, they implanted a porcelain crown into the root/periodontal structure. They found after four weeks that their porcelain crown on the root/periodontal complex was nearly as strong as the original tooth. The scientists concluded, “These findings suggest the feasibility of using a combination of autologous SCAP/PDLSCs in conjunction with artificial dental crowns for functional tooth regeneration."