Pathologic root migration secondary to vertical root fracture and full-coverage crowns: a report of 3 cases.

Occasionally, tooth fractures may demonstrate exaggerated pathologic root migration (PRM), often resulting in tooth loss. The early propagation of the root fracture may not be readily identifiable through clinical inspection and conventional radiographic imaging. Ultimately, increased root separation, isolated deep periodontal probing depth, and characteristic radiolucent changes may facilitate the diagnosis. This article describes 3 patients with unusual presentations of PRM in endodontically treated teeth restored with full-coverage crowns. One case illustrates the use of cone beam computed tomography for restorative assessment following root separation. Although it is efficacious to place crowns on most posterior endodontically treated teeth to maintain structural integrity, patients may remain at risk for catastrophic PRM and tooth loss. Timely extraction of teeth with hopeless PRM may minimize underlying bone resorption and the need for osseous regenerative procedures, ultimately improving the dental implant recipient site.

Extracellular Matrix Mediates BMP-2 in a Model of Temporomandibular Joint Osteoarthritis.

Temporomandibular joint (TMJ) osteoarthritis (OA) is a complex disease that affects both cartilage and subchondral bone. It is accompanied by loss of extracellular matrix (ECM) and may be controlled by bone morphogenetic protein-2 (BMP-2). We analyzed the effect of BMP-2 in both cartilage and subchondral bone in a TMJ-OA animal model that is deficient in biglycan (Bgn) and fibromodulin (Fmod) (Bgn-/-Fmod-/-). Whole mandibles were dissected from 3-week-old wild-type (WT) and Bgn-/-Fmod-/- mice and incubated with and without 250 µg/mL BMP-2 for 2 days using an explant culture system. Condyle growth was measured by microCT and the expression levels of cartilage and bone-related genes were analyzed using RT-PCR or by immunohistochemistry from condyles that contained an intact cartilage/subchondral bone interface. Osteoclast activity was estimated by tartrate-resistant acid phosphatase (TRAP) staining and by TRAP, Rankl, and Adamts4 mRNA expression levels. Our results showed that most parameters examined were slightly up-regulated in WT samples treated with BMP-2, and this up-regulation was significantly enhanced in the Bgn-/-Fmod-/- mice. The up-regulation of both catabolic and anabolic agents did not appear to positively affect the overall growth of Bgn-/-Fmod-/- condyles compared to WT controls. In summary, the up-regulation of both anabolic and catabolic genes in the WT and Bgn-/-Fmod-/- TMJs treated with BMP-2 suggests that BMP increases matrix turnover in the condyle, and, further, that Bgn and Fmod could have protective roles in regulating this process.