A method for producing experimental simple vertical root fractures in dog teeth

Vertical root fractures present difficult diagnostic problems and have poor prognoses. Treatment of root fractures consists of osseous recontouring, hemisection, and root amputation or sealing medicaments into the root canal in an effort to promote defect calcification. Dogs are often used as models for root fracture studies; however, production of simple vertical fractures has been inconsistent with high rates (18 to 65%) of undesired fragmented fractures. A technique to reproducibly create simple vertical fractures with minimal trauma and low fragmentation is described. Selected posterior dog teeth were endodontically instrumented. A 60-degree beveled tip conical wedge was controllable driven apically to cause fracture. The teeth were then medicated with experimental compounds and sealed with glass ionomer cement. After 8 wk, the animals were killed and the mandibles and maxillae dissected free and serially sectioned. Light microscopic examination revealed that most of the teeth fractured (93%) were the simple vertical type.