The critical size defect as an experimental model to test bone repair materials.

Accuracy and reproducibility are the hallmarks of the scientific method. Too frequently, the scientific method is abandoned and short circuited. The development and eventual clinical application of dental and medical materials and devices requires strict adherence to scientific methodology. The development of new bone repair materials is no exception. A reliable, convenient, and scientifically sound evaluation system is available for testing new bone repair materials. Animal models that fulfill stringent testing criteria and analytical methodology for assessment are described in this review. Experimental design, surgical protocols, tissue preparation for quantitative histology and x-rays, and biochemical assessments are reviewed.