Standardized in vivo model for studying novel regenerative approaches for multitissue bone-ligament interfaces.

The regeneration of the original structure and function of bone-ligament interfaces remains a major challenge in biomedical research. A preclinical model that maintains physiologic mechanical loads and controls for other external factors, such as microbial influence, is of great value for testing novel regenerative materials, provided that studies are performed by highly trained researchers with proper regard for animal welfare. The tooth root fenestration preclinical model is an ideal tool for hard tissue evaluation by micro-computed tomography, histological techniques and RNA analyses. The procedure starts with an extraoral incision lateral to the mandible and reflection of the masseter muscle. Superficial lateral mandibular bone is removed with standardized dimensions to expose the roots of the teeth and to eliminate periodontal ligament and cementum to expose the tooth dentin. The testing material can subsequently be applied to the defect and the flap can be repositioned and secured back in place. At specific time points, samples are collected and processed according to the subsequent analyses to be performed, which can include descriptive histology, histomorphometry, immunostaining, 3D bone imaging, electron microscopy, gene expression analyses and safety assessments.