A Gingival Regeneration Evaluation System Using a Rodent Model

ABSTRACT Aim This study aimed to create an objective assessment system for evaluating gingival tissue generated in a rat model using a representative free gingival graft (FGG). Methods A gingival defect (2 × 2 mm) created on the mandibular anterior teeth of rats was evaluated for its application as a gingival recession model after 4 weeks. Using this model, we investigated the validity of the method for evaluating gingival reconstruction at FGG site. Gingival margin heights of normal and transplanted gingiva were compared, and gingival pockets were visualized using computed tomography (CT). Objective color differences between normal gingiva and FGG site were evaluated up to 4 weeks over time. Results The surgical procedure was safely performed using tracheotomy airway management and a mouth opener. Gingival recession was evident 4 weeks after its creation. FGG implantation provided root coverage by macroscopic findings. Gingival pockets were detected in rats using CT imaging with contrast agents for the first time. Pockets at the FGG implantation site were deeper and wider than normal gingival pockets. Differences in color between normal gingiva and the FGG site were associated with vascular volume, melanocyte density, and epithelial keratinization thickness. Furthermore, blood flow was low, and melanin dots were abundant and diverse, with varying thicknesses in the keratin layer at the FGG site. Conclusion The findings of this assessment system reflect FGG reviews in humans. The gingival recession model and multidirectional comprehensive evaluation methods used in this study may contribute to developing new gingival reconstruction techniques.