Mimicking A Sinus Lift Procedure in a Murine Model

Objectives: Sinus lift surgeries, required prior to the placement of a maxillary dental implant in cases of severe alveolar bone loss, delay the implant placement for up to 6 months. Advances in stem cell biology offer a wide range of applications in dental surgery, all aimed at improving the healing process. Several animal species have been used as preclinical models for maxillary sinus lift surgeries, namely sheep and rabbits, but only mice are suitable for transgenic strains and could allow the study of molecular pathways of the healing processes. We postulated that despite anatomical discrepancies with a human maxillary sinus and the small size of the surgical site, mice would provide a suitable preclinical model for this procedure
Methods: After maxillary first molar extraction and successive socket healing, a mucosal tissue flap was elevated at the extraction site. Alveolar bone was drilled until the nasal cavity membrane was visible. Bone chips from either xenogenic origin (Bio-Oss, SUI) or syngeneic GFP mice were placed under the lifted membrane and the surgical site was closed using a collagenous membrane (Bio-Guide, SUI).
Results: Qualitative measures were used to analyze the outcomes of the surgeries. Microcomputed tomography analysis revealed proper bone chip placement above the maxillary molar extraction site. Staining with Movat’s pentachrome stain and aniline blue revealed active osteogenesis around the bone chips. Immunohistochemistry involving the GFP-labelled graft showed – for the first time – the relative contribution of the host to transplanted cells in bone healing and formation in the sinus.
Conclusions: Our data demonstrate that a murine model can be used to study sinus lift surgeries. Further testing of bone regenerative technologies using this model would provide new insights into therapeutics that could accelerate bone volume augmentation prior to implant surgery.