Maxillary Sinus Augmentation without Grafting Material with Simultaneous Implant Installation: A Three-Dimensional Finite Element Analysis

Purpose: The study aims to provide a theoretical guidance of postmaxillary implant in the augmented sinus without grafting materials by establishing a three-dimensional model of this new implant restorative technique, evaluating failure risk of sinus augmentation without grafting materials of different alveolar ridge heights, and analyzing stress distribution of different healing stage. Materials and Methods: Seventeen three-dimensional finite element models of a posterior maxillary region with sinus mucosa and different elevation heights were constructed according to anatomical data of sinus area, and the standard implant model based on Nobel Biocare implant system were created via computer-aided design software. All materials were assumed to be isotropic and linearly elastic. Axial force of 150N was applied. The von Mises stress, stress distribution, and implant displacement were calculated with software. Results: With the height of the alveolar ridge reducing, the maximum von Mises stress of tissues and the displacement of the implant are on the rise, especially when the height of the bone is less than 7mm. When the height decreased to 4mm, the data may be doubled. After the stiff callus stage, the stress and displacement were close to the control model. Conclusion: For maxillary sinus augmentation without grafting material implant technique, the stress of different tissues and the displacement of the implant were not increased much when the height of alveolar ridge is more than 7mm. But if the alveolar bone height is less than 4mm, this implant technique is not suggested. Immediately loading is not suggested and the loading opportunity should be after the stiff callus stage at least to improve the success rate.