Sinus Pneumatization

This research aims to investigate the influence of alveolar ridge preservation, after extraction of maxillary posterior teeth, on the potential need of sinus floor augmentation procedures (that include lateral or crestal sinus augmentations). From peri-apical radiographs, maxillary posterior teeth will be divided into 4 groups according to the relationship of their apexes with the sinus. Then, the patients will be divided into 2 sub-groups: unassisted socket healing (only extraction) and ARP group (extraction + ARP) and their CBCT scans before implant placement will be collected. The CBCT scans should be at least 4 months post-extraction and ARP. Depending on the residual bone height, patients will be divided into 3 categories, according to the ABC classification: 1. In need of lateral sinus floor augmentation 2. In need of crestal sinus floor augmentation 3. No need for sinus floor augmentation, therefore, implant placement. These divisions will be conducted, according to: \- The residual bone height (RBH) which is the height in mm from the alveolar ridge crest to the lowest point of the maxillary sinus floor. The results of the proposed hypothesis are verified and interpreted after statistical analysis.