Classifying Maxillary Sinuses of Polish Patients for Sinus Lift: A Pilot Study.

To date, there is no systematic anatomical classification available that could help clinicians in choosing between the lateral and palatal approach in sinus lift procedures. The aim was to provide a simple-to-use and memorable classification of the maxillary sinus concerning the thickness of lateral and palatal walls to facilitate the most adequate choice for the window location during direct sinus floor elevation. Cone beam computed tomography scans were consecutively obtained for 200 maxillary sinuses of patients needing dental implant placement with potential maxillary sinus augmentation. The thickness and height of the alveolar bone of the lateral and palatal walls of the maxillary sinuses were assessed. Four variants were distinguished. Class 0: an adequate sub-sinus residual bone height; without the need for sinus floor augmentation. Classes 1-3 had a reduced sub-sinus residual bone height. Class 1: a thinner lateral than palatal sinus wall. Class 2 (the most frequent; 49%): the comparable thickness of both walls in which either lateral, palatal, or crestal window osteotomies can be applied. Class 3 (the least frequent; 3%): a thinner palatal sinus wall in comparison to the lateral wall. The presented anatomical classification simplifies the decision-making process of choosing the most adequate window location and osteotomy technique.