Background <p>Implant placement in the posterior maxilla is often complicated by anatomical limitations such as reduced alveolar bone volume, sinus pneumatization, sinus septa, and variations in ridge morphology. Accurate radiographic evaluation of these structures is therefore essential for predictable implant planning in the maxillary first molar region (MFMR). The aim of this study was to investigate the relationships between alveolar bone height (ABH), bucco-palatal crest thickness (CT), buccal concavity, sinus septa (SS), sinus pathology (SP), and demographic factors (age and gender), as well as jaw side and tooth presence in the MFMR, and to evaluate their relevance for implant planning.</p> Materials and methods <p>A total of 798 cone-beam computed tomography (CBCT) images from 399 individuals were retrospectively analyzed. ABH and CT were measured from the alveolar crest to a point 2&#xa0;mm coronal to the maxillary sinus membrane. The presence of concavity, SS, and SP was recorded using a binary (present/absent) classification.</p> Results <p>ABH and CT were significantly greater in dentate sites compared to edentulous sites (<i>p</i> &lt; 0.05). Age was significantly associated with CT, buccal concavity, SS, and SP (<i>p</i> &lt; 0.05). Tooth presence was significantly associated with concavity and SP, gender with SP, and jaw side with SS (<i>p</i> &lt; 0.05).</p> Conclusion <p>Anatomical variations in the MFMR are significantly influenced by demographic and site-related factors. Comprehensive CBCT-based evaluation of alveolar bone dimensions and sinus-related structures is essential for individualized and risk-aware implant planning in this region.</p>