Objective: Report two cases of Odontogenic Maxillary Sinusitis (OMS), diagnosed exclusively by Cone Bean Computed Tomography (CBCT). Case Report 1: A 48 years-old woman referred diffuse pain across the face and upper left first molar (ULFM) with carious lesion. The panoramic X-Ray showed a periapical lesion with delimited limits in the ULFM and opacification of the left maxillary sinus (OPMS). Only in CBCT there were relationship between ULFM periapical lesion and the maxillary sinus through cortical rupture of the maxillary sinus floor, thickening the maxillary sinus mucosa (TMSM). The OMS was diagnosed as a periapical cyst invol- ving the ULFM. She was referred to endodontic treatment. Case Report 2: A 33 years-old man referred diffuse pain though the face and in upper right first molar (URFM). The panoramic X-Ray showed a bone rarefaction without limits and vertical bone loss ar...