A patient complains of the alveolar process deformation of the left upper jaw. Objectively: the crown of the 25th tooth is destroyed with cariosity. X-ray image of the paranasal sinuses shows the left one to have veil-like shading with clear dome-shaped margin. X-ray image of the crown of the 25th tooth shows absence of the periodontal fissure at the palatal root apex. What is the most probable diagnosis?