In this paper, using full-body CT images of elderly and advanced elderly Japanese cadavers, we measure maxillary and other paranasal sinus volumes in order to examine the effects of age, sex, presence or absence of maxillary molars, and other factors on changes to maxillary sinus volume. The research subjects consisted of 77 of 95 cadavers donated to the Kanagawa Dental University between 2012 and 2014, which average age was 82.6 ± 10 years (33 were male, average age 79.3 ± 8.3 years, and 44 were female, average age 85.1 ± 11.7 years). Sinus volume was measured from full-body CT images on the horizontal plane and computed using the 3D volume rendering software. The average maxillary sinus volume was 31.3 ± 13.2 cm3 (average value ± one standard deviation; hereafter the same), with values of 32.9 ± 13.2 cm3 (6.7 cm3 ～ 55.7 cm3) for males and 29.6 ± 12.5 cm3 (5.5 cm3 ～ 52.9 cm3) for females. In this report, we studied the effects of aging, sex, and state of remaining molars on changes to paranasal sinus volume in the maxillary sinus. These results give additional information about maxillary sinus volume of Japanese oldest-old peoples.