[Anatomical and radiographic study of the sinus floor distance from the alveolar crest in edentulous area of skulls].

The distance between the floor of the maxillary sinus and the alveolar crest in edentulous areas (where the 2nd bicuspid 1st and 2nd molars were previously located) were studied both anatomically and radiographically. The material consisted of 22 skulls in which 33 edentulous maxillary areas were found. Direct anatomical measurements were performed and measurements on periapical radiographs were made. The most important findings can be summarized as follows: 1. The mean distance from the alveolar crest to the floor of the sinus in locations corresponding to the 1st and 2nd molars and the 2nd bicuspid was 5.09 mm, 5.16 m.m. and 6.67 m.m. respectively. 2. Comparison of the anatomical measurements to those made on the radiographs proved that there are some differences but not statistically significant. These differences range between 0 to 5.5 m.m. for the 2nd bicuspid location, while for the 1st and 2nd molar locations they range between 0 to 2 mm.