X-ray opacity of the maxillary sinus were evaluated using a microdensitometer. The microdensitometer consisted of a luminescent supply, detector system and direct writing recorder. Blackning of the films affects the permeability of the light according to its degree. One can assess the cloudiness of the objected area from the recorded curve as a numerical value. Waters' views were used for the following analyses. A vertical line passing through the infraorbital foramen was assumed to get a continuous measurement of the opacity. The mean density between 1 cm and 2 cm above the foramen was used as the index of the orbita and that between 0.5 cm and 1.5 cm below the foramen as the index of the maxillary sinus. The ratio of these two indices were calculated to facilitate the comparison among subjects and within a subject. The data were firstly compared with macroscopic classification of four graduations. Secondly, comparisons were made before and after conservative treatments.
Densitometric evaluation of the films minimize errors caused by the radiographic technique and subjective variations among the examiners. It is also an excellent method to evaluate therapeutic effects within a subject.
