パノラマ X 線写真における上顎洞像の拡大率について

Abstract

Panoramic radiography has recently been used for detection of maxillary sinus pathosis. But there are no studies on magnification of the maxillary sinue image on the panoramic radiograph. Therefore, the magnification factor of the maxillary sinus image on the panoramic radiograph in the different jaw positions was obtained experimentally. The results obtained are as follow : 1. When the dental arch was kept in the normal position and its occlusal plane was changed from -10°to +10°, the least variation of the vertical magnification factor was 1.20-1.22 in the central portion and 1.19-1.21 in the lateral portion of the anterior wall. 2. When the dental arch was kept in the normal position and its occlusal plane was changed from -10°to +10°, the least variation of the vertical magnification factor was 1.24-1.26 in the medial portion of the posterior wall. The variation of the vertical magnification was 1.19-1.23 in the central portion and 1.15-1.20 in the lateral portion. Then, in the panoramic radiography, when the dental arch was kept in the normal position, if the occlusal plane was changed slightly, the variation of the vertical magnification in the medial portion of the posterior wall is little. 3. When the dental arch was kept in the normal position and its occlusal plane was horizontal, the horizontal magnification factor was 1.16 in the medial portion of the anterior wall and 1.19 in the inferior medial portion. The horizontal magnification factor was 1.03 in the superior lateral portion of the anterior wall and 1.02 in the lower lateral portion. Then, in the panoramic radiography, the image in the medial portion of the anterior wall is magnified 13-17% horizontally than the image in the lateral portion. 4. When the dental arch was kept in the normal position and its occlusal plane was horizontal, the horizontal magnification factor was 0.54 in the superior medial portion of the posterior wall and 0.52 in the lower medial portion. The horizontal magnification factor was 0.45 in the superior lateral portion of the posterior wall and 0.40 in the lower lateral portion. Then, in the panoramic radiography, the image in the medial portion of the posterior wall is reduced 46-48% horizontally and is reduced 55-60% in the lateral portion.