Forsberg J
Department of Oral Radiology, School of Dentistry, University of Bergen, Norway.
Oral Surg Oral Med Oral Pathol. 1987 Sep;64(3):353-60. doi: 10.1016/0030-4220(87)90017-x.
The reproduction of a metal indicator simulating a root canal instrument at the apex of a tooth was examined as a function of paralleling, modified paralleling, and bisecting-angle radiographic techniques. Radiographs exposed according to the paralleling and modified paralleling principles demonstrated good correlation between the radiographic position of the metal indicator and its position on direct inspection. The bisecting-angle technique, either correctly or incorrectly angulated, produced the least accurate results. The apical location of the metal indicator was significantly more reliable with the paralleling principle than with the bisecting-angle technique (p less than 0.05).
研究了模拟根管器械的金属指示器在牙齿根尖处的再现情况，作为平行投照、改良平行投照和分角线投照技术的函数。根据平行投照和改良平行投照原则拍摄的X线片显示，金属指示器的X线片位置与其直接检查时的位置之间具有良好的相关性。分角线投照技术，无论角度正确与否，产生的结果最不准确。与分角线投照技术相比，平行投照原则下金属指示器的根尖定位明显更可靠（p小于0.05）。
