Manson-Hing L R
Oral Surg Oral Med Oral Pathol. 1980;49(1):86-9. doi: 10.1016/0030-4220(80)90036-5.
Intraoral radiographs were made via the bisecting-the-angle technique on patients of different ages, sexes, and races. The tooth-film angles for various areas of the mouth were measured and found to be close to 30 degrees for all areas of the mouth except the mandibular posterior regions. The study was conducted to assist in quick positioning of the x-ray beam in difficult cases.
通过分角线投照技术为不同年龄、性别和种族的患者拍摄口腔内X光片。测量口腔各个区域的牙齿与胶片的角度，发现除下颌后部区域外，口腔所有区域的角度均接近30度。开展这项研究是为了在困难病例中协助快速定位X射线束。
