Upside down camera for oral cavity photography

Taking a picture of the oral cavity holding a digital camera in an upright position produces shadows that reduce picture quality (Fig. 2A and 2B supplemental). We propose to position the camera 30° anterior to the patient at the height of his mouth, placing it upside down to illuminate the oral cavity with the flash reaching from below (Fig. 1A and 1B). This simple technique improves oral cavity lighting as it reduces vertical and lateral shadows compared with a photograph taken with the flash in standard position. This effective solution is easy and quick to perform, avoiding delays and interruptions during medical consultations. It is useful for lesions localized in the buccal mucosa, the palate and the ventral surface of the tongue. Good results are achieved with both digital and smartphone cameras (Fig. 3 and 4 supplemental).以直立握持数码相机的方式拍摄口腔时，会产生阴影进而降低成像质量（补充图2A及2B）。我们提出一种改进方案：将相机置于患者口腔同高的前方30°位置，并倒置相机，使闪光灯从下方照亮口腔（补充图1A及1B）。相较于使用标准位置闪光灯拍摄的照片，该简易技术可减少垂直与侧向阴影，优化口腔照明效果。该解决方案操作简便快捷，可避免诊疗过程中的延误与中断，适用于颊黏膜、腭部及舌腹面的病灶拍摄。使用数码相机与智能手机均可获得良好成像效果（补充图3及4）。