When taking clinical photographs, it is crucial that the angle of the image captured is correct when compared to the patient's natural postural position. Communicating this exact perspective is essential for the accurate transfer of information to the interdisciplinary team. If an error is introduced when composing the photograph, there may be significant errors made when treatment planning and ultimately in the result obtained.
To achieve the optimal esthetic and functional goals during planning and treatment, photographic communication of the three spatial planes is critical. The three planes are:
- Frontal (facial)
- Sagittal (profile)
Horizontal plane: level of camera to head
The patient should stand or sit in a straight back chair. Do not have them sit in the dental chair because it does not allow the patient to have a natural head posture. If standing, the shoulder blades will rest against a wall, but the back of their head should be away from the wall. If the head is against the wall, the head tips backward and is not posturally correct.
Often, portrait images are taken with the patient in a dental chair with the head tipped back. The photograph must then align the camera body sensor so it parallels the frontal plane and the lens is perpendicular to it. This can be challenging because of the interpretation of the angles that are created.
Frontal plane: facial plane
Taking a portrait image of the patient requires a natural head position (posture). When taking an intra or extra oral photograph, it is easy to rotate the lens in a way which does not capture an existing cant in the incisal and/or occlusal planes. A critical analysis of the interpupillary line relative to horizon is required.
The interpupillary line extends between the two pupils. Most of the time the interpupillary line is parallel to the horizon, but occasionally it is canted. If there is a cant in the interpupillary line relative to horizon, it must be captured precisely in the photograph.
To avoid composing your photos in a way that misrepresents or eliminates an existing cant, I suggest the following technique: When taking a photograph, I have the patient stare into horizon. The center of the lens is aligned with the incisal embrasure between the maxillary central incisors, with the barrel of the lens level with the horizontal plane.
Aligning the camera and the lens in this position will correctly capture any cant in the incisal and occlusal planes of the maxillary and mandibular teeth relative to the horizon.
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The sagittal plane is parallel to the sagittal suture, and divides the body into left and right. Align the camera lens along this plane, generally the midline of the face. The center of the lens is at the level of the embrasure between the maxillary central incisors.
For both frontal and sagittal portrait images, the photographer stands approximately six feet straight in front of the patient. The portrait images should be framed to include the top of the head and the upper part of the neck. The center of the photograph should be the embrasure between the maxillary central incisors.
I always try to level the viewfinder to horizon. For intra-oral photographs, I take straight-on images with the patient standing to help properly align the picture. The side and occlusal images are taken into a mirror, with the patient seated with the chair upright.
If everything is aligned precisely, there will be no need for computer corrections. If there is an error in the rotation of the head or camera body, a correction can be performed in Photoshop, Keynote, or PowerPoint. No other corrections can be made.