DENTAL PHOTOGRAPHY 2.pdf

DENTAL PHOTOGRAPHY Photographic Equipment Dr. Gülşilay SAYAR, DDS,PhD Associate Professor Bahçeşehir University School of Dental Medicine Department of Orthodontics [email protected] References ESSENTIALS OF DENTAL PHOTOGRAPHY IRFAN AHMAD Photographic Equipment Photographic Equi...

DENTAL PHOTOGRAPHY Photographic Equipment Dr. Gülşilay SAYAR, DDS,PhD Associate Professor Bahçeşehir University School of Dental Medicine Department of Orthodontics [email protected] References ESSENTIALS OF DENTAL PHOTOGRAPHY IRFAN AHMAD Photographic Equipment Photographic Equipment The most frequently asked questions about dental photography are: ‘Which equipment do I need?’ ‘What is the cost?’ ‘How long will it take to learn?’ The aim of this lecture is to provide answers to these questions. Photographic Equipment Photography should be regarded as an integral part of daily clinical and photographic equipment as part of the dental armamentarium, no different to a dental handpiece. However, the common consensus is that a camera is an extraneous apparatus, exclusively reserved for specialists, or clinicians with a penchant for taking pictures. *Armemantarium: the equipment, methods and pharmaceuticals are used in medicine Photographic Equipment These are erroneous assumptions since photographic documenting is essential for diagnosis, treatment planning, treatment options, educating patients and staff, Communicating with colleagues, recording treatment sequences, assessing and monitoring outcomes, marketing, and serves as irrefutable evidence if litigation ensues. Photographic Equipment That dental photography is not solely for specific treatments such as elective cosmetic procedures, but a requisite for recording pathological conditions of the oral mucosa or even the tooth whitening. Photographic Equipment Similar to learning a particular clinical technique such as crown preparation or implant surgical procedures, there is a learning curve for mastering dental photography. The time required to learn basic photographic techniques is reduced with proper advice and guidance. Taking pictures is probably easier than restoring a Class I cavity, but does require a degree of patience and perseverance. A routine photographic session should take no more than 10 minutes of Clinical time; a small sacrifice compared to the innumerable benefits if offers. Photographic Equipment Cameras Before choosing a camera and the accompanying accessories, it is crucial to establish the basic requirements of dental photography. Dental photography is essentially divided into two types of picture: portraiture and macrophotography. Photographic Equipment Cameras Portraits are necessary for several disciplines and clinical scenarios such as orthodontics, prosthodontics, aesthetic/cosmetic dentistry, Facial enhancement procedures, external traumas to the dentition, or accidents involving soft tissue bruising, lacerations and fractures of the facial skeleton. Photographic Equipment Cameras Macrophotography encompasses both intra‐oral pictures of the oral environment consisting of the teeth and surrounding anatomy, and extra‐oral pictures of the dento‐facial composition and bench images of diagnostic casts or artificial prostheses/restorations. Therefore, it is essential to choose a camera and accessories that fulfill the requirements of both portraiture and macrophotography. Photographic Equipment The market is full with cameras offering countless functions, some superfluous, others essential, and deciphering which are useful or redundant is a challenging and annoying issue. It is important to ignore manufacturers’ hype and concentrate on salient specifications. Photographic Equipment . The type of camera systems point‐and‐shoot, compact, CCS (compact camera systems), EVIL (electronic viewfinder interchangeable lens), MILC (mirrorless interchangeable‐lens compacts), rangefinders, dSLR (digital single lens reflex) the smartphone (cellphone) Photographic Equipment Photography would not smartphone cameras. be complete without mentioning In recent years the quality of smartphone cameras has increased, and these devices are capable of delivering images that were once only possible with dedicated digital cameras. Many reputable camera manufacturers such as Leica. , Hasselblad. and Carl Zeiss. are collaborating with phone companies to develop cameras and accessories for mobile hardware. Photographic Equipment The main purpose of smartphone cameras is that they are designed for social photography. Hence, to use these units for medical/dental purposes, the in‐built cameras need to be calibrated and modified for macro use, which requires a degree of training. Smartphones are ideal for random shots showing patients’ particular oral problems, or sharing cursory images with dental technicians, but to take this a step further, training is essential. In the near future, mobile devices may evolve to be the standard for photo-documentation for many fields, including dentistry. Photographic Equipment Photographic Equipment In order to satisfy the requirements of dental photography and produce images rich in detail,vibrancy, nuances of colour, texture, form, conveying emotions, feelings and unparalleled quality, the only choice at present is a dSLR. Whilst other category of cameras can be tailored or adapted for dental use, the task is onerous, and probably not worth the frustration for the small cost saving that is often elusive. Photographic Equipment Having established that a dSLR is the ideal camera for dental applications, the next question is: which proprietary brand to choose? Mid‐range dSLRs from any major brands are almost identical in terms of features and the image quality they offer. Photographic Equipment A dSLR consists of a body containing the mechanics and electronics, or brain, of the camera. A camera body usually comes as a kit with a lens and other basic accessories. However, most lens that form a kit are often unsuitable for dental applications, it is advisable to purchase the body alone, or exchange the accompanying lens for one that is more suited for dental use. Photographic Equipment The primary features to look for in a camera body are the physical size of the sensor, megapixel count, colour depth, numerical white balance input, external flash synchronisation via a hot‐shoe with TTL (through‐the‐lens) metering, switchable manual focusing, sensor speed or ISO (International Standards Organisation) range, remote shutter release, tripod thread(s) and ease of sensor cleaning. Photographic Equipment The secondary features include exposure modes and metering, shutter speeds, sequential frames per second, colour space, dust and water spray sealing, anti‐fingerprint and anti‐scratch coating of the LCD (liquid crystal display) touch screen, RAW file formats, video capability, GPS (global positioning system), WiFi, storage media, interface for data transfer, built‐in photo‐editing software, build quality, size, weight and, of course, the price. There is no compromise of the mandatory primary features, the secondary features are desirable, but not necessary. Photographic Equipment Sensors The heart of a digital camera is the sensor, a solid‐state device composed of tiny photosensitive diodes called pixels, (abbreviation of ‘picture elements’). The pixels are stimulated by incoming light through‐the‐lens to create an electrical charge that is an analogue signal. The electrical signal is then converted by an analogue to digital converter (A–D converter) into a binary digital code, or data, for creating the image. Photographic Equipment Sensors The pixels are colour blind, only capable of registering black and white, or brightness and darkness and require some types of filters toproduce colour images using the additive red, green and blue (RGB) colour system. Photographic Equipment Sensors The additive RGB colour system represents the three primary colours RGB, which collectively produce white when mixed together. This is in contrast to the substrative colour system: cyan, magenta, yellow (CMY). The colour filter system used by manufacturers for adding colour iseither the mosaic Bayer pattern, or the Fovean X3. colour filters. Photographic Equipment The key issue is the physical size (or dimensions) of a sensor: the larger the sensor, the better the image quality, irrespective of the pixel count. Photographic Equipment Photographic Equipment Photographic Equipment Photographic Equipment Photographic Equipment Photographic Equipment Photographic Equipment Resolution The resolution of an image is complex, depending on many variables, including the resolving power of the lens, sensor size, number and size of pixels, bit depth (range of colours), dynamic range (degree of contrast), signal to noise ratio (amount of ‘noise’ or graininess in an image), method of in‐camera analogue to digital conversion, file format, subsequent post‐capture editing with computer software, circle of confusion (distant from which an image is viewed) and the display media (monitor, projector, printing). Photographic Equipment Photographic Equipment Photographic Equipment The resolution of the human eye varies from 324 megapixels (90 degree angle of vision) to 576 megapixels (120 degree angle of vision), which is far beyond any contemporary digital camera sensor. The number of pixels determines the size of an image, not its ultimate resolution. However, a large pixel count is significant if the resolution is not to be compromised when part of an image is magnified or cropped. Hence, the resultant image quality depends on the number of megapixels (MP) and the physical size of the sensor Photographic Equipment A fullframe sensor with a pixel count of 20 MP yields a higher resolution than a smaller‐sized sensor with the same or greater number of pixels. This is because the larger pixels found on large‐sized sensors are capable of gathering more detail than the smaller pixels on small‐sized sensors. A small sensor with a large pixel count, often found in compact cameras, produces inferior quality images compared to a larger sensor with fewer pixels in a dSLR. Photographic Equipment Another factor to enquire about is the presence or absence of an anti‐alias filter on the sensor. Newer cameras without anti‐alias filters offer superior resolution and therefore better image quality. Photographic Equipment Sensor Speed or ISO The sensitivity of the sensor to light is represented by its ISO number. The ISO scale determines the intensity of light that is necessary for correct exposure; a lower ISO number requires more light, whilst a higher ISO number less light. Photographic Equipment Sensor Speed or ISO Although higher ISO values have the benefit of taking pictures in low lighting conditions, the drawback is that the pictures are more grainy (with increased ‘noise’) and consequently with inferior resolution. As a general guide, an ISO value of 50–100 will produce insignificant noise but requires brighter illumination, whilst the ideal for dental use is between ISO 100 and ISO 200, and certainly should not exceed ISO 400. Photographic Equipment Photographic Equipment Sensor Cleaning Dust particles enter the camera at the junction where the lens is mounted onto the camera body, and also by the movement of the internal mirror (if any) within the camera. This is particularly significant when changing lenses or focusing screens, which should be performed in a dust‐free environment, preferably with appropriate vacuum suction. Photographic Equipment Sensor Cleaning The dust particles are a nuisance, adhering to the sensor surface and appearing as black or white specks on an image, especially noticeable with light backgrounds such as teeth. Although these blemishes can be erased with software during the editing stage, the process is tedious, time‐consuming and best prevented at the outset. Photographic Equipment Sensor Cleaning Sensors are difficult to access and clean manually, requiring a degree of dexterity to prevent inadvertent damage to the most delicate and expensive part of the camera body. Many proprietary sensor cleaning kits are available that provide mitigating irreversible damage to the sensors. Many cameras have built‐in sensor‐cleaning mechanisms that minimise dust accumulation and facilitate its removal. It is important to enquire about ease of sensor cleaning, or built‐in cleaning systems, when purchasing a camera body. Photographic Equipment Photographic Equipment Photographic Equipment Colour (Bit) Depth The colour, or bit depth, is a measure of the number of colours that can be captured by a sensor. It is expressed as bits/channel or bits/colour of the three photographic additive primary colours, red, green and blue. The advantage of having a larger bit depth is reducing degradation of image quality. Photographic Equipment Photographic Equipment White Balance Unlike our brains, cameras do not possess colour adaptation, and have to be ‘told’ about the colour temperature of the illumination, a process known as setting or calibrating the white balance. Most cameras have pre‐set automatic white balance (AWB) options that signify the quality, or colour temperature of the light, e.g. natural daylight of 6500 K, or indoor tungsten illumination of 3200 K. Photographic Equipment White Balance Photographic daylight is 5500 K because at this colour temperature all the three photographic primary colours (RGB) are present in equal proportions. This is an important issue for dental images the colour accuracy needs to be precise, without colour casts, for faithfully reproducing the actual colour of the soft and hard tissues. Photographic Equipment White Balance This allows distinguishing between health and pathological changes, as well as matching the shade of artificial restorations to natural teeth. Most dental photography uses artificial [flash] lighting, and it is important to ensure that the white balance on the camera is either set to AWB, or preferably input manually numerically to 5500 K. Photographic Equipment Focusing Almost every camera these days has auto‐focus (AF) as standard, for macrophotography, especially in the restricted confines of the oral cavity, AF often malfunctions. This is due to incessant patient or operator micro‐movements, and extreme light thresholds of the highly reflective surfaces of teeth with the dark posterior regions of the mouth, which additively confuses the automatic focusing mechanism. Photographic Equipment Focusing The ability to switch to manual focus (MF) is a prerequisite to compensate for the unique conditions of the oral environment. The usual method for ensuring sharply focused dental images is either using a mechanical focusing stage, or moving hand‐held cameras backwards and forwards until focusing is accomplished. Another advantage of MF is that it allows pre‐set magnifications (e.g. 1 : 1 or 1 : 2) for consistent scaling of images that is useful for comparisons, whereas with AF, the magnification perpetually changes according to the distance of the subject from the lens. Photographic Equipment External Flash There are two types of external flash lighting necessary for dental applications: compact flashes and studio flashes or strobes. Compact flashes are mainly used for macrophotography and require a hot‐shoe contact, usually found on top of the camera, to access the electronics of the camera. Photographic Equipment Remote Shutter Release The camera shutter is usually released by pressing a button on the camera body. This is satisfactory for the majority of dental images, but for certain treatment modalities that require photographs from various angles of view such as aesthetic dentistry, or surgical procedures where cross‐infection control is paramount, it is necessary to mount the camera onto a tripod and delegate this task to another member of the dental team. Several options are available, including wireless, foot control and smartphone apps, which are operated by an ancillary not directly involved with the treatment. Photographic Equipment Lenses The technical requirements of a lens for dental photography is that it serves a dual‐purpose, first for portraiture and second for close‐up or macrophotography. The ideal lens for portraiture is around 100 mm focal length, and for macrophotography is a macro facility for achieving a 1 : 1 or 1 : 2 magnification. A 1 : 1 magnification ratio means that the image recorded on the sensor is the same size as the object, whilst a 1 : 2 magnification means that the captured image is half the size of the object. Photographic Equipment Lenses Macro lenses are either available as fixed focal lengths, called prime lenses, or zooms with variable focal lengths. It is recommended to use prime lenses, rather than zooms, which are usually impractical for dental photography. Fixed focal length macro lenses greater or less than 100 mm are unsuitable for the following reasons. To achieve a 1 : 1 magnification with a 50 mm macro lens requires moving the camera extremely close to the subject, which may be intimidating for the patient Photographic Equipment Lighting There are two types of lights required for dental photography: compact and studio flashes. Many cameras have built‐in flashes that pop‐up when the lighting conditions are less than optimal. This is satisfactory for general photography but ill‐advised for macrophotography. The compact flashes are further sub‐divided into ring flash (ring‐light), compact off‐the camera bilateral (bi‐directional or twin‐light) flashes, or a single unit consisting of both ring and twin‐lights. Photographic Equipment Lighting Compact flashes, also known as hot-shoe flashes, connect directly onto the hot‐shoe of the camera body. Their intensities are measured in guide numbers at ISO 100, the higher the guide number, the brighter the light output. Typical compact flashes have a guide number ranging from 20 to 50 (100 ISO metre) or 65 to 165 (100 ISO feet). Photographic Equipment Lighting For dental use, a guide number of ISO 30 (metre) is more than adequate. All electronic flashes serve a dual purpose, first to provide sufficient illumination for correct exposure, and second, to ‘freeze’ the object being photographed. Photographic Equipment Photographic Equipment Photographic Equipment For anterior teeth, or for restorations where aesthetics are of paramount concern, ring flashes are not recommended since the uniform burst of light obliterates fine detail, translucency, surface texture, topography and subtle colour transitions and nuances within teeth or artificial restorations. Photographic Equipment To overcome the shortcoming of ring flashes, compact bi‐directional or bilateral flashes offer lighting that sculpts the object giving it a three‐dimensional appearance with highlights and shadows, allowing visibility of enamel characterisations such as mamelons, cracks, staining, translucency, restorative marginal defects. Photographic Equipment By manipulating the light source reveals colour nuances and depth of the underlying dentine strata, which is essential for mimicking these characteristics in indirect prostheses. The intensity of individual flashes can be muted, or turned off, to enhance highlights or shadows that are ideal for capturing micro and macromorphology. Photographic Equipment Photographic Equipment Three are two varieties of lateral flashes. The first type attaches onto the front of the lens by an adapter and has two projecting flashes, which can be positioned right, left, top, bottom or anywhere in between. The negative aspect of these flashes is their proximity to the teeth, and depending on the guide number, the flash burst can be harsh, similar to ring flashes that obliterate fine detail. To circumvent this undesirable effect, the second type of lateral flashes are mounted with a bracket, or flash extension arms, beneath the camera and positioned behind the lens. Photographic Equipment The second type of lighting is for dental portraiture, which may be hot lights, cool lights or flashes. The first two types, hot and cool lights, offer continuous illumination that is suitable for video but unsuitable for still photography. The preferred types of lights for portraits is studio flashes. Photographic Equipment If the flashes are intended only for head‐shots of a single person, two 120 W/s flashes are sufficient. However, if pictures of small groups, bigger objects in larger spaces, or creative lighting with light‐modifying attachments is required, two or more >300 W/s flashes are recommended. Photographic Equipment Supports Monopods, tripods, jibs, cranes, booms, cages, clamps, brackets, steady cams, rails, slides, dollies and suction pads. To simplify matters, for dental photography, a tripod with a dolly (wheels), and a four‐way focusing rail (stage) for fine focusing is all that is necessary. Photographic Equipment Photographic Equipment Photographic Equipment Other Photographic Items Rechargeable batteries, a multi‐card reader for transferring images to a computer, UV bulbs for visualising fluorescence of natural teeth and artificial prostheses. A polarising filter is helpful for analysing shade by eliminating specular reflections (glare) off the enamel surface. Digital photography requires a computer and processing software, dealing with editing, exporting and managing images. Thank you...