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Texts Authored by Harry Albers, DDS
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(Girrbach/Jensen: 800-243-2000): These articulators have an easy to use face bow and transfer stand to send records to the laboratory. The system is very versatile. They offer non-arcon (#AM, AP, AR) and arcon articulators (NK, TK, TR) which are available with average value (NK, AM), semi-adjustable (TK, AP), and fully adjustable (TR, AP). Contact Ann Pellegrini: firstname.lastname@example.org.
Air Abrasion - Basic Principles:
Air abrasion devices are high energy sandblasting tooth cutting systems. It is the high energy of these particles which permits them to cut much faster and more precisely than traditional sandblasters. The cutting path of these devices is 100-1000 times smaller than their sandblaster counterparts. The cutting beam diameter averages about 300µm, but they can be made as small as 100µm. This is a unique technology. In December of 1982, the FDA approved the sale of newly designed air abrasion devices. Only in recent times have devices of this type reemerged into the dental profession.
Present day air abrasion devices are considerably more sophisticated and precise than earlier units. New metering systems have been developed to control the flow of abrasive particles. Many units have cutting beams as narrow as 500 microns. By increasing the beam working distance this beam can be increased to over 1 mm. Many new air abrasion devices are the size of a breadbox and weigh less than 40 lbs. Smaller, lighter, and more powerful units are under development. Present day technology offers the clinician considerable control of the particle beam as well as a pulsing feature which can double their efficiency.
Air Abrasion - Advantages and Disadvantages:
These devices cut tooth structure, especially enamel, with a precise, rapid beam of particles. There is less heat, pressure, and vibration. On enamel these devices produce considerably less crazing.
Their advantages include: 1) cleans pits and fissures with ease, 2) provides a clean surface for bonding to dental materials in the mouth, 3) less need for anesthesia. One study of surveyed patients showed that 90% of these patients reported little or no discomfort after having teeth restored with this procedure.
Their disadvantages include: 1) loss of tactile sense, 2) large size of many units, 3) high cost, 4) possible gingival tissue hemorrhage, 4) will not cut caries, 5) anesthesia is required in dentin, 6) will not cut metal and 7) noisy suction system used to clear the air of particles.
Air Abrasion Equipment:
There are many units on the market. Most vary in their speed of cutting and size of unit. All units remove enamel. The features or each unit should be determined by the dentist. Popular air abrasion units include
Prepstart air abrasion cavity system
is a highly recommended product. One of the most useful devices available for caries detection. The DIAGNOdent is a laser system that utilizes laser light of a defined wavelength to help detect and quantify demineralized tooth substances without x-ray exposure.
Curing Units - Halogen:
Recently more powerful curing lamps have been introduced. The typical lamp has a Power Density (PD) output of about 400 milliWatts/cm2. Newer lights have Maximum Power Densities (MPD) outputs of 600, 800 and even more. Many allow you to control the output of the unit. Composite Curing is based on energy which is measured in milliwatts per second. This unit of measure is called a joule. Curing energy is power density over time. Thus if you double the power density you can use half of the curing time and get the same curing energy. However, higher power densities result in more marginal stress which could result in more leakage and cuspal strain. Thus, many newer curing lamps have curing cycles which use different energies to reduce these unwanted side effects. The
(ESPE) have combined many of those feaures into one unit. The
(Bisco) has a pulse curing mode.
Curing Units - Arc and Laser:
Recently Arc and Laser Curing Lamps have being introduced. These emitted a narrow range of wavelengths of light (referred to as the band width). Today's composites often contain multiple initiators used to improve the physical properties of a composite and require a wider range of wavelengths to activate all of them. Thus, today's composites need a wide band width.
If too much curing light energy is placed into a composite (as with Arc and Laser lamps) the material forms smaller polymer chains, shrinks more, and results in a more brittle material. With present day materials, higher amounts of energy at narrow bandwidths are undesirable in resin curing. Thus, Arc and Laser Curing lamps are NOT recommended. Better result are achieved with conventional curing lamps with wide band widths (400-500 nm) and outputs of about 400-800 milliwatts per centimeter squared.
Improvements in composite restorations can also be made if the light is held away from the tooth and slowly brought to the surface within the first 5 seconds of curing. This is called
and is though to result in longer polymer chains, less shrinkage, and a more durable restoration. The total curing should be about 20-40 seconds, depending on the shade. Darker shades require more time.
Curing Light Tester:
A device for testing the effectiveness (the amount of 450-500 nm. light) of a curing unit. A reading of over 400 µW/cm2 indicates good function while a reading of under 200 indicates insufficient blue light. A poor reading means that the bulb, filter, or light should be replaced. Many newer curing lights have radiometers built into the units. Higher readings mean that the curing time can be reduced to proportionately. Curing Radiometer, Model 100 (Demetron) is a very nice hand held curing light tester which does not require a battery. Presently there are about a half dozen new radiometers on the market. Some are built into curing lights. All Curing Lights should be checked each month for adequate blue light output:
Parrallel Cutting Device:
by Weissman Technology (800-323-3136, 212 481-1010): A sophisticated device that allows the dentist to cut parallel preparations. Ideally the line of draw is set up on a model and transferred it to the patient. Once the tray is positioned in the mouth with bite registration material (it is relined after being attached to the model) it maintains the handpiece in a preset parallel position. Although the set up time has a learning cure, this device is extremely useful in cutting bonded bridge retainers.
Photography - Polaroid:
Macro 5 SLR (Polaroid) is made for dental use and has 5 different magnifications. It is light weight and easy to use. However, the image qualtiy and color saturation are marginal. Usefully mostly for patient viewing. CU-5 (Polaroid-discontinued) uses 669 film which has good color and sharpness. Each of three magnifications requires that adaptors on the camera be changed. The metal or plastic 2X framer works well for a smile (6 tooth) image. It has a heavy power pack and is awkward to use. However, useful for sending shade information to the laboratory.
Photography - Digital:
Digital photography has grown and digital film printers are able to produce high quality images. Intra-oral cameras use mostly analog technology and produce video images that can be converted into photographs with video printers. Computers are able to capture video and convert these images into digital files. Digital files are very useful. They can be brought up on a computer monitor, printed, placed into electronic charting programs, sent over e-mail, or posted on the Internet. Digital files have been used to get immediate consultations with labs, dentists, or educators via e-mail.
Newer digital cameras are available to bypass video analog to digital conversions. This avoids the resolution limitations of video and allows for higher quality images. Digital radiography in conjunction with video imaging makes electronic patient charts possible. These can be transmitted electronically anywhere in the world for consultations, verification of treatment, or to copy dental records from one dental office to another. Presently there are many high-quality intraoral analog cameras and digital cameras available.
There are many legal and technical issues with digital record keeping for the dental office. At this time week highly recommend all images be taken in 35 mm slide format and developed with a "Photo CD". The original slides would be stored in the patients chart and the digital images would be used for image use and manipulation. Hard copy (slide or print negatives) allows higher resolutions on scans and retains images in the event of electronic data loss.
Dentists can take existing film or prints and use a slide or print scanner to digitalize images into files.
There are many digital cameras available. Most have more resolution than necessary for a dentist. A few camera systems have slide copying attachments and some offer through the lens viewing. Both of these are useful to the dentist.
Useful Equipment: Nikon 880, 950, 990, 995 series with Nikon ES-E28 Slide Copy Adaptor (to make digital images from slides). A few powerful magnification lens are available to offer microscopic views (for example to enlarged a marginal area of tooth). One is Raynox MSN-500 Super macroscan Close-Up which is 2.5X magnification. However, these are rarely needed for routine intraorals.
Cameras that allow through the lens viewing (e.g. as the Olympus D500 series) are easy to use for full face images but need macro lens to get close up images.
The bests cameras are those that use traditional macro lenses with an intraoral flash. The
Fuji S1 Pro
are the first under $3000 that can use tradional macro lenses as the medical Nikor and a 105 mm macro. The
and others are also good but the cost is too high for most practitioners (over $5000).
Photography - 35 mm.:
Dental-Eye III (Yashica): Is one of the easiest and highest quality intraoral 35mm cameras available. Many other good intraoral cameras are available. Good 35 mm slide films are Kodak E100S for good even intraoral color, Fuji Veliva 50 for high color saturation. Fujichrome 100 or Extar 100 for acceptable results.
Sand Blasters / Microetchers:
MicroTin Plating System
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