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P P Fan

Publications and source records attributed to P P Fan.

7 recordsLinked to original sources
PubMed1998

Choosing the right clinical camera. Part I.

Our recommendation is a 90-105 mm macro lens focusing from 1:1 to infinity and a minimum aperture of f/32. A reputable brand should be preferred: Nikon, Canon, Minolta, Sigma etc.... A 105 mm macro lens allows for adequate working distance (approx. 130 mm for a straight view at 1:1 magnification). A 105 mm macro lens induces insignificant perspective distortion and has a large range of aperture. Lastly, it provides for a magnification scale ranging from 1:1 to infinity and is optically excellent. The working distance of current camera systems extends approximately from 4 4/8" or 114 mm, to 7" or 180 mm, at 1:1 magnification. Again these differences are mainly due to lens design and mounted components, (filters, bracket, lighting systems). A minimum of 5" or 125 mm of working distance is desirable for physical access of your camera and proper illumination of the photographed object. However, adequate lighting also depends upon the type and location of your lighting system especially for higher magnification photographs. Part II will examine the different lighting systems on the market and try to decide which is most adapted to your needs. It will answer your questions about the use of the operatory light while focusing, the red eye problem and the use of polarizing filters to decrease the amount of reflection from the flash.

Dental Equipment↗
PubMed1998

Choosing the right clinical camera. Part II.

From a practical standpoint, both ring and dual flash are easier to control for the operator. It is not necessary to remember to put the flash on the side of the mirror or to rotate the flash to avoid unwanted shadows. The point source flash requires a learning curve and the dual point source flash, away from the lens, has limited applications. The lighting quality brings out the third dimension in photography and is therefore among the most important factors when taking image quality into consideration. The dual source flash on the lens system provides a more pleasing and natural illumination than the other systems. The Nikon SB21-B fulfills these requirements while offering the possibility to be used as a single source flash unit. Furthermore, the flash unit's close proximity to the lens allows the light to reach virtually any area in the mouth. Lastly, the TTL option takes care of the concern regarding the consistency of the light intensity and significantly speeds up the recycling time.

Dental Equipment↗
PubMed1997

Complete denture impressioning technique.

This article describes a technique that simplifies the making of an edentulous arch impression before the fabrication of a complete denture. Making an impression of an edentulous arch requires a unique combination of managing movable soft tissue commensurate with integrating different materials and a technique for accurate reproduction. The technique described requires a two-phase approach using a syringeable addition silicone during the border molding process and a condensation silicone wash material to capture the soft tissue while the functional border molding is repeated. These more recently developed products allow us to achieve similar results and are easier, faster, and more predictable than those products used previously.

Dental Impression Materials↗