Dental radiography

Arc-melted titanium has excellent fluidity and lends itself readily to the creation of thin margins. Spmes must be carefully placed and abundant venting provided, however, to avoid holes and porosity ia the casting. The detection of defects by radiography is faciUtated by the low density of titanium, and conventional dental x-ray units may be used ia many cases. 

Soft, silvery metal whose isolation is difficult. Ytterbium fluoride is added to dental fillings (as X-ray contrast agent). Ytterbium is a constituent of rust-free special steels. Yb2Co13Fe3Mn holds the magnetic world record, but is too expensive for commercial purposes. The element is occasionally applied in nuclear medicine and radiography. It also activates phosphors that convert infrared rays into visible light. 

The entrance skin exposures are the critical parameters in terms of safety to the patient. Generally, the higher kVp exposures reach the film, while depositing less energy in the exposures to the patients. As pointed out in the introduction to the JCAHO report, the largest contributor to total population exposure to radiation from manmade sources is from diagnostic (dental and medical radiography). Clearly, X-rays need to be taken only when needed and under circumstances to reduce exposures to the patient, the medical staff, and others involved. 

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