The radiological examinations in dentistry may be classified into " intraoral " where the film or sensor is placed in the mouth, the purpose being to focus on a small region of the oral-maxillofacial region and " extraoral " where the film or sensor is placed outside the mouth aiming to visualize the entire oral maxillofacial region.
32.
Suni and his teams also engaged in U . S . Government sponsored research, claiming to have received several million dollars in research grants from the National Cancer Institute ( digital mammography ), National Institute for Dental Research ( intraoral radiography ) and the Defense Advanced Research Projects Agency ( DARPA ) ( optical processing ) . [ 21 ]-[ 22]
33.
A study conducted by measuring the intraoral vapour levels over a 24-hour period in patients with at least nine amalgam restorations showed that the average daily dose of inhaled mercury vapour was 1.7 ?g ( range from 0.4 to 4.4 ?g ), which is approximately 1 % of the threshold limit value of 300 to 500 ?g / day established by the WHO, based on a maximum allowable environmental level of 50 ?g / day in the workplace.
