Exposure of patient and dental staff to fine and ultrafine particles from scanning spray.

OBJECTIVES: Sprays containing fine and ultrafine particles are commonly used for optical scanning. The aim of this study was to measure the particle exposure of patient and dentist during application of scanning spray and to evaluate measures for its reduction. MATERIALS AND METHODS: A lower molar in a dental simulator was powdered with scanning spray. Patient's particle exposure was measured by a condensation particle counter in the nasal region of the simulator without (P) and with rubber dam (PC). Dentist's exposure (D) was measured behind a surgical mask. Particle concentrations were determined 5-fold without suction (NS), using conventional dental suction (CDS), or high volume evacuation (HVE). RESULTS: Mean background air particle concentrations for the patient were 3.3 x 10(3) and 1.3 x 10(3) pt/cm(3) for the dentist. Particle concentrations increased after spraying; mean cumulated additional particle exposures for the patient were the following: P-NS 7.2 x 10(6), P-CDS 4.6 x 10(6), P-HVE 2.4 x 10(4); using rubber dam: PC-NS 3.6 x 10(6), PC-CDS 3.3 x 10(5), PC-HVE 2.2 x 10(5). The particle exposures of the dentist were the following: D-NS 9.7 x 10(5), D-CDS 1.8 x 10(5), D-HVE 1.6 x 10(4). CONCLUSIONS: The use of HVE is recommended to reduce exposure of patients and dental staff to fine and ultrafine particles when using scanning sprays. CLINICAL RELEVANCE: Effective protection is available for staff and patient by means of high volume evacuation. In patients suffering from obstructive lung diseases, the use of scanning sprays should be avoided altogether.