In vitro effect of air pressure and powder flow rate operating parameters on the air-abrasion cutting rate in a static cutting mode

الملخص EN

Objective: To evaluate the effect of air pressure and powder flow rate (PFR) operating parameters on the air-abrasion cutting rate in a static cutting mode using alumina and bioactive glass (BAG) abrasive powders.

Methods: The operating parameters investigated were: air pressure (20, 40, 60 and 80 psi), PFR (1, 3 and 5 dial settings) and the abrasive powder itself (BAG-45S5 vs.

alumina), presenting 12 experimental groups (n=20).

The CR was determined as the time in seconds it took the abrasive stream to penetrate a standardised thickness of an enamel analogue block.

Data was statistically analysed using two-way analysis of variance (ANOVA) and Tukey post-hoc testing (p<0.05).

Results: PFR affected significantly the CR of air-abrasion for both abrasive powders.

The increase in air pressure increased CR significantly in all groups except the jump from 60 to 80 psi in BAG powder group.

The CR in Al2O3 powder groups was significantly greater than that in BAG groups.

Conclusion: Air pressure and PFR have an important role in determining the CR of air abrasion.

BAG powder is more conservative than Al2O3 powder encouraging their role in minimally invasive dentistry.

Key words: Air-abrasion, Cutting rate, Bio-active glass (BAG), Alumina, Powder flow rate (PFR), Air pressure