Effectiveness of single-use tips for dental air-water syringes

Objectives: To evaluate the effectiveness of different single-use syringe (SUS) dental tips, firstly by measuring the pressure output. Secondly, to investigate their drying effectiveness, recording the peak force at failure during tensile testing of dentine specimens bonded to glass fibre reinforced composite posts. Methods: The air-water syringe was set and calibrated to 50 PSI. The pressure of the air expressed from the syringe with no tip attached was measured. SUS tips were then attached (with adapter if applicable). The output air pressure was measured. Six SUS tips were tested, Seal Tight, Pro-Tip Plus, FASTips, Sani-Tips, Crystal Tips and Safe Tips EZ. Ethical approval for the use of human teeth was granted. Twenty unrestored, caries free, third molar teeth were sectioned to produce 60 specimens, stored in phosphate buffered saline and randomly allocated into six groups of ten specimens. They were mounted in acrylic and polished. Specimens were dried with a specific SUS tip under standardised conditions, treated using a 3-step etch, prime, bond technique and then had a post bonded perpendicular to the exposed dentine surface. Posts were attached to a microtensile testing machine and the force to detach them measured. Results: one of the tip delivered output pressure lower than the input pressure: Pro-Tip 42 PSI (SD 5.07). The average tensile force at failure was significantly different between groups (P = 0.019) ANOVA analysis.   Conclusions: The pressure output of the syringe is influenced by the SUS tip. The drying effectiveness of the SUS tips was different.