Apical pressure created during irrigation with the GentleWave™ system compared to conventional syringe irrigation.
OBJECTIVE
The purpose of this study is to compare pressures at the apical foramen created by conventional syringe irrigation and the GentleWave™ System, which releases high-velocity degassed irrigants to the pulp chamber and uses broad-spectrum sound energy for cleaning.


METHODS
The apical pressure generated during irrigation was measured for palatal and distobuccal root canals of four extracted maxillary molars after no instrumentation, minimal instrumentation to a size #15/.04, instrumentation to a size #40/.04 taper, and after perforating the apical foramen to size #40. The root canals opened into an air-tight custom fixture coupled to a piezoresistive pressure transducer. Apical pressures were measured for the GentleWave™ System and syringe-needle irrigation at different irrigant flow rates, with the needle tip at 1 and 3 mm from the apical foramen using 30-gauge (G) open-ended or side-vented safety tip needles.


RESULTS
The GentleWave™ System generated negative apical pressures (P < 0.001 compared with syringe irrigation); the mean pressures were between -13.07 and -17.19 mmHg. The 30 G needles could not reach the 1 and 3 mm from the working length in uninstrumented and 1 mm in minimally instrumented canals. The mean positive pressures between 6.46 and 110.34 mmHg were measured with needle irrigation depending on the flow rate, needle insertion depth, and size of the root canal.


CONCLUSIONS
The GentleWave™ System creates negative pressure at the apical foramen during root canal cleaning irrespective of the size of canal instrumentation. Positive apical pressures were measured for syringe irrigation.


CONCLUSIONS
Negative pressure during irrigation contributes to improved safety as compared to high-positive pressure.
Division of Endodontics, Department of Oral Biological and Medical Sciences, Faculty of Dentistry, The University of British Columbia, 2199 Wesbrook Mall, Vancouver, BC, V6T 1Z3, Canada. markush@dentistry.ubc.ca.
Markus
M
Haapasalo
Division of Endodontics, Department of Oral Biological and Medical Sciences, Faculty of Dentistry, The University of British Columbia, 2199 Wesbrook Mall, Vancouver, BC, V6T 1Z3, Canada.
Ya
Y
Shen
Division of Endodontics, Department of Oral Biological and Medical Sciences, Faculty of Dentistry, The University of British Columbia, 2199 Wesbrook Mall, Vancouver, BC, V6T 1Z3, Canada.
Zhejun
Z
Wang
Division of Endodontics, Department of Oral Biological and Medical Sciences, Faculty of Dentistry, The University of British Columbia, 2199 Wesbrook Mall, Vancouver, BC, V6T 1Z3, Canada.
Ellen
E
Park
Sonendo, Inc., Laguna Hills, CA, USA.
Allison
A
Curtis
Sonendo, Inc., Laguna Hills, CA, USA.
Payal
P
Patel
Sonendo, Inc., Laguna Hills, CA, USA.
Prashanthi
P
Vandrangi
D003786:Dental Pulp Cavity / Q000187:drug effects*; D004867:Equipment Design; D006801:Humans; D066298:In Vitro Techniques; D008963:Molar; D011312:Pressure; D012388:Root Canal Irrigants / Q000008:administration & dosage*; D013594:Syringes; D007507:Therapeutic Irrigation / Q000295:instrumentation*; D019227:Tooth Apex
D012388:Root Canal Irrigants
Apical pressure; GentleWave; Irrigation; Needle; Root canal; Syringe