Influence of pulp chamber volume on fluid dynamics during Er:YAG laser-activated irrigation:an in vitro study
JIHU Ke-di
HE Xin-yu
YU Yue
MA Li-sha
XIANG Fang-fang
HU Xin
WANG Jing-ya
PAN Chong
ZHAO Ji-zhi
Abstract：Objective To investigate the influence of pulp chamber volume on the fluid dynamics[vapor bub-ble volume,morphology and transient apical peak pressure(TAPP)]associated with Er:YAG laser-activated irriga-tion(LAI)across different pulp chamber root canal mod-els,in order to provide guidance for clinical practice.Methods This study was conducted from January to July 2024 at the Department of Stomatology,Peking Union Medical College Hospital.Four types of root canal models(3 models of each type)with different pulp chamber volumes were fabricated(V1,V2,V3,V4),with roof diameters of 4,6,8,and 10 mm,and base diameters of 2,4,6,and 8 mm,respectively.The Er:YAG laser was operated in Super Short Pulse mode at a frequency of 20 Hz.High-speed imaging was used to record vapor bubble morphology at various single-pulse energy levels(10,20,30,40,and 50 mJ),and the maximum bubble volume(Vmax)and maximum aspect ratio(R)were cal-culated.A high-frequency pulsatile pressure sensor was employed to collect voltage data at the apex to calculate TAPP at various single-pulse energy levels.Results The bubbles of all models exhibited a typical expansion-collapse cycle,with elliptical bubble morphology at Vmax.Liquid surface rupture occurred in V1 and V2 under 20-50 mJ single-pulse en-ergy conditions,while in V3 and V4,it was observed only at 50 mJ.Both pulp chamber volume and single-pulse energy significantly influenced Vmax,R,and TAPP(all P＜0.001).Intragroup comparisons showed that in V2,V3,and V4,both Vmax and TAPP were significantly greater at 40 mJ and 50 mJ compared to 10 mJ and 20 mJ(all P＜0.05),while no sig-nificant differences in TAPP were observed across energy levels in V1(P＞0.05).No significant differences in R were found across different energy levels within each group(all P＞0.05).Intergroup comparisons revealed no significant dif-ferences in Vmax among the four groups at the same single-pulse energy level(P＞0.05).However,at 40 mJ and 50 mJ,R values in V1 were significantly higher than those in the other 3 groups,and at 40 mJ,V4 exhibited the smallest R value(all P＜0.05).Except at 20 mJ,TAPP increased sequentially from V1 to V4 under the same energy condition(all P＜0.05).Linear regression analysis demonstrated that TAPP exhibited a linear growth pattern with increasing energy be-tween 30 mJ and 50 mJ in all groups,with regression coefficients(β1)of 27.967,208.564,351.980,and 1 061.570,re-spectively(95％CI:25.013-30.920,157.532-259.596,289.555-414.404,and 773.532-1 349.607,respectively;all P＜0.05).Conclusion Pulp chamber volume significantly influences fluid dynamics,including vapor bubble volume,mor-phology and TAPP,during Er:YAG LAI.For smaller pulp chambers(V1 and V2),it is recommended to use single-pulse energies below 20 mJ to reduce the risk of liquid surface rupture and potential soft tissue injury.For larger chambers(V3 and V4),single-pulse energies ranging from 30 mJ to＜50 mJ may be selected based on clinical needs.The larger the pulp chamber volume,the more significant the influence of single-pulse energy on fluid dynamics.
Keywords：laser medicineroot canal therapyEr:YAG laserfluid dynamicspulp chamber volume
Publication Date：2025-07-30
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：7( 433-439 )