Effect Of Pulp Chamber Volume On Er:Yag Irrigation Dynamics

To investigate the limitations of Er: YAG laser-activated irrigation (LAI) on apical fluid dynamics with varying pulp chamber volumes. Four tooth models with different pulp chamber volumes (V1 < V2 < V3 < V4) were filled with deionized water. An Er:YAG laser tip was positioned at the center of the pulp chamber with single-pulse energy ranging from 10 to 50 mJ.The transient apical peak pressure was measured by high frequency sensor, and the bubble dynamic process was recorded by a high-speed camera during laser-activated irrigation. Bubble dynamics analysis revealed that under identical energy levels, the elliptical morphology of maximal bubble diminished progressively as pulp chamber volume increased (V1 to V4). Analysis of results from high-frequency pulsatile pressure sensors revealed that different functional dependencies between the transient apical pressure and energy were observed across pulp chamber volumes: in V1, pressure increased linearly (first-order function), while V2–V4 exhibited a segmented dependency: quadratic function in low-energy regions (10–30 mJ) and linear growth in high-energy regions (30–50 mJ). The linear coefficients increased with larger chamber volumes (kv1< kv2 < kv3< kv4). Pulp chamber volume imposes a restrictive effect on the vapor bubble dynamics and fluid dynamics during Er: YAG laser-activated irrigation. A smaller pulp chamber volume correlates with stronger restrictive effects, resulting in diminished irrigation effectiveness in the apical region under identical irradiation parameters.