Boutsioukis C, Kastrinakis E, Lambrianidis T, Verhaagen B, Versluis M, van der Sluis L W M
Physics of Fluids Group, Faculty of Science and Technology, University of Twente, Enschede, The Netherlands; MESA+ Institute for Nanotechnology, University of Twente, Enschede, The Netherlands.
Int Endod J. 2014 Feb;47(2):191-201. doi: 10.1111/iej.12133. Epub 2013 May 25.
(i) To evaluate the effect of needle type and insertion depth, root canal size and irrigant flow rate on the entrapment of air bubbles in the apical part of a root canal (apical vapor lock) during syringe irrigation using experiments and a Computational Fluid Dynamics (CFD) model, (ii) to investigate whether the irrigant contact angle affects bubble entrapment, (iii) to examine if an established vapor lock can be removed by syringe irrigation.
Bubble entrapment during irrigation of straight artificial root canals of size 35 or 50 was evaluated by real-time visualizations. The irrigant was delivered by a closed-ended or an open-ended needle positioned at 1 or 3 mm short of working length (WL) and at a flow rate of 0.033-0.260 mL s(-1) . Results were analysed by nonparametric tests at 0.05 significance. Selected cases were also simulated by a two-phase CFD model.
A vapor lock was observed in 48% of the cases investigated experimentally. Increasing the apical size, using an open-ended needle, positioning the needle closer to WL and delivering the irrigant at higher flow rate resulted in significantly smaller vapor lock. An increased contact angle resulted in the entrapment of a larger bubble when a low flow rate was used. Both brief insertion of the needle to WL whilst irrigating at a flow rate of 0.083 mL s(-1) and delivering the irrigant at 0.260 mL s(-1) without changing the needle position were capable of removing an established vapor lock.
Apical vapor lock may occur under certain conditions, but appears to be easily prevented or removed by syringe irrigation.
（i）通过实验和计算流体动力学（CFD）模型，评估针型、插入深度、根管尺寸和冲洗液流速对根管冲洗时根尖部气泡截留（根尖气锁）的影响；（ii）研究冲洗液接触角是否影响气泡截留；（iii）检查已形成的气锁能否通过冲洗去除。
通过实时可视化评估在冲洗尺寸为35或50的直形人工根管时的气泡截留情况。冲洗液由封闭端或开口端针输送，针位于距工作长度（WL）短1或3 mm处，流速为0.033 - 0.260 mL s⁻¹。结果采用非参数检验进行分析，显著性水平为0.05。选定的案例也用两相CFD模型进行模拟。
在48%的实验研究案例中观察到气锁现象。增大根尖尺寸、使用开口端针、将针放置得更靠近WL以及以更高流速输送冲洗液，会使气锁明显变小。当使用低流速时，接触角增大导致截留更大的气泡。在以0.083 mL s⁻¹流速冲洗时将针短暂插入至WL，以及在不改变针位置的情况下以0.260 mL s⁻¹输送冲洗液，均能够消除已形成的气锁。
根尖气锁可能在某些条件下发生，但似乎可通过冲洗轻易预防或消除。
