中文摘要：

目的：比较4种不同技术对弯曲根管根尖区气锁的去除效果。方法：40个45°弯曲模拟树脂根管经Wave One Primary预备后,软蜡封闭根尖孔,所有样本随机分为4组（n=10）。通过30 G侧方开口冲洗针头将显影液注射入根管内,锥形束CT（cone-beam computer tomography,CBCT）扫描,计算根管内气锁体积,随后分别使用光诱导光声流（photon-induced photoacoustic streaming,PIPS）激光荡洗法、牙胶尖法、超声荡洗法和声波荡洗法去除根管内气锁。CBCT扫描计算剩余气锁体积。结合根管内气锁体积和剩余气锁体积,计算气锁去除百分比,进一步计算初始和剩余气锁长度。结果：各组初始气锁体积差异无统计学意义（P〉0.05）。PIPS激光荡洗组的剩余气锁体积为0 mm3,牙胶尖组为（0.02±0.07）mm3,两组均显著小于超声组[（0.20±0.09）mm3）]和声波组[（0.23±0.06）mm3,P〈0.001]。计算气锁去除百分比显示,PIPS激光荡洗组和牙胶尖组分别为100.00%（100.00%,100.00%）和100.00%（77.66%,100.00%）,亦显著高于超声荡洗组[70.37%（56.41%,91.43%）]和声波荡洗组[63.54%（51.47%,74.00%）,P〈0.001]。剩余气锁长度方面,PIPS激光荡洗组是0 mm,牙胶尖组是（0.15±0.47）mm,两组间差异无统计学意义（P〉0.05）,但均显著小于超声组[（2.21±0.09）mm]和声波组[（2.34±0.08）mm,P〈0.001],超声组和声波组的剩余气锁长度约为荡洗锉尖到根尖孔的距离。结论：PIPS激光荡洗法和牙胶尖法能够有效去除弯曲根管根尖区气锁。

英文摘要：

Objective： To compare the effect of four different techniques on removal of vapor lock in the apical region of curved root canals. Methods： Forty simulated resin root canals with 45° curvature were prepared using Wave One Primary,then the apical foramen were sealed with soft wax. The teeth were divided randomly into 4 groups thereafter（ n = 10）. Contract solution was injected into the canals using a 30 G side-vented needle and scanned with cone-beam CT（ CBCT） to identify the volume of the vapor lock. Four different techniques including photon-induced photoacoustic streaming（ PIPS） laser-activated irrigation,gutta-percha cone technique,ultrasonic irrigation,and sonic irrigation were used to remove the vapor locks in the root canals. The residual volume of the vapor lock was identified again using CBCT scanning data. Accordingly,the reduction rates of the vapor lock were calculated. Furthermore,the initial and residual vapor lock length was calculated. The data were analyzed by using the One-Way ANOVA analysis and Kruskal-Wallis H test at a significance level of P 〈0. 05. Results： There was no significant difference in the initial vapor lock volume（ P〉 0. 05）. Residual volume of the vapor lock for PIPS laser-activated irrigation was 0 mm3,and that for gutta-percha cone technique was（ 0. 02 ± 0. 07）mm3,significantly lower than those of ultrasonic and sonic irrigation,the values being（ 0. 20 ± 0. 09）mm3and（ 0. 23 ± 0. 06） mm3（ P 〈0. 001）,respectively. The reduction rates of the vapor lock of PIPS laser-activated irrigation and gutta-percha cone technique were 100. 00%（ 100. 00%,100. 00%） and100. 00%（ 77. 66%,100. 00%）,respectively,significantly higher than those of ultrasonic irrigation[70. 37%（ 56. 41%,91. 43%） ]and sonic irrigation [63. 54%（ 51. 47%,74. 00%）,P 〈0. 001].The length of the residual vapor lock for PIPS laser-activated irrigation was 0 mm,and that for gutta-percha cone technique was（ 0. 15 ± 0. 47） mm,significantly lower than those o