RESUMEN
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 WaveOne 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)mm3 and (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％) and 100.00％ (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 of ultrasonic and sonic irrigation,values being (2.21 ±0.09) mm and (2.34 ±0.08) mm (P ＜0.001),respectively.The length of the residual vapor locks in the ultrasonic and sonic group remained approximately the same as the distance between the working tip and the apical foramen.Conclusion:PIPS laser activated irrigation and gutta-percha cone technique could remove the vapor lock from the apical region of curved canals effectivelv.
RESUMEN
Objective: To evaluate effect of the morphology of simulated S-shaped root canals with Reciproc or Mtwo instruments on root canal irrigation. Methods: A total of 40 simulated S-shaped resin blocks were randomly divided into 2 groups (n=20), which was prepared by Reciproc or Mtwo. Blue ink was injected with constant speed and volume into the canals using 30G lateral opening syringe. hTe distance from needle tip to apex and vapor lock length were measured. A type of 25# 0.04 gutta-percha point was used to stir and remove the vapor lock. hTe time for removal of the vapor lock was recorded. Another syringe was used to inject saline into the canals and to measure the length of stagnant water. Results: hTe distance from needle tip to apex in the Reciproc group was signiifcantly longer than that in the Mtwo group [(4.276 ± 0.221) mm vs (3.459 ± 0.205) mm,P<0.05]. The vapor lock length in the Reciproc group was signiifcantly longer than that in the Mtwo group [(4.472 ± 0.230) mm vs (3.668±0.217) mm,P<0.05]. hTe time to remove vapor lock was signiifcantly shorter in the Reciproc group than that in the Mtwo group [(10.13 ± 1.79) s vs (15.29 ± 2.15) s,P<0.05]. The length of stagnant water was also shorter in the Reciproc group than that in the Mtwo group[(1.351 ± 0.142) mm vs (2.245 ± 0.206) mm,P<0.05]. Conclusion: hTe morphology of S-shaped root canal affects the root canal irrigation. hTe effect of root canal irrigated by Reciproc is better than that by Mtwo.