Comparative Evaluation of Different Irrigation Techniques with Conventional Irrigation Technique for the Removal of Double Antibiotic Paste from Root Canal-An in vitro study

Complete removal of infection, rendering root canal free of an organism is the prime aim of endodontic treatment. It cannot be achieved alone by biomechanical preparation due to the complexity of root canal treatment. Therefore the use of intracanal medicament is a must. The antibiotic paste is frequently used intracanal medicament, usually in regenerative cases. Hence the aim of the is to compare different irrigation technique for removal of double antibiotic paste from root canal through a stereomicroscope. 36 single-rooted were standardized to root length of 12mm then instrumented by Protaper rotary ile up to size F4. Irrigation was done using sodium hypochlorite in between instrument change. The root canal was dried using paper point and illed by DAP and then randomly allocated to 3 groups(n=12) according to irrigation system used: conventional syringe irrigation (CSI), Passive ultrasonic irrigation(PUI), EndoVac (EV). Roots were then longitudinally sectioned using the diamond disk and studied under a stereomicroscope using a scoring scale. Data were evaluated using one way ANOVA and Tukey test. Among all experimental group CSI was least ef icient. PUI and EV showed greater ef iciency but no signi icant difference between PUI and EV, but a signi icant difference between CSI and PUI, EV (p< 0.05). Use of irrigation activation system results in ef icient removal of DAP compared to CSI.


INTRODUCTION
Endodontic regeneration has proved to be a boon in the treatment of immature permanent teeth. (Dio-genes et al., 2013;Kriplani et al., 2013) The prime protocol of this procedure is the complete canal disinfection, which is achieved by intracanal medicament. (Kamble et al., 2017;Khatod et al., 2020) TAP formulated by Hoshino et al. (1996) is most commonly used medicament for a regenerative procedure. (Hoshino et al., 1996) Use of TAP has been discontinued because of its property of discolouring the tooth structure. (Trope, 2010) Thus use DAP can be done. After complete canal disinfection removal of medicament followed by placement of MTA plugin root canal (Thibodeau and Trope, 2007;Taw ik et al., 2013). Ruparel et al. (2012); Kim et al. (2010) founded that antibiotic paste has a detrimental effect on stem cell in the apical papilla. Therefore, complete removal of medica-ment is must to avoid detrimental effect on stem cells. And to inhibit its result on sealer penetration and discolouration. (Zhu et al., 2013;Villas-Bôas et al., 2011) Conventional syringe irrigation is the most commonly practised method for removal of medicament but is not ef icient enough for complete removal of it. (Mukherjee et al., 2017;Reddy et al., 2019) Therefore use of different irrigation activation system for ef icient supply of irrigating solution and removal from the canal. (Khubchandani et al., 2017;Patni et al., 2016) EndoVac (EV) is based on apical negative pressure. (Chandak et al., 2018;Schoeffel, 2008) Developed for delivering irrigants at the apical third of canal, for cleaning of the root canal. (Ahmad et al., 1987) Passive ultrasonic irrigation (PUI) uses U ile for irrigant actuation in the root. And allow removal of bio ilm, permitting ef icacious penetration of irritants in canal walls. (Schoeffel, 2008;Sluis et al., 2007) Therefore the aim of to "evaluate the ef icacy of different irrigation activation system for removal of Double Antibiotic Paste from root canal".

MATERIALS AND METHODS
36 single-rooted teeth were collected at decoronated to simulate 12mm root length of each tooth ( Figure 1). Then instrumented up to F4 using pro taper rotary iles ( Figure 2). 1ml of 3% sodium hypochlorite was used in between every change of ile. The double antibiotic paste was prepared by mixing metronidazole and cipro loxacin in 1:1 ratio in distilled water to make a slurry-like paste (Figure 3). Using leptospiral medicament was placed in canal up to ori ice and sealed using cavit for seven days and stored at 100% humidity for 7 days. Randomly teeth were allocated in each group such that 12 in each group

Group 1(CSI)
24 gauge needle was used and placed as apically as possible such that it does not adhere to the canal wall. 10 ml/min of 3% NaOCl was used as an irrigating solution ( Figure 4).

Group 2 (PUI)
#15 U ile was placed 1mm short of working length without adhering canal wall. The ile was activated with a power setting of 6 and 10ml/min 3% NaOCl was agitated using it ( Figure 5).
After this inal wash using 1 ml of NS to remove remaining NaOCl, the canal was dried using paper point, and longitudinal cuts were placed on root using diamond disk deep enough but not penetrating the canal. Using chisel root was split into two halves ( Figure 8). And then evaluated under stereomicroscope 25X (Zeiss) using scoring scale by Sluis et al. (2007). (Shin et al., 2010) score 0 -the canal was empty; score 1-DAP was present in less than half of the canal; score 2 -DAP covered more than half of the canal, and score 3 -the canal was illed with DAP ( Figure 9, Figure 10, Figure 11).
"Statistical analysis was done by descriptive, inferential statistics using one way ANOVA and multiple comparisons Tukey test and software used in the analysis were SPSS 24.0 version and EPI-INFO 7.0 version, p<0.05 is considered as the level of significance".

RESULTS AND DISCUSSION
Mean intracanal medicament left in conventional syringe irrigation was 2.41±0.51, in passive ultrasonic irrigation it was 1.25±0.45, and in EndoVac it was 1.41±0.51 (Table 1). By using one way ANOVA statistically signi icant variation was found in mean intracanal medicament removal in three groups (F=16.60,p=0.0001). By using multiple comparisons, Tukey Test statistically signi icant difference was found in mean intracanal medicament removal between conventional syringe irrigation and passive ultrasonic irrigation (p=0.001) and between traditional irrigation of syringe and Endovac (p=0.0001) and no signi icant difference was found between passive ultrasonic irrigation and Endovac (p=0.690) ( Table 2).

Figure 1: Single rooted specimen collected
It resulted that PUI was ef icient enough for removal of DAP. A similar effect was seen by EV. conventional syringe irrigation is most frequently used for removal. However oval extensions of the canal in the apical area of the canal and inadequate delivery of irrigant might render it as failure and medicament may be left in canal. For adequate removal of medicament, there must be adequate delivery   of irrigant up to WL. (Nielsen and Baumgartner, 2007;Taşdemir et al., 2011) During PUI, acoustic microstreaming and cavitation resulting in ef icient removal of debris or medication from canal compared to CSI and EV. But no signi icant difference compared to EV. Transmission of energy from ultrasonically oscillating ile to irrigant in the canal is a principle of PUI. (Shin et al., 2010;Kenee et al., 2006) PUI was found to be ef icient enough for removal of medicament in many studies, and suggestive of improved cleanliness of canal walls. (Ricucci and Langeland, 1997;Jiang et al., 2011) PUI leads to increased velocity of irrigant low which might result in its ef iciency. Results of the current study for PUI group are the same as that of other studies in which maximum of Ca(OH)2 was removed but not totally. It can be because of lowest power intensity of the ultrasonic device. Jiang et al. (2011); Desai and Himel (2009) have seen cleaning ef iciency increases following the output of the ultrasonic device. In future studies, a positive result might be gained using the increased output of ultrasonic activation. EV offer safe delivery of irrigant up to the apex of root and effective cleansing, especially in the apical region of the root canal. (Ahmetoglu et al., 2013;Gu et al., 2009) The EndoVac System showed ef icient cleaning of the canal compared to CSI but no signi icant difference between PUI. Other studies were also following the above result.EV comprises of macro and microcannula. Cannula connected to a high-speed suction produces negative pressure which drags irrigant up to the apex of the cannula and evacuates the irrigant with debris through small holes. However, in our study, total success for removal of DAP was not attained. It might be because microcannulas and microcannulas might get obstructed by particles of DAP paste, which could have caused less irrigation solution to reach the apical region. (Gu et al., 2009)

CONCLUSION
Within con inement of study, it can be stated that the use of irrigation activation system results in meliorate removal of medicament compared to CSI. Use of Passive ultrasonic irrigation showed promising results in removal of intracanal remedy compared to routinely followed syringe irrigation. Thus, the use of irrigation activation system might result in improved seal post obturation.