ABSTRACT
Aim
To evaluate the effectiveness of laser-activated irrigation (LAI) and ultrasonic irrigation (UI) in the removal of calcium hydroxide [Ca(OH)2] and modified triple antibiotic paste (MTAP) from the root canals.
Materials and methods
Root canals of freshly extracted human permanent maxillary incisors (n = 80) were prepared. The root canals of half sample (n = 40) were filled with Ca(OH)2 and the other half (n = 40) with MTAP, in which propylene glycol was used as a vehicle. After 14 days, roots were randomly assigned to four groups (n = 20) according to the irrigation technique used—group I [Ca(OH)2 with UI], group II (MTAP with UI), group III [Ca(OH)2 with LAI], group IV (MTAP with LAI). The roots were sectioned, and the intracanal medicament residues were evaluated at 25× magnification under stereomicroscope using 4-grade scoring system.
Statistical analysis
One-way analysis of variance (ANOVA) and post hoc Tukey tests were performed.
Results
Laser-activated irrigation (LAI) was found to be superior compared to UI. Ca(OH)2 was better removed compared to MTAP with either of the irrigation techniques. A statistically significant difference was found between the Ca(OH)2 with LAI and MTAP with UI groups in all the regions, that is, coronal, middle, and apical thirds.
Conclusion
Laser-activated irrigation (LAI) was superior to UI in removing Ca(OH)2 and MTAP. Ca(OH)2 was better removed than MTAP, irrespective of the technique used. However, none of the irrigation techniques could completely remove the intracanal medicament from the root canals.
How to cite this article
Swathi P, Uloopi KS, Vinay C, et al. Effectiveness of Laser-activated and Ultrasonic Irrigation Techniques in Removal of Calcium Hydroxide and Modified Triple Antibiotic Paste from the Root Canals: An In Vitro Evaluation. Int J Clin Pediatr Dent 2023;16(S-1):S1–S5.
Keywords: Calcium hydroxide, Laser-activated irrigation, Root canals, Triple antibiotic paste, Ultrasonic irrigation
Introduction
Pulpal infection leading to periapical pathosis is mainly due to the presence of pathogens in the pulp canal system. In order to eliminate these, various means, such as thorough biomechanical preparation, irrigants, and intracanal medicaments, are used. Biomechanical preparation targets cleaning, shaping, and disinfecting the pulp canal system. Nevertheless, biomechanical preparation alone can leave untouched areas of microbes, which can cause persistent inflammation.1 Hence, chemical agents that act against these bacteria have come into play.
Calcium hydroxide [Ca(OH)2] is a well-established and popularly used intracanal medicament due to its good antimicrobial efficacy and biocompatibility.2 The intracanal medicament of choice in endodontic revascularization cases is triple antibiotic paste (TAP), which is composed of ciprofloxacin, metronidazole, and minocycline. It is an effective antimicrobial agent that creates conditions suitable for tissue revascularization.3,4 Minocycline, due to its discoloration effect on teeth, is eliminated and replaced with clindamycin, thereby redefining it MTAP.5
Prior to root canal obturation, these intracanal medicaments need to be completely removed from the canals as they can affect the quality of root canal obturation. Irrigating solutions alone cannot be effective in removing medicaments from the root canal walls.6 Hence, advanced irrigant agitation techniques, such as sonics and ultrasonics, have been proposed. Recently, irrigant agitation using lasers has gained attention.
Various investigations have evaluated different irrigation techniques in removing Ca(OH)2 or TAP alone. Therefore, the current research aimed to compare the effectiveness of LAI and UI techniques in removing Ca(OH)2 and MTAP from the root canals.
Materials and Methods
The in vitro study was approved by Institutional Review Board (VDC/IEC/2018/31). The study's sample size was derived as 79 teeth using the N power formula, keeping the power of study at 80% and α error at 5%. A total of 80 human permanent maxillary central or lateral incisor teeth having single root canal morphology that were freshly extracted (within 3 months) due to periodontal reasons were included. Teeth with decay or fractures below the cementoenamel junction, internal or external resorption, teeth with open apices, and teeth that were previously endodontically treated were excluded from the study.
Specimen Preparation
Extracted teeth were disinfected using 10% formalin solution (Centers for Disease Control and Prevention guidelines).7 Tissue remnants and hard deposits on the tooth surface were removed with ultrasonic tips. The coronal part of the tooth was sectioned at 15 mm from the apex using a diamond disk to standardize the length. Access opening was done using a size 5 round diamond bur. Canals were chemomechanically prepared using Kerr hand files (Mani, Japan) and ProTaper universal rotary files (Dentsply, Maillefer, Switzerland). Irrigation of canals was carried out using 2 mL of 3% sodium hypochlorite (NaOCl). Lastly, irrigation was done with 17% ethylenediaminetetraacetic acid (EDTA) for a duration of 1 minute, followed by 5 mL of 3% NaOCl for 1 minute, and then rinsed with 5 mL of distilled water to wash out irrigants from the canals thoroughly. Later drying of the canals was done using sterile paper points. After coating the intracanal medicaments, that is, either Ca(OH)2 or MTAP, access was sealed with temporary restorative material (3M Cavit, Germany), and root apices were sealed with 2 mm of composite resin (Tetric N-Ceram, Ivoclar Vivadent, India). The specimens were stored at 37oC for 14 days and then divided into four groups randomly.
Group I (Ca(OH)2 with UI) (n = 20)—Ca(OH)2 (RC-Cal, Prime Dental, Maharashtra, India) was coated to the canal walls. UI was carried out using irrisafe tips (Satelec, Acteon, Merignac Cedex, France) with a piezoelectric unit (Acteon Satelec, P-5 booster, Germany) at a power setting of six for 1 minute and 30 KHz.
Group II (MTAP with UI) (n = 20)—prepared MTAP [ciprofloxacin (500 mg), metronidazole (400 mg), and clindamycin (150 mg) with propylene glycol as a vehicle] was coated to canal walls using lentulo-spiral. UI was carried out the same as in group I.
Group III [Ca(OH)2 with LAI] (n = 20)—LAI was carried out with the 2780 nm erbium, chromium-doped yttrium, scandium, gallium and garnet (Er,Cr:YSGG) laser (Waterlase MD; Biolase Technology, Inc, San Clement, California, United States of America) and a radial firing tip of diameter 415 µm (RFT3 Endolase, Biolase Technology, Inc, United Stated of America). The panel settings were 1.25 W, 30 Hz, 140 µs pulse duration, 30% water, and 20% air.
Group IV (MTAP with LAI) (n = 20)—prepared MTAP was coated as in group II, and LAI was performed the same as in group III.
Microscopic Analysis
After irrigation, the teeth were split longitudinally using a diamond disk, subjected to stereomicroscope under 25× magnification, and images were taken. These obtained images were subjected to Image-Pro 6.0 version software for image analysis to calculate the residual amount left in the canals and scored. The scoring criteria, as stated by van der Sluis et al.,8 was taken as reference and modified, where score 1 denotes residues ranging below 25%, and score 2 is residues ranging from 25 to 50%. Score 3 indicates residues ranging from 50 to 75%, and score 4 is residues >75% (Fig. 1).
Fig. 1.
Scoring criteria followed in the study. Score 1 denotes residues <25%, score 2 is 25–50%, score 3 is 51–75%, and score 4 is residues >75%
Statistical Analysis
The data obtained were statistically analyzed using parametric tests as the data followed a normal distribution. A one-way ANOVA test was carried out to compare the mean residual amount of intracanal medicament. Post hoc analysis was done for pairwise comparisons using Tukey's test. A probability value of p ≤ 0.05 was considered for statistical significance, and p ≤ 0.001 was highly significant for all the comparisons performed using Statistical Software for the Social Sciences (Version 21.0, Armonk, New York: IBM Corp).
Results
On intragroup comparison, the effectiveness of irrigation protocol was found to be greatest in the coronal third and least in the apical third irrespective of medicament and irrigation technique used. A statistically significant difference was observed between the coronal, middle, and apical thirds in all the groups (Table 1). On pairwise comparison, coronal and apical thirds in all the groups showed statistically significant differences (Table 2).
Table 1.
Intragroup comparison of LAI and UI in the removal of Ca(OH)2 and MTAP from the coronal, middle, and apical thirds of the root canals
| Group | Region | Mean residual amount | Standard deviation | p-value |
|---|---|---|---|---|
| Group I (n = 20) Ca(OH)2 with UI |
Coronal | 0.4500 | 0.60481 | 0.052*S |
| Middle | 0.8500 | 0.87509 | ||
| Apical | 1.1000 | 0.96791 | ||
| Group II (n = 20) MTAP with UI |
Coronal | 1.0000 | 0.91766 | 0.005*S |
| Middle | 1.5500 | 0.88704 | ||
| Apical | 2.0000 | 0.97333 | ||
| Group III (n = 20) Ca(OH)2 with LAI |
Coronal | 0.2000 | 0.41039 | 0.030*S |
| Middle | 0.5000 | 0.60698 | ||
| Apical | 0.8000 | 0.95145 | ||
| Group IV (n = 20) MTAP with LAI |
Coronal | 0.7000 | 0.80131 | 0.006*S |
| Middle | 1.1000 | 1.02084 | ||
| Apical | 1.7500 | 1.16416 |
*S, significant; one-way ANOVA test
Table 2.
Pairwise comparison of laser-activated and UI in the removal of intracanal medicaments from the coronal, middle, and apical thirds of the root canals
| Pairwise comparison | Mean difference | p-value | ||
|---|---|---|---|---|
| Group I (n = 20) Ca(OH)2 with UI |
Coronal | Middle | 0.40000 | 0.288 |
| Apical | 0.65000* | 0.042*S | ||
| Middle | Apical | 0.25000 | 0.610 | |
| Group II (n = 20) MTAP with UI |
Coronal | Middle | 0.55000 | 0.155 |
| Apical | 1.00000* | 0.003*S | ||
| Middle | Apical | 0.45000 | 0.282 | |
| Group III (n = 20) Ca(OH)2 with LAI |
Coronal | Middle | 0.30000 | 0.364 |
| Apical | 0.60000* | 0.022*S | ||
| Middle | Apical | 0.30000 | 0.364 | |
| Group IV (n = 20) MTAP with LAI |
Coronal | Middle | 0.40000 | 0.425 |
| Apical | 1.05000* | 0.005*S | ||
| Middle | Apical | 0.65000 | 0.111 | |
*S, significant; post hoc Tukey test
On intergroup comparison, LAI was noticed to be superior compared to UI in the removal of both intracanal medicaments. Ca(OH)2 was better removed compared to MTAP with both irrigation techniques. A statistically significant difference was seen between the groups in coronal, middle, and apical thirds (Table 3). On pairwise comparison, there was a statistically significant difference between the Ca(OH)2 with LAI and MTAP with UI groups in all the regions, that is, coronal, middle, and apical thirds (Table 4).
Table 3.
Intergroup comparison of laser-activated and UI in the removal of Ca(OH)2 and MTAP from coronal, middle, and apical thirds of the root canals
| Mean | SD | p-value | ||
|---|---|---|---|---|
| Coronal | Group I (n = 20) Ca(OH)2 with UI | 0.4500 | 0.60481 | 0.005*S |
| Group II (n = 20) MTAP with UI | 1.0000 | 0.91766 | ||
| Group III (n = 20) Ca(OH)2 with LAI | 0.2000 | 0.41039 | ||
| Group IV (n = 20) MTAP with LAI | 0.7000 | 0.80131 | ||
| Middle | Group I (n = 20) Ca(OH)2 with UI | 0.8500 | 0.87509 | 0.002*S |
| Group II (n = 20) MTAP with UI | 1.5500 | 0.88704 | ||
| Group III (n = 20) Ca(OH)2 with LAI | 0.5000 | 0.60698 | ||
| Group IV (n = 20) MTAP with LAI | 1.1000 | 1.02084 | ||
| Apical | Group I (n = 20) Ca(OH)2 with UI | 1.1000 | 0.96791 | 0.001**HS |
| Group II (n = 20) MTAP with UI | 2.0000 | 0.97333 | ||
| Group III (n = 20) Ca(OH)2 with LAI | 0.8000 | 0.95145 | ||
| Group IV (n = 20) MTAP with LAI | 1.7500 | 1.16416 | ||
| Total | Group I (n = 20) Ca(OH)2 with UI | 0.6000 | 0.68056 | 0.005*S |
| Group II (n = 20) MTAP with UI | 1.1500 | 1.18210 | ||
| Group III (n = 20) Ca(OH)2 with LAI | 0.3000 | 0.47016 | ||
| Group IV (n = 20) MTAP with LAI | 0.9500 | 0.60481 |
*S, significant; **HS, highly significant; one-way ANOVA test
Table 4.
Pairwise comparison of laser-activated and UI in the removal of intracanal medicaments from the root canals
| Region | Pairwise comparison | Mean difference | p-value | |
|---|---|---|---|---|
| Coronal | Group I—Ca(OH)2 with UI | Group II—MTAP with UI | −0.550 | 0.077 |
| Group III—Ca(OH)2 with LAI | 0.250 | 0.683 | ||
| Group IV—MTAP with LAI | −0.250 | 0.683 | ||
| Group II—MTAP with UI | Group III—Ca(OH)2 with LAI | 0.800 | 0.004*S | |
| Group IV—MTAP with LAI | 0.300 | 0.543 | ||
| Group III—Ca(OH)2 with LAI | Group IV—MTAP with LAI | −0.500 | 0.126 | |
| Middle | Group I—Ca(OH)2 with UI | Group II—MTAP with UI | −0.700 | 0.057 |
| Group III—Ca(OH)2 with LAI | 0.350 | 0.575 | ||
| Group IV—MTAP with LAI | −0.250 | 0.795 | ||
| Group II—MTAP with UI | Group III—Ca (OH)2 with LAI | 1.050 | 0.001**HS | |
| Group IV—MTAP with LAI | 0.450 | 0.355 | ||
| Group III—Ca(OH)2 with LAI | Group IV—MTAP with LAI | −0.600 | 0.131 | |
| Apical | Group I—Ca(OH)2 with UI | Group II—MTAP with UI | −0.900 | 0.033*S |
| Group III—Ca(OH)2 with LAI | 0.300 | 0.788 | ||
| Group IV—MTAP with LAI | −0.650 | 0.190 | ||
| Group II—MTAP with UI | Group III—Ca(OH)2 with LAI | 1.200 | 0.002*S | |
| Group IV—MTAP with LAI | 0.250 | 0.865 | ||
| Group III—Ca(OH)2 with LAI | Group IV—MTAP with LAI | −0.950 | 0.021*S | |
| Total | Group I—Ca(OH)2 with UI | Group II—MTAP with UI | −0.550 | 0.126 |
| Group III—Ca(OH)2 with LAI | 0.300 | 0.621 | ||
| Group IV—MTAP with LAI | −0.350 | 0.494 | ||
| Group II—MTAP with UI | Group III—Ca(OH)2 with LAI | 0.850 | 0.005*S | |
| Group IV—MTAP with LAI | 0.200 | 0.850 | ||
| Group III—Ca(OH)2 with LAI | Group IV—MTAP with LAI | −0.650* | 0.050*S | |
*S, significant; **HS, highly significant; post hoc Tukey test
Discussion
Calcium hydroxide [Ca(OH)2], when in direct contact, eliminates various microbes that are frequently seen in infected root canals due to their high alkalinity.9 Also, it inactivates lipopolysaccharides, thereby assisting in periapical tissue repair.10 A single antibiotic is not sufficient to eradicate the polymicrobial flora, so a combination of antibiotics is required to address the diverse microflora harbored in root canal infections. Hoshino et al. reported that a mixture of ciprofloxacin, metronidazole, and minocycline, all three at concentrations of 25 µg/mL (0.0025%), was sufficient enough to disinfect infected root dentine in vitro.3 Sato et al., stated that this mixture, each at a concentration of 50 µg/mL (0.005%) when used was able to disinfect infected root canals.4 Hence in the current investigation, an amalgamation of ciprofloxacin, metronidazole, and clindamycin was taken in a ratio of 1:1:1, ground into a fine powder, and combined with propylene glycol vehicle.
In clinical practice, irrigant combinations are frequently used to overcome the drawbacks that are encountered with single irrigant usage. Therefore, in the current study, canals were irrigated with both NaOCl and EDTA. Also, in the current study, various factors like concentration, type, volume, and temperature of all the irrigants used were standardized in all groups to omit any interfering factors.
Ultrasonic irrigation (UI) is centered on the principle of energy transmission from an ultrasonic instrument to the irrigating solution that is present inside the root canal.11,12 Numerous studies revealed that both in vital and necrotic teeth, 1 minute of continuous UI resulted in noticeably cleaner canals and isthmi.13,14 Hence, UI was considered in the present study.
Lasers activate irrigants by the transmission of pulsed energy. Erbium-doped yttrium-aluminum-garnet and Er,Cr:YSGG laser light activated irrigation has been found to be more effective than manual irrigation or passive ultrasonic irrigation (PUI) in removing dentinal debris and smear layer.15 The present research utilized Er,Cr:YSGG laser light at sub-ablative settings, which prevents damage to the root canal wall, thereby avoiding ledge formation. The laser tip is kept constant during the emission of laser rays while inserted centrally in the root canal without contacting the root canal walls.
In the present study, intracanal medicaments were better removed in the coronal and middle thirds compared to the apical third. Similar findings were reported by Kourti and Pantelidou, where a significant amount of intracanal medicament was removed in the coronal and middle thirds than the apical third when manual, EndoVac, PUI, and laser were tested.16
In the current study, the LAI protocol's effectiveness was superior to UI. It can be attributed to the fact that LAI is centered upon the concept of energy transmission that causes transient cavitation in the liquid due to optical breakdown. The apical third has shown greater amounts of residues than the coronal and middle thirds in PUI compared to LAI. Similar kind of results was observed in previous studies by Gorduysus et al. and Jiang et al.17,18 This is due to the accumulation of residues in the apical region, where the canal has a smaller area for the irrigant to be reached, resulting in the lesser volume of irrigant. Added to this, the anatomy of the apical third is complex.
In the present study, when medicaments were compared, Ca(OH)2 was better removed than MTAP from the canals. Similar results were found in the research works conducted by Kenee et al. and Berkhoff et al.19,20 With ultrasonic activation, more residues of MTAP were observed compared to the Ca(OH)2 in the current study. This can be defended by the size of the particle and the vehicle used, which determines the material's consistency that results in penetration into the dentin tubules.
In view of the given possible implications in removing intracanal medicaments from the root canal, the following factors, such as the type of irrigant, irrigation agitation technique, consistency of the intracanal medicament, and the vehicle used for preparing the medicament can be considered. Grasping these fundamental and basic factors is pivotal for clinicians to enhance the effectiveness of irrigant agitation systems. Also, it serves as a stimulating guide for future research works on endodontic debridement.
Conclusion
Laser-activated irrigation (LAI) was superior to UI in removing Ca(OH)2 and MTAP. Ca(OH)2 was better removed than MTAP, irrespective of the technique used. However, neither of the irrigation techniques completely removed the intracanal medicament from the root canals.
Footnotes
Source of support: Nil
Conflict of interest: None
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