In-vitro efficacy of Er:YAG laser-activated irrigation versus photon-induced photoacoustic streaming (PIPS) irrigation for smear layer removal: A Scanning Electron Microscopy Study

doi:10.21203/rs.3.rs-4796522/v1

Purpose

to microscopically examine the effect of Er:YAG and Er,Cr:YSGG lasers agitation techniques on smear layer removing-capacity of NaOCl intracanal at the apical, middle, and coronal regions of root canal walls.

Methods

Eighteen freshly extracted human single-canal anterior dentitions were chosen for this study. After the root canals mechanically prepared to size X4, 0.06 taper byrotary files of ProTaper Next® system, they were randomly categorized into three equal groups (6 teeth each); syringe/needle- and Er,:YAG and Er,Cr:YSGG laser-activated groups. Lasers were operated at subablative level. For microscopic assessment, samples were longitudinally hemi-sectioned. Kruskal-Wallis and Mann-Whitney tests were utilized to statistically analyze the collected data.

Results

Laser-activated groups presented significant lower smear layer score values than that of syringe/needle activated group.

Conclusion

Erbium laser-activated irrigation technique has a favorable impact on agitation NaOCl root canal irrigant enhancing the cleaning procedure of root canal system.

Er:YAG laser

Er

Cr:YSGG laser

PIPS technique

Radial firing tip

smear layer removal

root canal irrigation

Failed endodontic procedures are chiefly occurred due to an unavoidable attachment of the root canal bacterial infection to the radicular dentin wall during or after endodontic treatment or are arisen because of incompleteness of the root canal filling inciting re-infecting of root canal system [1]. Thus, the principal purposes of root canal therapy are amplifying the eradication of root canal microbes and debris and obturating the clean radicular space tight three-dimensional endodontic filling [2].

The microscopic inspection revealed that instrumentation of root canal dentin leaves more than a fifth of the radicular wall without preparation. In addition, endodontic mechanical preparation establishes inevitable unfavorable coating of a mixture of dentin chips, pulpal remnants, and bacterial microorganism called smear layer which restrains the completion of cleaning of the entire root canal system [3].

In fact, a root canal irrigation step is mandatory for accomplishing successful endodontic treatment [4]. Intracanal irrigants plays a pivotal indispensable role in cleansing and disinfecting the root canal system [5]. They can eradicate the residual pathogens present on non-instrumented dentin wall and remove smear layer that blocking the infected dentinal tubules for achieving optimal sterilization of radicular structures and maximizing the sealability and adaptability properties of endodontic filling materials [4].

Currently, a variety of chemical and natural solutions are used to irrigate the root canal system. Sodium hypochlorite with concentrations of 1-5.25% are considered the irrigant of choice for effectual cleaning and decontaminating of the root canal dentin [4]. NaOCl irrigating solutions have a transcendent potency to dissolve necrotic pulpal remnants and the organic constructions of the smear layer [4].

Because of complexity of radicular morphology, irrigating solutions cannot generally be delivered to regions of root canal system beyond the central body of the root canal without agitation modality [6]. So, lateral canals, canal fins, cul-de-sacs, and canal isthmi are highly missed during intracanal irrigation application [6]. Consequently, enduring root canal bacterial strains and their by-product, and organic pulpal fragments standing at inaccessible unprepared zones of root canal system can unquestionably be a source persistent pulpal and periradicular pain and inflammation [7]. At present, agitation of intra-canal irrigating solution can be executed by manual and machine-assisted means [8].

The literature reported laser irradiation has superior impact on smear layer removal and dentin wall disinfection during endodontic treatment [9]. Red and near infrared low-intensity lasers can induce root canal bacterial eradication in combination with particular photosensitizers [10]. Also, high-power lasers are recruited to exterminate intracanal pathogens with / without applying root canal irrigating solutions [11].

Fiber-delivered near infrared lasers have been firstly agitate the root canal irrigation solutions using an end-irradiating optical fiber. This technique is called conventional laser-assisted irrigation technique (LAI). Difficulty to direct the laser beam laterally on the radicular dentin surface, forced manufacturers make a modification laser fiber optics. A technology of laser radial-fiber tip (RFT) allows more lateral laser emission improving the agitation of intracanal irrigating solution as well as efficiency of optical disinfection [11].

Er:YAG (2940 nm) and Er,Cr:YSGG (2780 nm) lasers which are present in medium infrared zone of electromagnetic spectrum exhibited that they are highly absorbed by water compared to other dental lasers [12]. Therefore, they are used for soft and hard tissue dental application, in addition, they can powerfully activate water-based root canal irrigating solutions [13, 14].

Super short pulsed (SPP) Er:YAG laser (i.e. pulse width is measured in microsecond) generates superior energetic irradiation; photon-induced photoacoustic streaming (PIPS) to a target; intracanal irrigant even it is operated at very low energy. During PIPS technique, Er:YAG laser is delivered at subablative level though unique tapered and stripped tip positioned at pulp chamber permitting photoacoustic and photomechanical events to generate shock waves. Decontamination and cleaning of PIPS technique are achieved without heat generation or cause thermal damage, if laser parameters are properly being set [15].

Aim of the study

The aim of this study was to microscopically compare smear layer removal after the final NaOCl irrigant was activated with Er,Cr:YSGG laser using radial-firing tip and Er:YAG laser using photon-induced photoacoustic streaming (PIPS) tip. The null hypothesis was that there are no differences in smear layer elimination with using different Erbium lasers for agitation NaOCl root canal irrigating solutions.

Ethical approval:

The protocol used in this present study was approved by the Scientific Research Ethics Committee of National Institute of Laser Enhanced Sciences (NILES) Cairo University, Egypt (reference no.: NILES-EC-CU 23/9/21 [in]).

Sample size calculation:

Sample size calculation was accomplished by R statistical package, version 3.3.1 (21-0-2016) copyright (C) 2016, in accordance to (Bolhari B. et al., 2014). ⁽¹⁶⁾Six samples for each group was an adequate size, with an 80% power and a significance level of 0.05.

Samples’ selection, grouping and preparation:

A total eighteen freshly extracted human single-rooted teeth were randomly nominated for this study. All teeth were coronally free from any defect or restoration. In addition, each tooth root had closed apex and single canal with no radicular resorption or calcification. The apical curvature of roots of the selected teeth was less than twenty degrees.

Teeth surface debris was first removed with ultrasonic scaler and cleaned with tap water. Then the teeth were kept in a sealed container filled with sodium chloride 0.9 W/V (normal saline).

Root canal therapy of all teeth was stared with standard access cavity preparation of each tooth. These prepared cavities were performed by using a high-speed contra-angle handpiece connected to a tapered diamond bur.Next a size#10, sterile, stainless-steel, hand K-file was inserted inside root canal space for measuring the apical potency. When the k-file tip searched to the same level of apical foramen, the apical potency was determined.

Access cavities to root canal were created using tapered diamond bar under copious water spray. ⁽²²⁾ The apical patency of each was checked by sterile, stainless-steel hand K-file (size#10). ProTaper Next® files (Dentsply Maillefer, New York, USA) were used to mechanically prepared the root canals at torque of 2N/m and rotational speed of 300 rpm. ⁽¹⁷⁾ All canals were enlarged to size# x4 ProTaper Next® files, ⁽¹⁷⁾ and all were instrumented 0.5 mm shorter than the length of file used for checking the root canal apical potency. A NiTi rotary file was avoided after preparing three root canal. ⁽¹⁸⁾

Subsequently, teeth were randomly categorized into two groups (6 teeth in each) in accordance to the method of intacanal activation technique; conventional syringe/needle irrigation technique (group I) using side-vented needle (Monoject, Sherwood Medical, Switzerland), Er,YAG laser (2940 nm) (LightWalker, Fotona, Ljubljana, Sloveni) (group II) using PIPS tip and, Er,Cr:YSGG laser (2780 nm) (Waterlase iPlus, Biolase Technology, Irvine, CA, USA) (group III) using RFT.

Each root canal was irrigated with 5 ml of 5% NaOCl solution. The volume of root canal irrigant was gradually applied for one minute.

For proper conventional syringe/needle irrigation technique, the side-vented needle was inserted into the root canal up to 1 mm short of its working length.

Er,Cr:YSGG (2780 nm) laser beam settings was set at energy of 25 mJ, pulse width of 60 μs, and pulse frequency of 50 Hz, for total activation time of 60 sec. (three cycles, each for 20 sec.) with no water and air sprays. Irradiation of Er,Cr:YSGG (2780 nm) laser was delivered through radial firing tip (RFT) (Waterlase laser tip RF3-21, Biolase, Technology, Irvine, CA, USA) with a diameter of 415 μm, a length of 21 mm and calibration factor of 0.85. The radial firing tip (RFT) was introduced into NaOCl-filled root canal 2 mm short of working length before laser beam was irradiated. During laser activation the radial firing tip (RFT) was spirally moved in a speed of 1 mm/s towards the tooth crown.

Er:YAG laser device was employed. The laser operated at pulse energy of 20 mJ, pulse width of 50 μs, pulse frequency of 15 Hz, for total activation time of 60 sec. (three cycles, each for 20 sec.), ⁽³⁰⁾ with no water and air sprays. Irradiation of Er,Cr:YSGG (2780 nm) laser was delivered through radial stripped PIPS tip with a diameter of 400 μm and a length of 11 mm (PIPS 400/11, Fotona, Ljubljana, Sloveni). PIPS tip was connected with a 90 handpiece before its placement inside the coronal pulp chamber at the entrance of the canal orifice.

At the end, the root canals were dried with absorbent paper point ProTaper Next® size#x4 (Dentsply Maillefer, New York, USA).

SEM evaluation:

A single absorbent paper point size# X4 was accurately filled the root canal during samples’ sectioning procedure.

The longitudinal hemi-sectioning of samples was started on the proximal aspects of the coronal portion parallel to long axis of tooth root.

A low-speed diamond water-cooled diamond saw (Isomet 4000, Buehler Ltd, Lake Bluff, IL, USA) was utilized to implement the precise samples’ sectioning. ^{(13, 14)}

The microscopic analysis was conducted with environmental scanning electron microscope ESEM (FEI Quanta 250 FEG, Berlin, Germany) with an electron accelerating voltage of 20 KV at a standard magnification of ×2000. ⁽¹⁹⁾

The coronal, middle and apical thirds of dentinal wall of the sections were microscopically captured, then studied for assessing the smear layer eradicating capability and the presence of dentinal tubules’ opening by two expertise qualified inspectors, individually. ⁽²⁰⁾

Evaluation of ESEM images was followed the 5- point scoring method of (Hülsmann M. et al., 1997).⁽²¹⁾The scores were as follows- Score 1: no smear layer was noticed on the dentin wall and all dentinal tubules orifices were evidently opened; Score 2: miniscule aggregate of smear layer was noticed on the dentin wall, besides many dentinal tubule were unlocked; Score 3: homogenous smear layer was visibly covered the dentin wall with few open dentinal tubules were seen; Score 4: homogenous smear layer was the completely shielded nearly the entire dentinal wall, and all dentinal tubules were blocked; Score 5: a heavy, heterogonous smear layer covering the entire dentinal wall of root canal, and all dentinal tubules were blocked. ⁽²¹⁾

Statistical analysis

The samples’ recorded scores were analyzed using SPSS (Statistical Packages for the Social Sciences 26.0, IBM, Armonk, NY, USA). Cohen’s kappa coefficient test was used to check inter- & intra-inspectors’ reliability. Moreover, Kolmogorov-Smirnov and Shapiro-Wilk tests recruited to determine the study data normality. Furthermore, Kruskal-Wallis nonparametric analysis of variance, followed by Mann-Whitney test were executed to statistically evaluate the numeric data of the tested groups (different activating methods) based on the studied root segment, regarding the level of statistical significance was set at 0.05.

The results of smear layer evaluation showed that both erbium laser-activated irrigation technique groups; group II (Er:YAG 2940-nm laser irrigation technique) and group III (Er,Cr:YSGG 2780-nm laser irrigation technique) recorded significant lower value than that of group I (conventional syringe/needle irrigation technique) at coronal third of root canal dentin. Moreover, group III (Er,Cr:YSGG 2780-nm laser irrigation technique) recorded significant lower value (2.333±0.817) than that of group I (conventional syringe/needle irrigation technique) (3.333±0.516) at middle third of root canal dentin. Furthermore, group II (Er:YAG 2940-nm laser irrigation technique) recorded significant lower value (2.667±0.517) than that of group I (conventional syringe/needle irrigation technique) (4.333±0.516). There was no significant difference between both erbium laser-activated irrigation technique groups; group II (Er:YAG 2940-nm laser irrigation technique) and group III (Er,Cr:YSGG 2780-nm laser irrigation technique) recorded at different root thirds (see table 1 & 2, and figure 1).

Regarding the location of the root thirds, the results of smear layer evaluation presented the were significant different between coronal, middle, and apical third when they were exposed to conventional syringe/needle irrigation technique. While, there was no statistical differences between them when they were exposed to erbium lasers (Er:YAG 2940 nm & Er,Cr:YSGG 2780 nm) irrigation techniques (see table 3 & 4 and figure 2).

Table (1): The mean, standard deviation (SD) and kruskal-Wallis statistics of smear layer scores of different groups; conventional, Er:YAG-laser-activated and Er,Cr:YSG-laser activated irrigation techniques at coronal, middle, and apical thirds

Root segments	Groups (Irrigation technique)	N	Mean	±SD	Mean Rank of score	Kruskal-Wallis statistics
Root segments	Groups (Irrigation technique)	N	Mean	±SD	Mean Rank of score	Kruskal-Wallis H	Degree of freedom	P-value
Coronal	Conventional	6	3.167	±0.408	14.67	10.324	2	0.006*
	Er:YAG	6	1.833	±0.983	8.17
	Er,Cr:YSGG	6	1.333	±0.516	5.67
Middle	Conventional	6	3.333	±0.516	13.83	13.728	2	0.016*
	Er:YAG	6	2.444	±1.033	5.67
	Er,Cr:YSGG	6	2.333	±0.817	9
Apical	Conventional	6	4.333	±0.516	14	7.726	2	0.021*
	Er:YAG	6	2.667	±0.516	5.83
	Er,Cr:YSGG	6	3	±1.673	8.67

Table (2): Man-Whiteny statistics of smear layer scores of different groups; conventional, Er:YAG-laser-activated and Er,Cr:YSG-laser activated rrigation techniques at coronal, middle, and apical thirds.

Root segments	Area of comparison (Irrigation techniques)		N	Mean Rank	Sum of Ranks	Mann-Whiteny U	Wilcoxon W	Z value	P-value
Coronal	Conventional-Er:YAG	Conventional	6	8.67	52	5	26	-2.342	0.019*
		Er:YAG	6	4.33	26
	Conventional- Er,Cr:YSGG	Conventional	6	9.5	57	0.000	21	-3.052	0.002*
		Er,Cr:YSGG	6	3.5	21
	Er:YAG- Er,Cr:YSGG	Er:YAG	6	7.33	34	13	34	-0.903	0.367
		Er,Cr:YSGG	6	5.67	44
Middle	Conventional-Er:YAG	Conventional	6	8.17	49	6	29	-1.915	0.056
		Er:YAG	6	4.83	29
	Conventional-Er,Cr:YSGG	Conventional	6	9.17	55	2	23	-2.687	0.007*
		Er,Cr:YSGG	6	3.83	23
	Er:YAG – Er,Cr:YSGG	Er:YAG	6	7.67	46	11	32	-1.211	0.226
		Er,Cr:YSGG	6	5.33	32
Apical	Conventional-Er:YAG	Conventional	6	9.5	57	0.000	21	-3	0.003*
		Er:YAG	6	3.5	21
	Conventional-Er,Cr:YSGG	Conventional	6	8	48	9	30	-1.554	0.120
		Er,Cr:YSGG	6	5	30
	Er:YAG – Er,Cr:YSGG	Er:YAG	6	5.83	35	14	35	-0.668	0.504
		Er,Cr:YSGG	6	7.17	43

Table (3): The mean, standard deviation (SD) and kruskal-Wallis statistics of smear layer scores recorded at different root segments; coronal, middle and apical root thirds after they were exposed to conventional, Er:YAG-laser-activated and Er,Cr:YSG-laser activated irrigation techniques

Group (Irrigation technique)	Root segment	N	Mean	±SD	Mean Rank of score	Kruskal-Wallis statistics
Group (Irrigation technique)	Root segment	N	Mean	±SD	Mean Rank of score	Kruskal-Wallis H	Degree of freedom	P-value
Conventional	Coronal	6	3.167	±0.408	6.33	9.888	2	0.007*
	Middle	6	3.333	±0.516	7.67
	Apical	6	4.333	±0.516	14.5
Er:YAG	Coronal	6	1.833	±0.983	7.17	2.368	2	0.306
	Middle	6	2.333	±1.033	10
	Apical	6	2.667	±0.516	11.33
Er,Cr:YSGG	Coronal	6	1.333	±0.516	7.17	3.781	2	0.151
	Middle	6	1.667	±0.817	8.75
	Apical	6	3	±1.673	12.58

Table (4): Man-Whiteny statistics of smear layer scores recorded at different root segments; coronal, middle and apical root thirds after they were exposed to conventional, Er:YAG-laser-activated and Er,Cr:YSG-laser activated irrigation techniques

Group (Irrigation technique)	Area of comparison (Root segments)		N	Mean Rank	Sum of Ranks	Mann-Whiteny U	Wilcoxon W	Z-value	P-value
Conventional	Coronal-Middle	Coronal	6	6	36	15	36	-0.638	0.523
		Middle	6	7	42
	Coronal-Apical	Coronal	6	3.83	23	2	23	-2.768	0.006*
		Apical	6	9.17	55
	Middle-Apical	Middle	6	4.17	25	4	25	-2.447	0.014*
		Apical	6	8.83	53
Er:YAG	Coronal-Middle	Coronal	6	5.67	34	13	34	-0.891	0.373
		Middle	6	7.33	44
	Coronal-Apical	Coronal	6	5	30	9	30	-1.563	0.118
		Apical	6	8	48
	Middle-Apical	Middle	6	6.17	37	16	37	-0.383	0.702
		Apical	6	6.83	41
Er,Cr:YSGG	Coronal-Middle	Coronal	6	5.83	35	14	35	-0.73	0.465
		Middle	6	7.17	43
	Coronal-Apical	Coronal	6	4.83	29	8	29	-1.716	0.086
		Apical	6	8.17	49
	Middle-Apical	Middle	6	5.08	30.5	9.5	30.5	-1.419	0.156
		Apical	6	7.92	47.5

Unsuccessful endodontic treatments are occurred due to presence of bacterial infection on the radicular dentin wall or re-infecting of root canal system because of improper endodontic obturation. Thus, the root canal therapy purposes are the complete eradication of root canal microbes and debris and comprehensive 3-diminsional obturating of the root canal space. ⁽²⁾

Instrumentation of root canal dentin leaves more than a fifth of the radicular wall without preparation and creates smear layer covering the instrumented dentin areas. ⁽³⁾

Consequently, enduring root canal bacterial strains and their by-product, and organic pulpal fragments present within smear layer and standing at inaccessible unprepared zones of root canal system can unquestionably be a source persistent pulpal and periradicular pain and inflammation. ⁽⁷⁾

Root canal irrigants such as NaOCl can effectual cleaning and decontaminating of the root canal dentin. ⁽⁴⁾ However, they cannot be delivered to regions of root canal system beyond the central body of the root canal without agitation modality. ⁽⁶⁾

Agitation of intra-canal irrigating solution can be executed by manual and machine-assisted means. ⁽⁸⁾

Er:YAG (2940 nm) and Er,Cr:YSGG (2780 nm) lasers which are present in medium infrared zone of electromagnetic spectrum exhibited powerful efficacy to activate water-based root canal irrigating solutions. ^{(13, 14)}

Actually, few studies had been carried out to compare between both erbium lasers; Er:YAG (2940 nm) and Er,Cr:YSGG (2780 nm) in agitation of NaOCl root canal in order to eradicate smear layer from root canal dentin walls especially when both laser types were operated for the same time. Consequently, this study aimed to microscopically assess the smear layer removal capacity from the root canal dentin after the final NaOCl irrigant was activated with Er,Cr:YSGG laser using radial-firing tip and Er:YAG laser using photon-induced photoacoustic streaming (PIPS) tip.

For achieving high standardization of the study, selection of tested teeth, their mechanical preparation, volume of root-canal irrigating solution and total irrigation and irradiation time were standardized for each root canal examined in this study. ⁽²⁰⁾ Choosing of straight or minimal curved (less than 20°) root canal reduced the risk of breakage laser fiber tip during insertion and application. ⁽²⁰⁾

Widening the root canal till size# x4 accomplished appropriate insertion and application of laser fiber tip as well as flushing and diffusion of NaOCl root canal irrigating solution and kept the root canal save from apical over preparation risk and other intracanal iatrogenic errors. ⁽²²⁾

Using of rotary files three times only ensured the sharpness of file during root canal preparation and minimized the risk of being inside the root canal system. ⁽¹⁸⁾

Both erbium lasers were operated at subablative photon energy settings to avoid potential unwanted over preparation of root canal wall and unfavorable reversible periiradicular impairment because of inducing higher thermal laser/irrigant interaction. ⁽²³⁾

Radial-firing and PIPS tips were employed to apply laser energy directly to lateral sides of root canal wall and space increasing the surface area of irradiate root canal irrigants and root dentin and enhancing the agitation and efficacy of root canal irrigation technique. ⁽²⁴⁾

Utilizing of ESEM for evaluating the smear layer removing-capacity at a magnification of x2000 was efficacious to capture dentin root at coronal, middle, & apical one-thirds of root canal. ^{(34, 35, 36, 37, 38)}^, although its samples’ preparation method was not a conservative procedure. ⁽²⁰⁾

The longitudinal hemi-sectioning of specimen was carried out by low-speed precision cutting saw for reducing the specimen’s distortion during its preparation for microscopic examination.

Independent evaluation of smear layer scores of the specimens by two well-trained qualified raters amplifying the results reliability and preventing the human bias. ⁽²⁰⁾

Based on the statistical analysis of the recorded date in this study, both erbium laser-activated irrigation technique groups; group II (Er:YAG 2940-nm laser irrigation technique) and group III (Er,Cr:YSGG 2780-nm laser irrigation technique) recorded significant lower value than that of group I (conventional syringe/needle irrigation technique) at coronal third of root canal dentin. The finding of reflected that erbium lasers had superior smear layer cleaning capability than that of conventional syringe/needle technique. The similar results were reported in several previous studies such as (George R. et al., 2008;⁽²⁵⁾DiVito E. et al., 2011;⁽²⁶⁾ DiVito E. et al., 2012;⁽²⁷⁾Sabari M., 2012;⁽²⁸⁾ Murugesan M. et al., 2013;⁽²⁹⁾ Akyuz E. et al., 2015;⁽³⁰⁾ Madhusudhana K. et al., 2016;⁽³¹⁾ Nasher R. et al., 2016;⁽³²⁾ Sudhakar V., 2017;⁽³³⁾Wang X. et al. 2017;⁽³⁴⁾Korkut E. et al., 2018;⁽³⁵⁾Montero-Miralles P. et al., 2018;⁽³⁶⁾ Ozbay Y. and Erdemir A., 2018;⁽³⁷⁾ Sari F. et al., 2018;⁽³⁸⁾ Sippus J. et al., 2019;⁽³⁹⁾ Wu L. et al., 2021;⁽⁴⁰⁾Abdelgawad L. et al., 2022a;⁽¹³⁾ Abdelgawad L. et al., 2022b;⁽¹⁴⁾ Abdelgawad L. et al., 2022c;⁽⁴¹⁾ Obeid M. et al., 2022 ⁽⁴²⁾).

These findings may be credited to that the physical impact of employing photon energy of pulsed erbium laser on NaOCl root canal irrigant leading to cavitation and shock waves. Photomechanical influence intensifying the shearing stresses on root canal system and irrigant improving the cleaning root canals. ⁽⁴³⁾

Under the conditions of this study, irradiating NaOCl root canal irrigant with erbium lasers improved the eradication of smear layer from the entire root canal dentin. Thus, the examined laser protocols can be clinically aid the elimination smear layer during a root canal therapy.

Human Ethics and Consent:

Human Ethics and Consent to Participate declarations: not applicable

Consent to Participate declaration

No human individuals were participated in this study.

Consent for publication

No human individuals were participated in this study.

The ethics declaration

This study protocol was reviewed and approved by the Scientific Research Ethics Committee of National Institute of Laser Enhanced Sciences (NILES) Cairo University, Egypt, approval number (NILES-EC-CU 23/9/21 [in]).

Funding Declaration

The authors did not receive support from any organization for the submitted work

Barbosa-Ribeiro, Marlos, et al. "Antibiotic Resistance Profile of Clinical Strains of Enterococci from Secondary/Persistent Endodontic Infections: What do We Know? A Systematic Review of Clinical Studies." Journal of Endodontics (2024).
Peters, Ove A., Christine I. Peters, and Bettina Basrani. "Cleaning and shaping of the root canal system." Cohen's Pathway of the Pulp ed. 12, Elsevier, St. Louis, Missauri (2021): 236-303.
Jhajharia, Kapil, et al. "Biofilm in endodontics: a review." Journal of International Society of Preventive & Community Dentistry 5.1 (2015): 1.‏
Shravya, S., Roopa R. Nadig, and Veena S. Pai. "Root Canal Irrigant Combining Salvadora Persica with Sodium Hypochlorite – Antimicrobial, Tissue Dissolution ,Chelating Action & Changes in Ca/P Of Root Dentin :in Vitro Study." International Journal of Scientific Research 9.8 (2020)
Singh, Mukund, et al. "The Effect of Four Commonly Used Root Canal Irrigants on the Removal of Smear Layer: An In-Vitro Scanning Electron Microscope Study." Annals of the Romanian Society for Cell Biology (2021): 10611-10617.‏
Mancini, Manuele, et al. "Removal of Accumulated Hard Tissue Debris (AHTD) from Root Canals with an Electric Current Device: A MicroCT Preliminary Report." Applied Sciences 12.4 (2022): 1969.
Yao, Yichen, et al. "In vitro and in vivo research of atmosphere pressure nonequilibrium plasmas on root canal disinfection: implication for alternative strategy for irrigation." Clinical Oral Investigations 25.10 (2021): 5833-5842.
Krongbaramee, Tadkamol, et al. "Synergistic effect of manual dynamic agitation and ethylenediaminetetraacetic acid containing 0.25% cetrimide on smear layer removal: An in vitro study." Saudi Endodontic Journal 10.3 (2020): 265.
Kaur, Maninder, et al. "Comparative evaluation of smear layer removal by using different irrigant activation techniques: An in vitro scanning electron microscopic study." Journal of Conservative Dentistry and Endodontics 27.3 (2024): 257-261.
Yamaguchi, Yohei, et al. "Effect of Laser Irradiation Modes and Photosensitizer Types on Antimicrobial Photodynamic Therapy (aPDT) for Streptococcus sobrinus in the Crown Dentin of Bovine Teeth: An Experimental In Vitro Study." Dentistry Journal 12.3 (2024): 59.
Olivi, Giovanni and Matteo Olivi. "Conventional Laser Endodontics." Lasers in Endodontics. Springer, Cham, 2016. 111-143.
Olivi, Giovanni, and Roeland JG De Moor. "Laser-Activated Irrigation (LAI)." Lasers in Endodontics. Springer, Cham, 2016. 193-217.
Abdelgawad, Latifa Mohamed, et al. "Effect Of Agitation Of Salvadora Persica Extract And Sodium Hypochlorite Final Irrigating Solutions With Er, Cr: YSGG-Laser Using RadialFiring Tips On Removal Of Smear Layer: A Scanning Electron Microscopic Evaluation." NeuroQuantology 20.13 (2022): 388.
Abdelgawad, Latifa Mohamed, et al. "Influence Of Photon-Initiated Photoacoustic Streaming (Pips) Laser-Activation Method On The Efficiency Of Salvadora Persica Extract And Sodium Hypochloride Final Irrigating Solutions In Removing Smear Layer: A Scanning Electron Microscopy Analysis." NeuroQuantology 20.14 (2022): 194.
Olivi, Giovanni, and Enrico E. DiVito. "Advanced Laser-Activated Irrigation: PIPS TM Technique and Clinical Protocols." Lasers in endodontics: Scientific background and clinical applications (2016): 219-291.
Bolhari, Behnam, et al. "Efficacy of Er, Cr: YSGG laser in removing smear layer and debris with two different output powers." Photomedicine and laser surgery 32.10 (2014): 527-532.
Abd-Elgawad, Reem Adel, and Dalia Mukhtar Fayyad. "Comparative Evaluation of Smear Layer Removal, Calcium Ions Loss and Dentin Microhardness After Different Final Irrigation Solutions." Egyptian Dental Journal 63.4-October (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics) (2017): 3551-3562.‏
Elemam, Ranya Faraj, José A. Capelas, and Manuel F. Vieira. "Effect of repeated use on topographical features of ProTaper Next Endodontic Rotary File." (2016).‏
Mohamed, Nada F., Mohsen Nour El Dein, and Heba Abdelkafy. "Efficacy of Apple Vinegar as Root Canal Irrigant in Removing Smear Layer in Curved Canals Using EndoVac Irrigation System." Al-Azhar Dental Journal for Girls 9.1 (2022): 73-81.‏
Alakshar, Asmaa, Abdul Rahman Mohammed Saleh, and Mehmet Omer Gorduysus. "Debris and smear layer removal from oval root canals comparing XP-Endo Finisher, EndoActivator, and manual irrigation: A SEM evaluation." European Journal of Dentistry 14.04 (2020): 626-633.‏
Hülsmann, Michael, Claudia Rümmelin, and Frank Schäfers. "Root canal cleanliness after preparation with different endodontic handpieces and hand instruments: a comparative SEM investigation." Journal of endodontics 23.5 (1997): 301-306.‏
Haupt, Franziska, et al. "Effectiveness of different activated irrigation techniques on debris and smear layer removal from curved root canals: a SEM evaluation." Australian Endodontic Journal 46.1 (2020): 40-46.‏
Keskin, Gül, and Mehmet Çiloğlu. "Efficacy of antimicrobial photodynamic therapy and Er, Cr: YSGG laser-activated irrigation on dentinal tubule penetration of MTA-based root canal sealer: A confocal microscopy study." Photodiagnosis and Photodynamic Therapy 36 (2021): 102584.‏
Verdaasdonk, Rudolf M. "Medical lasers: fundamentals and applications." Advances in Lasers and Applications. CRC Press, 2021. 181-226.‏
George, Roy, Ian A. Meyers, and Laurence J. Walsh. "Laser activation of endodontic irrigants with improved conical laser fiber tips for removing smear layer in the apical third of the root canal." Journal of endodontics 34.12 (2008): 1524-1527.‏
DiVito, Enrico E., Mark P. Colonna, and G. Olivi. "The photoacoustic efficacy of an Er: YAG laser with radial and stripped tips on root canal dentin walls: an SEM evaluation." J Laser Dent 19.1 (2011): 156-161.‏
DiVito, Enrico, Ove A. Peters, and G. Olivi. "Effectiveness of the erbium: YAG laser and new design radial and stripped tips in removing the smear layer after root canal instrumentation." Lasers in medical science 27.2 (2012): 273-280.‏
Sabari, M. Effectiveness of Newer Tip Design of Laser in Removing the Smear Layer at the Apical Third of Curved Root Canals: An Ex Vivo study. Diss. Ragas Dental College and Hospital, Chennai, 2012.‏
Murugesan, M. Sabari, et al. "Efficacy of Er, Cr: YSGG Laser with Conical Tip Design in Smear Layer Removal at the Apical Third of Curved Root Canals." International Journal of Laser Dentistry 3.2 (2013): 55.‏
Akyuz Ekim, Sefika Nur, and Ali Erdemir. "Comparison of different irrigation activation techniques on smear layer removal: an in vitro study." Microscopy research and technique 78.3 (2015): 230-239.‏
Madhusudhana, Koppolu, et al. "Effect of endoactivator and Er, Cr: YSGG laser irradiation in removing the smear layer after root canal instrumentation: An in vitro study." Journal of Dr. NTR University of Health Sciences 5.1 (2016): 24.‏
Nasher, Riman, Rene Franzen, and Norbert Gutknecht. "The effectiveness of the Erbium: Yttrium aluminum garnet PIPS technique in comparison to different chemical solutions in removing the endodontic smear layer—an in vitro profilometric study." Lasers in medical science 31.9 (2016): 1871-1882.‏
Sudhakar, V. Comparison of Smear Layer Removal Ability Using Qmix and MCP Irrigating Solutions by Er: Yag Laser Activation: A Scanning Electron Microscope Analysis. Diss. Ragas Dental College & Hospital, Chennai, 2017.‏
Wang, Xiaoli, et al. "Effect of laser-activated irrigations on smear layer removal from the root canal wall." Photomedicine and laser surgery 35.12 (2017): 688-694.‏
Korkut, Emre, et al. "Antibacterial and smear layer removal efficacy of Er: YAG laser irradiation by photon-induced photoacoustic streaming in primary molar root canals: a preliminary study." Photomedicine and laser surgery 36.9 (2018): 480-486.‏
Montero-Miralles, Paloma, et al. "Comparative study of debris and smear layer removal with EDTA and Er, Cr: YSGG laser." Journal of clinical and experimental dentistry 10.6 (2018): e598.‏
Ozbay, Yagiz, and Ali Erdemir. "Effect of several laser systems on removal of smear layer with a variety of irrigation solutions." Microscopy Research and Technique 81.10 (2018): 1214-1222.‏
Sari, Fatih, et al. "Effect of Combined Use of Photon-Initiated Photoacoustic Streaming and Chitosan on Smear Layer Removal." (2018).‏
Sippus, Jaana, and Norbert Gutknecht. "Deep disinfection and tubular smear layer removal with Er: YAG using photon-induced photoacoustic streaming (PIPS) contra laser-activated irrigation (LAI) technics." Lasers in Dental Science 3.1 (2019): 37-42.‏
Wu, Lixuan, et al. "Effect of Optimized Irrigation With Photon‐Induced Photoacoustic Streaming on Smear Layer Removal, Dentin Microhardness, Attachment Morphology, and Survival of the Stem Cells of Apical Papilla." Lasers in Surgery and Medicine 53.8 (2021): 1105-1112.‏
Abdelgawad, Latifa Mohamed, et al. "Efficacy of Photoinduced Photoacoustic Streaming and Diode Laser Irrigation Techniques on Smear Layer Removal, Sealer Penetration and Push-out Bond Strength." Journal of Lasers in Medical Sciences 13 (2022).‏
Obeid, Maram, Elham Elshaboury, and Raneem Obeid. "A comparative SEM assessment for the ability of PIPS, XP-Finisher and PUI to eliminate smear layer and open dentinal tubules." Egyptian Dental Journal 68.2 (2022): 1907-1916.‏
Nagahashi, Taiji, et al. "Er: YAG laser-induced cavitation can activate irrigation for the removal of intraradicular biofilm." Scientific reports 12.1 (2022): 1-10.

No competing interests reported.

In-vitro efficacy of Er:YAG laser-activated irrigation versus photon-induced photoacoustic streaming (PIPS) irrigation for smear layer removal: A Scanning Electron Microscopy Study

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