Photon-induced Photoacoustic Streaming Research Articles

The effect of different irrigation activation methods on the penetration of the irrigation solution into the dentinal tubules in teeth with calcium hydroxide applied and oval-shaped canals: Confocal laser scanning microscope analysis.

This study aimed to evaluate the efficacy of different irrigation techniques including standard needle irrigation (SNI), passive ultrasonic irrigation (PUI), EndoActivator (EA), XP-Endo Finisher (XPF), photon-induced photoacoustic streaming (PIPS), and shock wave enhanced emission photo-acoustic streaming (SWEEPS) systems on the penetration of irrigation solutions into dentinal tubules in teeth with calcium hydroxide (CH) applied and oval-shaped canals by confocal laser scanning microscope (CLSM). Ninety mandibular incisor teeth with oval-shaped canals were included in this study. After the preparation of teeth using Resiproc Blue R25 (VDW, Munich, Germany) canals were filled with a paste based on CH. The teeth were stored in 100% humidity at a temperature of 37°C for 14 days. According to the irrigation activation systems, the teeth were divided into six groups (n = 15); SNI, PUI, EA, XPF, PIPS, and SWEEPS. In each group, 3 irrigation/activation cycles of 20 s of irrigation and 20 s of activation were performed with the relevant activation method. The root canals were filled with fluorescein sodium (Sigma, Alldrich Co., St. Louis, MO, USA) and activated with the relevant activation method for 30 s. Specimens were sectioned horizontally to 1 ± 0.1 mm at 2, 5, and 8 mm from the apex and then examined under the CLSM. Maximum penetration depth, maximum penetration area and penetration percentage were measured by using Image J software. Data were analyzed using a two-way analysis of variance (ANOVA) and posthoc Tukey tests (p = .05). No difference was found between the activation systems in terms of maximum penetration depth and maximum penetration area of irrigation solutions in the apical section (p > .05). The penetration percentage of irrigation solutions was higher in PUI and PIPS compared with EA and XPF at the apical section (p < .05). No difference was found between SNI, PUI, PIPS, and SWEEPS in terms of the penetration percentage of irrigation solutions in all sections (p > .05). The penetration percentage of irrigation solutions was higher in the middle and coronal sections compared to the apical section in EA and XPF (p < .05). Tubule penetration of irrigation solutions in SNI was similar between sections. The Tubule penetration area of irrigation solutions in PUI, EA, XPF, PIPS, and SWEEPS was lower in the apical section than in the middle and coronal sections. RESEARCH HIGHLIGHTS: The tubule penetration depth and area of the irrigation solutions were similar between the activation systems tested in the apical sections. The Tubule penetration area of irrigation solutions in middle and coronal sections was higher in PUI and PIPS than in SNI.

Phase-locked µPIV analysis of flow dynamics in a simulated root canal with different laser-activated irrigations.

To measure the dynamic characteristics of the flow field in a complex root canal model activated by two laser-activated irrigation (LAI) modalities at different activation energy outputs: photon-induced photoacoustic streaming (PIPS) and microshort pulse (MSP). A phase-locked micro-scale Particle Image Velocimetry (µPIV) system was employed to characterise the temporal variations of LAI-induced velocity fields in the root canal following a single laser pulse. The wall shear stress (WSS) in the lateral root canal was subsequently estimated from the phase-averaged velocity fields. Both PIPS and MSP were able to generate the 'breath mode' of the irrigant current under all tested conditions. The transient irrigation flush in the root canal peaked at speeds close to 6 m/s. However, this intense flushing effect persisted for only about 2000 µs (or 3% of a single laser-pulse activation cycle). For MSP, the maximum WSS magnitude was approximately 3.08 Pa at an activation energy of E = 20 mJ/pulse, rising to 9.01 Pa at E = 50 mJ/pulse. In comparison, PIPS elevated the WSS to 10.63 Pa at E = 20 mJ/pulse. Elevating the activation energy can boost the peak flushing velocity and the maximum WSS, thereby enhancing irrigation efficiency. Given the same activation energy, PIPS outperforms MSP. Additionally, increasing the activation frequency may be an effective strategy to improve irrigation performance further.

Comparation of the effectiveness of conventional needle irrigation and photon-induced photoacoustic streaming with sodium hypochorite in the treatment of teeth with apical periodontitis: a randomized clinical trial

Photon-initiated photoacoustic streaming (PIPS) with an Er: YAG laser has been introduced in root canal treatment to improve irrigation and facilitate the removal of bacteria in the root canal system. This study aimed to compare the antibacterial effectiveness of two different root canal irrigation techniques, conventional needle irrigation (CNI) and PIPS, using 1% sodium hypochlorite (NaOCl), in the treatment of teeth with apical periodontitis. Sixty patients with a total of sixty teeth affected by apical periodontitis were included in this study. The teeth underwent root canal therapy, and after mechanical instrumentation, they were randomly assigned to two groups (n = 30) based on the final irrigation protocol: CNI or PIPS with 1% NaOCl. Bacterial suspensions in the root canals were evaluated using Adenosine 5’-triphosphate (ATP) assay kit after mechanical instrumentation and after final irrigation. Then, a follow-up was conducted after 7 days. The results revealed that final irrigation significantly reduced ATP values in both the CNI and PIPS groups (P < 0.001). The ATP values after final irrigation was greater in the CNI group compared to the PIPS group (P < 0.001). After a 7-day follow-up, percussion tenderness and fistula were significantly resolved in both groups (P < 0.05). A multivariate linear regression model was used to identify the factors that influence post irrigation ATP values. The analysis demonstrated that pre-operative percussion tenderness (P = 0.006), the presence of a fistula (P < 0.001) and the method used in the final irrigation (P < 0.001) had a significant impact on the ATP value after final irrigation. These results indicate that employing PIPS with 1% NaOCl as the final irrigation protocol exhibited superior antibacterial effectiveness and has the potential to enhance clinical outcomes in the treatment of teeth afflicted with apical periodontitis.

In vitro efficacy of Er:YAG laser-activated irrigation versus passive ultrasonic irrigation and sonic-powered irrigation for treating multispecies biofilms in artificial grooves and dentinal tubules: an SEM and CLSM study

BackgroundMultispecies biofilms located in the anatomical intricacies of the root canal system remain the greatest challenge in root canal disinfection. The efficacy of Er:YAG laser-activated irrigation techniques for treating multispecies biofilms in these hard-to-reach areas has not been proved. The objective of this laboratory study was to evaluate the effectiveness of two Er:YAG laser-activated irrigation techniques, namely, photon-induced photoacoustic streaming (PIPS) and shock wave-enhanced emission photoacoustic streaming (SWEEPS), in treating multispecies biofilms within apical artificial grooves and dentinal tubules, in comparison with conventional needle irrigation (CNI), passive ultrasonic irrigation (PUI), and sonic-powered irrigation (EDDY). Two types of multispecies root canal biofilm models were established in combination with two assessment methods using scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) with the aim to obtain more meaningful results.MethodsNinety extracted human single-rooted premolars were chosen for two multispecies biofilm models. Each tooth was longitudinally split into two halves. In the first model, a deep narrow groove was created in the apical segment of the canal wall. After cultivating a mixed bacterial biofilm for 4 weeks, the split halves were reassembled and subjected to five irrigation techniques: CNI, PUI, EDD, PIPS, and SWEEPS. The residual biofilms inside and outside the groove in Model 1 were analyzed using SEM. For Model 2, the specimens were split longitudinally once more to evaluate the percentage of killed bacteria in the dentinal tubules across different canal sections (apical, middle, and coronal thirds) using CLSM. One-way analysis of variance and post hoc multiple comparisons were used to assess the antibiofilm efficacy of the 5 irrigation techniques.ResultsRobust biofilm growth was observed in all negative controls after 4 weeks. In Model 1, within each group, significantly fewer bacteria remained outside the groove than inside the groove (P < 0.05). SWEEPS, PIPS and EDDY had significantly greater biofilm removal efficacy than CNI and PUI, both from the outside and inside the groove (P < 0.05). Although SWEEPS was more effective than both PIPS and EDDY at removing biofilms inside the groove (P < 0.05), there were no significant differences among these methods outside the groove (P > 0.05). In Model 2, SWEEPS and EDDY exhibited superior bacterial killing efficacy within the dentinal tubules, followed by PIPS, PUI, and CNI (P < 0.05).ConclusionEr:YAG laser-activated irrigation techniques, along with EDDY, demonstrated significant antibiofilm efficacy in apical artificial grooves and dentinal tubules, areas that are typically challenging to access.

Extrusion bond strength and disinfection of E. faecalis from canal dentin using synchronized microbubble photodynamic activation and photon-induced photoacoustic streaming.

This study aimed to assess the antimicrobial effectiveness of a new disinfection regimen Curcumin photosensitizer (CP), Synchronized Microbubble Photodynamic Activation (SYMPA), Photon-induced photoacoustic streaming (PIPS), and its impact on the extrusion bond strength (EBS) of root filling material to canal dentin. Root canal treatments of sixty mandibular incisors were performed, and an overnight culture of E. faecalis was cultivated in the BHI medium. A volume of 1 mL was introduced into twenty root canals. All the samples were randomly allocated into 4 groups based on the irrigation used: -Group 1: 2.5% NaOCl+17% EDTA (Control), Group 2: CP+17% EDTA, Group 3: SYMPA+17% EDTA, and Group 4: PIPS+17% EDTA. The viable bacterial count was estimated, and 15 specimens from each group were obturated, followed by sectioning in 1-mm thick slices. The EBS was measured using a universal testing machine, and failure modes were analyzed using a stereomicroscope at 40x magnification. Means and standard deviations (SD) of the survival rate of E. faecalis and EBS of root filling to the dentin were analyzed using ANOVA Tukey multiple comparison t-tests (p=0.05). Group 1 (2.5% NaOCl+17% EDTA) demonstrated the highest survival rate of E. faecalis. Group 3, in which SYMPA+17% EDTA was used to sterilize the canal, unveiled the lowest survival rate (1.55±0.11 CFU/mL). Similarly, the coronal section of Group 3 specimens (8.67±0.43MPa) demonstrated the highest EBS. However, an apical section of Group 1 samples (2.81±0.11MPa) displayed the lowest outcome of bond integrity. Intergroup comparison analysis revealed that Group 4 (PIPS+17% EDTA) and Group 2 (CP+17% EDTA) samples demonstrated comparable values of bond integrity and bacterial survival. Canal disinfection using the synchronized microbubble photodynamic activation (SYMPA) technique proved to be a promising alternative technique in decreasing the count of E. faecalis and improving extrusion bond strength of gutta percha to canal dentin.

Eradication of mature biofilm from the isthmus region using Er, Cr: YSGG Laser as an activator of 2% chlorhexidine gluconate.

Challenges in the root canal system, such as isthmus, may limit the action of endodontic equipment and irrigation solutions, so using laser agitation is recommended to upgrade the removal of microbial biofilm. The objective of this study is to assess the effectiveness of the laser in photon-induced photoacoustic streaming protocol agitation of 2% chlorohexidine gluconate in removing mature biofilm in complex root canal systems. Seventy-five mesial roots of the lower first and second molars were separated and cultivated with Enterococcus faecalis bacteria for 30 days (except for the negative control group samples). The samples were divided into four groups (n=15), one group acted as a positive control, other groups were irrigated with 2% chlorohexidine gluconate, some of them were agitated with a passive ultrasonic device, while the other samples were agitated by an Erbium, chromium-doped yttrium, scandium, gallium, and garnet laser in photon-induced photoacoustic streaming protocol. An atomic force microscope was used as a new method to get the results in the isthmus area; A scanning electron microscope was also used in the study to examine the samples before and after the treatment. Statistical Package for Social Sciences software was used to collect and analyze data, and two-way ANOVA was used to compare the means of the test groups. According to the atomic force microscope and scanning electron microscope analyses, Erbium laser and passive ultrasonic activation groups showed higher antimicrobial efficacy than the syringe irrigation group (p<0.05). According to the study's results, the agitation of chlorohexidine gluconate fluid by Erbium laser in photon-induced photoacoustic streaming at 0.75 W offers better Enterococcus faecalis biofilm removal in the difficult-to-reach areas of lower first and second molars. Key words:Atomic force microscope, 2% chlorhexidine gluconate, Enterococcus faecalis, Erbium, chromium-doped yttrium, scandium, gallium, garnet laser, passive ultrasonic.

Investigating the effect of Er,Cr:YSGG laser agitation of sodium hypochlorite on the removal of mature biofilm in the complex root canal systems using atomic force microscopy.

Endodontic infections caused by remaining biofilm following disinfection with chemical fluids encourage secondary bacterial infection; hence, employing laser pulses to activate the fluids is advised to improve microbial biofilm clearance. This study investigated the performance of Er,Cr:YSGG laser in photon-induced photoacoustic streaming (PIPS) agitation of 5.25% sodium hypochlorite (NaOCl) to enhance the removal of mature Enterococcus faecalis (E. faecalis) biofilms in complex root canal systems. The mesial roots of the lower first and second molars were separated and inoculated with E. faecalis bacteria for 30 days. The roots were irrigated with 5.25% NaOCl, some of them were agitated with passive ultrasonic irrigation (PUI), and the other roots were agitated by Er,Cr:YSGG laser using PIPS at 60 µs/pulse, 5 Hz, and 0.25, 0.5, 0.75, 1, and 1.25 W. An atomic force microscope (AFM) was used as a new method to obtain the results in the isthmus area; the results that have been obtained from each group were compared with each other. ANOVA was utilized to compare the means of the test groups. Based on the AFM and SEM analyses, laser agitation and passive ultrasonic activation groups have shown higher antimicrobial efficacy than the conventional syringe irrigation group (P<0.05). Based on the findings of this investigation, the agitation of 5.25% NaOCl solution by Er,Cr:YSGG laser in PIPS at (60 µs/pulse, 5 Hz, 1.25 W) offers better mature bacterial biofilm removal in the mesial root of lower human molars than the same irrigant with syringe irrigation and passive ultrasonic activation technique.

Effectiveness of different supplementary protocols for remaining filling material removal in endodontic reintervention: an integrative review.

The aim of this study was to perform an integrative review to identify the most effective supplementary protocols used after filling material (FM) removal and root canal reinstrumentation, during endodontic reintervention. The literature search was performed on the electronic databases PubMed and Latin American and Caribbean Health Sciences Literature (LILACS), using a combination of specific scientific descriptors. Selection criteria accepted articles published in English, Spanish and Portuguese languages, up to August 2021, involving in vitro and ex vivo studies. After applying the eligibility criteria, 46 articles were included for qualitative analysis. The tool for qualitative analysis of quasi-experimental studies of the Joanna Briggs Institute was used to determine the risk of bias of the included articles. The selected articles provided important data regarding the following supplementary protocols: sonic and ultrasonic activation of the irrigating solution; the use of ultrasonic inserts, XP-endo system instruments, and photon-induced photoacoustic streaming for mechanical debridement; and new devices as GentleWave system, and the self-adjusting file. Overall, all supplementary protocols demonstrated efficacy in removing the remaining FM. The implementation of various supplementary protocols can effectively remove the remaining FM from the root canal walls, although complete removal is not always achieved. However, it was not possible to determine the most effective protocol. Conversely, their association can enhance remaining FM removal. Remaining FM attached to root canal walls hinders proper chemical-mechanical preparation during endodontic reintervention. Supplementary protocols optimize the remaining FM removal, enhancing cleaning and disinfection of root canal.

Pretreatment of Root Dentin Using Photon-Induced Photoacoustic Streaming, Photodynamic Therapy, and Riboflavin with EDTA as a Final Irrigant to Improve Bond Integrity of Glass Fiber Post.

Objective: To evaluate the outcome of post space disinfection using Er,Cr:YSGG laser (ECYL), riboflavin photosensitizer (RFP), and photon-induced photoacoustic streaming (PIPS) along with ethylene diamine tetra acetic acid (EDTA) as final irrigant on the bond values of glass fiber post (GFP) to the canal wall. Materials and methods: Forty human mandibular premolars were subjected to root canal treatment after decoronation till the cementoenamel junction. Post space was prepared using a Gates-Glidden drill leaving 4 mm of gutta perch at the apical third of the root section. Random allocation of samples was performed into four groups based on the post space disinfection (n = 10 each): Group 1: 1% RFP and 17% EDTA, group 2: 5.25% sodium hypochlorite (NaOCl) and 17% EDTA (control), group 3: PIPS and 17% EDTA, and group 4: ECYL and 17% EDTA. GFP was luted using Rely X Unicem. A universal testing machine and stereomicroscope were used to assess the push-out bond strength (PBS) and failure mode, respectively. Analysis of variance determined the PBS amid different experimental groups at three root levels. Multiple group comparison using means of tested groups was identified using post hoc Tukey. Results: The coronal third of group 2 (5.25% NaOCl +17% EDTA) demonstrated the highest PBS (8.83 ± 0.11 MPa). However, the lowest bond integrity (4.15 ± 0.52 MPa) was displayed in an apical third of group 1 (RFP +17% EDTA). The intergroup comparison revealed that 5.25% NaOCl +17% EDTA at all three levels demonstrated comparable outcomes of PBS with PIPS +17% EDTA and ECYL +17% EDTA specimens (p > 0.05). However, riboflavin +17% EDTA demonstrated the lowest bond strength (p < 0.05). Conclusions: Er,Cr: YSGG and PIPS in combination with 17% EDTA demonstrated comparable outcomes of bond score with those of conventional gold standard irrigation regime 5.25% NaOCl.

Comparable Effectiveness of Photon-Induced Photoacoustic Streaming with XP-Endo Finisher and Passive Ultrasonic Irrigation on Removing Residual Root Canal Filling Materials from Oval Canals.

Objective: This study aimed to evaluate the effectiveness of photon-induced photoacoustic streaming (PIPS), XP-endo Finisher (XPF), and passive ultrasonic irrigation (PUI) for the removal of root canal filling materials from oval root canals. Background: Various adjunctive irrigation techniques following mechanical preparation have been applied to enhance removal of fillings during root canal retreatment. However, whether there is superiority of one approach over others remains controversial. Methods: Thirty extracted single-rooted teeth with oval-shaped canals were instrumented with the ProTaper Next (PTN) system and obturated with the warm vertical compaction technique. After storage at 37°C for 1 month, retreatment was performed with the PTN system up to size X4. The teeth were then randomly assigned into three groups (n = 10) that were, respectively, subjected to supplementary irrigation with different protocols: PIPS, PUI, and XPF, followed by measurement of filling material volumes using high-resolution micro-computed tomography. Results: The PTN preparation resulted in significant reductions in residual filling materials (p < 0.05), whereas PIPS, PUI, and XPF moderately improved the removal of the remnants (p > 0.05). The residual filling materials after supplementary irrigation ranged from 0.384 ± 0.181 to 0.421 ± 0.143 mm3 in oval canals. There was no significant difference in the effectiveness among the PIPS, PUI, and XPF approaches (p > 0.05). Conclusions: Mechanical preparations are useful for removing most root fillings during retreatment in oval-shaped canals. PIPS can reduce residual root-filling materials to the similar extent as PUI and XPF.

Photo-induced photoacoustic streaming and pineapple peel extract as final irrigant on extrusion bond strength of root filling material to canal wall.

Photon-induced photoacoustic streaming (PIPS) with pineapple peel extract (PPE) and ethylenediaminetetraacetic acid (EDTA) as a final endodontic irrigant on the push-out bond strength (PBS) of root filling material to conventional irrigation NaOCl with EDTA. An in vitro study at Dar Al Uloom University was conducted over three months. Root canal preparation was performed. Based on final irrigation, all the specimens were divided randomly into four groups (n=10) Group 1: 2.25% NaOCl+ 17% EDTA (control), Group-2: 2.25% NaOCl+PIPS + 6.25% PPE, Group-3: 2.25% NaOCl+PIPS + 17% EDTA, Group-4: 2.25% NaOCl + 6.25% PPE. Canals were obturated and sealed with AH Plus sealer. Root sectioning was performed at 1mm thickness and PBS testing was performed using the universal testing machine. The debonded samples were analyzed for failure mode. ANOVA compared the means and standard deviations (SD) of all investigated group. Assessment of multiple comparisons was performed using Tukey's post hoc test. The maximum PBS was demonstrated by the coronal section of Group-2 (2.25%NaOCl +PIPS+6.25%PPE) specimens (8.21±0.81MPa). The apical section of Group-1 (2.25% NaOCl+17% EDTA) specimens demonstrated minimum bond strength (2.80±0.18 MPa). The intergroup comparison revealed that Group-3 (2.25% NaOCl +PIPS +17% EDTA) and Group-2 demonstrated comparable outcomes (p>0.05). Group-4 (2.25% NaOCl +6.25% PPE) specimens established significantly lower values than Group-3 and Group-4 (p<0.05). Photon-induced photoacoustic streaming with pineapple peel extract and EDTA demonstrated better bond strength of root canal sealer and have the potential to be used as the final irrigant.

The Impact of Different Final Apical Preparation Diameters on the Efficiency of Photon-Induced Photoacoustic Streaming (PIPS) in Removing the Smear Layer at the Apical Third

Aims: Photon-induced Photoacoustic streaming (PIPS) as an adjunct to conventional irrigation (CI) using different final apical preparation diameters on smear layer (SL) Material and method: Clinical crown was removed from forty human mandibular molars standardizing root length to 18 mm. Chamber was opened and straight-line access was established Working length was kept 1 mm short of the apex. Teeth were randomly divided into 4 investigated groups based on the final apical diameter. Group-1 (F1+CI+PIPS), Group-2 (F2+CI+PIPS), Group-3 (F3+CI+PIPS) and Group-4 (F3+CI) (Control). CI protocol (2.5% NaOCl+17% EDTA+2.5% NaOCl+distilled water). SEM magnification of 5000x dentinal tubules’ patency at the apical third of root canals was assessed. ANOVA and Tukey’s HSD test were used for data analysis (p = 0.05) Results: Group-3 (F3+CI+PIPS displayed the highest mean scores (3.64±0.50) of SL removal from the apical third of the canal. However, Group-1 (F1+CI+PIPS) exhibited the lowest mean scores (1.27±0.47). Intergroup comparison analysis revealed that Group 1 and Group 2 (F2+CI+PIPS) presented the lowest and most comparable SL removal (p &gt;0.05) Conclusion: Photon-induced Photoacoustic streaming should be considered as an adjunct therapy to improve the cleanliness of the Smear layer from the apical third.

Effect of Passive Ultrasonic Irrigation, Er,Cr:YSGG Laser, and Photon-Induced Photoacoustic Streaming against Enterococcus faecalis Biofilms in the Apical Third of Root Canals.

This study aimed to compare the antibacterial effectiveness of passive ultrasonic irrigation (PUI), Er,Cr:YSGG laser (WTL), and photon-induced photoacoustic streaming (PIPS) using an Er:YAG laser against Enterococcus faecalis biofilms in the apical third of root canals. Root canals of 70 single-rooted human teeth were instrumented and infected with E. faecalis for 3 weeks to form biofilms. The samples were randomly divided into five groups as follows: (i) PUI + 3% NaOCl (n = 16); (ii) Er,Cr:YSGG laser (n = 16); (iii) PIPS + 3% NaOCl (n = 16); (iv) positive control group (n = 10); and (v) negative control group (n = 10). The bacterial content in the root canal was sampled using (a) the paper-point sampling method before (S1) and after (S2) treatment and (b) pulverising the apical 5 mm of the root. The number of bacteria recovered from each group was counted as colony-forming units (CFUs). The amount of reduction between the groups was compared with the Kruskal-Wallis test and post-test Dunn's multiple comparisons tests. The significance level was set at 5% (p < 0.05). The samples from the paper-point sampling method showed that the amount of bacteria before (S1) and after treatment (S2) was significantly different between PIPS and WTL, as well as between the PUI and WTL groups. In contrast, no significant difference was found between the PIPS and PUI groups. From the pulverised samples, the results indicated no significant difference among all experimental groups in the amount of bacterial reduction in the apical 5 mm of the root. PUI and PIPS showed a significantly greater reduction in bacterial content within the main root canal compared with the WTL. There was no difference among all experimental groups in the apical third of the root.

Antimicrobial effectiveness of different irrigation activation techniques on teeth with artificial internal root resorption and contaminated with Enterococcus faecalis: a confocal laser scanning,icroscopy analysis.

This study aimed to compare the antibacterial efficacy of standard needle irrigation (SNI), EDDY, passive ultrasonic irrigation (PUI), photon-induced photoacoustic streaming (PIPS), and shock wave enhanced emission photoacoustic streaming (SWEEPS) activation on the teeth with simulated internal root resorption (IRR) and contaminated with Enterococcus faecalis (E. faecalis) using confocal laser scanning microscopy (CLSM) analyses. A total of 79 human maxillary central incisors with a single canal were selected. The canals were accessed, and then, the roots were split in the bucco-lingual direction. Artificial IRR cavities (depth of 0.8mm and a diameter of 1.6mm) were prepared using round burs and 20% nitric acid in the middle region of the root halves. The root halves were reconstructed with cyanoacrylate glue, and the canals were contaminated with a culture of E. faecalis for 30days. Root canal preparation was performed using the ProTaper Next rotary files up to X5 and 2.5% NaOCl irrigation. Teeth were randomly assigned to five groups according to the irrigation activation method (n = 15): SNI, EDDY, PUI, PIPS, and SWEEPS. The final irrigation procedures were performed using a total of 6mL of 2.5% NaOCl for each tooth with an activation time of 3 × 30s. The canals were stained with LIVE/DEAD BacLight dye and analyzed with CLSM to determine the percentages of dead bacteria in the biofilm. Two-way ANOVA and post hoc Tukey tests were used for statistical analysis (P < .05). None of the irrigation activation methods tested provided 100% bacterial elimination. There was no significant difference between the irrigation activation methods tested in terms of the percentage of dead bacteria (P > 0.05). In irrigation activation methods other than PIPS, there was no significant difference in the percentage of dead bacteria between the coronal, middle, and apical regions of the roots (P > 0.05). A higher percentage of dead bacteria was found in the middle region compared to the apical region in the PIPS (P < 0.05). Within the limitations of this study, SII, EDDY, PUI, PIPS, and SWEEPS have a similar antimicrobial effect on the teeth with IRR and contaminated with E. faecalis.

Comparative analysis of reduction in pain scores after single visit root canal treatment using endodontic irrigation protocols, namely, Conventional needle irrigation, PUI, PIPS and SWEEPS: A randomized control trial.

To assess the effects of different irrigation activation systems on postoperative pain using a Visual Analog Scale (VAS), using new laser irrigation activation system shock wave-enhanced emission photoacoustic streaming (SWEEPS), photon-induced photoacoustic streaming (PIPS), passive ultrasonic irrigation activation techniques, compared with the conventional irrigation (CI) method. Sixty patients suffering from symptomatic irreversible pulpitis in maxillary or mandibular molars were enrolled and randomly assigned to four different irrigation activation groups (n = 15) after chemomechanical root canal preparation. Preoperative and postoperative pain scores were recorded using VAS. The data were collected and subjected to statistical analysis using IBM SPSS 20.0 software at a level of significance being 0.05. We observed that mean pain scores decreased with time in all patients in all groups. The decrease in pain score was found to be statistically significant (P < 0.05) among both the genders in Group 3 (PIPS) and Group 4 (SWEEPS). Postoperatively, pain scores decreased significantly using Group 4 (SWEEPS), followed by Group 3 (PIPS), Group 2 (ultrasonic activation), and Group 1 (conventional needle irrigation). No significant relation was observed statistically between pain scores and age groups among all groups, except for preoperative score in Group 3 and age groups. Postoperative scores were lower in laser-activated irrigation systems as compared to the other activation systems. The highest pain scores were observed in case of CI method, at pre- and post-operative periods.

The microbial community of persistent endodontic infection and the use of root canal disinfectants against E. faecalis: In vitro and in vivo review

In cases of unsuccessful endodontic treatment, E. faecalis is commonly detected and remains popular among the scientific community for in vitro and in vivo research. The nature of the bacteria's predominance is dependent on the difficulty in cleaning the apical portion of the tooth and E. faecalis' capacity to grow deep into the dentinal tubules. The purpose of this review is to gather current research on root canal disinfection against E. faecalis. In this literature review, four databases were searched: PubMed, EBSCOhost, ScienceDirect, and Google Scholar, with explicit inclusion and exclusion criteria. The compiled review shows that a predominant multi-microbial community within a persistent root canal infection include Porphyromonas gingivalis, Fusobacterium nucleatum, and Enterococcus faecalis. E. faecalis produces moderate biofilms and causes infection through its virulence factors such as esp, cylA, ace, gelE, asa, and efaA. Several disinfecting agents and approaches have been explored for their capacity to eradicate E. faecalis and penetrate the dentinal tubules. Sodium hypochlorite (NaOCl) and chlorhexidine (CHX) gel eliminate E. faecalis and other resistant microbes such as Staphylococcus aureus, and Escherichia coli. Combing NaOCl irrigation with the following: Photon-induced photoacoustic streaming, passive ultrasonic irrigation, and diode laser irradiation, eradicates E. faecalis. The current research has shifted towards nanoparticles against E. faecalis because of its dissolution capacity, size, and antimicrobial efficacy. E. faecalis resists calcium hydroxide through its proton pump mechanism, but it is susceptible to Ca(OH)2 when applying a proton pump inhibitor or chlorhexidine.

The Effect of High-Power Lasers on Root Canal Disinfection: A Systematic Review.

Introduction: In root canal therapy, the cleaning and shaping of canals are routinely applied by clinicians in order to remove microorganisms. Eradicating bacteria from the root canal system plays a crucial role in long-term success; however, it is not always easy to disinfect root canals properly because of their complicated anatomy and bacterial load. Achieving an optimally disinfected root canal environment requires adjunctive antibacterial therapeutic methods. High-power laser utilization as an adjunctive strategy to conventional treatment is a relatively new approach that helps clinicians. Methods: This study was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline. Online databases, namely Web of Science, PubMed/MEDLINE, Scopus, and Cochrane Library, were searched electronically regarding lasers and endodontic treatments. Appropriate studies were included according to the inclusion/exclusion criteria. Results: Among 504 obtained studies by search, 48 were considered for a detailed analysis. Ten articles performed in vivo evaluation, while nine assessed the effect of lasers on artificial models, and 29 conducted ex vivo experiments on extracted teeth. When the diode laser, the most frequently used laser, was utilized as an adjunct therapy after NaOCl irrigation, it killed more bacteria than conventional irrigation with NaOCl. Laser-activated irrigation (LAI) with the Er, Cr: YSGG laser and NaOCl disinfects the root canal effectively. Also, photon-induced photoacoustic streaming (PIPS) with Er: YAG and NaOCl exhibited a high bactericidal effect and deep tubular penetration. Conclusion: High-power laser utilization, considering proper case selection and method, can assist in root canal treatment of infected teeth.

Comparison of vapor bubble kinetics and cleaning efficacy of different root canal irrigation techniques in the apical area beyond the fractured instrument

Background/purposeIntracanal fractured instruments hamper adequate root canal disinfection. The aim of this study was to evaluate vapor bubble kinetics and cleaning efficacy of different irrigation techniques in the apical area beyond the fractured instrument. Materials and methodsSixty curved root canal models, in which a 3-mm fragment of a #20 K-file or a WaveOne Gold Primary (WOG) instrument was intentionally separated at 3 mm from the apical foramen, were irrigated with laser-activated irrigation with photon-induced photoacoustic streaming (LAI-PIPS; 20 mJ/15 Hz), laser-activated irrigation using an Er:YAG laser unit (LAI; 30 mJ/20 Hz), or ultrasonic-activated irrigation (UAI) for 5 s. Vapor bubble velocity and counts were analyzed using high-speed video imaging. To evaluate canal wall cleanliness, 40 canals of extracted human teeth with an intentionally separated 3-mm WOG fragment in the canal at 3 mm from the apical foramen were irrigated with LAI-PIPS, LAI, UAI or conventional syringe irrigation, using 17% EDTA (30 s, two cycles), saline (30 s), and 3% NaOCl (30 s, three cycles) as irrigants. Debris and smear layer on the apical canal wall beyond the fractured instrument were scored using scanning electron microscopy. ResultsLAI-PIPS and LAI demonstrated higher vapor bubble counts than UAI. The WOG fragment permitted higher bubble velocity and count than the K-file fragment. LAI-PIPS and LAI showed better debris and smear removal than the other techniques. ConclusionLAI and LAI-PIPS demonstrated higher vaporized bubble kinetics and better cleaning efficacy in the apical area, even in the presence of a fractured instrument.

The Impact of Laser-Activated and Conventional Irrigation Techniques on Sealer Penetration into Dentinal Tubules.

Objective: The present study was aimed at comparing the efficacy of 1-hydroxyethylidene-1, 1-diphosphonic acid (HEDP) and ethylenediaminetetraacetic acid (EDTA) by using various final irrigation techniques on penetration of sealer. Background: Traditional irrigation of root canals with a syringe limits the ability of sealer penetration. Various irrigants and activation techniques, including sonic and ultrasonic devices and various kinds of lasers, have been introduced to improve penetration of sealers into dentinal tubules. Methods: One hundred mandibular premolars were selected. Final irrigation was performed with HEDP or EDTA by conventional syringe irrigation (CI), EndoActivator (EA), passive ultrasonic irrigation (PUI), photon-induced photoacoustic streaming (PIPS), and shock wave-enhanced emission photoacoustic streaming (SWEEPS) methods (n = 10). After obturation of root canals with the EndoSequence BC Sealer, samples were evaluated using a confocal laser scanning microscope (CLSM), which enabled measurement of the maximum depth, percentage, and penetration area. Tests performed for analysis included the Kruskal-Wallis H and Mann-Whitney U tests. Results: In the EA method, the penetration percentage achieved using HEDP was significantly higher than EDTA at both sections (p < 0.05). Irrespective of the final irrigation solution employed, the PUI, PIPS, and SWEEPS techniques exhibited greater tubule penetration values compared with the CI and EA techniques (p < 0.05). Conclusions: HEDP and EDTA showed similar effects on the amount of penetrated sealer into the dentinal tubules, and the PUI, PIPS and SWEEPS methods provided enhanced EndoSequence BC Sealer penetration compared with the CI and EA methods. This study was approved by the Near East University institutional review board (#2020/86-1225).

Evolution of the combined effect of different irrigation solutions and activation techniques on the removal of smear layer and dentin microhardness in oval-shaped root canal: An in-vitro study.

The aim of this in vitro study was to evaluate the effect of three final irrigants, namely QMix, MTAD and EDTA, combined with three irrigation techniques, namely conventional needle irrigation (CNI), passive ultrasonic irrigation (PUI) and photon-induced photoacoustic streaming (PIPS), on smear layer removal, dentin mineral content and microhardness in oval-shaped canals. 130 decoronated premolars with single, oval root canals were equally divided into1 blank control group and 12 treatment groups (n=10) according to the final irrigation protocols. Roots in treatment groups were instrumented with ProTaper Gold to size F4 and subjected to final irrigation. Smear layer removal was assessed by using a four-level scoring system under an environmental scanning electron microscope. Energy dispersive X-ray spectroscopy was performed to measure the dentin mineral content. Dentin microhardness was measured by Knoop microhardness testing. Statistical analysis of the data was performed by using Kruskal-Wallis test, followed by Dunn's post hoc test with Bonferroni correction. PUI- and PIPS-activated QMix and EDTA removed smear layer more effectively than MTAD groups (p<0.05). Regarding the dentin mineral content and microhardness, QMix groups yielded the least calcium (Ca), phosphorus (P) and Ca/P ratio, followed by EDTA groups and MTAD groups (p<0.05). QMix groups produced significantly lower dentin microhardness values and higher hardness reduction percentages than MTAD groups (p<0.05). Within the limitations of the present study, it was concluded that QMix and EDTA were superior to MTAD in smear layer removal, especially when activated by PUI and PIPS, but these agents produced more pronounced effect on dentin mineral content and microhardness than MTAD.