Photon-initiated Photoacoustic Streaming Research Articles

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.

Comparison of the Photon-initiated Photoacoustic Streaming Technique and a Combination of Different Irrigation Activation Regimens on the Removal of Modified Triple Antibiotic Paste

Amaç: Bu çalışmanın amacı, kök kanallarından modifiye üçlü antibiyotik patının (mTAP) çıkarılmasında foton kaynaklı fotoakustik dalgalanma (PIPS) tekniği ile farklı irrigasyon aktivasyon rejimlerinin kombinasyonunun etkinliğini karşılaştırmaktır.&#x0D; Gereç ve Yöntemler: Yüz beş adet çekilmiş insan mandibular-premolar dişler ProTaper döner eğe kullanarak prepare edildi. Kök kanalları mTAP medikamenti ile dolduruldu ve 4 hafta sonra kökler kullanılan irrigasyon rejimlerine göre rastgele 7 gruba (n=15) ayrıldı: Self-Adjusting File (SAF), Pasif-Ultrasonik-İrrigasyon (PUI) , EndoAktivatör (EA), SAF+EA, SAF+PUI, PUI+EA, PIPS. 3 dişte mTAP kaldırılmadı (pozitif kontrol) ve diğer 3 diş mTAP ile doldurulmadı (negatif kontrol). Kökler uzunlamasına ikiye ayrıldı ve kalan mTAP miktarı, 4 dereceli bir skorlama sistemi kullanılarak 20x büyütme ile değerlendirildi. Veriler Kruskal-Wallis ve Mann-Whitney U testleri kullanılarak değerlendirildi.&#x0D; Bulgular: Tüm deney grupları arasında istatistiksel olarak anlamlı farklılık tespit edildi. PIPS, SAF, SAF+EA ve SAF+PUI, mTAP'yi kök kanalından çıkarmada PUI ve PUI+EA'dan önemli ölçüde daha iyi performans gösterdi (P=0.000). EA orta etkinlik gösterdi. Apikal ve orta üçte birlik kısımda PUI ve PUI+EA ve koronal üçte birlik kısımda PUI önemli ölçüde daha kötü performans gösterdi (P

Efficacy of passive ultrasonic activation and photon-initiated photoacoustic streaming on apical extruded debris of different rotary systems in curved canals

Aim: The aim of this study was to investigate the impact of photon-initiated photoacoustic streaming (PIPS) and ultrasonic activator Ultra X (UX) on the extrusion of debris using the One Curve (OC) rotary system and the Reciproc Blue (RB) system in curved canals. Methodology: Ninety extracted mandibular first molar teeth were divided into six groups (n = 15), Group (1): OC with PIPS, (2) OC with UX, (3) OC with conventional needle irrigation (CNI), (4) RB with PIPS, (5) RB with UX, and (6) RB with CNI. The irrigation activation methods were used in the final irrigation with 2.5 cc of distilled water. The apically protruded debris was collected into pre-weighed Eppendorf tubes. By deducting the tube's initial weight from the final weight, the weight of dry protruded debris was calculated. Two-way ANOVA test was used to analyze the results statistically. Results: A significant difference was found among all groups (p &lt; 0.05). No statistically significant difference was found among the instrumentation systems, regardless of the irrigation technique employed (p &gt; 0.05). The statistically significant difference was found among the PIPS, UX, and CNI irrigation systems, regardless of the rotary systems (p &lt; 0.05). CNI caused significantly less debris extrusion than the UX ultrasonic irrigation activation systems. Conclusion: The UX irrigation activation system caused the highest amount of debris extrusion in curved canals. PIPS can be preferred to ultrasonic devices as irrigation activation systems. How to cite this article: Akman M, Bozkurt DA, Zogheib C. Efficacy of passive ultrasonic activation and photon-initiated photoacoustic streaming on apical extruded debris of different rotary systems in curved canals. Int Dent Res 2023;13(1):13-18. https://doi.org/10.5577/idr.2023.vol13.no1.3 Linguistic Revision: The English in this manuscript has been checked by at least two professional editors, both native speakers of English.

Influence of irrigation and laser assisted root canal disinfection protocols on dislocation resistance of a bioceramic sealer

BackgroundIt is not yet clear how different irrigation protocols and intracanal laser irradiation effects bioceramic sealers. In this vitro study, we aimed to evaluate the dislocation resistance of a bioceramic root canal sealer after different laser-assisted disinfection protocols and irrigants. MethodsSixty extracted human straight single-canal teeth were instrumented, and randomly divided into five experimental groups (n=10) according to the disinfection protocol used: group 1, conventional needle irrigation (CI) with sodium hypochlorite (NaOCl)+ethylenediaminotetraacetic acid (EDTA)+NaOCl; group 2, Photon initiated photoacoustic streaming (PIPS) of NaOCl+EDTA+NaOCl; group 3, NaOCl+EDTA+diode laser; group 4, NaOCl+EDTA+photodynamic therapy (PDT); group 5, CI with NaOCl+EDTA+Chlorhexidine (CHX); and control group without any treatment. The root canals were filled with a bioceramic root canal sealer (BioRoot RCS) using the single-cone filling technique. After three weeks of storage, the samples from each canal thirds were transversely sectioned and the push-out test was performed. ResultsThe PIPS group showed the lowest dislocation resistance values in the coronal third (p>0.05), and no difference was observed among the other groups (p<0.05). The dislocation resistance in the middle and apical thirds was the highest in the diode laser group (p<0.05). ConclusionFinal root canal irradiation with diode laser led to improved dislocation resistance of the bioceramic sealer. PDT did not adversely affect the dislocation resistance of BioRoot RCS. The PIPS reduced the dislocation resistance values in the coronal third, but not in the middle and apical thirds.

Evaluation of dentinal tubule penetration of Irritrol and chlorhexidine irrigating solutions activated using EDDY and photon-initiated photoacoustic streaming

The aim of the study was to compare the penetration depth and percentage of Irritrol and chlorhexidine (CHX) solutions into dentinal tubules using conventional needle irrigation (CI), EDDY, and photon-induced photoacoustic streaming (PIPS). Sixty oval shaped mandibular premolar teeth were divided into two main groups according to the irrigating solutions as follows; Irritrol and CHX, which were later randomly divided into three subgroups according to the activation technique; CI, EDDY and PIPS (n = 10). Following the irrigation activation procedures, all roots were horizontally sectioned at 3 (apical), 8 (middle), and 13 (coronal) mm from the root apex and then examined with confocal laser scanning microscope (CLSM). Penetration depth (µm) and penetration percentage (%) as determined from the images were analyzed using LSM Image Browser software (Zeiss) and Image J analysis software (V. 1.44p; National Institutes of Health, Bethesda, MD), respectively. Data were statistically analyzed using Kruskal–Wallis and Mann–Whitney U tests were performed for multiple comparisons. In both Irritrol and CHX groups, the PIPS activation system demonstrated the highest values for irrigant penetration depth and penetration percentage compared with the other activation methods. Activation of the CHX and Irritrol the final irrigating solutions with PIPS activation technique improved the penetration depth and percentage solutions into the dentinal tubules.

Evaluation of Dentinal Tubule Penetration of Irritrol and Chlorhexidine Irrigating Solutions Activated Using Eddy and Photon-Initiated Photoacoustic Streaming

Evaluation of Dentinal Tubule Penetration of Irritrol and Chlorhexidine Irrigating Solutions Activated Using Eddy and Photon-Initiated Photoacoustic Streaming

ENTEROCOCCUS FAECALIS BİYOFİLM ELİMİNASYONUNUN ER:YAG MODALİTELERİNE (PIPS VE SWEEPS) GÖRE KARŞILAŞTIRILMASI

Background and purpose: To determine the effectiveness of novel two Er:YAG lasers, photon-initiated photoacoustic streaming (PIPS\SSP) and shock wave-enhanced emission photoacoustic streaming (SWEEPS\AutoSWEEPS) in terms of removal Enterococcus faecalis (E. faecalis) with or without antimicrobial agents (NaOCl and chlorhexidine gluconate). &#x0D; Methods: Forty-two extracted single-rooted mandibular premolars were prepared, sterilized, and then inoculated with E. faecalis for 4 weeks, and randomly divided into to two main and three subgroups (n= 7). Group Ia ( PIPS + distilled water), Group Ib (PIPS + 5% NaOCl), Group Ic (PIPS + CHX), and Group IIa (SWEEPS + distilled water), Group IIb (SWEEPS + 5% NaOCl), and Group IIc (SWEEPS + CHX). Following incubation for 48 hours at 37°C, the colonies formed (CFU) were counted. &#x0D; Results: NaOCl and CHX activated with PIPS\SSP or SWEEPS\AutoSWEEPS modalities showed significantly higher reduction rates than distilled water activated with both laser-activated methods (p0.05). &#x0D; Interpretation: Even novel laser activation methods or modalities are not sufficient alone to adequately reduce bacterial load and using antimicrobial agents with laser activation is necessary for the best reduction for microbial elimination. Novel SWEEPS\AutoSWEEPS modalıty with the conical 600μm tip showed no increased efficacy compared with PIPS\SSP mode. Besides, smaller fiber tip may increase the success of applications for minimally invasive access cavities and preparation.

The antibacterial efficacy of photon-initiated photoacoustic streaming in root canals with different diameters or tapers

BackgroundIn recent years, the concept of minimally invasive endodontics has been proposed, which could be described as preventing or treating diseases by preserving more dental tissue and creating minimal damage. In the process of root canal preparation, it was recommended to use instruments with a smaller taper to preserve more tooth tissue and improve the preservation rate of the affected teeth. Photon-induced photoacoustic streaming (PIPS) was a new type of laser-activated irrigation technology, which was now widely used in endodontic treatment. The purpose of this article was to evaluate the bactericidal effect of PIPS with NaOCl in root canals with different widths or tapers.MethodsTwenty-three maxillary first molars with three independent root canals were included in this study. The mesiobuccal (MB), distobuccal (DB), and palatal (P) root canals were prepared at sizes of #10/.02, #25/.02, and #25/.06, respectively. After being incubated with a bacterial suspension for 4 weeks, the specimen were irrigated with 2% NaOCl activated by conventional needle irrigation (CNI) (n = 10) or PIPS (n = 10). Three specimen were not treated (control group). Before and after irrigation, the presence of bacteria was assessed with an adenosine 5'-triphosphate (ATP) assay kit and biofilms were assessed using confocal laser scanning microscopy and scanning electron microscopy.ResultsIn specimen prepared using PIPS irrigation, the ATP was reduced by more than 98%. When the root canal taper was 0.02, the size #25 root canals had a higher percentage of dead bacteria than the size #10 root canals in all regions (P < 0.05) in the PIPS group. When the root canal width was #25, the 0.02 taper group had a higher percentage of dead bacteria than the 0.06 taper group in the apical region (P < 0.05), except coronal and middle regions (P > 0.05). PIPS irrigation results in a greater percentage of dead bacteria and reduction of ATP in size #10/.02 root canals than CNI in size #25/.06 root canals in three regions (P < 0.05).ConclusionIncreasing the width from #10 to #25 improves the bactericidal effect of PIPS in the root canal. Increasing the taper of the root canal from 0.02 to 0.06 at size #25 did not affect the bactericidal effects of PIPS. PIPS resulted in more dead bacteria in specimen with smaller tapers and root canal widths than CNI. PIPS can be used to clean the smear layer in the coronal region and open the dentin tubules.Clinical significance: Activation of irrigants with PIPS brought about significant bacterial reduction smaller tapers and width root canals compared to CNI, which was beneficial to prevent excessive loss of tooth tissue and conserve the structural integrity of teeth.

Effectiveness of photon-initiated photoacoustic streaming in root canal models with different diameters or tapers

BackgroundThis study aimed to compare the use of photon-initiated photoacoustic streaming (PIPS) and conventional needle irrigation (CNI) in conjunction with different concentrations of sodium hypochlorite (NaOCl) to remove Enterococcus faecalis (E. faecalis) suspended bacteria and biofilms from root canal systems with different diameters or tapers.MethodsArtificial root canal samples (n = 480) were randomly divided into three groups (n = 160/group). The canals were prepared to fit file sizes #10/.02, #25/.02, or #25/.06. The size #10/.02 group was incubated for seven days. The size #25/.02 or #25/.06 group was incubated for 2 days. A stable biological model of E. faecalis infection was established. The root canals were washed with distilled water or with 1%, 2%, or 5.25% NaOCl combined with CNI or PIPS. Bacterial suspensions and biofilms were assessed using an ATP assay kit and fluorescence microscopy. Image-Pro Plus was used to analyse the average fluorescence intensity to determine the most suitable root canal irrigation solution.ResultsIn the CNI and PIPS groups, the ATP value of the 5.25% NaOCl subgroup was the lowest, followed by that of the 2% and 1% NaOCl subgroups. The ATP value of the distilled water subgroup was the highest (P < 0.05). When the root canal taper was 0.02, the ATP value of the #10/.02 + PIPS group was significantly lower than that of the #25/.02 + CNI group (P < 0.05). The average fluorescence intensity of the #10/.02 + PIPS group was lower than that of the #25/.02 + CNI group (P < 0.05). When the apical diameter was #25, the ATP value of the 0.02 taper in the PIPS group was lower than that of the 0.06 taper in the CNI group (P < 0.05), and the average fluorescence intensity of the 0.02 taper + PIPS group was lower than that of the 0.06 taper + CNI group (P < 0.05). PIPS combined with 2% and 5.25% NaOCl effectively improved the long-term antibacterial effect after irrigation and re-culture for 6 h.ConclusionsCompared with CNI, PIPS has greater ability to remove bacteria in root canals with a small preparation diameter and a small taper. PIPS with 2% and 5.25% NaOCl exhibited superior antibacterial and bacteriostatic effects.

Comparison of the efficacy of laser-activated and ultrasonic-activated techniques for the removal of tricalcium silicate-based sealers and gutta-percha in root canal retreatment: a microtomography and scanning electron microscopy study

BackgroundTricalcium silicate-based sealers have been usually indicated for the single-cone technique and result in more residual filling materials in root canal retreatment. Passive ultrasonic irrigation and photon-initiated photoacoustic streaming have been reported to improve the removal efficacy of root canal filling materials. However, the abilities of both techniques combined with NiTi re-instrumentation to remove residual tricalcium silicate-based sealer and gutta-percha have not been compared. The aim of this study was to evaluate the efficacy of laser-activated and ultrasonic-activated techniques in vitro for the removal of the tricalcium silicate-based sealer iRoot SP and gutta-percha after standard canal retreatment procedures with the use of nickel-titanium (NiTi) rotary instruments.

Comparison of Walking-Bleaching and Photon-Initiated Photoacoustic Streaming Techniques in Tooth Color Change of Artificially Colored Teeth.

Background and objective: The aim of this study is to compare the bleaching effect of photon-induced photoacoustic streaming (PIPS) using carbamide peroxide or sodium perborate-20% hydrogen peroxide (H2O2) compared with walking-bleaching techniques using sodium perborate-20% H2O2 or carbamide peroxide without PIPS on artificially colored teeth. Materials and methods: Root canal treatments of 85 extracted human maxillary central incisors were completed and artificially stained using sheep's blood. Teeth were randomly grouped into five groups according to the bleaching techniques to be tested: Group 1: walking bleaching with carbamide peroxide; Group 2: walking bleaching with sodium perborate-20% H2O2; Group 3: PIPS+carbamide peroxide; Group 4: PIPS+sodium perborate-20% H2O2; and Group 5: control. Experimental specimens were bleached for 3 weeks. Buccal surfaces of the crowns were used for spectrophotometric measurements, limited with a 7-mm external diameter rounded strip, before bleaching and on days 7, 14, and 21. The total change in color (ΔE*) were analyzed with Welch's ANOVA at a significance level of p = 0.05 and Tamhane post-hoc test was used for multiple comparisons. Results: Starting from the second week, Group 4 showed significantly better bleaching effect compared with the other groups (p < 0.05). The other experimental groups also have bleaching effects, but there was no statistically significant difference between Group 1, Group 2, and Group 3 (p > 0.05). Conclusions: Sodium perborate-20% H2O2 activated with PIPS gave a bleaching effect superior to that of walking-bleaching techniques or PIPS using with carbamide peroxide.

Smear layer removal and sealer penetration with different tapers after using photon-initiated photoacoustic streaming technique

To evaluate the effect of the photon-initiated photoacoustic streaming (PIPS) technique on irrigation performance with different instrumentation tapers in root canals regarding smear layer removal and subsequent sealer penetration. One hundred twenty human mandibular molars were divided into three equal groups according to the apical preparation taper (25/4%, 25/6%, and 25/8%). Each group was divided into two equal subgroups, one received passive irrigation (PI) while the other received PIPS activation of 2.5% sodium hypochlorite and 17% EDTA. Half the samples were evaluated using electron microscope images to assess smear layer removal. The other half was obturated using gutta-percha and rhodamine B-labeled AH Plus sealer before being sectioned horizontally at different root levels (coronal, middle, and apical) to evaluate the percentage of sealer penetration using CLSM. Mann-Whitney U and Friedman tests were used to analyze smear layer scores, while sealer penetration data were analyzed using the three-way analysis of variance (ANOVA) and Tukey's post hoc test. Statistical analysis showed significantly better smear layer removal and better sealer penetration after PIPS activation when corresponding root thirds were compared (P<0.001). Only exception was sealer penetration in the apical third with root canal preparation of 25/4% where the difference between the irrigation methods was statistically insignificant (P>0.05). The use of PIPS activation in the final irrigation protocol enhanced smear layer removal and sealer penetration into dentinal tubules if the taper of the prepared canal was at least 6%. Increasing apical preparation taper significantly enhances PIPS performance in terms of irrigation activation thus enhancing smear layer removal and subsequent sealer penetration in dentinal tubules.

Efficacy of Laser Photoacoustic Streaming in Paediatric Root Canal Disinfection - An Ex-Vivo Study.

Background:Various techniques have been employed to enhance the root canal disinfection rate using sodium hypochlorite (NaOCl) as an irrigant. Photon initiated photo-acoustic streaming using lasers is a newer method of endodontic disinfection.Aim:The aim of this study is to evaluate and compare the efficacy of photo-initiated photoacoustic streaming and conventional irrigation technique using 2.5% NaOCl for root canal disinfection in primary teeth.Setting and Design:Laboratory setting and ex-vivo design.Materials and Methods:Twenty extracted primary teeth were selected in which Enterococcus faecalis incubation was done in the root canals and bacterial counts were obtained before the intervention. The teeth were randomly allocated into two groups. Group I samples were irrigated with conventional syringe method using 2.5% NaOCl and Group II samples were irrigated using photon-initiated photo-acoustic streaming method with erbium-doped yttrium aluminum garnet laser (wavelength - 2940 nm). Postintervention samples were obtained, and bacterial colony count was done. Wilcoxon Signed- Ranks Test and Mann–Whitney test were applied to test the intragroup and intergroup differences in the bacterial counts. Results:Postintervention results showed no bacterial growth in the canals irrigated using Laser (P = 0.004) whereas, fewer bacterial colonies were observed in NaOCl group (P = 0.005). There was statistically significantly higher reduction in E. faecalis counts in Laser Activated irrigation (LAI) group compared to NaOCl group (P < 0.05).Conclusion:Total elimination of E. faecalis counts was obtained by the use of laser activated NaOCl irrigation in the infected root canals, hence, it can be considered as an effective method for pediatric endodontic disinfection.

Comparison of apical debris extrusion using EDDY, passive ultrasonic activation and photon-initiated photoacoustic streaming irrigation activation devices.

The study aimed to determine the effect of different irrigation activation systems on the amount of apical debris extrusion in mandibular molar teeth with curved root canals. Sixty extracted mandibular molar teeth were instrumented with HyFlex EDM system and divided into four groups according to irrigation techniques: passive ultrasonic irrigation (PUI), EDDY, photon-initiated photoacoustic streaming (PIPS) and manual irrigation (MI). After the final irrigation, the extruded irrigants were collected into Eppendorf tubes of known weights. The amount of extruded debris was obtained by subtracting the weight from the initial weight of the tube. The Kruskal-Wallis test was used for statistical analysis. EDDY caused significantly more debris extrusion than the other irrigation activation systems (P<0.001). PUI caused less apical debris extrusion but there was no statistical difference between PUI, PIPS and MI (P>0.05). The EDDY activation system was associated with the highest amount of debris extrusion in curved root canals.

Retreatability of Bioceramic Endodontic Sealers: a Review.

In 2009 a new type of endodontic sealers was introduced to the market. The so called "bioceramic" sealers are a promising alternative to the present golden standard of root canal fillings. Now a decade later, still very little is known about the ability to remove these sealers in cases of non-surgical endodontic retreatment (NSER). There are only a limited number of articles that provide such information. The commonly used hand files are not efficient in removing thoroughly the sealer from the main canal walls. Machine driven files are much easier and faster alternative to the hand ones, but are still not able to ensure complete removal. Although ultrasonics can be applied only in the straight portion of the main canal, they raise the efficacy of sealer removal. Photon-initiated photoacoustic streaming (PIPS) is another way to enhance the removal of bioceramics. Solvents like chloroform and orange oil are effective in softening gutta-percha, but not the bioceramics. This article reviews the available scientific data concerning removal of bioceramic materials in the context of a NSER.

Efficacy of the photon-initiated photoacoustic streaming combined with different solutions on Enterococcus faecalis in the root canals.

This study aimed to evaluate the efficacy of different irrigation solutions used in photon-initiated photoacoustic streaming (PIPS) or conventional needle irrigation (CNI) for eradication of Enterococcus faecalis from artificial root canals. Altogether, 240 artificial root canal samples were included. The models were split and incubated for 2 days to allow formation of E. faecalis biofilm. The models were randomly divided into two groups (n = 120): CNI and laser-activated irrigation (LAI). Each group was divided into six subgroups according to different irrigation solutions: distilled water, 1% sodium hypochlorite (NaOCl), 2% NaOCl, 5.25% NaOCl, MTAD, and chlorhexidine, respectively. After irrigation, half of the samples (n = 10) were assessed immediately, and the other half of the samples (n = 10) were incubated for 6 hr. Bacterial suspensions were obtained from all samples before and after irrigation, and after incubation, and were quantified adenosine 5'-triphosphate (ATP) assay kit. The biofilms were examined using fluorescent microscopy and analyzed by Image Pro Plus software. Significant reduction of ATP, average fluorescence density after irrigation, and growth after incubation was obtained in LAI group than in CNI group (p < .05). LAI can improve bacteriostasis effect of 2% NaOCl (p < .05). PIPS improved the antibacterial effect of the 2% NaOCl used in root canal therapy.

Comparison of different final irrigant agitation techniques for the removal of Enterococcus faecalis biofilms from root canals: an in vitro study

Objective: The aim of this in vitro study was to compare the effectiveness of different final irrigant agitation techniques in the removal of Enterococcus faecalis biofilms from root canals. Material and Methods: In total, the root canals of 85 extracted single-rooted human maxillary incisors teeth were prepared using the Revo-S system to a 40/06 size. The apical foramen of each tooth was sealed by light-cured resin composite material to obstruct bacterial leakage. The specimens were sterilized in an autoclave at 121°C for 15 min and stored until further use. All teeth except five (negative control group) were inoculated with Enterococcus faecalis and incubated in a CO2 chamber at 37°C for 7 days; the trypticase soy broth was changed every 2 days. For the determination of possible biofilm formation, five of the 80 teeth were randomly selected as a positive control group; one tooth of positive control group was analysed for biofilm development by scanning electron microscope (SEM) and these teeth received no final irrigant agitation procedure. Then, the remaining 75 teeth were randomly divided into five test groups (n=15 each) and were sequentially irrigated with 5% sodium hypochlorite (NaOCl), 17% ethylenediaminetetraacetic acid and 5% NaOCl. Following each irrigant application, different final irrigant agitation techniques were introduced for 60 s (3×20-s sessions). Group 1 received manual–dynamic agitation, group 2 received passive ultrasonic agitation (PUI), group 3 received EndoActivator agitation, group 4 received photon-initiated photoacoustic streaming (PIPS) with the Er:YAG laser and group 5 received conventional syringe irrigation. Colony-forming units (CFUs) were counted in samples from the positive control and test groups. Data were analysed using Kruskal–Wallis and post-hoc Mann–Whitney U multiple comparison tests. Results: E. faecalis elimination was significantly better in the experimental groups than in the positive control groups (p &lt; 0.001). Manual–dynamic agitation and conventional syringe irrigation, with no significant differences between the two groups. Conclusion: Essentially, CFU reduction was significantly greater in the PUI, EndoActivator and PIPS groups than in the manual–dynamic agitation and conventional syringe irrigation groups (p &lt;0.001), with no significant differences among the former three groups.KeywordsEnterococcus faecalis; Irrigant agitation; Irrigant solutions; Photon-initiated photoacoustic streaming; Passive ultrasonic irrigation.

Effect of Combined Use of Photon-Initiated Photoacoustic Streaming and Chitosan on Smear Layer Removal

Effect of Combined Use of Photon-Initiated Photoacoustic Streaming and Chitosan on Smear Layer Removal

The efficacy of photon-initiated photoacoustic streaming in the removal of calcium silicate-based filling remnants from the root canal after rotary retreatment.

The aim of the study was to evaluate the efficacy of photon-initiated photoacoustic streaming (PIPS) in the removal of filling remnants from root canals after rotary phase of retreatment and to examine the difference in the amount of residual material considering the type of sealer. Thirty-six extracted single-rooted human teeth were instrumented and randomly divided into three groups according to the filling material used: group 1: EndoSequence BC Sealer (Brassler, USA), group 2: MTA Fillapex (Angelus Solucoes Odontologicas, Londrina, Brasil), and group 3: AH Plus sealer (Dentsply DeTrey, Konstanz, Germany). Cold lateral condensation technique was used. After 2weeks, the root canals were retreated with a rotary phase retreatment system (ProTaper Universal Retreatment, Maillefer, Ballaigues, Switzerland), followed by Er:YAG laser-activated irrigation (photon-initiated photoacoustic streaming, PIPS). The specimens were scanned in a micro-computed tomographic (micro-CT) device after root canal filling, after the rotary retreatment, and after the PIPS. There was significant reduction in the amount of filling material after the rotary phase of retreatment in all groups (p<0.05), the highest in the MTA Fillapex group (p<0.001) and no difference between the EndoSequence BC and the AH Plus (p=0.608). There was significant reduction of the filling remnants after the PIPS in all groups (p<0.05). The MTA Fillapex was the most easily removed during rotary phase of the retreatment, and there were no differences in the amount of the remaining filling material between EndoSequence BC and the AH Plus groups after rotary phase of the retreatment. The PIPS improved the removal of filling remnants in all groups.

Efficacy of photon-initiated photoacoustic streaming on apically extruded debris with different preparation systems in curved canals.

To determine the effect of photon-initiated photoacoustic streaming (PIPS) on the extrusion of debris using multiple-file (ProTaper Next-PTN) and single-file (One Shape-OS) continuous rotary systems in curved canals in human molar teeth. Sixty extracted maxillary first molar teeth with curved mesial roots, mature apices and of similar lengths were selected. Teeth having canals with apical diameters larger than size 15 were discarded. The teeth were randomly divided into four experimental groups (n=15 teeth per group) according to the file used and irrigation systems: (i) OS with PIPS with a 2940nm Er:YAG laser (0.3W, 15Hz, and 20mJ), (ii) OS with conventional needle irrigation (CNI) with a 27-G needle, (iii) PTN with PIPS and (iv) PTN with CNI. The PIPS and CNI was applied during each file change for 20s. Total irrigation and activation time was 1min, and a total volume of 7.5mL of bidistilled water was used as the irrigant. The apically extruded debris was collected into pre-weighed Eppendorf tubes. The tubes were then stored in an incubator at 70°C for 5days. The weight of dry extruded debris was assessed by subtracting the initial weight of the tube from the final weight. The results were analysed statistically using one-way analysis of variance and Tukey's post hoc tests. Bonferroni correction was used to compare the groups. The PIPS irrigation technique was associated with significantly more debris extrusion than the CNI system (P<0.05). The single-file (One Shape-OS) rotary system was associated with more debris than the multiple-file (ProTaper Next-PTN) rotary systems when the same irrigation system was used (P>0.05). The total amount of debris extruded apically by PIPS activation was significantly greater than that by CNI (P<0.05). All file and irrigation systems extruded debris apically. PIPS activation was associated with significantly more extrusion debris in curved canals compared with no activation.