Dentinal tubule penetration following ultrasonic, sonic, and single-cone technique of a biosealer: An ex vivo study

Background

The endodontic space is complex, and using a single-cone obturation technique fails to ensure a complete filling.

Introduction

This study aimed to investigate the effect of ultrasonic activation, sonic activation, and single-cone technique of a biosealer on its dentinal tubular penetration.

Materials and Methods

In the experiment, single-root mandibular premolars were randomly assigned to three groups (n = 20): group A, ultrasonic activation; Group B, sonic activation; and Group C, single-cone technique. Penetration of the fluorescently labeled biosealer was investigated using a confocal laser scanning microscope.

Results

The data were statistically analyzed using Kruskal-Wallis and Mann-Whitney tests (P = 0.05). The highest penetration of biosealer was observed in Group A, followed by Group B (P < 0.05).

Conclusions

Dentinal tubule penetration of biosealer was significantly improved by ultrasonic and sonic activation techniques.

Effect of conventional needle irrigation, passive ultrasonic irrigation, sonic irrigation and XP-endo finisher in removing intracanal Vitapex paste

To compare the efficiency of conventional needle irrigation, passive ultrasonic irrigation, sonic irrigation and XP-endo Finisher in removing Vitapex paste from root canals. The root canals of human single-rooted teeth were prepared and obturated with Vitapex paste. After 2 weeks, the 48 teeth were randomly allocated into four groups: conventional needle irrigation (CNI) group, passive ultrasonic irrigation (PUI) group, sonic irrigation (SI) group and XP-endo Finisher (XP) group. The specimens of four groups were scanned using a micro-computed tomography after the Vitapex pastes was removed. The results showed that more residual paste was left in the CNI group than in the other three groups (p < 0.05). There was no significant difference among the PUI, SI and XP group (p > 0.05). And, the majority of the residual Vitapex was found in the apical third, with a small amount in the middle third after using any of the three agitated irrigation techniques.

Evaluation of machine-assisted irrigation on removal of intracanal biofilm and extrusion of sodium hypochlorite using a three-dimensionally printed root canal model

PURPOSE

This study aimed to compare the biofilm removal and apical extrusion of sodium hypochlorite (NaOCl) following machine-assisted irrigation using a three-dimensionally (3D) printed dentin-insert model.

METHODS

Multispecies biofilms were formed in a 3D-printed curved root canal model with dentin insert. The model was then placed in a container that was filled with 0.2% agarose gel containing 0.1% m-Cresol purple. Root canals were irrigated with 1% NaOCl using syringe irrigation, sonically agitated (EndoActivator or EDDY) or ultrasonically activated (Endosonic Blue) irrigation. Samples were photographed and the color-changed area was measured. Biofilm removal was assessed using colony-forming unit counting, confocal laser scanning microscopic analysis and scanning electron microscopic observations. The data were analyzed using one-way ANOVA, followed by Tukey test (P < 0.05).

RESULTS

EDDY and Endosonic Blue demonstrated significantly greater reduction of biofilms compared to other groups. No significant differences were observed in the remaining biofilm volume in syringe irrigation and EndoActivator groups. Furthermore, EDDY and Endosonic Blue presented with numerous exposed dentinal tubules. EDDY showed significantly greater NaOCl extrusion compared to other groups.

CONCLUSION

Ultrasonic activation with a small-sized nickel-titanium file irrigation system may be beneficial in intracanal biofilm removal avoiding extrusion of NaOCl beyond the root apex.

Assessment of Irrigant Agitation Devices in Simulated Closed and Open Root Canal Systems

INTRODUCTION

The in vitro efficacy of irrigant activation devices has not been contrasted to their safety. This was attempted in this study using apically closed versus patent simulated root canal systems in epoxy resin models, with the latter featuring a simulated periapical lesion.

METHODS

All 72 models had 2 joining canals connected by an isthmus, which was filled with dentin debris. The simulated periapical lesion was filled with colored gelatin in the 36 respective models. Canals were irrigated with 1.3% sodium hypochlorite. Samples were divided into 4 subgroups per system (n = 9): conventional irrigation, sonic low (EndoActivator; Dentsply Sirona, Charlotte, NC) and high frequency (EDDY; VDW, Munich, Germany), and ultrasonic agitation of the irrigant (always applying 3 cycles of 20 seconds). The total cleared surface areas (mm²) in the simulated isthmus and periapical lesion were compared between systems and devices using parametric tests (P < .05).

RESULTS

The cleaning of the isthmus was more effective in the apically open compared with the closed systems and was also significantly influenced by the agitation method (P < .001). In the closed systems, EDDY and ultrasonic agitation achieved the significantly (P < .05) best cleaning of the isthmus. In the open systems, ultrasonic agitation showed the single best result (P < .05). EDDY caused by far the highest and ultrasonic agitation the lowest dissolution of the gelatin in the simulated periapical lesion.

CONCLUSIONS

Under the conditions of this study, ultrasonic agitation of a previously administered sodium hypochlorite irrigant was more laterally targeted and thus safer and more effective than sonic agitation methods.

Biofilm in Endodontics: In Vitro Cultivation Possibilities, Sonic-, Ultrasonic- and Laser-Assisted Removal Techniques and Evaluation of the Cleaning Efficacy

Incomplete and inadequate removal of endodontic biofilm during root canal treatment often leads to the clinical failure. Over the past decade, biofilm eradication techniques, such as sonication of irrigant solutions, ultrasonic and laser devices have been investigated in laboratory settings. This review aimed to give an overview of endodontic biofilm cultivation methods described in papers which investigated sonic-, ultrasonic- and Er:Yag laser-assisted biofilm removal techniques. Furthermore, the effectiveness of these removal techniques was discussed, as well as methods used for the evaluation of the cleaning efficacy. In general, laser assisted agitation, as well as ultrasonic and sonic activation of the irrigants provide a more efficient biofilm removal compared to conventional irrigation conducted by syringe/needle. The choice of irrigant is an important factor for reducing the bacterial contamination inside the root canal, with water and saline being the least effective. Due to heterogeneity in methods among the reviewed studies, it is difficult to compare sonic-, ultrasonic- and Er:Yag laser-assisted techniques among each other and give recommendations for the most efficient method in biofilm removal. Future studies should standardize the methodology regarding biofilm cultivation and cleaning methods, root canals with complex morphology should be introduced in research, with the aim of simulating the clinical scenario more closely.

Ultrasonic scaling in COVID-era dentistry: A quantitative assessment of aerosol spread during simulated and clinical ultrasonic scaling procedures

Objective

Healthcare agencies recommend limited use of aerosol‐generating procedures to mitigate disease (COVID‐19) transmission. However, total dispersion patterns of aerosols, particularly respirable droplets, via dental ultrasonic units is unclear. The purpose of this study was to characterize and map total spatter, droplet and aerosol dispersion during ultrasonic scaling in simulated and clinical contexts.

Methods

Ultrasonic scaling was performed on dental simulation units using methylene blue dye‐stained water. All resultant stain profiles were photoanalysed to calculate droplet size and travel distance/direction. Airborne particle concentrations were also documented 0–1.2 m (0–4ft.) and 1.2–2.4 m (4–8ft.) from patients during in vivo ultrasonic scaling with a saliva ejector.

Results

Stain profiles showed droplets between 25 and 50µm in diameter were most common, with smaller droplets closer to the mouth. In‐vivo particle concentrations were uniformly low. The smallest (<1 µm, PM1) and largest (>10 µm, PM10+) particles were most common, especially within 1.2 m (4ft.) of the patient. Respirable particles (PM2.5) were uncommon.

Conclusions

Tests showed the highest concentration of small droplets in zones nearest the patient. While uncommon, particles were detected up to 2.4 m (8ft.) away. Furthermore, observed particle sizes were consistent with those that can carry infectious agents. Efforts to mitigate the spread of inhalable aerosols should emphasize proximate regions nearest the procedure, including personal protective equipment and the use of evacuation devices.

Recent advances in portable devices for fruit firmness assessment

Fruit firmness is of vital importance in various links of the fruit supply chain, such as determining harvest time, choosing packaging and transportation methods, regulating storage conditions and predicting shelf life. Portable devices are useful tools to perform on-site measurements of fruit firmness to guide production, optimize processing procedures, improve handling practices and formulate supply strategies. This paper reviews the recent advances in the design and development of portable devices to evaluate fruit firmness based on sensing mechanical, sonic, vibrational and optical properties of fruits. The principle, structure, composition, application and performance of different portable devices are presented. Since each sensor has its merits and limitations, the integration of multiple microsensors to develop a miniaturized, low-cost and facile-operation device may achieve higher sensing performance in determining fruit firmness.

Comparison of irrigant activation devices and conventional needle irrigation on smear layer and debris removal in curved canals. (Smear layer removal from irrigant activation using SEM)

AIM

To compare the effectiveness of smear layer and debris removal in the final rinse of curved canals of permanent molars using different commercially available irrigant activation devices.

METHODS

The mesial roots of 74 extracted maxillary and mandibular molars were instrumented using the Mtwo nickel-titanium rotary system (VDW GmbH, Munich, Germany). They were then randomly assigned to one of three groups, varying in their final rinse protocol. Group 1 (n = 15) - conventional needle irrigation with 4% NaOCl; Group 2 (n = 19) - EndoActivator® (Dentsply Tulsa Dental Specialties, Tulsa, OK, USA) with 4% NaOCl; Group 3 (n = 17) - XP-endo® Finisher (FKG Dentaire SA, La Chaux-de-Fonds, Switzerland) with 4% NaOCl. After the final rinse, all canals were flushed with 1 mL 15% EDTA for 60 s and then flushed with saline. The roots were split longitudinally and prepared for scanning electron microscope imaging. ImageJ for Windows was utilised to assess the images for smear layer removal, while two blinded investigators assessed debris presence in the middle and apical thirds using a 5-point scale.

RESULTS

There was no significant difference in smear layer and debris removal between treatment and control groups in the same canal zones. A significant difference was noted across different canal zones both within and across the groups.

CONCLUSION

There is no statistically significant difference in effectiveness between activated irrigation techniques and manual activation. Further investigations are required to evaluate all methods available and determine the most efficient technique to irrigate successfully.

Comparative Analysis of Root Canal Filling Debris and Smear Layer Removal Efficacy Using Various Root Canal Activation Systems during Endodontic Retreatment

Background and objectives: The complete removal of obturation material can be a challenge in nonsurgical root canal retreatment. The insufficient removal of obturation material is a reason for root canal retreatment failure. Materials and Methods: The purpose of this study was to assess the efficacy of different final root canal irrigation activation methods in removing debris and smear layers in the apical and middle portions of root canals during retreatment. Sixty-six distal roots of freshly extracted molars were randomly divided into six groups: (1) primary root canal treatment with no obturation (negative control); (2) retreatment with only conventional instrumentation and irrigation (positive control); (3) retreatment with additional ultrasonic irrigation using the Piezon Master 700; (4) ultrasonic irrigation with the ENDOSONIC Blue; (5) sonic irrigation with the EDDY; and (6) multisonic irrigation with the GentleWave system. Roots were split and prepared for scanning electron microscopic (SEM) evaluation. Acquired images were assessed to quantify the amount of debris and smear remaining. Results: Among the treatment groups, Group 6 had a significantly lower debris score than Group 2 (positive control) in both the middle and apical regions (p = 0.004, p = 0.012). All treatment groups showed significantly lower smear scores than Group 2 in the middle and apical regions (p < 0.05). Conclusions: The GentleWave multisonic System showed a more optimal cleaning efficacy of the root canal debris but did not differ significantly with the tested passive ultrasonic or sonic irrigation method.

Role of Hedgehog Signaling in Breast Cancer: Pathogenesis and Therapeutics. Cells. 2019;8. [PMID: 31027259 DOI: 10.3390/cells8040375]

Breast cancer (BC) is the leading cause of cancer-related mortality in women, only followed by lung cancer. Given the importance of BC in public health, it is essential to identify biomarkers to predict prognosis, predetermine drug resistance and provide treatment guidelines that include personalized targeted therapies. The Hedgehog (Hh) signaling pathway plays an essential role in embryonic development, tissue regeneration, and stem cell renewal. Several lines of evidence endorse the important role of canonical and non-canonical Hh signaling in BC. In this comprehensive review we discuss the role of Hh signaling in breast development and homeostasis and its contribution to tumorigenesis and progression of different subtypes of BC. We also examine the efficacy of agents targeting different components of the Hh pathway both in preclinical models and in clinical trials. The contribution of the Hh pathway in BC tumorigenesis and progression, its prognostic role, and its value as a therapeutic target vary according to the molecular, clinical, and histopathological characteristics of the BC patients. The evidence presented here highlights the relevance of the Hh signaling in BC, and suggest that this pathway is key for BC progression and metastasis.

Comparison of the antibacterial efficacy of sonic- and two ultrasonic-activated irrigation techniques in reducing intracanal Enterococcus faecalis populations

OBJECTIVE

This in-vitro study evaluated the antibacterial efficacy of sonic and ultrasonic irrigation with either intermittent or continuous flush in root canals infected with Enterococcus faecalis.

METHOD AND MATERIALS

Seventy single-rooted, extracted teeth with straight root canals were prepared with FlexMaster NiTi-instruments, sterilized, inoculated with E faecalis and incubated for 72 hours. Sixty roots were randomly divided into four experimental groups as well as into infection and sterile controls (n = 10 each). The remaining teeth were used for SEM analysis of smear layer removal (n = 5) and infection with E faecalis (n = 5). Irrigation in the experimental groups was performed with 1% NaOCl and syringe irrigation, sonic activation of the irrigant with EndoActivator, ultrasonic activation with intermittent flush, or ultrasonic activation with continuous flush. Microbial sampling was performed by collecting dentin shavings from the root canal walls. Colony-forming units were counted and statistical analysis was performed using nonparametric rank-based ANOVA-type tests for longitudinal data (P < .05).

RESULTS

A significant reduction of E faecalis of 3 log10 steps compared to the infection control was achieved by all irrigation techniques (P < .0001). There were no significant differences in antibacterial efficacy between syringe irrigation, sonically, or ultrasonically activated irrigation (P > .45).

CONCLUSION

Activation of 1% NaOCl with either sonic or ultrasonic devices did not increase the antimicrobial efficacy against E faecalis compared to conventional syringe irrigation in straight root canals.

Micro-CT evaluation of sonically and ultrasonically activated irrigation on the removal of hard-tissue debris from isthmus-containing mesial root canal systems of mandibular molars

AIM

To evaluate the efficacy of sonically and ultrasonically activated irrigation on removal of accumulated hard-tissue debris (AHTD) in mesial root canal systems of mandibular molars using micro-computed tomographic (micro-CT) analysis.

METHODOLOGY

Forty mesial roots of mandibular molars with two independent canals joined apically by an isthmus (Vertucci type II) were selected. The root canals were instrumented using Reciproc R25 instruments, and specimens were scanned at a resolution of 10.5 μm. Subsequently, n = 10 roots were assigned to each of the four final irrigation groups such that the group means and variances were almost identical: sonically activated irrigation with EndoActivator (EA) or EDDY (ED), ultrasonically activated irrigation (UAI) and manual irrigation without activation (MI). The final irrigation procedures were performed using a total of 5 mL 1% NaOCl and 5 mL 15% EDTA per canal over 5 min with activation time of 4 × 20 s. Reconstructed data sets were coregistered, and the mean percentage reduction of AHTD after final irrigation was compared statistically between groups using analysis of variance at a significance level set at 5%.

RESULTS

A significant reduction of AHTD was achieved after final irrigation in all groups (P < 0.05), ranging from 44.1% to 66.8%. The vol% of debris after irrigation was 3.7 ± 1.9% for EA, 3.3 ± 2.3% for ED, 2.1 ± 1.6% for UAI and 4.4 ± 2.3% for MI, with no significant difference between groups (P > 0.05).

CONCLUSIONS

None of the final irrigation protocols completely removed AHTD from mesial root canal systems in extracted human mandibular molars. Sonically and ultrasonically activated irrigation performed no better compared to manual irrigation.

A Comparison of the Effect of Two Power Toothbrushes on the Reduction of Gingival Inflammation and Supragingival Plaque

OBJECTIVES

To compare the effect of the Philips Sonicare DiamondClean Smart and Oral-B Genius 8000 powered toothbrushes on gingivitis, gingival bleeding, and supragingival plaque reduction following 42 days of home use.

METHODS

This was a randomized, parallel, examiner-blinded, prospective clinical trial with two treatment groups. Eligible participants were generally healthy volunteers who were manual toothbrush users, non-flossers, 18-65 years of age. The subject panel included non-smokers with = 50 sites of gingival bleeding according to the Gingival Bleeding Index (GBI), and a supragingival plaque score of = 1.8 per Modified Plaque Index (MPI) at 3-6 hours following last tooth brushing encounter. Eligible subjects were randomized to use either a Philips Sonicare DiamondClean Smart with Premium Plaque Control brush head (DCS) or an Oral-B Genius 8000 with FlossAction brush head (OBG) for home use. Each toothbrush was used twice daily for two minutes. All subjects used a standardized fluoride-containing dentifrice. All other oral hygiene measures were prohibited. Subjects returned at Day 14 for an interim compliance and safety assessment, and at Day 42 for the final safety and efficacy assessments.

RESULTS

Of 222 enrolled and eligible subjects, 219 completed (112 in the SDC group, 107 in the OBG group) the study. The least squares (LS) mean and 95% confidence interval (CI) estimates for gingivitis reduction and percent reduction per Modified Gingival Index (MGI) following 42 days of product home use were 1.38 (1.30, 1.46) and 51.32% (48.45%, 54.19%) for DCS, and 0.53 (0.45, 0.61) and 20.07% (17.14%, 23.00%) for OBG. The differences, expressed as either reduction or percent reduction, were statistically significant between the two groups, p < 0.001. Statistically significant differences were also observed between products at Day 42 for the gingival bleeding and supragingival plaque reduction endpoints, p < 0.001. There were two reported adverse events.

CONCLUSIONS

The Philips Sonicare DiamondClean Smart powered toothbrush reduced gingival inflammation, gingival bleeding, and supragingival plaque significantly more than the Oral-B Genius 8000 powered toothbrush following a 42-day home-use period. Both products were safe for use.

The Effect of Use of a Sonic Power Toothbrush and a Manual Toothbrush Control on Plaque and Gingivitis

OBJECTIVES

To compare the ability of the Philips Sonicare DiamondClean power toothbrush and the ADA Reference manual toothbrush to reduce plaque and gingival inflammation by routine manual toothbrush users.

METHODS

This was a randomized, single-blind, parallel-design study. Eligible subjects were generally healthy non-smokers who exhibited mild to moderate gingivitis upon study entry. Enrolled subjects were randomly allocated to commence twice-daily home use of either a Philips Sonicare DiamondClean (DiamondClean) power toothbrush or an ADA reference manual toothbrush (MTB) for a period of four weeks. Clinical safety and efficacy were assessed after a two- and four-week period of home use. Statistical analysis was performed for the modified intent to treat (mITT) population using a mixed model with the Baseline score as a covariate.

RESULTS

A total of 182 volunteers were screened, 144 (72 per treatment) were randomized, and 142 subjects completed this study. Following four weeks of use, the Least Square (LS) Mean SE) percent reduction in surface plaque was 34.9% (1.8) for DiamondClean and 8.0% (1.7) for MTB, (p < 0.0001). At the same four-week time point, the LS Mean (SE) percent reduction in gingival inflammation for DiamondClean was 25.5% (1.9) and 19.1% (1.9) for MTB (p = 0.0213). For gingival bleeding, the LS Mean (SE) percent reduction in sites with gingival bleeding for DiamondClean was 57.4% (3.06) and 31.4% (3.04) for MTB (p < 0.0001).

CONCLUSIONS

The Philips Sonicare DiamondClean power toothbrush was statistically significantly more effective than a manual toothbrush in reducing supragingival plaque, gingival inflammation, and gingival bleeding following a four-week period of home use. Both products were safe for home use.

An Evaluation of Plaque and Gingivitis Reduction Following Home Use of Sonicare FlexCare Platinum with Premium Plaque Control Brush Head and a Manual Toothbrush

OBJECTIVES

To assess the effect of the Philips Sonicare FlexCare Platinum with Premium plaque control brush head on gingival inflammation, bleeding, and supragingival plaque reduction following a six-week period of home use compared to a manual toothbrush.

METHODS

This was a randomized, single-blind, parallel-design clinical trial. Subjects included in the study were routine manual toothbrush users who were generally healthy non-smokers, aged 18-65 years, with mild to moderate gingivitis. Subjects with advanced periodontal disease, excessive gingival recession, and heavy deposits of calculus or rampant decay were excluded from the study. Eligible participants were dispensed either Philips Sonicare FlexCare Platinum with Premium plaque control brush head (PC), or an ADA Reference manual toothbrush (MTB) for twice-daily home oral hygiene procedures for six weeks. Efficacy measures included the Lobene and Soparker Modification of Quigley and Hein Plaque Index (MPI), the Modified Gingival Index (MGI), and Gingival Bleeding Index (GBI). Safety was evaluated by oral examination and subject report. Efficacy and safety were assessed at Baseline, and at two and six weeks following product home use.

RESULTS

Of 154 subjects randomized, 143 subjects completed the study. For the primary endpoint, MGI at Week 2, statistically significantly larger reductions in MGI were observed for PC versus MTB, p < 0.0001. The adjusted mean reduction and standard error estimates (SE) for MGI, expressed as percent reduction versus Baseline to Week 2, were 41.73% (2.00%) for PC and 7.38% (2.02%) for MTB. Statistically significant differences were also observed for MPI and GBI at Week 2, and for all metrics at Week 6.

CONCLUSIONS

Philips Sonicare FlexCare Platinum with Premium plaque control brush head statistically significantly reduces gingival inflammation, gingival bleeding, and plaque following two and six weeks of home use, compared to manual tooth brushing alone.

A Comparison of the Effect of Two Power Toothbrushes on the Gingival Health and Plaque Status of Subjects with Moderate Gingivitis

OBJECTIVES

To compare the effect of the Philips Sonicare DiamondClean plus Premium plaque control brush head with the Oral-B 7000 plus CrossAction brush head on gingivitis and supragingival plaque reduction following a 42-day period of home use.

METHODS

This was a randomized, parallel, examiner-blind, prospective clinical trial conducted on generally healthy subjects. Eligible subjects met the following eligibility criteria: age 18-65, non-smoker, routine manual toothbrush user, ≥ 50 sites of gingival bleeding per the Gingival Bleeding Index (GBI), and ≥ 1.8 plaque score per the Modified Plaque Index (MPI), assessed three to six hours following the last oral hygiene procedure. Eligible subjects were enrolled in the study and randomly assigned to use either a Philips Sonicare DiamondClean with Premium plaque control brush head power toothbrush (SPC) or an Oral-B® 7000 with CrossAction™ brush head power toothbrush (OCA), for twice daily home use over a period of 42 days. All subjects were dispensed a standard fluoride-containing dentifrice and both toothbrushes were to be used in their respective Deep Clean modes. Safety and efficacy evaluations were performed at 14 and 42 days following Baseline.

RESULTS

Two-hundred eighty-four subjects completed this trial (142 subjects per treatment group). Least squares mean (95% CI) estimates for reduction and percent reduction of gingivitis per Modified Gingival Index (MGI) following 42 days of product use for the SPC group were 1.17 (1.10, 1.24) and 45.68% (42.95%, 48.40%); for the OCA group they were 0.69 (0.62, 0.76) and 26.83% (24.10%, 29.56%). The mean difference (95% CI) between the two treatment groups was 0.48 (0.38, 0.58) and 18.85% (14.99%, 22.70%) for reduction and percent reduction, respectively. The lower limit of the 95% CI for the difference in Overall score between the two treatment groups was greater than the predefined non-inferiority margin (i.e., -0.10 or -5%); therefore SPC was declared non-inferior to OCA. In addition, since the 95% CI for the difference did not include zero, SPC was declared superior to OCA in the reduction of gingivitis per MGI at Day 42 (p-value < 0.0001). Similarly, for MGI at Day 14 and for GBI and MPI at Day 14 and Day 42, significantly larger reductions were observed for SPC compared to OCA (p-value < 0.0001).

CONCLUSIONS

Philips Sonicare DiamondClean with Premium plaque control brush head (SPC) was statistically superior to the Oral-B 7000 with CrossAction brush head (OCA) in reducing gingival inflammation, gingival bleeding, and supragingival plaque following 14 and 42 days of home use. Both products were safe for use.

Cavitation measurement during sonic and ultrasonic activated irrigation

INTRODUCTION

The aims of this study were to quantify and to visualize the possible occurrence of transient cavitation (bubble formation and implosion) during sonic and ultrasonic (UAI) activated irrigation.

METHODS

The amount of cavitation generated around several endodontic instruments was measured by sonochemiluminescence dosimetry inside 4 root canal models of human dimensions and varying complexity. Furthermore, the spatial distribution of the sonochemiluminescence in the root canal was visualized with long-exposure photography.

RESULTS

Instrument oscillation frequency, ultrasonic power, and file taper influenced the occurrence and amount of cavitation. In UAI, cavitation was distributed between the file and the wall extending beyond the file and inside lateral canals/isthmuses. In sonic activated irrigation, no cavitation was detected.

CONCLUSIONS

Cavitation was shown to occur in UAI at clinically relevant ultrasonic power settings in both straight and curved canals but not around sonically oscillating instruments, driven at their highest frequency.