Update of the therapeutic planning of irrigation and intracanal medication in root canal treatment. A literature review

Development of clobetasol-loaded biodegradable nanoparticles as an endodontic intracanal medicament

AIM

The aim of current study is the development and optimization of biodegradable polymeric nanoparticles (NPs) to be used in the field of Endodontics as intracanal medication in cases of avulsed teeth with extended extra-oral time, utilizing PLGA polymers loaded with the anti-inflammatory drug clobetasol propionate (CP).

METHODOLOGY

CP-loaded nanoparticles (CP-NPs) were prepared using the solvent displacement method. CP release profile from CP-NPs was assessed for 48 h against free CP. Using extracted human teeth, the degree of infiltration inside the dentinal tubules was studied for both CP-NPs and CP. The anti-inflammatory capacity of CP-NPs was evaluated in vitro measuring their response and reaction against inflammatory cells, in particular against macrophages. The enzyme-linked immunosorbent assay (ELISA) was used to examine the cytokine release of IL-1β and TNF-α.

RESULTS

Optimized CP-NPs displayed an average size below 200 nm and a monomodal population. Additionally, spherical morphology and non-aggregation of CP-NPs were confirmed by transmission electron microscopy. Interaction studies showed that CP was encapsulated inside the NPs and no covalent bonds were formed. Moreover, CP-NPs exhibited a prolonged and steady release with only 21% of the encapsulated CP released after 48 h. Using confocal laser scanning microscopy, it was observed that CP-NPs were able to display enhanced penetration into the dentinal tubules. Neither the release of TNF-α nor IL-1β increased in CP-NPs compared to the LPS control, displaying results similar and even less than the TCP after 48 h. Moreover, IL-1β release in LPS-stimulated cells, decreased when macrophages were treated with CP-NPs.

CONCLUSIONS

In the present work, CP-NPs were prepared, optimized and characterized displaying significant increase in the degree of infiltration inside the dentinal tubules against CP and were able to significantly reduce TNF-α release. Therefore, CP-NPs constitute a promising therapy for the treatment of avulsed teeth with extended extra-oral time.

Evaluation of baghdadite (Ca3ZrSi2O9) cements for the application as novel endodontic filling materials

OBJECTIVES

Baghdadite (Ca3ZrSi2O9) cements of various composition have been investigated in this study regarding an application as endodontic filling materials.

METHODS

Cements were either obtained by mixing mechanically activated baghdadite powder with water (maBag) or by subsequently substituting the ß-tricalcium phosphate (ß-TCP) component in a brushite forming calcium phosphate cement. The cements were analyzed for their mechanical performance, injectability, radiopacity, phase composition and antimicrobial properties.

RESULTS

The cements demonstrated sufficient mechanical performance with a compressive strength of ∼1 MPa (maBag) and 2.3 - 17.4 MPa (substituted calcium phosphate cement), good injectability > 80 % depending on the powder to liquid ratio and an intrinsic radiopacity of 1.13 - 2.05 mm aluminum equivalent. Immersion in artificial saliva proved their bioactivity by the formation of calcium phosphate and calcium silicate precipitates on the cement surface. The bacterial activity of Staphylococcus aureus cultured on the surface of the cements was found to be similar compared to clinical standard ProRoot MTA cement or even reduced by a factor of 3 for Streptococcus mutans.

SIGNIFICANCE

In combination with their antibacterial properties, baghdadite cements are thought to have the potential to fulfil the clinical requirements for endodontic filling materials.

Adhesion and sealing of different universal adhesive systems associated with bulk-fill resins after using endodontic irrigation solutions: An in vitro study

This study aimed to evaluate the interface of universal adhesive (UA) with bulk-fill resin (BF) and dentin, after endodontic irrigation. The pulp chamber of 96 molars was irrigated with chlorhexidine 2% (CHX) or sodium hypochlorite 5.25% (NaOCl) and restored according to three restorative protocols. Microtensile bond strength (μTBS) and nanoleakage tests were performed after 24 h of thermocycling. Kruskal Wallis, Mann-Whitney and Wilcoxon were performed (p < 0.05). Comparing restorative systems, a difference was found only when irrigated with CHX after 24 h. CHX provided higher μTBS than NaOCl after 24 h for two restorative protocols; after thermocycling, NaOCl provided the greatest μTBS than CHX for one group. Decreased μTBS was observed for all restorative systems when CHX was used after thermocycling. NaOCl demonstrated the highest nanoleakage. The composition of UA influenced the immediate adhesion and sealing to BF when CHX was used; ageing has a deteriorating effect on adhesion and sealing for all restorative systems.

Can diode laser 810 nm decrease post endodontic pain in patients with asymptomatic necrotic maxillary incisors? A four-arm randomized controlled trial

AIM

To find the best method for applying the diode laser 810 nm to relieve post-endodontic pain on necrotic maxillary incisors with periapical lesions within a single-visit treatment.

METHODS

Eighty patients with a necrotic incisor, diagnosed with asymptomatic apical periodontitis, received standardized cleaning and shaping procedures, then divided randomly with a 1:1:1:1 allocation ratio into four groups: Group 1: control group with no laser application, Group 2: applying the diode laser as an irrigation activation system (IAS), Group 3: applying the diode laser from the buccal and palatal mucosa, Group 4: applying the diode laser as an IAS and from buccal and palatal mucosa. The postoperative pain was assessed using the visual analog scale (VAS) 1, 3, 7, and 14 days after the treatment. The mean values of the VAS score were statistically analyzed used Kruskal-Walis and Mann-Whitney U tests. The level of significance was set at a = 0.05.

RESULTS

During 14 days after treatment, there was a statistically significant difference between mean values of VAS scores in the four groups (P value < 0.05); Group 1 scored the highest score, whereas Group 4 showed the lowest one. Moreover, Group 4 showed favorable outcomes compared with Group 2 and Group 3 during the first three days after treatment.

CONCLUSION

Diode laser reduced postoperative pain after necrotic teeth with large-sized apical lesion treatment, whereas using diode laser either as an IAS or LLLT reduced the postoperative pain compared with the control group. Moreover, the usage of a diode laser in both previous techniques represents the best protocol for postoperative pain relief during 14 days of treatment.

CLINICAL RELEVANCE

The clinical significance of this study is to investigate the best method to reduce postoperative pain using diode lasers 810 nm; where the results of this study indicated that the more diode laser exposer in LLLT and IAS, the less postoperative pain after endodontic procedures.

Influence of systemic antibiotic therapy on the development and progression of induced apical periodontitis in Wistar rats

The aim of this study was to investigate the influence of systemic antibiotic therapy on the development and progression of induced apical periodontitis (AP) in Wistar rats. Fifty-six rats were submitted to pulp exposure of the lower left first molar for the induction of AP. On the same day, intraperitoneal antibiotic therapy was administered once a day, for 15 days, until euthanasia. The groups were formed according to the different treatments (n = 8): C-control; GEN-treated with gentamicin (10 mg/Kg); AC-treated with amoxicillin (100 mg/Kg); MZ-treated with metronidazole (40 mg/Kg); AMP-treated with ampicillin (100 mg/Kg); AMC group-treated with amoxicillin + clavulanic acid (100 mg/kg); CLI-treated with clindamycin (60 mg/kg). After euthanasia, the jaws were collected and processed for (1) histological and histometric analysis using hematoxylin and eosin staining, (2) analysis of collagen fibers using Picrosirius Red staining and (3) bacteriological analysis using Brown-Brenn staining. The data were analyzed statistically (p < 0.05). AP induction was confirmed in all groups. The AMC group had the lower intensity of inflammatory infiltrate (p = 0.028) and less periapical bone resorption compared to control (p = 0.006). Regarding collagen maturation, PSR staining revealed a predominance of mature collagen fibers in all groups. The AC and AMC groups had the lower amount of mature fibers and the highest amount of immature fibers, compared to all other groups (p < 0.001). All groups showed bacterial contamination; however, the AC and AMC groups showed a lower extent of bacterial contamination compared to the control (p < 0.001). It can be concluded that systemic antibiotic therapy influences the development and progression of induced AP.

Iontophoresis use for increasing drug penetration into root canals and dentinal tubules: A proof-of-concept study

INTRODUCTION

The success of endodontic treatment depends on the significant disinfection of the root canal system, its irregularities, and dentinal tubules. However, achieving complete disinfection remains challenging, with frequent failures and occurrence of secondary infections. Here, we propose using iontophoresis to increase the penetration and distribution of disinfecting agents into root canals, using methylene blue for proof-of-concept.

METHODS

The marker was applied in bovine root canals, and the radial distribution of the dye in the dentinal tubules was evaluated by optical microscopy. Iontophoresis was applied at 0.5 and 1.5 mA for 5 and 15 min.

RESULTS

A significant statistical difference (p < 0.05) was observed in the marker penetration between passive and iontophoretic applications. Both current density and application time had an important effect on methylene blue distribution, with a greater efficacy delivery to the apical region achieved after 1.5 mA for 5 min or 0.5 mA for 15 min, showing longer application time can compensate for lower application current.

CONCLUSION

Iontophoresis increases the penetration and distribution of methylene blue into bovine root canals and dentinal tubules, including its innermost portions.

CLINICAL SIGNIFICANCE

Iontophoresis has shown to be a promising technique for root canal and dentinal tubule disinfection.

Survival of severely compromised endodontically treated teeth restored with or without a fiber glass post

OBJECTIVE

The use of a fiber glass post (FGP) type and choice of FGP diameter to restore endodontically treated incisors without ferrule is controversial. This study evaluated survival rate and failure mode of severely compromised central incisors without ferrule rehabilitated using resin-based composite (RBC) with or without FGP with different diameters.

METHODOLOGY

A total of 60 decoronated bovine incisors without a ferrule were endodontically treated and prepared for 1.4, 1.6, and 1.8 mm diameter FGPs (Whitepost System DC 0.5, Fit 0.4, and DCE 0.5; FGM). Half of the teeth received FGPs cemented using dual-cure resin cement (Allcem Core; FGM), the other half were filled using only bulk-fill RBC (OPUS Bulk Fill; FGM). The crowns were directly restored with RBC. The roots were embedded in polystyrene resin and the periodontal ligament was simulated with polyether impression material. Fatigue testing was conducted under 5 Hz cyclic loading at 30 degrees to the incisal edge, beginning at 50 N (5,000 cycles) as a warmup. After, the load was increased 100 N every 15,000 cycles until fracture occurred. All specimens were subjected to transillumination, micro-CT analysis, and digital radiography before and after fatigue testing. Fracture mode was classified according to severity and repair potential. Data were analyzed with Kaplan-Meier survival test and post hoc log-rank test (α=0.05) for pairwise comparisons.

RESULTS

Using FGP significantly increased the number of cycles to failure, irrespective of FGP diameters (p=0.001). The FGP diameters had no statistically significant effect on cycles to failure or failure mode.

CONCLUSION

Using FGP without ferrule improved survival rate of structurally severely compromised central incisors compared with rehabilitation without FGP. The diameter of the FGPs had no effect on the survival rate and failure mode.

The effect of the irrigant activation protocol on postoperative pain in maxillary incisors with asymptomatic apical periodontitis: A three-arm randomized clinical trial

OBJECTIVES

This study aimed to compare the effects of three irrigation activation systems (IAS) on postoperative pain (PP) in activating three final irrigants: sodium hypochlorite 5.25%, ethylenediaminetetraacetic acid 17%, and chlorhexidine 2%.

MATERIALS AND METHODS

This parallel randomized clinical trial included referred patients with asymptomatic large-sized apical lesion incisors. A standard method was followed in the canal cleaning and shaping for all included patients in the study. Then, the patients were randomly assigned (1:1 allocation) into three groups: G1 (n = 20) with passive ultrasonic irrigation activation; G2 (n = 20) with XP-Endo Finisher file activation; and G3 (n = 20) with diode laser (810 nm) activation. PP was estimated in all groups using a visual analog scale after 1, 3, 7, and 14 days of treatment. Comparisons between the groups were made using the Kruskal-Wallis test, whereas the Mann-Whitney U test was used in the pairwise comparisons.

RESULTS

Sixty patients were followed-up in this trial. There were significant differences between the groups in terms of PP After 1, 3, and 7 days of treatment (p = 0.002, p = 0.017, and p = 0.006, respectively). On the first day of treatment, G3 showed the lowest PP compared with G1 and G2 (p = 0.007 and p = 0.001, respectively). On the third day of treatment, G3 showed less PP compared with G2 (p = 0.005). On the seventh day of treatment, G2 showed the highest PP compared with G1 and G3 (p = 0.012 and p = 0.003, respectively).

CONCLUSIONS

The XP-Endo Finisher file caused the highest PP level especially in the next day and 3 days of the treatment, whereas the diode laser had the lowest PP level during the first week of treatment. It is noteworthy that PP disappeared completely after 2 weeks of treatment with all three IASs.

TRIAL REGISTRATION

The trial was registered in the ISRCTN registry (Trial ID: SRCTN99457940).

Enterococcus faecalis in secondary apical periodontitis: Mechanisms of bacterial survival and disease persistence

Enterococcus faecalis is a commensal bacterium commonly found in the human gastrointestinal tract. However, in individuals with compromised immune systems, the pathogen can lead to severe illness. This opportunistic pathogen is associated with secondary apical diseases and is adept at resisting antibiotics and other forms of treatment because of its numerous virulence factors. Enterococcus faecalis is capable of disrupting the normal functions of immune cells, thereby hindering the body's ability to eradicate the infection. However, intensive research is needed in further understanding the adverse immunomodulatory effects of E. faecalis. Potential strategies specific for eradicating E. faecalis have proven beneficial in the treatment of persistent secondary apical periodontitis.

Successful outcome of permanent maxillary incisor reimplanted after 30 hours of extra-oral time-a case report with 5-year follow-up

Key Clinical Message

Tooth reimplantation should be attempted in every possible case with thorough disinfection and impervious obturation. Integration of progressive innovations with recommended protocols can enhance complication free survival in intense situations.

Abstract

The present case describes the unique successful outcome of a tooth reimplanted after the delay of 30 hours. A 21-year old male patient presented with an avulsed #21 after a fall due to electric shock. It was reimplanted according IADT guidelines with the addition of specific irrigation sequence proposed for regenerative endodontic procedures during the endodontic treatment. The final obturation was accomplished by combination of Biodentine and BioRCS root-canal sealer. Subluxated #11 developed symptoms at 6 months and was further managed using recommended endodontic procedure. Both teeth had complication free survival during 5 year follow-up.

A Novel Endodontic Approach in Removing Smear Layer Using Nano and Submicron Diamonds with Intracanal Oscillation Irrigation

Sodium hypochlorite (NaOCl) and ethylenediaminetetraacetic acid (EDTA) are commonly recommended for effectively removing organic and inorganic components in the smear layer. This layer is found on root canal walls after root canal instrumentation. However, high-concentration EDTA reduces the strength of dentin and the dissolution efficacy of organic substances in NaOCl solution. The objective of this study was to investigate the efficacy of applying nano and submicron diamonds in irrigation solutions with sonic and ultrasonic oscillation for removing the smear layer during endodontic treatment. Extracted single-rooted human teeth were instrumented with ProTaper^® Gold (Dentsply Sirona) nickel-titanium rotary instruments. Subsequently, each canal was irrigated with 3% NaOCl, 17% EDTA, distilled water, and 10-1000 nm-sized nano and submicron diamond irrigation solutions, respectively. Sonic and ultrasonic instruments were compared for oscillating the irrigation solutions. The teeth were processed for scanning electron microscopy to observe the efficiency of smear layer removal on the canal walls. Our results indicated that diamond sizes of 50 nm and above irrigation solutions showed significant effectiveness in removing the smear layer following the oscillation of sonic instruments for 10 s. Ultrasonic assisted 500 nm and 1000 nm diamond solutions significantly differed from the other diamond-sized solution in their ability to remove the smear layer. These results suggest that sonic and ultrasonic oscillation with specific sizes of nano and submicron diamond irrigation solution can be used as an alternative approach to removing the smear layer during endodontic treatment. The potential clinical application of root canal treatments can be expected.

Transient apical peak pressure measurement of Er:YAG laser-activated irrigation in different in vitro tooth models using a high-frequency sensor system

The transient apical pressure side effect is an important safety consideration for Er:YAG laser-activated irrigation (LAI). Therefore, this study aimed to measure the transient apical peak pressure (TAPP) of LAI under different laser settings in various tooth models using a high-frequency sensor system. Tooth models with different pulp chamber structures, apical diameters, and curvatures were prepared using transparent resin and filled with deionised water. The Er:YAG laser fibre was placed 3 mm from the root canal orifice. Irrigation was performed at 10-40 mJ and 20-50 Hz using the super short pulse mode. The TAPP was measured using a 50,000-sample/second pressure sensor connected to the models' apices. The TAPP of LAI was significantly higher than that of other chemical preparation methods. Among all investigated factors, pulp chamber anatomy and apical diameters had the greatest effects and were highly related to the apical peak pressure. Root canal curvature showed no direct correlation with TAPP. The larger the final prepared working width, the greater the TAPP. Furthermore, both pulse energy and frequency had positive correlations with TAPP. In conclusion, tooth anatomy factors and laser parameter settings influenced TAPP during Er:YAG LAI. Therefore, proper settings of laser parameters are important to improve the safety of Er:YAG LAI.

Effect of different root canal irrigants on push-out bond strength of two novel root-end filling materials

BACKGROUND

The aim of this in vitro study was to evaluate push-out bond strength of different root-end filling materials using various irrigant solutions.

METHODS

A push-out bond strength test was performed to evaluate the bond strength of two experimental root-end filling materials: namely, nano-hybrid mineral trioxide aggregate (MTA) and polymethyl methacrylate (PMMA) cement filled with 20% weight nano hydroxyapatite (nHA) fillers compared to conventional MTA. The irrigant solutions employed were sodium hypochlorite (NaOCl) in concentrations 1%, 2.5% and 5.25% and 2% chlorhexidine gluconate (CHX) followed by application of 17% ethylene diamine tetra-acetic acid (EDTA). A freshly extracted sixty single-rooted human maxillary central incisors were used. The crowns were removed, the canal apex was widened to simulate immature teeth. Each type of irrigation protocols was performed. After application and setting of the root-end filling materials, a slice of one mm thickness was cut transversely from the apical end of each root. Specimens were stored for 1 month in artificial saliva and were subjected to a push-out test to evaluate the shear bond strength. Data were analyzed using two-way ANOVA and Tukey test.

RESULTS

The experimental nano-hybrid MTA showed the highest significant push-out bond strength values when irrigated by NaOCl at several concentrations (1%, 2.5% and 5.25%) (P< 0.05). Meanwhile, irrigation with 2% CHX resulted in highest bond strength values in nano-hybrid white MTA (18 MPa) and PMMA filled with 20% weight nHA (17.4 MPa) with nonsignificant difference between them (p = 0.25). In each root-end filling material, irrigation with 2% CHX led to the highest significant bond strength, followed by NaOCl 1%, while the least significant bond strength was produced after irrigation with NaOCl 2.5% and 5.25% (P< 0.05).

CONCLUSION

Considering the limitations of this study, it may be concluded that the application of 2% CXH and 17% EDTA provides superior push-out bond strength to root canal dentin compared with irrigation with NaOCl irrigants and 17% EDTA, experimental nano-hybrid MTA root-end filling material provides enhanced shear bond strength than conventional micron-sized MTA root-end filling material.

Cauterization of Narrow Root Canals Untouched by Instruments by High-Frequency Current

The mechanical removal of bacteria is fundamental to the treatment of infected root canals, but complete sterilization of biofilms tends not to extend to uninstrumented areas. However, during electrical conduction to a root canal filled with a conductor, the higher impedance where the root canal is narrower generates Joule heat that may result in a large temperature increase and sterilization. The effect of a high-frequency electric current on the wall of a simulated narrow root canal was investigated by scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS). Simulated root canals, 0.1 mm in diameter, were prepared in dentine blocks. The root canal wall was treated with Plank-Rychlo solution for 5 min to create a decalcified layer. The simulated root canal was filled with either saline or NaClO, and 150 or 225 V at 520 kHz was applied for 0 s, 1 s, or 5 s. As the conduction time increased, and when the saline was replaced with NaClO, the proportion with a flat decalcified surface decreased, dentinal tubules and a lava-like morphology were significantly more evident on SEM (p < 0.01), and EDS showed significant decreases in carbon and oxygen and increases in calcium (p < 0.01). It was concluded that filling uninstrumented root canals with NaClO and using electrical conduction for 5 s could incinerate and eliminate the organic material of the root canal wall. The application of high-frequency electric current may lead to the cure of many cases of persistent apical periodontitis.

Update on citric acid use in endodontic treatment: a systematic review

This systematic review aims to analyse the available evidence concerning the use of citric acid (CA) in endodontics treatment and to assess its results in terms of different considerations: effect on smear layer removal, influence on sealer bond strength, activation effect by means of sonic or ultrasonic devices, effects on dentine surface, antibacterial activity, and effectiveness boost for regenerative procedures, releasing growth factors from dentin. To evaluate the results of CA as a final irrigant and compare them to other chelating agents. This review followed the PRISMA checklist. An electronic search was conducted in MEDLINE (OVID), Scopus (Elsevier) and the Web of Science (Thomson Reuters) databases. Risk of bias of included studies was evaluated using the modified CONSORT checklist and the PRIRATE checklist 2020 guidelines. 39 studies fulfilled the eligibility criteria to be included in this review: 27 in vitro studies using extracted human teeth, 10 in vitro studies using human dentin disks, and 2 RCT. Citric acid has proven to be effective in smear layer removal, showing better results in coronal and middle root thirds, improving its effect when combined with manual dynamic activation. There is no agreement regarding citric acid effect on sealer adhesion and adaptation to root canal walls due to heterogeneity within studies. Citric acid irrigation can decrease dentine microhardness and cause decalcification and erosion, especially when used before NaOCl. Citric acid has proven to be beneficial in regenerative endodontic procedures due to higher TGF-β1 release.Trial registration: Prospero database CRD42021267055.

Assessment of Dentinal Tubules Penetration by Hyben X Delivered into the Root Canal System as an Irrigant; An in Vitro Study

Introduction

Disinfection of the root canal system is crucial for a successful endodontic treatment. Several factors influence the performance of effective irrigation. Diverse irrigating substances have been used but none has proved to completely penetrate the root canal system. HybenX dries biofilm due to its hygroscopic properties; therefore, it is effective in the treatment of biofilm-related diseases. This investigation aimed to estimate HybenX's degree of penetration into the dentinal tubules of upper first premolars.

Materials and Methods

Experimental in vitro intervention where 30 extracted maxillary premolars were evaluated to determine HybenX's degree of penetration and 5% sodium hypochlorite in the dentinal tubules using three different irrigation techniques (passive ultrasonic irrigation, dynamic manual irrigation and conventional single jet irrigation technique). After preparation, the root canals were irrigated with fluorescent rhodamine 6G; then 500-micrometer sections were made to be analyzed under a fluorescence microscope. Measurements were made in micrometer in ZEN software to determine the penetration degree of each substance in the different root thirds.

Results

In the apical third, significant differences between the 3 irrigation techniques were found (P<0.05), similarly, for the middle and cervical thirds. Significant statistical differences between the HybenX and sodium hypochlorite were found at the cervical and middle levels when using the conventional Monoject irrigation and passive ultrasonic irrigation techniques. As for the apical level, differences were found between the passive ultrasonic irrigation techniques and the dynamic manual irrigation technique.

Conclusions

Based on this in vitro study, HybenX proved to highly penetrate into the dentinal tubules, especially when using the passive ultrasonic irrigation technique. HybenX may be a useful option for root canal irrigation in endodontics.

Comparative Assessment of Novel Collagen Cross-linking Agents on Push-out Bond Strength of Two Different Sealers: An In Vitro Study

AIM

To assess the push-out bond strength and tubular penetration of resin-based and bioceramic sealers after employing two collagen cross-linking agents, namely, cashew nut shell liquid (CNSL) and epigallocatechin-3-gallate (EGCG) on sodium hypochlorite treated root canal dentin.

MATERIALS AND METHODS

Fifty human permanent mandibular premolars selected were decoronated at CEJ, this was followed by cleaning and shaping protocols, root canals were enlarged up to 20 sizes with 6% taper and were randomly divided into the following 5 groups with 10 samples each based on the cross-linking agent and the sealer: • Group I: Irrigation with saline (control). • Group II: Irrigation with cashew nut shell liquid followed by bioceramic sealer obturation. • Group III: Irrigation with cashew nut shell liquid followed by resin-based sealer obturation. • Group IV: Irrigation with EGCG followed by bioceramic sealer obturation. • Group V: Irrigation with EGCG followed by resin-based sealer obturation. Five specimens in each group were evaluated for push-out bond strength with the universal testing machine while the remaining five specimens in each group were evaluated for depth of sealer penetration by a scanning electron microscope (SEM). The data was recorded, tabulated, and statistically analyzed.

RESULTS

The push-out bond strength was found to be maximum in the apical region in all the five groups followed by the middle third and coronal region. The maximum push-out bond strength was seen in group II followed by groups III and IV, and least in group V. The mean depth of tubular penetration of sealers was found to be effective in the coronal portion followed by the middle third while the apical third region showed the least depth penetration of sealers into the tubules. The maximum penetration of sealers was revealed in group V followed by groups III and IV, and least in group II.

CONCLUSION

Within the limitations of this study, it can be concluded that push-out bond strength was found to the maximum in specimens irrigated with cashew nut shell liquid and obturated with bioceramic sealer. The maximum push-out bond strength was seen in the apical third of all root canals followed by the middle and coronal region. The scanning microscopic analysis revealed maximum mean tubular penetration in the coronal portion followed by the middle third and apical third. A greater penetration was seen in specimens irrigated with EGCG and obturated with hybrid sealer.

CLINICAL SIGNIFICANCE

Selection of sealers plays a pivotal role in the success of endodontic therapy. Leakage-related issues can compromise the bond strength enhancing the bond strength can be achieved through the addition of cross-linking agents.

Retreatment of a C-shaped maxillary second molar: case reports and literature review

The root canal systems of maxillary second molar (MSM) variations are complicated, especially the prevalence of fused roots and consequent merged and C-shaped canals, which represent a clinical challenge because canal configurations can be irregular and unpredictable. The purpose of this article was to present 2 cases with a C-shaped configuration diagnosed during root canal retreatment and perform a literature review of this MSM anatomy. Case 1 reports that two palatal root canals fused into a C-shaped configuration that finally formed an apical foramen, which was classified as Type D. Case 2 reflects the fusion of the distobuccal canal and palatal canal into a C-shaped configuration and the configuration was Type C, which was first reported in a case report. Nonsurgical retreatments were proposed and conducted. Evaluation at a 24-month recall revealed that the two patients were symptom-free, and radiographic examination revealed normal periapical tissue. This report serves to remind clinicians of the complexities of the root canal system and that possible anatomic variation should always be anticipated when formulating an effective root canal treatment plan. The use of CBCT imaging coupled with an operative dental microscope will be helpful in locating and identifying supernumerary canals when a preoperative periapical radiograph shows signs of a fused-rooted MSM.

Comparative Evaluation of Antimicrobial Efficacy of Herbal Formulations of Septilin and Triphala with Conventional 2% Chlorhexidine on Root Canal and Oral Commensal Bacteria using Kirby Bauer Method: An in-vitro Study

Background

Endodontic flareups are always very difficult to treat because of reasons like drug resistance previously sodium hypochlorite and chlorhexidine have been used in the literature but with advancements newer materials like herbal products have been tried for this purpose. Thus, present vitro study was conducted to comparatively evaluate the efficacy of herbal formulations on commensals of oral cavity and root canal.

Materials and Methods

In this in vitro study antimicrobial efficacy of chlorhexidine 2%, Septilin and Triphala wer evaluated with the help of Kirby Bauer test. The microorganisms used were Staphylococcus aureus and Escherichia coli. The samples were placed in standardized wells and were subjected to incubation. Subsequently zones of inhibition were measured with the help of a caliper. One-factor analysis of variance, Tukey's least significant difference post hoc test and Student's independent t-test were performed to find a significant difference (P < 0.05) in the two groups.

Results

For chlorhexidine in S. aureus mean antibacterial efficacy was 11.10 ± 1.25 and in E. coli 10.0 ± 1.33. The value for S. aureus was lesser in Triphala with a value of 10.35 ± 1.63 and in E. coli mean value was 9.05 ± 1.27. For Septilin the mean for S. aureus was 10.40 ± 1.04, and the mean antibacterial efficacy in E. coli was 9.65 ± 1.38.

Conclusion

Septilin and Triphala showed remarkable efficacy concerning zones of inhibition. These herbal formulations have tremendous potential to be used as adjuncts to traditional disinfection modalities though it has scope of further research.

Comparison of EASYDO ACTIVATOR, passive ultrasonic, and needle irrigation techniques on the treatment of apical periodontitis: a study in rats

OBJECTIVES

To evaluate the long-term therapeutic effect of EASYDO ACTIVATOR, passive ultrasonic irrigation, and needle irrigation in experimental apical periodontitis in rats.

MATERIALS AND METHODS

Sprague-Dawley male rats were used to produce periapical lesions. The pulp chambers of the bilaterally first mandibular molars were exposed and left open for 21 days. The rats were divided into four groups according to different irrigation protocols. Seven days after irrigation, the mandibles were removed for micro-CT, histological, and immunohistochemical analysis. Serum levels of tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) were assessed by enzyme-linked immunosorbent assays (ELISA). Statistical data were analyzed by one-way analysis of variance (ANOVA) with LSD tests.

RESULTS

The passive ultrasonic irrigation and EASYDO ACTIVATOR groups had the smallest apical lesions compared to the other groups (P < 0.05), while the needle irrigation group had smaller lesions than the control group (P < 0.05). The EASYDO ACTIVATOR group had less inflammation infiltration compared to the control and needle irrigation groups (P < 0.05). The control and needle irrigation groups had more TNF-α expression compared to the passive ultrasonic irrigation and EASYDO ACTIVATOR groups (P < 0.05). The lowest IL-6 expression was observed in the EASYDO ACTIVATOR group. The EASYDO ACTIVATOR group had the lowest serum level of TNF-α than other groups (P < 0.05). IL-6 expression was significantly lower in the EASYDO ACTIVATOR group in comparison with the control and needle irrigation groups (P < 0.05).

CONCLUSIONS

EASYDO ACTIVATOR can significantly reduce the apical lesions and decrease the inflammatory response around the periapical area.

CLINICAL RELEVANCE

EASYDO ACTIVATOR is recommended for clinical application.

Chlorhexidine gluconate enhances the remineralization effect of high viscosity glass ionomer cement on dentin carious lesions in vitro

Background

To compare the mean mineral density (MMD) and examine the remineralization of carious dentin after cavity disinfection with chlorhexidine gluconate (CHX) and restoration with high viscosity glass ionomer cement (H-GIC) in vitro.

Methods

Selective caries removal to leathery dentin was performed in 40 extracted primary molars. The samples were scanned using micro-computed tomography (micro-CT) to determine the MMD baseline and randomly divided into 4 groups (n = 10): Equia™ group, applied dentin conditioner and restored with H-GIC (Equia Forte™), CHX-Equia™ group, disinfected the cavity with 2% CHX before applying dentin conditioner and restored with H-GIC (Equia Forte™), Ketac™ group, restored with H-GIC (Ketac Universal™) and CHX-Ketac™ group, disinfected the cavity with 2% CHX before restored with H-GIC (Ketac Universal™). The samples underwent micro-CT scanning post-restoration and post-pH-cycling to determine their respective MMDs. One sample from each group was randomly selected to analyze by scanning electron microscopy (SEM).

Results

The MMD gain in the 4 groups post-restoration was significantly different between the Equia™ and CHX-Ketac™ groups (oneway ANOVA with Post hoc (Tukey) test, P = 0.045). There was a significant difference in MMD gain post-restoration between the Equia™ and CHX-Equia™ groups (Independent t-test, P = 0.046). However, the Ketac™ and CHX-Ketac™ group’s MMD were similar. The SEM images revealed that the CHX-Ketac™ group had the smallest dentinal tubule orifices and the thickest intertubular dentin among the groups. However, the CHX-Equia™ group had thicker intertubular dentin than the Equia™ group.

Conclusion

Applying 2% CHX on demineralized dentin enhances the remineralization of the dentin beneath the restoration.

Investigating the Antibacterial Effect of Passive Ultrasonic Irrigation, Photodynamic Therapy and Their Combination on Root Canal Disinfection

Introduction: Enterococcus faecalis is a gram-positive, facultative anaerobic bacterium associated with persistent endodontic infections. Conventional disinfection methods may not completely eradicate the bacteria within the root canal system. Therefore, novel modalities have been suggested to optimize root canal disinfection. The aim of this study was to evaluate and compare the antibacterial effect of photodynamic therapy (PDT), passive ultrasonic irrigation (PUI) and their combination in addition to conventional endodontic irrigation against E. faecalis biofilms in root canals. Methods: Root canals of 50 single-rooted extracted human teeth were prepared and incubated with E. faecalis for 21 days. They were then divided into 4 treatment groups and a control group as follows: (1) NaOCl-Syringe irrigation with 2.5% NaOCl, (2) PUI-Passive ultrasonic irrigation with NaOCl, (3) NaOCl+PDT-Photodynamic therapy following syringe irrigation with NaOCl, (4) PUI+PDT, (5) Control-Syringe irrigation with saline. Colony-forming units were counted and bacterial reduction was calculated for each treatment group. Results: All treatments led to significant reductions in the bacterial load compared to the control group. PUI and PUI+PDT led to the complete elimination of the bacteria from the root canals. NaOCl and NaOCl+PDT treatments reduced the bacteria by 99.9% and 99.5% respectively. NaOCl+PDT was significantly less effective in reducing the bacteria compared to other treatment groups. There were no significant differences between the NaOCl, PUI, and PUI+PDT groups. Conclusion: Passive ultrasonic irrigation with or without the combination of Photodynamic therapy completely eradicated the bacteria. The use of PDT as an adjunction to NaOCl syringe irrigation and PUI did not enhance their antibacterial effect.

An Evaluation of Sporicidal Treatments against Blown Pack Spoilage Associated Clostridium estertheticum and Clostridium gasigenes Spores

Blown pack spoilage (BPS) occurs when meat is cross-contaminated with Clostridium estertheticum or Clostridium gasigenes spores, often from the meat processing environment. This study tested the efficacy of four sporicidal disinfectants commonly used in beef processing plants against C. estertheticum and C. gasigenes spores in a suspension test. D-values were obtained under model ‘clean’ (sterile distilled water, SDW) and ‘dirty’ (3 g/L bovine serum albumin, BSA) conditions. Mean concentration (log10 CFU/mL) were calculated from direct counts. The levels of dipicolinic acid (DPA), indicating damage to the core of these spores, was also monitored using a terbium (Tb)-DPA assay for treatment 1 (peracetic acid as the active ingredient) in SDW and BSA. In SDW sporicidal treatment 3 (containing peroxymonosulphate) was the most effective against C. estertheticum spores but under ‘dirty’ (BSA) conditions sporicidal treatments 1 and 2 were more effective. A similar pattern was obtained with C. gasigenes with treatment 3 being the most effective in SDW but treatment 2 (sodium hypochlorite as the active ingredient) being more effective in BSA. The lower DPA concentrations obtained in SDW versus BSA demonstrated the protective effect of organic matter. It was concluded that meat processors should use a 5% formulation containing sodium hypochlorite, sodium hydroxide and alkylamine oxide to eliminate BPS Clostridial spores in the abattoir.

Investigation of ellagic acid rich-berry extracts directed silver nanoparticles synthesis and their antimicrobial properties with potential mechanisms towards Enterococcus faecalis and Candida albicans

The essential goals of this present study are to elucidate the formation mechanism of ellagic acid rich-blackberry, BBE, (Rubus fruticosus L.) and raspberry, RBE, (Rubus idaeus L.) extracts directed silver nanoparticles and to investigate thier antimicrobial properties towards model dental pathogens E. faecalis and C. albicans compared to BBE, RBE, NaOCl, CHX and EDTA. Both %5 w/w of BBE and RBE reacted with 5 mM Ag ⁺ ions at room temperature (25 °C) under mild-stirring, the formation of BBE and RBE directed b@Ag NP and r@Ag NP was monitored over time by using an Uv-vis spectrophotometer. Both b@Ag and r@Ag NPs were also complementarily characterized with SEM and FT-IR. In terms of the antimicrobial studies, b@Ag NP, r@Ag NP, %5 BBE and RBE, 5 mM AgNO₃, %5 NaOCl, %1,5 CHX and %15 EDTA were separately incubated with E. faecalis and C. albicans suspensions. The results were evaluated with student t-test using GraphPad Prism 8.0.1 statistical software (P < 0.05). While formation of b@Ag NP was confirmed with characteristic absorbance at ~435 nm in 20 min (min) of incubation, r@Ag NP did not give absorbance till 80 min owing to concentration of ellagic acid acted as a reducing and stabilizng agent for formation of the Ag NPs. Intrestingly, 50 ppm r@Ag NP inactivated ∼89% and ∼99% of E. faecalis and C. albicans cell, respectively, ∼25% and ∼40% cell inactivations for E. faecalis and C. albicans were observed respectively with 50 ppm b@Ag NP. We showed that 50 ppm r@Ag NP has effective antimicrobial property as much as mostly used %5 NaOCl and %1,5 CHX solutions.

Efficacy of passive ultrasonic irrigation in the removal of three different intracanal medicaments - An in-vitro study

Background

A successful root canal treatment involves the elimination of microorganisms, and prevents them from reinfecting the root and/or peri-radicular tissues. This can be mainly achieved by efficient cleaning and shaping of the root canal system. Due to the complexity of the root canal morphology, hand and rotary files cannot clean areas such as the isthmuses and lateral canals. In such cases, effective irrigation and the use of intracanal medicaments are essential. Medicaments that are applied should be removed before obturation.

Aim

To evaluate the efficacy of passive ultrasonic irrigation in the removal of three different intracanal medicaments - Triple antibiotic paste (TAP), Odontopaste, and Metapex using a stereomicroscope.

Methodology

A total of 45 single-rooted human teeth were selected and decoronated. The root canals were shaped with ProTaper rotary files. The specimens were fixed in modified Eppendorf vials with silicone material. The roots were split longitudinally, and a standardized groove was prepared in the apical part. The teeth were randomly divided into three groups each containing 15 samples based on the intracanal medicament used: TAP, Odontopaste, and Metapex.

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The root halves were reassembled with sticky wax and remounted in the Eppendorf vial. Each specimen was irrigated with 3% NaOCl and agitated using a passive ultrasonic device. The root segments were disassembled. Digital images were obtained using a stereomicroscope.

Results

The data were evaluated statistically using Kruskal-Wallis and Mann-Whitney U tests. There was a statistically significant difference in the remaining intracanal medicament score (P < 0.05).

Conclusion

Odontopaste showed the least remaining amount score, whereas TAP and Metapex showed greater retention within the dentin.

The effect of intracanal medication variations on microhardness of simulated immature root dentin

The effect of different medicaments and irrigation solutions on root dentin microhardness (MH) was evaluated depending on time. After initial measurements, MH of 60 maxillary incisors (n = 15 per group) was measured after 3 steps: irrigation with 2.5% sodium hypochlorite, exposure to medicaments [triple antibiotic (TAP) or calcium hydroxide (CH) pastes, 1 week or 1 month)] and final irrigation [20 mL of 17% EDTA or 20 mL 1% phytic acid (PA)]. The percentage of MH reduction was calculated. Data were analysed statistically at P < 0.05. Treatments caused a significant decrease in MH values compared to baseline and pre-measurements (P < 0.05). TAP significantly reduced the MH values of the samples over time (P < 0.05). Removal of TAP after 1 month with PA resulted in a significant reduction in MH compared to removing TAP after 1 week and CH removing after 1 month (P < 0.05). Considering the chemical preparation steps, the most hazardous effect on MH was observed after the first irrigation.

Effect of Propolis Nanoparticles against Enterococcus faecalis Biofilm in the Root Canal

To determine the antibacterial effect of propolis nanoparticles (PNs) as an endodontic irrigant against Enterococcus faecalis biofilm inside the endodontic root canal system. Two-hundred-ten extracted human teeth were sectioned to obtain 6 mm of the middle third of the root. The root canal was enlarged to an internal diameter of 0.9 mm. The specimens were inoculated with E. faecalis for 21 days. Following this, specimens were randomly divided into seven groups, with 30 dentinal blocks in each group including: group I-saline; group II-propolis 100 µg/mL; group III-propolis 300 µg/mL; group IV-propolis nanoparticle 100 µg/mL; group V-propolis nanoparticle 300µg/mL; group VI-6% sodium hypochlorite; group VII-2% chlorhexidine. Dentin shavings were collected at 200 and 400 μm depths, and total numbers of CFUs were determined at the end of one, five, and ten minutes. The non-parametric Kruskal-Wallis and Mann-Whitney tests were used to compare the differences in reduction in CFUs between all groups, and probability values of p < 0.05 were set as the reference for statistically significant results. The antibacterial effect of PNs as an endodontic irrigant was also assessed against E. faecalis isolates from patients with failed root canal treatment. Scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) were also performed after exposure to PNs. A Raman spectroscope, equipped with a Leica microscope and lenses with curve-fitting Raman software, was used for analysis. The molecular interactions between bioactive compounds of propolis (Pinocembrin, Kaempferol, and Quercetin) and the proteins Sortase A and β-galactosidase were also understood by computational molecular docking studies. PN300 was significantly more effective in reducing CFUs compared to all other groups (p < 0.05) except 6% NaOCl and 2% CHX (p > 0.05) at all time intervals and both depths. At five minutes, 6% NaOCl and 2% CHX were the most effective in reducing CFUs (p < 0.05). However, no significant difference was found between PN300, 6% NaOCl, and 2% CHX at 10 min (p > 0.05). SEM images also showed the maximum reduction in E. faecalis with PN300, 6% NaOCl, and 2% CHX at five and ten minutes. CLSM images showed the number of dead cells in dentin were highest with PN300 compared to PN100 and saline. There was a reduction in the 484 cm^-1 band and an increase in the 870 cm^-1 band in the PN300 group. The detailed observations of the docking poses of bioactive compounds and their interactions with key residues of the binding site in all the three docking protocols revealed that the interactions were consistent with reasonable docking and IFD docking scores. PN300 was equally as effective as 6% NaOCl and 2% CHX in reducing the E. faecalis biofilms.

Biocompatibility of the 8.25% sodium hypochlorite irrigant solution in endodontics: An in vivo study

The biocompatibility of irrigant solutions, including 8.25% sodium hypochlorite (NaOCl), was analyzed in samples (n = 25) of chorioallantoic membranes (CAM) from embryos of the Gallus gallus, using the hen's egg test on chorioallantoic membrane (HET-CAM). The following irrigants were tested: saline (control), 2% chlorhexidine (2% CHX), and NaOCl (2.5%, 5.25%, and 8.25%), and morphological and microcirculatory changes were investigated. Images were selected and quantified with Image J®. The macroscopic data were submitted to ANOVA, followed by the Tukey's test (p < .05); non-parametric Kruskal-Wallis and Mann-Whitney tests were applied to histological data (p < .05). The frequency of hyperemia differed significantly in the 8.25% NaOCl compared to the other groups, with the exception of 5.25% NaOCl (p = .096). Coagulation was more frequent in the 2% CHX group, differing significantly from the 2.5% NaOCl group (p = .038). In mean values, NaOCl 8.25% caused the decrease (NaOCl = 2.60, and control = 5.00) of vessels in the microcirculation, as well as triggered the increase (NaOCl = 425.50, and control 44.50) of inflammatory cells in the observed areas. There was necrosis in all samples in the 5.25% NaOCl group and in 80% in the 2% CHX, 2.5% NaOCl, and 8.25% NaOCl groups. Fibroblasts were detected only in the control group. It was concluded that the 8.25% NaOCl solution showed significantly high toxicity on CAM. However, these results were comparable to the other concentrations of NaOCl and to 2% CHX. Thus, in this experimental protocol, 8.25% NaOCl proved to be viable as an irrigant solution.

Root canal microorganisms and their antibiotic susceptibility in patients with persistent endodontic infections, with and without clinical symptoms

Secondary/persistent infections are present in teeth with previous root canal treatment, and a great variety of anaerobic microorganisms has been observed in these infections. The antibiotics prescription is occasional; however, in some cases, it is essential, particularly when the general health condition of the patient is compromised. The aims of this study were to identify the associated microorganisms in diagnosis of persistent or secondary apical periodontitis and to evaluate the susceptibility level to the antibiotics most used. Fifteen patients with persistent or secondary apical periodontitis requiring endodontic re-treatment were included. Microbiological samples were taken from the root canals and incubated in thioglycollate under anaerobic conditions. Anaerobic CDC agar (formulated by the Center for Disease Control and Prevention) was employed as a culture medium and the microorganisms were identified using the API system. The microorganisms were subjected to antibiograms with three different antibiotics. Twenty-six microorganisms were identified, the most common genus was Enterococcus (26.8%), Streptococcus (19.22%), Aerococcus (19.1%), and Clostridium (11.4%). 48% of them were susceptible to amoxicillin, with 28% of resistance. For clavulanic acid/amoxicillin, the susceptibility occurred in 32%, with 28% of resistance; and for clindamycin, the susceptibility was present in 40%, with 52% of resistance. The most frequently detected associated microorganism for secondary infections was genus Enterococcus, which exhibited high resistance to the studied antibiotics.

Comparative evaluation of pulp tissue dissolution ability of sodium hypochlorite by various activation techniques: An in vitro study

Background:

The success in endodontic therapy is dependent largely on the absolute elimination of pulp tissue remnants and the maximum reduction of pathologic microbial load present within the root canal system.

Aim:

The aim of this in vitro study was to compare and evaluate the ability of pulp tissue dissolution with and without activation of 5.25% sodium hypochlorite (NaOCl).

Materials and Methods:

Pulp tissue samples collected from intact, noncarious extracted third molars were standardized to 8 mg in each group. These samples were placed in conical Eppendorf tubes of 15 ml with 10 ml 5.25% NaOCl for 4 min and were activated suitably according to the group specifications. All the procedures in this study were carried out at room temperature. The preweighed pulp tissue samples were further weighed again after the dissolution phase, and residual weight loss in each group along with its percentage was obtained. The results were then statistically analyzed using one-way analysis of variance and Tukey post hoc test.

Results:

The maximum amount of pulp tissue dissolution was found in the laser-assisted irrigation group, i.e., NaOCl with Er, Cr: YSGG (P < 0.05) and showed a statistically significant result in comparison with other groups.

Conclusion:

Within the limitations of the study, laser-assisted irrigation with a radial firing tip (NaOCl activated by Er, Cr: YSGG) was the most effective in dissolving the pulp tissue in comparison with other groups. The ultrasonic activation also showed a considerable amount of pulp tissue dissolution comparable to laser-activated irrigation in this study.

Effectiveness of chitosan-propolis nanoparticle against Enterococcus faecalis biofilms in the root canal

Background

The successful outcome of endodontic treatment depends on controlling the intra-radicular microbial biofilm by effective instrumentation and disinfection using various irrigants and intracanal medicaments. Instrumentation alone cannot effectively debride the root canals specially due to the complex morphology of the root canal system. A number of antibiotics and surfactants are being widely used in the treatment of biofilms however, the current trend is towards identification of natural products in disinfection. The aim of the study was to determine the antibacterial effect of chitosan-propolis nanoparticle (CPN) as an intracanal medicament against Enterococcus faecalis biofilm in root canal.

Methods

240 extracted human teeth were sectioned to obtain 6 mm of the middle third of the root. The root canal was enlarged to an internal diameter of 0.9 mm. The specimens were inoculated with E. faecalis for 21 days. Following this, specimens were randomly divided into eight groups (n = 30) according to the intracanal medicament placed: group I: saline, group II: chitosan, group III: propolis100 µg/ml (P100), group IV: propolis 250 µg/ml (P250), group V: chitosan-propolis nanoparticle 100 µg/ml (CPN100), group VI: chitosan-propolis nanoparticle 250 µg/ml (CPN250), group VII: calcium hydroxide(CH) and group VIII: 2% chlorhexidine (CHX) gel. Dentine shavings were collected at 200 and 400 μm depths, and total numbers of CFUs were determined at the end of day one, three and seven. The non-parametric Kruskal Wallis and Mann–Whitney tests were used to compare the differences in reduction of CFUs between all groups and probability values of p < 0.05 were set as the reference for statistically significant results. The scanning electron microscope (SEM) and confocal laser scanning microscopy (CLSM) were also performed after exposure to CPNs. The effectiveness of CPNs were also evaluated against E. faecalis isolated obtained from patients having failed root canal treatment.

Results

The treatments of chitosan, P100, P250, CPN100, CPN250, CH and 2% CHX reduced the CFUs significantly compared to saline (p < .05). On day one and three, at 200 and 400-μm, CPN250 showed significant reduction of CFUs compared to all other groups (p < .05), while CPN100 was significantly better than other groups (p < .05) except CPN250 and 2% CHX. On day seven, at 200-μm CPN250 showed significant reduction of CFUs compared to all other groups (p < .05) except CPN100 and CHX, while at 400 μm CPN250 showed similar effectiveness as CPN100, CH and 2% CHX. SEM images showed root canal dentin treated with CPN250 had less coverage with E. faecalis bacteria similarly, CLSM images also showed higher percentage of dead E. faecalis bacteria with CPN250 than to CPN100.

Conclusion

CPN250 was the most effective in reducing E. faecalis colonies on day one, three at both depths and at day seven CPN250 was equally effective as CPN100 and 2% CHX.

Investigation of an Improved Side-Vented Needle and Corresponding Irrigation Strategy for Root Canal Therapy with CFD Method

BACKGROUND AND OBJECTIVE

This research aimed to present an improved side-vented needle and explore its availability as well as the corresponding irrigation strategy.

METHODS

A CFD model was used to simulate the irrigant flow in a simplified prepared round root canal with an apical delta respectively with different needles for irrigation. The needle types include flat end-tip needle, original side-vented needle, and improved side-vented needle. Different insertion depths and inlet velocities were contrastively studied, as well as the gap size between the bulb at the end tip of the improved side-vented needle and the root canal. The study includes a total of 13 schemes. Velocity, pressure, and shear stress in the root canal were measured to contrast the internal flow-field details and irrigation efficiencies between different schemes.

RESULTS

Poor irrigation replacement appeared in the schemes without enough needle insertion no matter which kind of needle has been used, though relatively lower pressure emerged at the apical foramen. On the contrary, deepening needle insertion not only brings better irrigant replacement but also higher apical foramen pressure. The original side-vented needle tends to make lower pressure at the apical foramen and simultaneously worse irrigant replacement as compared to the flat end-tip needle. The fluid entering the apical anatomy part deceases a lot as the original side-vented needle was replaced by the improved one. The scheme using the improved side-vented needle with gap size ratio and inlet velocity respectively equaling 5.0% and 5.50m/s can be considered the best one.

CONCLUSIONS

The improved side-vented needle can ensure acceptable irrigant replacement performance without leading to a high-pressure level at the apical foramen. The gap between the bulb and the wall of the root canal is very crucial for the pressure at the apical. The ideal irrigation strategy is ensuring the gap equals zero. However, it is a little hard to realize during the whole procedure of the root canal preparation except the final step. Consequently, another strategy that keeping the value of gap size ratio as small as possible such as less than 15% and simultaneously ensuring lower-velocity coming fluid, is necessary in the non-final irrigation.

Current trends in endodontic irrigation amongst general dental practitioners and dental schools within the United Kingdom and Ireland: a cross-sectional survey

Aims To investigate current trends in endodontic irrigation amongst general dental practitioners (GDPs) and dental schools within UK and Ireland. Secondly, to evaluate if significant differences exist between the irrigant practices of National Health Service (NHS) and private GDPs.Methodology In 2019, an online questionnaire was distributed to the 18 dental schools within the UK and Ireland and 8,568 GDPs. These surveys explored current trends in teaching and usage of endodontic irrigants. Chi-squared tests were performed to make comparisons between NHS and private GDPs (α <0.01).Results All 18 dental schools (100%) and 495 GDPs (6%) returned valid questionnaires. Three hundred and thirty (66.7%) practitioners were NHS and 165 (33.3%) were private. There was strong consensus on irrigation teaching amongst dental schools. These results aligned with GDP responses in terms of irrigant selection (sodium hypochlorite [NaOCl]); NaOCl concentration (≤3%); ethylenediaminetetraacetic acid (EDTA) contact time (>0-5 minutes); final rinse protocols (penultimate EDTA rinse); irrigant temperature (room); and agitation techniques (manual dynamic activation; >0-60 seconds). There was, however, considerable variation in NaOCl contact time and GDPs infrequently used chelating agents or agitation techniques. Compared with private practitioners, NHS GDPs used significantly lower NaOCl contact times and concentrations, less EDTA and activation techniques, and more chlorhexidine (P <0.01).Conclusions Overall, irrigation teaching within the UK and Ireland is consistent and evidence-based. Furthermore, trends in irrigant usage amongst UK GDPs are now more aligned with these teaching practices. Significant differences were, however, observed between NHS and private practitioners.

The Combination of Diode Laser and Ozonated Water in the Treatment of Complicated Pulp Gangrene

The study aimed to investigate the effects of endodontic space decontamination using a laser combined with ozonated water in the therapy of complicated pulp gangrene. The subject of this in vivo study was a 12-year-old patient diagnosed with extensive periapical periodontitis on the mandibular right first molar. Biological samples were initially collected to identify the active pathogen—Enterococcus faecalis, then the nonsurgical endodontic treatment was performed in a single visit, according to the active disinfection guidelines of the identified pathogen. Two-month postoperative, clinical and radiological examination revealed a complete healing of the periapical lesion. The correct diagnosis of this endodontic–periodontal pathology, and the unconventional treatment of the complex system of infected root canals, allowed a favorable treatment result without any surgical intervention. This unconventional approach, which combines a laser technique with ozonated water, allows for predictable results in periapical lesion treatment.

Human pulp tissue dissolution ability of different extracts of Sapindus mukorossi: An in vitro study

Objective

Due to the many negative properties of sodium hypochlorite used in current root canal treatment, interest in biocompatible natural agents is increasing day by day. The aim of this study was to evaluate whether various extract solutions of Sapindus mukorossi have dissolution effects on human pulp tissues.

Methods

Primarily powder extracts were obtained by extracting fruit shells of S. mukorossi in different solvents (ethanol, methanol, buthanol and distilled water). The test solutions were prepared and randomly separated into six groups with 10 samples in each group: ethanol extract, methanol extract, butanol extract, distilled water extract of S. mukorossi, sodium hypochlorite (NaOCl) and the control group. Among these, S. mukorossi extracts were separated into two subgroups, depending on their concentration level (50 µg/mL and 100 µg/mL). The pulp tissues of freshly extracted human molars were used for dissolution test. The weights of the pulpal tissues were measured and recorded for two times after the samples were placed in the solutions. Statistical analysis for all descriptive statistics was performed using SPSS 22 (P < 0.05).

Results

Our results showed that maximum percent yield of preparation was obtained in methanol extract of S. mukorossi. Among all of the groups, the best dissolution capacity was seen in the NaOCl group (positive control group). Among S. mukorossi groups, the best tissue solvent solution was found in SMM group at 50 µg/mL and SMB group at 100 µg/mL.

Conclusion

The different extracts of S. mukorossi had a capacity to dissolve pulp tissue but this capacity was less than NaOCl. Therefore, further studies will enable the creation of a commercial solution for clinical use by increasing the effectiveness of S. mukorossi while combining it with other endodontic irrigation solutions.

Antibacterial Activity and Impact of Different Antiseptics on Biofilm-Contaminated Implant Surfaces

Several antiseptic agents have been proposed for the treatment of peri-implantitis as a complementary therapeutic strategy in addition to mechanical devices. The aim of this study was to compare six different antiseptics, as well as alternative formulations of the same chemical agent, with respect to their decontamination efficacy and impact on chemical properties of the implant surface. Titanium disks with a micro-rough surface, previously contaminated with Porphyromonas gingivalis and Streptococcus mutans biofilms, were treated for 2 min with different antiseptics (liquid sodium hypochlorite 5.25%, gel sodium hypochlorite 5.25%, liquid chlorhexidine 0.2%, gel chlorhexidine 1%, gel citric acid 40%, and gel orthophosphoric acid 37%) or sterile saline solution (control) and their antibacterial activity as well as their ability to remove biofilm were assessed by viable bacterial count and scanning electron microscopy, respectively. Spectroscopic analysis was also performed on non-contaminated disks after exposure to the antiseptics, in order to detect any change in the elemental composition of the titanium surface. All the antimicrobial formulations examined were effective against P. gingivalis and S. mutans biofilms. SEM analysis revealed however that liquid sodium hypochlorite 5.25% was more effective in dissolving biofilm residues. Spectroscopic analysis detected traces of the antiseptics, probably due to insufficient rinsing of the titanium surfaces. In conclusion, since gel formulations of these antiseptic agents possessed a similar antibacterial activity to the liquid formulations, these may be proposed as alternative treatments given their properties to avoid overflows and increase contact time without significant side effects on the bone.