Antibacterial efficacy of copper-added chitosan nanoparticles: a confocal laser scanning microscopy analysis.

The aim of this study was to evaluate the antibacterial efficacy of copper added chitosan nanoparticles (CU-CNPs) as an irrigation solution with different irrigants in terms of eliminating Enterococcus Faecalis (E. faecalis) from the root canals. Fifty mandibular premolar teeth were prepared and infected with E. faecalis for 21 days. After the incubation period, samples were randomly divided into a control group irrigated with distilled water and 4 experimental groups (n = 10) irrigated with as follows, %6 NaOCl, %6 NaOCl + %9 editronate (HEBP), Chitosan nanoparticles (CNPs), and CU-CNPs. To calculate the proportion of dead E. faecalis cell volume, stained using LIVE/DEAD BacLight Bacterial Viability Kit and were scanned using confocal laser scanning microscope (CLSM). All the irrigation solutions significantly (P < .05) killed the bacteria in the canal, except for the control group. CU-CNPs solution killed the highest (P < .05) number of bacteria compared with the other experimental groups. No significant difference was found between CNPs, NaOCl + HEBP, and NaOCl in terms of antibacterial activity. CU-CNPs solution was exhibited higher antibacterial efficacy against E. faecalis.

Evaluation of smear layer and debris removal by stepwise intraoperative activation (SIA) of sodium hypochlorite.

OBJECTIVES: To evaluate the efficacy of a stepwise intraoperative activation (SIA) of irrigants during and after the instrumentation compared with that of a conventional activation (CA) performed only after the instrumentation to remove smear layer and debris using different activation devices. MATERIALS AND METHODS: A total of 70 single-rooted teeth were divided into a control group (no activation, n = 10) and two different experimental groups according to the irrigant activation protocol used: group 1 (CA), in which sodium hypochlorite was activated only after the use of the last mechanical file, and group 2 (SIA), in which activation was performed during and after the instrumentation. The two groups were divided into 3 subgroups according to the activation device used (n = 10): passive ultrasonic irrigation (PUI, subgroup a), EndoActivator (EA, subgroup b), and EDDY (subgroup c). The roots were split longitudinally and observed using scanning electron microscopy (SEM) to evaluate the presence of debris and smear layer, and the results were statistically analyzed. RESULTS: All activation protocols and devices were more effective than control group in removing smear layer and debris from all root canal thirds (P < 0.05), except for CA-EA (group 1b) in the apical third. In the apical third, SIA was found to be more effective than CA (P < 0.05) to remove smear layer and residual debris when PUI was used, to remove the smear layer when EA was used (P < 0.05), and to remove residual debris when EDDY was used (P < 0.05). PUI and EDDY removed statistically more smear layer and debris than EA in the apical third (P < 0.05). CONCLUSIONS: The SIA technique improved the smear layer and debris removal from the apical third and debris removal from the coronal third, and PUI and EDDY were more effective than EA in the apical third. CLINICAL RELEVANCE: The stepwise intraoperative activation (SIA) technique may increase smear layer and debris removal.

Evaluation of artificial intelligence for detecting periapical pathosis on cone-beam computed tomography scans.

AIM: To verify the diagnostic performance of an artificial intelligence system based on the deep convolutional neural network method to detect periapical pathosis on cone-beam computed tomography (CBCT) images. METHODOLOGY: images of 153 periapical lesions obtained from 109 patients were included. The specific area of the jaw and teeth associated with the periapical lesions were then determined by a human observer. Lesion volumes were calculated using the manual segmentation methods using Fujifilm-Synapse 3D software (Fujifilm Medical Systems, Tokyo, Japan). The neural network was then used to determine (i) whether the lesion could be detected; (ii) if the lesion was detected, where it was localized (maxilla, mandible or specific tooth); and (iii) lesion volume. Manual segmentation and artificial intelligence (AI) (Diagnocat Inc., San Francisco, CA, USA) methods were compared using Wilcoxon signed rank test and Bland-Altman analysis. RESULTS: The deep convolutional neural network system was successful in detecting teeth and numbering specific teeth. Only one tooth was incorrectly identified. The AI system was able to detect 142 of a total of 153 periapical lesions. The reliability of correctly detecting a periapical lesion was 92.8%. The deep convolutional neural network volumetric measurements of the lesions were similar to those with manual segmentation. There was no significant difference between the two measurement methods (P > 0.05). CONCLUSIONS: Volume measurements performed by humans and by AI systems were comparable to each other. AI systems based on deep learning methods can be useful for detecting periapical pathosis on CBCT images for clinical application.

Influence of size and taper of basic root canal preparation on root canal cleanliness: a scanning electron microscopy study.

AIM: To investigate whether a minimally invasive basic root canal preparation technique has an influence on root canal cleanliness in extracted mandibular molar teeth. METHODOLOGY: A total of 80 root canals (40 mesio-buccal and 40 mesio-lingual) from 40 mandibular molars were included. The teeth were divided equally into four different experimental groups depending on the subsequently root canal preparation technique: Group 1: a basic preparation was performed up to size 20, .04 taper; Group 2: a basic preparation was performed up to size 2, .06 taper; Group 3: a basic preparation was performed up to size 25, .04 taper; and Group 4: a basic preparation was performed up to size 25, .06 taper. After the use of each instrument, each root canal was irrigated with 2.5 mL of 6% sodium hypochlorite for 30 s. Then, 1 mL NaOCl was activated for 20 s using an EDDY sonic tip. Final irrigation was performed using a total of 5 mL of 17% EDTA solution. The roots were then split longitudinally and all root canal thirds were observed through scanning electron microscopy (SEM) to evaluate the presence of superficial debris and smear layer using a scoring system. Data were statistically analysed using the Kruskal-Wallis and Bonferroni tests with a level of significance set at P < 0.05. RESULTS: In all groups, there was significantly more residual debris and smear layer in the apical third (P < 0.05), with no differences between the middle and coronal thirds (P > 0.05). For both the parameters analysed, there was no difference amongst the groups in the middle and coronal thirds (P > 0.05), whilst in the apical third significantly less debris and smear layer was found in specimens from groups 3 and 4 than for groups 1 and 2 (P < 0.05). CONCLUSION: All basic root canal preparation techniques were associated with less debris and smear layer on the canal walls in the middle and coronal thirds, without differences among them. Even though debris and smear layer were always present in the apical third, an apical size of 25 resulted in significantly cleaner canals walls compared to a size 20.

Buccal infiltration versus inferior alveolar nerve block in mandibular 2nd premolars with irreversible pulpitis.

PURPOSE: The purpose of this study is to compare the success rates of inferior alveolar nerve block (IANB) and buccal infiltration anesthesia of mandibular second premolar with irreversible pulpitis and to evaluate the level of patient discomfort with these methods. MATHERIALS AND METHODS: Forty patients, who had irreversible pulpitis in the mandibular 2nd premolar teeth, were included in the study. Patients were randomly distributed in two groups. In one group IANB, in the other group buccal infiltration anesthesia were performed. The efficacy of these two different anesthesia techniques on the related teeth was investigated with the Heft-Parker visual analog scale. In addition, with a pulse oximetry device, the changes in the patients' heart rates were compared between the groups. The obtained data were evaluated statistically. RESULTS: Both anesthesia techniques reduced the pain significantly in patients before the administration (P < 0.05), but there was no significant difference among the groups regarding the pain control and success rates of anesthesia (P > 0.05). Both of the anesthesia techniques increased the heart rate (P < 0.05). The increase in the heart rate of the patients was significantly higher in the buccal infiltration anesthesia group than the other anesthesia group (P < 0.05). CONCLUSION: Within the limitation of this in vivo study, there was no difference between the efficacies of the buccal infiltration anesthesia and IANB anesthesia in the mandibular 2nd premolar teeth with irreversible pulpitis. Buccal infiltration anesthesia caused more discomfort in the patients compared with the IANB during the administration.

Effect of multiple autoclave cycles on the surface roughness of HyFlex CM and HyFlex EDM files: an atomic force microscopy study.

AIM: To compare the effect of autoclave cycles on the surface topography and roughness of HyFlex CM and HyFlex EDM instruments using atomic force microscopy (AFM) analysis. METHODOLOGY: Eight new files of each brand were subdivided into four subgroups (n = 2/each subgroup). One group was allocated as the control group and not subjected to autoclave sterilization. The other three groups were subjected to different numbers (1, 5, and 10) of autoclave sterilization cycles. After the cycle instruments were subjected to AFM analysis. Roughness average (Ra) and the root mean square (RMS) values were chosen to investigate the surface features of endodontic files. The data was analyzed using one-way ANOVA and post hoc Tamhane tests at 5% significant level. RESULTS: The lowest Ra and RMS values were observed in the HyFlex EDM files that served as the control and in those subjected to a single cycle of autoclave sterilization (P < 0.05). The highest Ra and RMS values were observed in the HyFlex CM and HyFlex EDM files that were subjected to 10 cycles of autoclave sterilization (P < 0.05). The surface roughness values of the HyFlex CM group showed a significant increase after ten autoclave cycles, whereas those of the HyFlex EDM group exhibited a significant change after five autoclave cycles (P < 0.05). CONCLUSIONS: Although the initial surface roughness values of the HyFlex EDM files were lower than those of the HyFlex CM files, the surface roughness values of the EDM files showed a statistically significant increase after 5 cycles of autoclave sterilization. In contrast, the surface roughness values of the HyFlex CM files did not increase until 10 cycles of autoclave sterilization. CLINICAL RELEVANCE: Present study indicated that autoclave sterilization negatively affected the surface roughness of the tested NiTi files.

Comparison of cyclic fatigue resistance and bending properties of two reciprocating nickel-titanium glide path files.

AIM: To compare the cyclic fatigue resistance and bending properties of R-Pilot and WaveOne Gold (WOG) Glider files, at intracanal temperature (35°C). METHODOLOGY: Forty R-Pilot and 40 WOG Glider files were subjected to a cyclic fatigue resistance test (n = 20), calculating the time to fracture (TTF) in an artificial stainless steel canal. The length of the fractured file tips (FL) was also measured. The fracture surface of fragments was examined with a scanning electron microscope, and the cross-sectional area of the fractured surfaces was measured. Flexibility of the tested files (n = 20) was determined using 45° bending test. Data were analysed statistically using the Mann-Whitney U-test at 5% significance level. RESULTS: Time to fracture was significantly higher in the R-Pilot group compared to the WOG Glider (P < 0.05). There was no significant difference between groups for fracture length. The bending resistance of R-Pilot files was significantly greater than WOG Glider files (P < 0.05). CONCLUSIONS: A significant greater cyclic fatigue resistance was observed for R-Pilot files compared to WOG Glider instruments, although the bending resistance of WOG Glider files was lower.

Cyclic fatigue resistances of several nickel-titanium glide path rotary and reciprocating instruments at body temperature.

AIM: To compare the cyclic fatigue resistance of the One G, ProGlider, HyFlex EDM and R-Pilot glide path NiTi files at body temperature. METHODOLOGY: Twenty One G (size 14, .03 taper), 20 ProGlider (size 16, .02 taper), 20 HyFlex EDM (size 10, .05 taper) and 20 R-Pilot (size 12.5, .04 taper) instruments were operated in rotation at 300 rpm (One G, ProGlider and HyFlex) or in reciprocation (R-Pilot) at 35 °C in artificial canals that were manufactured by reproducing the size and taper of the instrument until fracture occurred. The time to fracture was recorded in seconds using a digital chronometer, and the length of the fractured fragments was registered. Mean data were analysed statistically using the Kruskal-Wallis test and post hoc Tukey tests via SPSS 21.0 software. The statistical significance level was set at 5%. RESULTS: The cyclic fatigue resistance of the R-Pilot files was significantly greater than the other instruments, and the One G was significantly lower (P < 0.05). There was no difference between the HyFlex EDM and the ProGlider (P > 0.05). No significant difference (P > 0.05) was evident in the mean length of the fractured fragments of the various instruments. CONCLUSIONS: The cyclic fatigue resistance of the R-Pilot reciprocating glide path file was significantly greater than that of the rotary HyFlex EDM, ProGlider and One G glide path files.

Cyclic fatigue resistance of R-Pilot, HyFlex EDM and PathFile nickel-titanium glide path files in artificial canals with double (S-shaped) curvature.

AIM: To examine the cyclic fatigue resistances of R-Pilot, HyFlex EDM and PathFile NiTi glide path files in S-shaped artificial canals. METHODOLOGY: Twenty R-Pilot (12.5/.04), 20 HyFlex EDM (10/.05) and 20 PathFile (19/.02) single-file glide path files were included. Sixty files (n: 20/each) were subjected to static cyclic fatigue testing using double-curved canals until fracture occurred (TF). The number of cycles to fracture (NCF) was calculated by multiplying the rpm value by the TF. The length of the fractured fragment (FL) was determined by a digital microcaliper. Six samples of fractured files (n: 2/each) were examined by SEM to determine the fracture mode. The NCF and the FL data were analysed using one-way anova, post hoc Tamhane and Kruskal-Wallis tests using SPPS 21 software. The significance level was set at 5%. RESULTS: In the double-curved canal, all the files fractured first in the apical curvature and then in the coronal curvature. The NCF values revealed that the R-Pilot had the greatest cyclic fatigue resistance, followed by the HyFlex EDM and PathFile in both the apical and coronal curvatures (P < 0.05). CONCLUSIONS: R-Pilot NiTi glide path files, used in a reciprocating motion, had the greatest cyclic fatigue resistance amongst the tested NiTi glide path files in an artificial S-shaped canal.

Apical extrusion of debris using reciprocating files and rotary instrumentation systems.

BACKGROUND: To compare the preparation time and amount of apically extruded debris after the preparation of root canals in extracted human teeth using the reciprocating files and rotary nickel-titanium systems. PROCEDURE: Sixty extracted human mandibular premolars were used. The root canals were instrumented using reciprocating (WaveOne, Reciproc, SafeSider) or rotary motion (Typhoon, ProTaper Universal, Mtwo), and the debris produced was collected in glass vials. The remaining debris was assessed using a microbalance and statistically analyzed using the one-way ANOVA and Duncan multiple range tests at a significance level of P < 0.05. The time required to prepare the canals with different instruments was also recorded. RESULTS: The Reciproc group produced significantly less debris when compared to the Typhoon group (P < 0.05), and instrumentation with the single-file systems was significantly faster than in the multi-file systems (P < 0.05). The WaveOne group extruded significantly more debris per unit of time than the other groups, with the exception of the Typhoon group (P < 0.05). CONCLUSION: According to our study, all systems caused apical debris extrusion. However, the Reciproc group was associated with less debris extrusion when compared to the other groups.