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Purpose To evaluate the effect of different root canal irrigating regimens on the push-out bond strength of RealSeal root canal obturation system. Materials and methods 16 mm ± 1 of roots of 70 freshly extracted single rooted human teeth were obtained and divided randomly into seven groups (n = 10) according to irrigation regimens throughout root canal preparation and final rinse: 1(DW–DW), 2(NaOCl–NaOCl), 3(NaOCl–MTAD), 4(NaOCl–EDTA), 5(CHX–CHX), 6(CHX–MTAD), 7(CHX–EDTA). All root canals of all groups were prepared using K3 root canal preparation system up to size #40/0.06 taper and filled using RealSeal Root canal obturation system. Two-millimeter thick horizontal sections from the coronal, middle and apical thirds of each root were sliced for the push-out bond strength measurement. Results In cervical sections the highest push-out bond strength value was recorded for NaOCl–MTAD (4.074 ± 2.524) followed by CHX–MTAD (3.795 ± 1.935), CHX–EDTA (2.659 ± 0.587), NaOCl–EDTA (2.404 ± 1.166), CHX–CHX (1.905 ± 0.573), NaOCl–NaOCl (1.690 ± 0.427) and the least value was recorded for DW–DW (0.791 ± 0.381) with statistical significant difference between groups (P Conclusion Whenever root canal obturation using RealSeal is decided, it is preferred to use NaOCl solution throughout instrumentation in association with MTAD as a final irrigant after instrumentation to obtain a the highest push-out bond strength to root canal dentin specially at the coronal sections that showed higher bond strength than middle and apical sections.

Aim To evaluate and compare push-out bond strength of four obturation systems; Gutta-percha/AH Plus, GuttaFlow, RealSeal and EndoREZ system to root canal dentin. Materials and methods Human freshly extracted 80 mandibular premolars were prepared and assigned to experimental groups (n = 20), designated as Group I: Gutta-percha/AH Plus, Group II: GuttaFlow system, Group III: RealSeal points/RealSeal Self-etch and EndoREZ obturation system. After obturation, each tooth was prepared for push-out assessment with root slices of 2 mm thickness using universal testing machine. Data were analyzed using one way ANOVA in a level of confident at 95%. Results Gutta-percha/AH Plus root fillings showed significantly highest bond strength. Whereas root segment location did not have a significant influence on bond strength except with Group III. Conclusion The adhesiveness quality to root dentin promoted by newer methacrylate resin-based obturation systems like RealSeal and EndoREZ systems is compromised even when teeth with simple anatomic features were obturated under well-monitored laboratory conditions.

Aim The aim was to clinically evaluate the microbial reduction after using different irrigation–activation techniques including needle irrigation, passive ultrasonic irrigation (PUI) and EndoVac. Materials and Methods Twenty-four patients with single rooted, single-canal teeth with primary endodontic infection were selected for this study then randomly assigned into three groups according to the final irrigation–activation method. Group 1 (control group) needle irrigation, group 2 (PUI irrigation) and group 3 (EndoVac irrigation). The first microbial sample (S1) was taken after access cavity preparation under complete aseptic condition then the second microbial sample (S2) after chemomechanical preparation using ProTaper Universal rotary system up to F3 or F4 or F5 according to canal size. Finally, the third microbial sample (S3) was taken after irrigation–activation, the three samples were cultured on blood agar aerobic and anaerobic, incubated for 24–48 h at 37°C, the growing colonies were counted and recorded as colony forming units. Results PUI group showed the highest microbial reduction, while the needle group showed the lowest microbial reduction with statistically significant difference with both PUI group and EndoVac group. While no statistically significant difference was recorded between PUI and EndoVac groups. Conclusion Irrigation–activation increases the efficacy of irrigation concerning the microbial reduction and PUI is the most recommended method of activation.

Aim The aim was to clinically and radiographically evaluate mineral trioxide aggregate (MTA) and TheraCal LC as direct pulp capping (DPC) materials. Materials and methods Twenty male patients aged 17–35 years with immediate mechanical pulp exposure in lower molars were randomly divided into two equal groups (n = 10). Group 1: pulp exposures were capped using MTA. Group 2: pulp exposures were capped using TheraCal LC. Immediately after DPC, a base-line digital bitewing and periapical radiographs were taken. Clinical evaluation was performed at 1, 4, 12, and 24 weeks after DPC for presence/absence of spontaneous pain, tenderness to percussion, draining sinuses and pulp response to thermal pulp vitality test. At 24 weeks after DPC, digital periapical, and bitewing radiographs were taken. Digitalized bitewing radiographs were submitted to image analysis software to measure dentin bridge thickness in comparison to the base-line bitewing radiographic image. Digitalized preoperative and postoperative periapical radiographs were submitted to the same software to evaluate changes in the width of periodontal ligament space. Results Clinically, all cases showed criteria of successful treatment except 3, four cases in groups 1 and 2, respectively. Statistical analysis revealed no statistically significant difference between both groups (P > 0.05). All of the thirteen cases that were available for evaluation after 6 months showed dentin bridge formation. In MTA group, the mean value of dentin bridge formed was higher than in TheraCal LC group with no statistically significant difference (P = 0.710). Changes in the width of periodontal ligament space were not significantly different between both groups recording (P > 0.05). Conclusion Clinically and radiographically, MTA and TheraCal LC are favorable materials for DPC inducing adequate dentin bridge formation and minimal widening of periodontal ligament space.

Objective To compare smear layer removal after root canal final irrigation with 17% Ethylenediaminetetraacetic acid (EDTA), 10% citric acid (CA), Biopure MTAD, and 0.2% chitosan solutions. Materials and methods Fifty extracted maxillary central incisors were decoronated to a root length of 16 mm. They were cleaned and shaped using ProTaper system up to size F4 and 2.5% sodium hypochlorite (NaOCl) irrigation throughout instrumentation. The specimens were divided into 5 equal groups according to the final irrigation solution; group I: 17% EDTA, group II: 10% CA, group III: MTAD, group IV: 0.2% chitosan, group V (control): 2.5% NaOCl. Samples were split longitudinally and examined under scanning electron microscope for smear layer presence at coronal, middle and apical root canal levels. Results 0.2% chitosan solution has the lowest mean rank of smear layer scores at all tested root sections. The efficacy of MTAD in smear layer removal was better than that of 17% EDTA and 10% CA at the apical level. Coronal sections recorded the lowest mean ranks of smear layer score and the highest was found at the apical section. Conclusion Final irrigation with 0.2% chitosan solution was more efficient in smear layer removal. 17% EDTA, 10% CA, MTAD and 0.2% chitosan effectively but not completely remove the smear layer especially at the apical root levels.

PurposeTo evaluate effect of water storage on micro-shear bond strength of adhesives to class I cavity-bottom dentin using two types of composites resin.Materials and methodsNinety teeth were divided into three groups I,II&III (thirty molars each) according to the adhesive used, either total-etch 2-step (Adper Single Bond, 3M ESPE), self-etch 2-step(Clearfil SE Bond, Kuraray), or self-etch 1-step(Futura Bond, Voco) respectively. Each group was subdivided according to type of composite restoration used, either Hybrid (Clearfil APX, Kuraray), and Packable (Filtek P60, 3M ESPE). All teeth were thermocycled for 500 cycles,and subjected to occlusal load cycling for 120.000 cycles corresponding to 6 months clinical use. Bonding effectiveness was assessed by micro-shear bond strength test (μSBS) after 1 day, 3 months, and 6 months water storage.ResultsThe mean μSBS values (±SD) for Subgroup IA(SB2-APX) were 32.58 ± 1.416, 31.820 ± 2.119, and 30.910 ± 1.393 MPa after 24 h, 3 month, and 6 month respectively; while for Subgroup I B(SB2-P60) were 31.960 ± 1.659, 31.350 ± 1.765, and 30.380 ± 1.773 MPa respectively. Subgroup II A (CSE-APX) recorded 37.28 ± 1.061, 36.77 ± 2.32, 36.21 ± 1.964 MPa, while Subgroup II B(CSE-P60) recorded 37.0 ± 2.115, 36.460 ± 1.727, and 36.080 ± 1.910 MPa after 24 h, 3 month, and 6 month respectively. Subgroup III A (FB-APX) showed 30.550 ± 2.088, 26.890 ± 1.533, and 21.590 ± 1.784 MPa, while subgroup III B (FB-P60) showed 29.790 ± 1.172, 25.960 ± 2.672, and 21.410 ± 2.126 MPa after 24 h, 3 month, and 6 month respectively.ConclusionTwo-step Total-etch and Two-step self etch adhesives showed better tolerance to water storage compared to One-step self-etch adhesive. However, the type of composite restoration had no significant effect on the microshear bond strength of dental adhesives.

Aim To evaluate centering ability, amount of removed dentin of hand NiTi Flex K-files, ProTaper Universal system, OneShape, and WaveOne system in curved root canals. Materials and methods Forty extracted human premolars with a range of canal curvature (21–39°) were used. Samples were randomly divided into four groups (n = 10). Group 1: NiTi Flex (control group), group 2: ProTaper, group 3: OneShape, and group 4: WaveOne Primary. Centering ability of each instrument was evaluated using superimposed standardized preinstrumentation and postinstrumentation cone-beam computed tomography images recorded at three root canal levels (3, 6, and 9 mm from the apex). Amount of removed dentin was calculated by differences between preinstrumentation and postinstrumentation root canal volumes. Results WaveOne system showed the highest mean centering ratios at all tested canal levels in both directions. Apical thirds of all groups showed the highest centering ratios while the coronal showed the lowest. ProTaper system group recorded significantly highest amount of root dentin removal compared to other groups. Conclusion Reciprocating WaveOne files had more centering ability than other tested instruments. ProTaper Universal system removed significantly high amount of dentin in comparison to other systems.

Aim: To assess the effect of dentin powder (DB) and human serum albumin (HSA) as tissue inhibitors on the antibacterial activity of chitosan nanoparticles (CSnps) and chlorhexidine (CHX). Materials and methods: The antibacterial effect of CSnps and CHX in presence or absence of inhibitors was tested on planktonic Enterococcus faecalis OG1RF standard strain. Study groups were group 1: DB and CSnps, group 2: DB and CHX, group 3: HSA and CSnps, and group 4: HSA and CHX, group 5: CSnps suspension (positive control for groups 1, 3), group 6: CHX solution (positive control for groups 2, 4), and bacteria suspension as a negative control (group 7). The assigned medications were added to tissue inhibitors for an hour before bacterial suspension addition. After 1 min, 24, and 72 h of bacterial suspension addition a sample was taken. Bacterial culturing was done on brain heart infusion plates at 37°C. The plates were incubated for 24 h and were inspected for growth by naked eye and the colonies the number of surviving bacteria was calculated. Data were collected and the mean and SD of log10 colony forming units was calculated and statistically analyzed using one-way analysis of variance and pairwise comparison between groups was performed whenever significant difference was found. Level of significance was set at P value less than or equal to 0.05. Results: Group 3and group 7 were statistically significant than all tested groups at all times. Also, significant difference between group 4 versus group 2 and group 6 recording P value of 0.048 at 1 min. However, there was no significant difference between groups 1, 2, 4, 5, 6 at 24 and 72 h. Conclusions: HSA had significant inhibitory effect on antibacterial activity of CHX and CSnps than DB at 1 min. At 24 and 72 h, neither HSA nor DB had significant inhibitory effect on antibacterial activity of CHX while HSA had a significant effect on antibacterial activity of CSnps.

Purpose To evaluate centering ability and canal transportation in curved root canals after using different nickel–titanium (Ni-Ti) preparation systems including two rotary systems [Revo-S and Twisted File (TF)] and hand Ni-Ti-Flex K-files using cone-beam computed tomography. Materials and methods Seventy-five extracted human premolars with similar range of canal curvature (25–35°) were used, after crown removal and working length determination, samples were randomly divided into three groups (n = 25) according to the type of instruments used. Group I (Revo-S), group II (TF) and group III (Ni-Ti-Flex). Preinstrumentation and postinstrumentation cone-beam computed tomography images were recorded at several root canal levels (3, 5, 7, 9, and 11 mm) from the apex under the same circumstances, superimposed and then the centering ability and canal transportation were calculated using specific equations. Results Revo-S system produced less mean value of canal transportation and more centering ability than TF and Ni-Ti-Flex systems. In addition, the middle canal level (7 mm) recorded the least mean value of transportation with the highest centering ability for all used instruments. Conclusion Preparation of curved root canal using rotary systems produced less change in original canal path compared with the hand Ni-Ti files.

Purpose: To evaluate the remaining filling material (gutta-percha/EndoSequence bioceramic sealer) on root canal walls after retreatment using ProTaper universal retreatment (PTUR) system with and without chloroform solvent. Materials and methods: Thirty extracted human premolars with type I root canal system were used. After crown removal and working length determination, all root canals were prepared using nickel–titanium rotary ProTaper system and obturated using gutta-percha as a core filling material with EndoSequence bioceramic sealer. All roots were randomly divided into two equal main groups (n = 15) according to retreatment technique. Group I: filling materials was removed using PTUR system and chloroform as a solvent; while group II: filling materials was removed using PTUR system without solvent. Both groups were cleaved longitudinally and examined under scanning electron microscope to evaluate root canal filling remnants. Results: PTUR system with the aid of chloroform recorded highest values of score percentage of remaining filling material at all tested root canal levels. The values of score percentage of remaining filling materials were significantly lower at coronal level compared to other tested levels. Conclusion: Using chloroform during removal of root canal filling material using rotary instruments was associated with larger amount of residual root canal filling material compared to using rotary instruments only.

Introduction The aim of this study is to compare the debridement efficacy of the EndoVac irrigation system versus needle irrigation with different irrigant solutions using scanning electron microscope. Materials and methods Eighty human freshly extracted single rooted teeth with fully developed, single root canals were collected. The teeth were divided randomly into two equal main groups according to the method of irrigation system used: group A, EndoVac system; and group B, needle irrigation. Each group was further subdivided into four equal subgroups according to the type of irrigant solution used: subgroup 1; sodium hypochlorite (NaOCl), subgroup 2; EDTA, subgroup 3; mixture of tetracycline, acid and detergent (MTAD), subgroup 4; saline. The canals were instrumented to a master apical file size #40/0.02 taper. Roots were split longitudinally in a buccolingual direction and examined under scanning electron microscope. Result At all tested root canal levels, group A recorded lower mean rank of score percentage compared to group B with statistical significant difference between them (P = 0.001 and 0.039 at the middle and the apical root level, respectively), while there was no statistical significant difference between both groups (P = 0.053) at the coronal root level. Conclusion The debridement efficacy of NaOCl only, NaOCl+EDTA, NaOCl+MTAD or even saline increased when using EndoVac system rather than conventional needles especially in the apical third.

Aim To evaluate sealing ability and quality of obturation when canal filled with gutta-percha and either mineral trioxide aggregate (MTA), or AH Plus sealer with detection of any possible correlation between microleakage and voids. Materials and methods Human freshly extracted 30 maxillary one-rooted teeth were prepared and assigned to experimental groups (n = 10), designated as group I: gutta-percha/AH Plus, group II: gutta-percha/MTA sealer, group III positive control group (n = 5) teeth unobturated, group IV: negative control group (n = 5) teeth obturated with gutta-percha, AH Plus sealer. After obturation, each tooth was prepared for fluid filtration assessment. Voids detection was performed through cross-sectional analysis at three root levels. Data were analyzed using one-way analysis of variance at a level of confidence of 95%. Results None of the tested obturation systems was able to provide leak proof filling. The sealing ability of MTA FillApex sealer showed higher parameters than AH Plus sealer even if it was not significant. The lowest percent of voids was recorded at the apical third for both tested sealers. The correlation between leakage and voids percentage was nonsignificant. Conclusion Calcium silicate root canal sealer (MTA FillApex) and AH Plus sealer can provide adequate seal with low voids percent. None of the root canal filled teeth were gap-free. Voids percentage cannot be used as an indicator for sealing ability.