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This study was designed to evaluate the effect of different movement kinematics on the deformation of TF Adaptive files using Dental Operating Microscope (DOM) and Scanning Electron Microscope (SEM). Materials and Methods: One hundred and eighty extracted human mandibular molars were selected with curved mesiobuccal canal (15o-35o). Thirty new sets of TF Adaptive files were divided into 3 groups according to the movement kinematics used (10 instruments each). Group I: 60 samples were instrumented with 10 TF Adaptive files in adaptive motion with TF Adaptive program Elements motor. Group II: 60 samples were instrumented with 10 TF Adaptive files in reciprocating motion with built-in reciprocating EndoEst motor mini, where the angle of reciprocation was set at 160° CCW and 41°CW. Group III: 60 samples were instrumented with10 TF Adaptive files in continuous rotation motion at 500rpm and torque 2 N/cm. Instruments were examined under DOM before usage and after each use for evaluation of deformation or fracture. Selected instruments from each group were evaluated using SEM. Results: there was no statistical significant difference among adaptive motion, reciprocating and continuous rotation motion in the mean deformation scores and percentage. The highest deformation scores and percentage was recorded in TF Adaptive instruments used with continuous rotation motion, however, there was no statistical significant difference. Conclusion: The innovated adaptive motion did not result in lower deformation of TF Adaptive files. Reciprocating motion produced less deformation in TF Adaptive files than did adaptive motion or continuous rotation motion, after preparing six root canals.

This study was designed to assess the effect of 17% ethylenediaminetetraacetic acid (17%EDTA) and 0.2% Chitosan as chelating agents on bond strength of CPoint obturation system to root canal dentin. Materials and Methods: Fifty extracted lower premolars were selected and prepared using Universal ProTaper rotary files then the samples were equally distributed into 2 main groups depending on the type of the final rinse. Group I:17 % EDTA, Group II: 0.2% chitosan, Control group: distilled water. Each main group was further equally distributed into 2 subgroups depending on the type of the filling material. Subgroup A: samples were obturated with gutta-percha and AH Plus sealer. Subgroup B: samples were obturated with CPoint and EndoSeqence BC sealer. The push out test was carried on using universal testing machine. The sealer penetration inside the dentinal tubules was evaluated using scanning electron microscope (SEM). Results: regarding the results of subgroup A and B, at all levels, the highest value of bond strength was recorded in samples treated with 17% EDTA, while the lowest value was recorded with the control group and there was no statistical significant difference among the tested groups except for subgroup B at the middle level, there was a statistical significant difference among the tested groups. SEM observation of sealer/ dentin interface revealed few traces of sealer penetration with samples treated with 17% EDTA. Conclusion: 17% EDTA when used as final rinse produced higher bond strength with CPoint/EndoSequence BC sealer compared to 0.2% chitosan, especially at the middle third

This study evaluated the outcome of partial exposure of dentin matrix to ethylenediaminetetraacetic acid (EDTA) and application of platelet-rich fibrin (PRF) scaffold on regeneration of necrotic immature permanent teeth in a dog model. The present study was carried out on 216 permanent immature roots in nine mongrel dogs aged 6-9 months. Pulp necrosis and periapical pathosis were induced in 180 roots. These roots were divided into five equal groups (36 roots each) according to the treatment protocol: group I: blood clot; group II: 17% EDTA solution and blood clot; group III: PRF; group IV: 17% EDTA solution and PRF; and group V: without treatment (positive control). The negative control group (group VI) represented 36 untouched normal roots for normal maturation. The groups were followed up for 1, 2 and 3 months (subgroups). Maturation of the roots was monitored by radiography and histopathology. All data were statistically analysed. Group IV exhibited the highest increase in root length and thickness, decrease in apical diameter, the highest score of vital tissue infiltration and least inflammatory scores. There was a significant difference regarding the increase in root length and thickness and decrease in apical diameter in all subgroups of the experimental and negative control groups (P ≤ .05). PRF has a better regenerative potential than the blood clot during treatment of immature permanent teeth with necrotic pulp. Inclusion of 17% EDTA solution as a final irrigation enhances the regenerative potential of both PRF and blood clot.

Purpose: This study aimed to evaluate the efficacy of Chitosan as root canal irrigant with Endovac irrigation system in removing smear layer of curved root canal walls using Scanning Electron Microscope (SEM). Materials and Methods: Fifty extracted human first mandibular molars were selected with curved mesiobuccal root (20o-35o). Samples were instrumented with Universal ProTaper rotary files till size F4 then divided into 2 main experimental groups according to the final rinse used; Group I: irrigated with 17 % EDTA Group II: irrigated with 0.2% chitosan acetate and control group, irrigated with sterile saline (10 samples). Each group was further subdivided into 2 subgroups according to the irrigating technique used; Subgroup A: using conventional needle irrigation and Subgroup B: using Endovac irrigation system. Samples were grooved longitudinally and smear layer was evaluated using SEM at the coronal, middle and apical root canal levels. The significance level was set at P≤ 0.05. Results: There was a statistically significant difference among the tested groups and the control group in the mean scores of smear layer at all root canal levels and no significant difference between irrigants used. Concerning the irrigating devices, there was no statistical significant difference between conventional irrigation and Endovac system at the coronal and apical root canal levels while at the middle level, 0.2% chitosan showed statistical significant difference with Endovac system subgroup than conventional irrigation(P ≤ 0.05). Conclusion Endovac irrigation system was effective in smear layer removal from curved root canals using either 0.2% Chitosan acetate or 17 % EDTA as finalrinse.

Aim: This study was designed to evaluate the antimicrobial effectiveness of Jojoba-Oil against endodontic pathogens involved in endodontic infection. Materials and methods: Regarding the in vitro part, sterile saline, crude Jojoba-Oil, mixtures of calciumhydroxide powder with sterile saline and calcium hydroxide powder with Jojoba-Oil were tested against selected strains (S.aureus, E.coli, E.faecalis and C.albicans) using agar diffusion method. Zones of inhibition were measured after 24, 48, 72 and 7 days incubation periods. Regarding the in vivo part, a total of forty patients were selectedaccording to specific inclusion and exclusion criteria and randomly divided into four groups (10 each) according to the assigned irrigant and intracanal medicament. Three clinical samples were collected from each patient in each group under strict aseptic conditions for microbiological studies. Results: Ca(OH)2 + Jojoba-Oil group produced the statistically significant largest mean inhibition zone against the selected strains at 24, 48 and 72 hours incubation periods. The in vivo part showed that, chemomechanicalpreparation produced a significant reduction in both bacterial and fungal count in the four experimental groups. In groups using intracanal medication, there was further significant reduction in both bacterial and fungal count compared to non-medicated groups. Conclusions: The combination of calcium hydroxide with Jojoba-Oil as a vehiclehas an antimicrobial activity comparable to calcium hydroxide mixed with saline.

Aim: This study was conducted to assess the effect of different variables on antibacterial potential of photo-activated disinfection versus the effect of a chemical disinfection solution on carious dentin. Material and Methods: Seventy freshly extracted teeth were selected, All soft caries was removed by sterile excavator and specimens were weighted by five digit microbalance to be in range of 6-10 mg, Specimen divided into three groups: Group A1: disinfected with phot-activated disinfection (PAD) and divided into four subgroups(no=10 ) according to power& application time, Subgroup1(P1T1: delivery power was 100mW, application time was 120 sec) Subgroup2 (P1T2: delivery power was 50mW application time was 30 sec) Subgroup3 (P2T1: delivery power was 100mW application time was 120 sec) Subgroup4 (P2T2: delivery power was 50mW,application time was 30 sec).Group A2: disinfected with chemical disinfectant (chlorohexidine scrub 2%).Group A3: disinfected with laser beam only & divided into two subgroups P1T1,P2T2. The specimens were plated &duplicated on blood agar then incubated in anaerobic gas pack jar at 37C for 7 days. Results: A statistically significantdifference was found among PAD, chlorohexidine, and laser groups in the percent decrease in the total bacterial count (P≤ 0.05). The greatest mean percent decrease was recorded in the PAD P1T1 followed by the cholorohexidine group, then the laser P1T1. Conclusion: The combination of toluidine blue O (TBO) and diode laser could be effective in reducing the bacterial viability. Chlorohexidine as chemical disinfectant was equally effective to photo-activated disinfectant with high delivery power and long contact time in reducing the total bacterial count.

Aim: This study was conducted to evaluate the smear layer removal efficiency of apple vinegar and EDTA when used as final rinse using scanning electron microscope (SEM) and to quantify the calcium content of intraradicular dentin after being treated with apple vinegar or EDTA using energy dispersive X-ray microanalyzer (EDX).Materials and methods: Fifty palatal roots of extracted human permanent maxillary molars with completely formed were selected and prepared with Universal Protaper rotary files. After using each file, canals were irrigated with 2 ml of 2.6% NaOCl for 1 minute. The samples were divided into 4 groups according to the final rinse used and the application time: (10 samples each), Group I: 17% EDTA for 1 minute.Group II: Apple vinegar for 1 minute. Group III: 17% EDTA for 3 minutes.Group IV: Apple vinegar for 3 minutes.Group V: control group is divided into: GV(A), Five sampleswhere the root canals were irrigated with sterile saline and GV(B), Five samples were used to assess the calcium content with energy dispersive X-ray microanalyzer (EDX), where the root canals will not receive any treatment. Results: Regarding smear layer removal, at coronal and middle thirds there was no statistically significant difference in the mean scores of smear layer produced by the tested groups.At the apical third the lowest mean smear layer score was recorded in specimens treated with apple vinegar for 1 minute (Group II) with a statistical significant difference from specimens treated with 17% EDTA for 1 minute (Group I). Regarding the calcium content, the highest mean value was recorded in specimens treated with apple vinegar for 1 minute (Group II) with statistically significant difference from that recorded in specimens treated with 17% EDTA for 1 minute (Group I) and specimens treated with apple vinegar for 3 minutes (Group IV). Conclusion: Apple vinegar was capable of adequately removing smear layer from intraradicular dentin when used as final rinse.Apple vinegar was more effective in removing smear layer from intraradicular dentin at the apical thirdcompared to 17% EDTA. Apple vinegar was more effective when used for one minute as final rinse in the removal of smear layer without affecting the calcium content of intraradicular dentin compared to 17% EDTA.

Aim: This study was conducted to evaluate the post-operative pain following single versus multiple visits endodontic retreatment. Materials and Method: Fifty cases of single rooted teeth in (29) patients had failed endodontic treatment were selected according to inclusion criteria. Using simple randomization by table, the selected patients were divided into two groups, where Group I: the retreatment was performed in single visit. Group II; the retreatment was performed in two visits and Ca (OH)2 mixed with 2% Chlorhxidin was used as intracanal medicament. The outcome of the retreatmentwas evaluated by recording post-operative pain and flare up. Results: There was no statistical significant difference in post-operative pain intensity between single and multiple visits endodontic retreatment after 24 hours as well as 7 days (P ≤ 0.05).The pain recorded was in mild category.

This study was designed to assess the impact of Chitosan-acetate as final root canal irrigant on bond strength of resin-based sealer to radicular dentin.Materials and Methods: Forty extracted human lower premolars with single roots and canals were prepared with ProTaper Universal rotary files till size F4. The samples were dispensed into 3 experimental groups according to the final rinse used and control group (10 samples each); Group I: irrigated with 0.2% chitosan acetate, Group II:17% EDTA, Group III: distilled water and control group (IV): saline. The samples were obturated by cold lateral compaction technique using AH plus sealer. Samples were sectioned into three sections (each 2 mm-thickness) from coronal, middle and apical thirds of each sample. The push out bond strength test was performed using universal testing machine. Three sections from each group were split longitudinally in buccolingual direction where the sealer/dentin interface and the sealer penetration inside the dentinal tubules was evaluated using scanning electron microscope (SEM). Results: Regarding the coronal and middle levels, there was no statistical significant difference among the tested groups. However, at the apical level, there was a statistical significant difference among the tested groups. SEM observation revealed minimal sealer penetration in group I at the apical level, while in group II, there was minimal sealer penetration at the coronal and middle levels. Regarding group III, there was minimal sealer penetration at middle level, while in control group (IV), there was no sealer penetration. Conclusion: The effect of 0.2% Chitosan acetate on the push out bond strength of AH Plus sealer was comparable to that of 17% EDTA when used as a final rinse. AH Plus sealer showed better adhesion to the dentin in the presence of smear layer especially at the apical third.

Aim: This study was designed to evaluate the effects of 0.2% chitosan, 2% chitosan and 17% EDTA chelating agents on the microhardness and mineral content of human root canal dentin. Materials and Methods: Sixty extracted single-rooted human teeth were longitudinally sectioned into 120 segments. The specimens were randomly divided into four groups according to the chelating agent used; G1: 0.2% chitosan, G2: 2% chitosan, G3: 17% EDTA and G4: saline (control group). Dentin microhardness was measured in a total of 80 specimens using Vickers diamond indenter with 300 g loadand a dwell time of 20 s. A total volume of 5 mL of each solution was used for 3min and then specimens finally flushed with 10 mL distilled water. In a total of 40 specimens, the level of three elements (calcium, phosphorus and magnesium) in each specimen was analyzed using inductively coupled plasma atomic emission spectrometry (ICPAES).Results: All tested chelating agents significantly decreased the microhardness of root canal dentin (P ≤ 0.05) and reduced the mineral content of dentin. Chitosan 2% and 17% EDTA had the statistically significant highest mean percentage reduction in microhardness compared to the control group (P ≤ 0.05) and showed the maximum loss of Ca ions from root canal dentin. Chitosan 0.2% showed less reduction in dentin microhardness and chelated Ca ions from root dentin. Conclusions: Chitosan 0.2% solution is equally effective to 17% EDTA in removing Ca ions from root canal dentin withoutmuch altering its microhardness. Accordingly, the natural product of 0.2% chitosan attracts its use as dentin chelating agent.