Nonsurgical local treatment of a periapical lesion arising from trauma or bacterial infection is a promising innovative approach. The present study investigated the feasibility of developing injectable amorphous calcium phosphate nanoparticles (ACP NPs) and ACP NPs loaded with an anti-inflammatory drug; ibuprofen (IBU-ACP NPs) in the form of thermoreversible in situ gels to treat periapical lesions with the stimulation of bone formation. NPs were produced by a spray-drying technique. Different formulations of Poloxamer 407 were incorporated with/without the produced NPs to form injectable gels. A drug release study was carried out. A 3 month in vivo test on a dog model also was assessed. Results showed successful incorporation of the drug into the NPs of CP during spray drying. The particles had mean diameters varying from 100 to 200 nm with a narrow distribution. A drug release study demonstrated controlled IBU release from IBU-ACP NPs at a pH of 7.4 over 24 h. The gelation temperature of the injectable in situ gels based on Poloxamer 407 was measured to be 30 °C. After 3 months of implantation in dogs, the results clearly demonstrated that the inclusion of ACP NPs loaded with IBU showed high degrees of periapical bone healing and cementum layer deposition around the apical root tip.

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AIM: Enterococcus faecalis is one of the most resistant bacteria in necrotic teeth. That’s why the goal of this study was to determine the post-antibiotic effect of MTAD®& 2% Chlorhexidine® as root canal irrigating solution on clinical isolates of E. faecalis from infected root canals of permanent teeth, using the spectrophotometric technique. MATERIAL AND METHODS: The antibacterial efficacy of Chloramphenicol 30 mcg, Nitrofurantoin 300 mcg, Vancomycin 5 mcg, Amoxicillin/clavulanic acid 30 mcg and Ofloxacin 5 mcg against E. faecalis was compared using the Disc diffusion method. Patients were selected for this study with permanent necrotic teeth. The sterile paper point was inserted inside the infected root canal and left for 60 seconds; to obtain the microbiological sample. Postantibiotic effect of MTAD® and 2% Chlorohexidine® on E. faecalis was compared. The absorbance of bacterial growth was examined for both irrigating solutions during the first 10 hours with an hour interval, and then tested at 48, 72, 96 up to 240 hours. RESULTS: The results showed that during the first 10 hours, MTAD® showed immediate antibacterial effect and maintained its higher antibacterial activity than 2% chlorohexidine®. After 48, 72, 96 and 240 hours, both MTAD® and 2% chlorohexidine® showed the same prolonged action of post-antibiotic effect against E. faecalis with a non-significant difference. According to Antibiotic sensitivity, the results revealed MTAD® is the most effective antimicrobial drug, showing the highest zone of inhibition, followed by 2% Chlorhexidine and Nitrofurantoin 300 mcg which showed the same inhibitory activity CONCLUSION: From the current study, it can be concluded that MTAD® has a strong bactericidal effect against E. faecalis and showed the highest zone of inhibition.

Aim:To evaluate the effect of continuous ultrasonic and diode laser root canal irrigation activation techniques on apical extrusion of debris for extracted mesial mandibular molar roots. Materials and methods:Forty extracted mandibular molars were used in this study. After teeth hemi-sectioning was done, forty mesio-buccal canals were mechanically prepared using Revo-S system files according to manufacturer instructions till size AS 35# and then, roots were randomly assigned to two equal groups according to the irrigation activation method: Group (1): conventional syringe irrigation was used after mechanical preparation. This group was subdivided into 2 subgroups: Subgroup (1A): conventional syringe irrigation with no laser and subgroup (1B): conventional syringe irrigation with diode laser. Group (2): Continuous Ultrasonic Irrigation (CUI) was used after mechanical preparation and further divided into two subgroups: Subgroup (2A): Continuous Ultrasonic Irrigation (CUI) with no laser and subgroup (2B): Continuous Ultrasonic Irrigation with diode laser. A modified version of Myers and Montgomery's experimental approach was employed to assess apically extruded debris. Debris were calculated by measuring difference of weight of Eppendorf tubes (before mechanical preparation W1 and after mechanical preparation and irrigation activation W2). All measurements were done using analytical balance.Results: In all sub groups, no significant difference was shown, but the apical debris extruded was higher in subgroup (2B) (continuous ultrasonic irrigation with diode laser) then subgroup (1B) (conventional syringe irrigation with laser) followed by subgroup (2A) (continuous ultrasonic irrigation with no laser). The least amount of apical debris was in subgroup (1A) (conventional syringe irrigation with no laser). Conclusion:Diode laser and continuous ultrasonic irrigation activation could be safely used for irrigation activation with minimal effect on apical extrusion of debris.

Purpose: The current investigation was carried out to estimate the influence of single and multiple NiTi rotary file systems on prevalence of postoperative pain following root canal instrumentation using mechanical or manual glide path techniques.Materials and methods: Forty participants with a sympotomatic irreversible pulpitis of mandibular molars were contributed in this randomized, controlled, clinical double blinded study. The participants were assigned into two main groups according to the gliding path system used then further subdivided into two subgroups according to the shaping system used. After access cavity preparation and working length determination, the glide path was prepared using either the PathFiles or the K-Files then the canal shaping was carried out using either the WaveOne Gold or ProTaper Next systems then the root canals were obturated. The postoperative pain was assessed by means of the modified visual analogue scale following 6, 12, 24, 48, 72 hours and 7 days then the data were collected and analyzed. Results: Postoperative pain was significantly higher after using the WaveOne Gold and the K-Files. Conclusions: Although all systems caused postoperative pain, the mechanical glide path along with the multi-file continuous rotational systems could be considered as a promising and reliable approach in preparing the root canals with less postoperative pain.

Aim: To clinically evaluate the effect of continuous ultrasonic and diode laser 810 wave length irrigation activation techniques on postoperative pain and bacterial reduction in single visit endodontic treatment of mandibular molars. Material and methods: Forty patients requiring root canal treatment therapy for necrotic mandibular molars teeth were included in this study with age ranges between 20 and 45 years. In all cases, single visit endodontic treatment was carried out using Revo-S rotary file system in crown down sequence. NaOCl 2.5% irrigation solution was used during treatment. Patients were randomly and equally assigned into two groups according to irrigation technique. Group (1): conventional syringe irrigation and group (2): continuous ultrasonic irrigation. Each group was subdivided into two sub groups (n = 10); subgroup 1A (conventional syringe irrigation with no laser), subgroup 1B (conventional syringe irrigation with diode laser), subgroup 2A (continuous ultrasonic irrigation with no laser) and subgroup 2B (continuous ultrasonic irrigation with diode laser). Postoperative pain evaluation was done using Visual Analogue Scale (VAS) at 6, 12, 24, 36, 48 hours and 7 days postoperatively. Microbiological detection of bacterial reduction was done by taking Samples (S1 and S2) for bacterial cultures. S1 after finishing access cavity and before mechanical preparation and S2 after finishing mechanical preparation and irrigation activation and before obturation. Samples were cultured on blood agar and determined as colony forming units (CFU/mL). Microbiological bacterial reduction was calculated accordingly.  Statistical analyses were analyzed using the Mann-Whitney U test.  The significance level was set at p < 0.05. Results: In all sub groups, postoperative pain decreased by time in all time intervals but pain was significantly lower in subgroup (2B) (continuous ultrasonic irrigation with diode laser) than subgroup (1A) (conventional syringe irrigation with no laser) in all time interval. Microbiological results showed the highest bacterial reduction was in subgroup (2B) (continuous ultrasonic irrigation with diode laser) and least bacterial reduction was in subgroup (1A) (conventional syringe irrigation with no laser). Conclusion: Using diode laser and continuous ultrasonic irrigation activation techniques as adjunctive methods showed improvement in postoperative pain records and enhanced bacterial reduction in root canal therapy. Keywords: Continuous ultrasonic irrigation, diode laser 810, post-operative pain, bacterial reduction, single visit endodontic treatment.

Smear layer, XP endo Finisher, EDDY The purpose of this study was to examine the effectiveness of recent irrigant activation methods on cleanliness of the root canals and removal of the smear layer. Materials and Methods:Thirty single-rooted human mandibular premolars with single straight canals were used in this study. Root canals were mechanically prepared using Path files then BT race system till size (#35/0.04). Teeth were randomly divided into 3 groups, according to the irrigatnt activation method used. Control group (conventional irrigation) and two experimental groups according to the method used for irrigant activation in the root canal, EDDY group and XP endo finisher group (n = 10).Then teeth were split vertically to be prepared for SEM examination. The root canals were photomicrographed at magnification of 6000X to assess the presence of smear layer in coronal, middle, and apical thirds. Results showed significant increase of remaining smear layer at the apical third in all groups in comparison to middle and coronal thirds. Eddy and Xp endo finisher succeeded in removal of smear layer specially at the middle and apical third with significant difference than the conventional method without activation. There was non significant difference between Eddy and XP endo finisher in removal of smear layer at the middle and apical thirds. Conclusion: New irrigant activation systems improves the removal of smear layer than the traditional syringe method.

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