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INTRODUCTION: This study aimed to compare the incidence of dentinal crack formation by instrumentation with ProTaper Universal system (rotary, multi-file system), SafeSider (reciprocation movement, multi-file system) and Neolix (rotary, single-file system). METHODS AND MATERIALS: In this in vitro study, 60 freshly extracted mandibular first molars were randomly divided into three experimental groups (n=15) and a control group containing unprepared teeth (n=15). Instrumentation in different groups was accomplished using either ProTaper, Neolix or SafeSider systems up to 25/0.08. The teeth were then sectioned at 3, 6 and 9 mm from the apex, and observed under a stereomicroscope for presence of dentinal cracks. Data were analyzed with Chi square test, Fisher's exact test and Bonferroni correction. RESULTS: Micro cracks were seen in all experimental groups (13.3% in ProTaper, 26.7% in SafeSider and 40% in Neolix). There was a significant difference between Neolix and the control groups in microcrack formation (P=0.042). Micro cracks mainly occurred in the coronal section (9 mm). No microcrack occurred in the control group. CONCLUSION: Neolix rotary single-file system caused more dentinal cracks compared to the unprepared roots. All the instrumentation systems increased the number of micro cracks compared to unprepared teeth.
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OBJECTIVES: The purpose of the present study was the immunohistochemical evaluation of VEGF and VII factors in dog's teeth pulp revascularized with MTA and propolis. MATERIALS AND METHODS: 144 mature and immature two rooted dog's premolar canals were selected. Pulp necrosis and infection were established after 2 weeks and the disinfection of the canals was done with copious NaOCl irrigation and triantibiotic mixture (ciprofloxacin, metronidazole, and minocycline) for 3 weeks. Subsequently, the blood clot was evoked in the canal by periapical tissue irritation with a k-file. The samples were randomly divided into 6 experimental groups: propolis (groups 1, 2), MTA (groups 3, 4), and parafilm (groups 5, 6) in immature and mature teeth. The animals were sacrificed and samples were prepared for immunohistochemical evaluation of VEGF and the VIII factor. RESULTS: Tissue regeneration was seen in 64.5% of MTA, 38% of propolis, and 0% of parafilm group samples. Expression of VEGF and VIII factor in the propolis group was more than the MTA group and it showed a reduction after 3 months in comparison to 1 month. VEGF and VIII factor were seen in stromal cells in addition to endothelial vessel cells. Overall, expression of angiogenic factors was more in the open apex teeth compared to close apex ones. CONCLUSION: According to the results of this study, propolis can induce the expression of VEGF and VIII factor in infected mature and immature dog's teeth and is a suitable biomaterial for the revascularization technique.
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OBJECTIVES: During root canal preparation, apical extrusion of debris can cause inflammation, flare-ups, and delayed healing. Therefore, instrumentation techniques that cause the least extrusion of debris are desirable. This study aimed to compare apical extrusion of debris by five single-file, full-sequence rotary and reciprocating systems. MATERIALS AND METHODS: One hundred twenty human mandibular premolars with similar root lengths, apical diameters, and canal curvatures were selected and randomly assigned to six groups (n=20): Reciproc R25 (25, 0.08), WaveOne Primary (25, 0.08), OneShape (25, 0.06), F360 (25, 0.04), Neoniti A1 (25, 0.08), and ProTaper Universal. Instrumentation of the root canals was performed in accordance with the manufacturers' instructions. Each tooth's debris was collected in a pre-weighed vial. After drying the debris in an incubator, the mass was measured three times consecutively; the mean was then calculated. The preparation time by each system was also measured. For data analysis, one-way ANOVA and Games-Howell post hoc test were used. RESULTS: The mean masses (±standard deviation) of the apical debris were as follows: 2.071±1.38mg (ProTaper Universal), 1.702±1.306mg (Neoniti A1), 1.295±0.839mg (OneShape), 1.109±0.676mg (WaveOne), 0.976±0.478mg (Reciproc) and 0.797±0.531mg (F360). Compared to ProTaper Universal, F360 generated significantly less debris (P=0.02). The ProTaper system required the longest preparation time (mean=88.6 seconds); the Reciproc (P=0.008), OneShape (P=0.006), and F360 (P=0.001) required significantly less time (P<0.05). CONCLUSIONS: All instruments caused extrusion of debris through the apex. The F360 produced significantly less debris than did the ProTaper Universal.
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INTRODUCTION: This case report describes apexogenesis treatment of three molar teeth of an 8-year-old boy using three different pulpotomy agents. METHODS: Pulpotomy was performed on decayed immature molar teeth with established irreversible pulpitis and the remaining pulp was capped with either zinc oxide eugenol, ProRoot mineral trioxide aggregate or calcium-enriched mixture (CEM) cement. Teeth were restored with stainless steel crowns. RESULTS: Eighteen months clinical and radiographic follow-up revealed successful preservation of pulpal vitality with continued root development in all treated teeth. CONCLUSION: Based on this case report, CEM cement may be an alternative option for pulpotomy treatment of immature permanent molars.