Sealability of MTA and calcium hydroxidecontaining sealers

OBJECTIVES: The aim of this study was to evaluate the apical sealability of Fillapex(®), Endo-CPM-Sealer(®) and Sealapex(®). MATERIAL AND METHODS: Ninety-four freshly extracted single-rooted teeth were selected and decoronated. All teeth were radiographed to confirm the existence of a single and straight root canal, which was prepared using Protaper Universal and 2.5% sodium hypochlorite. The teeth were randomly divided in groups of 10 specimens each according to the sealer, and the canals were filled using the single cone technique and one of the sealers. Four additional teeth were used as controls. The teeth were submitted to dye leakage with Rhodamine B for 24 h but using vacuum on the initial 15 min. Thereafter, they were cut longitudinally and the leakage was measured in a linear fashion from apex to crown. Data were analyzed by ANOVA and Tukey's tests at 5% significance level. RESULTS: Fillapex(®) and Sealapex(®) showed significantly less dye leakage than Endo-CPM-Sealer(®) (p<0.05). CONCLUSIONS: It was concluded that Fillapex(®) and Sealapex(®) were able to prevent apical dye leakage differently from Endo-CPM-Sealer(®)

Characterization of a Stem Cell of Apical Papilla Cell Line: Effect of Passage on Cellular Phenotype

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Introduction: Stem cells of the apical papilla (SCAP) have been identified as an important population of mesenchymal stem cells (MSCs) in regenerative endodontics. Preclinical studies that evaluate the various aspects of the regenerative process must use fully characterized MSCs. The phenotype of these cells when maintained in culture is crucial for the translational applicability of these studies. Thus, in this study, we aimed to characterize a SCAP cell line that preferentially expressed and maintained the required MSCs markers in culture, namely the RP-89 cell line. Methods: Apical papillae from extracted mandibular third molars from a single donor were processed for immunohistochemistry, cell culture, and,RT-PCR. SCAP were successfully cultured and maintained in culture for up to 20 passages. The expression of MSC-related molecular markers was analyzed by laser confocal microscopy, flow cytometry, and real-time RT-PCR arrays. Results: Cells within the apical papillae tissue had a widespread expression of CD90, whereas the expression of CD105 and CD73 was compartmentalized to the blood vessels and periphery, respectively. The RP-89 cell line population coexpressed CD73, CD90, and CD105 in all passages evaluated. There was a dramatic change in gene expression when cells were cultured and maintained in culture with the up-regulation of MSCs markers, inhibitors of differentiation, and sternness markers. Conversely, genes involved in the differentiation of MSCs were suppressed. Conclusions: Collectively, these results highlight the need to use fully characterized cell lines in regenerative studies and provide the foundational knowledge of gene expression modulation that occurs in cultured SCAP. (J Endod 2013;39:357-363)393357363University of Texas Health Science Center at San AntonioDepartment of EndodonticsCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)CAPES [BEX3563/103

Effect of Chlorhexidine and Ethanol on the Durability of the Adhesion of the Fiber Post Relined with Resin Composite to the Root Canal

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Introduction: The aim of this study was to investigate the effects of pretreatment of gel chlorhexidine and ethanol on the bond strength and durability of the adhesion of the fiber post relined with resin composite to the root dentin. Methods: Sixty bovine incisor roots were divided into four groups: irrigation with physiologic solution (control), 5 minutes with chlorhexidine, 1 minute with ethanol, and 5 minutes with chlorhexidine followed by 1 minute with ethanol. Fiber posts relined with resin composite were cemented with RelyX ARC (3M ESPE, St Paul, MN) and a self-etching adhesive system Clearfil SE Bond (Kuraray, Kurashiki, Japan). Each group was randomly divided into three subgroups: 24 hours of water storage, 12 months of water storage, and 12 months of oil storage. All roots were sectioned transversely in the coronal, middle, and apical regions, producing 1-mm thick slices, and the push-out test was performed. Statistical analysis was performed using analysis of variance and the Tukey test for post hoc comparisons (alpha = 0.05). Results: Immediate groups showed similar bond strength values with or without chlorhexidine and/or ethanol pretreatment (P > .05). A significant decrease in the bond strength in the control group was observed after 12 months of storage in water and oil (P < .05). The use of chlorhexidine-and/or ethanol-preserved bond strength in the groups stored in water and oil for 12 months (P < .05). Conclusions: Chlorhexidine and/or ethanol pretreatment were capable of preserving the bond strength of the fiber post relined with resin composite to root dentin for 12 months. (J Endod 2011;37:678-683)375678683Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FAPESP [2009/05183-0, 2010/00100-7

Filling of artificial lateral canals and microleakage and flow of five endodontic sealers

Aim To evaluate the flow characteristics of AH Plus, Epiphany Root Canal Sealant, Endomethasone, Pulp Canal Sealer (EWT) and Sealapex and their ability to fill artificial lateral canals and prevent microleakage. Methodology Flow of the sealers was analysed using the American Dental Association (ADA) 57 and the International Standards Organization (ISO) 6876 specifications. Two lateral canals were produced in the middle and apical third of 64 roots using 0.1 mm cylindrical drills. Lateral condensation of gutta-percha or Resilon and one or other of the sealers were used to fill the root canals. Buccal-lingual digital radiographs were exposed. After the sealer had set, the roots were immersed in Indian ink and cleared in methyl salicylate. The extent of filling and dye penetration were measured on the buccal and lingual root surfaces under 30x magnification with a stereoscope. Results AH Plus, Epiphany and Pulp Canal Sealer (EWT) complied with ADA 57 and ISO 6876 specifications. Sealapex complied with the ADA 57 specification but not with ISO 6876. Endomethasone did not comply with either specification. Filling of lateral canals was similar for the five sealers tested. Dye leakage demonstrated that AH Plus, Epiphany and Sealapex permitted less leakage than Pulp Canal Sealer (EWT) (P < 0.05). Conclusions All the sealers flowed into the 0.1 mm artificial lateral canals. AH Plus, Epiphany and Sealapex allowed less linear leakage than Pulp Canal Sealer (EWT). The flow of Endomethasone did not comply with either ADA 57 or ISO 6876 specifications and Sealapex did not comply with ISO 6876.40969269

Quantification of cultivable bacteria and endotoxin in post-treatment apical periodontitis before and after chemo-mechanical preparation

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)This clinical study was conducted to quantify cultivable bacteria and endotoxin in root canals with post-treatment apical periodontitis by correlating their levels with clinical features and to evaluate the effect of chemo-mechanical preparation (CMP) with 2 % chlorhexidine gel + 17 % EDTA on bacterial and endotoxin removal/elimination. Moreover, target strict Gram-negative anaerobic bacteria were investigated by polymerase chain reaction (PCR). Fifteen teeth with post-treatment apical periodontitis were sampled before (s1) and after (s2) CMP. Culture techniques determined the number of colony-forming units (CFU). PCR (16S rDNA) and limulus amebocyte lysate (LAL) assay were used for bacterial and endotoxin detection, respectively. Prevotella nigrescens (4/15), Prevotella intermedia (2/15), and Tannerella forsythia (2/15) were the most frequently detected species. Endotoxin was recovered in 100 % of the samples. At s1, bacteria and endotoxin were detected at a median value of 5.14 x 10(3) CFU/mL and 3.96 EU/mL, respectively. Higher levels of endotoxin were related to a larger size of radiolucent area (> 5 mm) (p < 0.05). CMP was more effective in reducing bacteria (99.61 %) than endotoxin (60.6 %) (both p < 0.05). Our findings indicated that the levels of endotoxin found in infected root canals were related to a larger size of radiolucent area in the periapical region. Moreover, CMP was effective in reducing both bacterial and endotoxin contents in post-treatment apical periodontitis.311025752583Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)FAPESP [08/58299-3, 08/57551-0, 08/56425, 10/51113-1, 10/17877-4, 10/19136-1, 11/50510-0, 11/50051-5]CNPq [302575/2009-0, 150557/2011-6

Influence of Chlorhexidine and Ethanol on the Bond Strength and Durability of the Adhesion of the Fiber Posts to Root Dentin Using a Total Etching Adhesive System

Introduction: The aim of this study was to investigate the effects of pretreatment of gel chlorhexidine (CHX) and ethanol (EtOH) on the bond strength and durability of the adhesion of the fiber post relined with resin composite to the root dentin using a total etch adhesive system. Methods: Forty bovine incisor roots were divided into four groups after phosphoric acid etching: irrigation with physiologic solution (control), 5 minutes with CHX, 1 minute with EtOH, and 5 minutes with chlorhexidine followed by 1 minute with EtOH. Fiber posts relined with resin composite were cemented with either RelyX ARC (3M ESPE, St Paul, MN) and a total etch adhesive system Scotchbond Multi-Purpose (3M ESPE). Each group was randomly divided into two subgroups: 24 hours of storage and 12 months of storage. All roots were sectioned transversely, and the push-out test was performed. Failure modes were observed, and the bond strength means were analyzed by analysis of variance and the Tukey test (alpha = 0.05). Results: CHX irrigation resulted in homogeneous bond strength values at 24 hours and 12 months of storage (P < .05). A significant bond strength decrease was noticed after 12 months of storage when irrigations were performed with physiologic solution and EtOH application only or associated with CHX (P < .05). Conclusions: The use of CHX pretreatment could preserve the bond strength of the fiber post relined with resin composite to root dentin for 12 months. The use of EtOH and CHX followed by EtOH did not preserve the bond strength of the total etch adhesive system Scotchbond Multi-Purpose. (J Endod 2011;37:1310-1315)3791310131

Design of a composite crash box for a Formula Student team car: preliminary testing and model tuning

In this work, preliminary studies towards the development of a structural carbon fibre nose for a Formula Student team car are presented. Numerical and experimental approaches have been considered to evaluate the impact behaviour of composite tubes. Then, finite element simulations are used to determine the crush stress by fitting the numerical results to the experimental data. The crush stress is also validated using quasi-static compression tests. The obtained results are compared and discussed in the framework of the future structural nose and crashbox design. The obtained results are compared and discussed in the framework of the future structural nose and crashbox design.info:eu-repo/semantics/publishedVersio

Bond strength to radicular dentin and sealing ability of AH Plus in combination with a bonding agent

Objective. To evaluate the sealing ability and bond strength of AH Plus sealer associated with the hybridization protocol of radicular dentin with Scotchbond Multi Purpose (SB). Materials and methods. Ninety palatal roots of maxillary molars were selected and divided into three groups (n = 30) according to filling protocol (G1, AH Plus/Resilon; G2, SB/AH Plus/Resilon; and G3, AH Plus/Gutta-Percha). In groups in which AH Plus + resin cones were used, dentin was hybridized before applying sealing material. For the bond strength test, 60 roots of bovine teeth were selected. Six holes were made in each root, two in the cervical, middle and apical third of the root. The roles were filled with AH Plus sealer with or without an adhesive system and submitted to push out test and the fracture mode was examined using a stereomicroscope (x32). Results. Statistical analysis showed that ScotchBond Multi Purpose (SB) + Resilon cone + AH Plus group promoted higher sealing ability than the gutta-percha + AH Plus group (p < 0.05). Bond strength was lower with SB application than without it (p < 0.05). A reverse correlation was found between bond strength and sealing ability. The fracture mode methodology revealed 22.77% of adhesive, 11.67% of cohesive and 65.55% of mixture fractures for SBMP/AH Plus protocol, whereas the AH Plus protocol indicated 86.11% of cohesive and 13.89% of mixed fractures. Conclusion. It was concluded that the use of the adhesive system Scotchbond Multi Purpose improved coronal sealing ability of AH Plus, but bond strength of sealer was reduced when adhesive was applied.7151200120