In vitro evaluation of the action of irrigating solutions associated with intracanal medications on Escherichia coli and its endotoxin in root canals

Objective: The purpose of this study was to evaluate the efficacy of auxiliary chemical substances and intracanal medications on Escherichia coli and its endotoxin in root canals. Material and Methods: Teeth were contaminated with a suspension of E. coli for 14 days and divided into 3 groups according to the auxiliary chemical substance used: G1) 2.5% sodium hypochlorite (NaOCl); G2) 2% chlorhexidine gel (CLX); G3) pyrogen-free solution. After, these groups were subdivided according to the intracanal medication (ICM): A) Calcium hydroxide paste (Calen (R)), B) polymyxin B, and C) Calcium hydroxide paste+2% CLX gel. For the control group (G4), pyrogen-free saline solution was used without application of intracanal medication. Samples of the root canal content were collected immediately after biomechanical preparation (BMP), at 7 days after BMP, after 14 days of intracanal medication activity, and 7 days after removal of intracanal medication. The following aspects were evaluated for all collections: a) antimicrobial activity; b) quantification of endotoxin by the limulus Amebocyte lysate test (LAL). Results were analyzed by the kruskal-wallis and Dunn's tests at 5% significance level. Results: The 2.5% NaOCl and CLX were able to eliminate E. coli from root canal lumen and reduced the amount of endotoxin compared to saline. Conclusions: It was concluded that 2.5% NaOCl and CLX were effective in eliminating E. coli. Only the studied intracanal medications were to reduce the amount of endotoxin present in the root canals, regardless of the irrigant used.

Action of propolis and medications against Escherichia coli and endotoxin in root canals

This study evaluated the action of propolis and intracanal medications against Escherichia coli and endotoxin. Forty-eight dental roots were contaminated with E. coli. The root canals were instrumented with propolis and divided into groups according to the type of intracanal medication: Ca(OH)(2), polymyxin B, or Ca(OH)(2) + 2% chlorhexidine gel. In the control group, saline solution was used without application of intracanal medication. Counts of colony-forming units were carried out and the endotoxin was quantified by the chromogenic Limulus amobocyte lysate assay. The results were evaluated by analysis of variance and the Dunn test (5%). Root canal irrigation with propolis was effective to completely eliminate E. coli and reduce the amount of endotoxins. All intracanal medications contributed to the significant decrease in endotoxins. Only intracanal medications may reduce the amount of endotoxins in the root canals. The greatest efficacy was observed for medications containing Ca(OH)(2). (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2010;110:e70-e74)

Apical seal of root canals with gutta-percha points with calcium hydroxide

Foi propósito deste trabalho observar se o uso de cones de guta-percha contendo Ca(OH)2, promove melhora no selamento marginal apical e, também, se apenas o cone principal contendo essa droga produz esse efeito. Assim, dentes humanos extraídos foram preparados biomecânicamente e obturados pela técnica da condensação lateral com OZE e cones de guta-percha contendo ou não Ca(OH)2. Após imersão dos espécimes em azul de metileno a 2%, em ambiente com vácuo, observou-se diferença estatisticamente significante entre os espécimes obturados com cones contendo Ca(OH)2, comparativamente aos casos obturados com cones de guta percha comuns (p=0.01). Os resultados obtidos permitiram concluir que esses cones tornam as obturações mais herméticas e que esse efeito também pode ser obtido com o emprego do cone principal da mesma fórmula, aliado a cones acessórios comuns (p=0.05).

Evaluation of periapical repair following retrograde filling with different root-end filling materials in dog teeth with periapical lesions

Objective. The objective of this study was to evaluate periapical repair following retrograde filling using different root-end filling materials.Study design. After induction of periapical lesions, 48 root canals from do teeth were partially filled. Endodontic surgery was performed and 3 different materials were used for root-end filling: Sealer 26, Sealapex plus zinc oxide, or mineral trioxide aggregate (NITA). No additional procedures were performed in the control group after partial filling of the root canal. After 180 days, the animals were killed, the rnaxillas and mandibles were removed, and specimens were submitted for histologic processing.Results. Histopathologic analysis revealed similar periapical repair for the groups in which Sealer 26, Sealapex plus zinc oxide, and MTA were used (P >.05). The control group showed unsatisfactory periapical repair W <.05).Conclusion. There was no difference in periapical tissue healing alter retrograde filling with the tested materials, which indicates that these 3 root-end filling materials are equally useful.

Effect of sodium hypochlorite and five intracanal medications on Candida albicans in root canals

The aim of this study was to evaluate the effect of 1% sodium hypochlorite and five intracanals medications on Candida albicans harvested inside root canals. The contaminated canals were irrigated with sterile saline solution and then treated as follows: (i) filled with Calen paste (calcium hydroxide/glycol polyethylene paste); (ii) filled with camphorated paramonochloro phenol (CPMC); (iii) filled with 2% iodine-iodate solution; (iv) filled with tricresol formalin; (v) filled with Calen and CPMC pastes; (vi) irrigation with 1% sodium hypochlorite and filled with no intracanal medication; and (vii) no intracanal medication was used. Canal access and the apical foramen were then sealed with Cavit and the roots were stored in a humid chamber at 37 +/- 1 degreesC for 14 days. The canals were reinstrumented and irrigated with sterile saline solution. Sterile paper points were used to transfer the root canal contents to test tubes containing sterile saline solution. Part of the suspension was harvested in Sabouraud dextrose agar with chloramphenicol and incubated at 37 +/- 1 degreesC for 48 h, CPMC was effective in 100% of the samples followed in decreasing order of effectiveness by calcium hydroxide with CPMC (70% effective), 1% sodium hypochlorite (70% effective) (p < 0.05), tricresol formalin (60% effective), 2% iodine-iodate solution (50% effective), calcium hydroxide paste (30% effective), and saline + no intracanal medication.

Analysis of Apical Root Transportation Associated with Protaper Universal F3 and F4 Instruments by Using Digital Subtraction Radiography

Introduction: The aim of this study was to assess the occurrence of apical root transportation after the use of Pro Taper Universal rotary files sizes 3 (F3) and 4 (F4). Methods: Instruments were worked to the apex of the original canal, always by the same operator. Digital subtraction radiography images were produced in buccolingual and mesiodistal projections. A total of 25 radiographs were taken from root canals of human maxillary first molars with curvatures varying from 23-31 degrees. Quantitative data were analyzed by intraclass correlation coefficient and Wilcoxon nonparametric test (P = .05). Results: Buccolingual images revealed a significantly higher degree of apical transportation associated with F4 instruments when compared with F3 instruments in relation to the original canal (Wilcoxon test, P = .007). No significant difference was observed in mesiodistal images (P = .492). Conclusions: F3 instruments should be used with care in curved canals, and F4 instruments should be avoided in apical third preparation of curved canals. (J Endod 2010;36:1052-1055)

Comportamento dos tecidos periapicais de dentes de cães após a obturação de canal com Sealapex acrescido ou não de iodoformio.

Some endodontists use iodoform in Sealapex in order to rend it more radiopac. This procedure is empiric and for this reason we decided to observe, histologically, if the iodoform introduces some modification in the biological properties of Sealapex. Thirty root canals of dogs' teeth were overinstrumented and filled, by lateral condensation technique, with gutta percha points and Sealapex, with or without iodoform. The iodoform was added in two different proportions: 30 mg or 112 mg for one centimeter of the base and one centimeter of the catalyst of Sealapex. The pieces were removed for histological studies, 6 months after the treatment. The histological results showed that Sealapex encourages apical closure by cementum deposition and that the addition of iodoform does not change that biological property.

Anaerobic microorganisms in root canals of human teeth with chronic apical periodontitis detected by indirect immunofluorescence

Aiming to assess the presence of selected anaerobic microorganisms in root canals of human teeth with chronic apical periodontitis, 25 central and lateral upper incisors presenting with radiographic evidence of chronic apical periodontitis were studied. The pulp chamber was opened under aseptic conditions and samples of the root canal content were collected with sterile absorbent paper points, which were placed and dispersed in test tubes containing reduced transport medium (RTF). Aliquots were dried on glass slides and stained by indirect immunofluorcscencc for detection of Actinomyces viscosus, Fusobacterium nucleatum, Porphyromonas gingivalis and Prevotella intermedia. The results showed a positive indirect immunofluorescence reaction in 24 of the 25 samples. Fourteen were positive for the specie Actinomyces viscosus, 12 for Prevotella intermedia, 10 for Fusobacterium nucleatum and 4 for Porphyromonas gingivalis. A semiquantitative assay was easily implemented for assessment of degree of infection by the organisms in individual cases. © Munksgaard, 1996.

Treatment of traumatized permanent incisors with crown and root fractures: A case report

A case report of the treatment of permanent incisors with crown and root fractures is presented. A radiolucent lesion at the fracture lines was treated with calcium hydroxide in the coronal fragments for 18 months. Clinically, the teeth became firm and the radiographic results after 2 years showed healing of the lesion and hard tissue filling in the space at the fracture lines. © Munksgaard, 2001.

Mineral trioxide aggregate repair of lateral root perforations

This study was conducted to observe the healing process of intentional lateral root perforation repaired with mineral trioxide aggregate (MTA). Forty-eight root canals of dogs' teeth were instrumented and filled. After partial removal of the filling, an intentional perforation was made with a bur in the lateral area of the root. The perforations were repaired with MTA or Sealapex (control group). Histological analysis occurred 30 and 180 days after treatment. Results showed no inflammation and deposition of cementum over MTA in the majority of the specimens. In the 180-day period, Sealapex exhibited chronic inflammation in all the specimens and slight deposition of cementum over the material in only three cases. In conclusion, MTA exhibited better results than the control group. Copyright © 2001 by The American Association of Endodontists.

Blood cell attachment to root surfaces treated with EDTA gel.

Root debridement generates a smear layer which contains microorganisms and toxins that could interfere in periodontal healing. For this reason, different substances have been used to remove it and to expose collagen fibers at the tooth surface. Blood element adhesion to demineralized roots and clot stabilization by collagen fibers are extremely important for the success of periodontal surgery. The aim of this study was to evaluate the different patterns of blood element adsorption and adhesion to root surfaces only irrigated with distilled water and after application of a manipulated or an industrialized EDTA gel. Thirty samples were planed, equally divided into three groups and treated with distilled water (control), a manipulated EDTA gel or an industrialized one. Immediately after, samples were exposed to fresh blood and prepared for scanning electron microscopy. Untreated planed dentin presented the best results with blood cells entrapped in a thick web of fibrin. In the manipulated EDTA group, the web of fibrin was thick with sparse blood elements. The worst result was seen with the industrialized EDTA group, in which no blood elements could be seen. Statistical difference was obtained between control and industrialized EDTA groups. Surfaces only irrigated presented the most organized fibrin network and cell entrapment.

Efficacy of EDTA-T gel for smear layer removal at root surfaces

Objective: The purpose of this in vitro study was to investigate the efficacy of EDTA gel preparation, associated with texapon detergent (EDTA-T), for removing the smear layer at human root surfaces. Method and materials: An experimental smear layer was produced by scaling using periodontal curettes, and the root surfaces were etched with the following concentrations of EDTA-T: 5%, 10%, 15%, 20%, 24%, and negative control (saline solution) for 1, 2, or 3 minutes using both passive and active methods. The surfaces were evaluated by scanning electron microscopy, and photomicrographs were evaluated in relation to smear removal. Results: All EDTA-T groups were more effective than the control group (P < .0001). EDTA-T at 15% was more effective when applied by the passive method, although this difference was not observed for the active method. The active method was statistically better than the passive method (P < .0001). Conclusion: The etching of the root surface with EDTA-T gel by active application, independently of the other factors evaluated, was effective for smear layer removal.

In vitro evaluation of apical microleakage using different root-end filling materials

The objective of this study was to evaluate the apical leakage of retrograde cavities filled with Portland Cement (Concrebrás S/A-MG-Brazil), ProRoot MTA™ (Dentsply International, Johnson City, TN, USA) and Sealapex (Kerr Corporation, Orange, California, USA) with addition of zinc oxide (Odahcam Herpo Produtos Dentários Ltda, Rio de Janeiro, RJ, Brazil). Forty-two extracted single-rooted human teeth were decoronated and used for this study. The root canals were instrumented at 1.0mm short of the apical foramen using the step-back technique to an apical ISO size 60. The roots were obturated with gutta-percha points and sealer Sealapex (Kerr Corporation-USA) and then 3mm of each root apex was sectioned at a 90° angle. Ultrasonic retrograde preparation was performed with a diamond tip to 3mm depth and the roots were randomly divided into 3 groups according to the filling material: G1-Portland, G2-ProRoot MTA, G3- Sealapex zinc oxide-added cement. The root surfaces were covered with nail varnish up to 2mm from the apical foramen, immersed in simulated tissue fluid for 30 days, and then immersed in 0.2% Rhodamine B solution for 24 hours for evaluation of marginal leakage. The results showed mean leakage of 0.75, 0.35 and 0.35 for groups 1, 2 and 3, respectively; however, Kruskal-Wallis test revealed that there was no statistically significant difference among the results (p>0.05).

In vivo microbiological evaluation of the effect of biomechanical preparation of root canals using different irrigating solutions

The aim of this study was to evaluate the antimicrobial effect of biomechanical preparation using different irrigating solutions. Seventy-eight root canals from premolars of four dogs were used. After experimental induction of periapical lesions, the root canals were prepared using the following solutions for irrigation: Group 1) 2.5% sodium hypochlorite (NaOCl); Group 2) 2% chlorhexidine (CHX); Group 3) saline solution and Group 4) control group with no biomechanical preparation. The microbiological evaluation of the root canals was performed by counting the colony forming units (CFUs) using different culture mediums. Two absorbent paper cones were used in each root canal in order to collect the microbiological samples before, and thirty days after the biomechanical preparation. The culture plates were incubated in aerobic, anaerobic and microaerophilic environment. Statistical evaluation was carried out using analysis of variance, Tukey and Student tests. The results demonstrated that there was reduction in the number of microorganisms in the NaOCl and CHX groups (p<0.05). There was greater effectiveness in the chlorhexidine group. The group that used saline solution and the control group presented an increased number of microorganisms. It can be concluded that the use of antimicrobial irrigating solutions during biomechanical preparation promotes the reduction of endodontic microbiota. However, a considerable number of microorganisms were still observed.

Influence of brush type as a carrier of adhesive solutions and paper points as an adhesive-excess remover on the resin bond to root dentin

Purpose: To evaluate the influence of the brush type as a earner of priming adhesive solutions and the use of paper points as a remover of the excess of these solutions on the push-out bond strength of resin cement to bovine root dentin. The null hypotheses were that brush type and the use of paper points do not affect the bond strength. Materials and Methods: The canals of 80 single-root bovine roots (16 mm in length) were prepared at 12 mm using the preparation drill (FRC Postec Plus, Ivoclar). Half of each root was embedded in acrylic resin and the specimens were divided into 8 groups, considering the factors brush type (4 levels) and paper point (2 levels) (n = 10): Gr 1: small microbrush (Cavi-Tip, SDI); Gr 2: Microbrush (Dentsply); Gr 3: Endobrush (Bisco); Gr 4: conventional brush (Bisco); Gr 5: Cavi-Tip (SDI) + paper points; Gr 6: Microbrush (Dentsply) + paper points; Gr 7: Endobrush (Bisco) + paper points; Gr 8: conventional brush (Bisco) + paper points. The root dentin was treated with a multistep total-etch adhesive system (All Bond 2). The adhesive system was applied using each microbrush, with and without using paper points. One fiber post was molded with addition silicon and 80 posts were made of resin cement (Duolink), The resin posts were luted (Duolink resin cement), and the specimens were stored for 24 h in water at 37°C. Each specimen was cut into 4 disk-shaped samples (1.8 mm in thickness), which were submitted to the push-out test. Results: The brush type (p < 0.0001) (small microbrush > microbrush = endobrush = conventional brush) and the use of paper points (p = 0.0001) (with > without) influenced the bond strength significantly (two-way ANOVA). The null hypotheses were rejected. Conclusion: The smallest brush (Cavi-Tip) and the use of paper points significantly improved the resin bond to bovine root dentin.