Avaliação da influência de materiais obturadores endodônticos sobre a resistência de união adesiva de pinos de fibra de vidro cimentados

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Qualitative SEM/EDS analysis of microleakage and apical gap formation of adhesive root-filling materials

Objective: The aim of this study was to compare the correspondence between gap formation and apical microleakage in root canals filled with epoxy resin-based (AH Plus) combined or not with resinous primer or with a dimethacrylate-based root canal sealer (Epiphany). Material and Methods: Thirty-nine lower single-rooted human premolars were filled by the lateral condensation technique (LC) and immersed in a 50-wt% aqueous silver nitrate solution at 37 degrees C (24 h). After longitudinal sectioning, epoxy resin replicas were made from the tooth specimens. Both the replicas and the specimens were prepared for scanning electron microscopy (SEM). The gaps were observed in the replicas. Apical microleakage was detected in the specimens by SEM/energy dispersive spectroscopy (SEM/EDS). The data were analyzed statistically using an Ordinal Logistic Regression model and Analysis of Correspondence (alpha=0.05). Results: Epiphany presented more regions containing gaps between dentin and sealer (p<0.05). There was correspondence between the presence of gaps and microleakage (p<0.05). Microleakage was similar among the root-filling materials (p>0.05). Conclusions: The resinous primer did not improve the sealing ability of AH Plus sealer and the presence of gaps had an effect on apical microleakage for all materials.

Clinical microscopic analysis of protaper retreatment system efficacy considering root canal thirds using three endodontic sealers

To evaluate the efficacy of ProTaper Universal rotary retreatment system and the influence of sealer type on the presence of filling debris in the reinstrumented canals viewed in an operative clinical microscope. Forty-five palatal root canals of first molars were filled with gutta-percha and one of the following sealers: G1, EndoFill; G2, AH Plus; G3, Sealapex. The canals were then reinstrumented with ProTaper Universal rotary system. Roots were longitudinally sectioned and examined under an operative clinical microscope (10x), and the amount of filling debris on canal walls was analyzed using the AutoCAD 2004 software. A single operator used a specific software tool to outline the canal area and the filling debris area in each third (cervical, middle, and apical), as well as the total canal area. Data were analyzed by Kruskal-Wallis test and Tukey test at P < 0.05. Sealapex demonstrated significant differences in the average of filling debris area/canal among the 3 thirds. This group revealed that apical third showed more debris than the both cervical and middle third (P < 0.0001). Endofill presented significantly more filling debris than Sealapex in the cervical third (P < 0.05). In the middle (P = 0.12) and apical third (P = 0.10), there were no differences amongst groups. Debris was left in all canal thirds, regardless of the retreatment technique. The greatest differences between techniques and sealers were found in the cervical third. Microsc. Res. Tech. 75:12331236, 2012. (C) 2012 Wiley Periodicals, Inc.

Efficacy of NiTi rotary instruments in removing calcium hydroxide dressing residues from root canal walls

The aim of this study was to evaluate the efficacy of three rotary instrument systems (K3, Pro Taper and Twisted File) in removing calcium hydroxide residues from root canal walls. Thirty-four human mandibular incisors were instrumented with the Pro Taper System up to the F2 instrument, irrigated with 2.5% NaOCl followed by 17% EDTA, and filled with a calcium hydroxide intracanal dressing. After 7 days, the calcium hydroxide dressing was removed using the following rotary instruments: G1. - NiTi size 25, 0.06 taper, of the K3 System; G2 - NiTi F2, of the Pro Taper System; or G3 - NiTi size 25, 0.06 taper, of the Twisted File System. The teeth were longitudinally grooved on the buccal and lingual root surfaces, split along their long axis, and their apical and cervical canal thirds were evaluated by SEM (x1000). The images were scored and the data were statistically analyzed using the Kruskall Wallis test. None of the instruments removed the calcium hydroxide dressing completely, either in the apical or cervical thirds, and no significant differences were observed among the rotary instruments tested (p > 0.05).

Influence of prior 810-nm-diode intracanal laser irradiation on hydrophilic resin-based sealer obturation

Dentin wall structural changes caused by 810-nm-diode laser irradiation can influence the sealing ability of endodontic sealers. The objective of this study was to evaluate the apical leakage of AH Plus and RealSeal resin-based sealers with and without prior diode laser irradiation. Fifty-two single-rooted mandibular premolars were prepared and divided into 4 groups, according to the endodontic sealer used and the use or non-use of laser irradiation. The protocol for laser irradiation was 2.5W, continuous wave in scanning mode, with 4 exposures per tooth. After sample preparation, apical leakage of 50% ammoniacal silver nitrate impregnation was analyzed. When the teeth were not exposed to irradiation, the Real Seal sealer achieved the highest scores, showing the least leakage, with significant differences at the 5% level (Kruskal-Wallis test, p = 0.0004), compared with AH Plus. When the teeth were exposed to the 810-nm-diode laser irradiation, the sealing ability of AH Plus sealer was improved (p = 0282). In the Real Seal groups, the intracanal laser irradiation did not interfere with the leakage index, showing similar results in the GRS and GRSd groups (p = 0.1009).

Fracture susceptibility of endodontically treated teeth

Aim: To assess the influence of cervical preparation on fracture susceptibility of roots. Material and methods: During root canal instrumentation, the cervical portions were prepared with different taper instruments: I: no cervical preparation; II: #30/.08; III: #30/.10; IV: #70/.12. The specimens were sealed with the following filling materials (n = 8), A: unfilled; B: Endofill/gutta-percha; C: AH Plus/gutta-percha; D: Epiphany SE/Resilon. For the fracture resistance test, a universal testing machine was used at 1 mm per minute. Results: anova demonstrated difference (P < 0.05) between taper instruments with a higher value for group I (205.3 +/- 77.5 N) followed by II (185.2 +/- 70.8 N), III (164.8 +/- 48.9 N), and IV (156.7 +/- 41.4 N). There was no difference (P > 0.05) between filling materials A (189.1 +/- 66.3 N), B (186.3 +/- 61.0 N), C (159.7 +/- 69.9 N), and D (176.9 +/- 55.2 N). Conclusions: Greater cervical wear using a #70/.12 file increased the root fracture susceptibility, and the tested filling materials were not able to restore resistance.

Push-out strength of root fillings with or without thermomechanical compaction

Carneiro SMBS, Sousa-Neto MD, Rached-Junior FA, Miranda CES, Silva SRC, Silva-Sousa YTC. Push-out strength of root fillings with or without thermomechanical compaction. International Endodontic Journal, 45, 821828, 2012. Abstract Aim To evaluate the influence of thermomechanical compaction (Taggers hybrid technique THT) on the push-out strength of several root filling materials to root dentine. Methodology Root canals of eighty roots in human canines were prepared with the ProTaper system and filled with one of the following materials, using either lateral compaction (LC) (n = 40) or THT (n = 40): AH Plus/gutta-percha (GP) (n = 10), Sealer 26/GP (n = 10), Epiphany SE/Resilon (n = 10) and Epiphany SE/GP (n = 10). Three 2-mm-thick dentine slices were obtained from each third of each root. The root filling in the first slice was subjected to a push-out test to evaluate the bond strength of the materials to intraradicular dentine. Data (in MPa) were analysed using anova and post hoc Tukeys test (P < 0.05). Failure mode was determined at x25 magnification. The other two slices were prepared for scanning electron microscopy (SEM) to examine the surface of the filling materials. Results Lateral compaction (1.34 +/- 1.14 MPa) was associated with a significantly higher bond strength (P < 0.05) than the THT (0.97 +/- 0.88 MPa). AH Plus/GP (2.23 +/- 0.83 MPa) and Sealer 26/GP (1.86 +/- 0.50 MPa) had significantly higher bond strengths than the other materials and differed significantly from each other (P < 0.05). There was a significant difference (P < 0.05) between the coronal (1.36 +/- 1.15 MPa), middle (1.14 +/- 1.05 MPa) and apical thirds (0.95 +/- 0.83 MPa). Considering the technique and root filling material interaction, AH Plus/GP-LC was associated with the highest mean values (2.65 +/- 0.66 MPa) (P < 0.05). Sealer 26/GP-LC (2.10 +/- 0.46 MPa), AH Plus/GP-THT (1.81 +/- 0.78 MPa) and Sealer 26/GP-TH (1.63 +/- 0.44 MPa) had intermediate values that were not significantly different from each other (P > 0.05). Epiphany SE was associated with the lowest mean values (3.70 +/- 0.86 MPa) (P < 0.05), regardless of the root filling technique and type of solid material (cone). Adhesive failures predominated in the specimens filled with Epiphany SE, whilst mixed and cohesive failures were more frequent in those filled with AH Plus and Sealer 26, regardless of the root filling technique. SEM analysis revealed that LC produced a dense and well-compacted filling whilst the use of a hybrid thermomechanical technique resulted in the solid material (GP or Resilon) intermingled within sealer to form a nonhomogenous mass. Conclusion Lateral compaction was associated with higher bond strengths of the materials to intraradicular dentine than a hybrid technique using thermomechanical compaction. The greatest push-out strengths were obtained when the canals were filled with LC of AH Plus and GP cones.

Evaluation of epoxy resin sealer after three root canal filling techniques by confocal laser scanning microscopy

The aim of this study was to evaluate the penetration of endodontic sealer into the dentin tubules, the integrity of the sealer layer perimeter, and the sealer area at the apical third after different filling techniques by confocal laser scanning microscopy (CLSM). Forty-five mandibular premolars were mechanically prepared with ProTaper files, until F5 file. Thereafter, they were filled with an epoxy-resin sealer (AH Plus) mixed with Rhodamine B dye (0.1% proportion) and allocated in three groups: Group 1, single master cone; Group 2, cold lateral compaction; and Group 3, Thermafil. For confocal laser scanning microscopy analysis, the specimens were transversely sectioned at 4 mm from the apex. The images at x10 and x40 were analyzed by Imagetool 3.0 software. Significant differences were not found among the three experimental groups according the dentin-impregnate area by the sealer (P = 0.68) and between the sealer and root canal perimeter (P = 0.18). However, root canal filling techniques were significantly different when apical sealer areas were compared (P = 0.001). Thermafil group showed smaller sealer areas (8.09%) while cold lateral compaction and gutta-percha master cone showed similar areas (17.37 and 21.18%, respectively). The dentin-impregnated area was not dependent on the root canal filling technique. Single master cone, cold lateral condensation and Thermafil techniques presented integrity of the sealer perimeter close to 100% and Thermafil resulted in a significantly thinner sealer layer. Microsc. Res. Tech. 75:12771280, 2012. (C) 2012 Wiley Periodicals, Inc.

Comparative analysis of Enterococcus Faecalis biofilm formation on different substrates

Introduction: The aim of this study was to compare Enterococcus faecalis biofilm formation on different substrates. Methods: Cell culture plates containing growth medium and E. faecalis (ATCC 29212) were used to grow biofilm on bovine dentin, gutta-percha, hydroxyapatite, or bovine bone. Substrates were incubated at 37 C for 14 or 21 days, and the medium was changed every 48 hours. After the growth induction periods, specimens (n = 5 per group and per induction period) were stained by using Live/Dead, and the images were analyzed under a confocal microscope. The total biovolume (mm3), live bacteria biovolume (mm3), and substrate coverage (%) were quantified by using the BioImage_L software. Results obtained were analyzed by nonparametric tests (P = .05). Results: Biofilm formation was observed in all groups. Gutta-percha had the lowest total biovolume at 14 days (P < .05) and hydroxyapatite the highest at 21 days (P < .05). No significant difference was observed in green biovolume at 14 days. At 21 days, however, hydroxyapatite had the highest volume (P < .05). The percentages of coverage were similar among all substrates at 21 days (P > .05), but at 14 days, bovine bone presented the highest coverage (P < .05). Conclusions: E. faecalis was capable of forming biofilm on all substrates during both growth periods; hydroxyapatite presented the highest rates of biofilm formation. The type of substrate influenced the biofilm characteristics, according to the parameters evaluated

Evaluation of apically extruded debris during endodontic retreatment

Introduction: A growing interest to preserve teeth into the mouth by patients resulted in the increasing number of endodontic retreatments, and when these happen, many different types of irritants are extruded through the foramen. Objective: This study analyzed in vitro the amount of debris extruded through the foramen using four instrumentation techniques during endodontic retreatment. Material and methods: Forty mesial-buccal roots of first molars were selected, instrumented with anatomical diameter up to size #30 ISO file and then obturated with gutta-percha and grossman sealer by lateral condensation. After, they were separated and randomly allocated into four groups with 10 teeth each for the endodontic retreatment procedure: G1 – conventional technique + solvent, G2 – conventional technique without solvent, G3 – ProTaper retreatment + solvent, G4 – ProTaper retreatment without solvent. In all groups, gutta-percha in the coronal portion was removed by using size 1-3 Gates Glidden drills. All teeth were irrigated with distilled water. The debris extruded through the foramen were collected and weighed by an analytical balance. Results: Group 4 had the lowest average for material extrusion through the foramen followed by groups 2, 3 and 1. When Tukey test for statistical analysis was applied, no significant difference among groups were found (p = 0.5664). Conclusion: We conclude that all instrumentation techniques used in this study produced debris which goes beyond the foramen.

Healing of a tooth with an overinstrumented apex, extensive transportation and periapical lesion using a 5 mm calcium hydroxide apical plug: an 8-year follow-up report

Besides the risk of filling material extrusion throughout the apex, a satisfactory apical seal can be difficult to achieve in canals with open apices or iatrogenic enlargements of the apical constriction. These situations pose a challenge to root canal filling. This paper describes the root canal filling of a maxillary right canine with an overinstrumented apex, complete loss of the apical stop, extensive canal transportation and apical periodontitis. A 5 mm calcium hydroxide apical plug was placed before root canal filling. The plug was made by soaking paper points with saline, dipping the points in calcium hydroxide powder and then applying it to the apex several times, until a consistent apical plug was obtained. The canal was then irrigated with saline in order to remove any residual calcium hydroxide from the root canal walls, dried with paper points and obturated with an inverted #80 gutta-percha cone and zinc oxide-eugenol based sealer by the lateral condensation technique. An 8-year radiographic follow-up showed formation of mineralized tissue sealing the apical foramen, apical remodeling and no signs of apical periodontitis.

[The patent nasopalatine duct. A rare anomaly and diagnostic pitfall]

The patent nasopalatine duct is a rare anomaly in the anterior maxilla. During the early fetal period, a bilateral and epithelium-lined duct is formed within the primary palatal process as an oro-nasal communication. However, the duct obliterates and degenerates before birth. A persisting patent or through-and-through nasoplatine duct is therefore considered a developmental anomaly. A patent nasopalatine duct normally presents as one (or two) tiny openings lateral or posterior to the incisive papilla. In such a case, the ducts can be partially or completely probed with gutta-percha points with subsequent radiographic imaging. The patients report strange sensations such as squeaking noise, palatal drainage, nasal regurgitation, or airway communication between nasal and oral cavities; however, patients rarely complain about pain. About 40 cases have been documented in the literature. We describe two patients who have been referred to our department for evaluation of "sinus tracts" in the anterior palate. Since a patent nasopalatine duct can become a diagnostic pitfall, a thorough inspection of the mucosa around the incisive papilla is essential to avoid unnecessary endodontic or surgical interventions in the area of the central maxillary incisors.

A 5-year review of teeth filled with the noninstrumentation technology

AIM: The aim of this Case Series was to evaluate the radiographic quality of root fillings performed 5 years previously using the noninstrumentation technology (NIT)-obturation method and to assess radiographically the outcome of these root canal treatments. METHODOLOGY: Seventeen patients requiring root canal treatment participated in this study and were re-evaluated after 5 years. After instrumentation with K-Flexofiles, Calcium-Hydroxide inter-appointment dressing, re-entry and copious irrigation with NaOCl, the teeth were root filled using the NIT. RESULTS: Immediately after obturation the root fillings were (-0.78 +/- 0.11 mm) short when taking the radiographic apex as a reference point. After 60 months these values were -0.85 +/- 0.11 mm. No statistical difference was found (P > 0.05). In the periapical region, PAI rating 1 and 2 increased from 20.1% to 75.6% after 60 months. CONCLUSIONS: * This prospective Case Series demonstrated the performance of the NIT-obturation method in vivo. * Root canals filled by the reduced-pressure method using sealer combined with gutta-percha cones showed good radiographic quality. * Periapical healing after 5 years was comparable with conventional filling techniques.

Restauración de incisivo inferior fracturado mediante procedimientos de invasión mínima : reporte de un caso clínico

La odontología está inmersa en un nuevo paradigma: no se puede pensar en ninguna técnica restauradora sin que participen fenómenos de adhesión. El desarrollo de pernos de fibra de vidrio, sumado a los procedimientos de restauraciones adhesivas puede utilizarse como uno de los tantos recursos de la odontología de invasión mínima. Los pernos de fibra de vidrio ofrecen varias ventajas: comportamiento anisótropo, módulo de elasticidad bajo, buena resistencia mecánica, el lecho que aloja al perno de fibra requiere de una mínima preparación y se cementan con cementos adhesivos con carga, permitiendo de esta manera obtener una superficie homogénea que se interpone entre el perno de fibra y los tejidos dentales, conectándolo a los tejidos del conducto y sustituyendo mecánicamente la dentina. El caso clínico que se reporta se presentó para su resolución en la Clínica Integrada III F. O. UNCuyo durante el año lectivo 2009. El paciente presentaba una fractura amelodentinaria desde hacía cuatro años, con compromiso de la vitalidad y un proceso periapical. Durante los procedimientos endodónticos se realizó una perforación de la pared del conducto que se selló mediante la colocación de hidróxido de calcio y la obturación del mismo con conos de gutapercha. Se efectuó el seguimiento clínico y radiográfico del caso en donde se constató la reparación del proceso apical y luego se procedió a la restauración del elemento dentario con resinas compuestas con la ayuda de un poste de fibra de vidrio cementado con cemento resinoso. Dadas las características del tratamiento endodóntico realizado, se decidió dejar más porción del cono de gutapercha a pesar de lo aconsejado por numerosos autores, ya que de esta manera se aseguró el sellado de la perforación radicular para evitar de esta manera la nanofiltración hacia el interior del elemento dentario.

Pacific Ocean, 1899 (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: Pacific Ocean : compiled from Admiralty surveys & other official sources by the India-Rubber, Gutta-Percha & Telegraph Works Co. It was published by J.D. Potter in [1899]. Scale [ca. 1:15,000,000]. The image inside the map neatline is georeferenced to the surface of the earth and fit to a non-standard 'Mercator' projection with the central meridian at 170 degrees west. All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. Note: The central meridian of this map is not the same as the Prime Meridian and may wrap the International Date Line or overlap itself when displayed in GIS software. This map shows features such as drainage, territorial boundaries, shoreline features, and more. Relief shown by hachures. Depths shown by soundings. Shows routes of Admiralty surveys. This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection and the Harvard University Library as part of the Open Collections Program at Harvard University project: Organizing Our World: Sponsored Exploration and Scientific Discovery in the Modern Age. Maps selected for the project correspond to various expeditions and represent a range of regions, originators, ground condition dates, scales, and purposes.