Biocompatibility of a resin-modified glass-ionomer cement applied as pulp capping in human teeth

Purpose: to evaluate the human pulp response following pulp capping with calcium hydroxide (CI-I, Group 1), and the resin-modified glass-ionomer Vitrebond (VIT, Group 2). Materials and Methods: Intact teeth with no cavity preparation were used as control Group (ICG, Group 3). Buccal Class V cavities were prepared in 34 sound human premolars. After exposing the pulps, the pulp capping materials were applied and the cavities were Filled using Clearfil Liner Bond 2 bonding agent and Z100 resin-based composite. The teeth were extracted after 5, 30, and from 120 to 300 days, fixed in 10% buffered formalin solution, and prepared according to routine histological techniques. 6-mu m sections were stained with hematoxylin and eosin, Masson's trichrome, or Brown gr Brenn technique for bacterial observation. Results: At 5 days, CH caused a large zone of coagulation necrosis, the mononuclear inflammatory reaction underneath the necrotic zone was slight to moderate. VIT caused a moderate to intense inflammatory pulp response with a large necrotic zone. A number of congested venules associated with plasma extravasation and neutrophilic infiltration was observed. Over time, only CH allowed pulp repair and complete dentin bridging around the pulp exposure site. VIT components displaced into the pulp tissue triggered a persistent inflammatory reaction which appeared to be associated with a lack of dentin bridge formation. After 30 days a few histological sections showed a number of bacteria on the lateral dentin walls. In these samples the pulp response was similar to those samples with no microleakage. VIT was more irritating to pulp tissue than CH, which allowed pulp repair associated with dentin bridge formation. These results suggested that VIT is not an appropriate dental material to be used in direct pulp capping for mechanically exposed human pulps.

Fracture strength of incisor crowns after intracoronal bleaching with sodium percarbonate

Objectives: To compare the fracture resistance of bovine teeth after intracoronal bleaching with sodium percarbonate (SPC) or sodium perborate (SP) mixed with water or 20% hydrogen peroxide (HP). Materials and methods: Fifty extracted bovine teeth were divided into four experimental groups (G1G4) and one control (n = 10) after endodontic treatment. Following root canal obturation, a glass ionomer barrier was placed at the cementoenamel junction. After that, the pulp chambers were filled with: G1 SP with water; G2 SP with 20% HP; G3 SPC with water; and G4 SPC with 20% HP. No bleaching agent was used in the control group. Coronal access cavities were sealed with glass ionomer and specimens were immersed in artificial saliva. The bleaching agents were replaced after 7 days, and teeth were kept in artificial saliva for an additional 7 days, after which the pastes were removed and the coronal access cavities were restored with glass ionomer. Crowns were subjected to compressive load at a cross head speed of 0.5 mm min-1 applied at 135 degrees to the long axis of the root by an EMIC DL2000 testing machine, until coronal fracture. Data were statistically analysed by anova and Tukey test. Results: No differences in fracture resistance were observed between the experimental groups (P > 0.05). However, all experimental groups presented lower fracture resistance than the control group (P < 0.05). Conclusion: SPC and SP led to equal reduction on fracture resistance of dental crowns, regardless of being mixed with water or 20% HP.

Release and diffusion of hydroxyl ion from calcium hydroxide-based medicaments

The release and diffusion of hydroxyl ions (OH-) of calcium hydroxide (Ca(OH)2)-based intracanal medications may be affected by the association with other substances. The aim of this study was to evaluate the diffusion of OH- ions through root dentin by the medications: G1, Ca(OH)2/saline; G2, Calen; G3, Calen/camphorated p-monochlorophenol (CMCP); and G4, Calen/0.4% chlorhexidine (CHX). Root canals from bovine teeth were prepared in a standardized manner. A cavity until dentin was prepared in the middle third of the root surface of each specimen. The external surface of the root was made impermeable using a layer of adhesive, except the prepared cavity. The root canals were filled with different medications, and teeth were individually stored in flasks containing 10 ml distilled water at 37 degrees C. The water pH was measured at 1, 3, 7, 14, 21, 30, and 60 days. Data obtained were subjected to anova and Tukeys tests. Increase in pH was observed at 3 days for Calen/CHX and from 7 to 14 days for the other mixtures. Calen paste promoted pH increase up to 21 days. Calen/CMCP had the highest pH up to 21 days, and all groups had similar results at 30 days. At 60 days, the greatest pH values were observed for Calen/CMCP and Calen alone. All different formulations of Ca(OH)2-based medications tested release hydroxyl ion that can diffuse through the dentin.

Enterococcus faecalis leakage of root canal sealers: an ex vivo study

The aim of this ex vivo study was to evaluate bacterial penetration after filling root canals using 3 different techniques. Three experimental groups of 25 teeth each, obturated with lateral-warm-vertical condensation of gutta-percha, Microseal technique and EndoREZ (R) system, respectively, were tested in a split chamber model system using Enterococcus faecalis and monitored for 180 days to determine bacterial penetration. A statistical analysis was performed using the Kaplan-Meier method. Median survival time was 25 days for Microseal system, 41 for lateral-warm-vertical condensation and 81 for EndoREZ (R). Significant differences were demonstrated between Microseal and EndoREZ (R) (p<0.001) and between Microseal and lateral-warm-vertical condensation technique (p<0.05). No statistically significant differences were observed between EndoREZ (R) and lateral-warm-vertical condensation. After 180 days of assessment, 20% of the EndoREZ (R) samples resisted bacterial penetration and furthermore, the EndoREZ (R) system has the potential to be a filler system compatible with other currently used systems.

Reliability of assessing dye penetration along root canal fillings using methylene blue

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Root Canal Area Increase Promoted by the EndoSequence and ProTaper Systems: Comparison by Computed Tomography

Introduction: The aim of this study was to compare the increase of the root canal area after instrumentation with EndoSequence or ProTaper rotary systems. Methods: Twenty-two mesial root canals from mandibular molars were instrumented. Teeth were mounted on a base, numbered, and divided into 2 groups; teeth from 1-11 (PT group) were instrumented by using the ProTaper system, and teeth from 12-22 (ES group) were instrumented by using the EndoSequence system. Cone beam computed tomography was performed on all teeth before and after instrumentation. Measurements at 3,5, and 7 mm as well as differences in instrument performance were statistically compared by the Student t test at 5% significance level. Results: Both systems increased significantly the root canal area (P < .05) at all levels. Comparison between the rotary systems showed significantly greater increase (P < .05) for EndoSequence at 3 mm, with no statistically significant difference (P < .05) at the other levels. Conclusions: Both rotary systems increased significantly the root canal area. (J Endod 2010;36:1179-1182)

Bond strength of different endodontic sealers to dentin: push-out test

Objective: The aim of this in vitro study was to evaluate the bond strength of different root canal sealers to dentin. Material and Methods: Forty extracted single-rooted human teeth were examined and the coronal and middle thirds of the canals were prepared with a 1.50 mm post drill (FibreKor Post System, Pentron). The teeth were allocated in two experimental groups, irrigated with 2.5% NaOCl+17% EDTA or saline solution (control group) and instrumented using Race rotary files (FKG) to a size #40 at the working length. Then, the groups were divided into four subgroups and filled with Epiphany sealer (Group 1), EndoREZ (Group 2), AH26 (Group 3) and Grossman's Sealer (Group 4). After 2 weeks of storage in 100% humidity at 37 degrees C, all teeth were sectioned transversally into 2-mm-thick discs. Push-out tests were performed at a cross-head speed of 1 mm/min using a universal testing machine. The maximum load at failure was recorded and expressed in MPa. Results: Means (+/- SD) in root canals irrigated with 2.5% NaOCl and 17% EDTA were: G1 (21.6 +/- 6.0), G2 (15.2 +/- 3.7), G3 (14.6 +/- 4.5) and G4 (11.7 +/- 4.1). Two-way ANOVA and Tukey's test showed the highest bond strength for the Epiphany's group (p < 0.01) when compared to the other tested sealers. Saline solution decreased the values of bond-strength (p < 0.05) for all sealers. Conclusion: Epiphany sealer presented higher bond strength values to dentin in both irrigating protocols, and the use of 2.5% NaOCl and 17% EDTA increased the bond strength values for all sealers.

Evaluation of the physical and chemical properties of two commercial and three experimental root-end filling materials

Objective. The aim of this study was to evaluate the pH, calcium release, setting time, and solubility of two commercially available mineral trioxide aggregate (MTA) cements (white MTA Angelus and MTA Bio), and of three experimental cements (light-cured MTA, Portland cement with 20% bismuth oxide and 5% calcium sulfate, and an epoxy resin-based cement).Study design. For evaluation of pH and calcium ion release, polyethylene tubes with 1.0 mm internal diameter and 10.0 mm length were filled with the cements and immediately immersed in flasks containing 10 mL deionized water. After 3, 24, 72, and 168 hours, the tubes were removed and the water from the previous container was measured for its pH and calcium content with a pH meter and an atomic absorption spectrophotometer. For analysis of the setting time, Gilmore needles weighing 100 g and 456.5 g were used, in accordance with the American Society for Testing and Materials specification no. C266-03. Solubility of each cement was also tested.Results. All the cements were alkaline and released calcium ions, with a declining trend over time. After 3 hours, Portland cement + bismuth oxide and MTA Bio had the highest pH and light-cured MTA the lowest. After 1 week, MTA Bio had the highest pH and light-cured MTA and epoxy resin-based cement the lowest. Regarding calcium ion release, after 3 hours, Portland cement + bismuth oxide showed the highest release. After 1 week, MTA Bio had the highest. Epoxy resin-based cement and light-cured MTA had the lowest calcium release in all evaluation periods. Regarding setting times, white MTA Angelus and MTA Bio had the shortest, Portland cement + bismuth oxide had an intermediate setting time, and the epoxy resin-based cement had the longest. The materials that showed the lowest solubility values were the epoxy resin-based cement, Portland cement + bismuth oxide, and light-cured MTA. The highest solubility values were presented in white MTA Angelus and MTA Bio.Conclusions. The white MTA Angelus and MTA Bio had the shortest setting times, higher pH and calcium ion release, and the highest solubility. In contrast, the epoxy resin-based cement and light-cured MTA showed lower values of solubility, pH, and calcium ion release. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2010; 110: 250-256)

Evaluation of the propylene glycol association on some physical and chemical properties of mineral trioxide aggregate

Duarte MAH, Alves de Aguiar K, Zeferino MA, Vivan RR, Ordinola-Zapata R, Tanomaru-Filho M, Weckwerth PH, Kuga MC. Evaluation of the propylene glycol association on some physical and chemical properties of mineral trioxide aggregate. International Endodontic Journal, 45, 565570, 2012. Abstract Aim To evaluate the influence of propylene glycol (PG) on the flowability, setting time, pH and calcium ion release of mineral trioxide aggregate (MTA). Methodology Mineral trioxide aggregate was mixed with different proportions of PG, as follows: group 1: MTA + 100% distilled water (DW); group 2: MTA + 80% DW and 20% PG; group 3: MTA + 50% DW and 50% PG; group 4: MTA + 20% DW and 80% PG; group 5: MTA + 100% PG. The ANSI/ADA No. 57 was followed for evaluating the flowability and the setting time was measured by using ASTM C266-08. For pH and calcium release analyses, 50 acrylic teeth with root-end cavities were filled with the materials (n = 10) and individually immersed in flasks containing 10 mL deionized water. After 3 h, 24 h, 72 h and 168 h, teeth were placed in new flasks and the water in which each specimen was immersed had its pH determined by a pH metre and the calcium release measured by an atomic absorption spectrophotometer with a calcium-specific hollow cathode lamp. Data were analysed by using one-way anova test for global comparison and by using Tukeys test for individual comparisons. Results The highest value of flowability was observed with MTA + 20% DW and 80% PG and the lowest values were found with MTA + 100% DW. They were significantly different compared to the other groups (P < 0.05). The presence of PG did not affect the pH and calcium release. The MTA + 100% PG favoured the highest (P < 0.05) pH and calcium release after 3 h. Increasing the PG proportion interfered (P < 0.05) with the setting time; when used at the volume of 100% setting did not occur. Conclusion The addition of PG to MTA-Angelus increased its setting time, improved flowability and increased the pH and calcium ion release during the initial post-mixing periods. The ratio of 80% DW 20% PG is recommended.

The effects of canal preparation and filling on the incidence of dentinal defects

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Effect of Ultrasonic Activation on pH and Calcium Released by Calcium Hydroxide Pastes in Simulated External Root Resorption

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Antibacterial efficacy of endodontic irrigating solutions and their combinations in root canals contaminated with Enterococcus faecalis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Ability of Gutta-Percha and Resilon to Fill Simulated Lateral Canals by Using the Obtura II System

Introduction: The aim of this study was to evaluate the ability of Resilon (Resilon Research, LLC, North Branford, CT) and 2 types of gutta-percha to fill simulated lateral canals when using the Obtura II system (Model 823-700; Obtura Spartan, Fenton, MO). Methods: Forty-five human single-rooted teeth were selected and subjected to root canal preparation. After that, simulated lateral canals were made at 2, 5, and 8 mm from the working length (WL). The specimens were divided into 3 groups (n = 15) according to the filling material used: Obtura Flow 150 gutta-percha (Obtura flow), Odous Endo Flow gutta-percha (Odous; Odous de Deus Ind e Corn. Ltda Belo Horizonte, MG, Brazil), and Resilon pellets (Resilon). Root canals were filled using the Obtura II system with the tip inserted to 3 mm from the WL. No sealer was used for root canal obturation. Specimens were subjected to a tooth decalcification and clearing method, and filling of the lateral canals was analyzed by digital radiography and photographs. The measurement of lateral canal filling was done using Image Tool software (UTHSCSA Image Tool for Windows version 3.0, San Antonio, TX). Data were statistically analyzed with the Kruskal-Wallis test at 5% significance. Results: All materials showed an ability to penetrate into the simulated lateral canals, with a minimum percentage of 73% in all thirds of the root canal. Conclusions: It was concluded that gutta-percha and Resilon are solid core materials with a lateral canal filling ability when used with the Obtura II system. (J Endod 2012;38:676-679)

Histological and histomorphometrical evaluation of furcation perforations filled with MTA, CPM and ZOE

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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.