Eduardo Diogo Gurgel-Filho

Radiopacity and histological assessment of Portland cement plus bismuth oxide

OBJECTIVEnThe present study evaluated the subcutaneous connective tissue reactions and the radiopacity of MTA, Portland cement (PC), and Portland cement plus bismuth oxide (BO).nnnSTUDY DESIGNnForty rats were divided into 5 groups (n = 8 per group): A1: Control (empty capsule); A2: Pro-Root MTA; A3: PC; A4: PC + BO 1:1; and A5: PC + BO 2:1. Polyethylene tubes were filled with the test materials and standardized radiographic images were taken. Histological evaluation was done after 7 and 60 days. Student t test and Fishers test were used in the statistical analysis (P < .05).nnnRESULTSnThe radiopacity of the materials were in decreasing order: A2 > A4 > A5 > A3. No differences were found for the tissue response in the 2 experimental periods. A positive correlation between BO concentration and radiopacity of PC was determined.nnnCONCLUSIONnThe histological evaluation suggests that all studied materials were biocompatible at 7 and 60 days.

Response of mice connective tissue to three different endodontic materials

The aim of this study was to evaluate the biocompatibility of mineral trioxide aggregate (MTA) Bio and Portland cement (PC) and compare with those of ProRoot MTA. Polyethylene tubes were filled with materials and placed into dorsal subcutaneous connective tissue of Wistar albino rats. After 7, 30, and 60 days after the surgical procedure, the implants with the surrounding tissue were removed. Tissue samples were subjected to histological processing, and sections were stained with hematoxylin and eosin. Sections were evaluated for the intensity of inflammation, predominant cell type, presence of fibrous capsule and granulation tissue. Data were submitted to Kruskal‐Wallis test at a significant level of P ≤ 0.05. No statistical differences were observed at any evaluated condition among tested materials (P > 0.05). Statistically significant differences were observed between mean inflammatory scores, cell types and granulation tissue of the same material in different experimental periods (P < 0.05). Can be concluded that biocompatibility of MTA bio and PC were comparable with that of ProRoot MTA. Microsc. Res. Tech. 76:311–315, 2013.

Chemical composition and thermal behavior of five brands of thermoplasticized gutta‑percha

Objective: The aim of this study was determine the chemical composition and thermal behavior of Thermafil (TH), Microseal Cone (MC), Microseal Microflow (MF), Obtura (OB) and Obtura Flow (OF). In addition, their thermal behavior in response to temperature variations was studied by differential scanning calorimetry (DSC) to determine the temperature at which gutta-percha switches from the beta to alpha form, and from the alpha to the amorphous phase. Materials and Methods: The organic and inorganic fractions were separated by dissolution in chloroform. Gutta-percha (GP) was precipitated with acetone. The inorganic fraction was analyzed via Elemental Microanalysis. Energy Dispersive X-ray Microanalysis and X-ray Diffraction were used to identify the chemical elements and compounds (BaSO 4 and ZnO). Thermal analysis was conducted using DSC. Results: The organic and inorganic fractions ranged from 21.3% and 26.9% of weights, respectively. MC and MF showed the highest percentages of organic compounds (P = 0.0125). All specimens exhibited two crystalline transformations when heated from ambient temperature to 130°C. MC presented the highest percentage of GP. Conclusions: No correlation was observed between chemical composition and thermal behavior. Each of the products showed thermal behavior that is typical of beta-phase gutta-percha.

Coronal leakage of four intracanal medications after exposure to human saliva in the presence of a temporary filling material.

AIMnTo determine the time required for the recontamination of root canals medicated with four different materials.nnnMATERIALS AND METHODSnA total of 60 intact, caries-free, human single-rooted teeth with straight roots were selected for this study. After chemo-mechanical preparation they must be changed in the specimens into seven groups: 10 teeth medicated with calcium hydroxide (Ca(OH) 2) + Camphorated paramonochlorophanol (CPMC) (G.1); 10 medicated with 2.5% Sodium hypochlorite (NaOCL) (G.2); 10 medicated with 2% Chlorhexidine gluconate (CHX) in gel (G.3); 10 medicated with 2% CHX in gel + Ca(OH) 2 (G.4); 10 without intracanal medicament and sealed with a coronal temporary filling (G.5). Five teeth were without intracanal medicament and coronally unsealed, used as the positive control group (PC) (G.6) and 5 teeth with intact crowns used as the negative control group (NC) (G.7). Glass vials with rubber stoppers were adjusted for use. The medicaments were prepared and injected into the root canals using sterile plastic syringes. An apparatus was used to evaluate for 30 days leakage. The chamber was filled with 3 ml of human saliva and Brain Heart Infusion (BHI) broth, incubated at 37 degrees C and checked daily for the appearance of turbidity in the BHI broth.nnnRESULTSnRecontamination was detected after an average time of 2.6 days in group 2, 15.9 days in group 3, 30 days in group 1, 27.6 days in group 4, 2.9 days in group 5, 1 day in the positive control, and there was no contamination in the negative control group.nnnCONCLUSIONnThe NaOCl group showed the highest worst average of recontamination; on the other hand, high averages were also shown by Ca(OH) 2 + CPMC and Ca(OH) 2 + 2% CHX in gel.

Cyclic fatigue resistance of different continuous rotation and reciprocating endodontic systems

Objective: The objective of this study is to compare the cyclic fatigue resistance of nine types of endodontic instruments of nickel–titanium. Materials and Methods: Five files of 25 mm of length of each group: Reciproc (RC) R25; WaveOne (WO) Primary; Unicone (UC) L25 25/0.06; K3XF 25/0.06; ProTaper Universal F2 (PTF2); ProTaper Next X2 (PTX2); Mtwo 25/0.06; BioRaCe 25/0.06; One Shape L25 25/0.06 were subjected to a cyclic fatigue resistance test on a mechanical apparatus. The mean fracture time was analyzed statistically by one-way analysis of variance and Tukeys honest significant difference post hoc test, with significance set at P< 0.05. Conclusion: It was observed that the groups PTX2, RC, R25, UC L25 25/0.06, and WO Primary presented greater cyclic fracture resistance than the other groups (P< 0.001).