Congenital eruption cyst: a case report

Congenital pathologies are those existing at or dating from birth. Occurrence of congenital cystic lesions in the oral cavity is uncommon in neonates. Eruption cyst (EC) is listed among these unusual lesions. It occurs within the mucosa overlying teeth that are about to erupt and, according to the current World Health Organization (WHO) classification of epithelial cysts of the jaws, EC is a separate entity. This paper presents a case of congenital EC successfully managed by close monitoring of the lesion, without any surgical procedure or tooth extraction. Eruption of the teeth involved, primary central incisors, occurred at the fourth month of age. During this time neither the child nor mother had any complication such as pain on sucking, refusal to feed, airway obstruction, or aspiration of fluids or teeth.

Histopathological evaluation of root canal filling materials for primary teeth

This study aimed to assess the response of apical and periapical tissues of dogs' teeth after root canal filling with different materials. Forty roots from dogs' premolars were prepared biomechanically and assigned to 4 groups filled with: Group I: commercial calcium hydroxide and polyethylene glycol-based paste (Calen®) thickened with zinc oxide; Group II: paste composed of iodoform, Rifocort® and camphorated paramonochlorophenol; Group III: zinc oxide-eugenol cement; Group IV: sterile saline. After 30 days, the samples were subjected to histological processing. The histopathological findings revealed that in Groups I and IV the apical and periapical regions exhibited normal appearance, with large number of fibers and cells and no resorption of mineralized tissues. In Group II, mild inflammatory infiltrate and mild edema were observed, with discrete fibrogenesis and bone resorption. Group III showed altered periapical region and thickened periodontal ligament with presence of inflammatory cells and edema. It may be concluded that the Calen paste thickened with zinc oxide yielded the best tissue response, being the most indicated material for root canal filling of primary teeth with pulp vitality.

Periapical repair after root canal filling with different root canal sealers

The aim of this study was to evaluate periapical repair after root canal filling with different endodontic sealers. Sixty-four root canals from dog´s teeth were filled, divided into 4 groups (n=16). Root canals were instrumented with K-type files and irrigated with 1% sodium hypochlorite solution. Root canals were filled in the same session by active lateral condensation of the cones and sealers: Intrafill, AH Plus, Roeko Seal and Resilon/Epiphany System. After 90 days, the animals were euthanized and the tissues to be evaluated were processed and stained with hematoxylin and eosin. For histopathological analysis, the following parameters were evaluated: inflammatory process, mineralized tissue resorption, and apical mineralized tissue deposition. Histopathological analysis demonstrated that Intrafill had less favorable results in terms of apical and periapical repair, compared to the other sealers (p<0.05). AH Plus, Roeko Seal, and Epiphany sealers had similar and satisfactory results (p>0.05). In conclusion, AH Plus and the materials Roeko Seal and Epiphany are good options for clinical use in Endodontics.

Histopathological evaluation of different methods of experimental induction of periapical periodontitis

This study evaluated histopathologically different methods of experimental induction of periapical periodontitis. The radiographic and microbiological evaluations have been performed in a previous investigation. Fifty-seven root canals from dogs' teeth were assigned to 4 groups. In GI (n=14) and GII (n=14), the root canals were exposed to oral environment for 180 days; in GIII (n=14) and GIV (n=15) the root canals were exposed for 7 days and then the access cavities were restored and remained sealed for 53 days. The root apices of GI and GIII were perforated, whilst those of GII and GIV remained intact. After induction of periapical periodontitis, the dogs were euthanized. Serial sections were obtained and stained with hematoxylin and eosin. Data of the histopathological evaluation were submitted to Kruskal-Wallis and Dunn's tests at 5% significance level. The inflammatory periapical reaction and resorption of mineralized tissues were less intense in GII than in the other groups (p<0.05). There was no histopathological difference among the experimentally induced periapical lesions in the teeth with coronal sealing. On the other hand, when coronal sealing was not performed, greater intensity of induced periapical periodontitis was observed in the teeth with apical perforation.

Microbial distribution in the root canal system after periapical lesion induction using different methods

The aim of this study was to evaluate the microbial distribution in the root canal system after periapical lesion induction in dogs' teeth using different methods. Fifty-two root canals were assigned to 4 groups (n=13). Groups I and II: root canals were exposed to the oral cavity for 180 days; groups III and IV: root canals were exposed for 7 days and then the coronal openings were sealed for 53 days. The root apices of groups I and III were perforated, while those of groups II and IV remained intact. After the experimental periods, the animals were euthanized and the anatomic pieces containing the roots were processed and stained with the Brown & Brenn method to assess the presence and distribution of microorganisms. The incidence of microorganisms at different sites of the roots and periapical lesions was analyzed statistically by the chi-square test at 5% significance level. All groups presented microorganisms in the entire root canal system. A larger number of microorganisms was observed on the root canal walls, apical delta and dentinal tubules (p<0.05), followed by cementum and cemental resorption areas. In spite of the different periods of exposure to the oral environment, the methods used for induction of periapical periodontitis yielded similar distribution of microorganisms in the root canal system.

Vertical alveolar crest bone maintenance around implants in two-stage surgery: an in situ study in dogs

The aim of this study was to evaluate in situ changes in the alveolar crest bone height around immediate implant-supported crowns in comparison to tooth-supported crowns (control) with the cervical margins located at the bone crest level, without occlusal load. In Group I, after extraction of 12 mandibular premolars from 4 adult dogs, implants from Branemark System (MK III TiU RP 4.0 x 11.5 mm) were placed to retain complete acrylic crowns. In Group II, premolars were prepared to receive complete metal crowns. Sixteen weeks after placement of the crowns (38 weeks after tooth extraction), the height of the alveolar bone crest was measured with a digital caliper. Data were analyzed statistically by the Mann-Whitney test at 5% significance level. The in situ analysis showed no statistically significant difference (p=0.880) between the implant-supported and the tooth-supported groups (1.528 + 0.459 mm and 1.570 + 0.263 mm, respectively). Based on the findings of the present study, it may be concluded that initial peri-implant bone loss may result from the remodeling process necessary to establish the biological space, similar to which occurs with tooth-supported crowns.

Effect of repeated disinfections by microwave energy on the physical and mechanical properties of denture base acrylic resins

The present study evaluated the effect of repeated simulated microwave disinfection on physical and mechanical properties of Clássico, Onda-Cryl and QC-20 denture base acrylic resins. Aluminum patterns were included in metallic or plastic flasks with dental stone following the traditional packing method. The powder/liquid mixing ratio was established according to the manufacturer's instructions. After water-bath polymerization at 74ºC for 9 h, boiling water for 20 min or microwave energy at 900 W for 10 min, the specimens were deflasked after flask cooling and finished. Each specimen was immersed in 150 mL of distilled water and underwent 5 disinfection cycles in a microwave oven set at 650 W for 3 min. Non-disinfected and disinfected specimens were subjected to the following tets: Knoop hardness test was performed with 25 g load for 10 s, impact strength test was done using the Charpy system with 40 kpcm, and 3-point bending test (flexural strength) was performed at a crosshead speed of 0.5 mm/min until fracture. Data were analyzed statistically by ANOVA and Tukey's test (α= 0.05%). Repeated simulated microwave disinfections decreased the Knoop hardness of Clássico and Onda-Cryl resins and had no effect on the impact strength of QC-20. The flexural strength was similar for all tested resins.

Heat treatment of a direct composite resin: influence on flexural strength

The purpose of this study was to evaluate the flexural strength of a direct composite, for indirect application, that received heat treatment, with or without investment. One indirect composite was used for comparison. For determination of the heat treatment temperature, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were performed, considering the initial weight loss temperature and glass transition temperature (Tg). Then, after photoactivation (600 mW/cm² - 40 s), the specimens (10 x 2 x 2 mm) were heat-treated following these conditions: 170ºC for 5, 10 or 15 min, embedded or not embedded in investment. Flexural strength was assessed as a means to evaluate the influence of different heat treatment periods and investment embedding on mechanical properties. The data were analyzed by ANOVA and Tukey's test (α = 0.05). TGA showed an initial weight loss temperature of 180ºC and DSC showed a Tg value of 157°C. Heat treatment was conducted in an oven (Flli Manfredi, Italy), after 37°C storage for 48 h. Flexural strength was evaluated after 120 h at 37°C storage. The results showed that different periods and investment embedding presented similar statistical values. Nevertheless, the direct composite resin with treatments presented higher values (178.7 MPa) compared to the indirect composite resin (146.0 MPa) and the same direct composite submitted to photoactivation only (151.7 MPa). Within the limitations of this study, it could be concluded that the heat treatment increased the flexural strength of the direct composite studied, leading to higher mechanical strength compared to the indirect composite.

Two-dimensional gel electrophoretic protein profile analysis during seed development of Ocotea catharinensis: a recalcitrant seed species

The aim of the present work was to characterize changes in the protein profile throughout seed development in O. catharinensis, a recalcitrant species, by two-dimensional gel electrophoresis. Protein extraction was undertaken by using a thiourea/urea buffer, followed by a precipitation step with 10% TCA. Comparative analysis during seed development showed that a large number of proteins were exclusively detected in each developmental stage. The cotyledonary stage, which represents the transition phase between embryogenesis and the beginning of metabolism related to maturation, presents the highest number of stage-specific spots. Protein identification, through MS/MS analysis, resulted in the identification of proteins mainly related to oxidative metabolism and storage synthesis. These findings contribute to a better understanding of protein metabolism during seed development in recalcitrant seeds, besides providing information on established markers that could be useful in defining and improving somatic embryogenesis protocols, besides monitoring the development of somatic embryos in this species.

A new species of Sickesia (Laniatores: Stygnidae: Opiliones) and new records for the State of Piauí, Brazil

Sickesia tremembe sp. nov. is described from Piauí, Northeast Brazil (type-locality: Sete Cidades National Park, Brasileira and Piracuruca municipalities). It differs from S. usta and S. helmuti by the clavate male femur IV and chelicerae segment I with a pair of large tubercles on retrolateral surface. The Stygnidae Stygnus polyacanthus (Mello-Leitão, 1923); the Cosmetidae, Gryne pluriarcuata Mello-Leitão, 1936 and undetermined species of Paecilaema and Gryne and also representatives of Escadabiidae and Sclerosomatidae (Gagrellinae) are recorded from this state, for the first time.

Preparação de membranas de acetato de celulose organomodificadas para adsorção dos íons Cu(II), Cd(II), Mn(II) e Ni(II)

Cellulose acetate polymeric membranes had been prepared by a procedure of two steps, combining the method of phase inversion and the technique of hydrolysis-deposition. The first step was the preparation of the membrane, and together was organomodified with tetraethylortosilicate and 3-aminopropyltrietoxysilane. Parameters that exert influence in the complexation of the metallic ion, as pH, time of complexation, metal concentration, had been studied in laboratory using tests of metal removal. The membranes had presented resistance mechanics and reactivity to cations, being able to be an alternative for the removal, daily pay-concentration or in the study of the lability of metals complexed.

Hemoglobina extracelular gigante de Glossoscolex paulistus: um extraordinário sistema supramolecular hemoproteico

Giant extracellular hemoglobins are considered the summit of complexity in systems that carry oxygen, constituting an extraordinary model system to the study of hemoproteins. This class includes the hemoglobin of the annelid Glossoscolex paulistus that presents high cooperativity, great oligomeric and redox stabilities and ability of oligomeric reassociation. These properties have motivated evaluations about its utilization as prototype of artificial blood and biosensor. Kinetic studies involving autoxidation and detailed spectroscopic characterizations of its ferrous and ferric species have propitiated information about the structure-activity relationship of this macromolecule. The present review analyzes several biochemical issues, evaluating the state-of-art of this subject.

Metallochlorophylls of magnesium, copper and zinc: evaluation of the influence of the first coordination sphere on their solvatochromism and aggregation properties

In this study the role of different metal centers (magnesium, zinc and copper) on the enhancement of the hydrophilic character of metallochlorophylls, was evaluated. The solvatochromism as well as the aggregation process for these compounds in water/ethanol mixtures at different volume ratios were evaluated using Fluorescence, and Resonant Light Scattering (RLS) measurements, aiming to characterize the behavior of these compounds. Independently on the studied metallochlorophyll, the presence of at least 60% of water results in a considerable increase in the fluorescence emission, probably a direct consequence of a lower aggregation of these compounds, which is confirmed by the results from RLS measurements. Additionally, the results suggest that magnesium and zinc chlorophyll should be promising phototherapeutic agents for Photodynamic Therapy.

Influência de diferentes sistemas de solvente água-etanol sobre as propriedades físico-químicas e espectroscópicas dos compostos macrocíclicos feofitina e clorofila α

This work focus on the influence of solvent on the photophysical properties of chlorophyll α and pheophytin. Both compounds are related to the photosynthesis process and are considered prototypes of photosensitizers in Photodynamic Therapy. Fluorescence measurements were developed using water/ethanol mixtures at different compositions, since both solvents could be employed in biological applications. The spectroscopic properties of these compounds undergo profound changes depending on water content in the ethanol due to auto-aggregation processes. The major hydrophobicity and the lower dielectric constant of ethanol when compared with water precluded significantly the auto-aggregation process of these compounds.

Measuring air pressure with a polymeric gas sensor

In this communication we describe the application of a conductive polymer gas sensor as an air pressure sensor. The device consists of a thin doped poly(4'-hexyloxy-2,5-biphenylene ethylene) (PHBPE) film deposited on an interdigitated metallic electrode. The sensor is cheap, easy to fabricate, lasts for several months, and is suitable for measuring air pressures in the range between 100 and 700 mmHg.