Micro-computed tomographic assessment of dentinal microcrack formation in straight and curved root canals in extracted teeth prepared with hand, rotary and reciprocating instruments.

AIM: To compare microcrack formation in roots of extracted teeth after the shaping of straight and curved root canals with hand, rotary and reciprocating files using micro-computed tomographic (micro-CT) analysis. METHODOLOGY: Thirty straight mandibular incisors and 30 severely curved mesial roots of mandibular molars were randomly divided into 6 experimental groups (n = 10) according to the systems used for the root canal preparation and the root canal curvature: ProTaper Universal for Hand Use (Dentsply Sirona, Ballaigues, Switzerland), HyFlex EDM (Coltene-Whaledent, Altstätten, Switzerland) and Reciproc Blue (VDW, Munich, Germany) files used in mandibular incisors (straight canals) and mesial roots of mandibular molars (curved canals). The roots were imaged with micro-CT scanning at an isotropic resolution of 14 µm before and after root canal preparation, and the cross-sectional images generated were assessed to detect microcracks. RESULTS: All dentinal defects identified after root canal preparation were already present before instrumentation, and no new microcracks were detected. Dentinal microcracks were present in 19% (ProTaper Universal for Hand Use), 11% (Hyflex EDM) and 23% (Reciproc Blue) of the cross-sections when the instrumentation was performed in mandibular incisors. Instrumentation of mandibular molars revealed microcracks in 15% (ProTaper Universal for Hand Use), 16% (Hyflex EDM) and 17% (Reciproc Blue) of the cross-sections. CONCLUSIONS: Preparation of straight and curved root canals with ProTaper Universal for Hand Use, HyFlex EDM and Reciproc Blue systems did not produce microcracks in extracted teeth when evaluated with micro-CT.

Density and Distribution of Xylocopa Nests (Hymenoptera: Apidae) in Caatinga Areas in the Surroundings of Passion Fruit Crops.

Due to their importance as pollinators of many plant species, this study aimed to know the nest density, spatial distribution, and nesting substrates used by Xylocopa species in the Caatinga, a xerophilous vegetation of Northeastern Brazil. Three areas of Caatinga in the surroundings of passion fruit crops were sampled. The bee species found in these areas were Xylocopa grisescens Lepeletier and Xylocopa frontalis (Olivier). All nests were in Commiphora leptophloeos (Burseraceae) trees (n = 113). Phytosociological analysis showed that this tree species presented the highest absolute density (212.5 individuals/ha) and index of importance value (52.7). The distribution pattern of the C. leptophloeos was aggregated. The nests were located in dead and dried branches with an average diameter of 5.3 ± 2.0 cm (n = 43). The mean number of nests/tree was 3.1 ± 2.8 (n = 113). The less disturbed area showed 6.7 nests/ha and 4.2 nests/tree. In the disturbed areas, 0.9 nests/ha and 2.4 to 2.7 nests/tree were observed. The availability of substrate for nesting in the studied areas and its importance as a limiting factor for nesting are discussed.

Mitochondrial DNA variability in populations of Centris aenea (Hymenoptera, Apidae), a crop-pollinating bee in Brazil.

Centris spp are oil-collecting solitary bees that are valuable pollinators of crops such as Brazil nut, cashew, and acerola. We investigated the genetic variability of populations of C. aenea in the northeastern region of Brazil. Total DNA was extracted from 59 individuals from 6 locations in the States of Pernambuco and Bahia and a 600-650-bp fragment of the mitochondrial COI/COII region amplified by PCR, followed by digestion with the restriction enzymes DraI and SspI. PCR-RFLP analysis revealed eight different haplotypes among the populations. Haplotype A1, revealed by DraI, was the most frequent (50%), and haplotypes A3 and A4 were exclusive to Feira de Santana, Bahia and Morro do Chapéu, Bahia, respectively. Among the haplotypes revealed by SspI, B2 was the most frequent (37%) and B3 was exclusive to Feira de Santana. This information revealing high haplotype diversity will be useful for developing management strategies for Centris, especially because of increasing interest in the rearing and/ or relocation of these bees for crop pollination.

Morphometric analysis of populations of Centris aenea Lepeletier (Hymenoptera: Apidae) from Northeastern Brazil.

Centris aenea Lepeletier is a solitary bee that has raised interest in management to pollinate crops, such as acerola, Malpighia emarginata. This study investigated the level of morphometric variability among populations of C. aenea from Northeastern Brazil. Traditional and geometric morphometric analyses were used. Head length, leg length, wing length, and wing shape were measured in samples (5-10 females) from eight localities. We did not find statistically significant differences among the populations (P > 0.01). The partial wing warps were similar in the populations and indicated that the bees were not morphometrically different. Our results suggest that C. aenea shows low population morphometric variability and highlight the need for further investigations on population variation in this species, preferably including populations sampled at the extremes of their geographic distribution. Significant insight into the population variation of C. aenea will probably require the use of molecular markers to allow a comparative approach between morphometric variability and genetic variability.

Fluctuations in richness and abundance of social wasps during the dry and wet seasons in three phyto-physiognomies at the tropical dry forest of Brazil.

The social wasp nests were quantified in three different plant physiognomies (forested Caatinga, shrubby Caatinga, and agricultural systems) to analyze the effect of environmental seasonality and plant physiognomy on the richness, nest abundance, and species composition of social wasps in the region of tropical dry forest of Brazil. The forested Caatinga physiognomy had the greatest richness of species (S = 16), followed by shrubby Caatinga (S = 13) and by agricultural system (S = 12). The first axis of detrended correspondence analysis (DCA) explained 67.8% of the variability and shows a gradient of the fauna from agricultural system and shrubby Caatinga to forested Caatinga. In the first axis, wet season scores were much higher than those for the dry season in forested Caatinga. The second axis explained 18.7% of the variability and shows a separation of samples collected during the wet or the dry periods in shrubby Caatinga. This separation was less evident in the agricultural system. Variations in nest abundance were more intense in arbustive caatinga (45% decrease in number of active nests in the dry period), moderate in forested Caatinga (24% decrease in number of active nests in the dry period), and low in agricultural systems (8% decrease in the dry period).

Type 2 dens invaginatus in a maxillary lateral incisor: a case report of a conventional endodontic treatment.

Dens invaginatus is a rare malformation of the teeth resulting from the invagination of the tooth crown before biological mineralization occurs. In most cases, the thin or incomplete enamel lining of the invagination cannot prevent the entry of bacteria into the pulp, which leads to pulp necrosis with an eventual periapical inflammatory response. The treatment options include preventive sealing or filling of the invagination, root canal treatment, endodontic apical surgery and extraction. The root canal treatment of such teeth is often complicated because of their anatomical complexity. This case describes a successful non-surgical endodontic treatment of a maxillary lateral incisor with type 2 dens invaginatus with a large periradicular lesion. At follow-up examinations after 6 and 12-months, the tooth was asymptomatic and the healed lesion was evident radiographically

The effect of supplementing layer diets with shark cartilage or chitosan on egg components and yolk lipids.

1. An experiment was designed to evaluate the effects of the addition of shark cartilage (SC) or chitosan (CH) to layer diets on egg component weights, yolk lipids and hen plasma lipids. 2. Hy-Line laying hens (80) were used during a 56 d feeding trial. Treatments were: basal diet (BD), BD + 20 g/kg SC, BD + 30 g/kg SC, BD + 20 g/kg CH and BD + 30 g/kg CH. Eggs were analysed on d 14, 28, 42 and 56. 3. Egg weight and egg component weights were not affected by these treatments throughout the experimental period. 4. After 14d of experimental feeding, cholesterol levels were higher in eggs from birds given BD + 20 g/kg CH and BD + 30 g/kg CH than in those from birds given BD. 5. Furthermore, eggs from hens given BD + 20 g/kg SC or BD + 20 g/kg CH were higher in palmitic and stearic acids and lower in oleic acid than those from birds fed on BD. After 56 d feeding, however, palmitic and stearic acid contents in eggs from hens given any of the supplemented diets were lower than in those from hens given BD, and oleic acid in eggs from hens given BD + 20 g/kg SC, BD + 30 g/kg SC and BD + 30 g/kg CH was higher than in those from birds fed on BD. 6. Plasma cholesterol and triacylglycerol levels were not significantly affected by dietary treatment. 7. Shark cartilage or chitosan at up to 30 g/kg in layer diets did not affect egg component weights (yolk, white and shell) and total lipid contents. During the period from 42 to 56d of experimental feeding, diets containing up to 30 g/kg chitosan reduced egg yolk contents of cholesterol, palmitic and stearic acids and increased the content of oleic acid.

Effect of deboning time, muscle tensioning, and calcium chloride marination on texture characteristics of chicken breast meat.

Tenderness is the most important organoleptic characteristic of meat, and various methods have been developed to improve it. The purpose of this experiment was to evaluate the effect of different conditioning treatments of broiler carcasses on pH, cooking losses, shear values, R-values, and sensory tenderness of breast meat. All measurements were collected for breast muscle as follows: after 24 h of carcass aging (T1); after 24 h of carcass aging with muscle tensioning (T2); after 24 h of carcass aging with muscle tensioning, followed by muscle collection and marination in CaCl2 (T3); after hot-boning 15 min following slaughter (T4); after hot-boning 15 min following slaughter and marination in CaCl2 (T5). pH values in meat treated with CaCl2 were significantly lower than those in untreated meat from the aged carcass group (T3) or the hot-boning group (T5). Breasts from carcasses aged for 24 h (T1, T2, and T3) showed lower cooking loss than breasts harvested immediately after slaughter (T4 and T5). CaCl2 marination produced meats with cooking losses significantly higher than those observed for untreated meats. Regardless of muscle tensioning or marination treatments, aging of the carcass for 24 h (T1, T2, and T3) produced meats with lower shear values than those from hot-boned carcasses (T4 and T5). Hot-boned breasts treated with CaCl2 (T5) were judged less tender by panelists than breasts aged under muscle tensioning (T2 and T3).