Effect of staining agents on color change of composites

Composite resins are materials that can present color changing when exposed to pigments. Objective: The aim of this study was to evaluate, in vitro, the color changing of composites after immersion in different substances for different periods. Material and methods: Two microhybrid composite resins: Charisma (Heraeus – Kulzer) and Opallis (FGM) were used. Red wine and acai pulp were also used as immersion medium. For this study, 32 specimens with 10 mm of diameter and 2 mm of thickness were used, divided into 4 groups: Group 1 – Opallis composite immersed in red wine solution; Group 2 – Opallis composite immersed in acai berry pulp solution; Group 3 – Charisma composite immersed in red wine solution; Group 4 – Charisma composite immersed in acai berry pulp solution. The specimens were evaluated in the following time periods: T0 – baseline, T1 – 24 hours, T2 – 48 hours, T3 – 72 hours and T4 – 96 hours. For the assessment of staining, a spectrophotometer for colorimetry was used (Color Guide 45 / 0, PCB 6807 BYK-Gardner Gerestsried GmBH, Germany), and the values obtained were transferred to a computer and recorded according to CIELAB system. Results: The data were evaluated using Kruskal- Wallis non-parametric tests with the following mean values for the immersion periods of 24, 48, 72 and 96 hours, respectively: G1 – 7.35, 7.84, 9.04,10.48; G2 – 2.92, 4.15, 4.30, 4.64; G3 – 3.14, 7.35, 8.13, 8.43, G4 – 4.49, 5.99, 6.92, 6.76. Conclusion: Red wine showed a higher tendency toward altering the composite color than acai berry pulp. In addition, no significant difference was found concerning to the behavior of the two composite resins. Concerning to the immersion time periods, significant differences were only observed among the groups in the 24 hour time period.

Evaluation of Radiopacity, pH, Release of Calcium Ions, and Flow of a Bioceramic Root Canal Sealer

Introduction: The aim of the present study was to evaluate the physicochemical properties of a bioceramic root canal sealer, Endosequence BC Sealer. Radiopacity, pH, release of calcium ions (Ca2+), and flow were analyzed, and the results were compared with AH Plus cement. Methods: Radiopacity and flow were evaluated according to ISO 6876/2001 standards. For the radiopacity analysis, metallic rings with 10-mm diameter and 1-mm thickness were filled with cements. The radiopacity value was determined according to radiographic density (mm Al). The flow test was performed with 0.05 mL of cement placed on a glass plate. A 120-g weight was carefully placed over the cement. The largest and smallest diameters of the disks formed were measured by using a digital caliper. The release of Ca2+ and pH were measured at periods of 3, 24, 72, 168, and 240 hours with spectrophotometer and pH meter, respectively. Data were analyzed by analysis of variance and Tukey test (P < .05). Results: The bioceramic endodontic cement showed radiopacity (3.84 mm Al) significantly lower than that of AH Plus (6.90 mm Al). The pH analysis showed that Endosequence BC Sealer showed pH and release of Ca2+ greater than those of AH Plus (P < .05) during the experimental periods. The flow test revealed that BC Sealer and AH Plus presented flow of 26.96 mm and 21.17 mm, respectively (P < .05). Conclusions: Endosequence BC Sealer showed radiopacity and flow according to ISO 6876/2001 recommendations. The other physicochemical properties analyzed demonstrated favorable values for a root canal sealer. (J Endod 2012;38:842-845)

MODELING OF WEEDS INTERFERENCE PERIODS IN BEAN

The research objective was to determine the effects of spacing and seeding density of common bean to the period prior to weed interference (PPI) and weed period prior to economic loss (WEEPPEL). The treatments consisted of periods of coexistence between culture and the weeds, with 0 to 10, 0 to 20, 0 to 30, 0 to 40, 0 to 50, 0 to 60, 0 to 70, and 0 to 80 days and a control maintained without weeds. In addition to the periods of coexistence, there were still studies with an inter-row of 0.45 and 0.60 m, 10 and 15 plants m(-1). The experimental delineation used was randomized blocks with four repetitions per treatment. The grain productivity of the culture had a reduction of 63, 50, 42 and 57% when the coexistence with the weed plants was during the entire cycle of the culture for a row spacing of 0.45 m and a seeding density of 10 and 15 plants per meter; and a row spacing of 0.60m and a seeding density of 10 and 15 plants per meter, respectively. The PPI occurred in 23, 27, 13, and 19 days after crop emergence and WEEPPEL in 10, 9, 8, and 8 days, respectively.

WEAR OF MATRIX OVERDENTURE ATTACHMENTS AFTER ONE TO EIGHT YEARS OF CLINICAL USE

Statement of problem. Matrices of unsplinted attachment systems are generally reported to be the weak component of implant overdentures, often requiring frequent maintenance. Clinical wear results in reduced retention of the prosthesis, requiring activation or renewal of the matrix to restore the initial level of retention. Purpose. The purpose of this retrospective study was to measure the wear of the matrix of a ball attachment after various periods of clinical wear. Material and methods. Seventy specimens of 3 groups of matrices of ball attachments that had been in use for mean periods of 12.3 months (1Y group, n=26), 39.0 months (3Y group, n=28) and 95.6 months (8Y group, n=16) were retrieved from 35 patients (2 specimens per patient) and measured on a coordinate measuring machine equipped with a touch trigger probe. Ten unused matrices were used as controls (CTRL group). The external and internal matrix diameters and deviations from circularity were measured. For the various time periods, the decreases in matrix thickness were calculated and compared with controls. Kruskal-Wallis 1-way ANOVA by ranks, followed by the Mann-Whitney post hoc tests, were conducted to test for differences in median values among groups (alpha=.05). Results. For the internal upper diameter of the matrices tested, the Kruskal-Wallis and Mann-Whitney tests revealed significant differences for the 3 groups compared to the controls. For group 1Y, a significant difference (P<.001) of the internal upper diameter was found compared to the CTRL group. Compared to the controls, the nonparametric analyses for groups 3Y and 8Y showed significant differences for the internal upper diameter (P<.001) and deviations from circularity (P<.001). For groups 1Y, 3Y and 8Y, matrix thickness losses were 07, 47 and 70 pm, respectively. Conclusions. Within the limitations of this study, it was observed that one year of clinical wear had limited effect on the ball attachment matrices. Three to 8 years of clinical use resulted in a significant decrease of matrix thickness, especially at the tip of the retentive lamellae. (J Prosthet Dent 2012;107:191-198)

Digestion of feed fractions and intake of heifers fed hydrolyzed sugarcane stored for different periods

The objective of this study was to evaluate, in Nellore heifers, intake and digestibility of hydrolyzed sugarcane stored for different periods. The experimental design used was a 4 × 4 Latin square, four diets, four Nellore heifers with ruminal cannulas (initial body weight 285.4±23.08 kg and average initial age 14 months) and four periods of 21 days. The diets were composed by fresh sugarcane (time zero) or hydrolyzed sugarcane with addition of 0.5% of hydrated lime, stored for 24, 48 or 72 hours, as the unique forage. Intake and digestibility of feed fractions, nitrogen balance, microbial synthesis efficiency, total number of ruminal protozoans and ammoniacal nitrogen did not significantly change by storing sugarcane with addition of 0.5% of hydrated lime. Sugarcane pH varied quadratically for storage time, with maximum pH of 7.02 after 24 hours from lime addition. Ruminal liquid pH values were higher for heifers fed fresh sugarcane, in comparison with those fed hydrolyzed sugarcane. Sugarcane treated with 0.5% of hydrated lime stored for up to 72 hours does not change ruminal digestion to alter the amount of feed consumed by pubescent Nellore heifers. Thus, lime is a viable technology, once it allows long-duration storage and bee control on treated forage, which contributes to animal feeding logistics.

In vivo measurement of central corneal thickness in normal chicks (Gallus gallus domesticus) with the optical low-coherence reflectometer

OBJECTIVE To determine the practicability and accuracy of central corneal thickness (CCT) measurements in living chicks utilizing a noncontact, high-speed optical low-coherence reflectometer (OLCR) mounted on a slit lamp. ANIMALS STUDIED Twelve male chicks (Gallus gallus domesticus). Procedures  Measurements of CCT were obtained in triplicate in 24 eyes of twelve 1-day-old anaesthetized chicks using OLCR. Every single measurement taken by OLCR consisted of the average result of 20 scans obtained within seconds. Additionally, corneal thickness was determined histologically after immersion fixation in Karnovsky's solution alone (20 eyes) or with a previous injection of the fixative into the anterior chamber before enucleation (4 eyes). RESULTS Central corneal thickness measurements using OLCR in 1-day-old living chicks provide a rapid and feasible examination technique. Mean CCT measured with OLCR (189.7 ± 3.34 μm) was significantly lower than histological measurements (242.1 ± 47.27 μm) in eyes with fixation in Karnovsky's solution (P = 0.0005). In eyes with additional injection of Karnovsky's fixative into the anterior chamber, mean histologically determined CCT was 195.2 ± 8.25 μm vs. 191.9 ± 8.90 μm with OLCR. A trend for a lower variance was found compared to the eyes that had only been immersion fixed. CONCLUSION Optical low-coherence reflectometry is an accurate examination technique to measure in vivo CCT in the eye of newborn chicks. The knowledge of the thickness of the chick cornea and the ability to obtain noninvasive, noncontact measurements of CCT in the living animal may be of interest for research and development of eye diseases in chick models.

Effects of Initial Fat Thickness, Hip Height, and Concentration of Dietary Energy on Growth of Area of the Longissimus dorsi Muscle and Subcutaneous Fat of Yearling Steers

Steers were sorted into four groups based on hip height and fat cover at the start of the finishing period. Each group of sorted steers was fed diets containing 0.59 or 0.64 Mcal NEg per lb. of diet dry matter. Steers with less initial fat cover (0.08 in.) compared with those with more (0.17) had less carcass fat cover 103 days later. The steers with less fat cover accumulated fat at a faster rate, but this was not apparent prior to 80 days. Accretion of fat was best predicted by an exponential growth equation, and was not affected by the two concentrations of energy fed in this study. Steers with greater initial height accumulated fat cover at a slower rate than shorter steers. This difference was interpreted to mean that large-frame steers accumulate subcutaneous fat at a slower rate than medium-frame steers. Increase in area of the ribeye was best described by a linear equation. Initial fat cover, hip height, and concentrations of energy in the diet did not affect rate of growth of this muscle. Predicting carcass fat cover from the initial ultrasound measurement of fat thickness found 46 of the 51 carcasses with less than 0.4 in. of fat cover. Twelve carcasses predicted to have less than 0.4 in. of fat cover had more than 0.4 in. Five carcasses predicted to have more than 0.4 in. actually had less than that. Accurate initial measurements of initial fat thickness with ultrasound might be a useful measurement to sort cattle for specific marketing grids.

Increment thickness versus dentin bond strength of bulk fill flowables

Objectives: The aim was to investigate the influence of increment thickness on shear bond strength (SBS) to dentin of a conventional and two bulk fill flowable composites. Methods: A total of 135 specimens of ground human dentin were produced (n=15/group; 3 increment thicknesses; 3 flowable composites) and the dentin surfaces were treated with the adhesive system OptiBond FL (Kerr) according to manufacturer’s instructions. Split Teflon molds (inner diameter: 3.6 mm) of 2 mm, 4 mm, or 6 mm height allowing three increment thicknesses were clamped on the dentin surfaces and filled with either the conventional flowable Filtek Supreme XTE ((XTE); 3M ESPE) or the bulk fill flowables Filtek Bulk Fill ((FBF); 3M ESPE) or SDR ((SDR); DENTSPLY Caulk). The flowable composites were light-cured for 20 s (Demi LED; Kerr) and the specimens stored for 24 h (37°C, 100% humidity). Specimens were then subjected to a SBS-test in a universal testing machine at a cross-head speed of 1 mm/min (Zwick Z010; Zwick GmbH & Co.). SBS-values were statistically analysed with a nonparametrical ANOVA followed by exact Wilcoxon rank sum tests (α=0.05). Failure mode of the specimens was determined under a stereomicroscope at 25× magnification. Results: SBS-values (MPa) at 2 mm/4 mm/6 mm increment thicknesses (mean value [standard deviation]) were for XTE: 18.8 [2.6]/17.6 [1.6]/16.7 [3.1], for FBF: 20.6 [2.7]/17.8 [2.7]/18.7 [2.9], and for SDR: 21.7 [2.6]/18.5 [2.6]/20.3 [3.0]. For all three flowable composites, 2 mm increments yielded the highest SBS-values whereas for increments of 4 mm and 6 mm no differences were detected. All specimens presented failure modes involving cohesive failure in dentin. Conclusion: The influence of increment thickness on dentin SBS was less pronounced than expected. However, the high number of cohesive failures in dentin, reflecting the efficiency of the adhesive system, suggests a limited discriminatory power of the SBS-test.

Bone loss after ridge expansion with or without reflection of the periosteum.

OBJECTIVE To evaluate the role of the periosteum in preserving the buccal bone after ridge splitting and expansion with simultaneous implant placement. MATERIAL AND METHODS In 12 miniature pigs, the mandibular premolars and first molars were removed together with the interdental bone septa and the buccal bone. Three months later, ridge splitting and expansion of the buccal plate was performed with simultaneous placement of two titanium implants per quadrant. Access by a mucosal flap (MF) was prepared on test sides, while a mucoperiosteal flap (MPF) with complete denudation of the buccal bone was increased on control sides. After healing periods of six and 12 weeks, the animals were sacrificed for histologic and histometric evaluation. RESULTS In the MF group, all 16 implants were osseointegrated, while in the MPF group, four of 16 implants were lost. Noticeable differences of bone levels on the implant surface and of the bone crest (BC) were found between the MF and the MPF group. Buccally after 6 weeks, the median distance between the implant shoulder (IS) and the coronal-most bone on the implant (cBIC) was for the MF group -1.42 ± 0.42 mm and for the MPF group -4.80 ± 2.72 mm (P = 0.15). The median distance between the IS and the buccal BC was -1.24 ± 0.51 mm and -2.78 ± 1.98 mm (P = 0.12) for the MF and MPF group, respectively. After 12 weeks, median IS-cBIC was -2.12 ± 0.84 mm for MF and -7.19 mm for MPF, while IS-BC was -2.08 ± 0.79 mm for MF and -5.96 mm for MPF. After 6 weeks, the median buccal bone thickness for MF and MPF was 0.01 and 0 mm (P < 0.001) at IS, 1.48 ± 0.97 mm and 0 ± 0.77 mm (P = 0.07) at 2 mm apical to IS, and 2.12 ± 1.19 mm and 1.72 ± 01.50 mm (P = 0.86) at 4 mm apical to IS, respectively. After 12 weeks, buccal bone thickness in the MF group was 0 mm at IS, 0.21 mm at 2 mm apical to IS, and 2.56 mm at 4 mm apical to IS, whereas complete loss of buccal bone was measured from IS to 4 mm apical to IS for the MPF group. CONCLUSIONS In this ridge expansion model in miniature pigs, buccal bone volume was significantly better preserved when the periosteum remained attached to the bone.

Human–climate interactions in the central Mediterranean region during the last millennia: The laminated record of Lake Butrint (Albania)

Lake Butrint (39°47 N, 20°1 E) is a ca. 21 m deep, coastal lagoon located in SW Albania where finely-laminated sediments have been continuously deposited during the last millennia. The multi-proxy analysis (sedimentology, high-resolution elemental geochemistry and pollen) of a 12 m long sediment core, supported by seven AMS radiocarbon dates and 137Cs dating, enable a precise reconstruction of the environmental change that occurred in the central Mediterranean region during the last ∼4.5 cal kyrs BP. Sediments consist of triplets of authigenic carbonates, organic matter and clayey laminae. Fluctuations in the thickness and/or presence of these different types of seasonal laminae indicate variations in water salinity, organic productivity and runoff in the lake's catchment, as a result of the complex interplay of tectonics, anthropogenic forcing and climate variability. The progradation of the Pavllo river delta, favoured by variable human activity from the nearby ancient city of Butrint, led to the progressive isolation of this hydrological system from the Ionian Sea. The system evolved from an open bay to a restricted lagoon, which is consistent with archaeological data. An abrupt increase in mass-wasting activity between 1515 and 1450 BC, likely caused by nearby seismic activity, led to the accumulation of 24 homogenites, up to 17 cm thick. They have been deposited during the onset of finely laminated sedimentation, which indicates restricted, anoxic bottom water conditions and higher salinity. Periods of maximum water salinity, biological productivity, and carbonate precipitation coincide with warmer intervals, such as the early Roman Warm Period (RWP) (500 BC–0 AD), the Medieval Climate Anomaly (MCA) (800–1400 AD) and recent times (after 1800 AD). Conversely, lower salinity and more oxic conditions, with higher clastic input were recorded during 1400–500 BC, the Late Roman and the Early Medieval periods (0–800 AD) and during the Little Ice Age (1400–1800 AD). Hydrological fluctuations recorded in Butrint are in phase with most central and western Mediterranean records and correlate with NAO variability. In contrast, opposite hydrological patterns have been recorded in the Eastern Balkans and the Levant during the last millennium, emphasizing a complex spatial variability in the region. Phases of maximum settlement intensity in Butrint (Roman-Late Antique) coincide with warmer and/or stable climate periods (0–800 AD and MCA, respectively), indicating a long-term influence of climatic conditions on human activities. The Late Holocene sedimentary record of Lake Butrint demonstrates the complex interplay of climate variability, tectonics and human impact in the recent evolution of coastal Mediterranean regions.

Tab. 2: Grain-sizes of cobble on the surface of sanderwurzel

yResults of 13 field investigations between 1966 and 1990 of the southwestern to eastern margin of Kötlujökull and its proglacial area are summarized with respect to sandar and their formation. Generally, the results are based on sedimentological examinations in the field and laboratory, on analyses of aerial photographs, and investigations of the glacier slope. The methods permitted a more detailed reconstruction of sandar evolution in the proglacial area of Kötlujökull since 1945, of tendencies in development and of single data going back until the last decades of the 19th century. Accordingly, there existed special periods of "flachsander"-formations with raised coarsegrained "sanderwurzels" resultant from the outbreak of subglacial meltwater tunneloutlets and other periods with "hochsander-"formations by supraglacial drainage. At present the belts of hochsanders in front of the glacier come up to more than 4 m in thickness and 1000 m in width, therefore containing perhaps more sediment direct in front of Kötlujökull than the old belts of flachsanderwurzels. In one case the explosion-like subglacial meltwater outburst combined with the genesis of a sanderwurzel could be observed for a time and is thoroughly discussed. The event is referred to the outburst of a sub- to inglacial meltwater body being under extreme hydrostatic press ures which is combined with the genesis of a new subglacial tunneloutlet as a new flachsander. Often these outbursts led to the destruction of a morainic belt more than 1000 m in width. Presumably the whole event was finished in not more than a few days. In addition to a characteristic pear-shaped form and water-moved stones up to diameters of 1 m the wurzels possess a single "main-channel" with rectangular cross-sections as far as 4 m deep and 50 m wide just as small flat channels resembling fish bones in connection with the main channel. Presumably, they have been active only in the last stage of wurzel formation. With regard to the subglacial tunnel gates long-living L-meltwater outlets are distinguished from short-living K-meltwater outlets. These are always combined with a raised coarse-grained sanderwurzel, but its meltwater discharge is generally decreasing and ceases after some years, whereas the discharge of L-meltwater outlets continues unchanged for long times (except seasonal differences). The material of flachsanders is preponderantly composed of mugearitic and andesitic cobble extending at least for some kilometres from the glacier margin, whereas the hochsanders correspond to medium to coarse sands without clay and without alternations into the direction of flow. The hochsander fans are covered with small braidet channels. Their sedimentary structures are determined by the short time changing of supraglacial meltwater discharge and the upper flow regime combined with the development of antidunes, which rule the channel-flows during the main activity periods in summer. Unlike the subglacial drainage the supraglacial drainage led to only weak effects of erosion on the glacier foreland. So the hochsanders refilled depressions of morainic areas or grew up on older flachsanderwurzels. Whereas all large flachsanders developed in front of approximate stationary glacier margins, the evolution of coherent belts of hochsanders were combined with progressive glacier fronts. On the other hand, there was obviously no evolution at all of large sandar in front of back-melting margins of Kötlujökull. Based on examinations of the glacier surface and on analyses of aerial photographs the different types of sandar are referred to different structures of the glacier snout. Finally chances of surviving of sandar in the proglacial area of Kötlujökull are shortly discussed just as the possibility of an application of the Islandic research results on Pleistocene sandar in northern Germany.

Calcareous nannofossils of ODP Hole 123-765C and DSDP Hole 27-261

Sediments from the Argo Abyssal Plain (AAP), northwest of Australia, are the oldest known from the Indian Ocean and were recovered from ODP Site 765 and DSDP Site 261. New biostratigraphic and sedimentologic data from these sites, as well as reinterpretations of earlier findings, indicate that basal sediments at both localities are of Late Jurassic age and delineate a history of starved sedimentation punctuated by periodic influx of calcareous pelagic turbidites. Biostratigraphy and correlation of Upper Jurassic-Lower Cretaceous sediments is based largely on calcareous nannofossils. Both sites yielded variably preserved nannofossil successions ranging from Tithonian to Hauterivian at Site 765 and Kimmeridgian to Hauterivian at Site 261. The nannofloras are comparable to those present in the European and Atlantic Boreal and Tethyan areas, but display important differences that reflect biogeographic differentiation. The Argo region is thought to have occupied a position at the southern limit of the Tethyan nannofloral realm, thus yielding both Tethyan and Austral biogeographic features. Sedimentary successions at the two sites are grossly similar, and differences largely reflect Site 765's greater proximity to the continental margin. Jurassic sediments were deposited at rates of about 2 m/m.y. near the carbonate compensation depth (CCD) and contain winnowed concentrations of inoceramid prisms and nannofossils, redeposited layers rich in calcispheres and calcisphere debris, manganese nodules, and volcanic detritus. Lower Cretaceous and all younger sediments accumulated below the CCD at rates that were highest (about 20 m/m.y.) during mid-Cretaceous and Neogene time. Background sediment in this interval is noncalcareous claystone; turbidites dominate the sequence and are thicker and coarser grained at Site 765. AAP turbidites consist mostly of calcareous and siliceous biogenic components and volcanogenic smectite clay; they were derived from relatively deep parts of the continental margin that lay below the photic zone, but above the CCD. The Jurassic-Lower Cretaceous section is about the same thickness across the AAP; turbidites in this interval appear to have had multiple sources along the Australian margin. The Upper Cretaceous-Cenozoic section, however, is three times thicker at Site 765 than at Site 261; turbidites in this interval were derived predominantly from the south. Patterns of sedimentation across the AAP have been influenced by shifts in sea level, the CCD, and configuration of the continental margin. Major pulses of calcareous turbidite deposition occurred during Valanginian, Aptian, and Neogene time-all periods of eustatic lowstands and depressed CCD levels. Sediment redeposited on the AAP has come largely from the Australian outer shelf, continental slope, or rise, rather than the continent itself. Most terrigenous detritus was trapped in epicontinental basins that have flanked northwestern Australia since the early Mesozoic.