Screw removal torque evaluation in implants with cone morse and external hexagon platforms in anterior cantilever

This study aims to evaluate the screw removal torque on prosthetic platforms of Cone Morse (CM) and External Hexagon (EH) implants in crowns with anterior cantilever. Materials and Methods: in vitro study with a sample consisting of 20 test specimens of 2 elements (21 and 22), with n = 40; load is simulated on element 21 or on cantilever of 22. Samples were divided into 4 groups consisting of 10 test specimens on CM implants (groups 1 and 2), and 10 test specimens on EH implants (groups 3 and 4). The test specimens were manufactured using cylindrical PVC pipes measuring 22 x 19.05 mm filled with acrylic resin. The implants were fixed with a centralization device. Components used were EUCLAs and UCLAs with a chrome-cobalt alloy molten base. The metal bases were scanned, the crowns were digitally waxed, made on CAD/CAM system, and cemented on the metal bases with Panavia cement. Torque was applied using 20N for CM and 32N for EH, according to the manufacturers’ instructions. The test specimens were then subjected to a cycling process consisting of 1,000,000 cycles at a frequency of 2 Hz. The cyclic process applied axial forces to the surface (palate face of 21 and 22). Two cycling processes were carried on, the first on the palate face of 21 and the second on the palate face of 22. Between the two, screws were removed and replaced by new ones. The screw removal torque was measured using a digital torque meter. Results were analyzed with Student’s t test and variance analysis. Statistical calculations were conducted in SPSS 23 using 5% of significance. Results: Student’s t test showed significantly lower removal torque values in comparison with initial torque for both CM and EH connection implants and force applied to elements 21 and 22 (p < 0.001) or 22 (p < 0.001). Considering torque loss, there was no significant effect of the interaction between type of implant connection and site of force application (p = 0.094). Removal torque was significantly lower than initial torque for both implants (CM and EH). Conclusion: Torque loss occurred both in CM and EH. There was no significant effect of the interaction between connections and site of force application.

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Effectiveness and efficiency of chemomechanical carious dentin removal

Brazilian Dental Journal ◽

10.1590/s0103-64402006000100014 ◽

2006 ◽

Vol 17 (1) ◽

pp. 63-67 ◽

Cited By ~ 12

Author(s):

Cláudia Silami de Magalhães ◽

Allyson Nogueira Moreira ◽

Wagner Reis da Costa Campos ◽

Fernanda Magalhães Rossi ◽

Guilherme Augusto Alcaraz Castilho ◽

...

Keyword(s):

In Vitro Study ◽

Knoop Hardness ◽

T Test ◽

Carious Lesions ◽

Efficiency And Effectiveness ◽

Effectiveness And Efficiency ◽

Student’S T ◽

Cavity Floor ◽

Student’S T Test

The aims of this in vitro study were both to determine the time necessary for removal of carious dentin (efficiency) and the Knoop Hardness Number (KHN) of the remaining dentin (effectiveness), using a chemomechanical method (Carisolv) or hand excavation. Thirty human molars were bisected through occlusal carious lesions into two equal halves. Each half was randomly excavated by hand in circular movements with a spoon excavator or using Carisolv gel according to the manufacturer's instructions. The duration of carious dentin removal was recorded. Tooth sections were resin-embedded, ground flat and polished. Dentin KHN was determined at distances of 100, 200, 300, 400 and 500 mum from the cavity floor. Data were analyzed by Wilcoxon's test (alpha=0.01), ANOVA and Student's t test (alpha= 0.05). The median of the time necessary for chemomechanical excavation was significantly greater than for hand excavation. KHN means (± SD) at 100, 200, 300, 400, 500 µm for chemomechanical method were, respectively: 15.6 (±4.96), 18.0 (±6.22), 21.3 (±9.30), 24.3 (±9.25), 28.5 (±11.80); and for hand excavation were: 21.2 (±10.26), 23.4 (±9.49), 28.2 (±11.62), 31.0 (±12.17), 34.3 (±11.95). It may be concluded that hand excavation presented higher efficiency and effectiveness than chemomechanical excavation.

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Inhibition of Demineralization at Restoration Margins of Z100 and Tetric EvoCeram Bulk Fill in Dentin and Enamel

Bioengineering ◽

10.3390/bioengineering6020036 ◽

2019 ◽

Vol 6 (2) ◽

pp. 36

Author(s):

Cristina Leon-Pineda ◽

Kevin Donly

Keyword(s):

Light Microscopy ◽

Polarized Light ◽

In Vitro Study ◽

The Other ◽

Solution Ph ◽

Class V ◽

The Mean ◽

Student’S T ◽

Student’S T Test

Recurrent caries is still considered the main reason restorations need to be replaced. There are different materials available now that promise to reduce the possibility of recurrent caries by releasing fluoride and inhibiting restoration marginal caries. The purpose of this in vitro study was to evaluate the demineralization inhibition potential of a non-fluoride-releasing resin (Z100TM 3M, St. Paul, MN, USA) and a glass containing resin-based composite (Tetric EvoCeram Bulk Fill, Ivoclar/Vivadent AG, Schaan, Liechtenstein), which contains fluoride. Class V preparations were placed on 22 premolars; the gingival margin was below the cementoenamel junction and the occlusal margin was placed above the cemento-enamel junction. Ten teeth were randomly selected to be restored with Z100 while the other 10 were restored with Tetric EvoCeram Bulk Fill. Both groups were restored following manufacturer’s instructions. All teeth had an acid resistant varnish placed within one millimeter of the preparation margins. Both groups were placed in artificial caries challenge solution (pH 4.4). At the end of the 4 days; 100 µm buccolingual sections were obtained for each tooth; these were photographed under polarized light microscopy and the demineralized areas adjacent to the restorations were measured and quantified. The mean (±S.D.) area (µm2) of demineralization from the occlusal margin (enamel) and dentin margin were: Z100 2781.889 ± 1045.213; 3960.455 ± 705.964 and for Tetric EvoCeram Bulk Fill 1541.545 ± 1167.027; 3027.600 ± 512.078. Student’s t-test indicated that there was significantly less enamel and dentin demineralization adjacent to Tetric EvoCeram Bulk Fill compared to Z100; there was significantly less demineralization in enamel compared to dentin in both Tetric EvoCeral Bulk Fill and Z100. Tetric EvoCeram Bulk Fill performed better inhibiting demineralization at restoration margins when compared to Z100 and provided better demineralization inhibition in enamel than cementum/dentin.

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18 EMBRYO AGGREGATION IN PIG IMPROVES CLONING EFFICIENCY AND EMBRYO QUALITY

Reproduction Fertility and Development ◽

10.1071/rdv28n2ab18 ◽

2016 ◽

Vol 28 (2) ◽

pp. 139

Author(s):

C. Buemo ◽

A. Gambini ◽

L. Moro ◽

R. F. Y. Martin ◽

D. Salamone

Keyword(s):

In Vitro Culture ◽

Dna Fragmentation ◽

Embryo Development ◽

Embryo Quality ◽

T Test ◽

Control Group ◽

Reconstructed Embryo ◽

Student’S T ◽

Student’S T Test

In this study, we analysed the effects of the cloned embryo aggregation on in vitro embryo development and embryo quality by measuring blastocyst size and cell number, DNA fragmentation levels by TUNEL assay, and the relative expression of genes associated with pluripotency, apoptosis, trophoblast markers, and DNA methylation in the porcine. Cumulus-oocyte complexes were recovered from slaughterhouse ovaries by follicular aspiration. Maturation was performed in TCM for 42 to 48 h at 39°C and 5% CO2. After denudation by treatment with hyaluronidase, mature oocytes were stripped of the zona pellucida using a protease and then enucleated by micromanipulation; staining was performed with Hoëchst 33342 to observe metaphase II. Ooplasms were placed in phytohemagglutinin to permit different membranes to adhere between each other; the ooplasm membrane was adhered to a porcine fetal fibroblast from an in vitro culture. Adhered membranes of the donor cell nucleus and enucleated oocyte cytoplasm were electrofused through the use of an electric pulse (80 V for 30 μs). All reconstituted embryos were electrically activated using an electroporator in activation medium (0.3 M mannitol, 1.0 mM CaCl2, 0.1 mM MgCl2, and 0.01% polyvinyl alcohol) by a DC pulse of 1.2 kVcm for 80 μs. Then, embryos were incubated in 2 mM 6-DMAP for 3 h. In vitro culture of zona-free embryos was achieved in a well of wells system in 100 μL of SOF medium. Two experimental groups were used, one control group with a single reconstructed embryo per microwell (1×) and the other group placing 3 reconstructed embryo per microwell (3x aggregation group). Embryos were cultivated at 39°C in 5% O2, 5% CO2 for 7 days in SOF medium with a supplement of 10% fetal bovine serum on the fifth day. At Day 7, resulting blastocysts were classified according to their morphology and diameter to determine their quality. Our results showed that aggregation of 3× embryos increased blastocyst formation rate and blastocyst size of pig cloned embryos (Fisher’s test P < 0.05 and Student’s t-test P < 0.05, respectively). The DNA fragmentation levels in 3× aggregated cloned blastocysts were significantly decreased compared to 1x blastocyst (Student’s t-test P < 0.05). Levels of Oct4, Klf4, Igf2, Bax, and Dnmt1 transcripts were significantly higher in aggregated embryos, whereas Nanog levels were not affected. Transcripts of Cdx2 and Bcl-xl were essentially nondetectable (Student’s t-test P < 0.05). Our study suggests that embryo aggregation in the porcine may be beneficial for cloned embryo development and embryo quality, through a reduction in apoptotic levels and an improvement in cell reprogramming.

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26 Drugs that Modify Epigenetics...What do they do to Porcine Clones?

Reproduction Fertility and Development ◽

10.1071/rdv30n1ab26 ◽

2018 ◽

Vol 30 (1) ◽

pp. 152

Author(s):

C. P. Buemo ◽

A. Gambini ◽

L. N. Moro ◽

N. Canel ◽

D. F. Salamone

Keyword(s):

Gene Expression ◽

Dna Methylation ◽

Electric Pulse ◽

Donor Cell ◽

T Test ◽

Control Group ◽

Developmental Rates ◽

Student’S T ◽

Student’S T Test

Although somatic cell nuclear transfer (SCNT) technology was developed more than 20 years ago, cloning efficiency remains low. Failures in the reprogramming of the donor cell result in embryos with aberrant epigenetic patterns and low developmental rates. In this study, we assessed whether the use the inhibitor of DNA (cytosine 5) methyltransferase 5-azacitidine (5Aza) combined with the MEK inhibitor in the MAPK pathway PD0325901 (PD) could improve SCNT efficiency in pigs. In vitro maturation of cumulus–oocyte complexes was performed in TCM for 44 h at 39°C under 5% CO2. Cumulus cells and zona pellucida was removed from matured oocytes, followed by enucleation of the metaphase plate previously stained with Hoëchst 33342. Each enucleated oocyte was attached to a donor cell by phytohemagglutinin treatment followed by an electric pulse of 80V for 30 μs. After fusion, reconstituted embryos were activated by an electric pulse followed by an incubation in 2 mM 6-DMAP for 3 h. Cloned embryos were cultured in vitro in a modified well-of-well system in SOF medium, where 3 cloned embryos were placed per microwell (3X). The experimental group 3X + drugs was exposed for the first 3 days to 1 μM PD and 1 μM 5Aza in SOF medium. After washing, embryos were cultured until Day 7 in regular SOF medium. The control group (3X) was cultured in regular SOF medium for 7 days. In vitro embryo developmental rates, gene expression, histone acetylation, and DNA methylation status were studied. The use of epigenetic modifying drugs significantly increased blastocyst rates (40.9% v. 29%; Fisher’s test, P < 0.05) and embryo size (41.46% v. 28.56%; Student’s t-test, P < 0.05) compared with the control group. Regarding gene expression, an increase of the relative expression of genes related to cell differentiation (Igf2 and Cdx2), antiapoptotic pathways (Bcl-xl) and DNA methylation modulation (Mapk1) was observed (P < 0.05). Pluripotency genes Oct4 and Nanog did not show differences between groups. The Bax proapoptotic gene significantly decreased its expression after drug treatment, as did the Klf4 gene (P < 0.05). Results were analysed by Student’s t-test. According to Histone H3K27ac, which is associated with enhancers or gene promoters, its marker was located mainly in the nuclear periphery respect to the control group with a uniform dispersion, indicating that the treatment could be activating certain genes by locating them near the periphery. Histone H3K4me1 was more uniformly localised throughout the nucleus in both groups. The intensity of the fluorescence was measured by quantitative confocal microscopy using a histogram produced by the ImageJ program (National Institutes of Health, Bethesda, MD, USA). Regarding DNA methylation by bisulphite sequencing, the 2 genes studied (Oct4 and DNMT1) showed a higher demethylation status for the treated group. Our results indicate that the combination of 5Aza+PD during early pre-implantation development dramatically increase blastocyst rates and embryo quality. This novel combination could be used as a strategy to improve the efficiency of SCNT in pigs and potentially other animals.

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In vitro study of marginal, internal and proximal adaptation of implant-supported single-crown CAD/CAM restorations

Brazilian Journal of Oral Sciences ◽

10.20396/bjos.v19i0.8657286 ◽

2020 ◽

Vol 19 ◽

pp. e207286

Author(s):

Kamila Aguiar Figueiredo Alves ◽

Janaina Emanuela Damasceno ◽

Viviane Maia Barreto de Oliveira ◽

Luiz Gustavo Cavalcanti Bastos ◽

Andrea Nóbrega Cavalcanti

Keyword(s):

Repeated Measures ◽

T Test ◽

Digital Impression ◽

Single Crown ◽

Significant Difference ◽

Cad Cam ◽

Student’S T ◽

One Way Anova ◽

Student’S T Test

Aim: This study evaluated the precision of a CAD/CAM system by measuring marginal, internal and proximal fits in implantsupported single-crown restorations. Methods: Ten models of the upper arch were made in which implants replaced the upper left premolars. For fabrication of the zirconia infrastructures, titanium bases (TiBase) were coded and scanned using a scan body. A second digital impression was made for the fabrication of prostheses. Silicone impression material was used to determine the internal clearance between the TiBase and infrastructure and between the infrastructure and crown, whose thickness was measured at three points [P1 (cervical), P2 (middle) and P3 (occlusal)] with a stereoscopic microscope at 70x and 100x magnification. One-way ANOVA for repeated measures and the Student t-test were used for the analysis of internal and marginal adaptation. Proximal contacts were analyzed qualitatively. Results: There was no significant difference between the teeth evaluated (Student’s t-test; p>0.05) or between the corresponding points evaluated in either tooth (one-way ANOVA; p>0.05). Analysis of the internal clearance between the infrastructure and crown demonstrated that all points were significantly different compared to the reference standardized at 100 μm (Student’s t-test p<0.0001). There was no significant difference between P1 and P2, with the thickness at these two points being lower than that obtained at P3 (one-way ANOVA, p<0.05). The proximal contacts did not coincide with the quality defined by the device. Conclusion: The system tested was unable to produce implantsupported single-crown ceramic restorations with marginal, internal and proximal fits matching the digital workflow, with the inferior fits requiring adjustment prior to cementation.

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Over Expression of MN1 Confers Resistance to Chemotherapy In Vitro and In Vivo

Blood ◽

10.1182/blood.v116.21.969.969 ◽

2010 ◽

Vol 116 (21) ◽

pp. 969-969

Author(s):

Timothy Pardee ◽

Teresa Mascenik ◽

Britt H. Bolemon ◽

Guerry J Cook

Keyword(s):

Bone Marrow ◽

The United States ◽

Genetic Alterations ◽

T Test ◽

Over Expression ◽

Student’S T ◽

Worse Prognosis ◽

Student’S T Test

Abstract Abstract 969 Acute myeloid leukemia (AML) is an accumulation of immature myeloid precursors that leads to progressive marrow failure and death. This disease affects approximately 12,000 people per year in the United States, causing 9,000 deaths. Despite decades of active research the overall 5 year survival remains a dismal 30–40%. The backbone of initial therapy for the last 30 years is combination chemotherapy containing cytarabine (Ara-C) and an anthracycline. Resistance to these therapies is a major problem and most patients diagnosed with AML will ultimately die from resistant disease. AML is characterized by heterogeneous genetic alterations that can be used to delineate prognosis. Using standard karyotyping techniques patients can be divided into good, intermediate and poor prognostic categories. There is a clear link between these chromosomal aberrations and response to chemotherapy as complete remission rates are significantly different between groups. Patients with no detectable cytogenetic abnormality fall into an intermediate prognostic group with a very heterogeneous outcome. Recent work has begun to uncover submicroscopic genetic alterations that effect prognosis for these patients. These alterations can be mutations, over or under expression of a particular gene. The MN1 gene encodes a transcription co-factor first identified by its involvement in a balanced translocation in a patient with a meningioma. Since its initial description it has been found over-expressed in multiple AML patient samples. There are several reports that over-expression of MN1 confers a worse prognosis in AML. High MN1 expressers were less likely to achieve a remission and had a lower 3 year survival rate. Additionally, over expression of MN1 in murine bone marrow leads to AML in transplanted recipients and predicts for resistance to ATRA in elderly AML patients. However, the effect of MN1 over expression on response to standard chemotherapy is currently unknown. To answer this question we used a murine model of AML driven by MLL-ENL. AML blasts were infected with retroviral vectors that contained MN1 and a GFP reporter. Partially infected blast populations were then exposed to various concentrations of either Ara-C or doxorubicin and the ratio of GFP positive and negative cells was compared to untreated controls. When blasts were exposed to 150 nM Ara-C the GFP+ percentage went from 21.10 (+/− 0.5302) in the control samples to 35.68 (+/−1.230) in the treated samples. This result was even more profound when cells were treated with 15 ng/ml doxorubicin where the percentage went from 21.10 (+/− 0.5302) to 80.27 (+/−1.615). Both results were highly statistically significant by two tailed student's t test with p values of 0.004 and <0.0001 respectively. Consistent results were obtained in multiple different infections and with separately derived MLL-ENL lines. These data demonstrate that blasts expressing MN1 had an advantage when exposed to either Ara-C or doxorubicin although the effect was far more pronounced with doxorubicin exposure. MN1 expressing blasts were also resistant to the combination of Ara-C and doxorubicin. In order to determine if MN1 conferred resistance to Ara-C and doxorubicin in vivo we injected sublethally irradiated, Ly5.1+ C57Bl6 recipients with a partially infected population of blasts. Ly5.1+ animals do not express the Ly5.2 allele; thus, staining cells for Ly5.2 allows differentiation of leukemic cells from endogenous marrow. Eight days after injection of blasts animals were treated with 100 mg/kg Ara-C plus 3 mg/kg doxorubicin daily for 5 days or observed. On day 6 animals were sacrificed and bone marrow from bilateral femurs was harvested, stained for Ly5.2 and analyzed by flow cytometery. Animals treated with Ara-C plus doxorubicin had 90.58% (+/−0.6638) Ly5.2+, GFP+ blasts compared to 55.38% (+/−5.245) in control animals. This result was highly statistically significant with a p value of <0.0001 by two tailed student's t test. This observation was reproducible in a separately derived MLL-ENL driven cell line. These data suggest that over expression of MN1 in this murine AML model confers resistance to both Ara-C and doxorubicin in vitro and in vivo and provides a biological explanation for the clinical observation that it confers a worse prognosis. The mechanisms involved in this resistance are currently under study. Disclosures: No relevant conflicts of interest to declare.

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Comparing Torque Loss in Standard Implants and Short Implants with Increased Vertical Cantilever Abutments: an In Vitro Study

Brazilian Dental Science ◽

10.14295/bds.2021.v24i1.1985 ◽

2020 ◽

Vol 24 (1) ◽

Author(s):

Ezzatollah Jalalian ◽

Zahra Yousofi

Keyword(s):

In Vitro Study ◽

Longitudinal Axis ◽

Screw Loosening ◽

Reverse Torque ◽

Short Implants ◽

Significant Difference ◽

Torque Loss ◽

Student’S T ◽

Abutment Screw

Objectives: With regard to the prevalence of abutment screw loosening (SL) and bone height reduction, particularly in the posterior regions of the jaws, as well as the contradictory issue of applying short implants instead of surgeries, along with all preparations associated with longer implants, the present study aimed to compare the amount of torque loss in short implants with increased vertical cantilever abutments and standard ones. Material and Methods: In this experimental study, a total number of 20 implants (MegaGen Implant Co., Ltd, South Korea) with 4.5 mm diameter including 10 short implants (7 mm) and 10 standard ones (10 mm) were utilized. Using a surveyor, fixtures were perpendicularly mounted in 13×34 mm resin for short implants and 19×34 mm resin for standard ones. The abutments of the same height but different cuff heights (2.5 mm for the standard implants and 5.5 mm for the short ones) were then tightened with 30 N.cm, via a digital torque meter. To compensate the settling effect, the abutment screw was re-tightened with 30 N.cm after 10 min. Upon applying 500,000 cycles at 75 N.cm and 1 Hz along the longitudinal axis on each sample, blind reverse torque value (RTV) was measured with a digital torque meter. The data were finally analyzed using Student’s t-test. Results: Both groups experienced torque loss, but there was no statistically significant difference between the case and control groups in terms of abutment SL (p = 0451). Conclusion: Short implants seem to be a good mechanical alternative in emergencies with respect to torque loss and abutment SL. KEYWORDS Reverse torque value; Cyclic loading, Short implant; Screw loosening; Crown-implant ratio; Torque loss.

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RESPONSE OF TURMERIC EXPLANT ON CYTOKININ AND AUXIN IN MURASHIGE AND SKOOG

Jurnal Penelitian Saintek ◽

10.21831/jps.v24i1.19784 ◽

2019 ◽

Vol 24 (1) ◽

pp. 1-12

Author(s):

Mita Indriani ◽

Erni Suminar ◽

Noladhi Wicaksana ◽

Denny Sobardini ◽

Sulistyaningsih Sulistyaningsih ◽

...

Keyword(s):

Tissue Culture ◽

T Test ◽

Test Method ◽

Seed Technology ◽

Planting Material ◽

Randomized Design ◽

Student’S T ◽

And Control ◽

Student’S T Test

This study was aimed at determining the concentration of several types of cytokinins and auxin for the induction of turmeric shoots in vitro. The research was conducted at the Tissue Culture Seed Technology Laboratory, Faculty of Agriculture, Padjadjaran University, Jatinangor. The study was conducted from October 2017 to February 2018. The source of planting material is in the form of shoots from the turmeric rhizome. The source of explants or planting material came from the field collected at the Tissue Culture Seed Technology Laboratory, Faculty of Agriculture, Padjadjaran University. Explants were taken from rhizome buds with a size of 0.6-2.0 cm. The experiment used a Completely Randomized Design which was analyzed using the Student’s T-test method. The number of experimental and control groups in this study were seven groups. Variation in treatment with different BAP, thidiazuron, zeatin, and NAA concentrations in each group. The results show that Thidiazuron 1 mgL-1 + NAA 1 mgL-1 gives better results on the percentage of live explants and number of shoots on turmeric plants (Curcuma domestica Val.) Clones 41 at the age of 14 weeks after planting.RESPONS EKSPLAN KUNYIT PADA SITOKININ DAN AUKSIN DALAM MEDIA MURASHIGE DAN SKOOGPenelitian ini bertujuan untuk mendapatkan salah satu konsentrasi dari beberapa jenis sitokinin dan auksin untuk induksi tunas kunyit secara in vitro. Penelitian dilakukan di Laboratorium Kultur Jaringan Teknologi Benih, Fakultas Pertanian, Universitas Padjadjaran, Jatinangor. Waktu pelaksanaan penelitian ini dimulai pada awal bulan Oktober 2017 sampai bulan Februari 2018. Sumber bahan tanam berupa tunas dari rimpang tanaman kunyit. Sumber eksplan atau bahan tanam berasal dari lapangan yang dikoleksi di Laboratorium Kultur Jaringan Teknologi Benih, Fakultas Pertanian, Universitas Padjadjaran. Eksplan diambil dari mata tunas rimpang dengan ukuran 0,6-2,0 cm. Percobaan menggunakan Rancangan Acak Lengkap yang dianalisis menggunakan metode Student’s T-test. Jumlah kelompok eksperimen dan kontrol dalam penelitian ini adalah tujuh kelompok. Variasi perlakuan dengan penambahan konsentrasi BAP, thidiazuron, zeatin, dan NAA yang berbeda pada setiap kelompok. Hasil penelitian ini menunjukkan bahwa Thidiazuron 1 mgL-1 + NAA 1 mgL-1 memberikan hasil yang lebih baik pada persentase eksplan hidup dan jumlah tunas pada tanaman kunyit (Curcuma domestica Val.) klon 41 pada umur 14 MST (Minggu Setelah Tanam).

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158 RELATIONSHIP BETWEEN FOURTH CELL CYCLE DURATION AND POST-TRANSFER VIABILITY IN IN VITRO-FERTILIZED BOVINE EMBRYOS

Reproduction Fertility and Development ◽

10.1071/rdv24n1ab158 ◽

2012 ◽

Vol 24 (1) ◽

pp. 191

Author(s):

S. Sugimura ◽

Y. Hashiyada ◽

Y. Aikawa ◽

M. Ohtake ◽

H. Matsuda ◽

...

Keyword(s):

Cell Cycle ◽

Embryo Transfer ◽

T Test ◽

Cycle Duration ◽

Bovine Embryos ◽

Cell Cycles ◽

Cell Cycle Duration ◽

Student’S T ◽

Student’S T Test

In cattle, the prediction of embryonic viability after embryo transfer is an important research target. A previous study has indicated that the duration of the fourth cell cycle at the time of maternal-zygotic transition, which is involved in in vitro embryonic development, may be an indicator of blastocyst formation; this study showed that embryos with a short fourth cell cycle have a better potential of developing into blastocysts than those with a long fourth cell cycle (Lequarre et al. 2003 Biol. Reprod. 69, 1707–1713). However, the relationship between the fourth cell cycle duration and post-transfer viability of embryos is unclear. The aim of the present study was to examine the effect of the fourth cell cycle duration on embryo development after embryo transfer. Twenty-five IVF bovine embryos were cultured in well-of-the-well culture dishes contained 125 μ of CR1aa supplemented with 5% calf serum at 38.5°C in 5% O2 and 5% CO2 for 168 h after insemination. In vitro development of the embryos was monitored using time-lapse cinematography (Sugimura et al. 2010 Biol. Reprod. 83, 970–978). We found that 61% of the blastocysts had a long fourth cell cycle (41.5 ± 5.9 h), which is commonly referred to as the lag phase, whereas the remaining embryos had a short fourth cell cycle (7.4 ± 4.5 h). All the embryos with a short fourth cell cycle exhibited a lag phase in the next cell cycle (32.9 ± 6.6 h). Moreover, embryos with a short fourth cell cycle were found to have a higher blastocyst rate (75.8%) than those with a long fourth cell cycle (48.1%; Student's t-test, P < 0.01). However, embryonic cell number, apoptosis incidence, chromosomal abnormality and O2 consumption were found to be identical between the 2 groups (Student's t-test, P > 0.05). Real-time reverse-transcription PCR results of the individual blastocysts showed that the relative expression of 5 genes related to pregnancy reorganization, placentation and fetal growth—namely, CDX2, IFN-τ, PLAC8, AKR1B1 and IGF2R—did not differ between the 2 groups (Student's t-test, P > 0.05). Furthermore, blastocysts derived from embryos with long (n = 30) and short (n = 19) fourth cell cycles were transferred into 49 recipient cows; we did not observe any difference between the long and short fourth cell cycles on the rates of pregnancy (long vs short fourth cell cycle, 30.0 vs 52.6%) and delivery (long vs short fourth cell cycle, 30.0 vs 47.4%; Yates' corrected chi-square test, P > 0.10). These results show that blastocysts derived from embryos with either long or short fourth cell cycles have identical developmental competence after embryo transfer. Therefore, the fourth cell cycle duration during maternal-zygotic transition appears to be unavailable as the indicator of post-transfer viability of IVF bovine embryos. This work was supported by the Research and Developmental Program for New Bio-Industry Initiatives.

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Removal torque of zirconia abutment screws under dry and wet conditions

Brazilian Dental Journal ◽

10.1590/s0103-64402010000300009 ◽

2010 ◽

Vol 21 (3) ◽

pp. 225-228 ◽

Cited By ~ 15

Author(s):

Frederico Nigro ◽

Claudio L. Sendyk ◽

Carlos Eduardo Francischone Jr. ◽

Carlos Eduardo Francischone

Keyword(s):

Artificial Saliva ◽

T Test ◽

Removal Torque ◽

Wet Condition ◽

The Mean ◽

Dry And Wet Conditions ◽

Student’S T ◽

Torque Values ◽

Abutment Screw ◽

Student’S T Test

The aim of this study was to verify whether screw abutment lubrication can generate higher preload values compared to non-lubricated screws, a titanium abutment was screwed onto an implant analog and scanned with the Procera System to generate 20 zirconia abutments. MKIII Brånemark implants were clamped to a precision torque device, and the abutments were distributed in dry and wet groups with 10 specimens each. In the wet groups, the inner threads of the implants were filled with artificial saliva. All abutments were fastened with a Torqtite screw under 32 Ncm. Ten detorque measurements were performed per group pushing the reverse button of the Torque controller soon after screw tightening with values registered. The mean detorque values were calculated and compared by a Student's t test (?=0.05). The wet condition presented significantly higher mean detorque than the dry condition (31.5 ± 1.2 versus 27.5 ± 1.5 Ncm, respectively; p=0.0000024). In conclusion, there was always a loss in the initial torque values when the removal torque was measured under both conditions. The wet condition presented higher mean torque than the dry condition. Better preload values were established in the wet group, suggesting that the abutment screw must be lubricated in saliva to avoid further loosening.

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