Journal articles: 'L 14'

1

Krenitsky, Paul J., and Dale L. Boger. "Preparation of the 14-membered l,l-cycloisodityrosine subunit of RP 66453." Tetrahedron Letters 43, no. 3 (January 2002): 407–10. http://dx.doi.org/10.1016/s0040-4039(01)02194-3.

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2

Werner-Zwanziger, Ulrike, Marcia Ziegeweid, Bruce Black, and Alexander Pines. "Nitrogen-14 SQUID NQR of L-Ala-L-His and of Serine." Zeitschrift für Naturforschung A 49, no. 12 (December 1, 1994): 1188–92. http://dx.doi.org/10.1515/zna-1994-1213.

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Abstract14N nuclear quadrupole resonance spectroscopy, detected with a Superconducting Quantum Interference Device, makes possible the study of nitrogen environments in amino acids and small peptides. The present experiments characterize: 1) the effects of intermolecular interactions upon the amino nitrogen of serine upon cocrystallization of the stereoisomers in a range of concentrations; 2) the changes of the amino and imidazole nitrogen environments brought about by combining L-Alanine and L-Histidine into the dipeptide L-Ala-L-His.

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3

Khawaja, H. I. T., and J. R. Ellis. "Colchicine-induced desynaptic mutations in Lathyrus odoratus L. and L. pratensis L." Genome 29, no. 6 (December 1, 1987): 859–66. http://dx.doi.org/10.1139/g87-147.

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Partially desynaptic mutant plants were observed in colchicine-treated, undoubled Lathyrus odoratus (2n = 14) and L. pratensis (2n = 14) and also in a L. odoratus (C1) seedling with 2n = 27 and in a triploid (C0) L. pratensis (2n = 21). The affected plants showed varying numbers of univalents at metaphase I and reduced fertility. A total of seven independent cases of desynapsis were observed. In diploid L. odoratus the cytology of one of the mutants was recorded for three consecutive generations and all the plants showed partial desynapsis. This suggested that the mutant plants were true breeding and the cytological abnormality was an inherited trait. Inheritance studies in partially and totally desynaptic mutant lines of diploid L. odoratus indicated that the two mutations were monogenic recessive, nonallelic, and not linked. Key words: Lathyrus, desynaptic mutation.

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4

Matloubi, Hojatollah, Abbas Shafiee, Nader Saemian, Gholamhossein Shirvani, and Fariba Johari Daha. "Synthesis of carbon-14 labelled l,5 diaryl-[5-14C]-l,2,3-triazolines." Journal of Labelled Compounds and Radiopharmaceuticals 47, no. 1 (January 2004): 31–36. http://dx.doi.org/10.1002/jlcr.794.

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5

Tanveer, A., M. Ayub, and R. Ahmad. "Competition Effect of Chenopodium album L. for Potassium and Grain Yield in Wheat (Triticum aestivum L.)." Journal of Agricultural and Marine Sciences [JAMS] 6 (January 1, 2001): 11. http://dx.doi.org/10.24200/jams.vol6iss0pp11-14.

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A field experiment was conducted to estimate potassium (K) and yield losses by Chenopodium album in wheat under different competition periods. The study consisted of zero competition, competition for 3,4,5,6,7,8 weeks after emergence (WAE), and for full season. Potassium concentration in C. album was maximum (4.91 %) when it was allowed to compete with wheat for 6 WAE. Full season competition resulted in a maximum K uptake (8.22 kg ha-1) by C. album. Maximum K concentration (4.39 %) in wheat was recorded in 4 WAE competition period whereas maximum K uptake (98.40 kg ha-1) by wheat was in full season competition period. There was a linear increase in dry wheat of C. album with increase in competition period. Grain yield decreased significantly beyond 3-4 WAE competition periods and maximum decrease (25.59 %) in grain yield was observed in full season competition.

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6

Hu, Sheng-Cao, Jin Yang, Chao Chen, Jun-Rong Song, and Wei-Dong Pan. "Design, Synthesis of Novel Tetrandrine-14-l-Amino Acid and Tetrandrine-14-l-Amino Acid-Urea Derivatives as Potential Anti-Cancer Agents." Molecules 25, no. 7 (April 9, 2020): 1738. http://dx.doi.org/10.3390/molecules25071738.

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Tetrandrine, a dibenzyltetrahydroisoquinoline alkaloid isolated from the root of the traditional Chinese medicinal plant Stephania tetrandra S. Moore, a member of the Menispermaceae, showed anti-cancer activity by inhibiting cell proliferation, preventing cell cycle progress and induction of cell death and autophagy. In this study, twelve tetrandrine-l-amino acid derivatives and twelve tetrandrine-14-l-amino acid-urea derivatives were designed and synthesized, using C14-aminotetrandrine as raw material. Then the preliminary in vitro anti-cancer activities of these derivatives against human breast cancer cell line MDA-MB-231, human leukemia cell lines HEL and K562 were evaluated. The in vitro cytotoxicity results showed that these derivatives exhibited potent inhibitory effects on cancer cell growth, and the primary structure-activity relationships were evaluated. Notably, compound 3f exhibited satisfactory anticancer activity against all three cancer cell lines, especially the HEL cell line, with the IC50 value of 0.23 µM. Further research showed that 3f could induce G1/S cycle arrest and apoptosis in a dose- and time- dependent manner on the leukemia cell line HEL. The results suggested that 3f may be used as a potential anti-cancer agent for human leukemia.

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7

Krenitsky, Paul J., and Dale L. Boger. "ChemInform Abstract: Preparation of the 14-Membered L,L-Cycloisodityrosine Subunit of RP 66453." ChemInform 33, no. 16 (May 22, 2010): no. http://dx.doi.org/10.1002/chin.200216213.

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8

Maligranda, Lech, and Natalia Sabourova. "Real and complex operator norms between quasi-Banach L^p-L^q spaces." Mathematical Inequalities & Applications, no. 2 (2011): 247–70. http://dx.doi.org/10.7153/mia-14-21.

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9

Santanen, Ajra, and Liisa Kaarina Simola. "Metabolism of l [U-14 C]-arginine and l [U-14 C]-ornithine in maturing and vernalised embryos and megagametophytes of Picea abies." Physiologia Plantarum 107, no. 4 (December 1999): 433–40. http://dx.doi.org/10.1034/j.1399-3054.1999.100409.x.

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10

Ueda, Shuhei, Ryohei Nomoto, Ken-ichi Yoshida, and Ro Osawa. "Comparison of three tannases cloned from closely related lactobacillus species: L. Plantarum, L. Paraplantarum, and L. Pentosus." BMC Microbiology 14, no. 1 (2014): 87. http://dx.doi.org/10.1186/1471-2180-14-87.

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11

Tavallaei, Narguess, Mohammad Ramezanpour, and Behrooz Olfatian Gillan. "Structural transition between $L^{p}(G)$ and $L^{p}(G/H)$." Banach Journal of Mathematical Analysis 9, no. 3 (2015): 194–205. http://dx.doi.org/10.15352/bjma/09-3-14.

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12

Prasad, K. C. "L-14 Supra-omohyoid neck dissection in oral cavity malignancies." Oral Oncology Supplement 1, no. 1 (January 2005): 36–37. http://dx.doi.org/10.1016/s1744-7895(05)80031-8.

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13

Cirillo, Vincent J., and Karen Reeds. "Eloge: David L. Cowen, 1 September 1909–14 April 2006." Isis 98, no. 2 (June 2007): 351–53. http://dx.doi.org/10.1086/518195.

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14

Pintz, János. "Some new density theorems for Dirichlet $L$-functions." Banach Center Publications 118 (2019): 231–44. http://dx.doi.org/10.4064/bc118-14.

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15

Hassanain, A. A. "Drying sage (Salvia officinalis L.) in passive solar dryers." Research in Agricultural Engineering 57, No. 1 (March 21, 2011): 19–29. http://dx.doi.org/10.17221/14/2010-rae.

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Sage plants (Salvia officinalis L.) were dried in the passive dryers in different times of the year. Different passive solar dryers were used to achieve the socio-economical benefits from drying the medicinal plants growing in Sinai area. Drying sage plants might be a source to increase the Bedouin income instead of cannabis or marijuana, especially if it is exported abroad. Four drying methods were used in this investigation to dry sage in two seasons, namely August 2009 and March 2010 before flowering stage. Plants were dried in an Unglazed transpired passive solar dryer with 100% exposure to direct sun-rays, in a greenhouse dryer covered with shading cloth with 50% exposure to direct sun-rays, and with 0% sun-rays while the medicinal plants were protected from sun i.e. in shaded barn. Investigations were carried out under the environmental weather conditions of Ismailia, Egypt. The study revealed that sage can be dried at different times of the year even before the flowering stage of the plants.

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16

Kurniawan, Hendra, Dwisari Dillasamola, and Romian Br Rumapea. "UJI AFRODISIAK DAUN KATUK (Sauropus androgynus (L.) Merr PADA MENCIT (Mus muscullus L) OBESITAS." SCIENTIA : Jurnal Farmasi dan Kesehatan 10, no. 2 (August 18, 2020): 235. http://dx.doi.org/10.36434/scientia.v10i2.343.

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Penelitian ini bertujuan untuk mengetahui pengaruh pemberian seduhan daun katuk (Sauropus androgynus (L.) Merr sebagai afrodisiak. Seduhan daun katuk diberikan secara oral setiap hari selama 14 hari. Parameter uji yang diamati adalah jumlah aktivitas pendekatan (Introduction), menunggang (Climbing), dan kawin (Coitus). Terdapat 4 kelompok perlakuan yaitu kelompok kontrol negatif, kelompok dosis I diberi 100 mg/kg BB, kelompok dosis II diberi 125mg/kg BB dan kelompok dosis III diberi 150 mg/kg BB, masing-masing kelompok terdiri dari 4 ekor mencit. Pengamatan dilakukan selama 14 hari selama 1 jam setelah pemberian seduhan daun katuk (Sauropus androgynus (L.) Merr pada mencit putih jantan obesitas. Hasil penelitian dianalisi menggunakan uji One Way ANOVA untuk mengetahui signifikan antara kelompok uji dengan kelompok kontrol. Dari hasil penelitian terdapat perbedaan bermakna antara kelompok uji dan kelompok kontrol, dimana mencit yang diberi seduhan daun katuk dapat meningkatkan afrodisiak dibandingkan dengan kelompok kontrol. Dapat disimpulkan bahwa pemberian seduhan daun katuk selama 14 hari dapat meningkatkan afrodisiak mencit putih jantan obesitas

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17

Djamgoz, M. B. A. "Neuromethods, volume 14—Neurophysiological techniques. Basic methods and concepts." Neurochemistry International 21, no. 2 (September 1992): 304. http://dx.doi.org/10.1016/0197-0186(92)90163-l.

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18

Espinosa, Rafael Zorzenoni, Flávia Helena De Moura Libório, Luciano Ivano Da Silva, Patricia Da Costa Zonetti, Anny Rosi Mannigel, Daniele Fernanda Felipe, Aline Maria Orbolato Gonçalves-Zuliani, and Graciene De Souza Bido. "ATIVIDADE ALELOPÁTICA DE EXTRATO AQUOSO DE Eucalyptus grandis Hill ex Maiden SOBRE ALFACE (Lactuca sativa L.) e PICAO-PRETO (Bidens pilosa L.)." Revista Valore 4 (November 30, 2019): 1–14. http://dx.doi.org/10.22408/reva4020193111-14.

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Planta invasora de difícil controle, o picão-preto (Bidens pilosa L.) pode ser encontrado em quase todo o Brasil, inclusive nas áreas agrícolas ocupadas com espécies olerícolas, como a alface (Lactuca sativa L.). O controle das plantas invasoras tem sido realizado principalmente pelo uso de herbicidas, promovendo impacto ambiental e risco a saúde humana e animal. Assim, o objetivo deste trabalho foi avaliar o potencial alelopático do extrato aquoso de folhas secas de Eucalyptus grandis Hill ex Maiden sobre a germinação e o crescimento inicial de alface e picão-preto. Foram analisadas quatro concentrações do extrato aquoso (25, 50, 75 e 100%), além da testemunha (0%). O delineamento experimental foi inteiramente casualizado, com três repetições de cada tratamento, constituídas por 50 sementes de alface ou picão-preto distribuídas em gerbox e mantidas em câmara tipo B.O.D com fotoperíodo de 12h a 25ºC por 7 dias. Os resultados obtidos indicaram que Eucalyptus grandis Hill ex Maiden não apresentou potencial alelopático em relação às plântulas de picão-preto e a baixas concentrações pouco influenciou a germinação e o crescimento inicial de plântulas de alface.

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19

Grant, William F. "A chromosome atlas and interspecific – intergenic index for Lotus and Tetragonolobus (Fabaceae)." Canadian Journal of Botany 73, no. 11 (November 1, 1995): 1787–809. http://dx.doi.org/10.1139/b95-191.

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Basic chromosome numbers in Lotus are x = 5, 6, and 7. It is considered that evolution has proceeded in the genus by means of a descending aneuploid series from an eight-chromosomed ancestor. Chromosome numbers for species of Tetragonolobus are based on x = 7. Somatic chromosome numbers are reported for 108 species and 38 varieties. The chromosome numbers for five species (L. hamatus Greene, 2n = 14, L. haydonii (Orcutt) Greene, 2n = 14, L. hintoniorum B.L. Turner, 2n = 14, L. mearnsii Britton, 2n = 14, L. utahensis Ottley, 2n = 14) and seven varieties (L. argophyllus (Gray) Green var. argenteus Dunkle, 2n = 14, L. dendroideus var. traskiae (Eastwood ex Noddin) Isely, 2n = 14, L. heermanii (Durand et Hilgard) Greene var. orbicularis (Gray) Isely, 2n = 14, L. junceus (Benth.) Greene var. biolettii (Greene) Ottley, 2n = 14, L. strigosus var. hirtellus (Greene) Ottley, 2n = 14, L. strigosus var. tomentellus (Greene) Isely, 2n = 14, L. uliginosus ssp. vestitus (Lange) A. Pedersen, 2n = 12) are reported for the first time. Natural diploid, tetraploid, and hexaploid plants are reported for L. alpinus. Several species are reported as possessing B chromosomes. Mixoploidy is reported to occur in three species (L. alpinus, L. glacialis, L. glareosus). In addition, chromosome numbers are given for plants regenerated from calluses grown in tissue culture having both heteroploidy, euploidy, and mixoploidy. Root nodules are reported with tetraploid and octoploid cells in addition to the normal number of chromosomes. Trisomie series have been partially developed in L. tenuis and L. uliginosus. Polytene chromosomes were observed in suspensor cells of three species of Lotus. Feulgen cytophotometric measurements, to determine the DNA nuclear content, were made for 16 species of Lotus and one species of Tetragonolobus. The majority of the studies in Lotus concern the economic species L. corniculatus, L. tenuis, and L. uliginosus. Interspecific hybridization was carried out in different combinations between diploids, autoploids, and amphidiploids. Intergeneric hybrids were attempted by somatic hybridization, protoplast fusion, and asymmetric hybridization between Lotus and other species (Glycine max, Medicago sativa, Oryza sativa). Key words: chromosome numbers, DNA values, Fabaceae, Lotus species, interspecific hybrids, intergeneric hybrids, Tetragonolobus.

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20

Castronovo, Vincent, Frank Luyten, Frederic van den Brûle, and Mark E. Sobel. "Identification of a 14-kDa laminin binding protein (HLBP14) in human melanoma cells that is identical to the 14-kDa galactoside binding lectin." Archives of Biochemistry and Biophysics 297, no. 1 (August 1992): 132–38. http://dx.doi.org/10.1016/0003-9861(92)90650-l.

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21

Schumann, H., B. Neumann, and H. G. Stammler. "Spektroskopische und strukturelle Aspekte der Protonierung von Tetraaza[14]annulen-Dianionen / Spectroscopic and Structural Aspects of the Protonation of Tetraaza[14]annulene Dianions." Zeitschrift für Naturforschung B 51, no. 9 (September 1, 1996): 1255–66. http://dx.doi.org/10.1515/znb-1996-0908.

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The effects of increasing protonation upon two [ 14]annulene dianions prepared by reaction of LiCH3 with 5,14-dihydro-6,8,15,17-tetramethyldibenzo[b,i][l,4,8,l l]tetraazacyclotetradecine (IIIb) and 5,14-dihydro-6,17-dimethyl-8,15-diphenyldibenzo[b,i][l,4,8,l 1 ]tetraazacyclotetradecine (IIIc) have been studied by 1H, 13C NMR and UV-VIS spectroscopy in solution. The crystal structures of the diprotonated macrocycle IIIb x 2 HPF6 (lIb) and of the neutral macrocycle IIIc have been determined by X-ray diffraction. For lIb, the crystal system is monoclinic with a space group of P21/n: a = 12.019(3), b = 13.864(6), c = 33.547(9) Å, β = 99.82(2)°, Z = 8 . The final R factor is 0.083 for 5520 observed reflections (745 variables). For IIIc, the crystal system is triclinic with a space group of P1̄: a = 9.923(8), b = 11.633(9), c = 14.318(12) Å, ct = 110.50(6)°, β = 98.86(7)°, 7 = 103.12(6)°, Z = 2. The final R factor is 0.081 for 2174 observed reflections and 191 variables. Comparison of these structural data together with those obtained from the literature for the deprotonated macrocycle IVb and a wide variety of substituted [ 14]annule derivatives allows for the first time a discussion of protonation effects upon the highly π-conjugated pentadiimidato moiety. Additional information is derived from NMR and UV-VIS data.

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22

Conte, D., C. Mandelli, M. Cesana, R. Ferrini, M. Marconi, and A. Bianchi. "Effectiveness of Erythrocytapheresis in Idiopathic Hemochromatosis. Report of 14 Cases." International Journal of Artificial Organs 12, no. 1 (January 1989): 59–62. http://dx.doi.org/10.1177/039139888901200110.

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Thirteen men and one woman (mean age 48.8 yr ± 6.9, range 36–63) with idiopathic hemochromatosis were treated by erythrocytapheresis. Iron depletion followed 9–60 months treatment (median 24), with 21–203 erythrocytaphereses (mean 93 ± 61) and total iron removal of 4.2–40. 6 g (mean 19 ± 11.9). Trasferrin saturation decreased from 90 ± 8.7% to 17 ± 10.6% and serum ferritin from 3164 μg/L ± 1488 to 60.5 μg/L ± 77.5, and liver iron content normalized in all cases. Initial serum ferritin in the patients who were iron-depleted at 18 months (50%, cumulative percentage) was significantly lower than in those still iron loaded at that time (2280 μg/L ± 940 vs 4049 μg/L ± 1444, p<0.02). Clinical improvement was noted in all cases with about a 30% decrease in insulin requirement in most diabetics. Thus erythrocytapheresis appears to be effettive and safe in obtaining iron depletion in idiopathic hemochromatosis.

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23

Gorochov, A. V. "Taxonomy of the katydids (Orthoptera: Tettigoniidae) from East Asia and adjacent islands. Communication 14." Far Eastern entomologist 434 (July 2, 2021): 1–25. http://dx.doi.org/10.25221/fee.434.1.

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The Indo-Malayan genus Lipotactes Br.-W. is subdivided into nine subgenera: Lipotactes s. str.; Mortoniellus Griff., stat. n.; Prolipotactes subgen. n.; Dialipotactes subgen. n.; Neolipotactes subgen. n.; Miolipotactes subgen. n.; Sublipotactes subgen. n.; Analipotactes subgen. n.; Eulipotactes subgen. n. The following new species and subspecies of this genus are described from Borneo, Sumatra and Sulawesi: L. (L.) alienus lambir subsp. n.; L. (L.) a. similajau subsp. n.; L. (L.) a. kubah subsp. n.; L. (L.) sumatranus sp. n.; L. (P.) hamatus wartabone subsp. n.; L. (P.) h. lorelindu subsp. n.; L. (P.) h. irisovi subsp. n. Some former species taxa are reduced to subspecies ones: L. (S.) khmericus samkos Ingr., stat. n.; L. (S.) kh. saengeri Ingr., stat. n.; L. (S.) discus productus Ingr., stat. n. For several other taxa of this genus, new localities and some other data are given.

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Loría-Quirós, Carlos Luis, and Franklin Herrera Murillo. "Respuesta de 14 cultivares de melón (Cucumis melo L.) al cletodim." Agronomía Mesoamericana 20, no. 2 (February 20, 2008): 327. http://dx.doi.org/10.15517/am.v20i2.4949.

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25

Serra, Francisca, Andreu Palou, and Antoni Pons. "Enzymic determination of carbon-14-labeled L-alanine in biological samples." Analytical Chemistry 59, no. 14 (July 15, 1987): 1841–43. http://dx.doi.org/10.1021/ac00141a022.

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26

Ottenkamp, Jaap, and John Rohmer. "Caroline L. D. C. Bruins (March 14, 1914–June 17, 2005)." Cardiology in the Young 15, no. 06 (November 18, 2005): 669. http://dx.doi.org/10.1017/s1047951105001927.

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Reid, I. Neill, E. Lewitus, Adam J. Burgasser, and K. L. Cruz. "2MASS J22521073−1730134: A Resolved L/T Binary at 14 Parsecs." Astrophysical Journal 639, no. 2 (March 10, 2006): 1114–19. http://dx.doi.org/10.1086/499484.

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28

Wani, Minal, Snehal Pande, and Nitin More. "Callus induction studies in Tridax procumbens L." International Journal of Biotechnology Applications 2, no. 1 (June 30, 2010): 11–14. http://dx.doi.org/10.9735/0975-2943.2.1.11-14.

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29

Shulman, Stanford T. "A Conversation with Sheldon L. Kaplan, MD." Pediatric Annals 42, no. 5 (May 1, 2013): 216. http://dx.doi.org/10.3928/00904481-20130426-14.

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Verdon, Noémi, and Michio Yano. "Al-Bīrūnī’s India, Chapter 14." History of Science in South Asia 8 (May 14, 2020): 57–76. http://dx.doi.org/10.18732/hssa.v8i.54.

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This article provides an English translation of Chapter 14 of al-Bīrūnī's Kitāb taḥqīq mā li-l-Hind. The whole book was translated by E. Sachau (as Alberuni's India) more tha 100 years ago. Thanks to the recent works by David Pingree, especially the Census of the Exact Sciences in Sanskrit, we can offer many improvements and additions to Sachau's translation. We focused our attention to Chapter 14 of the same book where we find much interesting information about the history of Indian astronomy and mathematics. In the Appendix we have compared the table of contents of the Brāhmasphutasiddhānta as reported by al-Bīrūnī (in Arabic) and those given in Dvivedin's Sanskrit text.

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Belov, A. P. "35 P 14 How to measure the contamination of aerosols." Journal of Aerosol Science 24 (January 1993): S407—S408. http://dx.doi.org/10.1016/0021-8502(93)90296-l.

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Rengo, C., C. Goracci, G. Ametrano, N. Chieffi, G. Spagnuolo, S. Rengo, and M. Ferrari. "Marginal Leakage of Class V Composite Restorations Assessed Using Microcomputed Tomography and Scanning Electron Microscope." Operative Dentistry 40, no. 4 (June 1, 2015): 440–48. http://dx.doi.org/10.2341/14-022-l.

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SUMMARY Objective The aim of the study was to compare in Class V composite restorations marginal leakage measurements obtained with microcomputed tomography (micro-CT) and scanning electron microscopy (SEM) observations. Methods Class V cavities were prepared on 10 human molars and restored using Optibond FL (Kerr, Orange, CA, USA) and Premise Flowable (Kerr). Sealing ability was evaluated by assessing silver-nitrate penetration depth along enamel and dentin margins. Leakage was quantified using a scoring system. Micro-CT analysis provided 502 cross-sectional images for each tooth. Microleakage evaluation was performed first on three cross-sections corresponding to the sections examined by SEM, then on all 502 of the obtained micro-CT images. SEM observations were performed first at 20× magnification, then, if showing a zero score, at 80× magnification. Enamel and dentin microleakage scores assigned to corresponding sections through micro-CT and SEM (20×) were compared (Wilcoxon signed-rank test, α=0.05). Results No statistically significant difference in leakage scores emerged between micro-CT and 20×-magnification SEM. Eight tooth sections that were given a zero score under SEM at 20× magnification showed to be infiltrated at the higher magnification (80×). For five teeth a higher score was assigned following scanning of 502 cross-sections than based on the observation of three sections. Conclusions Micro-CT presents as a valid, nondestructive in vitro method to quantitatively evaluate marginal leakage of adhesive restorations.

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Cook, NB, SA Feitosa, A. Patel, Y. Alfawaz, GJ Eckert, and MC Bottino. "Bonding Ability of Paste-Paste Glass Ionomer Systems to Tooth Structure: In Vitro Studies." Operative Dentistry 40, no. 3 (May 1, 2015): 304–12. http://dx.doi.org/10.2341/14-030-l.

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SUMMARY This study investigated the effect of nonrinse conditioners (ie, Ketac Nano Primer [KNP] and GC Self Conditioner [SC]) used as substrate pretreatment and their respective paste-paste resin-modified glass-ionomer cement (RMGIC) (ie, Ketac Nano [KN] and Fuji Filling LC [FF]) on microtensile bond strength to dentin and marginal sealing when compared with traditional RMGIC (ie, Photac Fil [PF] and Fuji II LC [FII]) used in association with polyacrylic acid (ie, Ketac Cavity Conditioner [KC] and GC Cavity Conditioner [CC]). A total of 192 extracted human molars were allocated into eight groups: KNP-KN, KC-KN, KNP-PF, KC-PF, SC-FF, CC-FF, SC-FII, and CC-FII. For microtensile bond strength, the teeth were sectioned to expose occlusal dentin and restored according to the group. After 24 hours the teeth were cut to yield nine beams per tooth (±0.8 mm2). Testing was done using a universal testing machine followed by failure mode classification. For microleakage testing, standardized cavity preparations were made on the buccal cementoenamel junction and restored according to the group. The teeth were thermocycled (500 cycles, 8°C to 48°C), sealed, immersed in methylene blue for 24 hours, and then assessed for microleakage using a stereomicroscope. Microtensile bond strengths in megapascals (mean±SE) were KNP-KN: 14.9 ± 1.6, KC-KN: 17.2 ± 1.5, KNP-PF: 31.2 ± 1.6, KC-PF: 26.2 ± 1.2, SC-FF: 23.6 ± 1.5, SC-FII: 31.2 ± 1.5, and CC-FII: 21.9 ± 1.5. Cervical margins showed more microleakage compared with occlusal margins. Overall, the use of nonrinse conditioners in association with traditional RMGICs demonstrated superior microtensile bond strengths to dentin when compared with the paste-paste RMGICs. Meanwhile, the association between polyacrylic acid (CC) and a traditional RMGIC (FII) led to the least microleakage for cervical locations when compared with all other groups.

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Mohamed, MF, HA El Deeb, IE Gomaa, and EH Mobarak. "Bond Durability of Different Resin Cements to Caries-Affected Dentin Under Simulated Intrapulpal Pressure." Operative Dentistry 40, no. 3 (May 1, 2015): 293–303. http://dx.doi.org/10.2341/14-035-l.

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SUMMARY Objective: To evaluate the durability of the bond of different resin cement systems to normal dentin (ND) and caries-affected dentin (CAD) with and without simulated intrapulpal pressure (IPP). Methods and Materials Molars with midcoronal caries were used. Occlusal enamel was cut to expose both dentin substrates (ND and CAD). Dentin substrates were differentiated using visual, tactile, caries-detecting dye, and dye-permeability methods. Prepared crown segments were equally divided according to the tested resin cement systems: etch-and-rinse resin cement, self-etch resin cement containing methacryloyloxydecyl dihydrogen phosphate (MDP), and self-adhesive resin cement. In addition to the dentin substrates and the resin cement types, the effect of application/storage conditions (with or without simulated IPP and with or without thermocycling) were tested. A microtensile bond strength test was done using a universal testing machine. Failure modes were determined using a scanning electron microscope. Results Etch-and-rinse resin cement strength values were significantly affected by the difference in the dentin substrates as well as the different application/storage conditions. Self-etch adhesive containing MDP bonded equally to ND and CAD and remained stable under all tested conditions. Self-adhesive resin cement revealed a similar bond to ND and CAD; however, its values were the lowest, especially when IPP and thermocycling were combined. Mixed failure was the predominant failure mode. Conclusions Etch-and-rinse resin cement was sensitive to dentin substrate and application/storage conditions. Resin cement with self-etch adhesive containing MDP revealed more reliable bonding to ND/CAD even when IPP and thermocycling were combined. The bonding of the self-adhesive resin cement could not compete with other resin cements.

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Tantbirojn, D., C. Fernando, and A. Versluis. "Failure Strengths of Composite Additions and Repairs." Operative Dentistry 40, no. 4 (June 1, 2015): 364–71. http://dx.doi.org/10.2341/14-042-l.

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SUMMARY Purpose When adding composite to a cured composite restoration, the intent is to achieve the same failure strength as the original restorative material. This study evaluated the failure strengths of added or repaired composite using various chemical and/or mechanical surface treatments. Methods Failure strengths were determined using a four-point bending test. Beam-shaped specimens were fabricated by adding new composite to cured composite (Filtek Supreme Ultra). The cured composites were either fresh or aged seven days (N=10-14). The composite surfaces were left unground or were ground before treatment with various combinations of roughening, acid etching, silane, and dental adhesives (conventional Adper SingleBond Plus or new multimode Scotchbond Universal) and/or tribochemistry (CoJet system). Monolithic composite specimens were the control. Failure strengths were statistically analyzed using one-way analysis of variance and the Fisher protected least significant difference (α=0.05). Results Failure strengths (mean ± standard deviation) when composite was added to unground freshly cured composites (111±25 MPa) and aged composites using a new multimode adhesive with (102±22 MPa) or without (98±22 MPa) tribochemical treatment were not significantly lower than the monolithic specimens (122±23 MPa). Grinding the surfaces of freshly cured composite significantly reduced failure strength, either with (81±30 MPa) or without (86±31 MPa) use of conventional adhesive. Failure strengths of aged composites were also significantly lower (51±21 MPa with SingleBond Plus), even after tribochemical treatment (71±29 MPa with SingleBond Plus; 73±35 MPa with Silane-Visiobond). Conclusions Using a new multimode adhesive when adding composite to freshly cured or aged composite substrates recovered the failure strength to that of the original monolithic composite.

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Diniz, MB, RCL Cordeiro, and AG Ferreira-Zandona. "Detection of Caries Around Amalgam Restorations on Approximal Surfaces." Operative Dentistry 41, no. 1 (January 1, 2016): 34–43. http://dx.doi.org/10.2341/14-048-l.

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SUMMARYTo evaluate the in vitro performance of the International Caries Detection and Assessment System (ICDAS) visual examination, bitewing radiography (BW), and the DIAGNOdent 2190, a pen-type laser fluorescence device (LFpen), in detecting caries around amalgam restorations on approximal surfaces. Approximal surfaces (N=136) of permanent posterior teeth (N=110) with Class II amalgam restorations were assessed twice by two experienced examiners using ICDAS, BW, and LFpen. The occurrence of proximal overhangs was also evaluated. The teeth were histologically prepared and assessed for caries extension. Different cutoff limits for the LFpen were used. Intraexaminer and interexaminer reproducibility showed moderate to good agreement for all the methods (weighted κ/intraclass correlation coefficient=0.40 to 0.87). The specificities at D1 (all visible lesions affecting enamel) and D3 (lesions extended into dentin) were, respectively, 0.41 and 0.82 for ICDAS, 0.70 and 0.82 for BW, and 0.77-0.89 and 0.88-0.94 for LFpen. The sensitivities were 0.80 and 0.52 for ICDAS, 0.56 and 0.51 for BW, and 0.04-0.23 and 0.01-0.02 for LFpen at D1 and D3, respectively. At the D1/D3 thresholds, the accuracy and the area under the receiver operating characteristic curve (Az) values were similar and statistically higher for ICDAS (0.65/0.68 and 0.633/0.688) and BW (0.64/0.68 and 0.655/0.719), respectively; whereas, LFpen presented lower accuracy (0.37-0.44/0.49-0.52) and Az (0.390-0.454/0.345-0.395) values. The occurrence of overhangs (26.8%) was shown to be irrelevant in determining the presence of secondary caries. The ICDAS and BW methods presented the best performance in detecting caries lesions affecting enamel and dentin on approximal surfaces of amalgam restorations.

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Muñoz, MA, I. Luque-Martinez, P. Malaquias, V. Hass, A. Reis, NH Campanha, and AD Loguercio. "In Vitro Longevity of Bonding Properties of Universal Adhesives to Dentin." Operative Dentistry 40, no. 3 (May 1, 2015): 282–92. http://dx.doi.org/10.2341/14-055-l.

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SUMMARY Purpose To evaluate the immediate and 6-month resin-dentin bond strength (μTBS) and nanoleakage (NL) of universal adhesives that contain or do not contain methacryloyloxydecyl dihydrogen phosphate (MDP) and are used in the etch-and-rinse and self-etch strategies. Methods and Materials Forty caries-free extracted third molars were divided into eight groups for μTBS (n=5). The groups were bonded with the Clearfil SE Bond (CSE) and Adper Single Bond 2 (SB) as controls; Peak Universal, self-etch (PkSe) and etch-and rinse (PkEr); Scotchbond Universal Adhesive, self-etch (ScSe) and etch-and-rinse (ScEr); and All Bond Universal, self-etch (AlSe) and etch-and-rinse (AlEr). After composite restorations, specimens were longitudinally sectioned to obtain resin-dentin bonded sticks (0.8 mm2). The μTBS of the specimens was tested immediately (IM) or after 6 months of water storage (6M) at 0.5 mm/min. Some sticks at each storage period were immersed in silver nitrate and photo developed, and the NL was evaluated with scanning electron microscopy. Data were analyzed with two-way repeated-measures analysis of variance and Tukey test (α=0.05). Results At the IM period, PkSe and PkEr showed μTBS similar to the control adhesives (p>0.05) but increased NL pattern and lower μTBS after 6M (p<0.05). ScSe and ScEr showed intermediary μTBS values at the IM period but remained stable after 6 months (p>0.05). AlSe showed the lowest μTBS (p<0.05), but μTBS and NL remained stable after 6M (p>0.05). AlEr showed higher IM μTBS but showed higher degradation after 6M (p<0.05). Conclusions Universal adhesives that contain MDP showed higher and more stable μTBS with reduced NL at the interfaces after 6 months of water storage.

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Furukawa, M., Jr K-Kaneyama, M. Yamada, A. Senda, A. Manabe, and A. Miyazaki. "Cytotoxic Effects of Hydrogen Peroxide on Human Gingival Fibroblasts In Vitro." Operative Dentistry 40, no. 4 (June 1, 2015): 430–39. http://dx.doi.org/10.2341/14-059-l.

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SUMMARY In-office bleaching is a popular treatment in modern esthetic dentistry. However, bleaching agents sometimes accidentally adhere to the gingiva and peripheral tissues, even when applied by well-trained dentists. This can lead to transient pain and whitish changes in the gingiva. Although these symptoms disappear within several hours, the effects of bleaching agents on gingiva have not been well described in the literature. The present study aimed to elucidate the cytotoxic effects of a bleaching agent on cultured human gingival fibroblasts (HGFs). We performed a comprehensive analysis of the toxic effects of in-office bleaching agents on gingiva using cultured HGFs and DNA microarray. Survival rates of HGFs decreased with increases in the concentration of hydrogen peroxide, which became significant at concentrations of 1.5 × 10−3% or higher at every time point. Concentrations lower than 1.5 × 10−3% did not affect survival rates of HGFs. Cytotoxicity of hydrogen peroxide was significantly weakened by the addition of vitamin E. Stimulation by in-office bleaching agents triggered the proinflammatory cytokine tumor necrosis factor (TNF)–α cascade in gingival fibroblasts. As the TNF-α cascade can be inhibited by vitamin E additives, treatment with vitamin E may protect gingival fibroblasts against the toxic effects of an in-office bleaching agent. The present results suggest that local administration of vitamin E to gingiva before in-office bleaching may be useful for preventing gingival irritation due to accidental adhesion of a bleaching agent.

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Yasa, E., B. Yasa, OS Aglarci, and ET Ertas. "Evaluation of the Radiopacities of Bulk-fill RestorativesUsing Two Digital Radiography Systems." Operative Dentistry 40, no. 5 (September 1, 2015): E197—E205. http://dx.doi.org/10.2341/14-074-l.

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SUMMARY This study investigated the radiopacity values of bulk-fill restoratives by using two digital radiography systems. Nine bulk-fill restoratives and a conventional composite were used in the study. Six disc-shaped specimens were prepared from each of these materials, three each at thicknesses of 1 mm and 2 mm, and tooth slices with these same thicknesses were obtained. As a control, an aluminum step wedge varying in thickness from 0.5 to 10 mm in was used. Three specimens of each of the materials, together with the tooth slice and the aluminum step wedge, were placed over a complementary metal oxide semiconductor (CMOS) sensor and a storage photostimulable phosphor (PPS) plate system and exposed using a dental x-ray unit. The images were analyzed using a software program to measure the mean gray values (MGVs). Five measurements were obtained from each of the restorative materials, the enamel, the dentin, and the stepwedge. The MGVs were converted to the equivalent aluminum thicknesses. Three-way analysis of variance (ANOVA) was used to determine the significance of the differences among the groups. A Tukey test was applied for pairwise comparisons (p<0.05). All composite-based restoratives were found to have greater radiopacities than enamel or dentin. Equia Fil had the lowest radiopacity value. Radiopacity increased as the thicknesses of the restorative material increased. The CMOS system showed significantly higher radiopacity values than the PSP system. In conclusion, all investigated bulk-fill restoratives passed the International Organization for Standardization and American National Standard Institute/American Dental Association requirements for radiopacity values when evaluated with the two digital radiography systems.

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Sgura, R., MC dos Reis, MC Salvadori, AC Hernandes, PF Cesar, and IS Medeiros. "CO2 Laser Glazing Treatment of a Veneering Porcelain: Effects on Porosity, Translucency, and Mechanical Properties." Operative Dentistry 40, no. 3 (May 1, 2015): 247–54. http://dx.doi.org/10.2341/14-079-l.

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SUMMARY This work tested CO2 laser as a glazing agent and investigated the effects of irradiation on the porosity, translucency, and mechanical properties of veneering porcelain. Sixty discs (diameter 3.5 × 2.0 mm) of veneering porcelain for Y-TZP frameworks (VM9, VITA Zahnfabrik) were sintered and had one of their faces mirror polished. The specimens were divided into six groups (n=10/group) according to surface treatment, as follows: no treatment–control; auto-glaze in furnace following manufacturer's instructions (G); and CO2 laser (45 or 50 W/cm2) applied for four or five minutes (L45/4, L45/5, L50/4, L50/5). Optical microscopy (Shimadzu, 100×) was conducted and the images were analyzed with Image J software for the determination of the following porosity parameters: area fraction, average size, and Feret diameter. The translucency parameter studied was masking ability, determined by color difference (ΔE) over black and white backgrounds (CM3370d, Konica Minolta). Microhardness and fracture toughness (indentation fracture) were measured with a Vickers indenter (HMV, Shimadzu). Contact atomic force microscopy (AFM) (50 × 50 μm2, Nanoscope IIIA, Veeco) was performed at the center of one sample from each group, except in the case of L45/5. With regard to porosity and translucency parameters, auto-glazed and laser-irradiated specimens presented statistical similarity. The area fraction of the surface pores ranged between 2.4% and 5.4% for irradiated specimens. Group L50/5 presented higher microhardness when compared to the G group. The higher (1.1) and lower (0.8) values for fracture toughness (MPa.m1/2) were found in laser-irradiated groups (L50/4 and L45/4, respectively). AFM performed after laser treatment revealed changes in porcelain surface profile at a submicrometric scale, with the presence of elongated peaks and deep valleys.

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Sabatini, C. "Color Stability Behavior of Methacrylate-based Resin Composites Polymerized with Light-emitting Diodes and Quartz-Tungsten-Halogen." Operative Dentistry 40, no. 3 (May 1, 2015): 271–81. http://dx.doi.org/10.2341/14-080-l.

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SUMMARY Despite significant developments in improving the optical properties of resin composite materials, their color stability remains a challenge. This study aimed to evaluate the shade stability of light-polymerized, methacrylate-based resin composites with different filler particle composition (microfill, minifill, nanohybrids, and microhybrids) polymerized with quartz-tungsten-halogen (QTH) and light-emitting diodes (LED). Methods and Materials Composite discs were fabricated from Tetric EvoCeram, Premise, Artiste, and Beautifil II (nanohybrids); Filtek Supreme Plus and Vit-l-escence (microhybrids); Heliomolar (microfill); and Estelite Sigma Quick (minifill) using a Teflon mold. The specimens were irradiated either with QTH (Elipar 2500; 600 mW/cm2) for 40 seconds or with LED (Bluephase G2; 1200 mW/cm2) for 20 seconds. Color parameters were measured with a colorimeter before and after polymerization and at 24 hours, one week, one month, and three months. Color change was calculated among the different storage periods. Results There was a significant effect of the composite, time, and their interaction (p<0.001) but no effect of the polymerization unit on the color stability. Color changes immediately after polymerization and at 24 hours (4.22 and 3.88 for LED; and 4.08 and 3.82 for QTH) were not significantly different from each other but were both significantly higher than changes after one week (0.96 and 0.78), one month (1.12 and 1.02), and three months (1.27 and 1.11) for LED and QTH, respectively (p<0.001). Conclusions Color changes were observed for all the materials that were dependent on the type of composite but not on the polymerization unit. These color shifts took place primarily immediately after polymerization and after 24 hours and were additive in nature.

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Par, M., O. Gamulin, D. Marovic, E. Klaric, and Z. Tarle. "Raman Spectroscopic Assessment of Degree of Conversion of Bulk-Fill Resin Composites – Changes at 24 Hours Post Cure." Operative Dentistry 40, no. 3 (May 1, 2015): E92—E101. http://dx.doi.org/10.2341/14-091-l.

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SUMMARY Objective The aim of this study was to determine degree of conversion (DC) of solid and flowable bulk-fill composites immediately and after 24 hours and investigate the variations of DC at surface and depths up to 4 mm. Materials and Methods Eight bulk-fill composites (Tetric EvoCeram Bulk Fill [shades IVA and IVB], Quixfil, X-tra fil, Venus Bulk Fill, X-tra Base, SDR, Filtek Bulk Fill) were investigated, and two conventional composites (GrandioSO, X-Flow) were used as controls. The samples (n = 5) were cured for 20 seconds with irradiance of 1090 mW/cm2. Raman spectroscopic measurements were made immediately after curing on sample surfaces and after 24 hours of dark storage at surface and at incremental depths up to 4 mm. Mean DC values were compared using repeated measures analysis of variance (ANOVA) and t-test for dependent samples. Results Surface DC values immediately after curing ranged from 59.1%-71.8%, while the 24-hour postcure values ranged from 71.3%-86.1%. A significant increase of DC was observed 24 hours post cure for all bulk-fill composites, which amounted from 11.3% to 16.9%. Decrease of DC through depths up to 4 mm varied widely among bulk-fill composites and ranged from 2.9% to 19.7%. Conclusions All bulk-fill composites presented a considerable 24-hour postcure DC increase and clinically acceptable DC at depths up to 4 mm. Conventional control composites were sufficiently cured only up to 2 mm, despite significant postcure polymerization.

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Pereira, RD, ADCM Valdívia, AA Bicalho, SD Franco, D. Tantbirojn, A. Versluis, and CJ Soares. "Effect of Photoactivation Timing on the Mechanical Properties of Resin Cements and Bond Strength of Fiberglass Post to Root Dentin." Operative Dentistry 40, no. 5 (September 1, 2015): E206—E221. http://dx.doi.org/10.2341/14-115-l.

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SUMMARY Objectives This study tested the hypothesis that photoactivation timing and resin cement affect mechanical properties and bond strength of fiberglass posts to root dentin at different depths. Methods Fiberglass posts (Exacto, Angelus) were luted with RelyX Unicem (3M ESPE), Panavia F 2.0 (Kuraray), or RelyX ARC (3M ESPE) using three photoactivation timings: light curing immediately, after three minutes, or after five minutes. Push-out bonding strength, PBS (n=10) was measured on each root region (coronal, middle, apical). The elastic modulus (E) and Vickers hardness (VHN) of the cement layer along the root canal were determined using dynamic indentation (n=5). A strain-gauge test was used to measure post-gel shrinkage of each cement (n=10). Residual shrinkage stress was assessed with finite element analysis. Data were analyzed with two-way analysis of variance in a split-plot arrangement and a Tukey test (α=0.05). Multiple linear regression analysis was used to determine the influence of study factors. Results The five-minute delay photoactivation timing significantly increased the PBS for all resin cements evaluated. The PBS decreased significantly from coronal to apical root canal regions. The mean values for E and VHN increased significantly with the delayed photoactivation for RelyX Unicem and decreased from coronal to apical root regions for all resin cements with the immediate-curing timing. Conclusions The PBS of fiber posts to root dentin, E, and VHN values were affected by the root canal region, photoactivation timing, and resin cement type. Shrinkage stress values decreased gradually with delayed photoactivation for all the cements.

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Kalavacharla, VK, NC Lawson, LC Ramp, and JO Burgess. "Influence of Etching Protocol and Silane Treatment with a Universal Adhesive on Lithium Disilicate Bond Strength." Operative Dentistry 40, no. 4 (June 1, 2015): 372–78. http://dx.doi.org/10.2341/14-116-l.

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SUMMARY Objectives To measure the effects of hydrofluoric acid (HF) etching and silane prior to the application of a universal adhesive on the bond strength between lithium disilicate and a resin. Methods and Materials Sixty blocks of lithium disilicate (e.max CAD, Ivoclar Vivadent) were sectioned into coupons and polished. Specimens were divided into six groups (n=10) based on surface pretreatments, as follows: 1) no treatment (control); 2) 5% HF etch for 20 seconds (5HF); 3) 9.5% HF etch for 60 seconds (9.5HF); 4) silane with no HF (S); 5) 5% HF for 20 seconds + silane (5HFS); and 6) 9.5% HF for 60 seconds + silane (9.5HFS). All etching was followed by rinsing, and all silane was applied in one coat for 20 seconds and then dried. The universal adhesive (Scotchbond Universal, 3M ESPE) was applied onto the pretreated ceramic surface, air thinned, and light cured for 10 seconds. A 1.5-mm-diameter plastic tube filled with Z100 composite (3M ESPE) was applied over the bonded ceramic surface and light cured for 20 seconds on all four sides. The specimens were thermocycled for 10,000 cycles (5°C-50°C/15 s dwell time). Specimens were loaded until failure using a universal testing machine at a crosshead speed of 1 mm/min. The peak failure load was used to calculate the shear bond strength. Scanning electron microscopy images were taken of representative e.max specimens from each group. Results A two-way analysis of variance (ANOVA) determined that there were significant differences between HF etching, silane treatment, and the interaction between HF and silane treatment (p<0.01). Silane treatment provided higher shear bond strength regardless of the use or concentration of the HF etchant. Individual one-way ANOVA and Tukey post hoc analyses were performed for each silane group. Shear bond strength values for each etch time were significantly different (p<0.01) and could be divided into significantly different groups based on silane treatment: no silane treatment: 0 HF < 5% HF < 9.5% HF; and RelyX silane treatment: 0 HF < 5% HF and 9.5% HF. Conclusions Both HF and silane treatment significantly improved the bond strength between resin and lithium disilicate when used with a universal adhesive.

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St Germain, HA, and TH St Germain. "Shear Bond Strength of Porcelain Veneers Rebonded to Enamel." Operative Dentistry 40, no. 3 (May 1, 2015): E112—E121. http://dx.doi.org/10.2341/14-123-l.

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SUMMARY In this laboratory research, shear bond strength (SBS) and mode of failure of veneers rebonded to enamel in shear compression were determined. Three groups (A, B, and C; n=10 each) of mounted molar teeth were finished flat using wet 600-grit silicon carbide paper, and 30 leucite-reinforced porcelain veneers (5.0 × 0.75 mm) were air abraded on the internal surface with 50 μm aluminum oxide, etched with 9.5% hydrofluoric acid, and silanated. The control group (A) veneer specimens were bonded to enamel after etching with 37% phosphoric acid using bonding resin and a dual cure resin composite cement. Groups B and C were prepared similarly to group A with the exception that a release agent was placed before the veneer was positioned on the prepared enamel surface and the resin cement was subsequently light activated. The debonded veneers from groups B and C were placed in a casting burnout oven and heated to 454°C/850°F for 10 minutes to completely carbonize the resin cement and stay below the glass transition temperature (Tg) of the leucite-reinforced porcelain. The recovered veneers were then prepared for bonding. The previously bonded enamel surfaces in group B were air abraded using 50 μm aluminum oxide followed by 37% phosphoric acid etching, while group C enamel specimens were acid etched only. All specimens were thermocycled between 5°C and 55°C for 2000 cycles using a 30-second dwell time and stored in 37°C deionized water for 2 weeks. SBS was determined at a crosshead speed of 1.0 mm/min. SBS results in MPa for the groups were (A) = 20.6±5.1, (B) = 18.1±5.5, and (C) = 17.2±6.1. One-way analysis of variance indicated that there were no significant interactions (α=0.05), and Tukey-Kramer post hoc comparisons (α=0.05) detected no significant pairwise differences. An adhesive mode of failure at the enamel interface was observed to occur more often in the experimental groups (B = 40%, C = 50%). Rebonding the veneers produced SBS values that were not significantly different from the control group. Also, no significant difference in SBS values were observed whether the debonded enamel surface was air abraded and acid etched or acid etched only.

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Sundfeld Neto, D., LZ Naves, AR Costa, AB Correr, S. Consani, GA Borges, and L. Correr-Sobrinho. "The Effect of Hydrofluoric Acid Concentration on the Bond Strength and Morphology of the Surface and Interface of Glass Ceramics to a Resin Cement." Operative Dentistry 40, no. 5 (September 1, 2015): 470–79. http://dx.doi.org/10.2341/14-133-l.

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SUMMARY The purpose of this study was to evaluate the influence of various concentrations of hydrofluoric acid (HF) on the surface/interface morphology and μ–shear bond strength (μSBS) between IPS Empress Esthetic (EST) (Ivoclar Vivadent) and IPS e.max Press (EMX) (Ivoclar Vivadent) ceramics and resin cement. Ceramic blocks were divided into 12 groups for each kind of ceramic. Six different HF concentrations were evaluated: 1%, 2.5%, 5%, 7.5%, 10%, and 15%. All groups were silanated after etching, and half of the specimens within each group received a thin layer of unfilled resin (UR). Three resin cement cylinders were prepared on each ceramic block for μSBS testing. The specimens were stored in distilled water at 37°C for 24 hours. The μSBS test was carried out in a universal testing machine at a crosshead speed of 0.5 mm/min until fracture. The data were submitted to three-way analysis of variance and multiple comparisons were performed using the Tukey post hoc test (p<0.05). The etched surfaces and bonded interfaces were evaluated using scanning electron microscopy. μSBS means (MPa) for 1%, 2.5%, 5%, 7.5%, 10%, and 15% HF concentrations were, respectively, 25.2, 27.2, 30.1, 31.4, 33.3, and 31.8. μSBS means with or without UR application measured 32.24 and 27.4, respectively; EST and EMX measured 29.8 and 29.9, respectively. For the HF concentrations, 10% and 15% showed higher μSBS means than did 1% and 2.5% (p<0.05); 7.5% was higher than 1% (p<0.05); and no statistical differences were found among the other concentrations (p>0.05). When evaluating UR, μSBS mean was significantly higher and better infiltration was observed on the etched surfaces. No statistical difference was found between the ceramics. The HF concentration and UR influenced the bond strength and surface/interface morphology.

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El-Deeb, HA, O. Badran, and EH Mobarak. "One-year Adhesive Bond Durability to Coronal and Radicular Dentin Under Intrapulpal Pressure Simulation." Operative Dentistry 40, no. 5 (September 1, 2015): 540–47. http://dx.doi.org/10.2341/14-134-l.

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SUMMARY Objective To evaluate the microtensile bond strength (μTBS) of different adhesives to coronal vs radicular dentin after one year of storage in artificial saliva and under intrapulpal pressure (IPP) simulation. Methods and Materials Roots of 36 freshly extracted premolars were sectioned 5 mm apical to the cemento-enamel junction and pulp tissue was removed. Buccal enamel and cementum were trimmed to obtain standardized flat dentin surfaces. Specimens were divided into three groups (n=12/group) according to the adhesive strategies utilized: a two-step etch-and-rinse adhesive; a two-step self-etch adhesive; and a single-step self-etch adhesive. Adhesives and resin composite were applied to coronal and radicular dentin while the specimens were subjected to IPP simulation. After curing, specimens were stored in artificial saliva at 37°C in a specially constructed incubator while the IPP was maintained for either 24 hours or one year prior to testing. Bonded specimens were sectioned into sticks with a cross section of 0.8 ± 0.01 mm2 and subjected to μTBS testing. Data were statistically analyzed using multi-way analysis of variance (ANOVA) with repeated measures; one-way ANOVA tests; and Bonferroni post hoc test (p<0.05). Failure modes were determined using a scanning electron microscope at 100× magnification. Results ANOVA results revealed a statistically significant effect for the adhesive strategy (p<0.001) and storage period (p<0.001) as well as for their interaction (p=0.024) on the μTBS. However, dentin substrate and its interactions revealed no significant effects. For both dentin substrates, the two-step self-etch adhesive revealed statistically significantly higher μTBS values than did the other two adhesives after 24 hours and one year of storage. After one-year storage, a significant decrease in bond strength values of all tested adhesives occurred with both dentin substrates. Modes of failure were mainly adhesive and mixed. Conclusions Adhesives were not sensitive to structural differences between coronal and radicular dentin even after one year of storage under IPP simulation. However, all tested adhesive systems strategies were sensitive to storage.

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Alomari, QD, M. Qudiemat, ME Khalaf, and Y. Al-Tarakemah. "The Effect of Combining Radiographs and DIAGNOdent With Visual Examination on Detection and Treatment Decisions of Noncavitated Occluso-dentinal Caries." Operative Dentistry 40, no. 3 (May 1, 2015): 313–21. http://dx.doi.org/10.2341/14-138-l.

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SUMMARY The aim of this laboratory study was to evaluate the effectiveness of incorporating radiographic examination and DIAGNOdent with visual examination for the detection and treatment of noncavitated occluso-dentinal caries. Four examiners examined the occlusal surfaces of 160 extracted posterior teeth. Teeth were examined three times with a one-month interval in between. The first examination was visual (V), the second examination was visual with radiograph (VR), and the third examination was visual with radiograph and DIAGNOdent (VRD). Examiners were asked to detect the presence of caries (if any) and identify the extent of caries (if present; ie, enamel or dentin). The examiners were also asked to choose a treatment for each tooth. The examined teeth were later sectioned, and the presence of caries was charted as 0 = no caries, 1 = caries confined to enamel, 2 = caries in the outer dentin, and 3 = caries in the inner dentin. Sensitivity, specificity, area under the curve (Az values), rank correlation coefficient, interexaminer reproducibility, and McNemar χ2 tests were calculated. VR had statistically higher specificity and lower sensitivity than V and VRD. The means of Az values ranged from 0.58 to 0.63, with no statistical difference between the three examinations (p>0.05). The means of the rank correlation coefficients with histology for detection of dentinal caries were 0.48, 0.23, and 0.44 using V, VR, and VRD, respectively. Interexaminer reproducibility was best for V alone. The percentages of teeth indicated for restorative treatment were 31%, 33%, and 41% using V, VR, and VRD, respectively. The percentages of teeth correctly treated according to histology were 69.4%, 70.0%, and 67.5% using V, VR, and VRD, respectively. There was no difference in the accuracy of treatment decisions between the three examination points (p>0.05). The addition of radiographs and DIAGNOdent to visual examination did not have a significant effect on the improvement of the detection or treatment decisions of examiners of noncavitated occluso-dentinal carious lesions.

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Melo, RM, ROA Souza, E. Dursun, EBC Monteiro, LF Valandro, and MA Bottino. "Surface Treatments of Zirconia to Enhance Bonding Durability." Operative Dentistry 40, no. 6 (November 1, 2015): 636–43. http://dx.doi.org/10.2341/14-144-l.

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Abstract:

SUMMARY This article reviewed the surface treatments used most often to improve adhesion between zirconia and adhesive cements, focusing on their capacity to provide long-term bonding. Traditional and new treatments for zirconia bonding were searched. Some new treatments were discussed along with topographical views of the modified zirconia. New methods, such as selective infiltration etching and the low-fusing glassy porcelain application are promising, but more research is needed.

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50

Klaric, E., M. Rakic, I. Sever, O. Milat, M. Par, and Z. Tarle. "Enamel and Dentin Microhardness and Chemical Composition After Experimental Light-activated Bleaching." Operative Dentistry 40, no. 4 (June 1, 2015): E132—E141. http://dx.doi.org/10.2341/14-148-l.

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Abstract:

SUMMARY Objectives To evaluate 1) the influence of five bleaching agents (with additional light activation) on enamel and dentin surface microhardness and chemical composition and 2) the remineralizing potential of artificial saliva and amorphous calcium phosphate (ACP). Methods and Materials The study was conducted on 125 human third molars dissected into quarters for separate enamel and dentin measurements. The bleaching process was performed with 38% and 25% hydrogen peroxide (HP) and 30%, 16%, and 10% carbamide peroxide (CP) gels two times for 15 minutes each time. All bleaching gels were tested alone and in combination with ZOOM2, light-emitting diode (LED), organic LED, and femtosecond laser. A total of 25 bleaching combinations (n=10) were evaluated. Microhardness was measured by a Vickers diamond. Chemical analysis was performed using energy-dispersive X-ray spectroscopy. Results Bleaching agents used in the absence of light activation caused a significant reduction in enamel and dentin surface microhardness (p<0.001), ranging from 8% for 16% CP to 40% for 25% HP. The effects of different light activations were negligible. After two-week treatment with ACP and artificial saliva, maximum deviation from baseline microhardness was just 3%. Such treatment increased the concentrations of calcium, phosphorus, and fluorine. Conclusions An increase in peroxide concentration and gel acidity negatively affected microhardness and concentrations of calcium and phosphorus in enamel and dentin. ACP and artificial saliva stimulated the remineralization of hard tissues.

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Journal articles on the topic 'L 14'

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