ABSTRACT Nuchal Translucency as a method of First Trimester Screening for Aneuploidy in a South African population Background Chromosomal abnormalities constitute 15% of congenital abnormalities and 50% of pregnancy losses. Twenty-five percent of these will be Trisomy 21. Down’s syndrome has a birth incidence of 2 per 1000 and constitutes 25% of severe mental handicap in the developed world. Whereas the risk assessment focuses on Trisomy 21, the fetuses that screen positive are also known to contain other defects, which include anomalies such as cardiac defects, diaphragmatic hernias, neuromuscular disorders, and rare genetic syndromes. Objective To determine the effectiveness of nuchal translucency (NT) screening in predicting aneuploidy and structural abnormalities in a South African population Setting Chris Hani Baragwanath Hospital Fetal Medicine Unit Study design Descriptive Study Methodology The Fetal Medicine Unit database was reviewed and the records of patients who had undergone NT screening between July 2003 and July 2005 were retrieved. There were no exclusions. An adjusted risk was derived from the combination of age-related risk and the risk derived from nuchal translucency screening. A positive screen was denoted by an adjusted risk of more than 1/300 and a negative screen was denoted by an adjusted risk of less than 1/300. Results A total of 428 patients had first trimester screening during this period. Thirteen patients (3%) were lost to follow up. Of the 415 cases that were analyzed, 57 patients screened positive and 356 patients screened negative. In addition, 2 fetuses with acrania were detected. The mean age for both groups of patients was 30.1 years. The crown-rump length of fetuses with a positive screen was statistically significantly shorter than fetuses that screened negative. Of the 57 patients that screened positive 24 elected to have chorionic villus sampling (CVS) which resulted in the detection of 6 chromosomal abnormalities and 2 structural abnormalities. Of the remaining 356 patients, who had screened negative, 2 had an increased adjusted risk, and one chromosomal abnormality was detected in this group. Of the remaining 354 patients, 8 elected to have CVS because of a previous history of chromosomal abnormality. All of them proved to be normal. Conclusions The use of such screening has enabled prenatal karyotyping to be focused on pregnancies at highest risk for chromosomal abnormalities regardless of age.

Orientador: Welingtom Dinelli / Banca: José Roberto Cury Saad / Banca: Regina Guenka Palma Dibb / Resumo: O objetivo deste estudo foi avaliar in vitro a translucidez da resina composta, em função do efeito do selamento superficial; da exposição à fumaça de cigarro e da escovação. Para tanto, 40 corpos-de-prova (10 mm X 1 mm) foram confeccionados com resina composta Filtek Z250 divididos aleatoriamente em 4 grupos (n=10), sendo: G1 - controle (saliva artificial e sem selante); G2 - saliva artificial e com selante (Protect-it!); G3 - cigarro e sem selante e G4 - cigarro e com selante. Os espécimes foram submetidos à avaliação da translucidez em diferentes tempos: T1: imediatamente após a confecção; T2: após o polimento; T3: após o selamento (G2 e G4); T4: após o 1º tratamento (10 dias imersos em saliva artificial ou manchados por 200 cigarros); T5: após serem submetidos a 1ª escovação (850 ciclos); T6: após o 2º tratamento (10 dias imersos em saliva artificial ou manchados por 200 cigarros); T7: após serem submetidos a 2ª escovação (850 ciclos); T8: após o 3º tratamento (10 dias imersos em saliva artificial ou manchados por 200 cigarros); T9: após serem submetidos a 3ª escovação (850 ciclos). Os valores de translucidez foram obtidos no aparelho JOUAN e analisados estatisticamente pelos testes de Mann-Whitney, Kruskal-Wallis, Friedman, seguidos da Análise de Variância e teste de Tukey. Observou-se que o selamento não provocou alteração significativa da translucidez dos espécimes e que após a 1ª escovação ocorreu aumento significativo, mantendo-se constante nos G1 e G2, e para os G3 e G4 o cigarro provocou severo manchamento que foi removido parcialmente pela escovação. Concluindo que o selamento não promoveu melhora na translucidez com o tempo e nem protegeu contra manchamento, sendo que a escovação não restabeleceu a translucidez. / Abstract: The aim of this study was to assess in vitro the translucency of the composite resin, in function of the effect of the surface sealing; after the exposition to the cigarette smoke and of the toothbrushing. Forty specimens (10mm X 1mm) they were made with composite resin Filtek Z250 divided into 4 groups (n = 10), being: G1 - it controls (it artificial saliva and without sealant); G2 - it artificial saliva and with sealant (Protect-it!); G3 - cigarette and without sealant and G4 - cigarette and with sealant. The specimens were submitted to the evaluation of the translucency in different times: T1: immediately after the making; T2: after the polishing; T3: after the sealing (G2 and G4); T4: after the 1st treatment (10 submerged days in artificial saliva or spotted for 200 cigarettes); T5: after they be submitted to 1st toothbrushing (850 cycles); T6: after the 2nd treatment (10 submerged days in artificial saliva or spotted for 200 cigarettes); T7: after they be submitted to 2nd toothbrushing (850 cycles); T8: after the 3rd treatment (10 submerged days in artificial saliva or spotted for 200 cigarettes); T9: after they be submitted to 3rd toothbrushing (850 cycles). The translucency values were obtained in the JOUAN apparel and analyzed by the tests of Mann-Whitney, Kruskal-Wallis and Friedman, following by the Analysis of Variance and test of Tukey. It was observed that the sealing didn't provoke significant alteration of the translucency of the specimens and that after to 1st toothbrushing it happened significant increase, staying constant in G1 and G2, and for G3 and G4 the cigarette provoked severe staining that was removed partially by the toothbrushing. Concluding that the sealing didn't promote improvement in the translucency with the time and nor it protected against staining, and the toothbrushing didn't reestablish the translucency. / Mestre

Objective: To compare the translucency of six different porcelains indicated for veneers, with various shades and opacities. Methods: 13mm diameter and 0.7mm thickness discs were fabricated for the following porcelains (A1 shade; n=5): Empress Esthetic (EE), e.maxPress (EP), InLine (IL) (Ivoclar Vivadent); VITA PM9 (VPM), Vitablocks MarkII (VMII) (Vita Zahnfabrik); Kavo Everest G-Blank (KEG) (KaVo Dental GmbH) and Lava Zirconia (LZ) (3M ESPE). IL and LZ respectively served as positive and negative controls. Groups with different shades (BL2, BL4, A1, B1), as well as high (HT) and low translucencies (LT), were fabricated for e.maxPress. The luminous reflectance (Y) and color coordinates (CIE L*a*b*) were measured with a colorimeter (CIE illuminant D65, 2-degree observer function) with the specimens placed on black and white backgrounds. Contrast ratios (CR = YB/YW) and translucency parameters (TP= [(LB* - LW*)2 + (aB* - aW*)2 + (bB* - bW*)2 ]1/2) were calculated. One-way ANOVA and post-hoc Tukey's HSD tests were used to analyze the data (α = 0.05). Results: Statistically significant differences in CR and TP were found among porcelains (P < .0001). The CR means in order of decreasing translucency were: VPM (0.15) > VMII (0.24), IL (0.25), KEG (0.26) > EP HTB1 (0.32), EE (0.34) > EP HTA1 (0.37), EP HTBL4 (0.37) > EP HTBL2 (0.43), EP LTA1 (0.47) > LZ (0.73). The TP means in order of decreasing translucency were: VPM (40.34) > VMII (33.66), KEG (33.52), IL (32.44) > EP HTB1 (27.96), EE (27.64) > EP HTA1 (26.59), EP HTBL4 (26.14) > EP HTBL2 (22.70), EP LTA1 (21.35) > LZ (10.43). Translucency of conventional feldspathic porcelain was comparable to that of machinable feldspathic porcelain. Pressable feldspathic porcelain presented the greatest translucency. Shade and thickness influenced lithium disilicate porcelain translucency. Conclusion: Various ceramics systems designed for porcelain veneers present various degrees of translucency.

No description available.

STATEMENT OF THE PROBLEM: There is no international standardized guidance to quantify translucency in dentistry. Numerous non-standardized terms are being used to describe the degree of translucency by the manufacturers. This makes it hard for the dental community to find definite and compare easy information. PURPOSE: To attempt exploring the standardization of the quantification of translucency in dental ceramics by comparing various optical property measurements including Contrast Ratio (CR), Translucency Parameter (TP) and transmission, gloss and surface roughness and by investigating the relationship between thickness, polish grade and translucency. MATERIAL AND METHODS: Four monolithic zirconia materials were used in this study; VITA-YZ Translucent, High Translucent, Super Translucent and Extra Translucent. IPS e.max CAD HT was used as a control. Specimens for each of these materials were prepared in 125 µm, 70 µm, 15 µm, and 0.5 µm polished surface in the following thicknesses: 1.00 mm, 0.75 mm, 0.50 mm and 0.35 mm thickness. Each group contained 10 specimens and the following tests were completed: transmission, CR and TP using a X-rite Ci6700 spectrophotometer, surface roughness by profilometer and gloss index by a glossmeter. Data was analyzed by using two-way ANOVA for different groups and Tukey’s for paired groups. Coefficient of absorption and loss of reflectance ratio were calculated. RESULTS: Reducing thickness and increasing polishing grade increase translucency. Material type, thickness and polishing grade significantly affected the translucency. A strong positive (r=0.99) linear correlation between transmission and TP was determined and these have a strong negative (r=-0.99) linear correlation with CR. CONCLUSION: Thickness, polishing grade and material type are major contributing factors to the translucency of ceramics. E.max HT is significantly more translucent than zirconia. Transmission is viable to be used as a standardized measurement of translucency with standardized material settings of 1mm thickness and optical polishing (polishing grade of 0.5 µm or its equivalent).

No description available.

Made available in DSpace on 2014-06-11T19:24:08Z (GMT). No. of bitstreams: 0 Previous issue date: 2004-02-09Bitstream added on 2014-06-13T19:10:19Z : No. of bitstreams: 1 takeuchi_cyg_me_arafo.pdf: 548399 bytes, checksum: dc80caffca8640c92d69a902fa0d9a40 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O objetivo deste estudo foi avaliar in vitro a translucidez da resina composta, em função do efeito do selamento superficial; da exposição à fumaça de cigarro e da escovação. Para tanto, 40 corpos-de-prova (10 mm X 1 mm) foram confeccionados com resina composta Filtek Z250 divididos aleatoriamente em 4 grupos (n=10), sendo: G1 - controle (saliva artificial e sem selante); G2 - saliva artificial e com selante (Protect-it!); G3 - cigarro e sem selante e G4 - cigarro e com selante. Os espécimes foram submetidos à avaliação da translucidez em diferentes tempos: T1: imediatamente após a confecção; T2: após o polimento; T3: após o selamento (G2 e G4); T4: após o 1º tratamento (10 dias imersos em saliva artificial ou manchados por 200 cigarros); T5: após serem submetidos a 1ª escovação (850 ciclos); T6: após o 2º tratamento (10 dias imersos em saliva artificial ou manchados por 200 cigarros); T7: após serem submetidos a 2ª escovação (850 ciclos); T8: após o 3º tratamento (10 dias imersos em saliva artificial ou manchados por 200 cigarros); T9: após serem submetidos a 3ª escovação (850 ciclos). Os valores de translucidez foram obtidos no aparelho JOUAN e analisados estatisticamente pelos testes de Mann-Whitney, Kruskal-Wallis, Friedman, seguidos da Análise de Variância e teste de Tukey. Observou-se que o selamento não provocou alteração significativa da translucidez dos espécimes e que após a 1ª escovação ocorreu aumento significativo, mantendo-se constante nos G1 e G2, e para os G3 e G4 o cigarro provocou severo manchamento que foi removido parcialmente pela escovação. Concluindo que o selamento não promoveu melhora na translucidez com o tempo e nem protegeu contra manchamento, sendo que a escovação não restabeleceu a translucidez. / The aim of this study was to assess in vitro the translucency of the composite resin, in function of the effect of the surface sealing; after the exposition to the cigarette smoke and of the toothbrushing. Forty specimens (10mm X 1mm) they were made with composite resin Filtek Z250 divided into 4 groups (n = 10), being: G1 - it controls (it artificial saliva and without sealant); G2 - it artificial saliva and with sealant (Protect-it!); G3 - cigarette and without sealant and G4 - cigarette and with sealant. The specimens were submitted to the evaluation of the translucency in different times: T1: immediately after the making; T2: after the polishing; T3: after the sealing (G2 and G4); T4: after the 1st treatment (10 submerged days in artificial saliva or spotted for 200 cigarettes); T5: after they be submitted to 1st toothbrushing (850 cycles); T6: after the 2nd treatment (10 submerged days in artificial saliva or spotted for 200 cigarettes); T7: after they be submitted to 2nd toothbrushing (850 cycles); T8: after the 3rd treatment (10 submerged days in artificial saliva or spotted for 200 cigarettes); T9: after they be submitted to 3rd toothbrushing (850 cycles). The translucency values were obtained in the JOUAN apparel and analyzed by the tests of Mann-Whitney, Kruskal-Wallis and Friedman, following by the Analysis of Variance and test of Tukey. It was observed that the sealing didn't provoke significant alteration of the translucency of the specimens and that after to 1st toothbrushing it happened significant increase, staying constant in G1 and G2, and for G3 and G4 the cigarette provoked severe staining that was removed partially by the toothbrushing. Concluding that the sealing didn't promote improvement in the translucency with the time and nor it protected against staining, and the toothbrushing didn’t reestablish the translucency.

This project’s origin lies in the clash of translucency and opacity in relation to color, knit and the body. This clash is explored through manipulated knitwear. By manipulating knitwear the interaction between opacity, translucency and the body inside becomes the vital core of this collection work. The main tool to manipulate the knit and to push the effect of translucency is the textile printing technique „devoré“.

This study’s objective was to evaluate repetitive firing cycles’ effects on the translucency, light’s absorption coefficient, and flexural strength of zirconia-reinforced lithium silicate ceramics. Two zirconia-reinforced lithium silicate ceramics and one lithium disilicate glass-ceramic were tested. Blocks of all materials were sectioned into tiles with different thicknesses and subjected to up to five firing cycles using the firing schedule indicated in the manufacturer’s user instructions. Light transmission ratio (T) and absorption coefficients were determined using a spectrophotometer. Further, bars were sectioned from blocks of all materials and tested for three-point-bend flexural strength using a Universal Testing Machine (Instron), and flexural strength was calculated from load at failure. Factorial ANOVA and Tukey’s HSD tests were conducted to analyze light transmission and flexural strength, while regression was used to analyze the absorption coefficient. Weibull parameters and fractographic analysis also were investigated. The results showed that repetitive firing cycles reduced e.max® and Vita Suprinity’s® translucency, but not that of Celtra® Duo, which showed no significant difference. All materials of greater thickness exhibited less translucency, and e.max® CAD had the highest mean light transmission; however, it was not significantly different than Celtra® Duo. Repetitive firing cycles showed more absorption coefficient of light with Vita Suprinity® and e.max®, except for Celtra® Duo, which showed no difference. Vita Suprinity® showed the highest absorption coefficient; however, it was not significantly different than e.max® CAD. Repetitive firing cycles had no significant effect on flexural strength. High and low flexural strength samples for all materials showed similar characteristics with respect to crack propagation patterns, and fracture origins. In conclusion, repetitive firing cycles decreased both e.max® and Vita Suprinity’s® translucency significantly. Repetitive firing cycles increased e.max® and Vita Suprinity’s® absorption coefficient significantly, particularly at shorter wavelengths. Repetitive firing cycles did not increase flexural strength statistically significantly. Vita Suprinity® showed an inherent and more homogeneous flaw-distribution in the first two firing cycles compared to the distribution of flaws in the other two materials.

No description available.