Indiana University-Purdue University Indianapolis (IUPUI)

<p>The aim of this laboratory based study is to assess the efficiency of a tooth bleaching agent by measuring the degree of color change with a spectrophotometer (Konica Minolta, CM 2600d) and not by the usual subjective visual guide methods. Objectives of the study are: To determine tooth shade with a spectrophotometer prior to staining the tooth (baseline). To determine which insult causes the most discoloration numerically. To measure the efficiency of the bleaching agent used in the study with periodic color change pectrophotometer readings.&nbsp / To assess if the baseline tooth shade can be regained by the bleaching agent.</p>

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<p>The aim of this laboratory based study is to assess the efficiency of a tooth bleaching agent by measuring the degree of color change with a spectrophotometer (Konica Minolta, CM 2600d) and not by the usual subjective visual guide methods. Objectives of the study are: To determine tooth shade with a spectrophotometer prior to staining the tooth (baseline). To determine which insult causes the most discoloration numerically. To measure the efficiency of the bleaching agent used in the study with periodic color change pectrophotometer readings.&nbsp / To assess if the baseline tooth shade can be regained by the bleaching agent.</p>

Consumers and Canadian poultry processors were interviewed to understand the overall perception of bone-in chicken meat and to gain insight on the defect of black bone discoloration, a color defect that appears in cooked bone-in chicken. Through the consumer science technique of laddering, food safety, eating quality, price, health and convenience were revealed as the most important values associated with chicken meat. Poultry processors agreed upon the importance of food safety. Black bone discoloration did not greatly influence consumer acceptance of broiler meat, nor did it appear to negatively impact the poultry industry as complaints were reported rarely. Modifying broiler bone growth rate through dietary treatments did not significantly (P>0.05) alter the sensory properties of the meat or reduce the incidence of discoloration. Overall, black bone discoloration is not perceived as a major problem for the poultry industry in Canada. In order to maintain consumer demand, poultry producers should focus on the food safety aspect of their products. / Food Science and Technology

Magister Scientiae Dentium - MSc(Dent) / Summary: Aim: The aim of this laboratory study is to assess the efficacy of a tooth bleaching agent by evaluating the degree of color change with the use of a spectrophotometer and not by the usual subjective, visual methods. Methodology: Twenty specimens of human teeth will be collected, polished and divided into two groups. A baseline color measurement by the CIE L* a* b* with a spectrophotometer against a white background will be taken before one group is immersed in coffee and the other in red wine for two weeks. Bleaching of the specimens will be done according to manufacturer’s instructions for two weeks. Color readings will be taken before bleaching, weekly during bleaching and 1 and 2 weeks after the bleaching treatment. Color change (ΔE) will be calculated mathematically as Δ E = [ (Δ L*)2 + (Δ a*)2 + (Δ b*)2 ]1/2. An observation of whether the baseline color reading will be regained by the bleaching process will be made. Results: Data collected will be recorded on an Excel spreadsheet. Advice from a qualified statistician will be sought to analyze the data. Results will be discussed in comparison with the existing literature on this subject. / South Africa

Discolorations in highly valued southern hardwood species have been a costly problem for the U.S. forest products industry since its beginning. Both microbial (fungi) and non-microbial (enzyme-mediated) sapstain problems are more prevalent in the southeast than in other regions, so preventive measure must be done to keep hardwood logs and lumber discolorationree. Six full-scale field trials were conducted along the Mississippi River from Yokena, MS to Ripley, TN between March to October 2007. The basis for the research was a belief that discolorations that affect southern hardwood logs can be controlled by various techniques such as log end coating, inventory management, and combinations of each. These tests revealed important information such as chemical compatibility issues, storage facility upkeep, workforce development through scheduling and communication, and other items were found in this research to keep southern hardwood logs and lumber from discoloring.

Syfte: Syftet med denna studie var att undersöka resistens mot marginala missfärgningar av en adhesivt cementerad keram till emalj beroende på typ av cement, teknik för avlägsnande av överskottscement och kombinationen av de två faktorerna.Metod: 60 extraherade tänder preparerades i emalj med en slipmaskin till en 90° vinkel. Sintrat IPS E-max CAD preparerades till 60 bitar med måtten 3x3x1mm. Glaskerambitarna cementerades med Variolink®Veneer, Variolink®II och Panavia™F 2.0 enligt bruksanvisning med en kraft på 5kg. Varje cementgrupp bestod av 20 provkroppar där cementöverskottet avlägsnades med putsning eller konventionell teknik. Detta ledde till totalt 6 grupper med 10 provkroppar i varje grupp. Provkropparna termocyklades i 5000 cyklar i destillerat vatten med temperaturen 5° C till 55° C, därefter placerades provkropparna 4 dagar i kaffe och 4 dagar i rött vin. Missfärgningsgraden av det marginala cementet avlästes i en blindad studie under mikroskop av två observatörer med signifikant klinisk erfarenhet inom dentala keramer. Resultat: Variolink®Veneer var det minst missfärgande cementet oberoende av avlägsningsteknik, men resultatet var inte statistiskt signifikant. Putsning visade bättre motstånd gällande missfärgning jämfört med konventionell teknik och detta resultat var statistiskt signifikant. Variolink®II tillsammans med putstekniken var det minst missfärgande kombinationerna.Signifikans: Inom de begränsningar en in vitro studie medför kan följande slutsats dras; den viktigaste parametern gällande resistens av marginal missfärgning är ej val av cement utan tekniken för avlägsning av överskottscement. / Purpose: The aim of this study was to investigate the resistance to marginal discoloration of an adhesively cemented bondable ceramic to enamel depending on choice of cement, the technique used for removing excess cement and a combination of the two factors. Method: 60 extracted teeth were prepared in the enamel with a grinding machine to an approximately 90° angle. A block of IPS E-max CAD was sintered and thereafter sliced into 60 pieces with the measurement 3x3x1mm. The ceramic pieces were cemented with Variolink®Veneer, Variolink®II and Panavia™F 2.0 following the manufacturer’s instructions with a force of 5kg (20 specimens in each group). The excess cement was removed by either polishing technique or conventional technique leading to 6 groups with 10 specimens in each group. The specimens were thermocycled for 5000 cycles in 5° C and 55° C distilled water baths and after placed in coffee for 4 days and red wine for 4 days. The discoloration degree of the cement margin was analysed blindly under microscope by two observers with significant clinical experience in dental ceramics.Results: Variolink®Veneer was the least discolored cement but the result was not statistical significant. When comparing polishing and conventional technique, polishing showed least discoloration independent of choice of cement. Variolink®II together with the polishing technique showed least discoloring mean and median value of the 6 groups.Significance: Within the restrictions an in vitro study has, the following conclusion can be made; the most important parameter regarding resistance to marginal discoloration is not the choice of cement but how the excess cement is removed.

"October, 2005" / Coursework / Bibliography: leaves 97-105. / xvi, 136 leaves : / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (D.Clin.Dent.)--University of Adelaide, Dental School (Endodontics), 2005

<p>The objective of this study was to assess coronal discoloration due to four commonly used endodontic sealers with gutta-percha, using spectrophotometric analysis. Extracted human teeth were obturated with the experimental sealers and GP. The sealers that were tested included AH Plus, EndoRez, and Kerr Pulp Canal Sealer. The teeth were maintained in a moist environment at 37 C. Immediate pretreatment readings of the crowns of the extracted teeth with a spectrometer were used as baseline data. Subsequent readings were taken every two weeks for two months. Results were analysed using Wilcoxson Signed Rank sum test and Kruskal Wallis test.</p>