Minimal Discoloration Research Articles

An in Vitro Study of the Effects of Different Dentin Bonding Agents on the Prevention of Tooth Discoloration and the Sealing Ability of Calcium Silicate-Based Cement in Regenerative Endodontic Procedures

This study aimed to compare the effects of applying different types of dentin bonding agents (DBAs) on tooth and on the sealing ability of CSC in regenerative endodontic procedures (REPs). Specimens were made from 120 human first premolars and categorized into the following groups based on the presence and the type of DBA: Group I, no bonding; Group II, One-Step; Group III, Clearfil SE Bond; and Group IV, Single Bond Universal. Subsequently, the groups were categorized into Subgroup a and Subgroup b, in which Endocem MTA® Premixed Regular and Biodentine were used, respectively. The CIE L*a*b* on the photos taken prior to TAP placement (S0), 1 week after TAP placement (S1), 2 weeks after TAP placement (S2), 4 weeks after TAP placement (S3) and 2 weeks after CSC placement (S4) was used to assess discoloration. The samples were submerged in a 2% methylene blue solution and magnified by 30 times under a stereomicroscope to assess microleakage. The application of DBA during REP reduced crown discoloration, while Biodentine showed minimal discoloration with or without DBA and regardless of the DBA type. Additionally, the application of DBA did not increase microleakage.

An Unusual Case of Tongue Entrapment in a Plastic Water Bottle

Background: Foreign bodies inside the oral cavity are commonly encountered among children. One peculiar occurrence is when the tongue gets entrapped in foreign bodies such as bottles. This happens as children often insert their tongues into the bottle and apply oral suction to ingest the last few drops from the bottle. There is a paucity of data in Indian literature and no recommended guidelines for the management of such cases. Clinical Description: The patient, a 12-year-old boy had a history of inability to remove a plastic water bottle sipper from around the tongue while swallowing water quickly. He was initially asymptomatic and then he started developing progressive pain and swelling on the anterior part of the tongue. On examination, the plastic sipper was constricting the tongue circumferentially and the patient felt a sharp pain on maneuvering the bottle. Minimal discoloration of the anterior part of the tongue had set in 1 h after the presentation. Management: Lubrication with 2% lignocaine jelly and ice packs circumferentially followed by attempts of gentle traction and manipulation to remove the foreign body were unsuccessful. Consequently, the patient was shifted to the emergency operation theater where the patient was sedated with intravenous (IV) ketamine and midazolam after securing a nasopharyngeal airway with 100% preoxygenation. An orthopedic bone cutter was used, and a radial cut was given on the impacted end of the bottle, and the constricted part was removed as pressure on the tongue was released, followed by 100% oxygenation with bag and mask ventilation. Conclusion: Immediate intervention in cases of the entrapped tongue can prevent grave consequences such as airway compromise and tongue ischemia and necrosis. Mechanical removal can be done safely using heavy scissors or orthopedic bone under IV sedation after securing the airway in collaboration with the anesthesia team.

Analysis of chemical deposits on tooth enamel exposed to total particulate matter from cigarette smoke and tobacco heating system 2.2 aerosol by novel GC–MS deconvolution procedures

Tobacco smoking contributes to tooth discoloration. Pigmented compounds in the smoke generated by combustion of tobacco can cause discoloration of dental hard tissues. However, aerosols from heated tobacco products cause less discoloration than cigarette smoke (CS) in vitro. The objective of the present study was to optimize a method for extracting the colored chemical compounds deposited on tooth enamel following exposure to total particulate matter (TPM) from CS or a heated tobacco product (Tobacco Heating System [THS] 2.2), analyze the extracts by gas chromatography coupled to time-of-flight mass spectrometry, and identify the key chemicals associated with tooth discoloration. Sixty bovine enamel blocks were exposed for 2 weeks to TPM from CS or THS 2.2 aerosol or to artificial saliva as a control. Brushing without toothpaste and color measurements were performed each week. Noticeable discoloration of enamel was observed following exposure to CS TPM. The discoloration following exposure to THS 2.2 aerosol TPM or artificial saliva was not distinguishable to the eye (ΔE < 3.3). Carbon disulfide was used to extract surface-deposited chemicals. Untargeted analyses were followed by partial least squares correlation against discoloration scores (R2 = 0.96). Eleven compounds had variable importance in projection scores greater than 2. Discriminant autocorrelation matrix calculation of their mass spectral information identified eight of the eleven compounds as terpenoids. None of the compounds were related to nicotine. Several of these compounds were also detected in THS 2.2 aerosol TPM-exposed enamel, but at lower levels, in line with our findings showing less discoloration. Compared with CS TPM exposure, THS 2.2 aerosol TPM exposure resulted in lower deposition of color-related compounds on enamel surface, consistent with minimal discoloration of dental enamel.

MON-LB67 Bisphosphonate Related Ocular Inflammation

MON-LB67 Bisphosphonate Related Ocular Inflammation

Obtaining optimal esthetics with veneered zirconia and lithium disilicate frameworks on substrates of different colors

This study sought to describe the clinical and laboratory procedures and to discuss aspects involved in obtaining satisfactory esthetics on substrates presenting different colors. This case report describes the clinical and laboratory procedures for obtaining an optimal esthetic result using different ceramic framework materials veneered with feldspathic ceramic over substrates of different colors. Zirconia frameworks were used for darkened substrates and were reinforced with lithium disilicate for substrates with minimal discoloration. The same feldspathic veneering ceramic was applied to provide similar translucency and color for favorable esthetics. The materials explored in the present case report presented favorable aesthetic results in masking darkened substrates. Clinicians should consider the condition and color of the substrate when selecting the restorative material for masking such a condition.

Triple antibiotic paste––Challenging intracanal medicament: A systematic review

Aim: To evaluate and compare the performance of triple antibiotic paste (TAP) as intracanal medicaments during the root canal treatment. Materials and Methods: Search strategy included the in vivo studies, in vitro studies, and clinical trials from the databases of PubMed Central, Cochrane, EBSCO, and MEDLINE from January 1981 to August 2019. A total of 223 articles were searched, of which 39 articles were relevant to our study. The searched articles were clinical trials, case reports, and original studies that met with inclusion criteria. Of which, 13 articles were used for quantitative synthesis. A systematic review was performed for TAPs, antibacterial efficiency, effect on mechanical properties, discoloration effect, and cytotoxicity on stem cells. Results: In the included studies, the systematic review articles, the evidence of antibacterial efficiency of TAP is significantly more efficient compared to other medicaments techniques. The mechanical properties has been evaluated, there is a mild reduction in the mechanical properties of the dentin. TAP plays a significant role in reducing the chronic periapical infections. It shows minimal discoloration effect and minimal cytotoxicity to dental pulp stem cell (DPSC) as compared to calcium hydroxide and Ledermix. Conclusion: This systematic review of available data and evidences reveals that TAP is significantly more efficient than the other intracanal medicaments because of its minimal discoloration effect on teeth and less toxic nature to the DPSCs.

Microneedling of Immature Scars Is Safe and Improves Scar Esthetics

PURPOSE: 1. Dispelling previous myths that immature scars could not be treated with microneedling. 2. Microneedling scars as early as 6 weeks following wound closure is safe. 3. Microneedling improves scars esthetics. Scar formation involves the remodeling of extracellular matrix proteins. Wound contraction and hyperproliferation can result in hypertrophic or keloid scars with features linked to poor cosmetic results. Currently early intervention with microneedling in immature scars is not the standard of care and some recommend waiting upward of 1 year before microneedling treatment. Our hypothesis is that mechanical stimulation of the myofibroblasts at the early tissue formation stage can positively influence the extracellular matrix to influence cell activity to produce collagen, matrix metalloproteinases, and cytokines which lead to flat scars with minimal discoloration as a result of small parallel collagen bundles METHODS AND MATERIALS: Subjects were enrolled between 6 weeks and 4 months following closure of their wounds. Once enrolled, the patients were treated with 3 microneedling treatments 1 month apart and a final evaluation at 2 months following the last treatment. The treatment areas included facelift, breast mastopexy, and tummy tuck scars. The patients consented to participate in the Institutional Review Board–approved study. Twenty-five patients were enrolled, and data were analyzed using analysis of variance and post hoc testing. RESULTS: The Vancouver Scar Scale demonstrated a statistically significant improvement when compared from the initial evaluation to the final evaluation at the 2-month follow-up following the 3 treatments (7.00 versus 3.08; P < 0.001). The Patient and Observer Scar Assessment Scale showed statistically significant improvement when initial evaluation was compared to the 2-month follow-up (23.72 versus 11.76; P < 0.001). CONCLUSIONS: Early microneedling on immature scars is safe and has demonstrated improvement in both Vancouver Scar Scale and Patient and Observer Scar Assessment Scale scores when initial evaluation is compared to 2-month follow-up.

Antibacterial Efficacy and Discoloration Potential of Endodontic Topical Antibiotics

IntroductionThe optimal concentration for the use of endodontic topical antibiotics is not known. The aims of this study were to determine the minimum bactericidal concentrations (MBCs) and minimum inhibitory concentrations (MICs) of metronidazole, ciprofloxacin, minocycline, Augmentin (GlaxoSmithKline, Research Triangle Park, NC), and tigecycline against common endodontic pathogens and to evaluate ex vivo the antibacterial efficacy and discoloration effect of triple antibiotic paste (TAP), Augmentin, and tigecycline at different concentrations using a slow-release hydrogel scaffold. MethodsUsing the Epsilometer test method (Etest; bioMérieux USA, St Louis, MO), MICs and MBCs of selected antibiotics were determined against Fusobacterium nucleatum, Porphyromonas gingivalis, Streptococcus intermedius, and Enterococcus faecalis. Biofilms of these bacterial species were then grown in extracted single-rooted teeth anaerobically for 3 weeks. Root canals were filled with TAP, Augmentin, and tigecycline at concentrations of 1 or 0.1 mg/mL in a degradable hydrogel scaffold or pure TAP at 1 g/mL for 7 days. Coronal discoloration was evaluated spectrophotometrically at 1, 2, and 3 weeks after dressing. ResultsMIC/MBC data showed significant efficacy of tigecycline, Augmentin, and minocycline compared with the other antibiotics (P < .05). Significant differences were found when comparing the log10 colony-forming units of all experimental groups (P < .05). TAP at 1 g/mL had no bacterial growth but caused the greatest discoloration. Hydrogel mixtures with TAP, Augmentin, or tigecycline at 1 mg/mL significantly reduced bacterial growth and the number of positive samples compared with those at 0.1 mg/mL (P < .05) with minimal discoloration. ConclusionsTAP, Augmentin, and tigecycline in a hydrogel at 1 mg/mL reduced bacterial growth significantly with minimal color change.

Tu1035 Lower Dose of Fluorescein Sodium Is More Suitable for Confocal Laser Endomicroscopy: A Feasible Study

Image quality can be guaranteed with the conventional dosage of fluorescein sodium in probe-based confocal laser endomicroscopy (pCLE). However, yellow discoloration of the skin seriously influences daily life and simultaneously increases the risk of adverse events such as allergy. This study is to test whether a lower dose of fluorescein sodium, which has minimal discoloration of skin, can provide satisfied image quality by a randomized blinded controlled trial.

Serrated Polyposis Syndrome: An Unusual Presentation Discovered After an Episode of Ischemic Colitis

Introduction: Serrated polyposis syndrome is a disease characterized by numerous, large, proximal sessile polyps. The polyps are often flat and tend to develop within the haustral folds with adherent mucus, which makes them difficult to detect on colonoscopic evaluation. Case Presentation: A 64-year old female with a past medical history of Hypertension, Coronary Artery Disease, and no previous colorectal neoplasia screening presented with the acute onset of diffuse abdominal pain and hematochezia. There was no recent travel history or antibiotic use. CT scan of the abdomen revealed circumferential thickening of the colon from the splenic flexure to the rectum with associated soft tissue stranding. Flexible Sigmoidoscopy performed upon admission showed severe inflammation of the sigmoid colon consistent with ischemic colitis. The patient was treated supportively with improvement in her presenting symptoms. Several weeks after her hospitalization, she underwent a full colonoscopy, which revealed multiple sessile polyps proximal to the sigmoid colon. The majority of the polyps were located in the ascending colon, the largest of which measured approximately 20 mm. Most, but not all, were resected, and pathology was consistent with sessile serrated polyps. Several more sessile polyps were removed from the proximal colon during a follow-up exam performed three months later. Pathology was again consistent with sessile serrated adenomas. Discussion: Serrated Polyposis Syndrome remains both a diagnostic and therapeutic dilemma. It is relatively uncommon disease, representing approximately 1 case for every 2000 screening colonoscopies performed. Sessile serrated polyps are believed to be more aggressive than common tubular adenomas, therefore a high index of suspicion is required. However, the characteristics of sessile serrated polyps (flat with minimal discoloration) make detection difficult on routine colonoscopic evaluation. The flat nature of these polyps also makes for an increased risk of incomplete resection and possibly even colonic perforation. Surveillance intervals have also not been concretely defined, but current recommendations suggest repeat colonoscopy every one to two years as some studies suggest an increased future risk of colorectal cancer.Figure 1Figure 2

Femtosecond laser cleaning of historical paper with sizing

Lasers have served as cleaning tools for historical objects and artworks for about 40 years. In many cases, superior results of laser cleaning were achieved with respect to traditional methods. In this technique, contaminations on the surface of the object are ablated by laser irradiation. In order to apply laser cleaning method to fragile materials such as paper made of cellulose or parchment, heat deposition to the bulk should be minimal, to prevent damage. In this work, it is demonstrated that laser pulses with femtosecond (fs) duration can exhibit non-thermal ablation of contaminants on paper samples. In particular, laser cleaning studies are concentrated on paper samples with sizing. Fs laser cleaning is performed on artificially soiled and aged samples, as well as on historical ones. The laser used in the experiments has pulse duration of 550 fs and 1030 nm center wavelength. The fluence of the laser is varied and the post-cleaning statuses of samples are investigated. The analyses are color changes, fiber integrity, chemical composition changes and mechanical strengths. These results show that fs lasers can be very efficient in cleaning paper samples, yielding minimal discoloration and no damage to fibers distinguishable on microscopic examination. The presence of sizing also provides further protection against possible side effects.

A disposable system for rapid purification of autologous plasmin as an adjunct to vitrectomy — performance and safety profile

The generation of an atraumatic posterior vitreous detachment (PVD), a common goal in vitreoretinal surgery, is a challenge particularly in children and young trauma patients. Plasmin has been proposed as a surgical adjunct to enzymatically generate a PVD. This study assesses the performance and safety of a new system for rapid purification of plasmin as an adjunct to vitrectomy. Plasminogen was isolated from human plasma by affinity chromatography using a disposable rapid purification kit, and activated to plasmin with streptokinase. Activities were assessed spectrophotometrically. For safety studies, 38 rabbits received intravitreal injections of one of the following compounds in 0.1 ml respectively: 4.7, 12.7 and 24 IU plasmin, 15 mg dextran, 4,100 U streptokinase, 500 μg ε-aminocaproic acid, 0.1 M potassium phosphate or balanced salt solution (BSS). Thirty min after injection, a two-port vitrectomy was performed. Rabbits were followed clinically and with bright flash electroretinography (ERG) for up to 9 months. The eyes were investigated by light and transmission electron microscopy. The specific plasmin activity obtained from blood of healthy volunteers averaged 42.3 ± 6.6 IU/ml (range 21.6 IU/ml to 54.5 IU/ml). The identity and purity of the enzyme was confirmed by several methods. Clinically, a mild to moderate inflammatory response was seen in most eyes on day 1, but had disappeared by day 7. ERG showed moderate depressions of a- and b-wave amplitudes on day 2, particularly in the potassium phosphate (a: -29.16 ± 4.56, b: -21.23 ± 6.31), 4.7 (a: -34.38 ± 6.64, b: -26.66 ± 6.06) and 24 IU (a: -38.25 ± 4.05, b: -23.38 ± 4.29) plasmin groups, but also in the BSS- (a: -11.19 ± 21.78, b: -11.41 ± 15.47) and dextran- (a: -17.86 ± 14.18, b: -6.67 ± 18.14) treated eyes. ERG changes recovered during follow-up. One rabbit each from the 12.7 and the 24 IU plasmin groups showed a minimal discoloration of one medullary ray after 9 months. Histology did not reveal morphologic signs of toxicity. The isolation system generated plasmin with a high degree of purity. A failure-mode analysis did not reveal significant risks of toxicity. A single preparation can provide a maximum dose of 10.9 IU/200 μl, the likely target clinical dose being 1.88 IU. Plasmin doses of at least 12.7 IU appear be safe when injected into rabbit eyes, followed by vitrectomy.

Reattachment of crown fragment for immediate esthetics

Tobacco smoking contributes to tooth discoloration. Pigmented compounds in the smoke generated by combustion of tobacco can cause discoloration of dental hard tissues. However, aerosols from heated tobacco products cause less discoloration than cigarette smoke (CS) in vitro. The objective of the present study was to optimize a method for extracting the colored chemical compounds deposited on tooth enamel following exposure to total particulate matter (TPM) from CS or a heated tobacco product (Tobacco Heating System [THS] 2.2), analyze the extracts by gas chromatography coupled to time-of-flight mass spectrometry, and identify the key chemicals associated with tooth discoloration. Sixty bovine enamel blocks were exposed for 2 weeks to TPM from CS or THS 2.2 aerosol or to artificial saliva as a control. Brushing without toothpaste and color measurements were performed each week. Noticeable discoloration of enamel was observed following exposure to CS TPM. The discoloration following exposure to THS 2.2 aerosol TPM or artificial saliva was not distinguishable to the eye (ΔE < 3.3). Carbon disulfide was used to extract surface-deposited chemicals. Untargeted analyses were followed by partial least squares correlation against discoloration scores (R2 = 0.96). Eleven compounds had variable importance in projection scores greater than 2. Discriminant autocorrelation matrix calculation of their mass spectral information identified eight of the eleven compounds as terpenoids. None of the compounds were related to nicotine. Several of these compounds were also detected in THS 2.2 aerosol TPM-exposed enamel, but at lower levels, in line with our findings showing less discoloration. Compared with CS TPM exposure, THS 2.2 aerosol TPM exposure resulted in lower deposition of color-related compounds on enamel surface, consistent with minimal discoloration of dental enamel.

Effects of polyvinyl chloride overwrap film, high-oxygen modified atmosphere packaging, or ultra-low-oxygen modified atmosphere packaging on bone marrow discoloration in beef humerus, rib, thoracic vertebra, and scapula1

Meat retailers have reported bone marrow discoloration to be a problem, especially in modified atmosphere packages (MAP). Therefore, it is important to determine the prevalence and cause(s) of bone marrow discoloration in different beef bones and packaging systems. Thirty-six beef humeri, ribs, scapulas, and thoracic vertebrae from USDA Select and Choice carcasses were obtained from a commercial abattoir, cut into 2.54-cm-thick sections at 4 d postmortem, and packaged into 1 of 3 systems: 1) polyvinyl chloride film (PVC) overwrap; 2) high-oxygen (80% O2, 20% CO2) MAP; and 3) ultra-low-oxygen (70% N2, 30% CO2) MAP. Instrumental reflectance and visual color scores were taken on d 0, 2, and 4, and on d 0 to 4 of display, respectively. Bone marrow was extracted from humeri, ribs, and thoracic vertebrae for analysis but not from scapulas. Ribs, scapulas, and thoracic vertebrae packaged in PVC and high-oxygen MAP developed undesirable gray or black discoloration. In ultra-low-oxygen MAP, mean visual color scores were acceptable throughout the entire display period. Discoloration (darkening) was more extensive for ribs, scapulas, and thoracic vertebrae than for humeri, especially for bones packaged in PVC and high-oxygen MAP. Humeri had lower (P < 0.05) a* values (larger positive a* values indicate a redder color) than the other bones. The a* values for ribs, scapulas, and thoracic vertebrae decreased (P < 0.05) over time. Chroma showed that bone marrow discolored during display, but graying was dramatically less for all bones packaged in ultra-low-oxygen MAP and for humeri in PVC and high-oxygen MAP. Humeri marrow had lower (P < 0.05) 2-thiobarbituric acid reactive substances (TBARS) than did ribs and thoracic vertebrae marrow. Ultra-low-oxygen MAP resulted in the least amount of change in TBARS from d 0 to 4, whereas thoracic vertebrae marrow had greater (P < 0.05) TBARS values at d 4 of display than at d 0 in PVC and high-oxygen MAP. Humeri marrow had dramatically less total Fe and hemoglobin than did that of ribs and thoracic vertebrae for all packaging systems. Myoglobin was undetectable in humeri marrow. The much larger amounts of Fe and hemoglobin in ribs and thoracic vertebrae likely contribute to marrow discoloration. Bone marrow discoloration was distinct in ribs, scapulas, and thoracic vertebrae packaged in PVC or high-oxygen MAP. Bones packaged in ultra-low-oxygen MAP had minimal discoloration.

Photolytic discoloration of azo dye incorporated organoiron polymer

Organoiron polymers with azo dyes pendant to the backbone incurred loss of color upon irradiation with UV light ( λ = 300 nm) in acetonitrile solution. The loss of color is attributed to the interaction of the cleaved iron moiety with the azo chromophore. Similarly, addition of small amounts (⩽1 mM) of both Fe(II) and Fe(III) to the organic polymer analogue yielded comparable discoloration rates upon irradiation. The iron cation forms a complex with the azo chromophore group in the polymer, and subsequently leads to the photodegradation of the azo dye. At higher initial polymer concentrations, minimal discoloration was observed due to the light attenuation effect of the deeply colored solutions. In the presence of small amounts of water, the iron cation is inhibited from partaking in complex formation and no polymer discoloration was observed. For the organic polymer analogue, the presence of water did not show significant change over its absence upon irradiation. The discoloration of the polymer relies solely on its interaction with the iron cation present in solution, and does not require addition of any catalyst or reagent. This process might be developed into a pragmatic and viable method for the treatment of specifically designed colored materials using only UV light.

Comparison of Hepatic Damage from Direct Injections of Iodinated Contrast Agents and Carbon Dioxide

This study guides the choice of contrast agent for localization of portal veins during transjugular intrahepatic portosystemic shunt (TIPS) placement or use in percutaneous transhepatic cholangiography (PTC) by providing gross anatomic and histologic comparison of effects from parenchymal injections of iodinated contrast agents and carbon dioxide. Eighteen New Zealand White rabbits received direct injections of 2-5 mL of either the nonionic contrast agent iohexol 300 mgI or the ionic contrast agent diatrizoate meglumine 60% into one lobe of the liver and the same volume of CO2 into the other lobe. The rabbits were killed at 2-7 days for gross and histologic evaluation of the livers. At the time of injection, the diatrizoate and iohexol sites showed persistent dark discoloration, whereas CO2 sites showed minimal visible changes. On gross examination at death, all diatrizoate sites showed severe scarring and also commonly showed areas of necrosis. CO2 and iohexol sites showed only minimal discoloration and needle-puncture scars (P < .0001). The histologic grade for diatrizoate sites was significantly more severe than paired CO2 sites (P < .016). Iohexol sites showed mild histologic changes similar to paired CO2 sites (P = .375). Iohexol and CO2 produce less severe hepatic damage and are preferred to meglumine diatrizoate for hepatic injection.

Outbreak of Black Root Rot in Catharanthus roseus Caused by Thielaviopsis basicola.

A bedding plant grower in southwest Florida reported severe losses in potted Catharanthus roseus (Madagascar periwinkle) transplanted on various dates in December 1997. Symptoms included yellowing of lower leaves, defoliation, black root rot, and plant death. Thielaviopsis basicola was consistently isolated from blackened roots on a selective medium (1). A disease survey was conducted during mid March 1998 of 7,500 periwinkle plants in the two cultivar series Pacific (cvs. Punch, Red, and White) and Cooler (cvs. Grape, Icy, Peppermint, Pink, and Raspberry). Black root rot symptoms were observed in 21 to 53% of periwinkles transplanted between 3 and 11 December, and in 0 to 19% of plants transplanted between 21 and 29 December. The two cultivar series did not appear to differ in their susceptibility to T. basicola. The fungus was consistently isolated from symptomatic periwinkle roots, from roots of chlorotic violas (Viola cornuta), and from a potting medium used for early December transplanting. Pathogenicity of isolates of T. basicola from periwinkle, viola, and the contaminated medium was investigated. Inocula were produced by growing the fungus on acidified potato dextrose agar for 18 days. Conidia, chlamydospores, and hyphae of T. basicola were suspended in deionized water (100 ml/95 mm culture plate). One milliliter of inoculum suspensions of each of the three isolates was used to inoculate 12 plants of pansy (Viola × Wittrockiana) cv. Majestic Giant Blue Shade. An equal number of plants served as noninoculated controls. In addition, 5 ml of each isolate suspension was used to inoculate three six-plant replications of periwinkle cv. Pink Cooler. Plants were incubated in a controlled environment chamber at day/night temperatures of 24/22°C with a 12-h photoperiod. After 22 days, moderate to severe root discoloration was produced in pansy by the viola isolate of the fungus, while periwinkle and potting medium isolates produced only minimal discoloration. Chlamydospores typical of T. basicola were observed in the roots of all inoculated pansies, and in the roots of one of 12 non-inoculated controls. After 38 days, periwinkle plants were rated for foliar yellowing (0 = no yellowing, to 3 = severe yellowing) and percent defoliation, and fresh weights of shoots and roots were obtained. T. basicola was recovered on the selective medium from roots of all inoculated plants and from 68% of the noninoculated controls, indicating that secondary spread had occurred. All three isolates of the fungus caused yellowing and defoliation, but only the periwinkle and potting medium isolates significantly reduced both shoot and root weights in periwinkle, compared with control plants. T. basicola has not been previously reported to cause black root rot in C. roseus, and a contaminated potting medium used during early December may have provided initial inocula for the outbreak. The unseasonably cool and rainy weather prevalent during winter 1997 and spring 1998 ("El Niño") may have also promoted the unusual appearance of the disease. Reference: (1) L. P. Specht and G. J. Griffin. Can. J. Plant Pathol. 7:438, 1985.

CHARACTERISTICS OF MINCED BEEF STORED AT CHILLED AND ABUSE TEMPERATURES

ABSTRACT Fresh minced beef samples were collected from retail food stores in the Eastern United States and stored for various periods at 4 and 25C. Evaluations included psychrotophic counts, microbial taxonomy, pH, total volatile nitrogen, malonaldehyde (TBARS), color and off odor. Minimal discoloration was observed through 5 days of storage at 4C; whereas, minced beef stored at 25C sustained major discoloration prior to storage for 12 h. After five days of storage at 4C, 11.6% of the samples exhibited an off odor compared to 29.8% after storage for 12 h at 25C. Psychrotrophic counts of less than 105/g were attained during storage at 4C for 5 days; whereas, samples stored at 25C exceeded this level after 12 h. Chemical indices suggested similar product deterioration. These observations suggested that fresh minced and aerobically packaged in a 4C environment will attain acceptable color without off odor development through 5 days of storage.

Growth Regulation of Bahiagrass (Paspalum notatum Fluegge) with Imazaquin and AC 263,222

Research was conducted over 2 years to evaluate efficacy of various levels and combinations of imazaquin and AC 263,222 for growth regulation of unimproved bahiagrass (`Pensacola') turf. Imazaquin at 0.42 kg·ha–1 caused only slight bahiagrass discoloration in all trials and reduced seedhead count (as compared to the nontreated control) by ≥80% for 8 weeks after treatment (WAT) following a July 1992 application. AC 263,222 at 0.042 or 0.056 kg·ha–1 applied in late May or June provided 100% seedhead control through 8 WAT. However, AC 263,222 applied in July 1992 and Aug. 1993 at 0.056 kg·ha–1 resulted in unacceptable discoloration through 8 WAT. AC 263,222 at 0.014 or 0.028 kg·ha–1 provided ≥90% seedhead control with only minimal discoloration following applications in July or Aug. 1993, indicating that lower rates of AC 263,222 provided acceptable seedhead control of bahiagrass during times when growth was slowed due to moisture stress. Chemical names used: (±)-2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl]-5-methyl-3-pyridinecarboxylic acid (AC 263,222); 2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl]-3-quinolinecarboxylic acid (imazaquin).

Temporary soft liners: A modified curing technique to extend liner longevity

A modified curing technique that will extend the useful clinic life of temporary soft liners has been described. This technique offers the following distinct advantages over the traditional method of intraoral curing: (1) a liner that is less porous; (2) a liner that maintains its resilience intraorally for extended periods; (3) a liner that exhibits minimal discoloration over time; (4) increased density that allows adjustments to be made when necessary; and (5) minimized separation from the acrylic resin denture base.