Effects of different bleaching application time on tooth color and mineral alteration

Clinical Relevance The use of laser light during bleaching will not reduce the incidence or severity of sensitivity and will not increase the degree of color change compared with nonlaser light sources. SUMMARY Objective: To evaluate whether the use of laser during in-office bleaching promotes a reduction in dental sensitivity after bleaching compared with other light sources. Methods: The present review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) and is registered with PROSPERO (CDR42018096591). Searches were conducted in the PubMed/Medline, Web of Science, and Cochrane Library databases for relevant articles published up to August 2018. Only randomized clinical trials among adults that compared the use of laser during in-office whitening and other light sources were considered eligible. Results: After analysis of the texts retrieved during the database search, six articles met the eligibility criteria and were selected for the present review. For the outcome dental sensitivity, no significant difference was found favoring any type of light either for intensity (mean difference [MD]: −1.60; confidence interval [CI]: −3.42 to 0.22; p=0.09) or incidence (MD: 1.00; CI: 0.755 to 1.33; p=1.00). Regarding change in tooth color, no significant differences were found between the use of the laser and other light sources (MD: −2.22; CI: −6.36 to 1.93; p=0.29). Conclusions: Within the limitations of the present study, laser exerts no influence on tooth sensitivity compared with other light sources when used during in-office bleaching. The included studies demonstrated that laser use during in-office bleaching may have no influence on tooth color change.

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The Whitening Effect and Histological Safety of Nonthermal Atmospheric Plasma Inducing Tooth Bleaching

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18094714 ◽

2021 ◽

Vol 18 (9) ◽

pp. 4714

Author(s):

Seoul-Hee Nam ◽

Byul Bo Ra Choi ◽

Gyoo-Cheon Kim

Keyword(s):

Alternative Energy ◽

Soft Tissues ◽

Inflammatory Responses ◽

Color Change ◽

Atmospheric Pressure Plasma ◽

Atmospheric Plasma ◽

Tooth Bleaching ◽

Histological Evaluation ◽

Light Sources ◽

Tooth Color

Various light sources have been applied to enhance the bleaching effect. This study was to identify the histological evaluation in oral soft tissues, as well as tooth color change after tooth bleaching by nonthermal atmospheric pressure plasma (NAPP). Nine New Zealand adult female rabbits were randomly divided into three groups (n = 3): group 1 received no treatment; group 2 was treated with NAPP and 15% carbamide peroxide (CP), which contains 5.4% H2O2, and group 3 was treated with 15% CP without NAPP. Color change (ΔE) was measured using the Shade Eye NCC colorimeter. Animals were euthanized one day later to analyze the histological responses occurring in oral soft tissues, including pulp, gingiva, tongue, buccal mucosa, and hard and soft palates. Changes in all samples were analyzed by hematoxylin and eosin staining and Masson’s trichrome. Teeth treated with plasma showed higher ΔE than that obtained with bleaching agents alone. Overall, the histological characteristics observed no appreciable changes. The combinational treatment of plasma had not indicated inflammatory responses as well as thermal damages. NAPP did not cause histological damage in oral soft tissues during tooth bleaching. We suggest that NAPP could be a novel alternative energy source to conventional light sources for tooth bleaching.

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Tooth discoloration induced by apical plugs with hydraulic calcium silicate-based cements in teeth with open apices—a 2-year in vitro study

Clinical Oral Investigations ◽

10.1007/s00784-021-04009-0 ◽

2021 ◽

Author(s):

Ralf Krug ◽

C. Ortmann ◽

S. Reich ◽

B. Hahn ◽

G. Krastl ◽

...

Keyword(s):

Calcium Silicate ◽

In Vitro Study ◽

Color Difference ◽

Blood Contamination ◽

Tooth Color ◽

Color Changes ◽

Gutta Percha ◽

Tooth Discoloration ◽

Post Hoc

Abstract Objectives To assess tooth discoloration induced by different hydraulic calcium silicate-based cements (HCSCs), including effects of blood and placement method. Materials and methods Eighty bovine teeth cut to a length of 18 mm (crown 8 mm, root 10 mm) were randomly assigned to 10 groups (n = 8), receiving orthograde apical plug treatment (APT). Apical plugs were 4 mm in length and made of ProRoot MTA (Dentsply), Medcem MTA (Medcem), TotalFill BC RRM Fast Set Putty (Brasseler), or Medcem Medical Portland Cement (Medcem) plus bismuth oxide (Bi2O3) with and without bovine blood. Further, orthograde (with or without preoperative adhesive coronal dentin sealing) and retrograde APT were compared. Teeth were obturated with gutta-percha and sealer, sealed with composite and stored in distilled water. Tooth color was measured on apical plug, gutta-percha/sealer, and crown surface before treatment versus 24 h, 1, 3, 6, 12, and 24 months after treatment by spectrophotometry. Color difference (ΔE) values were calculated and analyzed by Shapiro–Wilk test, ANOVA with post hoc tests, Friedman test, t test, and post hoc tests with Bonferroni correction (α = .05). Results Tooth discoloration occurred in all groups with no significant differences between HCSCs (p > .05). After 24 months, color changes were prominent on roots but insignificant on crowns. Blood contamination induced a significantly decreased luminescence (p < .05). Blood had a stronger impact on tooth color than Bi2O3. No relevant effects of retrograde placement (p > .05) or preoperative dentin sealing (p > .05) were detected. Conclusions Apical plugs of the tested HCSCs cause discoloration of bovine roots, but not discoloration of bovine tooth crowns within a 24-month period. Clinical relevance APT should be performed carefully while avoiding direct contact with the coronal dentin, and in that case no aesthetic impairments occur.

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TCTAP A-032 Proper Application Time and Effect of Extracorporeal Membrane Oxygenation in the Patients Who Underwent Percutaneous Coronary Intervention for Acute Myocardial Infarction with Cardiogenic Shock

Journal of the American College of Cardiology ◽

10.1016/j.jacc.2021.03.059 ◽

2021 ◽

Vol 77 (14) ◽

pp. S19-S20

Author(s):

Dae Young Hyun ◽

Myung-Ho Jeong ◽

Min Chul Kim ◽

Kyung Hoon Cho ◽

Doo Sun Sim ◽

...

Keyword(s):

Myocardial Infarction ◽

Acute Myocardial Infarction ◽

Percutaneous Coronary Intervention ◽

Extracorporeal Membrane Oxygenation ◽

Cardiogenic Shock ◽

Coronary Intervention ◽

Application Time ◽

Membrane Oxygenation ◽

Percutaneous Coronary

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Preparation and Performance Evaluation of Duotone 3D-Printed Polyetheretherketone as Oral Prosthetic Materials: A Proof-of-Concept Study

Polymers ◽

10.3390/polym13121949 ◽

2021 ◽

Vol 13 (12) ◽

pp. 1949

Author(s):

Ling Ding ◽

Wei Lu ◽

Jiaqi Zhang ◽

Chuncheng Yang ◽

Guofeng Wu

Keyword(s):

Titanium Dioxide ◽

Performance Evaluation ◽

Mechanical Performance ◽

Mechanical Tests ◽

Flexural Properties ◽

Proof Of Concept ◽

Tooth Color ◽

Dental Application ◽

3D Printed ◽

And Performance

Literature has reported the successful use of 3D printed polyetheretherketone (PEEK) to fabricate human body implants and oral prostheses. However, the current 3D printed PEEK (brown color) cannot mimic the vivid color of oral tissues and thus cannot meet the esthetical need for dental application. Therefore, titanium dioxide (TiO2) and ferric oxide (Fe2O3) were incorporated into PEEK to prepare a series of tooth-color and gingival-color PEEK composites in this study. Through color measurements and mechanical tests, the color value and mechanical performance of the 3D printed PEEK composites were evaluated. In addition, duotone PEEK specimens were printed by a double nozzle with an interface between tooth-color and gingival-color parts. The mechanical performance of duotone PEEK with two different interfaces (horizontal and vertical) was investigated. With the addition of TiO2 and Fe2O3, the colors of 3D printed PEEK composites become closer to that of dental shade guides. 3D printed PEEK composites generally demonstrated superior tensile and flexural properties and hence have great potential in the dental application. In addition, duotone 3D printed PEEK with a horizontal interfacial orientation presented better mechanical performance than that with a vertical one.

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Yield, germination and herbicide residue in seeds of preharvest desiccated wheat

Journal of Seed Science ◽

10.1590/2317-1545v40n3191284 ◽

2018 ◽

Vol 40 (3) ◽

pp. 304-312 ◽

Cited By ~ 3

Author(s):

Lais Tessari Perboni ◽

Dirceu Agostinetto ◽

Leandro Vargas ◽

Joanei Cechin ◽

Renan Ricardo Zandoná ◽

...

Keyword(s):

Wheat Yield ◽

Application Rate ◽

Application Time ◽

Herbicide Application ◽

Herbicide Residue ◽

Application Rates ◽

Weight Yield ◽

Time Periods ◽

Dough Stage ◽

Wheat Seeds

Abstract: The goals of this study were to evaluate herbicide application rates at different timings for preharvest desiccation of wheat (Trial 1), as well as to evaluate the effect of the timing of herbicide desiccation at preharvest and harvest timing (Trial 2) on yield, germination, and herbicide residue in wheat seed. In Trial 1, treatments consisted of two application rates of glufosinate, glyphosate, paraquat, or paraquat+diuron and a control without application; application time periods were in the milk grain to early dough stage, soft dough to hard dough stage, and hard dough stage. In Trial 2, treatments consisted of different application time periods (milk grain to early dough stage, and soft dough to hard dough stage), different herbicides (glufosinate, 2,4-D+glyphosate, and untreated control), and different harvest times (5, 10 and 15 days after herbicide application). One thousand seeds weight, yield, first and final germination count, and herbicide residue on seeds were evaluated. Preharvest desiccation with paraquat, glufosinate, and 2,4-D+glyphosate at the milk grain to early dough stage reduces wheat yield. Regardless of the herbicide and application rate, application in the milk grain to early dough stage and soft dough to hard dough stage provides greater germination of wheat seeds, except at the lower dose of paraquat. Systemic herbicides accumulate more in wheat seeds.

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