Effects of Light Activation, Agent Concentration, and Tooth Thickness on Dental Sensitivity After Bleaching

Examining three bleaching systems, this in vivo clinical trial evaluated the relationship among tooth sensitivity, light activation, and agent concentration, and it correlated dental sensitivity with tooth thickness.Materials and Methods: Eighty-seven volunteer patients were included. Inclusion criteria were the presence of anterior teeth without restorations as well as the absence of a previous bleaching experience and absence of non-carious cervical lesions or dental pain. Exclusion criteria included pregnancy or breastfeeding, a maximum of TF3 hypoplasia, tetracycline-fluorosis stains, malpositioned teeth, orthodontic treatment, periodontal disease, and/or analgesic/anti-inflammatory intake. Patients were randomly assigned to three bleaching groups: Group A (n=25) was treated with 15% H2O2 and nitrogenous-titanium-dioxide and was light activated (Lase Peroxide Lite, DMC, SaoCarlos, Sao Paulo, Brazil); Group B (n=27) was treated with 35% H2O2 and was light activated (Lase Peroxide Sensy, DMC); and Group C (n=35) was treated with 35% H2O2 (White Gold Office, Dentsply, 38West Clark Ave., Milford, USA) without light activation. Tooth sensitivity (TS) was self-reported by the patients using the visual analog scale (VAS) at baseline (TSO), immediately after treatment (TSI), and at seven days after treatment (TS7). In 46 patients, tooth thickness was determined by computed tomography. TSO, TSI, and TS7 were compared between the A and B groups to determine the effect of concentration and between the B and C groups to determine the effect of light using analysis of covariance. The correlation between tooth thickness and TSI was determined by Spearman Rho test (SPSS 15).Results: Eighty-seven patients were evaluated at baseline, and 61 were evaluated at seven days. Separated by groups, tooth sensitivity, expressed as VAS value at the time points TS0, TS1, and TS7, respectively, were as follows: Group A: 13.76 +/- 13.53, 24.40 +/- 25.24, and 5.94 +/- 5.5; Group B: 15.07 +/- 18.14, 42.4 +/- 31.78, and 8.68 +/- 17.99; and Group C: 10.80 +/- 14.83, 31.51 +/- 29.34, and 7.24 +/- 9.2. Group A showed significantly lower tooth sensitivity than group B at TSI (p=0.032). No differences were observed in the tooth sensitivities between groups B and C. No correlation was encountered between tooth thickness and tooth sensitivity immediately after treatment (Rho=-0.088,p=0.563). The median tooth thickness was 2.78 +/- 0.21 mm.Conclusions: Increases in the concentration of bleaching agents directly affect tooth sensitivity, and LED/laser activation and tooth thickness are not correlated with tooth sensitivity after dental bleaching.

Empirical models for estimating the suspended sediment concentration in Amazonian white water rivers using Landsat 5/TM

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Increased carbon dioxide concentration in the air reduces the severity of Ceratocystis wilt in Eucalyptus clonal plantlets

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Intraocular pressure, specular microscopy, and prostaglandin E-2 concentration in dogs with mature and hypermature cataract

This study aimed to evaluate and correlate intraocular pressure (IOP), endothelial cell density (CD), and hexagonality (HEX), and the aqueous humor prostaglandin E-2 (PGE(2)) concentration in dogs with mature (MG, n = 8) and hypermature (HG, n = 8) cataracts. Eight laboratory beagles with no ocular abnormalities were included as a control group (CG). The IOP was measured using a digital applanation tonometer. Noncontact specular microscopy was used to evaluate CD and HEX. Samples of aqueous humor were used to determine prostaglandin E-2 concentration using enzyme-linked immunoassay. Data were compared by ANOVA and Bonferroni's multiple comparison test, and possible correlations among the PGE(2) aqueous concentration and corneal endothelium cell parameters were assessed by Person's test (P < 0.05). Average values of IOP (P = 0.45) and CD (P = 0.39) were not significantly different between MG, HM, and CG. Average values of HEX were lower, and PGE(2) concentration was increased in the MG and HG in comparison with CG (P < 0.05); however, such parameters did not change significantly between MG and HG (P > 0.05). PGE(2) values did not correlate with IOP, CD, and HEX in any group (P > 0.05). Although there were a small number of dogs studied, our results demonstrated that cataract progression from mature to hypermature did not have a significant change in PGE(2) aqueous concentration, IOP, corneal endothelial cell count, or morphology. In addition, PGE(2) concentration was not correlated with parameters of the corneal endothelium or IOP in dogs with mature or hypermature cataracts.

Serum thiamine concentration and oxidative stress as predictors of mortality in patients with septic shock

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Pentraxin-3 concentration in the amniotic fluid of women at term, in spontaneous preterm labor and when not in labor

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Low Concentration H2O2/TiO_N in Office Bleaching: A Randomized Clinical Trial

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Influence of Concentration and Activation on Hydrogen Peroxide Diffusion through Dental Tissues In Vitro

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Type 2 Diabetes Elicits Lower Nitric Oxide, Bradykinin Concentration and Kallikrein Activity Together with Higher DesArg(9)-BK and Reduced Post-Exercise Hypotension Compared to Non-Diabetic Condition

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Silicone insulators of power transmission lines with a variable inorganic load concentration: Electrical and physiochemical analyses

Polymeric insulation is an increasing tendency in projects and maintenance of electrical networks for power distribution and transmission. Electrical power devices (e. g., insulators and surge arresters) developed by using polymeric insulation presents many advantages compared to the prior power components using ceramic insulation, such as: a better performance under high pollution environment; high hydrophobicity; high resistance to mechanical, electrical and chemical stresses. The practice with silicone insulators in polluted environments has shown that the ideal performance is directly related to insulator design and polymer formulation. One of the most common misunderstandings in the design of silicone compounds for insulators is the amount of inorganic load used in their formulation. This paper attempts to clarify how the variation of the inorganic load amount affects physicochemical characteristics of different silicone compounds. The physicochemical evaluation is performed from several measurements, such as: density, hardness, elongation, tensile strength. In addition, the evaluation of the physicochemical structure is carried out using infrared test and scanning electronic microscopy (SEM). The electrical analysis is performed from the electric tracking wheel and erosion test, in agreement with the recommendation of the International Electrotechnical Commission (IEC). (C) 2014 Elsevier Ltd. All rights reserved.

Estimating the concentration of gold nanoparticles incorporated on natural rubber membranes using multi-level starlet optimal segmentation

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)