Shade Change Research Articles

Screen-Space Normal Distribution Function Caching for Consistent Multi-Resolution Rendering of Large Particle Data.

Molecular dynamics (MD) simulations are crucial to investigating important processes in physics and thermodynamics. The simulated atoms are usually visualized as hard spheres with Phong shading, where individual particles and their local density can be perceived well in close-up views. However, for large-scale simulations with 10 million particles or more, the visualization of large fields-of-view usually suffers from strong aliasing artifacts, because the mismatch between data size and output resolution leads to severe under-sampling of the geometry. Excessive super-sampling can alleviate this problem, but is prohibitively expensive. This paper presents a novel visualization method for large-scale particle data that addresses aliasing while enabling interactive high-quality rendering. We introduce the novel concept of screen-space normal distribution functions (S-NDFs) for particle data. S-NDFs represent the distribution of surface normals that map to a given pixel in screen space, which enables high-quality re-lighting without re-rendering particles. In order to facilitate interactive zooming, we cache S-NDFs in a screen-space mipmap (S-MIP). Together, these two concepts enable interactive, scale-consistent re-lighting and shading changes, as well as zooming, without having to re-sample the particle data. We show how our method facilitates the interactive exploration of real-world large-scale MD simulation data in different scenarios.

Shade Changes of Cemented CERASMART Laminate Veneers after Exposure to Commonly Consumed Beverages (An in Vitro Study)

Shade Changes of Cemented CERASMART Laminate Veneers after Exposure to Commonly Consumed Beverages (An in Vitro Study)

Comparative Evaluation of the Efficacy of In-Office Bleaching (37.5% Hydrogen Peroxide) and At-Home Bleaching (15% Carbamide Peroxide) Using Different Activation Systems.

INTRODUCTION: The majority of contemporary tooth whitening involves the use of either hydrogen peroxide or Carbamide peroxide as the bleaching agent. A recent increase in the treatment options of discoloured teeth has led to the development of various new techniques and materials. With recent development in bleaching techniques, many auxiliary apparatuses have been introduced for efficient bleaching. AIM: The purpose of the present study is to compare and evaluate the efficacy of In-office bleaching 37.5% hydrogen peroxide and At-home bleaching 15% Carbamide peroxide using different activation systems. MATERIALS & METHODS: Total of 80 freshly extracted human incisor teeth were selected, sectioned below CEJ and further stained using extra strong black tea and kept for 24 hours. The samples were thoroughly washed and cleaned of external stains and evaluated for pre-shade using spectrophotometer. Samples were divided into groups and bleached using different concentrations, methods and activation systems. Post shades were evaluated and the samples were subjected to statistical analysis. RESULT & CONCLUSION: Carbamide peroxide (15%) used in home bleaching is as effective as 37.5% hydrogen peroxide. On comparing in-office (37.5% hydrogen peroxide) with at-home (15% carbamide peroxide) it can be concluded that home bleaching with higher concentration of carbamide peroxide resulted in a better shade change. 37.5% hydrogen peroxide along with Laser activation resulted in superior immediate results but showed increased rebound of color after 1 week.

Facile Approach to Synthesize and Characterization of Silver Nanoparticles by Using Mulberry Leaves Extract in Aqueous Medium and its Application in Antimicrobial Activity

There is a huge demand of silver nanoparticles in the global market due to their special properties and applications in different fields such as nanomedicine , dentists , nanocatalysis, nanoelectronics, textile field, waste water treatment.The major cons of top down and Bottom up methods are the synthesis processes are highly costly, time consuming and many harmful chemicals are used. To reduce these problems Green chemistry comes to play a very important role for making of silver nanoparticles. Use of various plant extracts like leaves, fruits for synthesis of biogenic silver nanoparticles referred as Green Nanotechnology. In the present work we reported the green synthesis of silver nanoparticles using by Mulberry leaves extract without using any toxic chemicals. The Mulberry leaves extract act as reducing agent as well as a stabilizing agent in green nanotechnology process. The making of silver nanoparticles was determined by the change of shade from white to brownish by the addition of Mulberry leaves extract . UV-Vis absorption spectroscopy was used to monitor the measurable formation of silver nanoparticles showed a maximum peak at 440 nm. High resolution Transmission electron microscope confirmed the spherical nature and the highly crystallinity of silver nanoparticles on an average size 15 -25 nm .Antimicrobial activity of the biogenic Ag nanoparticles was performed by a well diffusion method. The nanoparticles exhibited enhanced anti-bacterial activity when incubated in Escherichia Coli and Bacillus Subtilis cultured plates at varied volumes. Current study thus presents a facile and innovative strategy for synthesis of silver nanoparticles.

Development of water and energy efficient environment friendly easy care finishing by foam coating on stretch denim fabric

Nowadays, intensive use of technology during textile manufacturing is responsible for making the processes more energy intensive. Most of the countries in the world are also facing shortage of pure drinking water. During conventional textile processing such as padding technique, high amount of water is needed to dissolve and apply the required chemicals onto the fabric for the desired performance. The excess usage of water is responsible for the increase in the processing cost as lengthy drying step is needed. In addition, available drinking water is reduced and enormous water effluent is also generated. In this research new environment friendly, formaldehyde free, easy care finishing process is developed by low pick up foam coating technique for stretch denim. The foam stability of the easy care finish was successfully improved by optimizing the thickener and foaming agent. Treated fabric performance was assessed by measuring the crease recovery angle, dry and wet rubbing fastness, shade change after washing, tear strength retention, stretch % and elongation %, stiffness, air permeability and anti microbial. Cost, energy and water efficient foam coated fabric exhibited similar and in some cases improved results as that of padded fabric.

Brønsted acidic ionic liquids: Innovative starch desizing agents

The possibility of using a synthesized inexpensive Brønsted acidic ionic liquids for starch desizing of a textile substrate for the first time was investigated under different conditions in terms of temperature, concentration and treatment time. The samples evaluation was carried out by Fourier transform infrared spectroscopy, microscopic studies, Tegewa tests, measuring weight loss, tensile strength, wetting properties and changes in the samples shades. The results indicated that the ionic liquids have strong effect on the cotton fabric starch desizing (Tegewa 6 or higher) with no adverse effect on the samples strength and whiteness. Thus, it was revealed that proper ionic liquids could be counted as novel starch desizing agents and alternative for the enzymatic process. In addition, it was observed that the acidic ionic liquids because of their specific structure do not have negative aspects of common acidic processes with no sensitivities and drawbacks of enzymatic treatments.

Clinical Evaluation of Genotoxicity of In-office Bleaching.

The aim of this study was to evaluate the genotoxicity of in-office bleaching with 35% hydrogen peroxide in epithelial cells from the gingival and lip tissues. Thirty volunteers with central incisors shade A1 or darker were selected for this study. The gingival tissue of the teeth to be bleached was isolated with a light-polymerized resin dam, and the 35% hydrogen peroxide gel was administered during three 15-minute applications over the course of the 45-minute application period. Two bleaching sessions with a one-week interval in between were performed. Exfoliated oral mucosa gingival epithelial cells and upper lip lining were collected at baseline and one month after the in-office dental bleaching. The scraped cells were placed on clean glass slides and smears were prepared. After staining with Giemsa solution, two blinded examiners performed cell and micronuclei counts under a 100× optical microscope. Tooth sensitivity was evaluated using the Visual Analogue Scale (VAS). Shade evaluation was recorded before and one month after the bleaching treatment with the value-oriented shade guide Vita Bleachedguide 3D-MASTER and the spectrophotometer Vita Easyshade. Data from the shade guide units and the micronuclei (MN) frequency were subjected to a Mann-Whitney test (α=0.05). The overall difference between before and one month after the bleaching treatment (ΔE and ΔSGU), absolute risk, and intensity of tooth sensitivity (TS) were calculated, as was the 95% confidence interval (CI). The frequency of MN was not increased after bleaching with 35% hydrogen peroxide in both study groups (p>0.05). The absolute risk of TS of the participants was 93% (95% CI, 79%-98%), with a mean VAS intensity of 5.7 ± 2.9 (95% CI, 4.6-6.8). Meaningful whitening was observed after bleaching. The change in shade guide units in the Bleachedguide 3D-MASTER was 2.3 ± 1.4. In terms of ΔE, the change in color was 7.7 ± 3.5. The in-office bleaching did not induce DNA damage to the gingival and lip tissue during the bleaching period. Although effective whitening was observed, most of the participants experienced TS.

Comparison of efficacy of tray-delivered carbamide and hydrogen peroxide for at-home bleaching: a systematic review and meta-analysis

The aim of the study was to compare the color change produced by tray-delivered carbamide peroxide [CP] versus hydrogen peroxide products [HP] for at-home bleaching through a systematic review and meta-analysis. MEDLINE via PubMeb, Scopus, Web of Science, Latin American and Caribbean Health Sciences Literature database (LILACS), Brazilian Library in Dentistry (BBO), and Cochrane Library and Grey literature were searched without restrictions. The abstracts of the International Association for Dental Research (IADR) and unpublished and ongoing trial registries were also searched. Dissertations and theses were explored using the ProQuest Dissertations and Periodicos Capes Theses databases. We included randomized clinical trials that compared tray-delivered CP versus HP for at-home dental bleaching. The color change in shade guide units (SGU) and ΔE were the primary outcomes, and tooth sensitivity and gingival irritation were the secondary outcomes. The risk of bias tool of the Cochrane Collaboration was used for quality assessment. After duplicate removal, 1379 articles were identified. However, only eight studies were considered to be at "low" risk of bias in the key domains of the risk bias tool and they were included in the analysis. For ΔE, the standardized mean difference was -0.45 (95% CI -0.69 to -0.21), which favored tray-delivered CP products (p < 0.001). The color change in ΔSGU (p = 0.70), tooth sensitivity (p = 0.83), and gingival irritation (p = 0.62) were not significantly different between groups. Tray-delivered CP gels showed a slightly better whitening efficacy than HP-based products in terms of ΔE, but they were similar in terms of ΔSGU. Both whitening systems demonstrated equal level of gingival irritation and tooth sensitivity. Tray-delivered CP gels have a slightly better whitening efficacy than HP-based products in terms of ΔE. This should be interpreted with caution as the data of ΔSGU did not show statistical difference between the products.

Influence of different pulp capping materials to induce coronal tooth discoloration

AimThis study aimed to evaluate the influence of white MTA, gray MTA, calcium hydroxide and calcium aluminate cement (CAC) in tooth color when used as pulp capping materials. MethodologyExtracted third molars were used (n=50). According to the experimental groups, a 2mm layer was placed in the pulp canal chamber: Group 1 – White MTA; Group 2 – Gray MTA; Group 3 – CAC; Group 4 – calcium hydroxide paste followed by calcium hydroxide cement. In the control group white gutta-percha was used. Vestibular, lingual, mesial and distal color readout was performed at baseline and after 30 days. Images were captured using a digital camera Nikon D80 and shade evaluation performed using Photoshop 7.0. The blue channel in red, green and blue color mode (RGB) was used to measure chromatic changes in a scale from 0 (darkest) to 255 (lightest). The data were evaluated by univariate analysis. ResultsAll teeth showed some discoloration after 30 days. The mean variation of pixel intensity for the blue channel was similar between groups. However, considering the mean pixel intensity for the blue channel after 30 days, teeth where CAC was used were significantly darker than those from the control group. ConclusionsThis study demonstrated that all tested materials induced teeth shade changes after 30 days of simulated pulpotomy. The mean variation of color was similar between groups and CAC caused the higher color change.

Effect of low-level laser therapy on tooth sensitivity induced by in-office bleaching.

This study aimed to investigate the effect of low-level laser therapy (LLLT) on tooth sensitivity induced by in-office bleaching. Sixty-six patients enrolled in this randomized clinical trial. Following the in-office procedure with 40% hydrogen peroxide, the participants were randomly divided into three groups. The patients in group 1 received irradiation from a low-level red laser (LLRL; 660 nm, 200 mW, 15 s, 12 J/cm(2)), whereas participants in group 2 were subjected to a low-level infrared laser (LLIL; 810 nm) under similar conditions as in group 1. In group 3 (placebo), the laser treatment was the same as that in groups 1 and 2, but without energy output. The degree of tooth sensitivity was recorded at 1, 24, and 48 h after bleaching using a visual analog scale (VAS). The change in tooth shade was measured 30 days after tooth whitening. The intensity of tooth sensitivity was not significantly different between groups at 1 h after bleaching (p > 0.05). At 24 h after therapy, pain level was significantly lower in the LLIL group compared to the LLRL and placebo groups (p < 0.05). At 48 h after bleaching, VAS scores in the LLIL and LLRL groups were comparable to each other (p > 0.05) and both were significantly lower than that of the placebo group (p < 0.05). There was no significant difference in the efficacy of tooth whitening among groups (p > 0.05). LLLT with an infrared diode laser could be recommended as a suitable strategy to reduce the intensity of tooth sensitivity after in-office bleaching.

Climate and land cover effects on the temperature of Puget Sound streams

AbstractWe apply an integrated hydrology‐stream temperature modeling system, DHSVM‐RBM, to examine the response of the temperature of the major streams draining to Puget Sound to land cover and climate change. We first show that the model construct is able to reconstruct observed historic streamflow and stream temperature variations at a range of time scales. We then explore the relative effect of projected future climate and land cover change, including riparian vegetation, on streamflow and stream temperature. Streamflow in summer is likely to decrease as the climate warms especially in snowmelt‐dominated and transient river basins despite increased streamflow in their lower reaches associated with urbanization. Changes in streamflow also result from changes in land cover, and changes in stream shading result from changes in riparian vegetation, both of which influence stream temperature. However, we find that the effect of riparian vegetation changes on stream temperature is much greater than land cover change over the entire basin especially during summer low flow periods. Furthermore, while future projected precipitation change will have relatively modest effects on stream temperature, projected future air temperature increases will result in substantial increases in stream temperature especially in summer. These summer stream temperature increases will be associated both with increasing air temperature, and projected decreases in low flows. We find that restoration of riparian vegetation could mitigate much of the projected summer stream temperature increases. We also explore the contribution of riverine thermal loadings to the heat balance of Puget Sound, and find that the riverine contribution is greatest in winter, when streams account for up to 1/8 of total thermal inputs (averaged from December through February), with larger effects in some sub‐basins. We project that the riverine impact on thermal inputs to Puget Sound will become greater with both urbanization and climate change in winter but become smaller in summer due to climate change. Copyright © 2016 John Wiley &amp; Sons, Ltd.

Development and implementation of the Clinical Tooth Shade Differentiation Course--an evaluation over 3 years.

Objective: Tooth shade differentiation concerns the identification and classification of tooth shades. The objective of this project was to implement the Clinical Tooth Shade Differentiation Course in the preclinical stage of studies and to evaluate the students' perspective over a period of 3 years.Methodology: The course is planned for a duration of 10 weeks with two 45-minute sessions per semester week. The entire attendance time was 10:15 h. 2 lectures of 90 minutes each, 2 seminars of 60 min each and 2 teaching units with the phantom head and role playing took place. In addition to the various parameters of tooth shade, changes in tooth shade and the basics of dental esthetics, clinical procedures for manual and digital tooth shade determination were explained and practiced. 96% (69 of 72) of the students participated in the first evaluation in 2012/2013 (T1), and 68% of these were women. In the following year, 2013/2014 (T2), 92% (45 of 48 students) took part; 62% of these were women and 38% men. The 2014/2015 evaluation (T3) comprised 94% (45 of 48 students). Of these, 67% were women.Results: In the evaluation, the students gave the course a positive grade. The questions in "General/Organization" were given a mean (M) of 1.5 (SD=0.7) in T1 and T2 , and 1.2 (SD=0.3) in T3. The "Overall Assessment" yielded MT1=1.6 (SD=0.6), MT2=1.5 (SD=0.5) and MT3=1.1 (SD=0.3). In T1 and T2, the item "The instructor actively involved the students in the course" was given a mean of 2.1 (SD=0.9), and in T3 a mean of 1.2 (SD=0.5). Conclusions: The course presented here conceptually shows how practical dental skills can be taught in a theoretical and clinical context. Educational objectives from the role of a dental expert were taken from the national competence-based catalog of educational objectives for dentistry and can also be supplemented. The objectives can be transferred to other dental faculties.

Graded changes in enamel component volumes resulted from a short tooth bleaching procedure

AimTo test the hypothesis that changes in enamel component volumes (mineral, organic, and water volumes, and permeability) are graded from outer to inner enamel after a short bleaching procedure. Materials and methodsExtracted unerupted human third molars had half of their crowns bleached (single bleaching session, 3×15min), and tooth shade changes in bleached parts were analyzed with a spectrophotometer. Ground sections were prepared, component volumes and permeability were quantified at histological points located at varying distances from the enamel surface (n=10 points/location), representing conditions before and after bleaching. ResultsTooth shade changes were significant (p<0.001; 95% CI=−1/−8; power=99%), and most of the enamel layer was unaffected after bleaching, except at the outer layers. Multiple analysis of covariances revealed that most of the variance of the change in enamel composition after bleaching was explained by the combination of the set of types of component volume (in decreasing order of relevance: mineral loss, organic gain, water gain, and decrease in permeability) with the set of distances from the enamel surface (graded from the enamel surface inward) (canonical R2=0.97; p<0.0001; power>99%). ConclusionsChanges in enamel composition after a short bleaching procedure followed a gradient within component volumes (mineral loss>organic gain>water gain>decrease in permeability) and decreased from the enamel surface inward.

Evaluation of the whitening and remineralization effects of a mixture of amorphous calcium phosphate, hydroxyapatite and tetrasodium pyrophosphate on bovine enamel

Objectives: The purpose of the present study was to evaluate the whitening effect, morphological and structural changes, and remineralization of the enamel induced by 3 combined agents: amorphous calcium phosphate (ACP), hydroxyapatite (HA), and tetrasodium pyrophosphate (TSP). Methods: The study was performed on 90 bovine enamel slabs, which were divided into the 6 groups: negative control-distilled water (Group 1); positive control-opalescence F (Group 2); 10% mixed agent (Group 3); 25% mixed agent (Group 4); 50% mixed agent (Group 5); and 100% mixed agent (Group 6). Changes in the shade of the enamel slabs were evaluated using Shade Eye-NCC. Morphological changes were assessed by scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) was used to determine the remineralizing effect of the three agents on enamel slabs. Results: The change in shade of the enamel (ad*) was noted to increase significantly with increase in whitening frequency in all groups. The value of Δn* was significantly greater in all groups except for the negative control group (P<0.001). SEM revealed that the control group, Group 5, and Group 6 had similar morphologies. The fluorescence lesion areas in the 4 mixture-treated group were significantly smaller than those in the positive control group (P<0.001). Conclusions: These results showed that the mixture of ACP, HA, and TSP was highly effective for bovine enamel whitening and acted by inducing the remineralization of enamel. Clinical significance: We evaluated the applicability of a new mixture containing ACP, HA, and TSP. This mixture would be highly useful in aesthetic dentistry because of its whitening efficiency, which does not compromise the enamel’s integrity.

Evaluation of the Diode laser (810nm, 980 nm) on color change of teeth after external bleaching.

Subject and aim: The aim of this study was to evaluate the efficiency of diode laser-activated bleaching systems for color change of teeth. Materials & Methods: 40 premolars with intact enamel surfaces were selected for five external bleaching protocols (n=8). Two different wavelengths of diode laser (810 and 980 nm) with two different hydrogen peroxide concentrations (30% and 46%) were selected for laser bleaching. Group 1 received bleaching (Heydent- Germany) with a 810 nm diode laser; Group 2 received bleaching (Heydent- Germany) with a 980 nm diode laser; Group 3 received bleaching (laser white*20- Biolase) with a 810 nm diode laser; Group 4 received bleaching (laser white*20- Biolase) with a 980 nm diode laser, with an output power of 1.5 W, in continuous wave (cw) mode for each irradiation. Group 5 as control group received 40% hydrogen peroxide (Opalescence Boost, Ultradent-USA) with no light activation. The color of teeth was scored at baseline and 1 week after bleaching with spectrophotometer. Color change data on the CIEL*a*b* system were analyzed statistically by the one-way ANOVA and Tukey's HSD test. Results: All the bleaching techniques resulted in shade change. According to ΔE values, all techniques were effective to bleach the teeth (ΔE ≥ 3). Statistically significant differences were detected among bleaching protocols (p=0.06). Regarding shade change values expressed as ΔL*, Δa*, Δb*, ΔE*, laser bleached groups were no statistically different with each other (p>0.05). Conclusion: Bleaching with different wavelengths of diode laser resulted in the same results.

Predictive factors on the efficacy and risk/intensity of tooth sensitivity of dental bleaching: A multi regression and logistic analysis

ObjectivesThe aim of this study was to identify predictor factors associated with the whitening outcome and risk and intensity of bleaching-induced tooth sensitivity from pooled data of 11 clinical trials of dental bleaching performed by the same research group. MethodsThe individual patient data of several published and ongoing studies about dental bleaching was collected and retrospectively analyzed. At the patient-level, independent variables (bleaching techniques [at-home and in-office protocols], sex, age and baseline tooth color in shade guide unit [SGU]) as well as dependent variables (color change in shade guide units (ΔSGU), color change in the CIEL*a*b* system (ΔE), risk and intensity of TS in a visual analog scale) were collected. Multivariable linear regression and multivariable logistic regression models were carried out using backward elimination whenever the p-values were higher than 0.05. ResultsA significant relationship between baseline color and age on color change estimates was detected (p<0.001). Every increase of one SGU in the baseline color resulted in an increase of approximate 0.66 in the final ΔSGU and 2.48 for the ΔE. For every increase of one year in the participant’s age we observed a decrease of the whitening degree of 0.07 for the final ΔSGU and 0.69 for the ΔE. The bleaching technique was shown to be a significant predictor of ΔSGU (p<0.001) but not of ΔE. In regard to TS, baseline color and bleaching technique are significant predictors (p<0.001). The risk of TS for at-home bleaching was 51% (95% CI 41.4–60.6) and for the in-office 62.9% (95% CI 56.9–67.3). ConclusionsYounger patients with darker teeth reach a higher degree of whitening. Patient with darker teeth and submitted to at-home bleaching presents lower risk and intensity of TS. Clinical significanceThe baseline color of the teeth and the patient’s age is directly related to the effectiveness of dental bleaching and TS.

Effect of toothbrushing on shade and surface roughness of extrinsically stained pressable ceramics

Statement of problemThe effect of toothbrushing on extrinsically stained pressable ceramic materials is unknown. PurposeThe purpose of this in vitro study was to investigate the effects of toothbrushing on the shade and surface roughness of extrinsically stained, pressable ceramics. Material and methodsTwo materials, leucite-based (IPS Empress Esthetic [EE]; Ivoclar Vivadent AG) and lithium disilicate-based ceramic (IPS e.max Press [EP]; Ivoclar Vivadent AG), were studied. For each material, 24 disk-shaped specimens, 10 mm (diameter)×3 mm (height) were fabricated. Three different methods (n=8) of applying extrinsic stains were performed on each material: glazed only (G, control group); stained then glazed (SG); and stained and glazed together (T). The specimens were brushed with a multistation brushing machine under a load of 1.96 N at a rate of 90 strokes per minute with a soft and straight toothbrush (Oral-B #35) and a 1:1 toothpaste and distilled water slurry. Shade and roughness were measured at baseline and at 72, 144, 216, and 288 hours, which is equivalent to 3, 6, 9, and 12 years of simulated toothbrushing for 2 minutes twice a day. A repeated measures ANOVA with staining technique as a fixed factor was used to evaluate shade and roughness (α=.05). ResultsFor EE groups, no significant change was found after 12 years of simulated toothbrushing regarding shade and surface roughness, irrespective of staining techniques (P>.05). However, EP groups demonstrated a significant shade change and an increase in surface roughness after 12 years of simulated toothbrushing. Shade change was found to depend on the method of applying stain. For the EP-SG technique, a significant shade change was observed only at the 9- to 12-year interval (P=.047). However, the EP-T technique demonstrated a significant difference in shade between baseline and 3 years (P=.005) and in the 6- to 9-year interval (P=.005). Surface roughness was only significantly affected at baseline and 3 years for the EP-T group (P=.005). ConclusionsFor the shade and surface roughness of the EE groups, no statistically significant difference was found after 12 years of toothbrushing, irrespective of the staining technique. The shade and surface roughness of the EP groups were significantly statistically affected by toothbrushing time; only shade changes were found to depend on technique.

Assessment of efficacy and post-bleaching sensitivity of home bleaching using 10% carbamide peroxide in extended and non-extended bleaching trays.

This study aimed to compare the effect of extended margin and conventional bleaching trays on tooth bleaching and tooth sensitivity. METHOD AND METHODS: Twenty subjects (18-56 years) were investigated in a split arch design clinical study that was conducted in a general dental practice. Each subject received a custom made bleaching tray and 10% carbamide peroxide gel. The bleaching trays had the borders extended 5 mm beyond the gingival margins on the right side and finished just at the gingival margin on the left side. Shade change and tooth sensitivity were the primary outcomes studied and analysed in this study. The shade of the six upper and lower anterior teeth was assessed using a value-ordered shade guide before, one week and two weeks after treatment. Sensitivity was self-assessed using a visual analogue scale (VAS) at the end of the first and second weeks of the study. At the end of week two, the mean shade change was 5.01 (± 3.37) and 5.10 (± 3.36) for teeth covered by extended and non-extended tray design, respectively. The mean VAS sensitivity scores for teeth covered by extended and non-extended tray design were 0.96 (± 1.39) and 0.66 (± 0.96), respectively. There was no significant statistical difference between the two designs at any assessment point with regard to shade change and sensitivity (p >0.05). It can be concluded that an extended tray design confers no superior effect in terms of the whitening outcome achieved or in reducing levels of sensitivity. Thus, both tray designs can be used depending on a dentist's personal preference.

Durabilidade pós-produção de vasos de três espécies de Kalanchoe (Crassulaceae) em diferentes substratos

Potted plants have wide appeal among ornamental plants and one of the most produced for the market belong to the genus Kalanchoe. One aspect to be observed in potted plants is their durability post-production when maintained in indoors conditions as offices and homes. This study aimed to evaluate the durability of the pot post-production life of three species of Kalanchoe (K. marmorata, K. thyrsiflora and K. tubiflora) on different substrates. The experiment was arranged in a completely randomized design with 40 replicates per treatment in factorial 3 x 2 (three species of Kalanchoe x two substrates - washed sand and coconut fiber). After 30 days, it was evaluated the general aspects as changes in color, leaf abscission and shading of the stem apex. It was found significant differences between species and also between the substrates tested, but only in relation to the general aspects. The species Kalanchoe marmorata and K. tubiflora stood out by receiving top grades in most of the evaluated characteristics. The best substrate that provided plants the maintenance of the most of their ornamental characteristics over the 30 days was the coconut fiber.

The effect of gum chewing on sensitivity associated with in-office whitening procedures.

Tooth sensitivity is the most common side effect of in-office tooth-whitening procedures. The purpose of this study was to determine whether chewing gum containing 0.6% casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) before tooth whitening would reduce tooth sensitivity during an in-office whitening procedure. Thirty participants were enrolled and randomized into three groups as follows: group 1 was instructed to not chew gum during the study period; group 2 chewed five pieces of gum (with 0.6% CPP-ACP) for 10 min each day 1 week before whitening; and group 3 chewed five pieces of gum (without CPP-ACP) for 10 min each day 1 week before whitening. All participants had their teeth whitened with a 30% hydrogen peroxide in-office whitening procedure. The participants' shades of teeth were evaluated with a spectrophotometer four times during the study: at the initial screening visit, immediately before whitening, immediately after whitening and 1 week after whitening. Participants' sensitivity levels were evaluated each time the shades were evaluated and additionally at 24 h after whitening using a 100-mm visual analogue scale. Thirty participants were enrolled in the study. The average shade change was -2.27 (± 2.07). The average sensitivity for all groups at visit 1 was 5.12 (± 13.94). The average sensitivity for all groups after whitening was 19.81 (± 13.95). There were significant differences in sensitivity between groups 2 and 3 (P = 0.02), but neither group was significantly different from the control group (P = 0.86, P = 0.07). Chewing gum before whitening, including gum with CPP-ACP, did not reduce sensitivity during in-office whitening procedures.