Bleaching Treatment Research Articles

Extraction and Characterization of Inherently Antimicrobial Fibres from Aerial Roots of Banyan Tree

ABSTRACT Aerial roots of the Banyan tree were utilized to extract completely biodegradable natural fibers with inherent antimicrobial properties which can be used as potential raw material for health and hygiene products. Fiber extraction conditions were optimized for biological, chemical and enzymatic treatments. Bleaching and softening treatments were given for improving color, further individualization and enhancing handle of extracted fibers. The change in chemical composition due to alkali treatment was determined using FTIR. SEM was used to compare the change in surface morphology of fibers with the use of different treatment. Various physical and biological properties of the fibers were tested and compared with other lignocellulosic fibers. It was observed that the physical properties of fibers extracted from aerial roots of banyan tree were comparable to other natural cellulosic fibers like sisal, coir, jute. The fibers have a combination of properties such as low strength, moderate elongation along with good moisture regain and retention. Additionally, they exhibit excellent resistance against bacterial and fungal growth, which is quite rare in case of natural cellulosic fibers, making them suitable for potential usage, especially in hygiene products. Other applications in terms of fiber composites with suitable materials can also be envisaged.

ANALISIS PENGARUH PERLAKUAN KIMIA TERHADAP MORFOLOGI DAN GUGUS FUNGSIONAL SERAT SISAL

Morphological and functional group analysis was carried out to study the appearance of micro and molecular structures contained in sisal fibers before and after chemical scouring and bleaching treatment. The scouring and bleaching process lasts for 1 hour with continuous stirring using a magnetic stirrer. Scouring was carried out with 6% NaOH solution while Bleaching was carried out with a solution of 10 g / L NaOH and 100 ml / L H2O2. Scanning Electron Microscopy (SEM) was used to identify the surface appearance and diameter of the fibers before and after the scouring and bleaching processes. Fourier transform infrared (FTIR) spectroscopy is used to identify functional groups in fibers. The Bleaching process shows that the functional groups identified are the same as those of pure cellulose or alpha cellulose, namely -CH2, C-O, C = C, -CH3, C?C, and -OH, C-H. Sisal fibers with a diameter between 100 - 150 µm break down (fibrillate) into smaller fibers after the scouring (diameter: ?12 µm) and bleaching (diameter: ?7µm) processes. Thus, scouring and bleaching have caused significant changes in the morphological and microstructure of the fiber surface and also the functional groups that the sisal fiber has after the bleaching process is the same as pure fiber.

Combination of strontium chloride and photobiomodulation in the control of tooth sensitivity post-bleaching: A split-mouth randomized clinical trial.

ObjectiveThis split-mouth randomized controlled clinical trial assessed the effect of 10% strontium chloride in combination with photobiomodulation (PBM) for the control of tooth sensitivity (TS) post-bleaching.MethodsThe upper/lower, right and left quadrants of fifty volunteers were randomized and allocated to four groups (n = 25): PLACEBO—placebo gel + simulation of PBM; Placebo + PBM; STRONTIUM—10% strontium chloride + simulation of PBM; and PBM + STRONTIUM—10% strontium chloride + PBM. All groups received tooth bleaching treatment with 35% hydrogen peroxide. For the PBM treatment, the laser tip was positioned in the apical and cervical regions of the teeth bleached in the respective hemi-arch. The laser system was operated in continuous mode, using 1.7 J of energy. A dose of 60 J/cm2 was applied to each point for 16 seconds under 808 nm near-infrared light (100mW of power), with a point area of 0.028 cm2. TS was assessed during a 21-day follow-up, using the modified visual analogue scale.ResultsIn the intragroup assessment, the Friedman test indicated that PBM + STRONTIUM promoted the greatest reduction in TS after the second week of treatment (p ≤ 0.05). The Wilcoxon-Mann-Whitney test indicated that the groups Placebo + PBM, STRONTIUM, and STRONTIUM + PBM did not differ statistically (p ≥ 0.05) in the first and third weeks of treatment The group PLACEBO exhibited the greatest TS in the first three days after each bleaching session.ConclusionThe combination of 10% strontium chloride with PBM was effective in reducing post-bleaching TS; however, the combination of 10% strontium chloride with PBM was effective in reducing post-bleaching TS; however, it did not differ from the individual use of Placebo + PBM or STRONTIUM groups assessed after 21 days of follow-up.

Effect of pH of H2O2 solutions on the morphology and wear resistance of human dental enamel: an AFM study

Introduction Teeth whitening is a highly demanded aesthetic dental procedure to remove teeth stains and get a whiter and perfect smile. This type of treatment is usually performed by the application on the teeth surface of hydrogen or carbamide peroxides which diffuse through the external layer of the teeth, enamel [1]. Although whitening treatments improve teeth appearance, they can impair teeth health, due to the eventual degradation of the teeth tissues. This may lead to abnormal wear and weaken the tooth structure. The aim of this work is to study the effect of the pH of 30% H2O2 solutions on the surface of human enamel. Materials and methods Human molars were collected for the study with informed consents of the patients. Teeth were bleached in 30% H2O2 solution with different pH values (2, 4 and 6). All samples were submitted to 11 bleaching sessions of 10 min each with alternate periods (2 min) of exposition to blue light. Microhardness, surface roughness and topography/morphology were characterised by microindentation tests, atomic force microscopy (AFM) and scanning electron microscopy (SEM), respectively, before and after the whitening treatments. AFM scratching tests (10 × 10 µm2) were performed, using a diamond probe. After the nanowear tests, topographical images of larger areas (20 × 20 µm2) which include the scratched squares were obtained with a silicon probe. The wear mechanisms were evaluated by SEM. Acceptance of the study protocol was obtained from a local ethics committee. Results The most significant changes on enamel surface were obtained for pH = 2: the microhardness decreases, and the surface roughness significantly increases as confirmed by the SEM image analysis. A higher wear rate was observed for pH = 2 in the AFM scratching tests. SEM observation of the wear zone showed differences in the wear mechanisms, which depend on the pH. Discussion and Conclusions Enamel microhardness, surface roughness and wear resistance are affected by the pH of the bleaching solution: pH = 2 led to the most adverse effects, which was attributed to hydroxyapatite demineralisation. The study of the effect of pH in the bleaching treatments is crucial to optimise this type of procedures and avoids enamel damage.

Effect of an antioxidant on the microtensile bond strength (µTBS) of restored teeth after dental bleaching

Introduction Dental bleaching is regarded as a safe medical treatment for those who want to achieve a brighter smile. Bleaching is a chemical process in which oxidation occurs, affecting the way teeth absorb or reflect light [1]. Oxidative ability of bleaching agents and the presence of free hydroxyl radicals in the apatite modifies the mineral and protein composition of the enamel increasing its solubility. This renders the enamel surface adverse to the best bonding conditions [2,3]. Some strategies, including antioxidants such as sodium ascorbate, are capable of re-establishing the bond strength to nearest normal values, showing to be an effective method when used immediately after dental bleaching treatment [4,5]. The purpose of this study is to evaluate the effect of an antioxidant on the microtensile bond strength of bleached teeth that were subsequently restored, comparing different waiting times for the procedure. Materials and methods Thirty human permanent molars were sectioned into halves (n = 60), and randomly distributed between three groups: control (CG), bleaching (G1) and bleaching + sodium ascorbate (G2). Groups G1 and G2 were bleached 2 h/day for a 7-day period. After bleaching, G2 received a 10% sodium ascorbate gel for 50 min. In each group, samples were divided in equal parts where one part (n = 5) was immediately restored with an adhesive system and a resin composite (T0) and the other half (n = 5) was stored, in artificial saliva at 37 °C, and restored after 7 days (T1). After 24 h, samples were sectioned into microspecimens (∼1mm2) and tested at a crosshead head-speed of 0.5 mm/min. Data analysis was performed using a factorial ANOVA, at a significance level of 5%. Results Groups in which sodium ascorbate was applied presented mean µTBS values (G2T0: 22.1 ± 3.3 MPa; G2T1: 24.5 ± 2.9 MPa) significantly higher than the bleaching only and immediately restored group (G1T0, 10.9 ± 3.3 MPa) (p < .001). The group in which teeth were beached and restored after 7 days (G1T1, 19.4 ± 2.6 MPa) showed significantly higher values than the group immediately restored after bleaching (G1T0) (p = .006). No significant differences were found between the groups in which sodium ascorbate was applied (G2) and the group in which teeth were bleached and restored after 7 days (G1T1) (p > .05). Discussion and conclusions Sodium ascorbate is capable of capturing free oxygen radicals retained on the enamel. These promote decomposition of hydrogen peroxide, which in turn prevents the complete polymerisation of the adhesive system thus affecting bond strength [2,5]. The application of sodium ascorbate is an effective alternative to improve bond strength when compared to a waiting period before the restorative procedure.

A comparative analysis of in-office vital 6% hydrogen peroxide activated charcoal tooth whitening treatment enhanced with an 810nm diode laser, compared to 35% hydrogen peroxide bleaching

Laser dental bleaching is considered to be a contemporary approach to enhancing the in-office power bleaching procedure.&#x0D; Objective&#x0D; Investigate if laser enhanced 6% Hydrogen Peroxide (HP) solution is equivalent to 35% HP solution over a two-visit power bleaching treatment protocol. In a randomised double-blinded clinical trial, 43 patients were assigned to a group that received either the laser-enhanced 6% Hydrogen Peroxide (n=21) treatment, or the standard 35% Hydrogen Peroxide (n=22) treatment, over two visits, with a one-week interval. Activated charcoal HP paste was prepared for both groups. The laser enhanced 6% HP group received a dosage of 90 J/cm² per bleaching cycle using 810nm diode laser. Tooth colour was measured at the beginning and end of each session registering parameters L*, a* and b*, and tooth sensitivity. The calculated difference between these Parameters, ∆E, was the primary data focus. The mean ∆E over the treatment duration was used to answer the research question by a t-test to evaluate group differences at 5% significance level. The analysis revealed that the null hypothesis could not be rejected and the results were inconclusive. The observations expound the idea of an absorption enhancement mechanism, rather than a free radical activation, as the technique for improving bleaching outcomes.

Spectrophotometric evaluation of the effectiveness of Er,Cr:YSGG laser-assisted intracoronal tooth bleaching treatment using different power settings

BackgroundNon-vital tooth discoloration is a common condition in dental practice. The aim of this in vitro study was to evaluate the efficacy of intracoronal bleaching treatments of non-vital teeth either activated or not by Er,Cr:YSGG laser (2780 nm) operating at 1.25 or 2.5 W. MethodsTwenty four human canines were artificially stained after implementation of root canal treatment. Subsequently, the teeth were randomly divided into three groups (n = 8): Group 1 (control) received intracoronal bleaching treatment with a bleaching gel containing 35 % hydrogen peroxide for 40 min, Group 2 received the same treatment assisted with Er,Cr:YSGG laser (2780 nm) operating at 1.25 W average power for 30 s and Group 3 received the same treatment with Group 2, but the average power was adjusted to 2.5 W. The bleaching treatments repeated after one week. Spectrophotometric analysis of tooth color change (ΔE) was implemented 7 days after both bleaching sessions. ResultsThe results of two-way ANOVA revealed that there was a tendency of no significant difference in color change between the three experimental groups (p = 0.063). However, the between-group comparisons showed that laser 2.5 W group had significantly higher ΔE than the control group after the first bleaching session. Moreover, a significant interaction between bleaching treatment and number of applications was detected (p = 0.026). ConclusionsEr,Cr:YSGG laser irradiation significantly increased ΔE only after the first bleaching session when operating at 2.5 W. After the second bleaching session ΔE was not different compared to the control group, irrespectively of the laser power settings.

English

BACKGROUND Dental appearance influences the facial aesthetics that includes smile harmony, tooth colour, shape, arrangement and visibility. METHODS The current study aims to identify and evaluate factors affecting patients' satisfaction towards the appearance of teeth &amp; gums; and dental treatments that facilitate facial and dental aesthetics. 300 patients were surveyed with a questionnaire containing close-ended questions on their gender, age, education, tooth appearance, orthodontic and teeth whitening treatments, tooth &amp; gum-related problems and satisfaction levels towards dental and facial aesthetics. Chi-square test and logistic regression analysis were performed on the collected data. RESULTS A majority (76 %) of the study population desired to undergo bleaching treatment for teeth whitening. 70 % of the respondents also wish for composites, while only 40 % desired orthodontic appliances. Satisfaction with dental appearance is significantly found to affect facial appearance. Also, similar to dental appearance, there is a statistically significant relation between the desire for tooth bleaching, orthodontic appliance, and composites and satisfaction towards facial appearance. Satisfaction with gingival appearance, tooth-colour, and satisfaction with smile appearance are found to affect the satisfaction towards facial appearance. CONCLUSIONS Tooth colour was observed to be a crucial aspect that affects the overall dental aesthetics and satisfaction levels of the participants. It was realized from this investigation that dental care, better hygiene and treatments for improving dental aesthetics are relevant for patients’ satisfaction regarding overall facial appearance and aesthetics. KEY WORDS Dental Aesthetics, Facial Aesthetics, Orthodontic Treatment, Tooth Whitening

Intra‐Valve Elemental Distributions in Arctic Marine Ostracodes: Implications for Mg/Ca and Sr/Ca Paleothermometry

AbstractReconstructing intermediate and bottom‐water temperature in the Arctic Ocean is key for understanding paleoclimatic phenomena, such as the region's interactions with warm Atlantic waters, stratification, and sea‐ice dynamics. However, benthic proxy archives are sparse throughout the Arctic circle compared to lower latitudes. Trace‐element ratios (E/Ca) derived from ostracodes, a group of bivalved microscopic crustaceans, have shown promise in this regard. Samples for E/Ca measurements typically require rigorous cleaning prior to analysis, and signs of contamination are routinely monitored through the presence of other trace elements such as Al, Fe, and Mn, which are associated with suspected sources of overprinting. However, there has not yet been an intra‐valve investigation of all of these trace elements, which may hinder our ability to effectively identify geochemical overprinting. Here, we present several elemental concentration and E/Ca ratio measurements in two ostracode genera, Krithe and Polycope, extracted from Chukchi Sea sediment samples. We further investigate the intra‐valve distribution of elements within single shells of adult and juvenile specimens using electron probe microanalysis (EPMA). Our findings suggest that brushing and bleach treatments may not be effective for completely eliminating clays from the edges of valves, which can bias paleoclimatologically relevant trace‐element proxies such as Mg/Ca ratios, particularly in the case of incomplete or small samples with low amounts of calcite material. In addition, we report the first trace‐element data from the genus Polycope, which shows potential as a new Arctic paleotemperature archive.

Effect of diode laser-assisted bleaching on the bond strength of different adhesive systems to enamel: Interfacial SEM analysis.

The aim of this study was to investigate the effectiveness of diode laser-assisted bleaching on the shear bond strength (SBS) of different adhesive systems to enamel and examine the adhesive enamel interface under scanning electron microscope (SEM). 180 incisor teeth were randomly divided into three bleaching groups: (1) Unbleached control group, (2) Opalescence Boost (OB) 40%, and (3) Diode laser-assisted LaserWhite20 (LW20) 45%. After bleaching, each group was divided into two subgroups according to waiting time: immediately or 7 days' delay. The six groups were then divided into three subgroups based on the adhesive procedure: Single Bond 2 (SB2), Clearfil SE Bond (CSB), and Clearfil Universal Bond (CUB). After adhesive procedures, composite resin cylinders were bonded to the enamel surfaces. All specimens were subjected to a SBS test after 24 hr of storage in water. Data were analysed using three-way variance analysis (p < .05). Specimens were examined under a stereomicroscope and SEM. There was a significant difference between the groups bonded immediately and 7 days after bleaching (p < .05). SB2 after 7 days showed the highest SBS values (19.24 ± 2.18), whereas CUB showed the lowest values in both bleaching treatments and control groups (10.84 ± 1.66). SEM analysis of the unbleached specimens revealed long tags and uniform hybrid layer compared OB and LW20 bleaching groups. LW20 and OB bleaching adversely affected SBS to enamel when bonded immediately. Diode laser-assisted bleaching might be an alternative option due to the short working time but delaying bonding for 7 days after bleaching may not be enough for ideal adhesion. RESEARCH HIGHLIGHTS: Bleaching agents containing high concentration hydrogen peroxide reduces the enamel bond strength of adhesive systems. Postponing composite restorations for 7 days after bleaching may not be sufficient to achieve ideal adhesion. Diode laser-assisted bleaching may be preferred as an alternative bleaching method today due to its ability to shorten the operation time and cause minimal morphological changes on the enamel surface.

Preparation of palm (Elaeis oleifera) pressed fibre cellulose nanocrystals via cation exchange resin: characterisation and evaluation as Pickering emulsifier.

Palm pressed fibre (PPF) is a cellulose-rich biomass residue produced during palm oil extraction. Its high cellulose content allows the isolation of cellulose nanocrystal (CNC). CNC has attracted scientific interest due to its biodegradability, biocompatibility and low cost. The present study isolated CNC from PPF using a cation exchange resin, which is an environmentally friendly and less harsh hydrolysis method than conventional mineral acid hydrolysis. Isolated CNC was used to stabilise an oil-in-water emulsion and the emulsion stability was evaluated in terms of droplet size, morphology and physical stability. PPF was subjected to alkali and bleach treatment prior to hydrolysis, which successfully removed 54% and 75% of non-cellulosic components (hemicellulose and lignin, respectively). Hydrolysis conditions of 5h, 15:1 (w/w) resin-to-pulp ratio and 50°C produced CNC particles of 50-100 nm in length. CNC had a crystallinity index of 42% and appeared rod-like morphologically. CNC-stabilised emulsion had better stability when used in combination with soy lecithin (SL), a well-established, commonly used food stabiliser. Emulsion stabilised by the binary mixture of CNC and SL had droplet size, morphology and physical stability comparable to those of emulsion stabilised using SL. CNC was successfully isolated from PPF through a cation exchange resin. This offers an alternative usage for the underutilised PPF to be converted into value-added products. Isolated CNC was also found to have promising potential in the stabilisation of Pickering emulsions. These results provide useful information indicating CNC as a natural and sustainable stabiliser for food, cosmeceutical and pharmaceutical applications. © 2021 Society of Chemical Industry.

Assessment of the aesthetic impact and quality of life of home dental bleaching in adult patients.

BackgroundThis study aimed to evaluate the impact of home bleaching with 10% carbamide peroxide on the quality of life and aesthetic perception of patients. Material and MethodsA total of 107 patients between 18 and 38 years of age with good oral and general health and at least one anterior tooth in color A2 or darker were selected. Patients who previously underwent any type of bleaching procedures were excluded. All patients received a home bleaching treatment with 10% carbamide peroxide. Before beginning the bleaching treatment, the selected patients responded a form with the Oral Health Impact Profile short form (OHIP-14) and Oral Aesthetic Subjective Impact Scale (OASIS) questionnaire. One month after the bleaching treatment, the patients answered the same questionnaires again. The mean ΔE after bleaching was obtained for the canines and lateral and central incisors. The OHIP-14 and OASIS data were measured for the total sample before and after bleaching using the Wilcoxon signed-rank test with a 5% significance level. ResultsThe effectiveness of whitening by significant color variation was observed in all groups of teeth with less variation in ΔE for central incisors. Comparing before and after bleaching, there was no significant difference in impact for any of the seven domains and total OHIP-14 scores, although a decrease was observed in the discomfort and psychological disability domains. As for the self-perception of dental aesthetics, measured by the OASIS, there was also no significant difference for all the items evaluated; however, it was possible to observe an increase in “concern with dental appearance” after bleaching. ConclusionsHome bleaching with 10% carbamide peroxide did not have a significant impact on patients’ quality of life and aesthetic perception, although there was a decrease in the domain of psychological discomfort and an increase in concerns about dental appearance. Key words:Tooth Bleaching, quality of life, self-perception, dental aesthetics.

Triple-blinded randomized clinical trial comparing efficacy and tooth sensitivity of in-office and at-home bleaching techniques.

Objective Our study aims to compare the efficacy and tooth sensitivity following in-office (35% hydrogen peroxide) or at-home (10% carbamide peroxide) bleaching treatments both preceded by 2% potassium nitrate (2%KF) desensitizing gel.Methodology 130 volunteers were randomly allocated to a) in-office bleaching and a placebo at-home protocol; or b) in-office placebo and at-home bleaching treatment. 2% KF was applied for 10 min before both treatments.Objective color evaluation was performed (spectrophotometer CIEL*a*b* system and CIEDE2000) to calculate the color change (ΔE00). Subjective evaluation was performed using the VITA classical shade guide followed by shade variation (ΔSGU) at the beginning and end of bleaching treatment and 2 weeks post-bleaching. Tooth sensitivity was daily recorded using a Likert scale varying from 1 (no sensitivity) to 5 (severe sensitivity). Analysis was carried out using non-parametric tests.Results Regarding the color change, at-home bleaching resulted in significant color improvement compared to in-office treatment for the parameters Δb* (p=0.003) and Δa* (p=0.014). Two weeks post-bleaching, the at-home treatment resulted in significant color improvement compared to in-office treatment for the parameters Δb* (p=0.037) and ΔE00 (p=0.033). No differences were observed in either ΔSGU parameters. Concerning sensitivity, patients treated with in-office bleaching reported more tooth sensitivity than the at-home group only on the first day after bleaching started, without significant differences in the other periods evaluated (p>0.05).Conclusions At-home and in-office bleaching, preceded by a desensitizing agent, were effective for vital teeth bleaching and 10% carbamide peroxide produced a higher whitening effect than 35% hydrogen peroxide in the short time evaluation. Tooth sensitivity rates were similar for the two techniques tested.

Processing and characterization of hemp nanofiber thermoset polymer composite

The objective of this study was to develop a natural fiber-based composite with fibers extracted through a simple technique called a steam explosion. These environment friendly materials having deterioration rate greater than that of the other polymer-based materials commonly used in manufacturing industries. During this study, the cellulose nanofibers were extracted from a hemp fiber with the help of steam explosion technique. To confirm its suitably for bio-based composites structure implementations, the characteristic features and morphological properties were meticulously studied. The chemical characterization of Hemp fiber material exhibited a rise in cellulose content from 64% to 95%, due to bleach, alkali and acid therapies. Scientific evidence confirms that non-cellulosic compounds extraction such as lignin and hemicellulose that occur in acid, steam explosion and bleaching treatment, as observed in chemical properties during pre and post chemical fiber therapy. Scanning electron microscopy studies indicates that a decrease in the fiber-diameter aspect ratio and the percentage yield of nano-fiber removed by such a procedure is found to be very high compared with other conventional approaches during steam explosion with acid treatment. X-ray diffraction analysis exhibited the crystallinity of fiber contained crystalline cellulose was increased due to performed procedure. The composite developed with the reinforcement of the steam explosion process demonstrate increased mechanical properties such as hardness, tensile strength and toughness of the material used (Epoxy LY 556 and Hardener HY 951). The cellulose fiber-reinforced composites were processed after obtaining the cellulose fiber from the steam explosion process. Mechanical properties such as harness, tensile strength and toughness were significantly improved.

Tensile Strength and Moisture Resistance Properties of Biocomposite Films Based on Polyvinyl Alcohol (PVA) with Cellulose as Reinforcement from Durian Peel Fibers

Polyvinyl Alcohol (PVA) based biocomposite film with cellulose was successfully fabricated by the solution casting method. The cellulose fibers were obtained by extraction of durian peel using alkalization and bleaching treatments. These treated cellulose fibers were used for the fabrication of PVA-based biocomposites. The durian peel cellulose fibers were varied by 2%, 4%, 6%, and 8% in the PVA matrix. Tensile test and moisture resistance of biocomposites were evaluated. The 6% addition of cellulose fibers in biocomposites increases the tensile strength up to 54% (37 MPa) than pure PVA film (24 MPa). Conversely, it reduces the elongation at break of the biocomposite film. Meanwhile, the moisture resistance properties of the biocomposites increased with the addition of cellulose fibers. The tensile strength and moisture resistance of biocomposites have been increased due to the homogeneous dispersion of the cellulose fibers and PVA matrix. These biocomposites able to reduce the environmental impacts by utilizing residual lignocellulosic biomass.

Reversal of deleterious effect of extracoronal in- office bleaching on shear bond strength of composite resin to bleached enamel: Effect of delayed restoration and different antioxidants application - in vitro study

Objective:The objective of this in - vitro study was to evaluate the effect of different antioxidants in reversal of of deleterious effect of bleaching on shear bond strength of composite resin to bleached enamel.Materials and methods: Seventy bovine incisors were used. The specimens were randomly divided into seven groups (10 specimens each) as follow: Group 1: no bleaching treatment and no antioxidant application. Group 2: bleaching only without antioxidant application and immediate composite resin application after bleaching. Group 3: bleaching only without antioxidant application and delayed composite application (after 2 weeks) of storage. Group 4: bleaching and application of 10% Alpha-tocopherol.Group 5: bleaching and application of 6% cranberry extract. Group 6:bleaching and application of 10% sodium ascorbate. Group 7: bleaching and application of 10% green tea. 40% hydrogen peroxide (Opalescence Xtra Boost 40%, Ultradent, South Jourdan, UT, USA) was used. Composite resin Tetric N -Ceram was used. The shear bond strength was measured using a universal testing machine. Results: one-way ANOVA test revealed significant differences in shear bond strength among the tested groups (p < 0.001). Bond strength significantly decreased after bleaching. There was no significant difference in shear bond strength reversed using10% Alpha-tocopherol, 10% sodium ascorbate and 10% green tea and delayed restoration. Whereas the difference was significant between group 5(6% cranberry extract) and other antioxidants groups. Conclusion: The results obtained from the use of antioxidants using (10% Alpha-tocopherol, 10% sodium ascorbate and 10% green tea extract) is approximately the same as the delayed restoration.

Clinical Evaluation of 6-Month Efficacy of 40% in-Office Whitening Treatment

Objective: To assess the 6-month efficacy of natural tooth color change in in-office bleaching treatment in terms of time by using a spectrophotometer. Material and Methods: A total of 20 participants were chairside treated with 40% hydrogen peroxide (HP), three applications each 20 minutes, in one appointment. Instrumental color measurement was performed on six anterior maxillary teeth before bleaching (baseline-t0), immediately after in-office bleaching and rehydration of the teeth (t1), 3 months (t2), and 6 months after bleaching treatment (t3). The spectrophotometer measured the tooth shades based on the CIE L*a*b* color notation system and Bleach index during the period of observation. CIE L*a*b* (ΔEab) color differences were calculated. Results: The color change at t1 was ΔEab = 3.2, at t2 was ΔEab = 1.8, at t3 was ΔEab = 1.2 and overall color change of in-office method was ΔEab = 3.6 (p<0.05). A significant effect for the mean CIEL*a*b* values was detected as within time b* values decreased significantly (p<0.05). Bleach index values significantly decreased during the time of observation, too (p<0.05). Conclusion: The in-office bleaching treatment using 40% hydrogen peroxide was effective, and the results showed a statistically significant decrease in color change during the period of 6-month observation.

Perception about tooth colour and appearance among patients seen in a tertiary hospital, South-West, Nigeria.

Introductionpatients´ satisfaction with their dental appearance and tooth colour is often influenced by certain factors which need to be addressed periodically among different populations.Methodsa self-administered questionnaire consisting of sociodemographic data, questions on patients´ satisfaction with tooth colour, perceived malalignment of teeth, non-aesthetic anterior tooth-coloured restoration and presence of tooth fracture were distributed. Data collected was analysed using Statistical Package for Social Sciences (IBM, SPSS version 20). Chi square was used to test the statistical differences at a significance of p> 0.05.Resultsa total of 410 patients (M=147, F=263) participated in the study. About 73% had tertiary education while 36.3% were within the modified ISCO-08 Group 2. The respondents that were satisfied with the general dental appearance and tooth shade were 66.3% and 63.5% respectively. More males (65.1%) than females (62.7%) were satisfied with tooth colour while more females (69.1%) were satisfied with dental appearance. The older age group were more satisfied with dental appearance and tooth colour. Awareness of tooth whitening (Over 80%) and the desire to undergo tooth whitening was more among the post-secondary individuals. More of dental patients (73.1%) than medical (59.2%) were satisfied with teeth appearance (p=0.003).Conclusionpatients are increasingly aware of their dental appearance/tooth colour and the need to improve it with tooth bleaching and/or orthodontic treatment. Female were more dissatisfied with their tooth colour but more satisfied with their dental appearance than the male. Older people were more satisfied with their dental appearance and tooth colour compared to younger age group.

Is prolonged bleaching more harmful to dental enamel than daily dietary and hygienic oral habits?

The ultrastructural and mechanical properties of enamel surface were evaluated after prolonged bleaching treatments with 10% carbamide peroxide in the presence or absence of orange juice (erosive challenge) and toothbrushing (abrasive challenge). In total, 145 incisor bovine teeth were used in this study. Twenty-five samples were prepared for the ultrastructural evaluations, and 120 samples were prepared for microhardness and roughness tests. These 120 samples were divided into eight experimental groups (n = 15): G1- artificial saliva; G2- abrasion; G3- erosion; G4- dental bleaching; G5- erosion + abrasion; G6- bleaching + abrasion; G7- bleaching + erosion; and G8- bleaching + erosion + abrasion. All groups were tested at T0 (before treatment), T1 (14 days), T2 (21 days), and T3 (28 days). Two-way analysis of variance for repeated measures and the post hoc Sidak tests (p ≤ 0.05) were used. The roughness evaluation demonstrated an increase in damage for all experimental groups with an increase in the time period. For microhardness, the groups exposed to artificial saliva (AS) and abrasive challenge did not show any differences at any time points, while the other groups showed a decrease in microhardness from T0 to T3. Ultrastructural evaluation showed different surface alterations in response to the treatments. Despite prolonged bleaching periods, the procedure caused lesser enamel surface alterations than exposure to orange juice alone or in combination with brushing.

Evaluating cinnamaldehyde as an antibacterial agent in a produce wash for leafy greens

Escherichia coli is a common foodborne pathogen in produce, especially leafy greens, which are often consumed raw. Post-harvest sanitizing is an essential step in mitigating the risk of foodborne illness associated with uncooked produce. We explore the potential antibacterial effects of cinnamaldehyde against E. coli when used as a produce wash for leafy greens. We hypothesized that treating leafy greens with cinnamaldehyde, a promising antibacterial agent, would yield an observable decrease in E. coli growth contamination, measured in colony-forming units (CFUs). In this study, we treated lettuce samples with various concentrations of cinnamaldehyde solution and compared the E. coli growth to water and bleach treatment controls. By analyzing either the leaf surface or the wash solution, we were able to detect the presence of E. coli. Lettuce treated with cinnamaldehyde in any concentration displayed significantly lower CFUs when compared to lettuce treated with chlorine bleach (p&amp;lt;0.00001). 0.5% and 1.0% cinnamaldehyde solutions were also more effective at inhibiting E. coli growth than 0.2% cinnamaldehyde (p=0.00387). Cinnamaldehyde had an effect on the survival rate of E. coli on lettuce that was equal to or greater than that of bleach. The concentration of cinnamaldehyde in the solution had a significant effect on the bacterial counts after washing; thus, we anticipate that cinnamaldehyde treatment may lead to a possible leafy green post-harvest wash solution.