Effect of Different Intraorifice Barriers and Bleaching Agents on the Fracture Resistance of Endodontically Treated Anterior Teeth.

INTRODUCTION: Intraorifice barriers (IOBs) are usually used before internal bleaching for coronal sealing and the prevention of cervical resorption. The aim of this study was to investigate the effect of different IOBs on the fracture resistance (FR) of endodontically treated anterior teeth bleached with various bleaching agents (BAs). METHODS: After performing root canal treatment for 72 extracted bovine upper incisors, the coronal 3 mm of gutta-percha was removed, and samples were classified into 3 based on the type of IOB: calcium-enriched mixture, mineral trioxide aggregate, and resin-modified glass ionomer. After applying IOBs, samples of each group were subdivided into 4 based on the BA: carbamide peroxide 45% (CP), hydrogen peroxide 35% (HP), sodium perborate (PB), and distilled water as the control. At the end of bleaching, the access cavities were restored with composite resin. The FR was measured with a universal testing machine at a crosshead speed of 5 mm/min. The data were analyzed using 2-way analysis of variance and least significant difference post hoc tests (P < .05). RESULTS: The effect of BAs on the FR was significant (P < .05); however, the effect of the IOB and the interactive effect of these variables were not significant (P > .05). The FR in the HP and PB groups was significantly different from the control (P < .05) but that of CP was not significantly different from the control (P > .05). CONCLUSIONS: Mineral trioxide aggregate and calcium-enriched mixture act similarly to resin-modified glass ionomer as an IOB. CP, unlike HP and PB, did not significantly decrease the FR.

Assessment of the efficacy and safety of a new complex skin cream in Asian women: A controlled clinical trial.

BACKGROUND: Medical products such as hydroquinone and tretinoin have been widely used to treat various types of skin hyperpigmentation. However, these products are limited in daily use given their adverse effects. Other alternative agents with fewer adverse side effects have been developed. However, single agents often do not produce satisfactory results. AIMS: To evaluate the efficacy and safety of a new brightening complex cream containing niacinamide, tranexamic acid, oxyresveratrol, glutathione disulfide, and linoleic acid. PATIENTS AND METHODS: A total of 26 Korean women seeking to lighten their skin were enrolled. The product was applied on the face two times per day for 12 weeks. Standardized photographs were taken at baseline, 4 weeks, 8 weeks, and 12 weeks. Efficacy was assessed using melanin index (MI), erythema index (EI), and chromatic aberration values (L*, a*, and b*). Improvement perceived by investigators and patients was measured as well. RESULTS: The L*-value was increased at 8 weeks (0.7±2.5, P<.05) and at 12 weeks (0.8±2.5, P<.05). The MI was significantly decreased at 8 weeks (-4.2±4.5, P<.05) and at 12 weeks (-3.8±4.8, P<.001). The EI was significantly improved at 12 weeks (-3.2±2.2, P<.001). More than 80% of patients were considered improved at 12 weeks based on the view of the investigators and patients. CONCLUSIONS: The new brightening complex cream was proved to be effective and safe in Asian women.

Women using bleach for home cleaning are at increased risk of non-allergic asthma.

BACKGROUND: Bleach is widely used for household cleaning. Although it is recognized that occupational use of bleach may have adverse respiratory health effects, it is unknown whether common domestic use of bleach may be a risk factor for asthma. AIM: To assess whether the domestic use of bleach for home cleaning is associated with asthma and other respiratory outcomes. METHODS: Questionnaire-based information on respiratory symptoms and cleaning habits and data from skin prick-tests, bronchial responsiveness challenge and white blood cells were analyzed in 607 women participating in the follow-up of the Epidemiological Study on the Genetics and Environment of Asthma (EGEA). Bleach use was evaluated in 3 categories (<1 day/week; 1-3 days/week; 4-7 days/week "frequent"). RESULTS: Overall, 37% of the women reported using bleach weekly. Women using bleach frequently (11%) were more likely to have current asthma as compared to non-users (adjusted Odds-Ratio (aOR) = 1.7; 95% Confidence Interval (95%CI) 1.0-3.0). Among women with asthma, frequent use of bleach was significantly associated with higher blood neutrophil cell counts. Bleach use was significantly associated with non-allergic asthma (aOR 3.3; 95%CI 1.5-7.1), and more particularly with non-allergic adult-onset asthma (aOR 4.9; 95%CI 2.0-11.6). Consistently, among women without allergic sensitization, significant positive associations were found between use of bleach and bronchial hyperresponsiveness, asthma like-symptoms and chronic cough. No association was observed for allergic asthma. CONCLUSIONS: Frequent use of bleach for home-cleaning is associated with non-allergic adult-onset asthma, elevated neutrophil counts and lower-airway symptoms in women.

The Damage Pattern to the Gastrointestinal Tract Depends on the Nature of the Ingested Caustic Agent.

BACKGROUND: The mechanisms of damage to the gastrointestinal tract after caustic ingestion are conditioned by the nature of the ingested agent. Whether the nature of the ingested agent has a direct influence on patient outcomes is unknown. METHODS: From January 2013 to April 2015, 144 patients underwent emergency management for caustic injuries at the Saint Louis Hospital in Paris. There were 51 men (51 %) and the median age was 44 years [39, 48]. The ingested agents were soda-based strong alkali in 85 patients (59 %), strong acids in 36 patients (25 %), and bleach in 23 patients (16 %). Emergency and long-term outcomes were compared according to the nature of the ingested agent. RESULTS: Four patients died (3 %) and 40 patients (28 %) experienced complications. After bleach ingestion, emergency morbidity and mortality were nil, no patient required esophageal reconstruction, and functional outcome was successful in all patients. Acids were more likely to induce transmural gastric (31 vs. 13 %, p =0.042) and duodenal (9 vs. 0 %, p = 0.04) necrosis than strong alkalis, but rates of transmural esophageal necrosis were similar (14 vs. 12 %, p = 0.98). No significant differences were recorded between emergency mortality (9 vs. 1 %, p = 0.15), morbidity (33 vs. 33 %, p = 0.92), the need for esophageal reconstruction (25 vs. 20 %, p = 0.88), and functional success rates (76 vs. 84 %, p = 0.31) after acid and alkali ingestion, respectively. CONCLUSION: Bleach causes mild gastrointestinal injuries, while the ingestion of strong acids and alkalis may result in severe complications and death. Acids cause more severe damage to the stomach but similar damage to the esophagus when compared to alkalis.

Chemical processing and shampooing impact cortisol measured in human hair.

PURPOSE: The assessment of cortisol in hair has gained popularity as a means to measure retrospective hypothalamic-pituitary-adrenal activity in a number of species; however, cortisol levels from human hair subjected to typical chemicals for cosmetic or hygienic purposes may be altered by the chemicals used. The purposed of this study was to determine if exposure of hair to chemical processing or shampooing impacts cortisol values. METHODS: Human hair not exposed to prior chemical processing was cut from the posterior vertex region of the head of 106 human subjects as close to the scalp as possible. The hair sample was divided into 4-6 full-length clusters depending on quantity of hair available. Each hair sample was processed for baseline (native) cortisol and remaining clusters were exposed to five standard chemical hair treatments (Experiment 1) or were shampooed 15 or 30 times (Experiment 2). Hair was ground and cortisol levels were determined by enzyme immunoassay (EIA). Comparisons were made between native hair and processed hair using paired t-tests and Pearson correlation. RESULTS: Hair cortisol as assessed by EIA was significantly altered by chemical processing but in somewhat different ways. Exposure to bleach (harshest exposure), demi-perm (least exposure) or 15-30 shampoos resulted in a significant decrease in cortisol level while exposure to varying percentages of peroxides increased cortisol measured. There were no differences in cortisol levels associated with sex, age or tobacco use in the native hair for this particular group. CONCLUSION: Chemical processing and frequent shampooing affect cortisol levels measured in hair. Chemically processed or excessively shampooed hair should be avoided when recruiting subjects for hair cortisol studies.

The practice of skin-bleaching for a cosmetic purpose in immigrant communities.

BACKGROUND: Using skin-lightening compounds for a cosmetic purpose that are normally restricted to medical use or forbidden has become a world-wide practice. Complications are numerous. Immigrant communities often import their practice from their original country. METHODS: A review of the literature on the subject of complications of cosmetic skin-bleaching, with special focus on data concerning immigrants originating from highly endemic countries, was conducted. RESULTS: Complications of cosmetic skin-bleaching are common, involving mainly the skin although some general complications are also reported with a growing incidence. CONCLUSION: The high frequency of this practice, added to the frequency of various complications, suggests it might be considered as a genuine public health problem currently.

Exogenous ochronosis in a Chinese patient: use of dermoscopy aids early diagnosis and selection of biopsy site.

The diagnosis of exogenous ochronosis is often challenging and requires a high index of suspicion. Herein, we report a case of exogenous ochronosis in a Chinese patient. The condition was caused by the use of bleaching agents, including creams containing hydroquinone. We demonstrate the use of dermoscopy as an invaluable tool for the early recognition of the condition, as well as in the selection of an appropriate site for a skin biopsy.

Effect of bleaching agents and soft drink on titanium surface topography.

The effects of carbamide peroxide, hydrogen peroxide and cola soft drink on the topographic modifications of commercially-pure titanium (CP-Ti) and Ti-6Al-4V were investigated. Ti discs were divided into 18 groups (n = 4) based on the solution treatment and Ti type. Specimens were immersed in 3 mL of each solution for 4 h per day (for the remaining 20 h, discs were left dry or immersed in artificial saliva) for 15 days. For control, specimens were immersed in only artificial saliva. Ti surfaces were examined using scanning electron (SEM) and atomic force (AFM) microscopes and their surface roughness (in µm) and surface chemical modifications were investigated. Data were analyzed by ANOVA and Tukey's test (α = 0.05). Groups immersed in 35% hydrogen peroxide showed the highest roughness (Ra) (171.65 ± 4.04 for CP-Ti and 145.91 ± 14.71 for Ti-6Al-4V) (p < 0.05), followed by groups treated with carbamide peroxide 16% (110.91 ± 0.8 for CP-Ti and 49.28 ± 0.36 for Ti-6Al-4V) and 35% (65.67 ± 1.6 for CP-Ti and 53.87 ± 1.98 for Ti-6Al-4V); treatment with artificial saliva did not affect the results. These values were statistically superior to those observed prior to the treatment and to those of the control group (31.0 ± 0.99 for CP-Ti and 29.95 ± 0.58 for Ti-6Al-4V). Cola soft drink did not alter the surface roughness of either Ti type (p > 0.05). SEM and AFM revealed dramatic changes in the specimens surfaces immersed in the 35% hydrogen peroxide, mainly for CP-Ti. No detectable chemical modifications on the Ti surface were observed. Bleaching agents promoted significant changes in Ti topography, which could affect the longevity of implants treatments.

Genotoxic effect of two bleaching agents on oral mucosa.

AIM: To analyze the genotoxic effect of two hydrogen peroxide-containing bleaching products on oral mucosal cells. MATERIALS AND METHODS: The research was conducted on 22 individuals divided into two groups. Group 1 used ZOOM2 and group 2 the Opalescence BOOST bleaching agent. Specimens of the gingival and the upper lip mucosa were obtained before, immediately after, and 72 h after the bleaching procedure and were analyzed using a micronucleus test. RESULTS: Seventy-two hours after bleaching treatment with BOOST, samples collected from the oral mucosa exhibited a statistically significant increase of all genotoxicity markers, with large effect sizes (Cohen's d>0.8) observed in the total number of micronuclei (MN), number of cells with 3+ MN, karyolysis and bi-nuclear cells. ZOOM2 treatment showed a significant increase, with medium-to-large effect sizes, in the number of cells with 1 MN, karyolysis, nuclear buds and bi-nuclear cells. CONCLUSION: Both preparations demonstrated potential genotoxic effects.

Assessment of the release of mercury from silver amalgam alloys exposed to different 10% carbamide peroxide bleaching agents.

This in vitro study assessed the amount of mercury (Hg) released from a silver amalgam alloy following the application of different 10% carbamide peroxide bleaching agents. A total of 30 specimens (2 mm thick x 4 mm in diameter) were stored in deionized water at 37°C for 7 days. Next, the control group (n = 10) remained in the deionized water for 15 days, while the remaining samples were exposed to 1 of 2 bleaching agents (n = 10) for 8 hours daily (total exposure = 120 hours); for the remaining 16 hours, specimens in the test groups were stored in deionized water at 37°C under relative humidity. After this period, the quantity of Hg in the deionized water was assessed (using atomic absorption spectrophotometry) and compared to the amount of Hg at baseline. The results indicate that exposing amalgam alloys to bleaching agents released greater amounts of Hg compared to exposing samples to deionized [corrected] water.

Effects of bleaching agents and adhesive systems in dental pulp: a literature review

The dental pulp may be exposed to several irritants that are potentially noxious to the health and functions of this tissue. Each type of irritant or injury has different effects on the pulp, which are generally characterized by acute inflammation, chronic inflammation or necrosis. Common examples of irritants are dental caries, cavity preparation procedures, traumatic injuries, and chemical substances like bleaching agents and adhesive systems. The present study aimed to review the current knowledge about the effect of bleaching agents and adhesive systems in the human dental pulp. The review covered literature from 2004 to 2009, and only relevant manuscripts were included. Hand search of the references completed the review. Based on literature review, it may be concluded that all dental procedures associated with bleaching agents or adhesive systems involve risks to cause pulp damage. However, these risks can be minimized if the causal factors were known and avoided.

Topical 5% tranexamic acid for the treatment of melasma in Asians: a double-blind randomized controlled clinical trial.

BACKGROUND: Topical tranexamic acid has been claimed to lighten melasma without serious adverse effects. However, controlled studies assessing the efficacy and safety of topical tranexamic acid (TA) for the treatment of melasma is limited. OBJECTIVE: To assess in a double blind, randomized, prospective study, the efficacy of topical 5% tranexamic acid versus vehicle for treatment of melasma. METHODS: Twenty-three women with bilateral epidermal melasma enrolled in a split-face trial lasting 12 weeks. Patients blindly applied topical 5% tranexamic acid and its vehicle, to the designated sides of the face twice daily in addition to the assigned sunscreen each morning. Pigmentation and erythema were measured objectively using a mexameter and Melasma Area and Severity Index (MASI), in addition to physician and patient global assessments. RESULTS: Twenty-one patients completed the study. Eighteen out of twenty-three patients (78.2%) showed decrease in the melanin index on either or both sides of the face by the end of 12 weeks compared to baseline. The MASI scores were also significantly reduced on both tested sides. However, lightening of pigmentation induced by TA gel was neither superior nor different (p > 0.05) compared to its vehicle although erythema was significant on the TA-applied site (p < 0.05). CONCLUSIONS: Although lightening of pigmentation was obtained, the results were not significant between the two regimens. However, topical TA produced erythema.