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pH Meter (ph + meter)
Selected AbstractsInfluence of dentin on pH of 2% chlorhexidine gel and calcium hydroxide alone or in combinationDENTAL TRAUMATOLOGY, Issue 3 2010Laila Gonzales Freire Most of the times, these objectives are not achieved solely by chemomechanical preparation, and intracanal dressing may be necessary. In these cases, calcium hydroxide is used as a root canal dressing due to its well-known and recognized antimicrobial activity. Chlorhexidine has a wide spectrum of antimicrobial activity and its association with calcium hydroxide has been recommended in an attempt to amplify antimicrobial effects of calcium hydroxide. It is also known that dentin exerts a buffering effect under wide pH variations, and may be responsible for decreasing the antimicrobial activity of drugs inside the root canal. The objectives of this study were to assess the pH of 2% chlorhexidine gel and calcium hydroxide alone or in combination, as well as the influence of dentin on the pH of these compounds. Dentin powder was obtained from bovine teeth and added as 1.8% to the volume of the medications. All substances were individually stored in plastic flasks, in triplicate. A pH meter was used at five different moments to assess pH in viscous medium: immediately after preparation and after 24 h, and 7, 14, and 21 days. Results were analyzed by paired Student's t -test. Statistically significant differences were observed in the 2% chlorhexidine gel group alone or associated with calcium hydroxide and added of dentin powder (P < 0.05). Mean pH values indicated the influence of dentin powder because of a significant increase in pH. Calcium hydroxide with propylene glycol as the vehicle always showed high pH, demonstrating that this compound was not affected by the presence of dentin. [source] Development of flame retardancy properties of new halogen-free phosphorous doped SiO2 thin films on fabricsJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2007Aysun Cireli Abstract In this study, flame retardancy properties of fabrics treated with phosphorous (P) doped and undoped SiO2 thin films were developed by sol,gel technique. As to this aim, P-doped and undoped SiO2 film were coated on cotton fabric from the solutions prepared from P, Si-based precursors, solvent, and chelating agent at low temperature in air using sol,gel technique. To determine solution characteristics, which affect thin film structure, turbidity, pH values, and rheological properties of the prepared solutions were measured using a turbidimeter, a pH meter, and a rheometer machines before coating process. The thermal, structural, and microstructural characterization of the coating were done using differential thermal analysis/thermograviometry, fourier transform infrared spectroscopy, X-ray diffractometry, and scanning electron microscopy. In addition, tensile strength, wash fastness, flame retandancy, and lightness properties of the coated fabrics were determined. To compensate the slight loss of tensile strength of samples, which occurred at the treated fabrics with P-doped Si-based solutions, the cotton fabrics were coated with polyurethane films during second step. In conclusion, the flame retardant cotton fabric with durability of washing as halogen-free without requiring after treatment with formaldehyde was fabricated using sol,gel processing for the first time. Moreover the cotton fabrics, which were treated with P-doped Si-based solutions and then coated with polyurethane at second step, still has got nonflammable property. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007 [source] Management of night-time urinary incontinence in residential settings for older people: an investigation into the effects of different pad changing regimes on skin healthJOURNAL OF CLINICAL NURSING, Issue 3 2003Mandy Fader BSc Summary ,,Absorbent pads are the main method of managing urinary incontinence in residential settings for older people. ,,Improvements in technology have resulted in highly absorbent products which may be worn all night, but the effects of prolonged pad wearing on aged skin are unknown. ,,The aim of this study was to examine the effects of two different pad changing regimes on skin health. ,,A cross-over design was used. ,,Subjects from residential settings were randomly allocated to one of two pad changing regimes: a frequent pad changing regime or a less frequent pad changing regime. Each regime lasted 4 weeks and was followed by the alternative regime. ,,Skin measurements were taken twice during each regime using (i) the Diastron Erythema meter, (ii) a visual grading scale, (iii) the Servomed evaporimeter, and (iv) a pH meter. The primary outcome variable was the Diastron Erythema meter index. ,,Eighty-one subjects completed the study. ,,No significant differences were found in the severity of erythema, or skin pH, between regimes. Measurements of trans-epidermal water loss were significantly higher in the less frequent pad changing regime indicating that skin was ,wetter' (P = 0.01; 95% CI: 2.89,21.39). ,,Five subjects developed grade 2 pressure ulcers (abrasions) during the less frequent pad changing regime, but none in the frequent pad changing regime; this result was not significant (P = 0.1; 95% CI: 0,1.09). ,,No evidence was found that a less frequent pad changing regime has an effect on skin erythema or pH. ,,There is evidence that skin is wetter which may make it more vulnerable to friction and abrasion. ,,The statistically non-significant finding of greater incidence of grade 2 pressure ulcers is a cause for concern and merits further investigation because of the clinical significance of loss of skin integrity. [source] The distribution of oral mucosal pH values in healthy saliva secretorsORAL DISEASES, Issue 4 2006DJ Aframian Objectives:, To establish the normal range of oral mucosal pH and to correlate these measurements to salivary flow rate in healthy individuals according to age and gender. Subjects and methods:, Measurements of pH levels using a flat pH meter and salivary secretion rates were established in eight mucosal sites from a total of 50 healthy individuals. Results:, The mean pH (±s.d.) of all sites was 6.78 ± 0.04 with significant differences between mean pH values in the palate (7.34 ± 0.38), the floor of the mouth (6.5 ± 0.3), the buccal mucosa (6.28 ± 0.36) and the tongue (6.8 ± 0.26). A significant correlation was found between age and pH at palatal and tongue sites but no gender effects were noted. Conclusions:, This method is easy and relatively quick to manipulate, and may offer many diagnostic possibilities for oral related diseases and disorders such as oral malodour, mouth breathing, dysgeusia, acidic diet consumption and gastrointestinal disorders affecting the mouth. [source] Relationship between quantitative assessments of salivary buffering capacity and ion activity product for hydroxyapatite in relation to cariogenic potentialAUSTRALIAN DENTAL JOURNAL, Issue 2 2008H Aiuchi Abstract Background:, The ion activity product for hydroxyapatite (IpHA) is a comprehensive parameter reflecting pH, calcium and phosphate ion concentration in saliva which govern the degree of saturation with respect to the dissolving tooth mineral. The aim of this study was to evaluate the relationship between quantitative assessments of salivary buffering capacity and IpHA in relation to cariogenic potential. Methods:, Stimulated whole saliva was collected from 33 patients, and the initial pH of samples was measured using a hand-held pH meter. Then samples were titrated with 0.1 N HCl to evaluate buffering capacities and divided into three groups (high, medium and low). After measuring concentrations of calcium and phosphate ions in the samples, IpHA was calculated using the values of the ion concentrations and pH. Differences in the mean pH values, the concentrations of calcium, phosphate ions and log[IpHA] among three groups were analysed using the Kruskal Wallis and the Mann-Whitney non-parametric test, p < 0.05. Results:, After HCl 50 ,L titration, there were statistical differences of the mean pH and IpHA among each buffering capacity group. Moreover, after 50 ,L HCl titration, there was an excellent correlation between the buffer capacity and log[IpHA]. Conclusions:, The pH change for saliva after HCl titration has a significant influence on the rate of IpHA. [source] The pH change after HCl titration into resting and stimulated saliva for a buffering capacity testAUSTRALIAN DENTAL JOURNAL, Issue 2 2006M. Moritsuka Abstract Background: Saliva collection can provide clinical information about individual patients. However, a correlation between ranking buffering capacity using resting and stimulated saliva is still unknown. The aim of this study was to evaluate the pH change after HCl titration into resting and stimulated saliva for a salivary buffering capacity test. Methods: Resting and stimulated saliva (by chewing paraffin wax) were collected from 80 patients. After the pH of both saliva samples was measured using a hand-held pH meter, the saliva samples were titrated with 0.1N HCl to evaluate the buffering capacity. Correlations of ranking buffering capacity (high, medium, low) between stimulated saliva and resting saliva with 30,L HCl titration and between stimulated saliva and resting saliva with 40,L HCl titration were statistically analysed by Spearman Rank Correlation Test (p < 0.05). Results: At 50,L HCl titration, stimulated saliva buffering capacities were ranked into high (above pH 5.5), medium (pH from 5.5 to 4.5) and low (below pH 4.5). At 30,40,L HCl titration, the resting saliva buffering capacities were ranked into the same categories. Spearman Rank Correlation indicated significant positive coefficients for the stimulated saliva and resting saliva buffering capacity at 30,L titration and the stimulated saliva and resting saliva at 40,L titration. Conclusion: Stimulated saliva is more resistant to variation in pH change during HCl titration than resting saliva. Stimulated saliva sampling is a good method to determine buffering capacity during a comprehensive oral health assessment. [source] Facilitating student understanding of buffering by an integration of mathematics and chemical concepts,BIOCHEMISTRY AND MOLECULAR BIOLOGY EDUCATION, Issue 2 2004Robert Curtright Abstract We describe a simple undergraduate exercise involving the titration of a weak acid by a strong base using a pH meter and a micropipette. Students then use their data and carry out graphical analyses with a spreadsheet. The analyses involve using mathematical concepts such as first-derivative and semi-log plots and provide an opportunity for collaboration between biochemistry and mathematics instructors. By focusing on titration data, rather than the titration process, and using a variety of graphical transformations, we believe that students achieve a deeper understanding of the concept of buffering. [source] | ||||||||||