Αρχειοθήκη ιστολογίου

Αλέξανδρος Γ. Σφακιανάκης
ΩτοΡινοΛαρυγγολόγος
Αναπαύσεως 5
Άγιος Νικόλαος Κρήτη 72100
2841026182
6032607174

Τρίτη 10 Απριλίου 2018

Determining chewing efficiency using a solid test food and considering all phases of mastication

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Publication date: Available online 10 April 2018
Source:Archives of Oral Biology
Author(s): Ting Liu, Xinmiao Wang, Jianshe Chen, Hilbert W. van der Glas
ObjectivesFollowing chewing a solid food, the median particle size, X50, is determined after N chewing cycles, by curve-fitting of the particle size distribution. Reduction of X50 with N is traditionally followed from N ≥ 15-20 cycles when using the artificial test food Optosil®, because of initially unreliable values of X50. The aims of the study were (i) to enable testing at small N-values by using initial particles of appropriate size, shape and amount, and (ii) to compare measures of chewing ability, i.e. chewing efficiency (N needed to halve the initial particle size, N(1/2-Xo)) and chewing performance (X50 at a particular N-value, X50,N).Design8 subjects with a natural dentition chewed 4 types of samples of Optosil particles: (1) 8 cubes of 8 mm, border size relative to bin size (traditional test), (2) 9 half-cubes of 9.6 mm, mid-size; similar sample volume, (3) 4 half-cubes of 9.6 mm, and 2 half-cubes of 9.6 mm; reduced particle number and sample volume. All samples were tested with 4 N-values. Curve-fitting with a 2nd order polynomial function yielded log(X50)-log(N) relationships, after which N(1/2-Xo) and X50,N were obtained.ConclusionsReliable X50-values are obtained for all N-values when using half-cubes with a mid-size relative to bin sizes. By using 2 or 4 half-cubes, determination of N(1/2-Xo) or X50,N needs less chewing cycles than traditionally. Chewing efficiency is preferable over chewing performance because of a comparison of inter-subject chewing ability at the same stage of food comminution and constant intra-subject and inter-subject ratios between and within samples respectively.



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Long-term evaluation of the stability of dentin matrix following treatments with aqueous solutions of titanium tetrafluoride at different concentrations

S00039969.gif

Publication date: Available online 10 April 2018
Source:Archives of Oral Biology
Author(s): E.C. Bridi, A.A. Leme-Kraus, B. Aydin, R.T. Basting, A.K. Bedran-Russo
ObjectiveThe purpose of this study was to investigate the effects of aqueous solutions of different concentrations of titanium tetrafluoride (TiF4) on dentin matrix stability up to six months.DesignDentin specimens prepared from fifteen nonerupted molars were demineralized and randomly distributed into groups: 2.5% TiF4, 4% TiF4, 1000 ppm NaF, and control (distilled water). The modulus of elasticity (ME) and dry masses of the dentin matrix were determined at baseline, and up to 6 months following treatment. Collagen solubilization was estimated by hydroxyproline (HYP) quantification in the simulated body fluid used to store the dentin specimens.ResultsThe 2.5% TiF4 group presented higher ME immediately after treatment, and at 3 and 6 months storage, whereas 4% TiF4 showed higher means at 3 and 6 months (p < 0.001). No significant differences were observed among the groups over time (p = 0.9325). However, the 2.5% TiF4 group showed significantly higher ME than the control group, immediately after treatment. All the groups presented significantly higher mass change immediately, compared with 3 and 6 months (p < 0.0001). Except for the 4% TiF4 group, HYP release was higher in the first quarter (p = 0.0152), when no significant differences were found among the groups. In the second quarter, the means were significantly higher in the 2.5% TiF4 and 4% TiF4 groups. The group treated with 2.5% TiF4 had a statistically higher HYP release than the control group.ConclusionAn aqueous solution of 2.5% TiF4 increases the immediate stiffness values, but does not stabilize the collagenous dentin matrix.



https://ift.tt/2IIH2Jb

Determining chewing efficiency using a solid test food and considering all phases of mastication

S00039969.gif

Publication date: Available online 10 April 2018
Source:Archives of Oral Biology
Author(s): Ting Liu, Xinmiao Wang, Jianshe Chen, Hilbert W. van der Glas
ObjectivesFollowing chewing a solid food, the median particle size, X50, is determined after N chewing cycles, by curve-fitting of the particle size distribution. Reduction of X50 with N is traditionally followed from N ≥ 15-20 cycles when using the artificial test food Optosil®, because of initially unreliable values of X50. The aims of the study were (i) to enable testing at small N-values by using initial particles of appropriate size, shape and amount, and (ii) to compare measures of chewing ability, i.e. chewing efficiency (N needed to halve the initial particle size, N(1/2-Xo)) and chewing performance (X50 at a particular N-value, X50,N).Design8 subjects with a natural dentition chewed 4 types of samples of Optosil particles: (1) 8 cubes of 8 mm, border size relative to bin size (traditional test), (2) 9 half-cubes of 9.6 mm, mid-size; similar sample volume, (3) 4 half-cubes of 9.6 mm, and 2 half-cubes of 9.6 mm; reduced particle number and sample volume. All samples were tested with 4 N-values. Curve-fitting with a 2nd order polynomial function yielded log(X50)-log(N) relationships, after which N(1/2-Xo) and X50,N were obtained.ConclusionsReliable X50-values are obtained for all N-values when using half-cubes with a mid-size relative to bin sizes. By using 2 or 4 half-cubes, determination of N(1/2-Xo) or X50,N needs less chewing cycles than traditionally. Chewing efficiency is preferable over chewing performance because of a comparison of inter-subject chewing ability at the same stage of food comminution and constant intra-subject and inter-subject ratios between and within samples respectively.



https://ift.tt/2JwR94K

Long-term evaluation of the stability of dentin matrix following treatments with aqueous solutions of titanium tetrafluoride at different concentrations

S00039969.gif

Publication date: Available online 10 April 2018
Source:Archives of Oral Biology
Author(s): E.C. Bridi, A.A. Leme-Kraus, B. Aydin, R.T. Basting, A.K. Bedran-Russo
ObjectiveThe purpose of this study was to investigate the effects of aqueous solutions of different concentrations of titanium tetrafluoride (TiF4) on dentin matrix stability up to six months.DesignDentin specimens prepared from fifteen nonerupted molars were demineralized and randomly distributed into groups: 2.5% TiF4, 4% TiF4, 1000 ppm NaF, and control (distilled water). The modulus of elasticity (ME) and dry masses of the dentin matrix were determined at baseline, and up to 6 months following treatment. Collagen solubilization was estimated by hydroxyproline (HYP) quantification in the simulated body fluid used to store the dentin specimens.ResultsThe 2.5% TiF4 group presented higher ME immediately after treatment, and at 3 and 6 months storage, whereas 4% TiF4 showed higher means at 3 and 6 months (p < 0.001). No significant differences were observed among the groups over time (p = 0.9325). However, the 2.5% TiF4 group showed significantly higher ME than the control group, immediately after treatment. All the groups presented significantly higher mass change immediately, compared with 3 and 6 months (p < 0.0001). Except for the 4% TiF4 group, HYP release was higher in the first quarter (p = 0.0152), when no significant differences were found among the groups. In the second quarter, the means were significantly higher in the 2.5% TiF4 and 4% TiF4 groups. The group treated with 2.5% TiF4 had a statistically higher HYP release than the control group.ConclusionAn aqueous solution of 2.5% TiF4 increases the immediate stiffness values, but does not stabilize the collagenous dentin matrix.



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A simple management option for chronically impacted sharp tracheobronchial foreign bodies in children

Distally impacted chronic tracheobronchial sharp foreign bodies in children are a management challenge that presents with clinical subtlety and extreme variability. The use of image guided techniques, imaginat...

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Hemorrhagic stroke after Epley maneuver: a case report

This is the first case to our knowledge of a serious adverse event following the Epley maneuver, which is the treatment of choice for benign paroxysmal positional vertigo (BPPV), the most common vestibular dis...

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An update on molecular cat allergens: Fel d 1 and what else? Chapter 1: Fel d 1, the major cat allergen

Cats are the major source of indoor inhalant allergens after house dust mites. The global incidence of cat allergies is rising sharply, posing a major public health problem. Ten cat allergens have been identif...

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