1,720,998 research outputs found
FTIR, Raman and SEM analysis of enamel and dentin after the application of stannous flouride
No full textAnalysis of enamel and dentin performed by Raman, SEM and FTI
FTIR, Raman and SEM analysis of enamel and dentin after the application of stannous flouride
No full textTreatment of dentin sensitivity with stannous fluoride gel. Electron microscopic study and evaluation of dentin permeability
No full textDentine hypersensitivity still represent a major clinical problem only partially solved. The presence of exposed opened dentinal tubules has been demonstrated increase the dentine permeability and it is the responsible for pain and sensitivity. Stannous fluoride solution has been recently proposed to reduce dentine hypersensitivity. The aim of the present study was to evaluate the dentinal permeability of a new stannous fluoride gel proposed for the therapy of dentine hypersensitivity. Human extracted teeth have been used and mounted and connected with a hydraulic pressure apparatus working at 1 psi (70 cm of water pressure). It was calculated the permeability of untreated smear layer, treated smear layer (after gel application) and after acidic treatment. It was observed that gel treatment was able to reduce dentine permeability. Scanning electron microscopy demonstrated the presence of a homogeneous smear layer after treatment with gel. This in vitro study confirms that stannous fluoride treatment has the capacity to modify dentine permeability of sensitive dentine
Hydration kinetics of cements by Time-Domain Nuclear Magnetic Resonance: application to Portland-cement-derived endodontic pastes
No full textTime-Domain Nuclear Magnetic Resonance (TD-NMR) of 1H nuclei is used to monitor the maturation up to 30 days of three different endodontic cement pastes. The “Solid–liquid” separation of the NMR signals and quasi-continuous distributions of relaxation times allow one to follow the formation of chemical compounds and the build-up of the nano- and subnano-structured C–S–H gel. 1H populations, distinguished by their different mobilities, can be identified and assigned to water confined within the pores of the C–S–H gel, to crystallization water and Portlandite, and to hydroxyl groups. Changes of the TD-NMR parameters during hydration are in agreement with the expected effects of the different additives, which, as it is known, can substantially modify the rate of reactions and the properties of cementitious pastes. Endodontic cements are suitable systems to check the ability of this non-destructive technique to give insight into the complex hydration process of real cement pastes
A preliminary study of human pineal gland concretions: structural and chemical analysis.
No full textAcervuli and fragments of pineal gland obtained from 33 subjects of both sexes and age ranging from 1 to 87 years, (30 autopsy and 3 biopsy specimens) were analyzed by light microscopy, transmission and scanning electron microscopy, X-ray diffraction and X-ray energy dispersive microanalysis. It was found that primary mineralization occurs in an organic matrix formed by pinealocytes and that hydroxyapatite also takes place in mineral deposition. From our analysis, the formation of acervuli appears to be age and sex independent and can be possibly related to the secretory activity of the gland
Dentin Permeability After Toothbrushing with Two Different Toothpastes
No full textThe present study aims to assess the morphology of enamel and dentin after treatments with various toothpastes in powder or paste form recently proposed for home use. Dentin permeability was calculated as hydraulic conductance (Lp). We also assessed the effect of manual brushing for a limited period on dentin morphology. Scanning electron microscopy (SEM) was made to evaluate the morphology of dentin after toothpaste treatment and application. Material Method. We uused teeth (third molars) extracted for orthodontic reasons from patients with a mean age of 32.5 years. Dentin permeability measurement. Each dentin disc was connect to a hydraulic system with a pressure of 30cm/H2O. After preparation, each sample was connected to hydraulic pressure apparatus to evaluate the permeability of dentin with the smear layer produced during the sectioning step. After 5 minutes, dentin was etched with 37% phosphoric acid gel for 2 minutes, washed and gently dried with cotton to measure the permeability after smear layer removal. The next phase was to examine dentin before and after treatments with toothpaste and brushing with scanning electron microscope (SEM).
Results. No particular differences between the three products were seen (ename)l; however, the smear layer appeared modified and removed to a greater extent with Merfluan dental salts. Overall, the smear layer (on both enamel and dentin) was extremely thin, since producing and preparing the sample involved only light, weak movements with abrasive instruments.
Conclusion. This study shows that all the toothpastes tested interact with a substratum, in this case the dentinal smear layer. The enamel smear layer, however, was more compact and less easily modified. Nonetheless, it should borne in mind that a single application of toothpaste and one brushing, however energetic, are unlikely to lead to modifications of a hard surface such a ename
Treatment of dentin hypersensitivity with stannous fluoride: a scanning elctron microscopy study and dentin permeability evaluations
No full textDentin hypersensitivity in caused by open dentinal tubules which increase permeability. In remains a serious clinical problem, since attempts to deal with in have only been partly successful. One recent form of treatments is stannous fluoride gel (GELKAM, Colgate).
The present study is intended to evaluate the electron microscope picture (SEM) of morphology of the dentin surface with and without smear layer (removed with acid solution) and the degree of dentin permeability. The latter in considered the main indicator directly correlated to the degree of dentin sensitivity and to morphology. Dentin permeability was studied with a hydraulic apparatus working at 1.0 psi pressure, equal approximately 70 cm of water. Stannous fluoride gel reduced dentin permeability and changed smear layer morphology, with the formation of a thick, compact layer. This study confirms in vitro the ability of Gel Kam to reduce dentin sensitivity in vivo
Dentine Permeability and Dentine Morphology after Treatment with Sanguinaria Canadensis and Chlorexidine
No full textToothpastes, mouthwashes, liners, that remove smear layer and increase the functional diameter of dentinal tubules may be responsible for hypersensitivity and pain. The aim of this study to evaluate in vitro the effect on dentin permeability of two mouthwashes proposed for periodontal therapy: Periogard with Sanguinaria Canadensis 0.03% (Colgate, USA) and Periogard with Chlorexidine 0.2% (Colgate, USA). Twenty-four occlusally sectioned crown segments from human extracted third molars were divided into four groups and connected to an in vitro hydraulic apparatus as described by Pashely et al. (1978). All groups were etched with 37% phosphoric acid gel (3M, USA) to remove the smear layer and to calculate the maximum permeability. In two groups, smear layer was recreated using #400 3M sandpaper disks. Finally, the undiluted mouthwashes were applied and brushed on the dentin for 3 minutes with a toothbrush (Colgate, USA). Each sample was then washed with water and dentin permeability was evaluated. Four measurements of permeability (expressed as hydraulic conductance in ml/min per cm H2O) were made for each sample the averaged. ANOVA tests and Paired Student's test were used where appropriate. SEM analysis was made on the same samples
Dentine Permeability and Dentine Morphology after Treatment with Sanguinaria Canadensis and Chlorexidine
No full textToothpastes, mouthwashes, liners, that remove smear layer and increase the functional diameter of dentinal tubules may be responsible for hypersensitivity and pain. The aim of this study to evaluate in vitro the effect on dentin permeability of two mouthwashes proposed for periodontal therapy: Periogard with Sanguinaria Canadensis 0.03% (Colgate, USA) and Periogard with Chlorexidine 0.2% (Colgate, USA). Twenty-four occlusally sectioned crown segments from human extracted third molars were divided into four groups and connected to an in vitro hydraulic apparatus as described by Pashely et al. (1978). All groups were etched with 37% phosphoric acid gel (3M, USA) to remove the smear layer and to calculate the maximum permeability. In two groups, smear layer was recreated using #400 3M sandpaper disks. Finally, the undiluted mouthwashes were applied and brushed on the dentin for 3 minutes with a toothbrush (Colgate, USA). Each sample was then washed with water and dentin permeability was evaluated. Four measurements of permeability (expressed as hydraulic conductance in ml/min per cm H2O) were made for each sample the averaged. ANOVA tests and Paired Student's test were used where appropriate. SEM analysis was made on the same samples
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