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1.
Biomed Res Int ; 2019: 9101642, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31781651

RESUMO

Objective: This in vitro study is aimed at investigating the caries preventive effectiveness of 445 nm diode laser in combination with topical fluoridation. Materials and methods: A total of 30 caries-free bovine teeth were used in this study. Eighteen teeth were covered with nail varnish except four windows on the labial surface. The windows were assigned to no treatment/control (C), laser (L) (0.3 W, 60 s, and 90 J/cm2), fluoride (F), and fluoride followed by laser (FL) treatment groups. Artificial caries lesions were created, and the teeth were sectioned and investigated under polarized light microscopy for quantitative measurement of the resulted lesion depth. Ten teeth were used for surface temperature measurement and two teeth for scanning electron microscopy (SEM). Extra twelve human molars were used for the intrapulpal temperature measurement. The absorbance of fluoride at 445 nm was measured. Results: The means of lesion depth for the C, L, F, and FL groups were 123.48 (±21.93), 112.33 (±20.42), 99.58 (±30.68), and 89.03 (±30.38) µm, respectively. The pairwise differences of the L, F, and FL groups compared with the C group were significant (p < 0.05). The differences between groups were tested: FL versus L p=0.02, F versus L p=0.16, and FL versus F p=0.91, and the difference of the F versus FL was not significant (p=0.91). Temperature increment at the enamel surface and pulp roof were ∆T = 16.67 (±4.11) and 2.12 (±0.66)°C, respectively. The topical fluoride absorbance at 445 nm is five orders higher than that at 810 nm. SEM shows that after laser irradiation the enamel surface was intact and without thermal damage. Conclusions: The 445 nm laser irradiation may be useful for caries prevention, and its effectiveness is lower than those previously achieved using the argon ion laser.


Assuntos
Cárie Dentária/prevenção & controle , Fluoretos Tópicos/uso terapêutico , Lasers Semicondutores/uso terapêutico , Terapia com Luz de Baixa Intensidade , Animais , Bovinos , Cárie Dentária/tratamento farmacológico , Cárie Dentária/radioterapia , Suscetibilidade à Cárie Dentária , Esmalte Dentário/ultraestrutura , Polpa Dentária/ultraestrutura , Humanos , Microscopia Eletrônica de Varredura , Microscopia de Polarização , Dente Molar/ultraestrutura , Temperatura , Dente/ultraestrutura
2.
Microsc Res Tech ; 82(11): 1884-1890, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31400189

RESUMO

Determining surface topography of different tissues of the molar tooth with novel analytical methods has opened new horizons in dental surface measurements which characterize tooth surface quality in dentistry. Studying surface topological measurements and comparing surface morphology of hard tissue of the molar tooth are the ultimate goals of the present study. Ten molar teeth have been chosen for investigating their surface characteristics through image processing techniques. The power spectral density (PSD) and fast Fourier transform algorithms of every molar tooth containing enamel, dentin, and cementum have determined that the characterization of surface profiles is possible. As can be seen, PSD along with fractal dimensions leads to good results for teeth surface topography. Moreover, PSD angular plot assures appropriate description of surface.


Assuntos
Cemento Dentário/ultraestrutura , Esmalte Dentário/ultraestrutura , Dentina/ultraestrutura , Fractais , Dente Molar/ultraestrutura , Adulto , Cristalografia por Raios X , Análise de Fourier , Dureza/fisiologia , Humanos , Masculino , Microscopia de Força Atômica , Dente Molar/diagnóstico por imagem , Propriedades de Superfície
3.
Microsc Res Tech ; 82(10): 1668-1680, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31259458

RESUMO

The study aimed at finding an optimal combination of acid concentration and etching time when nitric acid is used as etchant for the study of the finer details of human dental enamel structure. Four hundred 2-3-mm-thick segments of facio-lingually sectioned human third molar crowns were assigned to 20 groups with 20 specimens in each group, each group differing with respect to acid concentration (0.1, 1, 2.5, and 5%) and etching time (15, 30, 45, 90, and 180 s). After etching and preparation, specimens were observed in the scanning electron microscope (SEM). Surface roughness/topography increased with increasing acid concentration and increasing etching time, but not in a linear fashion; generally, prisms tended to go from flat-surfaced to cone-shaped and prism sheaths from fissure-like to wedge-shaped. Intragroup variations and intergroup similarities were considerable. The two major enamel factors determining the etch effect are crystal orientation and prism sheath properties. Other factors, such as distribution of porosities and crystal quality, also contribute probably. Slight to moderate topography is best for observing the finer enamel structure, for example, etching with concentrations in the range 0.1-1% and with etching times in the range 15-90 s, the stronger the acid, the shorter the time. The depth effect of nitric acid is judged to be relatively small. Considerable variations in expression of prism cross-striations were observed. SEM observations of acid-etched enamel in carefully selected planes are a powerful method for the study of enamel structure, bearing in mind the artifactual aspects of the observed surface.


Assuntos
Ácidos/metabolismo , Esmalte Dentário/ultraestrutura , Corrosão Dentária/métodos , Humanos , Microscopia Eletrônica de Varredura , Dente Molar/ultraestrutura , Propriedades de Superfície , Fatores de Tempo
4.
Microsc Res Tech ; 82(9): 1419-1429, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31099955

RESUMO

The purpose of this study was to: (a) evaluate the role of enamel surface roughness on bond fatigue durability and (b) evaluate statistical differences in roughness values based on measurement technique, including the use of spatial filtering for optical profilometry (OP). OptiBond XTR (Kerr Corp), Prime & Bond elect (DENTSPLY Caulk), Scotchbond Universal (3 M Oral Care), and XTR pre-etched with Ultra-Etch phosphoric acid (35%) (Ultradent) self-etch adhesives were used to treat enamel. A flat ground enamel surface was included as a control. Atomic force microscopy (AFM) and OP were used to measure the surface topography of each enamel surface following the application of adhesives. AFM, OP, and filtered OP (FOP) roughness values, where FOP was designed to only include the lateral spatial resolution consistent with AFM roughness values, were collected. Spatial resolution filtering with OriginPro was used to compare line scans from the two imaging techniques and generate the FOP group. These micro- versus nanoscale lateral roughness values were correlated with shear bond and shear fatigue strengths of the adhesives bonded to enamel. Roughness values showed differences based on measurement technique and strong correlations with bond and fatigue strength. The filtered OP group demonstrated the importance of careful usage and reporting of atomic force microscopy and OP metrics in adhesive dentistry. Best practices for surface roughness analysis were also discussed.


Assuntos
Cimentos Dentários/análise , Esmalte Dentário/ultraestrutura , Análise de Falha de Equipamento/métodos , Microscopia de Força Atômica/métodos , Imagem Óptica/métodos , Propriedades de Superfície , Humanos , Dente Molar/ultraestrutura
5.
Methods Mol Biol ; 1922: 267-291, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30838584

RESUMO

X-ray micro CT has become a popular methodology for the nondestructive analysis of dental tissues and has been used extensively in the amelogenesis field. The aim of this chapter is to introduce ImageJ/Fiji to researchers new to CT scanning and the analysis of CT image data. The program can be applied to analyzing X-ray CT images of enamel but can be extrapolated to other tissues as well.


Assuntos
Esmalte Dentário/ultraestrutura , Processamento de Imagem Assistida por Computador/métodos , Software , Microtomografia por Raio-X/métodos , Animais , Densidade Óssea , Esmalte Dentário/química , Aprendizado de Máquina , Mandíbula/química , Mandíbula/ultraestrutura , Camundongos , Minerais/química , Dente Molar/química , Dente Molar/ultraestrutura
6.
Acta Biomater ; 88: 491-502, 2019 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-30776507

RESUMO

Treatment of carious root surfaces remains challenging due to the complex pathological processes and difficulty in restoring the original structure of root dentine. Current treatments targeting the de-/re-mineralisation processes are not entirely satisfactory in terms of the protection of the dentinal organic matrix and the highly organised structure of dentine. In this in vitro study, a cross-linking agent - proanthocyanidin (PA) was used in conjunction with a fluoride-based treatment - silver diamine fluoride/potassium iodide (SDF/KI) to putatively stabilise the organic dentinal framework as well as strengthen the collagen-mineral phase interaction. The effectiveness of this strategy was evaluated 24 h after application in terms of the distribution of ion uptake and microstructure of dentine after treatment as well as analysis of the nano-mechanical properties using a dynamic behaviour model. Results showed that individual use of SDF/KI significantly improved the surface microhardness and integrated mineral density (Z) up to 60 µm depth and the recovery of creep behaviour of demineralised dentine in the surface area compared to that treated with deionised distilled water (DDW). The combined treatment of PA and SDF/KI achieved a more homogenous mineral distribution throughout the lesions than SDF/KI alone; a more significant incremental increase in surface microhardness and Z was observed. Specifically, a superior effect on the subsurface area occurred with PA + SDF/KI, with significant improvements in microhardness, elastic modulus and recovery of creep behaviour of the demineralised dentine. Application of SDF/KI induced small discrete crystal formation distributed over the dentine surface and PA contributed to the formation of slit-shaped orifices of the dentinal tubules that were partially occluded. STATEMENT OF SIGNIFICANCE: Demographic transitions and improved oral health behaviour have resulted in increased tooth retention in elderly people. As a consequence, the risk of root dentine caries is increasing due to the age-associated gingival recession and the related frequent exposure of cervical root dentine. Root caries is difficult to repair because of the complex aetiology and dentine structure. The recovery of dentine quality depends not only on reincorporation of minerals but also an intact dentinal organic matrix and the organic-inorganic interfacial structure, which contribute to the biomechanics of dentine. With the capability of dentine modification, cross-linking agents were applied with a fluoride regimen, which improved its treatment efficacy of root caries regarding the distribution of ion uptake and recovery of dentine biomechanics.


Assuntos
Iodeto de Potássio/uso terapêutico , Proantocianidinas/uso terapêutico , Compostos de Amônio Quaternário/uso terapêutico , Cárie Radicular/tratamento farmacológico , Compostos de Prata/uso terapêutico , Módulo de Elasticidade , Fluoretos Tópicos/farmacologia , Fluoretos Tópicos/uso terapêutico , Dureza , Humanos , Processamento de Imagem Assistida por Computador , Dente Molar/diagnóstico por imagem , Dente Molar/efeitos dos fármacos , Dente Molar/patologia , Dente Molar/ultraestrutura , Iodeto de Potássio/farmacologia , Compostos de Amônio Quaternário/farmacologia , Cárie Radicular/diagnóstico por imagem , Cárie Radicular/patologia , Compostos de Prata/farmacologia , Microtomografia por Raio-X
7.
Microsc Res Tech ; 81(9): 997-1003, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30341967

RESUMO

The aim of the present study was to identify the stage during acid etching of dental enamel where scratches introduced by sectioning and grinding procedures were eliminated. Nitric acid was used as etchant. Four hundred 2-3 mm-thick longitudinal sections of human third molar crowns were assigned to 80 groups, each group differing with respect to grinding procedure (silicon carbide paper grit 600; 1,000; 1,200; and 1,200 + polishing), acid concentration (0.1%, 1%, 2.5%, and 5%) and etching time (15, 30, 45, 90, and 180 s). Observation of the specimens with scanning electron microscopy (SEM) showed that elimination of scratches was facilitated by increasing fineness of grinding paper and polishing, and by increasing acid concentration and increasing etching time. An acid concentration of 0.1% did not remove scratches totally irrespective of grinding procedure or etching time, 1% acid removed most scratches after 45-90 s, while 2.5% and 5% acids removed most scratches after 30-45 s. It is proposed that the scratches are eliminated/obscured through a combined effect of the acid and the inherent structure of the enamel. The results of the present study may serve as a guide in choosing the best procedures for obtaining scratch-free enamel surfaces through acid etching with the least possible loss of enamel substance. Research highlights Sectioning and grinding produce scratches in dental enamel. Scratches are eliminated by acid etching prior to SEM studies of enamel structure. Scratch elimination increases with increasing acid strength and etching time and is facilitated by finer grit grinding paper and polishing.


Assuntos
Condicionamento Ácido do Dente/métodos , Esmalte Dentário/ultraestrutura , Polimento Dentário/métodos , Microscopia Eletrônica de Varredura , Dente Molar/ultraestrutura , Esmalte Dentário/efeitos dos fármacos , Humanos , Dente Molar/efeitos dos fármacos , Ácido Nítrico/uso terapêutico , Resultado do Tratamento
8.
Sci Rep ; 8(1): 14052, 2018 09 19.
Artigo em Inglês | MEDLINE | ID: mdl-30232366

RESUMO

This study aims to explore the feeding ecology of two terrestrial papionins, Papio and Theropithecus from the Shungura Formation in Ethiopia, the most complete stratigraphic and paleontological record of the African Plio-Pleistocene. Two aspects were evaluated using Dental Microwear Texture Analysis: differences in diet between the extinct genera and their extant relatives, and any potential dietary fluctuations over time. Amongst more than 2,500 cercopithecid dental remains, 154 Theropithecus molars and 60 Papio molars were considered. Thirty-nine extant wild baboons and 20 wild geladas were also considered. The results show that diets of extinct monkeys from Member G already differed between genera as it is the case for their extant representatives. The shearing facets on the Theropithecus molars display significant variations in microwear textures, suggesting several dietary shifts over time. Two events point to higher intakes of herbaceous monocots (tougher than dicots foliages), at about 2.91 Ma (between members B and C) and at 2.32 Ma (between members E and F). These two events are separated by an inverse trend at about 2.53 Ma (between members C and D). Some of these variations, such as between members E and F are supported by the enamel carbon isotopic composition of herbivorous mammals and with paleovegetation evidence.


Assuntos
Dieta , Dente Molar/ultraestrutura , Papio/fisiologia , Theropithecus/fisiologia , Animais , Evolução Biológica , Isótopos de Carbono/análise , Etiópia , Extinção Biológica , Fósseis , Herbivoria , Dente Molar/química , Papio/anatomia & histologia , Theropithecus/anatomia & histologia
9.
Micron ; 115: 17-24, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30142494

RESUMO

In this study, natural molar human tooth specimens were investigated for determining their micro- and nanoscale structural morphology, chemistry and crystallinity. The differences were tracked comparatively for both enamel and dentin layers and at their interfaces. Although dental material structures are hard and tough and the cross-sectioning of these materials using mechanical methods is challenging, FIB-SEM dual-beam instruments serve for preparing ultra-thin homogenous lamella sections. In this work, both FIB-SEM and TEM based advanced characterization methods were applied to reveal different morphological characteristics of dental tissue via complementary imaging and diffraction analysis. In addition, SEM-EDS and Raman spectroscopy techniques provided additional information about the elemental distribution and the chemical composition differences of the dental tissues. According to electron microscopy examinations at the intersection between the enamel and the dentin layers, it was shown that the enamel was denser and polycrystalline, while the dentin layer was porous, fibrillar and of negligible long-range order, due to its tubular structure and organic components. In particular, EDS mapping and linescan analyses showed almost no differences in the elemental distribution. Raman results confirmed that both tissues had similar chemical composition except dentin showed spectral background effects in the spectrum due to its tubular structure and organic components.


Assuntos
Esmalte Dentário/química , Esmalte Dentário/ultraestrutura , Dentina/química , Dentina/ultraestrutura , Dente Molar/ultraestrutura , Adulto , Humanos , Microscopia Eletrônica de Transmissão , Análise Espectral Raman
10.
J Clin Pediatr Dent ; 41(5): 363-367, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28872986

RESUMO

OBJECTIVE: To compare the effect of different endodontic irrigants on microleakage of adhesives used within pulp chamber of primary molars. STUDY DESIGN: 72 Primary molars were divided into 6 groups, according to 3 irrigants and 2 adhesives used. After de-roofing the pulp chamber, pulp was extirpated. In 36 samples, pulp chambers were bonded with Xeno V+ after irrigation with either QMix (Group1); 17%EDTA+5%NaOCl (Group2) or normal saline (Group3) and in other half samples, pulp chambers were bonded with SinglebondUniversal after irrigation with either QMix (Group 4); 17%EDTA+5% NaOCl (Group5) or normal saline (Group 6). All the samples were restored with Filtek Z350. Ten teeth from each group were assessed for dye penetration. Two samples in each group were viewed under scanning electron microscope. Data was statistically analyzed using Mann-Whitney and Kruskal Wallis tests at a significance level of P < 0.05. RESULTS: Mean microleakage scores were: Group 1-1.5±0.70, Group 2-1.6±.51, Group 3-2.4±0.96, Group 4-1.2±0.42, Group 5-1.2±0.42, Group 6-1.1±0.32. CONCLUSIONS: Irrigation with QMix significantly reduced the microleakage of XenoV+ but had no significant effect on microleakage of SinglebondUniversal. Irrigation with EDTA/NaOCl or QMix had no detrimental effect on the sealing ability of either of the adhesive tested.


Assuntos
Infiltração Dentária/diagnóstico por imagem , Cavidade Pulpar/ultraestrutura , Microscopia Eletrônica de Varredura , Dente Molar/ultraestrutura , Irrigantes do Canal Radicular , Biguanidas , Cimentos Dentários , Humanos , Polímeros , Dente Decíduo/ultraestrutura
11.
PLoS One ; 12(8): e0183982, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28859165

RESUMO

In the current study, we evaluate the equivalent stiffness of peritubular reinforcement effect (PRE) of porous dentine optimized by the thickness of peritubular dentine (PTD). Few studies to date have evaluated or quantitated the effect of PRE on composite dentine. The miscrostructure of porous dentine is captured by scanning electron microscope images, and then finite element modeling is used to quantitate the deformation and stiffness of the porous dentine structure. By optimizing the radius of PTD and dentine tubule (DT), the proposed FE model is able to demonstrate the effect of peritubular reinforcement on porous dentine stiffness. It is concluded that the dentinal equivalent stiffness is reduced and degraded with the increase of the radius of DT (i.e., porosity) in the certain ratio value of Ep/Ei and certain radius of PTD, where Ep is the PTD modulus and Ei is the intertubular dentine modulus. So in order to ensure the whole dentinal equivalent stiffness is not loss, the porosity should get some value while the Ep/Ei is certain. Thus, PTD prevents the stress concentration around DTs and reduces the risk of DTs failure. Mechanically, the overall role of PTD appears to enhance the stiffness of the dentine composite structure. These results provide some new and significant insights into the biological evolution of the optimal design for the porous dentine microstructure. These findings on the biological microstructure design of dentine materials are applicable to other engineering structural designs aimed at increasing the overall structural strength.


Assuntos
Dentina/ultraestrutura , Dente Molar/ultraestrutura , Adulto , Força Compressiva , Dentina/fisiologia , Feminino , Dureza , Humanos , Masculino , Microscopia Eletrônica de Varredura , Dente Molar/fisiologia , Porosidade , Estresse Mecânico , Extração Dentária
12.
Acta Bioeng Biomech ; 19(1): 181-188, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28552933

RESUMO

of this study was to analyze the effects of carbon dioxide (CO2) laser light on the structure and elemental composition of dentine. METHODS: The evaluation was conducted on samples from extracted teeth. The surface of the dentine was exposed to the radiation from a CTL 1401 CO2 laser (Centre of Laser Technology, Poland). The radiation and frequency parameters were as follows: group I with 5 W and 1 Hz, group II with 10 W and 1 Hz, group III with 5 W and 5 Hz, and group IV with 10 W and 5 Hz. The altered dentine structure was macroscopically and microscopically evaluated using a Nova NanoSEM 200 Scanning Electron Microscope (FEI Europe) with integrated microanalysis X-ray system for elemental analysis in points. RESULTS: There were significant differences between groups in the macro- and microstructure of laser defects. CONCLUSIONS: CO2 laser radiation causes irreversible, destructive changes in dentine. The structural dentine lesions developed under the influence of the CO2 laser radiation may hinder proper adhesion of bonding systems with the damaged tissue. Laser defects in the structure should be treated like defects of noncarious origin requiring preparation and filling with composite materials in accordance with the procedures.


Assuntos
Dentina/química , Dentina/ultraestrutura , Lasers de Gás , Dente Molar/química , Dente Molar/ultraestrutura , Dentina/efeitos da radiação , Relação Dose-Resposta à Radiação , Técnicas In Vitro , Dente Molar/efeitos da radiação , Doses de Radiação
13.
Arch Oral Biol ; 73: 248-252, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27810382

RESUMO

OBJECTIVE: The present study was designed to elucidate whether three soluble N-ethylmaleimide-sensitive fusion protein attachment protein receptor (SNARE) core proteins, syntaxin-1, synaptosomal-associated protein of 25kDa (SNAP-25), and vesicle-associated membrane protein-2 (VAMP-2), are present in the dental pulp of the rat molar at both the light and electron microscopic levels. DESIGN: Immunohistochemistry for protein gene product 9.5 (PGP 9.5), a pan-neuronal marker, syntaxin-1, SNAP-25, and VAMP-2 was performed on decalcified rat molars for light and electron microscopic analyses. Double-immunolabeling of PGP 9.5 and the SNARE core proteins, as well as combinations of the SNARE core proteins, was also carried out. RESULTS: PGP 9.5-immunoreactive nerve fibers ran toward the coronal region, ramified at the subodontoblast layer, and formed the subodontoblastic nerve plexus. Most nerve fibers penetrated the predentin and dentin along the dentinal tubules. Most, if not all, nerve fibers displayed immunoreactivity for syntaxin-1, SNAP-25, and VAMP-2. Immunoelectron microscopic analyses confirmed the presence of immunoreactivity for the SNARE core proteins within the intradental axonal elements. CONCLUSIONS: The present findings suggest that, since SNARE core proteins participate in the docking and exocytosis of synaptic vesicles in the central nervous system, they may contribute to vesicle exocytosis from the dental nerve fibers even though there are no apparent synapses.


Assuntos
Polpa Dentária/inervação , Dente Molar/inervação , Fibras Nervosas/metabolismo , Proteínas SNARE/metabolismo , Animais , Axônios/metabolismo , Polpa Dentária/diagnóstico por imagem , Cavidade Pulpar/inervação , Cavidade Pulpar/metabolismo , Dentina/anatomia & histologia , Dentina/inervação , Dentina/ultraestrutura , Exocitose , Imuno-Histoquímica , Masculino , Microscopia Imunoeletrônica/métodos , Dente Molar/ultraestrutura , Fibras Nervosas/ultraestrutura , Proteínas do Tecido Nervoso/metabolismo , Odontoblastos/citologia , Odontoblastos/metabolismo , Ratos , Ratos Sprague-Dawley , Sinapses/química , Sinapses/ultraestrutura , Ubiquitina Tiolesterase/metabolismo
14.
Connect Tissue Res ; 58(5): 414-423, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27657550

RESUMO

AIMS: The structural organization of collagen from mineralized tissues, such as dentin and bone, has been a topic of debate in the recent literature. Recent reports have presented novel interpretations of the complexity of collagen type I at different hierarchical levels and in different tissues. Here, we investigate the nanostructural organization of demineralized dentin collagen following the digestion of non-collagenous components with a trypsin enzyme. MATERIALS AND METHODS: Dentin specimens were obtained from healthy third-molars, cut into small cubes, and polished down to 1 µm roughness. Samples were then demineralized with 10% citric acid for 2 min. Selected specimens were further treated with a solution containing 1 mg/ml trypsin for 48 hours at 37 °C (pH 7.9-9.0). Both untreated and trypsin digested samples were analyzed using SDS-PAGE, Field Emission Scanning Electron Microscopy (FE-SEM), and nanoindentation, where surface hardness and creep properties were compared before and after treatments. RESULTS: FE-SEM images of demineralized dentin showed the banded morphology of D-periodical collagen type I, which upon enzymatic digestion with trypsin appeared to dissociate longitudinally, consistently unraveling ~20 nm structures (microfibril bundles). Such nanoscale structures, to the best of our knowledge, have not been characterized in dentin previously. Mechanical characterization via nanoindentation showed that the unraveling of such microfibril bundles affected the creep displacement and creep rate of demineralized dentin. CONCLUSION: In summary, our results provide novel evidence of the organization of collagen type I from dentin, which may have important implications for the interaction of dental materials with the organic dentin matrix and the mechanical properties of mineralized tissues.


Assuntos
Colágeno Tipo I/química , Dentina/química , Matriz Extracelular/química , Dente Molar/química , Matriz Extracelular/ultraestrutura , Humanos , Dente Molar/ultraestrutura
15.
Arch Oral Biol ; 73: 151-160, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27770641

RESUMO

INTRODUCTION: The perception of pain varies individually. Chronic stress leads to analgesia. The use of animal chronic mild stress model to mimic human condition was previously developed and now applied in the evaluation of pain perception in rats with dentin hypersensitivity (DH). AIMS: Using DH model induced by dentin erosion (DE) mediated by acidic solution, the present study aimed the evaluation of the interaction of chronic stress and pain induced by DH in rats with DE. METHODS: DH was induced by ad libitum 30-day intake of acidic solution. Stress was induced by the New York subway model. Body weight was weekly taken, during treatment. Groups WO (water, no stress), WS (water and stress), EO (acidic solution, no stress) and ES (acidic solution, stress) were submitted to treatments. RESULTS: After 30 days, all groups were submitted to DH test assessed by cold water stimuli in the labial surface of molars, for 5s, and the rats responses were scored as grades 0, 0.5, 1, 2, or 3. After euthanasia, blood was taken to obtain the levels of corticosterone, stomachs were observed in fresh preparations, kidneys and livers were submitted to histological evaluation. Open field model supported stress evaluation, as did corticosterone analysis. Stressed animals showed significant increase in pain perception and a decrease in locomotion frequency, tending to be more frequent in the periphery of the arena, corroborating stressed behavior and the need of protection as a pain relief. Corticosterone levels were increased in the stressed rats with dentin erosion and also corroborate present findings. Finally, reduction in weight gain was impaired in stressed group with dentin erosion. CONCLUSION: The animal model enabled the evaluation of how chronic mild stress interfered in DH pain perception.


Assuntos
Sensibilidade da Dentina/fisiopatologia , Estresse Psicológico/fisiopatologia , Animais , Comportamento Animal/fisiologia , Peso Corporal/fisiologia , Corticosterona/sangue , Sensibilidade da Dentina/sangue , Sensibilidade da Dentina/patologia , Modelos Animais de Doenças , Masculino , Dente Molar/diagnóstico por imagem , Dente Molar/efeitos dos fármacos , Dente Molar/ultraestrutura , Tamanho do Órgão , Dor/etiologia , Ratos , Ratos Wistar , Estresse Psicológico/sangue , Estresse Psicológico/patologia , Erosão Dentária/fisiopatologia
16.
Aust Endod J ; 43(3): 115-122, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27885743

RESUMO

The aim of this study was to investigate (i) the effect of direct or indirect polymerisation of adhesive-impregnated ribbon fibre under 4-mm bulk-filled composites on fracture strength; (ii) to compare polyethylene ribbon fibre-reinforcement composites with short fibre-reinforced composite; and (iii) the effectiveness of polyethylene ribbon fibre according to the restorative materials used (low-viscous bulk-fill composite, high-viscous flowable composite or conventional paste composite). Seventy molars were divided into seven groups; (groups 1-2) Ribbond-reinforced Surefil-SDR; (group 3) Ribbond-reinforced G Aenial Flo; (group 4) Ribbond-reinforced G Aenial Posterior; (group 5) short fibre-reinforced composite everX Posterior; (group 6) unfilled cavity; (group 7) intact teeth. Ribbond was adopted to cavity walls by impregnating an adhesive and using a flowable composite. In group 1, adhesive-impregnated Ribbond was polymerised directly using a light-curing-unit, and indirectly in group 2 under 4-mm bulk-filled composite. Direct or indirect polymerisation of adhesive impregnated ribbon fibre under 4-mm bulk-filled composite did not change the fracture strength results. Polyethylene ribbon fibre-reinforced groups (groups 1-4) and short fibre-reinforced composite group (group 5) displayed similar results. Polyethylene ribbon fibre can be used safely under 4-mm bulk-filled composites. Ribbond-reinforced low-viscous bulk-fill, high-viscous flowable, and conventional paste composite exhibited similar fracture strength results.


Assuntos
Materiais Dentários/química , Análise do Estresse Dentário , Fraturas dos Dentes/fisiopatologia , Dente não Vital/fisiopatologia , Resinas Compostas , Restauração Dentária Permanente/métodos , Resistência à Flexão , Humanos , Microscopia Eletrônica de Varredura , Dente Molar/patologia , Dente Molar/ultraestrutura , Polietilenos , Tratamento do Canal Radicular/métodos , Fraturas dos Dentes/patologia
17.
Eur J Orthod ; 39(3): 235-242, 2017 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-27733487

RESUMO

Aim: The aim of this study is to evaluate and compare therapeutic effects of mesenchymal stem cell (MSCs) and osteoprotegerin (OPG) gene transfer applications on inhibition and/or repair of orthodontically induced inflammatory root resorption (OIIRR). Materials and methods: Thirty Wistar rats were divided into four groups as untreated group (negative control), treated with orthodontic appliance group (positive control), MSCs injection group, and OPG transfected MSCs [gene therapy (GT) group]. About 100g of orthodontic force was applied to upper first molar teeth of rats for 14 days. MSCs and transfected MSC injections were performed at 1st, 6th, and 11th days to the MSC and GT group rats. At the end of experiment, upper first molar teeth were prepared for genetical, scanning electron microscopy (SEM), fluorescent microscopy, and haematoxylin eosin-tartrate resistant acid phosphatase staining histological analyses. Number of total cells, number of osteoclastic cells, number of resorption lacunae, resorption area ratio, SEM resorption ratio, OPG, RANKL, Cox-2 gene expression levels at the periodontal ligament (PDL) were calculated. Paired t-test, Kruskal-Wallis, and chi-square tests were performed. Results: Transferred MSCs showed marked fluorescence in PDL. The results revealed that number of osteoclastic cells, resorption lacunae, resorption area ratio, RANKL, and Cox-2 were reduced after single MSC injections significantly (P < 0.05). GT group showed the lowest number of osteoclastic cells (P < 0.01), number of resorption lacunae, resorption area ratio, and highest OPG expression (P < 0.001). Conclusions: Taken together all these results, MSCs and GT showed marked inhibition and/or repair effects on OIIRR during orthodontic treatment on rats.


Assuntos
Terapia Genética/métodos , Transplante de Células-Tronco Mesenquimais/métodos , Osteoprotegerina/genética , Reabsorção da Raiz/terapia , Técnicas de Movimentação Dentária/efeitos adversos , Animais , Reabsorção Óssea/etiologia , Reabsorção Óssea/patologia , Reabsorção Óssea/terapia , Técnicas de Transferência de Genes , Masculino , Microscopia Eletrônica , Dente Molar/ultraestrutura , Osteoclastos/patologia , Osteoprotegerina/metabolismo , Ligamento Periodontal/metabolismo , Ratos , Ratos Wistar , Reabsorção da Raiz/etiologia , Reabsorção da Raiz/patologia , Técnicas de Movimentação Dentária/métodos
18.
J Contemp Dent Pract ; 17(10): 861-866, 2016 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-27794160

RESUMO

AIM: This study evaluated the influence of acid-etching time on collagen exposure in adhesive interfaces established on primary and permanent dentin. MATERIALS AND METHODS: Flat dentin surfaces were produced on sound primary molars and premolars (n = 8). The surfaces were divided into mesial and distal halves, and each half was etched with phosphoric acid for 5 or 15 seconds. The teeth were randomly allocated into two groups according to the adhesive system applied: Prime & Bond NT or Prime & Bond 2.1. After the adhesive application, the specimens were processed for Goldner's trichrome staining. The thickness of the uninfiltrated collagen zone (UCZ) in the hybrid layer was measured under optical microscopy. Data were analyzed by analysis of variance and Tukey tests (α = 0.05). RESULTS: The thickness of UCZ was adhesive dependent. Within the same substrate, the specimens treated with Prime & Bond 2.1 presented thicker UCZ when etched for 15 seconds. Collagen exposure was significantly higher for the primary teeth etched for 5 seconds and treated with Prime & Bond 2.1. CONCLUSION: The thickness of UCZ in hybrid layers is directly affected by acid-etching time and by the adhesive system applied. Primary dentin seems to be more susceptible to collagen exposure than is permanent dentin. CLINICAL SIGNIFICANCE: Both acid-etching time and adhesive system can influence the amount of exposed collagen interfering on resin-dentin bond quality, especially on primary dentin.


Assuntos
Condicionamento Ácido do Dente/métodos , Colágeno/ultraestrutura , Dentição Permanente , Dente Decíduo , Dente Pré-Molar/ultraestrutura , Colagem Dentária , Humanos , Microscopia , Dente Molar/ultraestrutura , Ácidos Fosfóricos , Fatores de Tempo
19.
Environ Sci Pollut Res Int ; 23(21): 21475-21484, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27510160

RESUMO

The "lead line" was described by Henry Burton in 1840. Rodents are used as sentinels to monitor environmental pollution, but their teeth have not been used to determine lead. To determine whether lead deposits can be observed in the teeth of lead-exposed animals, since the gingival deposits known as "lead line" would likely have a correlate in the calcified tissue to which the gums are opposed during life. Male Wistar rats were exposed to lead in the drinking water (30 mg/L) since birth until 60 days-old. Molars and the incisors of each hemimandible were analyzed by scanning electron microscopy (SEM) on regular and backscattered electrons (BSE) mode. Elements were determined using electron dispersive spectroscopy (EDS). Clean cervical margins were observed on control teeth, as opposed to the findings of extensive deposits on lead-exposed animals, even in hemimandibles that had been exhumed after being buried for 90 days. BSE/EDS indicated that those deposits were an exogenous material compatible with lead sulfite. Presence of calcium, phosphorus, magnesium, carbon, lead, and oxygen is presented. Lead-exposed animals presented marked root resorption. The lead deposits characterized here for the first time show that the "lead line" seen in gums has a calcified tissue counterpart, that is detectable post-mortem even in animals exposed to a low dose of lead. This is likely a good method to detect undue lead exposure and will likely have wide application for pollution surveillance using sentinels.


Assuntos
Exposição Ambiental , Monitoramento Ambiental/métodos , Poluentes Ambientais/metabolismo , Chumbo/análise , Dente Molar/química , Animais , Masculino , Microscopia Eletrônica de Varredura , Dente Molar/ultraestrutura , Ratos , Ratos Wistar , Fatores de Tempo
20.
Arch Oral Biol ; 71: 16-23, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27376762

RESUMO

OBJECTIVE: The etiology of dental microwear is incompletely understood, despite copious documentation of wear patterns from wild and captive specimens across numerous vertebrate taxa. Among the contested issues with respect to microwear formation is the question of whether materials softer than enamel (specifically, foods themselves) can produce wear features. DESIGN: We examine the creation of enamel microwear features in vitro from foods that vary in hardness and toughness on a sample of mammalian lower molars (pig, bear, deer, and primate). These experiments involved applying loads at a constant displacement rate perpendicular to an occlusal enamel surface. Changes in surface microwear textures were assessed after 10 loads. RESULTS: Our experiments demonstrate that even relatively soft foods free of exogenous abrasives modify surface texture to produce distinctive microwear fabrics. Consequently, these data provide clear evidence that materials softer than enamel are capable of indenting and abrading enamel surfaces. Foods with a relatively high elastic modulus are associated with larger and more extensive microwear features, although the relationship between food stiffness and rate of microwear formation does not appear to be a simple one. CONCLUSIONS: These observations refute recent arguments that food material is an insignificant agent in the formation and accumulation of enamel microwear. Relative hardness of ingested materials is only one factor in the etiology of microwear formation.


Assuntos
Alimentos , Desgaste dos Dentes/etiologia , Animais , Cervos , Fricção , Dureza , Técnicas In Vitro , Dente Molar/ultraestrutura , Primatas , Propriedades de Superfície , Suínos , Ursidae
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