RESUMO
OBJECTIVE: Understanding the effects of biological aging on human tissues has been a topic of extensive research. With the increase in healthy seniors and quality of life that topic is becoming increasingly important. In this investigation the effects of aging on the microstructure, chemical composition and hardness of human coronal dentin was studied from a comparison of teeth within "young" and "old" age groups. METHODS: The microstructure of dentin within three regions (i.e., inner, middle and outer) was analyzed using electron and optical microscopy. The mineral-to-collagen ratio in these three regions was estimated using Raman spectroscopy and the hardness was evaluated using microindentation. RESULTS: Results showed that there were significant differences in tubule density, tubule diameter and peritubular cuff diameter with depth. Although there was no difference in tubule density and diameter of the tubules between the age groups, there was a significant difference in the occlusion ratio. A significant increase in hardness between young and old patients was found for middle and outer dentin. An increase in mineral-to-collagen ratio from inner to outer dentin was also found for both groups. In old patients, an increase in mineral content was found in outer coronal dentin as a consequence of tubule occlusion. CONCLUSIONS: An increase in occlusion ratio, hardness, and mineral content was found in the dentin of adult patients with age. This increase is most evident in the outer coronal dentin.
Assuntos
Envelhecimento , Dentina/química , Dentina/ultraestrutura , Adolescente , Adulto , Fatores Etários , Idoso , Feminino , Dureza , Humanos , Técnicas In Vitro , Masculino , Microscopia Eletrônica de Varredura , Pessoa de Meia-Idade , Dente Serotino , Análise Espectral Raman , Propriedades de SuperfícieRESUMO
UNLABELLED: Surface modification of biomaterials has been shown to improve the biological response to dental implants. The ability to create a controlled micro-texture on the implant via additive surface modification techniques with bioactive nanohydroxyapatite (nanoHA) may positively influence guided tissue regeneration. OBJECTIVE: The main goal of this study was to produce micro-fabricated SiO(2) surfaces modified with nanohydroxyapatite particles and to characterize their influence on the biological response of Human Dental-Pulp Mesenchymal Stem Cells (hDP-MSCs) and Streptococcus mutans. MATERIALS AND METHODS: A combined methodology of sol-gel and soft-lithography was used to produce micropatterned SiO(2) thin films with different percentages of nanoHA micro-aggregates. The surfaces were characterized by SEM/EDS, FT-IR/ATR, AFM, XPS quantitative elemental percentage and contact angle measurements. Biological characterization was performed using hDP-MSCs cultures, while Streptococcus mutans was the selected microorganism to evaluate the bacterial adhesion on the thin films. RESULTS: Micropatterned SiO(2) surfaces with 0%, 1% and 5% of nanoHA micro-aggregates were successfully produced using a combination of sol-gel and soft-lithography. These surfaces controlled the biological response, triggering alignment and oriented proliferation of hDP-MSCs and significant differences in the adhesion of S. mutans to the different surfaces. SIGNIFICANCE: The micropatterned surfaces exhibited biocompatible behavior that induced an oriented adhesion and proliferation of hDP-MSCs while SiO(2) presented low bacterial adhesion. These results show that the combination of sol-gel with soft-lithography is a good approach to create micropatterned surfaces with bioactive nanoparticles for guided tissue regeneration.
Assuntos
Materiais Biocompatíveis/química , Materiais Revestidos Biocompatíveis/química , Materiais Dentários/química , Durapatita/química , Nanoestruturas/química , Dióxido de Silício/química , Anisotropia , Aderência Bacteriana/fisiologia , Biofilmes , Adesão Celular/fisiologia , Contagem de Células , Proliferação de Células , Sobrevivência Celular/fisiologia , Desenho Assistido por Computador , Polpa Dentária/citologia , Regeneração Tecidual Guiada/métodos , Humanos , Teste de Materiais , Células-Tronco Mesenquimais/fisiologia , Microscopia de Força Atômica , Microscopia Eletrônica de Varredura , Transição de Fase , Espectroscopia Fotoeletrônica , Espectrometria por Raios X , Espectroscopia de Infravermelho com Transformada de Fourier , Streptococcus mutans/fisiologia , Propriedades de Superfície , MolhabilidadeRESUMO
UNLABELLED: Titanium implants are the gold standard in dentistry; however, problems such as gingival tarnishing and peri-implantitis have been reported. For zirconia to become a competitive alternative dental implant material, surface modification techniques that induce guided tissue growth must be developed. OBJECTIVES: To develop alternative surface modification techniques to promote guided tissue regeneration on zirconia materials, for applications in dental implantology. METHODS: A methodology that combined soft lithography and sol-gel chemistry was used to obtain isotropic micropatterned silica coatings on yttria-stabilized zirconia substrates. The materials were characterized via chemical, structural, surface morphology approaches. In vitro biological behavior was evaluated in terms of early adhesion and viability/metabolic activity of human osteoblast-like cells. Statistical analysis was conducted using one-way ANOVA/Tukey HSD post hoc test. RESULTS: Isotropic micropatterned silica coatings on yttria-stabilized zirconia substrates were obtained using a combined approach based on sol-gel technology and soft lithography. Micropatterned silica surfaces exhibited a biocompatible behavior, and modulated cell responses (i.e. inducing early alignment of osteoblast-like cells). After 7d of culture, the cells fully covered the top surfaces of pillar microstructured silica films. SIGNIFICANCE: The micropatterned silica films on zirconia showed a biocompatible response, and were capable of inducing guided osteoblastic cell adhesion, spreading and propagation. The results herein presented suggest that surface-modified ceramic implants via soft lithography and sol-gel chemistry could potentially be used to guide periodontal tissue regeneration, thus promoting tight tissue apposition, and avoiding gingival retraction and peri-implantitis.
Assuntos
Cerâmica/química , Materiais Revestidos Biocompatíveis/química , Materiais Dentários/química , Osteoblastos/fisiologia , Dióxido de Silício/química , Ítrio/química , Zircônio/química , Adesão Celular/fisiologia , Linhagem Celular , Proliferação de Células , Sobrevivência Celular/fisiologia , Cristalografia , Implantes Dentários , Regeneração Tecidual Guiada Periodontal , Temperatura Alta , Humanos , Indicadores e Reagentes , Teste de Materiais , Microscopia Confocal , Microscopia Eletrônica de Varredura , Oxazinas , Transição de Fase , Análise Espectral Raman , Propriedades de Superfície , Fatores de Tempo , Difração de Raios X , XantenosRESUMO
While there has been rapid development of microfabrication techniques to produce high-resolution surface modifications on a variety of materials in the last decade, there is still a strong need to produce novel alternatives to induce guided tissue regeneration on dental implants. High-resolution microscopy provides qualitative and quantitative techniques to study cellular guidance in the first stages of cell-material interactions. The purposes of this work were (1) to produce and characterize the surface topography of isotropic and anisotropic microfabricated silica thin films obtained by sol-gel processing, and (2) to compare the in vitro biological behavior of human bone marrow stem cells on these surfaces at early stages of adhesion and propagation. The results confirmed that a microstamping technique can be used to produce isotropic and anisotropic micropatterned silica coatings. Atomic force microscopy analysis was an adequate methodology to study in the same specimen the sintering derived contraction of the microfabricated coatings, using images obtained before and after thermal cycle. Hard micropatterned coatings induced a modulation in the early and late adhesion stages of cell-material and cell-cell interactions in a geometry-dependent manner (i.e., isotropic versus anisotropic), as it was clearly determined, using scanning electron and fluorescence microscopies.
Assuntos
Regeneração Tecidual Guiada , Células Progenitoras Mieloides/citologia , Alicerces Teciduais , Técnicas de Cultura de Células , Proliferação de Células , Humanos , Microscopia de Força Atômica , Microscopia Eletrônica de Varredura , Microscopia de Fluorescência , Filmes Cinematográficos , Dióxido de Silício , Propriedades de SuperfícieRESUMO
The aim of this study was to evaluate the effectiveness of physiotherapy to improve the head posture and reduce the signs of bruxism in a group of bruxist children. A single-blind randomized clinical trial was performed. All the subjects were 3- to 6-year old, had complete primary dentition, dental and skeletal class I occlusion and were classified as bruxist according to the minimal criteria of the ICSD for bruxism. For each child, a clinical, photographic and radiographic evaluation of the head and cervical posture were realized with standardized techniques. The children were randomized in an experimental (n = 13) and a control (n = 13) group. A physiotherapeutic intervention was applied to the children of the experimental group once a week, until 10 sessions were completed. Afterwards, the cephalogram and the clinical and photographic evaluation of the head posture were measured again. The data were analysed with the t-test and Mann-Whitney test. The subjects of the experimental group showed statistically significant improvement in the natural head posture. The physiotherapeutic intervention showed to be efficient to improve the head posture at the moment of measurement in the studied children. The relationship between bruxism and head posture, if exists, seems to be worthwhile to examine.
Assuntos
Conscientização , Bruxismo/reabilitação , Movimentos da Cabeça , Postura , Estudos de Casos e Controles , Cefalometria , Vértebras Cervicais/anatomia & histologia , Criança , Pré-Escolar , Feminino , Cabeça/anatomia & histologia , Humanos , Masculino , Modalidades de Fisioterapia , Método Simples-Cego , Estatísticas não Paramétricas , Resultado do TratamentoRESUMO
The objective of the study was to analyse quantitatively palatal morphology in bruxist and non-bruxist children with mixed dentition. Twenty-three children with mixed dentition were classified as bruxist according to their anxiety level, audible occlusal sounds related by the parents and signs of temporomandibular disorders; 23 children were control subjects matched for gender, age, and dental formula. The maxillary dental arches of all subjects were reproduced from alginate impressions cast in dental stone with a standardized technique. The casts were digitalized and mathematical equations were used to obtain the form of the palate in the sagittal, frontal and horizontal planes. Bruxist children had a statistically significant longer palate in the sagittal plane than control children; palatal shape differed especially in correspondence of the third, fourth and fifth teeth, bruxist children showing a relatively higher palate than control children. In this pilot study, sagittal plane differences in the palate between bruxist and non-bruxist children matched for age and gender were found. Further investigations are needed to understand better the clinical implications of the findings. Results should be taken into account in the diagnosis of the occlusal development in children with parafunctions to prevent future abnormalities: a bruxist child may have bigger dental arches than a normal child.
Assuntos
Bruxismo/patologia , Palato/patologia , Bruxismo/diagnóstico , Bruxismo/fisiopatologia , Estudos de Casos e Controles , Criança , Simulação por Computador , Arco Dental/patologia , Dentição Mista , Feminino , Humanos , Masculino , Modelos Anatômicos , Palato/crescimento & desenvolvimento , Projetos PilotoRESUMO
UNLABELLED: The aim of the present study was to compare the head position and dental wear of bruxist and non-bruxist children with primary dentition. METHODS: All the subjects had complete primary dentition, dental and skeletal class I occlusion and were classified as bruxist or non-bruxist according to their anxiety level, bruxism described by their parents and signs of temporomandibular disorders. The dental wear was drawn in dental casts and processed in digital format. Physiotherapeutic evaluation and a cephalometric radiograph with natural head position were also performed for each child to evaluate the cranio-cervical position for the bruxist group (n = 33) and the control group (n = 20). The variables of the two groups were compared, using the Student t-test and Mann-Whitney U-test. RESULTS: A more anterior and downward head tilt was found in the bruxist group, with statistically significant differences compared with the controls. More significant dental wear was observed in the bruxist children. CONCLUSIONS: Bruxism seems to be related to altered natural head posture and more intense dental wear. Further studies are necessary to explore bruxism mechanisms.