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1.
Eur Rev Med Pharmacol Sci ; 22(15): 4778-4783, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-30070311

RESUMO

OBJECTIVE: The aim of this study was to compare the frequency and volume of voids in root canals obturated with two different filling techniques using micro-computed tomography (micro-CT). MATERIALS AND METHODS: Forty single-rooted permanent teeth were selected and decoronated. The roots were instrumented with WaveOne (Dentsply Maillefer, Ballaigues, Switzerland) to a large size until working length and irrigated with 5.25% sodium hypochlorite and 17% EDTA. Then, the samples were filled using a single-cone (n = 20) or the GuttaCore technique (n = 20). The presence and volume (mm3) of voids (internal, external, and combined) was calculated in the coronal, medium, and apical thirds using micro-CT (SkyScan 1072; SkyScan, Kartuizersweg, Belgium). Statistical analyses were performed using the χ2-test and Kruskal-Wallis tests (p<0.05). RESULTS: The frequency and total volume of voids in the middle third and the external voids in the coronal third were statistically significant (p<0.05). Within the same group, both techniques (single-cone and Guttacore) showed statistically significant differences in external and internal voids (p<0.05). CONCLUSIONS: The GuttaCore technique showed better results in the coronal and medium thirds than the single-cone technique. Our results showed that the single-cone and GuttaCore techniques were comparable in the apical third (p>0.05).


Assuntos
Cavidade Pulpar/diagnóstico por imagem , Obturação do Canal Radicular/métodos , Preparo de Canal Radicular/métodos , Microtomografia por Raio-X/métodos , Restauração Dentária Permanente , Humanos , Processamento de Imagem Assistida por Computador , Materiais Restauradores do Canal Radicular/química
2.
Math Biosci ; 288: 159-165, 2017 06.
Artigo em Inglês | MEDLINE | ID: mdl-28390946

RESUMO

Bone quality is affected by trabecular architecture at microscopic level. Various abnormalities of bone tissue lead to altered strength and to an increased susceptibility to fracture, such as Osteoporosis and Osteoarthritis, two major health burdens of our society. These are two complex musculoskeletal diseases that mainly concern bone tissue. In the last twenty years, there has been a growing interest in finding an appropriate topological model for the micro-architecture of trabecular bone tissue. In particular, we prove that these models involve general topological spaces. The appropriate notion to deal with is that of CW-complex.


Assuntos
Osso Esponjoso/anatomia & histologia , Densidade Óssea , Osso Esponjoso/citologia , Osso Esponjoso/fisiologia , Humanos
3.
Arch Ital Biol ; 154(4): 103-117, 2016 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-28306130

RESUMO

Brain connectivity is associated to behavioral states (e.g. wake, sleep) and modified by physical activity although, to date, it is not clear which components (e.g. hypothalamus-pituitary-adrenal axis hormones, cytokines) associated to the exercise are involved. In this pilot study, we used extreme exercise (UltraTriathlon) as a model to investigate physical-activity-related changes of brain connectivity. We studied post-race brain synchronization during wakefulness and sleep as well as possible correlations between exercise-related cytokines/hormones and synchronization features. For wakefulness, global synchronization was evaluated by estimating from fMRI data (12 athletes) the brain global connectivity (GC). GC increased in several brain regions, mainly related to sensory-motor activity, emotional modulation and response to stress that may foster rapid exchange of information across regions, and reflect post-race internally-focused mental activity or disengagement from previous motor programs. No significant correlations between cytokines/hormones and GC were found. For sleep (8 athletes), synchronization was evaluated by estimating the local-(cortical) and global-related (thalamo- cortical) EEG features associated to the phenomenon of Sleep Slow Oscillations (SSO) of NREM sleep. Results showed that: power of fast rhythms in the baseline preceding the SSO increased in midline and parietal regions; amplitude and duration of SSOs increased, mainly in posterior areas; sigma modulation in the SSO up state decreased. In the post race, IL-10 positively correlated with fast rhythms baseline, SSO rate and positive slope; IL-1ra and cortisol inversely correlated with SSO duration; TNF-α and C-reactive protein positively correlated with fast rhythm modulation in the SSO up state. Sleep results suggest that: arousal during sleep, estimated by baseline fast rhythms, is increased; SSO may be sustained by cortical excitability, linked to anti-inflammatory markers (IL-10); thalamo-cortical entrainment, (sigma modulation), is impaired in athletes with higher inflammatory markers.


Assuntos
Mapeamento Encefálico , Encéfalo/fisiologia , Exercício Físico/fisiologia , Fases do Sono/fisiologia , Vigília/fisiologia , Adulto , Citocinas/sangue , Eletroencefalografia , Ensaio de Imunoadsorção Enzimática , Humanos , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Projetos Piloto
4.
Oncogene ; 35(9): 1180-92, 2016 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-26073083

RESUMO

Although the development of bone metastasis is a major detrimental event in prostate cancer, the molecular mechanisms responsible for bone homing and destruction remain largely unknown. Here we show that loss of miR-15 and miR-16 in cooperation with increased miR-21 expression promote prostate cancer spreading and bone lesions. This combination of microRNA endows bone-metastatic potential to prostate cancer cells. Concomitant loss of miR-15/miR-16 and gain of miR-21 aberrantly activate TGF-ß and Hedgehog signaling, that mediate local invasion, distant bone marrow colonization and osteolysis by prostate cancer cells. These findings establish a new molecular circuitry for prostate cancer metastasis that was validated in patients' cohorts. Our data indicate a network of biomarkers and druggable pathways to improve patient treatment.


Assuntos
Biomarcadores Tumorais/biossíntese , Neoplasias Ósseas/genética , MicroRNAs/biossíntese , Neoplasias da Próstata/genética , Animais , Neoplasias Ósseas/patologia , Neoplasias Ósseas/secundário , Linhagem Celular Tumoral , Transição Epitelial-Mesenquimal/genética , Regulação Neoplásica da Expressão Gênica , Proteínas Hedgehog/biossíntese , Humanos , Masculino , MicroRNAs/genética , Invasividade Neoplásica/genética , Neoplasias da Próstata/patologia , Transdução de Sinais/genética , Fator de Crescimento Transformador beta/biossíntese
5.
Minerva Stomatol ; 64(2): 87-96, 2015 Apr.
Artigo em Inglês, Italiano | MEDLINE | ID: mdl-25747429

RESUMO

AIM: In this work it has been evaluated how the use of an endocanalar brush (post-brush) is able to clean the post-space macroscopically and eliminate permanently any debris, leading to the determination of an enhancement of the dentine-cement interface adhesion. The retentive power of cylindrical-grooved in two different groups of dental elements (A GROUP and B GROUP) will be compared, cementing A group according to standard protocol and B group with treatment of Post-Brush. METHODS: Forty monoradicular elements were selected to carry out this experimental work. The roots were treated endodontically. Samples were divided randomly into two groups. For each group was used a different type of cementation. These tests were performed through the use of an electronic dynamometer. The samples were subjected to tensile strength to obtain a axial traction shear-stress and a subsequent separation of sample postreconstruction from root canal, at a loading maximum value recorded by the dynamometer right after the detachment. RESULTS: B GROUP, which included cemented cylindrical-rubbed posts before treatment of Post-Brush, has shown a tensile shear-stress at break performances higher than that A GROUP, in which cylindrical-rubbed posts have been cemented according to the standard protocol. CONCLUSION: Post-brush allows to obtain a better mechanical cleaning, going to remove gutta-percha residues, smear-layer and endodontic cement, which remain adhere on the canal walls otherwise they will not be removed completely by the use of the etching and the washing techniques as it tends to adhere to the canal walls.


Assuntos
Técnica para Retentor Intrarradicular , Tratamento do Canal Radicular , Cimentação , Retenção em Prótese Dentária , Distribuição Aleatória , Tratamento do Canal Radicular/métodos
6.
Acta Physiol (Oxf) ; 209(1): 62-8, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23638629

RESUMO

AIM: Body immersion induces blood redistribution (from peripheral to intrathoracic vessels) and is a powerful autonomic stimulus (activating both parasympathetic and sympathetic systems). For these reasons, concerns have been raised about the safety of diving for subjects with previous heart disease. The aim of this study was to evaluate cardiovascular changes occurring during recreational SCUBA diving, as assessed by underwater Doppler echocardiography. METHODS: Eighteen healthy experienced divers underwent a 2D Doppler echocardiography basally, during two 15' steps of still SCUBA diving at different depths (10 m followed by 5 m) and shortly after the end of immersion. RESULTS: During dive, left ventricular (LV) diastolic volume and early left ventricular filling significantly increased (5 m vs. basal: P < 0.05 and P < 0.01, respectively), while both deceleration time of the early filling rate and late diastolic filling velocity significantly decreased (5 m and 10 m dive vs. basal: P < 0.01). LV volume increase and diastolic filling changes persisted at postdive evaluation, where a significant decrease in heart rate was also observed (P < 0.01 as compared to basal, 5-m and 10-m dive). CONCLUSION: This study documents that shallow-depth SCUBA diving induces LV enlargement and diastolic dysfunction. Direct underwater evaluation by Doppler echocardiography could be an appropriate tool for unmasking subjects at risk for underwater-related accidents.


Assuntos
Mergulho/efeitos adversos , Ecocardiografia Doppler , Ventrículos do Coração/fisiopatologia , Volume Sistólico/fisiologia , Função Ventricular Esquerda/fisiologia , Adulto , Pressão Sanguínea/fisiologia , Ecocardiografia Doppler/métodos , Feminino , Frequência Cardíaca/fisiologia , Ventrículos do Coração/diagnóstico por imagem , Humanos , Masculino , Pessoa de Meia-Idade
7.
J Biol Regul Homeost Agents ; 27(4): 1077-82, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24382190

RESUMO

The present study was carried out to compare the differences in contact, height and contact area between the implant-abutment interface and the implant-healing cap interface of an implant system featuring a locking tapered connection by using X-ray micro-tomography. It was also conducted to test in vitro whether the implant-healing cap tapered interface is capable of preventing bacterial leakage from the implant well to the external environment. The images of the samples, acquired by the X-ray micro-tomography, after being processed with a dedicated software, showed a greater contact height (CH) in the implant-abutment sample (3.57 mm) compared to the implant-healing cap sample (2.52 mm). This was also true for the contact area that was equal to 40.63 mm2 in the implant-abutment sample and 25.14 mm2 in the implant-healing cap sample. No bacteria were detected both in the nutrient of the test group and of the negative control after 24 h. An increased contact height and contact area in a tapered connection, between the implant and the abutment, have demonstrated to offer mechanical and biological advantages, in a implant-healing cap tapered connection. The major concern regards the microbiological aspects of this connection. The implant-healing cap tapered connection provides an hermetic barrier to microbial passage in vitro, even though such connection features lower contact height and contact area compared to the implant-abutment connection of the same implant system.


Assuntos
Bactérias/isolamento & purificação , Dente Suporte/microbiologia , Implantes Dentários/microbiologia , Humanos , Microtomografia por Raio-X
8.
Int Endod J ; 44(4): 362-9, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21255040

RESUMO

AIM: To evaluate ex vivo the quality of root fillings completed by two thermoplasticized gutta-percha techniques (Thermafil and System B) and a cold gutta-percha technique (single point) by µCT analysis. METHODOLOGY: A total of 30 freshly extracted human single-rooted permanent teeth were selected. Root canals were prepared with ProTaper Universal instruments and then randomly divided into three groups (n = 10) depending on the filling technique. In group 1, canals were filled with a single-point technique; group 2 was filled with Thermafil; in group 3 System B was used. In group 1 and group 3, the root filling was performed using ProTaper Universal gutta-percha points, in group 2 Thermafil obturators were used; AH-Plus sealer was used in all groups. Assessment of the root filling was carried out by µCT, using a desktop X-ray micro focus CT scanner. Percentage of root canal filling materials and voids was calculated for each specimen. Data were statistically analysed using Kruskal-Wallis test (P < 0.05). RESULTS: Mean percentages of filling materials were 98.379 ± 1.204 in the single-point group, 99.023 ± 1.457 in Thermafil group, and 98.167 ± 3.432 in System B group. No statistically significant difference was found amongst the groups. CONCLUSION: All techniques produced comparable results in terms of percentage of filling and void distribution.


Assuntos
Obturação do Canal Radicular/métodos , Cavidade Pulpar/diagnóstico por imagem , Resinas Epóxi , Guta-Percha , Humanos , Garantia da Qualidade dos Cuidados de Saúde , Materiais Restauradores do Canal Radicular , Obturação do Canal Radicular/instrumentação , Raiz Dentária/diagnóstico por imagem , Microtomografia por Raio-X
9.
Undersea Hyperb Med ; 36(2): 93-101, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19462749

RESUMO

Breath-hold divers may experience haemoptysis during diving. Central pooling of blood as well as compression of pulmonary gas content can damage the integrity of the blood-gas barrier, resulting in alveolar hemorrhage. The single-breath carbon monoxide test (DL,CO) was used to investigate the blood-gas barrier following diving. The study population consisted of 30 divers recruited from a training course. DL,CO levels were measured before diving and at 2, 10 and 25 min after the last of a series of four dives to depths of 10, 15, 20 and 30 m. When compared to pre-diving values, DL,CO values increased significantly at 2 min following diving in all subjects except one. Thereafter values progressively decreased toward baseline at 10 and 25 min in all subjects but one, while in four divers DL,CO values decreased below baseline. The early but transient increase in DL,CO levels shortly after diving supports the persistence of capillary pooling of red blood cells following emersion. Persistence at 25 min of high DL,CO values in one subject could be attributed by lung CT to extravasation of blood into the alveoli. Early or late DL,CO values >10% below baseline values suggest the presence of pulmonary edema. The relatively high prevalence of DL,CO alterations found suggests caution on the safety of breath-hold diving activities.


Assuntos
Barreira Alveolocapilar/fisiologia , Monóxido de Carbono/metabolismo , Mergulho/fisiologia , Capacidade de Difusão Pulmonar/fisiologia , Adulto , Resistência das Vias Respiratórias/fisiologia , Barreira Alveolocapilar/metabolismo , Mergulho/efeitos adversos , Feminino , Hemoptise/etiologia , Humanos , Masculino , Alvéolos Pulmonares/fisiologia , Ventilação Pulmonar/fisiologia , Espirometria , Fatores de Tempo
10.
Gene Ther ; 15(19): 1330-43, 2008 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-18633445

RESUMO

Local gene transfer of the human Lim mineralization protein (LMP), a novel intracellular positive regulator of the osteoblast differentiation program, can induce efficient bone formation in rodents. To develop a clinically relevant gene therapy approach to facilitate bone healing, we have used primary dermal fibroblasts transduced ex vivo with Ad.LMP-3 and seeded on a hydroxyapatite/collagen matrix prior to autologous implantation. Here, we demonstrate that genetically modified autologous dermal fibroblasts expressing Ad.LMP-3 are able to induce ectopic bone formation following implantation of the matrix into mouse triceps and paravertebral muscles. Moreover, implantation of the Ad.LMP-3-modified dermal fibroblasts into a rat mandibular bone critical size defect model results in efficient healing, as determined by X-rays, histology and three-dimensional microcomputed tomography (3DmuCT). These results demonstrate the effectiveness of the non-secreted intracellular osteogenic factor LMP-3 in inducing bone formation in vivo. Moreover, the utilization of autologous dermal fibroblasts implanted on a biomaterial represents a promising approach for possible future clinical applications aimed at inducing new bone formation.


Assuntos
Doenças Ósseas/terapia , Fibroblastos/transplante , Terapia Genética/métodos , Peptídeos e Proteínas de Sinalização Intracelular/genética , Osteogênese/genética , Transdução Genética/métodos , Proteínas Adaptadoras de Transdução de Sinal , Adenoviridae/genética , Animais , Doenças Ósseas/diagnóstico por imagem , Doenças Ósseas/metabolismo , Osso e Ossos/diagnóstico por imagem , Osso e Ossos/metabolismo , Proteínas do Citoesqueleto , Fibroblastos/metabolismo , Expressão Gênica , Vetores Genéticos/administração & dosagem , Vetores Genéticos/genética , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteínas com Domínio LIM , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Modelos Animais , Ratos , Ratos Wistar , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Alicerces Teciduais , Tomografia Computadorizada por Raios X , Transplante Autólogo
11.
Undersea Hyperb Med ; 35(2): 83-90, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-18500072

RESUMO

Breath-hold diving induces, in marine mammals, a reduction of cardiac output due to a decrease of both heart rate and stroke volume. Cardiovascular changes in humans during breath-hold diving are only partially known due to the technical difficulty of studying fully immersed subjects. Recently, a submersible echocardiograph has been developed, allowing a feasible assessment of cardiac anatomy and function of subjects during diving. Aim of the study was to evaluate, by Doppler-echocardiography, the cardiovascular changes inducedby breath-hold diving in humans. Ten male subjects were studied by Doppler echocardiography in dry conditions and during breath-hold diving at 3 m depth. In addition 14 male subjects were studied, using the same protocol, before and during breath-hold diving at 10 m depth. At 3 m depth significant reductions in heart rate (-17%), stroke volume (-17%), cardiac output (-29%), left atrial dimensions, and deceleration time of early diastolic transmitral flow (DTE) were observed. At 10 m depth similar but more pronounced changes occurred. In particular, increase in early transmitral flow velocity became significant (+33%), while DTE decreased by 34%. At both depths dimensions of right cardiac chambers remained unchanged. Breath-hold diving at shallow depth induced, in humans, cardiovascular changes qualitatively similar to those observed in natural divers such as seals. The reduced dimensions of left atrium associated to a left ventricular diastolic pattern resembling that of restrictive/constrictive heart disease, suggest that the hemodynamic effects of diving could be explained, at least in part, by a constriction exerted on the heart by the reduced chest volume and the increased blood content of the lungs. Finally, the absence of dimensional changes in the right chambers suggests that most of the pulmonary blood shift occurred before cardiac imaging.


Assuntos
Débito Cardíaco/fisiologia , Diástole/fisiologia , Mergulho/fisiologia , Ecocardiografia Doppler/métodos , Frequência Cardíaca/fisiologia , Adulto , Velocidade do Fluxo Sanguíneo/fisiologia , Constrição , Ecocardiografia Doppler/instrumentação , Átrios do Coração/anatomia & histologia , Humanos , Masculino , Pessoa de Meia-Idade , Respiração , Volume Sistólico/fisiologia , Função Ventricular Esquerda/fisiologia
12.
Minerva Stomatol ; 57(4): 143-54, 2008 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-18427359

RESUMO

AIM: The aim of this study was to compare the shaping ability of Mtwo and ProTaper instruments in simulated curved root canals in resin blocks. METHODS: The study was carried out using 40 simulated canals in resin blocks, all of which had the same canal diameter (0.70 mm>D>0.20 mm), length (16 mm), and angle of curvature (40 degrees). These 40 canals were divided into 2 groups of 20 specimens. Both before and after instrumentation, all the resin specimens were photographed, and all the canals examined were measured at 4 different points of reference. Using a computer image analysis program, the photographs of corresponding sections were superimposed on one another. In this way we sought to evaluate the shaping ability of these 2 systems in relation to specific portions of the root canal, also with regard to maintenance of original canal curvature. The results were analysed using Student's t-test. RESULTS: Both rotary systems were found to respect the original root canal curvature, particularly in the areas most at risk of modification, namely the outer aspect of the curve in the apical third of the canal. The Mtwo instruments caused less transportation of the apex than the ProTaper instruments, but this difference was not statistically significant (P>0.05). CONCLUSION: According to the results of this study, both these instruments respected the original canal curvature, particularly in the areas at most risk of modification, and they also showed good shaping ability in curved canals, with minimum transportation of the apex.


Assuntos
Níquel , Tratamento do Canal Radicular/instrumentação , Titânio , Mecânica
13.
Minerva Stomatol ; 57(1-2): 9-16, 16-20, 2008.
Artigo em Inglês, Italiano | MEDLINE | ID: mdl-18427367

RESUMO

AIM: In this study Authors want to evaluate the static and dynamic flexural behaviour of innovative injection needles for dental anaesthesia comparing to the traditional needles. METHODS: Four kinds of innovative injection needles (Carpule Free Flow-Heraeus Kulzer), different for length and external diameter, have been evaluated in comparison with the traditional ones (Carpule-Heraeus Kulzer), dimensions being equal except for the internal diameter. Static stiffness tests (10 for each kind of needles, resulting in a totality of 80 tests) and fatigue bending test (10 for each kind of needles, each tested at 3 different bending angles, resulting in a totality of 240 tests) have been conducted following the ISO 9626 norms. The final comparison among the obtained data have been conducted using a one way statistical analysis of variance (ANOVA). RESULTS: After stiffness tests the Carpule Free Flow injection needles and the traditional ones showed the same static behaviour, resulting in statistical comparable values of mean deflection at the maximum load allowed by ISO norms tests, whereas the 0.4 mm external diameter showed a statistically significant difference because the Carpule Free Flow needles achieved lower deflection values. After dynamic bending tests at 20 degrees both needle types showed the same behaviour, whereas at 30 degrees bending the Carpule Free Flow injection needles showed a higher number of breaks comparing to normal type, up to a maximum value of breaks (10 out of 10) for the 0.4 mm external diameter needles. After 50 degrees fatigue bending tests the Carpule Free Flow needles came to the break point after lower number of cycles than the Carpule needles. CONCLUSION: This study pointed out that, among anaesthesia injection needles, the Carpule Free Flow needles not only showed better clinical characteristics but also a mechanical behaviour, both static and dynamic, statistically similar to traditional ones, according to international standards. After fatigue bending higher than 20 degrees, exclusively made in this research in order to simulate critical or extreme conditions, all analysed Carpule Free Flow needles have been broken after a lower number of cycles. It is concluded that it is recommended not to repeatedly bend this kind of needles at more than 90 degrees. At the end of this study it may be suggested that this kind of needles cannot be repeatedly bended at angles more than 90 degrees.


Assuntos
Anestesia Dentária/instrumentação , Agulhas , Desenho de Equipamento , Injeções/instrumentação , Mecânica
14.
Minerva Stomatol ; 56(3): 105-14, 2007 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-17327814

RESUMO

AIM: The aim of this study was to evaluate bond strength at the composite-adhesive-deep dentin interface following pre-treatment with sodium hypochlorite using 4 different types of enamel-dentin adhesive and a composite for the core. METHODS: From 60 healthy human molars, cylindrical samples (3 mm high) were obtained using a special slow-speed saw. Cavities with 2-5-mm diameters were made in all the samples. Samples were assigned to 8 groups, 4 groups were designated as experimental groups and were irrigated with NaOCl and the other 4 groups designated as control groups were irrigated with distilled water. Adhesive systems were applied to the samples and then restored using a core build-up composite. Samples were subjected to shear stress test using an electronic dynamometer. RESULTS: The data were analyzed using one-way ANOVA and the Tukey test (P<0.05). The results, in terms of bond strength, demonstrate that the two-step self-etch adhesive systems generate a stronger bond than the other systems considered in the study (P<0.05). The results also show that pre-treatment with hypochlorite does not seem to influence the bond strength of self-etch adhesive systems. CONCLUSIONS: This in vitro study demonstrates that there exist differences in bond strength between self-etch and etch & rinse adhesive systems on deep dentin pretreated with sodium hypochlorite to simulate endodontic treatment.


Assuntos
Colagem Dentária , Adesivos Dentinários , Dentina , Hipoclorito de Sódio/farmacologia , Coroa do Dente , Humanos
15.
Int Endod J ; 39(10): 755-63, 2006 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-16948660

RESUMO

AIM: To determine how instrument design affects the fatigue life of two nickel-titanium (Ni-Ti) rotary systems (Mtwo and ProTaper) under cyclic fatigue stress in simulated root canals. METHODOLOGY: Cyclic fatigue testing of instruments was performed in stainless steel artificial canals with radii of curvature of 2 or 5 mm and an angle of curvature of 60 degrees . A total of 260 instruments were rotated until fracture occurred and the number of cycles to failure were recorded. The morphology of Ni-Ti rotary instruments was investigated by measuring the volume of millimetre slices of each instrument size starting from the tip to the shank by means of microCT analysis. The fracture surface of three representative samples of each size was analysed by scanning electron microscopy (SEM). Data were analysed by one-way anova, Holm t-test, paired t-test and linear regression; the significance was determined at the 95% confidence level. RESULTS: Cycles to failure significantly decreased as the instrument volume increased for both the radii of curvature tested (P < 0.01). The radius of curvature had a statistically significant influence on the fatigue life of the instruments (P < 0.05). Larger instruments underwent fracture in less time under cyclic stress than smaller ones. SEM evaluation showed typical features of fracture through fatigue failure. CONCLUSIONS: The metal volume in the point of maximum stress during a cyclic fatigue test could affect the fatigue life of Ni-Ti rotary instruments. The larger the metal volume, the lower the fatigue resistance.


Assuntos
Ligas Dentárias , Instrumentos Odontológicos , Níquel , Preparo de Canal Radicular/instrumentação , Titânio , Análise de Variância , Análise do Estresse Dentário , Desenho de Equipamento , Falha de Equipamento , Imageamento Tridimensional , Modelos Lineares , Microscopia Eletrônica de Varredura
16.
J Telemed Telecare ; 12(4): 189-93, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16774700

RESUMO

We created a Web catalogue of approved telemedicine systems that authoritative Italian research bodies had made available for more general use. The evaluation process was divided into two stages: (1) classification of the telemedicine systems and rough preliminary evaluation; (2) assessment of the telemedicine products and services. The scoring method was applied to four well-known telemedicine systems that had been tested in health-care settings: an echocardiology teleconsulting and analysis system; a ward nursing management system; a virtual cooperative system for the management of oncology patients and a telepathology system based on remotely controlled microscopy. After technical revision during the standardization/qualification process, the applications were transferred successfully to eight new health-care facilities. The methodology achieved the main goal of providing effective tools, such as a set of quality control procedures for telemedicine and telehealth projects and a Web catalogue of telemedicine applications with a standardized level of quality, available to all interested parties.


Assuntos
Telemedicina , Catalogação , Humanos , Internet , Itália , Avaliação de Programas e Projetos de Saúde , Telemedicina/classificação , Telemedicina/normas
17.
J Appl Biomater Biomech ; 3(2): 128-33, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-20799233

RESUMO

Caries prevention should be an important goal of the dentistry practitioner. In addition to traditional preventive techniques, laser beam has been a recent suggestion. This study aimed to evaluate Nd:YAG laser treatment effects on dental enamel surfaces, irradiated at different energy levels, by scanning electron microscopy (SEM) observations and surface micro-hardness tests to evaluate if caries prevention can be achieved by laser treatment. Forty human teeth were divided in four groups of 10 specimens each: in three groups the enamel surface was treated with three different laser beam energy levels, 60, 120 and 160 mJ, in one group the enamel was not lased. Five samples from each group were subjected to the Vickers microhardness test and five samples underwent SEM investigation. Results of the microhardness test demonstrated no significant differences between treated and non-treated dental enamel samples. SEM observation demonstrated a rougher enamel surface in all treated groups: the 60 mJ treated group showed tooth surfaces with vertical scratches, the 120 mJ treated group showed the enamel surface covered by craters and cracks, and the 160 mJ treated group showed a completely changed enamel structure with columns separated by voids and with a glass-like surface. These investigations demonstrated that dental enamel laser treatment at low energy levels (not >60 mJ) produces a protective glass-like surface, without the loss of its integrity and could be an advisable technique to prevent caries. Higher energy laser treatment leads to modifications of the enamel morphology such as craters and cracks, even if it does not cause any change in enamel hardness characteristics, which could be more useful in conservative dentistry.

18.
J Appl Biomater Biomech ; 2(3): 156-61, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-20803433

RESUMO

Aesthetics is a very important element in dentistry, but requires the support of good mechanical performance. Quartz fiber used in post-endodontic reconstruction is an aesthetic material, although there is little research concerning its mechanical properties. This study evaluated the retentive property of post-endodontic reconstruction, composed of a quartz fiber post. Different thermal stresses were applied in vitro to post-endodontic reconstructions, in order to simulate oral thermal action on post-system dental structure linkage. We chose 30 human extracted teeth, endodontically treated and restored, and then divided them into three groups of 10 teeth. A different treatment was applied to each group before mechanical testing: in the 1st group no treatment was done (controls); in the 2nd group teeth were subjected, in a climatic chamber, to 10 thermo-cycles between 4 degrees C and 58 degrees C; in the 3rd group teeth were stored in a saline solution at 37 degrees C for 48 hr. The teeth then underwent tensile shear stress tests at break point using a computerized electronic dynamometer. After mechanical testing, two teeth from each group were longitudinally half-sectioned, sputter-coated in gold and observed by scanning electron microscopy (SEM). The extracted quartz fiber post of each tooth also underwent SEM observation. Mechanical test results demonstrated that thermal cyclic variations could affect bond stability between dental structures and posts in quartz fiber reconstructions, whereas their bond strength seemed unaffected by humidity increases. Quartz fiber post SEM observation demonstrated a homogeneous structure and a regular fiber disposition. Dental root canal morphology SEM images always showed a different thickness in the cement layer. (Journal of Applied Biomaterials & Biomechanics 2004; 2: 156-61).

19.
Implant Dent ; 9(3): 219-25, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-11307408

RESUMO

The aim of the study was to evaluate the mechanical performance and the structure of neoformed bone around hydroxyapatite-coated titanium fixtures according to guided bone regeneration techniques. Ten hydroxyapatite-coated titanium fixtures were inserted in the femurs of five rabbits, in which a cortical defect was created and after the insertion of the fixture, covered with a resorbable membrane obtained from bovine Achilles tendon collagen Type I (A implant). In the same femur, a second fixture was inserted in similar cavities without application of the membrane (B implant). After 60 days, the animals were sacrificed, and block sections of the femoral bone containing the implants were embedded in polymethylmetacrylate and subjected to tensile shear-stress at break testing. After the detachment of the implants from the bone, their surfaces were examined with a scanning electron microscope. Tensile shear-stress values for A and B implant specimens were comparable to some extent, but the former had a lower performance. In this regard, scanning electron microscope observations showed that the neoformed cortical bone present cervically around implant A was much thicker than around implant B.


Assuntos
Regeneração Óssea , Colágeno , Fêmur/cirurgia , Regeneração Tecidual Guiada Periodontal/instrumentação , Membranas Artificiais , Implantes Absorvíveis , Animais , Materiais Biocompatíveis , Bovinos , Materiais Revestidos Biocompatíveis , Implantes Dentários , Durapatita , Feminino , Fêmur/patologia , Fêmur/fisiopatologia , Masculino , Microscopia Eletrônica de Varredura , Modelos Animais , Osteogênese/fisiologia , Inclusão em Plástico , Polimetil Metacrilato , Coelhos , Estresse Mecânico , Propriedades de Superfície , Resistência à Tração , Titânio
20.
J Med Eng Technol ; 23(6): 216-21, 1999.
Artigo em Inglês | MEDLINE | ID: mdl-10738684

RESUMO

The problem of numerically classifying patterns, of crucial importance in the biomedical field, is here faced by means of their fractal dimension. A new simple algorithm was developed to characterize biomedical mono-dimensional signals avoiding computationally expensive methods, generally required by the classical approach of the fractal theory. The algorithm produces a number related to the geometric behaviour of the pattern providing information on the studied phenomenon. The results are independent of the signal amplitude and exhibit a fractal measure ranging from 1 to 2 for monotonically going-forwards monodimensional curves, in accordance with theory. Accurate calibration and qualification were accomplished by analysing basic waveforms. Further studies concerned the biomedical field with special reference to gait analysis: so far, well controlled movements such as walking, going up and downstairs and running, have been investigated. Controlled conditions of the test environment guaranteed the necessary repeatability and the accuracy of the practical experiments in setting up the methodology. The algorithm showed good performance in classifying the considered simple movements in the selected sample of normal subjects. The results obtained encourage us to use this technique for an effective on-line movement correlation with other long-term monitored variables such as blood pressure, ECG, etc.


Assuntos
Algoritmos , Fractais , Movimento , Reconhecimento Automatizado de Padrão , Processamento de Sinais Assistido por Computador , Eletrocardiografia , Marcha , Humanos , Modelos Teóricos , Corrida , Sensibilidade e Especificidade , Fatores de Tempo , Caminhada
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