Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 37
Filtrar
1.
J Affect Disord ; 321: 16-27, 2023 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-36272461

RESUMO

BACKGROUND: During the perinatal period, women's perceived quality of life (QOL) may be altered due to physiological, psychological, and bodily changes, as well as changes in family functioning. OBJECTIVES: to explore in a sample of women from the general population, the associations between physical and mental QOL at 1 year post-partum and i) pregnancy social support, demographic, socioeconomic, medical and child health-related factors, paternal and maternal psychological characteristics at 2 months and 1 year post-partum, ii) antenatal preventive measures (early prenatal interview/antenatal classes). METHODS: We used data from the "French Longitudinal Study since Childhood" (ELFE), a representative cohort of children and their parents followed from birth to adulthood. Data were collected from mothers in the maternity ward, at 2 months and 1-year post-partum. QOL was assessed using the SF12 physical (PCS-12) and mental (MCS-12) subscales. RESULTS: Women with both low PCS-12 and MCS-12 scores were more likely to have high maternal age and to experience psychological difficulties during pregnancy. They also had more frequent PNDS, quarrels with insults within the couple, low sleep time at 2 months postpartum, and more frequently received psychological, social and child caregiver support, and were more often housewives or students at 1-year post-partum. Others factors are specific for low PCS-12 or MCS-12. There was no association with antenatal preventive measure and QOL at 1-year post-partum. CONCLUSION: Factors influencing maternal QOL are multiple and multidimensional and can mostly be identified during the ante or early postnatal period. A graduated and coordinated preventive and curative pathway would improve women's health. An ecosystemic approach to pregnancy and the perinatal period could help preventing the negative effects of environment on mothers and thus infants during the "1000-day period".


Assuntos
Saúde Mental , Qualidade de Vida , Humanos , Lactente , Criança , Feminino , Gravidez , Adulto , Qualidade de Vida/psicologia , Estudos Longitudinais , Mães/psicologia , Parto
2.
Behav Res Ther ; 159: 104226, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36410111

RESUMO

Mitigating the COVID-19 related disruptions in mental health care services is crucial in a time of increased mental health disorders. Numerous reviews have been conducted on the process of implementing technology-based mental health care during the pandemic. The research question of this umbrella review was to examine what the impact of COVID-19 was on access and delivery of mental health services and how mental health services have changed during the pandemic. A systematic search for systematic reviews and meta-analyses was conducted up to August 12, 2022, and 38 systematic reviews were identified. Main disruptions during COVID-19 were reduced access to outpatient mental health care and reduced admissions and earlier discharge from inpatient care. In response, synchronous telemental health tools such as videoconferencing were used to provide remote care similar to pre-COVID care, and to a lesser extent asynchronous virtual mental health tools such as apps. Implementation of synchronous tools were facilitated by time-efficiency and flexibility during the pandemic but there was a lack of accessibility for specific vulnerable populations. Main barriers among practitioners and patients to use digital mental health tools were poor technological literacy, particularly when preexisting inequalities existed, and beliefs about reduced therapeutic alliance particularly in case of severe mental disorders. Absence of organizational support for technological implementation of digital mental health interventions due to inadequate IT infrastructure, lack of funding, as well as lack of privacy and safety, challenged implementation during COVID-19. Reviews were of low to moderate quality, covered heterogeneously designed primary studies and lacked findings of implementation in low- and middle-income countries. These gaps in the evidence were particularly prevalent in studies conducted early in the pandemic. This umbrella review shows that during the COVID-19 pandemic, practitioners and mental health care institutions mainly used synchronous telemental health tools, and to a lesser degree asynchronous tools to enable continued access to mental health care for patients. Numerous barriers to these tools were identified, and call for further improvements. In addition, more high quality research into comparative effectiveness and working mechanisms may improve scalability of mental health care in general and in future infectious disease outbreaks.


Assuntos
COVID-19 , Humanos , Saúde Mental , Pandemias , Revisões Sistemáticas como Assunto , Comunicação por Videoconferência
3.
J Affect Disord ; 293: 238-244, 2021 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-34217961

RESUMO

BACKGROUND: Given the high incidence of perinatal maternal depression, implementation of preventive actions is crucial. In France, two prenatal preventive measures are available to the general population: early prenatal interview (EPI) and antenatal classes (ANC). OBJECTIVE: To explore the independent associations between EPI and / or ANC and maternal depressive symptoms at 2 months postpartum. METHOD: We used data from the Etude Longitudinale Française depuis l'Enfance (ELFE), a French national representative cohort of children and their parents, followed-up from birth to early adulthood. Data concerning characteristics were collected from the mothers during the maternity stay and between 6/8 weeks' post-partum. The level of depressive symptoms was scored by the French version of the Edinburgh Postnatal Depression Scale (EPDS) between 6/8 weeks' post-partum. We considered EPDS score ≥10 indicative of postnatal psychological distress (PPD) and EPDS ≥12 for postnatal depressive symptoms (PNDS). After data imputation, multivariate logistic regression analysis was performed. RESULTS: Among the 16,411 mothers included in our sample, 26% benefited both from EPI and ANC, 31.1 % of ANC, 7.7% of an EPI and 35% of neither; 20,1% presented PPD and 12,1% PNDS. The likelihood of presenting PPD was significantly higher in mothers who had neither had EPI nor ANC (OR = 1.15 (95% CI : 1.01-1.30). There was no association between receiving or not an EPI and/or ANC and presenting PNDS. CONCLUSIONS: Antenatal preventive measures may be helpful to prevent PPD at 2 months' post- partum, while PNDS do not seem to be influenced by these actions.


Assuntos
Depressão Pós-Parto , Depressão , Adulto , Criança , Estudos de Coortes , Depressão Pós-Parto/diagnóstico , Depressão Pós-Parto/epidemiologia , Depressão Pós-Parto/prevenção & controle , Feminino , Humanos , Mães , Gravidez , Fatores de Risco
4.
Eur Psychiatry ; 30(5): 562-8, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25843027

RESUMO

BACKGROUND: There is debate as to whether maternal tobacco use in pregnancy is related to offspring behaviour later on. We tested this association examining multiple aspects of children's behaviour at age 5 and accounting for parental smoking outside of pregnancy, as well as child and family characteristics. METHODS: Data come from a prospective community based birth cohort study (EDEN; n=1113 families in France followed since pregnancy in 2003-2005 until the child's 5th birthday). Maternal tobacco use in pregnancy was self-reported. Children's socio-emotional development (emotional symptoms, conduct problems, symptoms of hyperactivity/inattention, peer relationship problems, prosocial behaviour) was assessed by mothers using the Strengths and Difficulties Questionnaire (SDQ) at age 5 years. Logistic regression analyses controlled for Inverse Probability Weights (IPW) of maternal tobacco use calculated based on study center, children's characteristics (sex, premature birth, low birth weight, breastfeeding), maternal characteristics (age at the child's birth, psychological difficulties and alcohol use in pregnancy, post-pregnancy depression, and smoking), paternal smoking in and post-pregnancy, parental educational attainment, family income, parental separation, and maternal negative life events. RESULTS: Maternal smoking in pregnancy only predicted children's high symptoms of hyperactivity/inattention (sex and study center-adjusted ORs: maternal smoking in the 1st trimester: 1.95, 95%CI: 1.13-3.38; maternal smoking throughout pregnancy: OR=2.11, 95%CI: 1.36-3.27). In IPW-controlled regression models, only children of mothers who smoked throughout pregnancy had significantly elevated levels of hyperactivity/inattention (OR=2.20, 95%CI: 1.21-4.00). CONCLUSIONS: Maternal tobacco smoking in pregnancy may contribute directly or through epigenetic mechanisms to children's symptoms of hyperactivity/inattention.


Assuntos
Transtorno do Deficit de Atenção com Hiperatividade/etiologia , Comportamento Materno , Relações Mãe-Filho , Fumar/efeitos adversos , Adulto , Criança , Pré-Escolar , Estudos de Coortes , Depressão/psicologia , Feminino , França , Humanos , Recém-Nascido , Masculino , Troca Materno-Fetal , Gravidez , Estudos Prospectivos , Fatores de Risco
5.
Psychol Med ; 45(9): 1999-2012, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25678201

RESUMO

BACKGROUND: Maternal depression in the pre- and postpartum period may set women on a course of chronic depressive symptoms. Little is known about predictors of persistently elevated depressive symptoms in mothers from pregnancy onwards. The aims of this study are to determine maternal depression trajectories from pregnancy to the child's fifth birthday and identify associated risk factors. METHOD: Mothers (N = 1807) from the EDEN mother-child birth cohort study based in France (2003-2011) were followed from 24-28 weeks of pregnancy to their child's fifth birthday. Maternal depression trajectories were determined with a semi-parametric group-based modelling strategy. Sociodemographic, psychosocial and psychiatric predictors were explored for their association with trajectory class membership. RESULTS: Five trajectories of maternal symptoms of depression from pregnancy onwards were identified: no symptoms (60.2%); persistent intermediate-level depressive symptoms (25.2%); persistent high depressive symptoms (5.0%); high symptoms in pregnancy only (4.7%); high symptoms in the child's preschool period only (4.9%). Socio-demographic predictors associated with persistent depression were non-French origin; psychosocial predictors were childhood adversities, life events during pregnancy and work overinvestment; psychiatric predictors were previous mental health problems, psychological help, and high anxiety during pregnancy. CONCLUSIONS: Persistent depression in mothers of young children is associated to several risk factors present prior to or during pregnancy, notably anxiety. These characteristics precede depression trajectories and offer a possible entry point to enhance mother's mental health and reduce its burden on children.


Assuntos
Adultos Sobreviventes de Eventos Adversos na Infância/psicologia , Ansiedade/psicologia , Depressão Pós-Parto/psicologia , Depressão/psicologia , Mães/psicologia , Complicações na Gravidez/psicologia , Estresse Psicológico/psicologia , Transtornos Relacionados ao Uso de Substâncias/psicologia , Adulto , Estudos de Coortes , Progressão da Doença , Emprego , Feminino , França , Humanos , Acontecimentos que Mudam a Vida , Estudos Longitudinais , Gravidez , Estudos Prospectivos , Fatores de Risco , Apoio Social
6.
Acta Psychiatr Scand ; 131(4): 307-17, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25289581

RESUMO

OBJECTIVE: To examine whether non-psychiatric hospitalizations rates were higher in those with mental disorders. METHOD: In a cohort of 15,811 employees, aged 35-50 years in 1989, mental disorder status was defined from 1989 to 2000. Hospitalizations for all-causes, myocardial infarction (MI), stroke, and cancer, were recorded yearly from 2001 to 2011. Negative binomial regression models were used to estimate hospitalization rates over the follow-up. RESULTS: After controlling for baseline sociodemographic factors, health-related behaviors, self-rated health, and self-reported medical conditions, participants with a mental disorder had significantly higher rates of all-cause hospitalization [incidence rate ratio, IRR=1.20 (95%, 1.14-1.26)], as well as hospitalization due to MI [IRR=1.44 (95%, 1.12-1.85)]. For stroke, the IRR did not reach statistical significance [IRR=1.37 (95%, 0.95-1.99)] and there was no association with cancer [IRR=1.01 (95%, 0.86-1.19)]. A similar trend was observed when mental disorders groups were considered (no mental disorder, depressive disorder, mental disorders due to psychoactive substance use, other mental disorders, mixed mental disorders, and severe mental disorder). CONCLUSION: In this prospective cohort of employees with stable employment as well as universal access to healthcare, we found participants with mental disorders to have higher rates of non-psychiatric hospitalizations.


Assuntos
Hospitalização/estatística & dados numéricos , Transtornos Mentais/complicações , Adulto , Feminino , Humanos , Masculino , Transtornos Mentais/diagnóstico , Transtornos Mentais/epidemiologia , Pessoa de Meia-Idade , Infarto do Miocárdio/diagnóstico , Infarto do Miocárdio/epidemiologia , Neoplasias/diagnóstico , Neoplasias/epidemiologia , Serviços de Saúde do Trabalhador , Estudos Prospectivos , Fatores de Risco , Fatores Socioeconômicos , Acidente Vascular Cerebral/diagnóstico , Acidente Vascular Cerebral/epidemiologia
7.
J Biomed Mater Res B Appl Biomater ; 66(1): 447-56, 2003 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-12808607

RESUMO

This in vivo study evaluated the fixation of two types of titanium implants with the use of an injectable calcium-phosphate (CaP) cement. The cement was either used to create a cement mantle (Type A implant) or as an additive to press-fit placed titanium plasma sprayed implants (Type B implant). The implants were placed in trabecular bone of the medial femoral condyle of goats and left in place for 2 and 10 weeks. Mechanical evaluation of the implant fixation was done by torque testing. This showed that for the Type A implants the calcium-phosphate cement's performance was significantly inferior (P < 0.05) to that of polymethylmethacrylate cement fixation. For the two-week Type B implants a significant increase (P < 0.05) in failure load was found for calcium-phosphate cemented implants compared with just press-fitted Type B implants. Histological evaluation revealed that for Type A implants, failure during torque testing occurred at the implant-cement interface. In contrast, for Type B implants, failure occurred in the bone-implant interface for press-fit-placed devices and in the cement layer for CaP-cemented devices. Further, the CaP cement was found to be overgrown with new formed bone already after 2 weeks of implantation. The cement showed resorption due to regular bone remodeling. On the basis of these observations, it was concluded that the use of injectable CaP cement might facilitate earlier loading of press-fit inserted titanium implants. Nevertheless, the results have to be confirmed in dynamical mechanical as well as loaded in vivo studies.


Assuntos
Cimentos Ósseos , Fosfatos de Cálcio , Próteses e Implantes , Titânio , Animais , Fenômenos Biomecânicos , Fosfatos de Cálcio/administração & dosagem , Feminino , Cabras , Injeções , Teste de Materiais , Osseointegração , Polimetil Metacrilato , Fatores de Tempo
8.
Biomaterials ; 24(15): 2623-9, 2003 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-12726716

RESUMO

RF magnetron sputter deposition was used to produce 0.1, 1.0 and 4.0 microm thick Ca-P coatings on TiO(2)-blasted titanium discs. Half of the as-sputtered coated specimens were subjected to an additional infrared heat treatment for 30s at 425-475 degrees C. X-ray diffraction demonstrated that infrared radiation changed the amorphous 4 microm sputtered coatings into an amorphous-crystalline structure, while the amorphous 0.1 and 1 microm changed in a crystalline apatite structure with the presents of tetracalciumphosphate as a second phase. Scanning electron microscopically examination of the sputtered coatings revealed that annealing of the 4 microm thick coatings resulted in the appearance of small cracks. Subsequently, the discs were implanted subcutaneous into the back of rabbits. After 1, 4, 8 and 12 weeks of implantation, the implants were retrieved and prepared for histological and physicochemical evaluation. Histological evaluation revealed that the tissue response to all coated implants was very uniform. A very thin connective tissue capsule surrounded all implants. The capsule was usually free of inflammatory cells. At the interface, there was a close contact between the capsule and implant surface and no inflammatory cells were seen. Physicochemical evaluation showed that the 0.1 and 1 microm thick amorphous coatings had disappeared within 1 week of implantation. On the other hand, the 4 microm thick amorphous phase disappeared during the implantation periods, which was followed by the precipitation of a crystalline carbonate apatite. Further, at all implantation periods the heat-treated 1 and 4 microm thick coatings could be detected. Occasionally, a granular precipitate was deposited on the heat-treated 4 microm thick coating. Fourier transform infrared spectroscopy showed the formation of carbonate apatite (CO(3)-AP) on the 4 microm thick amorphous coating and on the heat-treated specimens. On basis of our findings, we conclude that 1 microm thick heat-treated Ca-P sputter coating on roughened titanium implants appear to be of sufficient thickness to show bioactive properties, under in vivo conditions.


Assuntos
Fosfatos de Cálcio/química , Materiais Revestidos Biocompatíveis/química , Próteses e Implantes , Titânio/química , Animais , Feminino , Teste de Materiais , Microscopia Eletrônica de Varredura , Coelhos , Ondas de Rádio , Espectroscopia de Infravermelho com Transformada de Fourier , Propriedades de Superfície , Difração de Raios X
9.
J Biomed Mater Res ; 61(1): 9-18, 2002 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-12001240

RESUMO

The aim of this study was to investigate the physicochemical, biological, and handling properties of a new developed calcium phosphate (Ca-P) cement when implanted in trabecular bone. Ca-P cement consisting of a powder and a liquid phase was implanted as a paste into femoral trabecular bone of goats for 3 days and 2, 8, 16, and 24 weeks. The cement was tested using three clinically relevant liquid-to-powder ratios. Polymethylmethacrylate bone cement, routinely used in orthopedics, was used as a control. The Ca-P cement was easy to handle and was fast setting with good cohesion when in contact with body fluids. X-ray diffraction at the different implantation periods showed that the cement had set as an apatite and remained stable over time. Histological evaluation after 2 weeks, performed on 10 microm un-decalcified sections, showed abundant bone apposition on the cement surface without any inflammatory reaction or fibrous encapsulation. At later time points, the Ca-P cement implants were totally covered by a thin layer of bone. Osteoclast-like cells, as present at the interface, had resorbed parts of the cement mass. At locations where Ca-P cement was resorbed, new bone was formed without loss of integrity between the bone bed and the cement. This demonstrated the osteotransductive property of the cement, i.e., resorption of the material by osteoclast-like cells, directly followed by the formation of new bone. Histological and histomorphometrical evaluation did not show any significant differences between the Ca-P cement implanted at the three different liquid/powder ratios. The results indicate that the investigated Ca-P cement is biocompatible, osteoconductive, as well as osteotransductive and is a candidate material for use as a bone substitute.


Assuntos
Materiais Biocompatíveis , Cimentos Ósseos , Regeneração Óssea , Osso e Ossos/metabolismo , Fosfatos de Cálcio , Animais , Materiais Biocompatíveis/química , Cimentos Ósseos/química , Cimentos Ósseos/metabolismo , Osso e Ossos/ultraestrutura , Fosfatos de Cálcio/química , Feminino , Corantes Fluorescentes , Cabras , Fatores de Tempo , Difração de Raios X
10.
Vet Rec ; 145(12): 329-33, 1999 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-10530881

RESUMO

Ninety transponders (microchips), 45 made of bioglass, 30 made of acid-etched bioglass, and 15 made of bioglass and provided with a polypropylene cap, were inserted into 15 dogs in six different locations: on the left and right side of the head, and on the left and right shoulders, both cranial and caudal to the dorsum. The transponders were left in place for 16 weeks, during which their position was determined by means of an electronic reader and radiographs, and they were then retrieved and examined histologically. A clinical evaluation revealed that about half of the transponders inserted in all the shoulder locations had migrated to some extent, whereas the transponders in the head location had hardly moved. There were no differences in the extent of migration between the different types of transponders. Histological analysis showed that almost all the transponders were surrounded by a thin fibrous capsule with no sign of any gross inflammatory reaction.


Assuntos
Sistemas de Identificação Animal , Materiais Biocompatíveis , Cerâmica , Migração de Corpo Estranho/veterinária , Implantes Experimentais , Animais , Cães , Desenho de Equipamento , Feminino , Migração de Corpo Estranho/diagnóstico por imagem , Masculino , Polipropilenos , Radiografia
11.
J Biomed Mater Res ; 36(1): 75-83, 1997 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-9212391

RESUMO

To aim of this study was to investigate the bone response to calcium phosphate (Ca-P) plasma-spray and radiofrequency magnetron sputter-coated implants with comparable roughness. Therefore, tapered conical screw designed implants were installed in the trabecular bone of the femurs of nine goats. They were provided with two types of coatings, a plasma-spray dual coating of fluorapatite and hydroxyapatite (FA/HA-PS) and a titanium plasma-spray coating, covered with an amorphous Ca-P magnetron sputtercoating (TPS/Ca-P-a). These implants were evaluated histologically and mechanically after 3 months of implantation. A well-controlled method to apply and measure a torsional force to load the screw-type implants to the point of failure was introduced. All implants healed uneventful and were well fixed. No significant difference (Student t test, p > 0.05) for the torsional failure force was measured for both type of coatings. Nevertheless, SEM revealed differently situated fracture planes. Light microscopy showed intimate bone-implanted contact for both types of coatings; original drill margins were still visible. A lamellar type of bone with some remodeling lacunae was shown. Histomorphometry revealed a higher percentage of bone contact for the FA/HA-PS-coated implants (students t test, p < 0.05). Measurement of the amount of bone revealed more bone mass around TPS/Ca-P-a-coated implants (analysis of variance and Turkey multiple comparison, p < 0.05).


Assuntos
Materiais Biocompatíveis , Osso e Ossos/cirurgia , Fosfatos de Cálcio , Próteses e Implantes , Animais , Fenômenos Biomecânicos , Parafusos Ósseos , Osso e Ossos/anatomia & histologia , Osso e Ossos/fisiologia , Feminino , Fêmur/anatomia & histologia , Fêmur/fisiologia , Fêmur/cirurgia , Cabras , Teste de Materiais , Microscopia Eletrônica de Varredura , Estresse Mecânico , Propriedades de Superfície
12.
J Biomed Mater Res ; 35(1): 19-30, 1997 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-9104695

RESUMO

Various studies already have shown that the occurrence of oral implant failure is higher in the maxilla than in the mandible. To learn whether Ca-P coatings can improve the success rate of oral implants in the maxilla, three different plasma-sprayed, Ca-P-coated, self-tapping Brånemark implants were inserted in the trabecular bone of the maxilla. Before the insertion of the implants, the two first upper premolars of 16 goats were bilaterally extracted. Four months later, each animal received four types of implants: three different Ca-P-coated types and one uncoated. After an endosseous period of 6 months, the implants were provided with permucosal abutments. Four months later the animals were killed. At the end of the experiment, it appeared that 10 of the 16 installed noncoated implants had failed while of the 48 Ca-P-coated implants, only 6 had failed. All successful implants were retrieved and prepared for histomorphometrical evaluation of the bone and gingiva response. The Ca-P-coated implants showed a significantly greater percentage of bone in contact with the implant surface compared with the uncoated implants. The length of the epithelium was not significantly different for the coated compared to the uncoated implants, but the connective tissue was significantly thicker for the noncoated implants than for the Ca-P-coated implants. Also, measurements revealed that all coatings showed reduction in thickness. On the basis of these findings, we concluded that the application of Ca-P coatings (1) improves the bone-implant reaction, although all coatings reduced in thickness, and (2) is of benefit during the healing period in less mineralized trabecular bone.


Assuntos
Materiais Biocompatíveis , Parafusos Ósseos , Fosfatos de Cálcio , Implantação Dentária Endóssea , Maxila/cirurgia , Animais , Planejamento de Prótese Dentária , Falha de Restauração Dentária , Feminino , Cabras , Teste de Materiais , Maxila/patologia , Osseointegração
13.
Biomaterials ; 18(6): 483-8, 1997 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-9111952

RESUMO

The stability of radiofrequency (RF) magnetron sputtered calcium phosphate was studied under cyclically loaded conditions. The coatings were deposited on titanium bars and tested in either dry or wet conditions X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX) analysis and Fourier transform infrared (FTIR) spectroscopy were used to characterize the as-sputtered and tested coatings. XRD demonstrated that the amorphous structure after annealing at 650 C changed into a crystalline apatite structure. The residual stresses were determined by the XRD cos 2 i/i method. These residual film stresses were influenced by the coating conditions and the crystalline sputtered coating showed the presence of compressive stresses. SEM demonstrated that, after cyclic loading conditions in air, the crystalline sputter-coated Ti-6A1-4V bars showed a partial coating loss. Furthermore, in wet conditions (simulated body fluid) only the heat-treated sputter-coated bars appeared to be stable. On the other hand, the amorphous coating only showed signs of delamination in the more highly stressed regions, while in the less stressed regions a Ca-P precipitate was formed. On the basis of these results we conclude that calcium phosphate coatings subjected to cyclic loading conditions show an important difference in fatigue behaviour when tested in either dry or wet conditions.


Assuntos
Materiais Biocompatíveis/química , Fosfatos de Cálcio/química , Ondas de Rádio , Absorciometria de Fóton , Magnetismo , Teste de Materiais/métodos , Microscopia Eletrônica de Varredura , Espectroscopia de Infravermelho com Transformada de Fourier , Propriedades de Superfície , Difração de Raios X
14.
Biomaterials ; 18(6): 495-501, 1997 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-9111954

RESUMO

The aim of the present study is to determine the possibility of measuring the bone mineral density (BMD) around implants by dual energy X-ray absorptiometry (DEXA). Therefore, the trabecular BMD was measured close to 127-600 microns and at a distance from various uncoated and Ca-P-coated implants inserted into the femoral condyle of goals. The implants were left in situ for 12 weeks. In addition, the bone-implant interface was evaluated histologically. For comparative reasons the BMD of non-implanted lateral and medial femoral condyles was also measured. The reproducibility of the measurements, expressed as a coefficient of variation, was found to be 0.44%. Moreover, the regions closest to the implants exhibited a higher BMD than all other regions, and the regions located in the medial condyle showed a higher BMD than the lateral condylar regions. Although the histological sections of the implants in the medial condyle demonstrated more bone contact with the coated than with the uncoated implants, a higher density was measured around the uncoated implants. The results regarding the non-implanted condyles indicated a higher density in the medial than in the lateral condyle. In view of these results, we conclude that BMD around dental implants depends on the location of the implant and that DEXA appears to be an excellent tool for analysing bone-implant reactions.


Assuntos
Densidade Óssea , Substitutos Ósseos , Próteses e Implantes , Absorciometria de Fóton/métodos , Ligas , Animais , Feminino , Fêmur , Cabras , Hidroxiapatitas , Reprodutibilidade dos Testes , Fatores de Tempo , Titânio
15.
Biomaterials ; 18(2): 161-6, 1997 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-9022964

RESUMO

In previous experiments a new type of percutaneous device for implantation in soft tissue was designed, containing a sintered titanium fibre mesh. The devices are inserted by a so-called "two-phase' surgical technique with an intervening healing period of 3 months between insertion of the subcutaneous and percutaneous parts. From a clinical point of view, this time interval is too long. The aim of this study was to investigate whether it was possible to reduce the intervening healing period. The implants were inserted in the backs of nine goats. In each goat, six implants were placed with intervals of 1 week. Consequently, at the end of the experiment, in each goat six implants were present with implantation periods ranging from 1 to 6 weeks. After 6 weeks, the animals were killed and the implants with surrounding tissue were processed histologically. Analysis demonstrated that during the first 2 weeks an inflammatory response was present. Thereafter, no difference in tissue response was found between the various implantation periods. In conclusion, the experiment suggests that for titanium mesh percutaneous devices a 3-week healing period is sufficient between the installation of the subcutaneous and percutaneous parts.


Assuntos
Materiais Biocompatíveis , Próteses e Implantes , Titânio , Cicatrização , Ferimentos e Lesões/terapia , Animais , Cápsulas , Feminino , Cabras , Fatores de Tempo , Ferimentos e Lesões/patologia , Ferimentos e Lesões/fisiopatologia
16.
J Biomed Mater Res ; 34(1): 121-8, 1997 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-8978661

RESUMO

The response of bone of low density to uncoated, fluorapatite (FA), hydroxyapatite (HA), and hydroxyapatite heat treated (HAHT) plasma-sprayed coated implants was investigated 3 and 6 months after installation. Forty-eight threaded implants of commercially pure titanium were inserted into the maxilla of twelve goats according to a split-plot design. One goat died shortly after installation of the implants, five goats were sacrificed 3 months after installation, and the other six goats 6 months after installation. Histological evaluation revealed no difference in bone reaction between the 3- and 6-month implantation periods. In addition, probably due to the wide inter- and intra-animal variability, no significant difference between the 3- and the 6-month periods could be observed in the histomorphometrical measurements performed. Further, no significant differences were found in bone reaction among the various implant materials. Finally, qualitatively it appeared that all coatings showed reduction in coating thickness and that such reductions were most pronounced for the HA coatings.


Assuntos
Regeneração Óssea/efeitos dos fármacos , Fosfatos de Cálcio/farmacologia , Próteses e Implantes , Animais , Apatitas/química , Materiais Biocompatíveis , Feminino , Cabras , Histocitoquímica , Hidroxiapatitas/química , Maxila/diagnóstico por imagem , Maxila/efeitos dos fármacos , Maxila/crescimento & desenvolvimento , Radiografia , Propriedades de Superfície
17.
J Mater Sci Mater Med ; 8(9): 531-6, 1997 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-15348704

RESUMO

Four different implant materials were installed into the mandibular corner of goats to investigate the trabecular bone response in a mainly unloaded model. The implants were installed using a standardized technique and were left in situ for 12 weeks. One goat had to be sacrificed after surgery because of a broken rib; the other animals healed uneventfully. After sacrifice of the animals, the bone response to the uncoated and the three different Ca-P implants was evaluated histologically and histomorphometrically. Four sections of each implant were evaluated; two were located in the cortical and two in the trabecular bone. Of the 44 retrieved implants, 20 implants appeared to be installed partially in the mandibular canal, as clearly visible on the X-rays. These implants were not used in the histomorphometrical measurements. Histological evaluation showed that the trabecular and cortical bone reactions were similar; there was no significant difference in the percentage of bone contact nor in the amount of bone in contact with the implants. In conclusion this study showed that the mandibular corner is an unsatisfactory model for the installation of implants because of anatomical restrictions. Also, the experiment remained inconclusive about the influence of loading conditions on bone behaviour. Nevertheless, the histological results confirmed the bioactive properties of Ca-P coatings.

18.
ASAIO J ; 42(6): 961-7, 1996.
Artigo em Inglês | MEDLINE | ID: mdl-8959270

RESUMO

A percutaneous device, provided with a sintered titanium fiber web structure, was designed for implantation in soft tissue. The percutaneous device was inserted by a two stage surgical technique. Between the insertion of the subcutaneous and percutaneous part was an intervening healing period of 3 months. However, most clinicians prefer a one stage implant. Therefore, the authors wanted to investigate the soft tissue response to one stage and two stage percutaneous devices. The implants were inserted in the flanks of 12 goat. In each goat, one one stage and one two stage implant were placed and inspected on a regular base. It appeared that, during the experiments, significantly more one stage devices were extruded. Four months after the second surgical session, all successful implants with their surrounding tissues were retrieved for light microscopic and histomorphometric analysis. No difference in epidermal downgrowth and sulcus width was demonstrated between the implants. Furthermore, the fiber mesh was surrounded by a thin fibrous capsule free from inflammatory cells. Inside the fiber mesh structure, connective tissue was present with only scattered foci of inflammatory cells. An enhanced inflammatory tissue response was found inside the titanium mesh of one stage compared to two stage implants. This study showed that the two stage surgical procedure for implantation of a percutaneous device worked better than the one-stage surgical technique.


Assuntos
Diálise Peritoneal , Próteses e Implantes/efeitos adversos , Titânio/metabolismo , Animais , Feminino , Fibroblastos/citologia , Fibroblastos/patologia , Cabras , Complicações Intraoperatórias/prevenção & controle , Polietilenos/metabolismo , Porosidade , Complicações Pós-Operatórias/prevenção & controle , Próteses e Implantes/normas , Pele/citologia , Pele/lesões , Pele/patologia , Lesões dos Tecidos Moles , Cicatrização/fisiologia
19.
J Biomed Mater Res ; 31(3): 329-37, 1996 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-8806058

RESUMO

The bone response to different plasma-spray and magnetron-sputter calcium phosphate (Ca-P)-coated implants was evaluated in a rabbit animal model. Four types of Ca-P coatings have been investigated: a plasma-spray Ca-P coating (HA-PS), a heat-treated plasma-spray Ca-P coating (HA-PS/ht), an amorphous magnetron-sputter coating (Ca-P-a), and a crystalline magnetron-sputter coating (CA-P-c). Seventy-two specially designed cylindrical implants were inserted in the lateral and medial femoral condyles of 18 New Zealand White rabbits. The four differently coated implants were positioned in one animal according to a split-plot design. After implantation periods of 3, 6, and 9 weeks, the bone-implant interface was evaluated histologically. Besides descriptive light microscopical evaluation, quantitative histomorphometrical measurements were done to determine bone contact and the amount of bone surrounding the implant-bone interface. Light microscopical examination revealed that all types of coatings followed the same process of bone healing. Measurements of bone contact at 6 and 9 weeks did not reveal significant differences between the various coatings. For the amount of bone, in a circular region at a certain distance from the implant, the Ca-P-c-coated implants showed a significantly greater amount of bone after 6 weeks of implantation than did the other three Ca-P coatings. At 9 weeks this difference could no longer be measured. On the basis of these findings we concluded that magnetron-sputtered Ca-P coatings show the same process of bone healing as the plasma-sprayed Ca-P coatings when inserted into the trabecular femoral bone of rabbits.


Assuntos
Materiais Biocompatíveis , Fosfatos de Cálcio , Próteses e Implantes , Animais , Remodelação Óssea , Fosfatos de Cálcio/química , Feminino , Hidroxiapatitas , Processamento de Imagem Assistida por Computador , Teste de Materiais , Coelhos , Propriedades de Superfície , Fatores de Tempo , Titânio/química , Difração de Raios X
20.
Biomaterials ; 17(12): 1251-6, 1996 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-8799510

RESUMO

Dacron velour is often used to anchor a percutaneous device, like the catheter used in peritoneal dialysis. However, exit-site infections complicate this method of dialysis and are supposed to be related to the design of the catheter. In animal experiments, a percutaneous device provided with a titanium fibre mesh to anchor the implant was not affected by infectious complications. The purpose of this study was to compare the differences in soft tissue reaction to Dacron velour and titanium fibre mesh under the same experimental conditions. Therefore, we placed implants, provided with either Dacron or titanium mesh, subcutaneously in the dorsum of goats. The implants were left in situ for 4 months. Histological and histomorphological evaluations were performed. It was found that the soft tissue response inside the Dacron was mainly inflammatory, while the titanium mesh evoked good biocompatible behaviour. We concluded that the limited fibrous tissue ingrowth into the Dacron cuff has to be the reason for the observed high failure incidence of a percutaneous device.


Assuntos
Poliésteres , Próteses e Implantes , Titânio , Administração Cutânea , Animais , Materiais Biocompatíveis , Cateterismo , Feminino , Cabras , Microscopia , Diálise Peritoneal , Silicones
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA