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1.
Int J Mol Sci ; 25(8)2024 Apr 13.
Artigo em Inglês | MEDLINE | ID: mdl-38673912

RESUMO

In this work, we propose a comprehensive experimental study of the diffusion of nickel ions in combination with different cyclodextrins as carrier molecules for enhanced solubility and facilitated transport. For this, ternary mutual diffusion coefficients measured by Taylor dispersion method are reported for aqueous solutions containing nickel salts and different cyclodextrins (that is, α-CD, ß-CD, and γ-CD) at 298.15 K. A combination of Taylor dispersion and other methods, such as UV-vis spectroscopy, will be used to obtain complementary information on these systems. The determination of the physicochemical properties of these salts with CDs in aqueous solution provides information that allows us to understand solute-solvent interactions, and gives a significant contribution to understanding the mechanisms underlying diffusional transport in aqueous solutions, and, consequently, to mitigating the potential toxicity associated with these metal ions. For example, using mutual diffusion data, it is possible to estimate the number of moles of each ion transported per mole of the cyclodextrin driven by its own concentration gradient.


Assuntos
Ciclodextrinas , Níquel , Níquel/química , Ciclodextrinas/química , Difusão , Solubilidade , Íons/química
2.
J Clin Periodontol ; 50 Suppl 25: 38-54, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-35815425

RESUMO

AIM: To evaluate outcome measures, methods of assessment, and analysis in clinical studies on the rehabilitation of full-arch edentulism with implant-supported fixed or removable prostheses. MATERIALS AND METHODS: A protocol-oriented search was conducted in MEDLINE via PubMed, EMBASE, and Cochrane Library (PROSPERO registration CRD42021265179) from 1 January 2011 to 27 July 2021 to identify longitudinal studies reporting on the rehabilitation of edentulous patients with implant-supported prostheses. The primary aim of this study was the collection of all objectively reported outcomes in each study. Secondary aims included the description of the methods of assessment and analytical methods. Risk of bias was applied according to the study design (randomized controlled trial, cohort study, or descriptive pre-post study). Individual study data were extracted into an outcomes matrix. Outcomes were grouped into domains and descriptively analysed. A network diagram was generated to establish relationships between domains. The present review follows the PRISMA statement. RESULTS: The screening and selection processes resulted in the identification of 491 publications, corresponding to 421 different studies (cohorts of patients). Only 24% of the studies reported the use of EQUATOR network guidelines. Implant failure/survival was the most reported outcome (270 studies), but the criterion to determine implant failure and/or survival was frequently not described or was ambiguous. Implant success was much less frequently reported (88) and was based on several heterogenous composite definitions. Marginal bone levels (233 studies), technical complications (158), and clinical outcomes (150), including peri-implant soft tissue and implant stability assessment, were also frequently reported. Patient-reported outcome measures (PROMs) (145) and function-based outcomes (40) were predominantly reported in isolation from other outcomes and most frequently in removable restorations. While quality of life was evaluated using valid instruments, patient satisfaction was evaluated based on a common sense concept of satisfaction. Economic outcomes were under-reported (13). CONCLUSIONS: There is great heterogeneity in the criteria to define implant failure or survival and implant success, which prevents the comparison of rates across studies. Even though studies frequently report multiple outcomes, PROMs are usually reported in isolation from other outcomes. It would be valuable to have a set of core outcome variables and standardized methods of measurement for future studies.


Assuntos
Implantes Dentários , Humanos , Estudos de Coortes , Qualidade de Vida , Dentaduras , Avaliação de Resultados em Cuidados de Saúde , Prótese Dentária Fixada por Implante
3.
Clin Oral Implants Res ; 34 Suppl 25: 38-54, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-35815423

RESUMO

AIM: To evaluate outcome measures, methods of assessment, and analysis in clinical studies on the rehabilitation of full-arch edentulism with implant-supported fixed or removable prostheses. MATERIALS AND METHODS: A protocol-oriented search was conducted in MEDLINE via PubMed, EMBASE, and Cochrane Library (PROSPERO registration CRD42021265179) from 1 January 2011 to 27 July 2021 to identify longitudinal studies reporting on the rehabilitation of edentulous patients with implant-supported prostheses. The primary aim of this study was the collection of all objectively reported outcomes in each study. Secondary aims included the description of the methods of assessment and analytical methods. Risk of bias was applied according to the study design (randomized controlled trial, cohort study, or descriptive pre-post study). Individual study data were extracted into an outcomes matrix. Outcomes were grouped into domains and descriptively analysed. A network diagram was generated to establish relationships between domains. The present review follows the PRISMA statement. RESULTS: The screening and selection processes resulted in the identification of 491 publications, corresponding to 421 different studies (cohorts of patients). Only 24% of the studies reported the use of EQUATOR network guidelines. Implant failure/survival was the most reported outcome (270 studies), but the criterion to determine implant failure and/or survival was frequently not described or was ambiguous. Implant success was much less frequently reported (88) and was based on several heterogenous composite definitions. Marginal bone levels (233 studies), technical complications (158), and clinical outcomes (150), including peri-implant soft tissue and implant stability assessment, were also frequently reported. Patient-reported outcome measures (PROMs) (145) and function-based outcomes (40) were predominantly reported in isolation from other outcomes and most frequently in removable restorations. While quality of life was evaluated using valid instruments, patient satisfaction was evaluated based on a common sense concept of satisfaction. Economic outcomes were under-reported (13). CONCLUSIONS: There is great heterogeneity in the criteria to define implant failure or survival and implant success, which prevents the comparison of rates across studies. Even though studies frequently report multiple outcomes, PROMs are usually reported in isolation from other outcomes. It would be valuable to have a set of core outcome variables and standardized methods of measurement for future studies.


Scientific rationale for study: Consistent data on the outcomes of treatments for full-arch edentulism are fundamental for establishing high-quality clinical practices with effective impact on patients' lives. Principal findings: Despite the increasing number of studies assessing the rehabilitation of full-arch edentulism with implant-supported prostheses, there has been little adherence to reporting guidelines (EQUATOR network), resulting in high variability regarding the type of outcomes reported. The clinical performance of these restorations has been mostly evaluated using clinician-oriented and patient-reported outcomes. Assessment methods are frequently not described and vary across studies. Practical implications: It would be valuable to have a set of core outcome variables and standardized methods of measurement for future studies.


Assuntos
Implantes Dentários , Humanos , Estudos de Coortes , Qualidade de Vida , Dentaduras , Avaliação de Resultados em Cuidados de Saúde , Prótese Dentária Fixada por Implante
4.
Am J Hum Genet ; 102(6): 1018-1030, 2018 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-29754768

RESUMO

Coenzyme A (CoA) is an essential metabolic cofactor used by around 4% of cellular enzymes. Its role is to carry and transfer acetyl and acyl groups to other molecules. Cells can synthesize CoA de novo from vitamin B5 (pantothenate) through five consecutive enzymatic steps. Phosphopantothenoylcysteine synthetase (PPCS) catalyzes the second step of the pathway during which phosphopantothenate reacts with ATP and cysteine to form phosphopantothenoylcysteine. Inborn errors of CoA biosynthesis have been implicated in neurodegeneration with brain iron accumulation (NBIA), a group of rare neurological disorders characterized by accumulation of iron in the basal ganglia and progressive neurodegeneration. Exome sequencing in five individuals from two unrelated families presenting with dilated cardiomyopathy revealed biallelic mutations in PPCS, linking CoA synthesis with a cardiac phenotype. Studies in yeast and fruit flies confirmed the pathogenicity of identified mutations. Biochemical analysis revealed a decrease in CoA levels in fibroblasts of all affected individuals. CoA biosynthesis can occur with pantethine as a source independent from PPCS, suggesting pantethine as targeted treatment for the affected individuals still alive.


Assuntos
Cardiomiopatia Dilatada/enzimologia , Cardiomiopatia Dilatada/genética , Genes Recessivos , Mutação/genética , Peptídeo Sintases/genética , Sequência de Aminoácidos , Animais , Vias Biossintéticas , Cardiomiopatia Dilatada/diagnóstico , Carnitina/análogos & derivados , Carnitina/metabolismo , Pré-Escolar , Coenzima A/biossíntese , Demografia , Drosophila , Estabilidade Enzimática , Feminino , Fibroblastos/metabolismo , Coração/fisiopatologia , Sequenciamento de Nucleotídeos em Larga Escala , Homozigoto , Humanos , Lactente , Recém-Nascido , Imageamento por Ressonância Magnética , Masculino , Panteteína/administração & dosagem , Panteteína/análogos & derivados , Linhagem , Peptídeo Sintases/sangue , Peptídeo Sintases/química , Peptídeo Sintases/deficiência , Reprodutibilidade dos Testes , Saccharomyces cerevisiae/genética
5.
Clin Oral Implants Res ; 32(8): 998-1007, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34115893

RESUMO

OBJECTIVE: This prospective study aims to assess the 5-year clinical performance of implants with internal conical connection and platform-switched abutments in the posterior mandible. MATERIAL AND METHODS: Healthy adults missing at least two teeth in the posterior mandible and with a natural tooth mesial to the implant site received two or three adjacent implants. After a transmucosal healing period single crown restorations were cemented on platform-switched abutments. Changes in marginal bone levels were investigated in standardized periapical radiographs from surgery and loading (baseline) to 60-months post-loading. RESULTS: Twenty-four patients received 52 implants. Bone remodelling took place between surgery and loading (mean:-0.5, SD:±0.4 mm). From loading to 60 months, there was a mean bone change of 0.27 (SD:±0.47 mm) which stabilized 24 months after prosthesis delivery (mean:0.2, SD:±0.46 mm). 71.7% of all implants presented bone preservation at 60 months irrespective of the initial insertion depth. Two implants were lost after 5 years and the success rate was 95.1%. Patient enquiry revealed high satisfaction. CONCLUSION: Internal conical connection implants with platform-switched abutments presented a high success rate and preservation of marginal bone levels at the implant shoulder after 5 years of loading.


Assuntos
Perda do Osso Alveolar , Implantes Dentários , Adulto , Perda do Osso Alveolar/diagnóstico por imagem , Perda do Osso Alveolar/etiologia , Planejamento de Prótese Dentária , Prótese Dentária Fixada por Implante , Seguimentos , Humanos , Mandíbula/diagnóstico por imagem , Mandíbula/cirurgia , Estudos Prospectivos
6.
Medicina (Kaunas) ; 57(11)2021 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-34833455

RESUMO

Background and Objectives: This systematic review aimed to assess the literature focusing on the clinical management of traumatized teeth with Pulp Canal Obliteration (PCO) and propose an updated clinical decision-making algorithm. The present review follows the PRISMA guidelines and was registered on PROSPERO database (CRD42020200656). Materials and Methods: An electronic search strategy was performed in Pubmed, EBSCOhost and LILACS from inception to March 2021. Only anterior permanent teeth with PCO due to dental trauma were included. Regarding clinical approaches, only teeth managed with a "watchful waiting" approach, tooth bleaching or root canal treatment (RCT) were included. Quality assessment was performed using the JBI Critical Appraisal Tool for Case Reports. Results: Twenty case reports were selected, resulting in a total of 27 patients. The number of traumatized teeth diagnosed with PCO was 33. The "watchful waiting" approach was the most implemented clinical strategy. Discolored non-symptomatic PCO teeth were mostly managed with external bleaching. The prevalence of pulp necrosis (PN) was 36.4%. For teeth diagnosed with PN, non-surgical RCT was performed in 10 teeth and surgical RCT in one tooth. Guided endodontic technique was performed in six of those teeth. Conclusions: For discolored non-symptomatic PCO teeth, external bleaching is advocated and the RCT approach should not be implemented as a preventive intervention strategy. Symptomatic PCO teeth should follow regular endodontic treatment pathways. Clinical approach of teeth with PCO should follow a decision-making algorithm incorporating clinical and radiographic signs and patient-reported symptoms.


Assuntos
Cavidade Pulpar , Descoloração de Dente , Dentição Permanente , Humanos
7.
J Oral Rehabil ; 47(2): 221-228, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31705804

RESUMO

PURPOSE: In the definition of an occlusal scheme, clinicians should choose between conventional and computerised methods based on a careful appraise of the advantages and limitations. This study aims to assess the correlation between the two approaches in a clinical setting. METHODS: Twenty-four patients were included to compare different methods of occlusal contacts assessment on the posterior surfaces of flat mandibular appliances. In supine position, they were asked to clench with maximum strength, in the maximum intercuspation position with a 24 µm articulating paper positioned between the teeth and the appliance surface. An extra-oral photograph of the marks was taken (total N = 2082). They were visually classified based on a pre-defined scale (ie, conventional assessment) and with ImageJ analysis software (ie, photographic software assessment). Additionally, a computerised occlusal analysis was performed (ie, computerised assessment). Correlation analysis of the data achieved with conventional, photographic and computerised assessments was performed. RESULTS: Correlation between conventional and computerised assessments was weak (r = .265), whilst it was moderate between conventional and photographic assessments (r = .633), as well as between photographic and computerised assessments (r = .476). CONCLUSIONS: This investigation showed a weak-to-moderate correlation between different methods (ie, conventional, photographic and computerised) to assess occlusal marks. None of the three can actually be considered the standard of reference, but based on their specific features, it can bet suggested that the conventional method may be enough for most clinical purposes, unless otherwise proven.


Assuntos
Mandíbula , Software , Humanos
8.
Angew Chem Int Ed Engl ; 59(14): 5771-5781, 2020 03 27.
Artigo em Inglês | MEDLINE | ID: mdl-31863711

RESUMO

Designed peptides derived from the islet amyloid polypeptide (IAPP) cross-amyloid interaction surface with Aß (termed interaction surface mimics or ISMs) have been shown to be highly potent inhibitors of Aß amyloid self-assembly. However, the molecular mechanism of their function is not well understood. Using solution-state and solid-state NMR spectroscopy in combination with ensemble-averaged dynamics simulations and other biophysical methods including TEM, fluorescence spectroscopy and microscopy, and DLS, we characterize ISM structural preferences and interactions. We find that the ISM peptide R3-GI is highly dynamic, can adopt a ß-like structure, and oligomerizes into colloid-like assemblies in a process that is reminiscent of liquid-liquid phase separation (LLPS). Our results suggest that such assemblies yield multivalent surfaces for interactions with Aß40. Sequestration of substrates into these colloid-like structures provides a mechanistic basis for ISM function and the design of novel potent anti-amyloid molecules.


Assuntos
Peptídeos beta-Amiloides/antagonistas & inibidores , Polipeptídeo Amiloide das Ilhotas Pancreáticas/química , Fragmentos de Peptídeos/antagonistas & inibidores , Peptídeos/química , Sequência de Aminoácidos , Peptídeos beta-Amiloides/metabolismo , Microscopia de Fluorescência , Simulação de Dinâmica Molecular , Ressonância Magnética Nuclear Biomolecular , Fragmentos de Peptídeos/metabolismo , Peptídeos/metabolismo , Especificidade por Substrato
9.
Int J Obes (Lond) ; 43(6): 1305-1318, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30283080

RESUMO

BACKGROUND/OBJECTIVES: Individuals carrying loss-of-function gene mutations for the adipocyte hormone leptin are morbidly obese, but respond favorably to replacement therapy. Recombinant leptin is however largely ineffective for the vast majority of obese individuals due to leptin resistance. One theory underlying leptin resistance is impaired leptin transport across the blood-brain-barrier (BBB). Here, we aim to gain new insights into the mechanisms of leptin BBB transport, and its role in leptin resistance. METHODS: We developed a novel tool for visualizing leptin transport using infrared fluorescently labeled leptin, combined with tissue clearing and light-sheet fluorescence microscopy. We corroborated these data using western blotting. RESULTS: Using 3D whole brain imaging, we display comparable leptin accumulation in circumventricular organs of lean and obese mice, predominantly in the choroid plexus (CP). Protein quantification revealed comparable leptin levels in microdissected mediobasal hypothalami (MBH) of lean and obese mice (p = 0.99). We further found increased leptin receptor expression in the CP (p = 0.025, p = 0.0002) and a trend toward elevated leptin protein levels in the MBH (p = 0.17, p = 0.078) of obese mice undergoing weight loss interventions by calorie restriction or exendin-4 treatment. CONCLUSIONS: Overall, our findings suggest a crucial role for the CP in controlling the transport of leptin into the cerebrospinal fluid and from there to target areas such as the MBH, potentially mediated via the leptin receptor. Similar leptin levels in circumventricular organs and the MBH of lean and obese mice further suggest intact leptin BBB transport in leptin resistant mice.


Assuntos
Barreira Hematoencefálica/metabolismo , Encéfalo/metabolismo , Leptina/metabolismo , Camundongos Obesos/metabolismo , Obesidade Mórbida/metabolismo , Animais , Transporte Biológico , Barreira Hematoencefálica/diagnóstico por imagem , Western Blotting , Encéfalo/diagnóstico por imagem , Modelos Animais de Doenças , Fluorescência , Células HEK293 , Humanos , Imageamento Tridimensional , Camundongos , Imagem Molecular
10.
J Clin Periodontol ; 46(6): 678-687, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31025365

RESUMO

AIM: To compare the clinical performance and marginal bone levels of implants restored with platform-switching (PS) or platform-matching (PM) abutments. MATERIALS AND METHODS: Adult patients missing two or more adjacent teeth in the posterior mandible received 2-4 CAMLOG SCREW-LINE implants and were randomly allocated to the PM or PS group, receiving the corresponding prosthetic components from surgery onwards. Implants were conventionally loaded with single cemented crowns. Patients were followed annually for 5 years. Outcome measures were marginal bone level changes, implant survival, performance of the prosthetic components and clinical parameters plaque index, sulcus bleeding index and pocket probing depth. RESULTS: Thirty-three patients received 72 implants in the PM group, and thirty-five patients received 74 implants in the PS group. Sixty patients attended the final appointment, 31 had received PS components and 29 had received PM components with 65 and 63 implants, respectively. Global survival rate was 96.6% with no differences between groups (p = 0.647). After 5 years of functional loading, PS restored implants presented 0.23mm (95% CI: [0.03, 0.43], p = 0.025) lower marginal bone level changes. The two groups were declared non-equivalent. CONCLUSION: Patients requiring implant supported restorations in healed bounded or free end edentulous gaps of the mandible benefit from the use of PS components in terms of peri-implant marginal bone level maintenance, though it may not be clinically noticeable.


Assuntos
Perda do Osso Alveolar , Projeto do Implante Dentário-Pivô , Adulto , Coroas , Implantação Dentária Endóssea , Índice de Placa Dentária , Prótese Dentária Fixada por Implante , Seguimentos , Humanos , Mandíbula , Resultado do Tratamento
11.
Clin Oral Implants Res ; 30(1): 20-48, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30466192

RESUMO

AIM: The aim of this study was to compare clinical and radiographic outcomes of dental implants with different neck characteristics. METHODS: A protocol-oriented search aimed at the question: "In patients subjected to tooth replacement with screw-type dental implants does the modification of the implant neck macro- or microgeometry contribute to the improvement of survival rates and maintenance of the peri-implant marginal bone levels?" Primary outcomes were survival and marginal bone level (MBL) changes evaluated on randomized controlled trials with >10 participants and follow-up >1 year. Risk of bias was evaluated using the Cochrane Collaboration's tool. The review follows the PRISMA statement. RESULTS: Forty-three studies compared: (a) One- versus two-piece implants (N = 7); (b) Two-piece implants with different neck characteristics (machined and rough collars, microthreads, LASER microtexturing) (N = 21); (c) Two-piece implants with macrogeometry modifications (tapering, back-tapering, and scalloping) (N = 6). One- and two-piece implants showed similar survival (RR = 0.45, 95% CI: [0.12, 1.66], p = 0.23) and MBL changes (WMD = 0.09 mm, 95% CI: [-0.27, 0.45], p = 0.64) at 1-year post-loading. Machined collar implants have higher risk of early failure than rough collar implants (RR = 3.96, 95% CI: [1.12, 13.93], p = 0.03) and 0.43 mm higher bone resorption (95% CI: [0.0, 0.86], p = 0.05). Microthreads (WMD = 0.07 mm, 95% CI: [-0.01, 0.15], p = 0.10) and LASER microtexturing (WMD = 0.15 mm, 95% CI: [-0.35, 0.65], p = 0.56) do not reduce bone resorption. Scalloped implants have 1.26 mm higher resorption (95% CI: [0.72, 2.00], p < 0.001). CONCLUSIONS: One- and two-piece implants have similar survival and MBL changes. Rough collar implants have lower MBL changes than machined collar implants. Additional modifications to rough collars are irrelevant.


Assuntos
Implantes Dentários , Planejamento de Prótese Dentária , Titânio , Implantes Dentários/efeitos adversos , Humanos , Falha de Prótese , Propriedades de Superfície , Resultado do Tratamento
12.
Clin Oral Implants Res ; 30(10): 953-961, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31278767

RESUMO

OBJECTIVES: The purpose of this randomized clinical trial was to compare immediate and early loading protocols for mandibular overdentures with two-splinted narrow-diameter implants in thin, non-augmented residual ridge situations. MATERIAL AND METHODS: Each edentulous patient received two implants in the interforaminal region. If primary stability after implant placement was achieved, patients were randomized either to the immediate (48 hr post-surgery) or the early (2 weeks after surgery) loading group. In prosthetic rehabilitation, a bar prosthetic system with a titanium bar was used. Implant survival, success rates, and radiographic changes at the crestal bone level were evaluated after 1 year, and patient satisfaction was recorded at 1 and 6 months post-surgery. RESULTS: Twenty-four patients with a mean age of 67 ± 9 years were included. One patient passed away after 11 months due to treatment-independent reasons. In the 24 implants of the immediate loading group, the mean bone level change from surgery/loading to the first-year evaluation was 0.32 ± 0.80 mm (p = .066). Regarding the early group (22 implants), the mean bone level change from loading to 1 year was 0.34 ± 0.69 mm (p = .048). After 1 year, no differences could be detected between groups (p = .91) with a mean difference of 0.02 mm (95% CI: [-0.42, 0.47]). The mean implant survival and success rates were 100% for both groups. Patient satisfaction was high; however, at 6 months, there was a difference between groups regarding the ability to chew. CONCLUSIONS: Both loading protocols for mandibular overdentures supported by two-splinted narrow-diameter implants were successful at the 1-year follow-up.


Assuntos
Implantes Dentários , Revestimento de Dentadura , Idoso , Implantação Dentária Endóssea , Prótese Dentária Fixada por Implante , Seguimentos , Humanos , Mandíbula , Pessoa de Meia-Idade , Titânio , Resultado do Tratamento , Zircônio
13.
Clin Oral Implants Res ; 30(6): 588-593, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31006157

RESUMO

OBJECTIVE: The aim of this consensus meeting was to assess the influence of implant neck and abutment characteristics on peri-implant tissue health and stability. MATERIAL AND METHODS: Group and plenary discussions were based on two systematic reviews focusing on the effect of titanium implants with different collar designs/surface modifications and the abutment material on the stability of marginal bone levels (MBLs), peri-implant health, and survival rates. RESULTS: The changes in MBLs were not influenced by the abutment material and were also similar at one- and two-piece implants after one year of loading. Rough collar implants improved MBLs in comparison to machined collar implants. Additional modifications of the collar had no beneficial clinical effect on MBLs. Titanium abutments were associated with significantly higher increases in bleeding on probing when compared with zirconia abutments. CONCLUSION: MBLs are mainly influenced by the microstructure (i.e., rough surfaced) of the implant neck. Consensus statements and specific recommendations for future research were elaborated during the consensus meeting.


Assuntos
Dente Suporte , Implantes Dentários , Consenso , Titânio
14.
Odontology ; 107(3): 324-332, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30542934

RESUMO

To evaluate the effect of immersion in 3% sodium hypochlorite solution in the resistance to cyclic fatigue of three nickel-titanium (NiTi) rotary file systems, ProTaper Next (PTN), Hyflex CM (CM), and Hyflex EDM (EDM), in a mechanical model featuring axial movement. Ninety instruments of three different NiTi rotary file systems, PTN (size 25, 0.06 taper), CM (25, 0.06), and EDM (25/~, variable taper), were randomly divided according to a 3 × 3 factorial design and tested under dynamic immersion in a 3% NaOCl solution (1 or 5 min) or without immersion, making a total of 9 groups (n = 10). Files were tested in an artificial root canal with 45° angle and 5 mm radius apical curvature being submitted to back-and-forth movements until fracture. Statistical analysis was performed using two-way factorial ANOVA with Bonferroni post-hoc tests, at a significance level of 5%. Instruments were evaluated for reliability using a Weilbull approach. Regardless of the immersion treatment, PTN had on average 1200 ± 178 cycles to fracture, CM had 1949 ± 362, and EDM had 5573 ± 853, which was a significantly different (P < 0.01). The NaOCl immersion promoted a significant reduction in the mean number of cycles to fracture (P = 0.01), and was reflected in a significant reduction of the characteristic life of the instruments of the CM end EDM groups. Within this study conditions, EDM instruments performed better to cyclic fatigue followed by CM and then PTN. Immersion in NaOCl decreased the resistance to cyclic fatigue of all tested instruments, but affected more those manufactured from CM wire.


Assuntos
Ligas Dentárias , Hipoclorito de Sódio , Instrumentos Odontológicos , Falha de Equipamento , Teste de Materiais , Reprodutibilidade dos Testes , Preparo de Canal Radicular , Estresse Mecânico , Titânio
15.
Clin Oral Implants Res ; 28(1): 9-16, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25943536

RESUMO

BACKGROUND: Implant-abutment assembly stability is critical for the success of implant-supported rehabilitation. The intentional removal of the prosthetic components may hamper the achievement of the essential stability due to preload reduction in the screw joint and implant-screw mating surface changes. OBJECTIVE: To evaluate the effect of intentional abutment disconnection and reconnection in the stability of internal locking hex implants and corresponding abutments using the method of 3D digital image correlation. MATERIAL AND METHODS: Ten conical shape and internal hexagon connection implants were embedded in acrylic resin and assembled to prosthetic abutments with 30 Ncm torque and assigned to two groups: group 1 - tested for static load-bearing capacity at 30° off-axis for two times and group 2 - underwent intentional disconnection and reconnection between tests. Micro-movements were captured with two high-speed photographic cameras and analyzed with video correlation system in three spacial axes U, V and W. Screw abutment and internal implant thread morphology was observed with a field-emission scanning electron microscopy. RESULTS: After the intentional disconnection of the abutment, group 2 showed generally higher maximum displacements for U and V directions. Under 50N load, mean difference was 24.7 µm (P = 0.008) for U direction and -7.7 µm (P = 0.008) for V direction. No significant differences were found for maximum and minimum displacements in the W direction. Mean displacement of the speckle surface presented was statistically different in the two groups (P = 0.016). SEM revealed non-homogenous screw surfaces with scoring on group 2 plus striations and debris in the implant threads. CONCLUSION: Micro-movements were higher for the group submitted to intentional disconnection and reconnection of the abutment, particularly under average bite forces.


Assuntos
Dente Suporte , Projeto do Implante Dentário-Pivô , Implantes Dentários , Análise do Estresse Dentário , Humanos , Imageamento Tridimensional , Teste de Materiais , Microscopia Eletrônica de Varredura , Estresse Mecânico
16.
J Clin Periodontol ; 43(4): 374-82, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26847169

RESUMO

OBJECTIVE: Evaluation of differences in the clinical performance and crestal bone levels between implants restored with single crowns with platform-matched or platform-switched abutments after 3 years. MATERIAL AND METHODS: The study enrolled adult patients missing two or more adjacent teeth in the posterior mandible with natural teeth mesial to the implant site. Randomization followed open-flap implant insertion and the corresponding matching or switching healing abutments placed at surgery. Conventional loading was made with cemented crowns. Clinical follow-up took place annually after loading up to 3 years. Bone level changes were measured in standardized radiographs as the variation in crestal bone from one evaluation to the next. RESULTS: Sixty-three patients with a total of 135 implants (66 platform matching, 69 platform switching) were analysed. From surgery to 36 months, mean bone loss was 0.28 ± 0.56 mm for the platform-switching group and 0.68 ± 0.64 mm for the platform-matching group. A statistically significant difference was found between groups (p = 0.002) with an estimate of 0.39 mm (0.15-0.64, 95% CI) in favour of platform switching. CONCLUSIONS: After 3 years, platform-switching restorations showed a significant effect in the preservation of marginal bone levels compared to platform-matching restorations.


Assuntos
Mandíbula/cirurgia , Perda do Osso Alveolar/cirurgia , Coroas , Dente Suporte , Implantação Dentária Endóssea , Implantes Dentários , Planejamento de Prótese Dentária , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade
17.
Clin Oral Implants Res ; 27(6): 686-93, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26096450

RESUMO

OBJECTIVE: Long-term success of dental implants depends on healthy peri-implant soft tissues and adequate bone levels. This prospective study aims to assess bone level changes around implants with internal conical connection and platform-switching abutments in the posterior mandible. MATERIAL AND METHODS: Adult patients missing at least two teeth in the posterior mandible and with a natural tooth mesial to the implant site received two or three adjacent internal conical connection implants. After a minimum transmucosal healing period of 8 weeks, single crown restorations were cemented over platform-switching abutments. Changes in marginal bone levels were measured in standardized periapical radiographs from surgery and loading (baseline) to 12 months post-loading. RESULTS: Twenty-four patients received 52 implants. Bone remodeling took place between surgery and loading (-0.53 ± 0.40 mm). From loading to 12 months, there was a mean bone gain of 0.12 ± 0.42 mm which occurred mainly in the first 6 months after prosthesis delivery (0.11 ± 0.36 mm) and stabilized afterward. A total of 71.7% of all implants presented bone preservation or gain. No implant was lost at 1 year and the success rate was 100%. Patient inquiry revealed high satisfaction. CONCLUSION: Internal conical connection implants with platform-switching abutments presented high success rate and enhancement or preservation of marginal bone levels after 1 year of loading.


Assuntos
Perda do Osso Alveolar/cirurgia , Projeto do Implante Dentário-Pivô , Mandíbula/diagnóstico por imagem , Mandíbula/cirurgia , Perda do Osso Alveolar/diagnóstico por imagem , Coroas , Implantes Dentários , Prótese Dentária Fixada por Implante , Feminino , Alemanha , Humanos , Masculino , Pessoa de Meia-Idade , Satisfação do Paciente , Projetos Piloto , Portugal , Estudos Prospectivos , Inquéritos e Questionários
18.
J Adhes Dent ; 17(2): 107-16, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25911962

RESUMO

PURPOSE: This study compared the microtensile bond strengths (µTBS) of two etch-and-rinse (ER) (OptiBond FL [OBFL]; Prime & Bond NT [PBNT]) and three self-etching (SE) (Clearfil SE Bond [CSEB]; Xeno III [XIII]; Xeno V+ [XV+]) adhesives systems to bur-prepared human enamel considering active (AA) and passive (PA) application of the self-etching systems. MATERIALS AND METHODS: Ninety-six enamel surfaces were prepared with a medium-grit diamond bur and randomly allocated into 8 groups to receive adhesive restorations: G1: OBFL; G2: PBNT; G3: CSEB/PA; G4: CSEB/ AA; G5: XIII/PA; G6: XIII/AA; G7: XV+/PA; G8: XV+/AA. After composite buildup, samples were sectioned to obtain a total of 279 bonded sticks (1 mm2) that were submitted to microtensile testing (µTBS; 0.5 mm/min) after 24-h water storage (37°C). Etching patterns and adhesive interfacial ultramorphology were also evaluated with confocal laser scanning (CLSM) and scanning electron microscopy (SEM). Data was analyzed with one-way ANOVA (α = 0.05). Weibull probabilistic distribution was also determined. RESULTS: Regarding µTBS, both adhesive system and application mode yielded statistically significant differences (p < 0.05) among groups. ER adhesive systems together with CSEB/AA and XIII/PA recorded the highest and statistically similar bond strength results. XV+ presented very low bond strength values, regardless of the application mode. Among self-etching adhesives, CSEB produced significantly higher µTBS values when applied actively. Qualitative evaluation by SEM and CLSM revealed substantial differences between groups both in adhesive interfaces and enamel conditioning patterns. CONCLUSIONS: ER and SE adhesive systems presented distinctive bond strengths to bur-cut enamel. The application mode effect was adhesive dependent. Active application improved etching patterns and resin interfaces micromorphology.


Assuntos
Colagem Dentária , Cimentos Dentários/química , Esmalte Dentário/ultraestrutura , Preparo do Dente/instrumentação , Condicionamento Ácido do Dente/métodos , Resinas Compostas/química , Materiais Dentários/química , Análise do Estresse Dentário/instrumentação , Adesivos Dentinários/química , Diamante/química , Humanos , Cura Luminosa de Adesivos Dentários , Teste de Materiais , Microscopia Confocal , Microscopia Eletrônica de Varredura , Ácidos Polimetacrílicos/química , Cimentos de Resina/química , Estresse Mecânico , Propriedades de Superfície , Temperatura , Resistência à Tração , Fatores de Tempo , Água/química
19.
Materials (Basel) ; 17(12)2024 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-38930312

RESUMO

Implantoplasty is a technique increasingly used to remove the biofilm that causes peri-implantitis on dental implants. This technique of mechanization of the titanium surface makes it possible to eliminate bacterial colonies, but it can generate variations in the properties of the implant. These variations, especially those in fatigue resistance and electrochemical corrosion behavior, have not been studied much. In this work, fatigue tests were performed on 60 dental implants without implantoplasty, namely 30 in air and 30 in Hank's solution at 37 °C, and 60 with implatoplasty, namely 30 in air and 30 in Hank's solution at 37 °C, using triaxial tension-compression and torsion stresses simulating human chewing. Mechanical tests were performed with a Bionix servo-hydraulic testing machine and fracture surfaces were studied by scanning electron microcopyElectrochemical corrosion tests were performed on 20 dental implants to determine the corrosion potentials and corrosion intensity for control implants and implantoplasty implants. Studies of titanium ion release to the physiological medium were carried out for each type of dental implants by Inductively Coupled-Plasma Mass Spectrometry at different immersion times at 37 °C. The results show a loss of fatigue caused by the implantoplasty of 30%, observing that the nucleation points of the cracks are in the areas of high deformation in the areas of the implant neck where the mechanization produced in the treatment of the implantoplasty causes an exaltation of fatigue cracks. It has been observed that tests performed in Hank's solution reduce the fatigue life due to the incorporation of hydrogen in the titanium causing the formation of hydrides that embrittle the dental implant. Likewise, the implantoplasty causes a reduction of the corrosion resistance with some pitting on the machined surface. Ion release analyses are slightly higher in the implantoplasted samples but do not show statistically significant differences. It has been observed that the physiological environment reduces the fatigue life of the implants due to the penetration of hydrogen into the titanium forming titanium hydrides which embrittle the implant. These results should be taken into account by clinicians to determine the convenience of performing a treatment such as implantoplasty that reduces the mechanical behavior and increases the chemical degradation of the titanium dental implant.

20.
Nat Metab ; 6(5): 861-879, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38565923

RESUMO

White adipocytes function as major energy reservoirs in humans by storing substantial amounts of triglycerides, and their dysfunction is associated with metabolic disorders; however, the mechanisms underlying cellular specialization during adipogenesis remain unknown. Here, we generate a spatiotemporal proteomic atlas of human adipogenesis, which elucidates cellular remodelling as well as the spatial reorganization of metabolic pathways to optimize cells for lipid accumulation and highlights the coordinated regulation of protein localization and abundance during adipocyte formation. We identify compartment-specific regulation of protein levels and localization changes of metabolic enzymes to reprogramme branched-chain amino acids and one-carbon metabolism to provide building blocks and reduction equivalents. Additionally, we identify C19orf12 as a differentiation-induced adipocyte lipid droplet protein that interacts with the translocase of the outer membrane complex of lipid droplet-associated mitochondria and regulates adipocyte lipid storage by determining the capacity of mitochondria to metabolize fatty acids. Overall, our study provides a comprehensive resource for understanding human adipogenesis and for future discoveries in the field.


Assuntos
Adipogenia , Proteômica , Humanos , Proteômica/métodos , Metabolismo dos Lipídeos , Mitocôndrias/metabolismo , Gotículas Lipídicas/metabolismo , Proteoma/metabolismo , Adipócitos/metabolismo , Diferenciação Celular
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