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1.
Aquat Toxicol ; 271: 106926, 2024 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-38713993

RESUMO

Worldwide, the indiscriminate and escalating application of pesticides has led to extensive impacts on both the environment and non-target organisms. Phytoremediation, which employs plants to decontaminate environments, is a potential strategy for the mitigation of this damage. The present study assessed the phytoremedial potential of Salvinia auriculata, an aquatic macrophyte known to be effective for the removal of environmental contaminants. In the laboratory, Dendropsophus minutus tadpoles were exposed to different concentrations (0.035, 0.1, 1.0, and 1.5 mg/l) of the commercial insecticide Fipronil 800wg in two treatments - (i) simple exposure for 96 h, and (ii) exposure for 168 h in aquariums containing S. auriculata. In the first experiment, a mortality rate of 33.3 % was recorded at the highest Fipronil concentration (1.5 mg/l), and genotoxic parameters increased at all concentrations except 0.035 mg/L, in comparison with the control. In the second experiment, phytoremediation occurred at all the concentrations tested, with lower frequencies of cells with micronuclei, and binucleated, anucleated, and pyknotic nuclei being observed, in comparison with the first experiment. These findings highlight the potential effectiveness of S. auriculata for the phytoremediation of environments contaminated by pesticides and contribute to the understanding of the benefits of this approach for the protection and preservation of aquatic biodiversity.

2.
Braz Dent J ; 34(6): 140-149, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38133088

RESUMO

This study aimed to evaluate the influence of material and crown design on the biomechanical behavior of implant-supported crowns with hybrid abutment (HA) through three-dimensional (3D) finite element analysis. The study factors were the type of material used as the mesostructure or crown (zirconia, lithium disilicate, and hybrid ceramic) and the crown design cemented to the titanium base (mesostructure cemented to the titanium base and a crown cemented on it (HaC); hybrid crown-abutment, the abutment and crown are manufactured as a single piece and cemented to the titanium base (HC); monolithic crown cemented on the titanium base and screwed to the implant (CS); and monolithic crown cemented on the titanium base (CC). Four 3D models were constructed using an implant with an internal connection, and an oblique load of 130 N was applied at 45° to the long axis of the implant. The models were evaluated using the von Mises stress for crown, abutment, screw, and implant and maximum principal stress for bone tissues. The lowest stresses occurred in the groups with a lower elastic modulus material, mainly hybrid ceramics, considered a material with greater resilience. The cemented crown group presented the lowest stress values. The stresses were concentrated in the cervical region of the crown at the titanium crown/base interface. Mesostructures made of materials with a higher elastic modulus exhibited a higher concentration of stress. The presence of a screw hole increased the stress concentration in the ceramic crown. Cemented ceramic crowns exhibited better biomechanical behavior than screw-retained crowns.


Assuntos
Coroas , Titânio , Análise de Elementos Finitos , Titânio/química , Cerâmica/química , Zircônio/química , Análise do Estresse Dentário , Teste de Materiais , Projeto do Implante Dentário-Pivô , Desenho Assistido por Computador
3.
Polymers (Basel) ; 15(22)2023 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-38006133

RESUMO

The purpose of this study was to analyze the influence of Chitosan 0.2% in various final cleaning methods on the bond strength of fiberglass post (FP) to intrarradicular dentin. Ninety bovine incisors were sectioned to obtain root remnants measuring 18 mm in length. The roots were divided: G1: EDTA 17%; G2: EDTA 17% + PUI; G3: EDTA 17% + EA; G4: EDTA 17% + XPF; G5: Chitosan 2%; G6: Chitosan 2% + PUI; G7: Chitosan 2% + EA; G8: Chitosan 2% +XPF. After carrying out the cleaning methods, the posts were installed, and the root was cleaved to generate two disks from each root third. Bond strength values (MPa) obtained from the micro push-out test data were assessed by using Kruskal-Wallis and Dwass-Steel-Critchlow-Fligner tests for multiple comparisons (α = 5%). Differences were observed in the cervical third between G1 and G8 (p = 0.038), G4 and G8 (p = 0.003), G6 and G8 (p = 0.049), and Control and G8 (p = 0.019). The final cleaning method influenced the adhesion strength of cemented FP to intrarradicular dentin. Chitosan 0.2% + XPF positively influenced adhesion strength, with the highest values in the cervical third.

4.
J Indian Soc Periodontol ; 27(4): 392-398, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37593548

RESUMO

Background: To analyze through finite element analysis the stress distribution in peri-implant bone tissues, implants, and prosthetic components induced by the socket shield (SS) technique in comparison to other techniques used to treat tooth loss. Materials and Methods: A three-dimensional model of a superior central incisor crown supported by implant was modeled and three different placement conditions were simulated: SS - 2.0-mm-thick root dentin fragment positioned between the alveolar buccal wall and implant; heterologous bone graft (HBG) - bovine bone graft positioned the alveolar buccal wall and implant; and control (C) - implant fully placed in bone tissue of a healed alveolus. The model was restricted at the lateral surfaces of the bone tissue and the following loads were simulated: Both oblique (45°) loads of 100 N on the lingual surface of the crown (maximal habitual intercuspation) and 25.5 N on the incisal edge of the crown (tooth contact during mandibular protrusion) were simultaneously applied. Tensile stress, shear stress, compression, and displacement were analyzed in the cortical bone, trabecular bone, dentin root fragment, and bone graft; while equivalent von Mises stresses were quantified in the implant and prosthetic components. Results: Stress values of SS and HBG in the bone tissues were higher than C, while slight differences within models were observed for dentin root fragment, bone graft, implant, and prosthetic components. Conclusions: The SS technique presented the highest stress concentration in the peri-implant tissues.

5.
Environ Sci Pollut Res Int ; 30(16): 46604-46617, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36719587

RESUMO

Chemicals from anthropogenic activities such as domestic sewage, pesticide leaching, and improper chemical disposal have caused groundwater contamination. The presence of these emerging contaminants in the aquatic environment can change water quality and biota composition. Thus, this study investigates the effect of two emerging contaminants, anti-inflammatory drug diclofenac (DCF) and antibiotic sulfamethoxazole (SMX), on the aquatic environment, evaluating the phytoplankton community structure. A microcosm experiment was conducted with 16 sampling units, each one with 500 mL of water sample containing phytoplankton exposed to these drugs at different concentrations (0.1, 0.5, and 1.0 mg L-1). The experiment lasted 15 days, and samples were collected on days 0, 3, 5, 7, and 14 to evaluate the phytoplankton community, the concentrations of the drugs, and the nutrients in the samples. Six phytoplankton groups were identified, and diatoms and green algae were the most diverse and abundant groups. For the entire community, we identified differences between the days of the experiment, varying in the diversity and density of organisms, but not between the concentrations of the two drugs. Evaluating the groups separately, we identified differences in the abundance of cyanobacteria for the treatment with diclofenac and desmids for the treatment with sulfamethoxazole. We demonstrated that the presence of pharmaceuticals in freshwater ecosystems can somehow affect the phytoplankton community, especially the diversity and abundance of cyanobacteria and desmids. Therefore, our study indicates the importance of evaluating the presence of pharmaceuticals in freshwater ecosystems and their influence on aquatic organisms, as well as pharmaceuticals may be changing the structure of the aquatic environment.


Assuntos
Cianobactérias , Poluentes Químicos da Água , Diclofenaco , Fitoplâncton , Sulfametoxazol , Ecossistema , Poluentes Químicos da Água/análise , Preparações Farmacêuticas
6.
J Child Health Care ; 27(4): 547-561, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-35333628

RESUMO

To analyze the accuracy of clinical indicators of nursing diagnosis, Imbalanced nutrition: less than the body requirements in pediatric patients undergoing chemotherapy. A cross-sectional study was carried out in a pediatric oncohematology unit. A total of 123 children aged 5-18 years were evaluated. The Standards for Reporting Diagnostic Accuracy Studies (STARD) protocol was used. Latent class analysis was performed to obtain sensitivity and specificity of clinical indicators. The diagnosis was identified in six children (5.23%). The most frequent clinical indicator in the study was report of food intake less than recommended daily allowance (n = 61; 49.6%), followed by excessive hair loss (n = 49; 39.8%), misperception (n = 42; 34.1%), satiety immediately upon ingesting food (n = 32; 26%), lack of information (n = 30; 24.4%), and pale mucous membranes (n = 22; 17.9%). The 10 indicators that sensitivity and specificity were statistically superior to 50% were food intake less than recommended daily allowance, misperception, insufficient interest in food, lack of food, hyperactive bowel sounds, body weight 20% or more below ideal weight range, insufficient muscle tone, food aversion, abdominal cramping, and misinformation. The clinical indicators Food intake less than recommended daily allowance and Misperception can be considered the most important indicators for the initial inference of the diagnosis due to their high values of specificity and sensitivity. It is essential that nurses provide targeted and qualified assistance based on the signs and symptoms presented by patients, as they will be able to design appropriate interventions to obtain the desired results.


Assuntos
Estado Nutricional , Humanos , Criança , Estudos Transversais , Sensibilidade e Especificidade
7.
Braz. dent. j ; 34(6): 140-149, 2023. tab, graf
Artigo em Inglês | LILACS-Express | LILACS, BBO - odontologia (Brasil) | ID: biblio-1528038

RESUMO

Abstract This study aimed to evaluate the influence of material and crown design on the biomechanical behavior of implant-supported crowns with hybrid abutment (HA) through three-dimensional (3D) finite element analysis. The study factors were the type of material used as the mesostructure or crown (zirconia, lithium disilicate, and hybrid ceramic) and the crown design cemented to the titanium base (mesostructure cemented to the titanium base and a crown cemented on it (HaC); hybrid crown-abutment, the abutment and crown are manufactured as a single piece and cemented to the titanium base (HC); monolithic crown cemented on the titanium base and screwed to the implant (CS); and monolithic crown cemented on the titanium base (CC). Four 3D models were constructed using an implant with an internal connection, and an oblique load of 130 N was applied at 45° to the long axis of the implant. The models were evaluated using the von Mises stress for crown, abutment, screw, and implant and maximum principal stress for bone tissues. The lowest stresses occurred in the groups with a lower elastic modulus material, mainly hybrid ceramics, considered a material with greater resilience. The cemented crown group presented the lowest stress values. The stresses were concentrated in the cervical region of the crown at the titanium crown/base interface. Mesostructures made of materials with a higher elastic modulus exhibited a higher concentration of stress. The presence of a screw hole increased the stress concentration in the ceramic crown. Cemented ceramic crowns exhibited better biomechanical behavior than screw-retained crowns.


Resumo O estudo teve como objetivo avaliar a influência do material e do desenho da coroa no comportamento biomecânico de coroas implanto-suportadas com pilar híbrido (AH) por meio da análise tridimensional (3D) de elementos finitos. Os fatores de estudo foram o tipo de material do HA ou coroa (zircônia, dissilicato de lítio e cerâmica híbrida) e o desenho da coroa sobre a base de titânio (mesoestrutura cimentada à base de titânio e coroa total cimentada em cerâmica; pilar e coroa fabricados em peça única cimentada à base de titânio; coroa monolítica cimentada sobre a base de titânio e aparafusada ao implante; e coroa monolítica cimentada à base de titânio). Quatro modelos 3D foram construídos e uma carga oblíqua de 130 N foi aplicada a 45° em relação ao longo eixo do dente. Os modelos foram avaliados utilizando a tensão de von Mises para a coroa, pilar, parafuso, implante e tensão principal máxima (tensão de tração) para o tecido ósseo. As menores tensões ocorreram nos grupos que apresentaram um material com menor módulo de elasticidade, principalmente a cerâmica híbrida, considerada um material com maior resiliência. Com relação às diferentes configurações, o modelo com coroa cimentada apresentou os menores valores de tensão. As tensões foram concentradas na região cervical da coroa na interface entre coroa e base de titânio. Mesoestruturas feitas de materiais com maior módulo de elasticidade exibiram maior concentração de tensões. A presença de um orifício para parafuso aumentou a concentração de tensão na coroa de cerâmica. As coroas cerâmicas cimentadas exibiram melhor comportamento biomecânico do que as coroas parafusadas.

8.
J Prosthet Dent ; 2022 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-35705432

RESUMO

STATEMENT OF PROBLEM: Information on the survival and mode of failure of endodontically treated incisors without a ferrule and restored without dowels is lacking. PURPOSE: The purpose of this in vitro study was to compare the survival and failure mode of endodontically treated incisors without a ferrule and restored with bonded ceramic crowns and various composite resin foundation restorations without dowels with a control group with fiber dowels. MATERIAL AND METHODS: Forty-five decoronated endodontically treated bovine incisors without ferrule were divided into 3 experimental groups and restored with different adhesive foundation restorations without dowel: nanohybrid composite resin (Nd), bulk-fill composite resin foundation restoration (NdB), and fiber-reinforced bulk-fill composite resin (NdFR). A control group with conventional foundation restorations (glass-fiber dowel with nanohybrid composite resin foundation restoration without ferrule) (D) was included for comparison. All teeth were prepared to receive bonded lithium disilicate ceramic crowns luted with dual-polymerizing composite resin cement and were subjected to accelerated fatigue testing. Cyclic isometric loading was applied to the incisal edge at an angle of 30 degrees and a frequency of 5 Hz, beginning with a load of 100 N (5000 cycles). A 100-N load increase was applied each 15 000 cycles. Specimens were loaded until failure or to a maximum for cycles endured of 1000 N (140 000 cycles). Groups were compared by using the Kaplan-Meier survival analysis (log rank test at α=.05 and pairwise post hoc comparisons) and life table analysis for load-at-failure (followed by Wilcoxon pairwise comparison α=.05). RESULTS: All the specimens failed before 140 000 load cycles. Even though no statistically significant differences were found between the experimental groups without dowel (P>.127), the fiber-reinforced foundation restoration yielded the highest mean ±standard deviation cycles to failure (46 023 ±4326) compared with Nd (38 899 ±2975) and NdB (39 751 ±2998). NdFR, however, outperformed the foundation restoration with glass-fiber dowel (35 026 ±2687) (P<.05). Most failure in groups without dowel were restorable, while 100% of catastrophic failure (unrestorable) were found in the group with dowels. CONCLUSIONS: Based on the present in vitro study, dowels did not improve the performance of the adhesive restoration of endodontically treated incisors without a ferrule. The use of a short fiber-reinforced composite resin foundation restoration without a dowel was able to not only improve the resistance of the restorations compared with adhesive foundation restorations with dowels but also minimize catastrophic failures.

9.
Int J Esthet Dent ; 16(4): 534-552, 2021 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-34694078

RESUMO

PURPOSE: The present study aimed to investigate the resistance and failure mode of broken-down endodontically treated incisors without ferrule restored with CAD/CAM endocrowns. MATERIALS AND METHODS: Endodontically treated bovine incisors (N = 30) without ferrule were divided into two groups and restored with two types of CAD/CAM endocrowns: lithium disilicate (Eld) or resin nanoceramics (Erc). The preparations included a 4-mm-deep 'internal ferrule' and immediate dentin sealing. The samples were subjected to accelerated fatigue testing. Cyclic isometric loading was applied to the incisal edge at a 30-degree angle at a frequency of 5 Hz, beginning with a load of 100 N (5,000 cycles). A 100 N load increase was applied every 15,000 cycles. Specimens were loaded until failure or to a maximum of 140,000 cycles. Previously published data from the same authors regarding lithium disilicate crowns over post-and-core buildups without ferrule (NfPf), core buildups without post without ferrule (NfNpFR), and with a 2-mm ferrule (FNp) using the same experimental setup were included for comparison. Groups were compared using the Kaplan Meier survival analysis for cycles (log rank pairwise post hoc test comparisons at P = 0.05) and Life Table survival analysis for load at failure, followed by the Wilcoxon pairwise comparison at P = 0.05. RESULTS: All specimens failed before 140,000 load cycles. There was no statistically significant difference between the endocrown materials (Eld: 53,448 mean endured cycles; Erc: 52,397 mean endured cycles; P = 0.844). Endocrowns outperformed the group with lithium disilicate crowns on incisors without ferrule and post-and-core buildup (NfPf with mean endured 35,025 cycles), showed no statistical difference compared with the group with no-post fiber-reinforced composite resin core buildup (NfNpFR with 45,557 mean endured cycles), and had a lower survival rate compared with the group with ferrule (FNp with mean endured 73,244 cycles). Endocrowns generated a majority of non-catastrophic failures (with an advantage for Erc), while 100% of catastrophic failures were found in the group with a post. CONCLUSIONS: CAD/CAM endocrowns of nonvital incisors without ferrule improved the resistance and optimized the failure mode when compared with traditional bonded crowns with adhesive post-and-core and no-post buildups.


Assuntos
Técnica para Retentor Intrarradicular , Dente não Vital , Animais , Bovinos , Resinas Compostas , Desenho Assistido por Computador , Coroas , Falha de Restauração Dentária , Análise do Estresse Dentário , Humanos , Incisivo , Teste de Materiais , Dente não Vital/terapia
10.
Environ Manage ; 68(4): 445-452, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34341867

RESUMO

The Tocantins-Araguaia Basin is one of the largest river systems in South America, located entirely within Brazilian territory. In the last decades, capital-concentrating activities such as agribusiness, mining, and hydropower promoted extensive changes in land cover, hydrology, and environmental conditions. These changes are jeopardizing the basin's biodiversity and ecosystem services. Threats are escalating as poor environmental policies continue to be formulated, such as environmentally unsustainable hydropower plants, large-scale agriculture for commodity production, and aquaculture with non-native fish. If the current model persists, it will deepen the environmental crisis in the basin, compromising broad conservation goals and social development in the long term. Better policies will require thought and planning to minimize growing threats and ensure the basin's sustainability for future generations.


Assuntos
Ecossistema , Rios , Animais , Biodiversidade , Conservação dos Recursos Naturais , Política Ambiental
11.
Comput Methods Programs Biomed ; 207: 106195, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34082308

RESUMO

BACKGROUND AND OBJECTIVES: Differences in dental maturation may affect the prognosis and clinical management of traumatized teeth. However, evaluation of the outcomes of dental trauma to the tooth and support structures in an in vivo model involves major methodological and ethical implications. Thus, the aim of the present study was to perform a three-dimensional finite element analysis of permanent maxillary central incisors in different stages of root development under different trauma settings. METHODS: The study factors included two trauma conditions (B, buccal; I, incisal) on upper permanent central incisors showing three different stages of root development (CR, complete rhizogenesis; IRA; incomplete rhizogenesis in the apical third of the root; and IRM, incomplete rhizogenesis in the middle third of the root) to yield six models. The complete rhizogenesis model was obtained with a cone-beam computed tomography examination of an extracted tooth. The two incomplete rhizogenesis models were modeled on the basis of similar examinations of patients. Trauma was simulated by applying a 300 N static surface to surface load on the incisal edge or perpendicular to the buccal surface of the tooth. The displacement and equivalent von Mises (σvM) stress values were obtained for alveolar bone, periodontal ligament, apical papilla, and dentin for the quantitative analysis. A σvM color-coded scale was used for qualitative analysis. RESULTS: The force direction had a greater influence on the stress than the root-formation stage. Buccal forces resulted in higher stress concentration in the bone and periodontal ligament, especially in B-CR. Lower stress was found on the periodontal ligament as the root formation progressed (decrease of 8% from B-IRA to B-CR and 11% from B-IRM to B-CR). The incomplete rhizogenesis models showed higher σvM stress peak values in dentin in comparison with complete rhizogenesis (increase of 52% from B-CR to B-IRA and 56% from B-CR to B-IRM). CONCLUSIONS: Buccal forces yielded greater stress values regardless of the stage of rhizogenesis. Teeth with fully formed roots showed a higher stress concentration in the alveolar bone and periodontal ligament in comparison with immature teeth, with the latter presenting high stresses in the tooth crown.


Assuntos
Incisivo , Coroa do Dente , Análise de Elementos Finitos , Humanos , Incisivo/diagnóstico por imagem , Maxila/diagnóstico por imagem , Ligamento Periodontal/diagnóstico por imagem , Estresse Mecânico
12.
Braz Dent J ; 32(1): 34-41, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33914000

RESUMO

The objective of this study was to compare the biomechanical behavior of peri-implant bone tissue and prosthetic components in two modalities of treatment for posterior region of the maxilla, using short implants or standard-length implants associated with bone graft in the maxillary sinus. Four 3D models of a crown supported by an implant fixed in the posterior maxilla were constructed. The type of implant: short implant (S) or standard-length implant with the presence of sinus graft (L) and type of crown retention: cemented (C) or screwed (S) were the study factors. The models were divided into SC- cemented crown on a short implant; SS- screwed crown on the short implant; LC- cemented crown on a standard-length implant after bone graft in the maxillary sinus and LS- crown screwed on a standard-length implant after bone graft in the maxillary sinus. An axial occlusal loading of 300 N was applied, divided into five points (60N each) corresponding to occlusal contact. The following analysis criteria were observed: Shear Stress, Maximum and Minimum Main Stress for bone tissue and von Mises Stress for the implant and prosthetic components. The use of standard-length implants reduced the shear stress in the cortical bone by 35.75% and the medullary bone by 51% when compared to short implants. The length of the implant did not affect the stress concentration in the crown, and the cement layer acted by reducing the stresses in the ceramic veneer and framework by 42%. Standard-implants associated with cemented crowns showed better biomechanical behavior.


Assuntos
Implantes Dentários , Maxila , Coroas , Planejamento de Prótese Dentária , Prótese Dentária Fixada por Implante , Análise do Estresse Dentário , Análise de Elementos Finitos , Maxila/cirurgia , Estresse Mecânico
13.
Sci Total Environ ; 776: 145948, 2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-33647654

RESUMO

The implementation of environmental monitoring programs in areas under anthropogenic pressure is essential to investigate the processes that generate and maintain biodiversity in ecosystems and to establish the most appropriate conservation strategies according to the area. We investigated whether environmental variables or temporal scale influenced zooplankton spatial diversity and beta diversity components in the Madeira River basin (Amazon tributary, Rondônia state, Brazil) from 2009 to 2015. We also investigated the local site contribution to overall beta diversity (LCBD) and to each of its components, to be able to propose conservation strategies more suitable for the river basin. Alpha diversity values decreased over time, while total beta diversity and the abundance difference component increased. A pattern of abundance difference (Podani family) dominated spatial beta diversity within the major sampling campaigns (at each time point). Environmental variables and heterogeneity, temporal scale (sampling campaigns), and also the dam installation contributed to variation in spatial beta diversity and its components. On the other hand, the flood pulse did not influence spatial beta diversity over time. Few sites contributed significantly to beta diversity prior dam installation, but most sites contributed significantly to beta diversity values at least at one point in time, in the post-dam phase. Thus, post-damming, all sites should continue to be monitored for conservation and restoration of zooplankton communities and biodiversity preservation, as changes are likely to still occur. Analysis of beta diversity, its components, and LCBD, are useful and efficient methods to study spatio-temporal changes in communities and identify critical sites. Impoundment and environmental variation significantly affect zooplankton community beta diversity, dependent on underlying mechanisms such as substitution or abundance differences that diversify communities spatially and temporally.


Assuntos
Rios , Zooplâncton , Animais , Biodiversidade , Brasil , Ecossistema
14.
Braz. dent. j ; 32(1): 34-41, Jan.-Feb. 2021. tab, graf
Artigo em Inglês | LILACS, BBO - odontologia (Brasil) | ID: biblio-1180717

RESUMO

Abstract The objective of this study was to compare the biomechanical behavior of peri-implant bone tissue and prosthetic components in two modalities of treatment for posterior region of the maxilla, using short implants or standard-length implants associated with bone graft in the maxillary sinus. Four 3D models of a crown supported by an implant fixed in the posterior maxilla were constructed. The type of implant: short implant (S) or standard-length implant with the presence of sinus graft (L) and type of crown retention: cemented (C) or screwed (S) were the study factors. The models were divided into SC- cemented crown on a short implant; SS- screwed crown on the short implant; LC- cemented crown on a standard-length implant after bone graft in the maxillary sinus and LS- crown screwed on a standard-length implant after bone graft in the maxillary sinus. An axial occlusal loading of 300 N was applied, divided into five points (60N each) corresponding to occlusal contact. The following analysis criteria were observed: Shear Stress, Maximum and Minimum Main Stress for bone tissue and von Mises Stress for the implant and prosthetic components. The use of standard-length implants reduced the shear stress in the cortical bone by 35.75% and the medullary bone by 51% when compared to short implants. The length of the implant did not affect the stress concentration in the crown, and the cement layer acted by reducing the stresses in the ceramic veneer and framework by 42%. Standard-implants associated with cemented crowns showed better biomechanical behavior.


Resumo O objetivo do estudo foi avaliar o comportamento biomecânico do tecido ósseo peri-implantar e dos componentes protéticos em duas modalidades de tratamento para região posterior da maxila, utilizando implantes curtos ou implantes de comprimento padrão associados a enxerto ósseo em seio maxilar. Foram construídos quatro modelos 3D de uma coroa suportada por um implante osseointegrado na região posterior da maxila. O tipo de implante: implante curto (S) ou implante de comprimento padrão com presença de enxerto sinusal (L) e tipo de retenção da restauração: cimentada (C) ou parafusada (S) foram os fatores de estudo. Foi aplicada uma força oclusal de 300N, dividida em cinco pontos (60 N cada) correspondentes ao contato oclusal de um primeiro molar superior. Foram observados os seguintes critérios de análise: tensão de cisalhamento, tensão principal máxima e mínima para o tecido ósseo e tensão de Von Mises para o implante e componentes protéticos. O uso de implantes de comprimento padrão reduziu a tensão de cisalhamento no osso cortical em 35,75% e no osso medular em 51% quando comparado aos implantes curtos. O comprimento do implante não afetou a concentração de tensão na restauração. A camada de cimento atuou reduzindo as tensões na cerâmica de cobertura e infraestrutura de cerâmica em 42%. Os implantes de tamanho padrão associados às coroas cimentadas apresentaram o melhor comportamento biomecânico.


Assuntos
Implantes Dentários , Maxila/cirurgia , Estresse Mecânico , Planejamento de Prótese Dentária , Prótese Dentária Fixada por Implante , Análise de Elementos Finitos , Coroas , Análise do Estresse Dentário
15.
J Esthet Restor Dent ; 33(1): 88-98, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33404184

RESUMO

BACKGROUND: Immediate dentin sealing implies applying an adhesive system to dentin directly after tooth preparation, before impression. The technique is universal (inlays, onlays, veneers, crowns) and well documented clinically and experimentally. Different types of dentin bonding agents (DBAs) are available on the market. Major differences lie in the thickness of the hybrid layer and overlaying adhesive resin (filled vs. unfilled/lightly filled adhesives). OBJECTIVE: The objective of this work is to provide precise clinical instructions and present new experimental data about the bond strength of five DBAs (Optibond FL, Scotchbond MP, Single Bond Plus, Clearfil SE Bond, and Scotchbond Universal) used conventionally (dentin sealed at the time of restoration delivery) or with immediate dentin sealing, as well as with an additional flowable resin coating. METHODS: Seventy-five human molars were selected, restored/tested according the microtensile bond strength method. Fifteen groups (n=5) were obtained from the combination of the five DBAs and three application modes: delayed dentin sealing, immediate dentin sealing and immediate dentin sealing with flowable resin coating. RESULTS: It appears that immediate dentin sealing was confirmed to significantly improve the bond strength of all tested adhesives. The use of a flowable resin coating reinforcement after immediate dentin sealing increased the microtensile bond strength of all unfilled/lightly filled adhesives (from 233% of increase for ScotchBond MP, up to 560% for Clearfil SE Bond) and maintained the performance of the 3-step golden standard adhesive. Optibond FL used with (52.51 MPa) or without (54.75 MPa) additional flowable resin coating and Clearfil SE Bond (45.64 MPa) used with flowable resin coating provided the best results. CLINICAL SIGNIFICANCE: The original immediate dentin sealing (IDS) technique implies the use of a filled DBA. With unfilled/lightly filled adhesives, it is suggested to reinforce IDS with an additional flowable resin coating. This seems especially paramount to the performance of simplified adhesive systems to protect the thin bonding interface from oxygen inhibition and preserve IDS layer during predelivery cleaning of the preparation. The clinical reinforcement of unfilled/lightly filled IDS with flowable resin composite is encouraged for more predictable bonding.


Assuntos
Colagem Dentária , Adesivos Dentinários , Resinas Compostas , Cimentos Dentários , Dentina , Humanos , Teste de Materiais , Cimentos de Resina , Propriedades de Superfície , Resistência à Tração
16.
Braz. j. oral sci ; 19: e208910, jan.-dez. 2020. ilus
Artigo em Inglês | BBO - odontologia (Brasil), LILACS | ID: biblio-1152226

RESUMO

Aim: This study aimed the description of a protocol to acquire a 3D finite element (FE) model of a human maxillary central incisor tooth restored with ceramic crowns with enhanced geometric detail through an easy-to-use and low-cost concept and validate it through finite element analysis (FEA). Methods: A human maxillary central incisor was digitalized using a Cone Beam Computer Tomography (CBCT) scanner. The resulted tooth CBCT DICOM files were imported into a free medical imaging software (Invesalius) for 3D surface/geometric reconstruction in stereolithographic file format (STL). The STL file was exported to a computer-aided-design (CAD) software (SolidWorks), converted into a 3D solid model and edited to simulate different materials for full crown restorations. The obtained model was exported into a FEA software to evaluate the influence of different core materials (zirconia - Zr, lithium disilicate - Ds or palladium/silver - Ps) on the mechanical behavior of the restorations under a 100 N applied to the palatal surface at 135 degrees to the long axis of the tooth, followed by a load of 25.5 N perpendicular to the incisal edge of the crown. The quantitative and qualitative analysis of maximum principal stress (ceramic veneer) and maximum principal strain (core) were obtained. Results: The Zr model presented lower stress and strain concentration in the ceramic veneer and core than Ds and Ps models. For all models, the stresses were concentrated in the external surface of the veneering ceramic and strains in the internal surface of core, both near to the loading area. Conclusion: The described procedure is a quick, inexpensive and feasible protocol to obtain a highly detailed 3D FE model, and thus could be considered for future 3D FE analysis. The results of numerical simulation confirm that stiffer core materials result in a reduced stress concentration in ceramic veneer


Assuntos
Cerâmica , Análise de Elementos Finitos , Imageamento Tridimensional , Análise do Estresse Dentário
17.
ROBRAC ; 28(87): 248-251, out./dez. 2019. ilus
Artigo em Português | LILACS-Express | LILACS | ID: biblio-1096273

RESUMO

O diagnóstico e a intervenção precoce da má oclusão, possibilitam um crescimento adequado do complexo maxilo mandibular. O objetivo deste trabalho é apresentar um relato de caso clínico de um paciente em fase de dentadura mista que apresentava mordida aberta anterior e mordida cruzada posterior bilateral. Foi proposto a instalação de um disjuntor maxilar tipo Haas. Considerações finais: Após a instalação do aparelho o paciente interrompeu o hábito de sucção digital que possuía. A expansão maxilar promovida pelo expansor Haas associada à interrupção do hábito, resultaram na correção da mordida aberta e mordida cruzada posterior bilateral. Paciente faz uso de placa de Hawley para contenção há 9 meses.


Diagnosis and early intervention of malocclusion enable adequate growth of the mandibular maxillary complex. The aim of this paper is to report a case of a patient with mixed dentition who presented anterior open bite and bilateral posterior crossbite. It has been proposed to install a Haas type jaw breaker. Final considerations: After the device was installed, the patient discontinued his digital sucking habit. The maxillary expansion promoted by Haas expander associated with the interruption of the habit resulted in the correction of the open bite and bilateral posterior crossbite. Patient has been using Hawley plaque for retention for 9 months.

18.
ROBRAC ; 28(87): 260-265, out./dez. 2019. ilus
Artigo em Português | LILACS-Express | LILACS | ID: biblio-1096274

RESUMO

Objetivo: Este trabalho tem como objetivo apresentar um caso clínico de reabilitação estética anterior (centrais e laterais anterossuperiores) associando facetas e coroas cerâmicas cimentadas com diferentes técnicas (cimento resinoso e resina composta aquecida) com a finalidade de reproduzir as características dos dentes naturais. Material e Métodos: Paciente A.M.A., gênero feminino, 47 anos, compareceu à clínica odontológica da Faculdade de Odontologia da Universidade Federal de Goiás (UFG), relatando insatisfação com a estética do seu sorriso, diferenças no formato e cor de seus dentes. Ao exame clínico intrabucal verificou-se uma coroa total provisória do dente 22, e o mau posicionamento do dente 12 em relação aos adjacentes. Foi indicada cirurgia periodontal para aumento de coroa clínica, clareamento dental, duas facetas cerâmicas nos incisivos centrais e duas coroas cerâmicas nos incisivos laterais superiores. Após a cirurgia periodontal e clareamento, foi realizado o refinamento dos preparos para coroa total e preparos para faceta cerâmica. O material de escolha para as restaurações foi o dissilicato de lítio devido sua grande capacidade de mimetizar o dente natural. As coroas foram cimentadas com isolamento relativo do campo operatório e cimento resinoso dual. As facetas foram cimentadas com isolamento absoluto e resina composta aquecida. Resultados: Após 15 dias da cimentação a paciente retornou à clínica onde se observou saúde periodontal e perfeita adaptação das restaurações indiretas. Conclusão: Obteve-se excelente resultado estético associando diferentes tipos de restaurações e técnicas de cimentação adesiva e a paciente se mostrou confortável com as diferentes abordagens e satisfeita com o resultado estético do tratamento.


Objective: This study aims to present a clinical case of anterior aesthetic rehabilitation (central and anterior superior sides), combining cemented ceramic veneers and crowns with different techniques (resin cement and heated composite resin) with the use of chemical substances as used substances. Material and Methods: Patient A.M.A., female, 47 years old, compared to the dental clinic of the Faculty of Dentistry of the Federal University of Goiás (UFG), relating dissatisfaction with the aesthetics of his smile, differences in the shape and color of his patients. On intraoral clinical examination, a provisional total crown of tooth 22 was found, and tooth 12 was poorly positioned in relation to adjacent teeth. Periodontal surgery was indicated to increase the clinical crown, tooth whitening, two ceramic veneers on the central incisors and two ceramic crowns on the upper lateral incisors. After periodontal surgery and whitening, the preparations for the full crown and preparations for the ceramic veneer were refined. The material of choice for restorations was dissolved on the site due to its great ability to mimic the natural tooth. As crowns, they were cemented with isolation relative to the operative field and double resin cement. The veneers were cemented with absolute insulation and heated composite resin. Results: After 15 days of cementation, the patient returned to the clinic where he recovered from periodontal health and perfect adaptation of the indirect restorations. Conclusion: You get an excellent aesthetic result by associating different types of restorations and adhesive cementation techniques and a patient is comfortable with different approaches and satisfaction with the aesthetic result of the treatment.

19.
Einstein (Sao Paulo) ; 17(2): eAO4405, 2019 Apr 08.
Artigo em Inglês, Português | MEDLINE | ID: mdl-30970045

RESUMO

OBJECTIVE: To prepare an instrument to evaluate health literacy with regard to adherence to drug treatment among diabetics, identify the validity of its content, and estimate its reliability. METHODS: Pilot study, with the following stages of instrument construction: literature review, content validation, reliability estimation (internal consistency/Cronbach's alpha and reproducibility/Kappa). RESULTS: The validity of content was completed and presented alpha=0.77 and Kappa values ranged from 0.31 to 1.00. CONCLUSION: The instrument was approved regarding content validity, presented acceptable internal consistency and reproducibility. However, when applied, measurement errors it can produce must be considered.


Assuntos
Diabetes Mellitus/tratamento farmacológico , Letramento em Saúde/métodos , Letramento em Saúde/normas , Adesão à Medicação , Inquéritos e Questionários/normas , Adulto , Fatores Etários , Idoso , Brasil , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Psicometria , Valores de Referência , Reprodutibilidade dos Testes , Fatores Sexuais , Fatores Socioeconômicos
20.
Einstein (Säo Paulo) ; 17(2): eAO4405, 2019. tab
Artigo em Inglês | LILACS | ID: biblio-1001912

RESUMO

ABSTRACT Objective To prepare an instrument to evaluate health literacy with regard to adherence to drug treatment among diabetics, identify the validity of its content, and estimate its reliability. Methods Pilot study, with the following stages of instrument construction: literature review, content validation, reliability estimation (internal consistency/Cronbach's alpha and reproducibility/Kappa). Results The validity of content was completed and presented alpha=0.77 and Kappa values ranged from 0.31 to 1.00. Conclusion The instrument was approved regarding content validity, presented acceptable internal consistency and reproducibility. However, when applied, measurement errors it can produce must be considered.


RESUMO Objetivo Elaborar um instrumento para avaliar a alfabetização em saúde relacionada à adesão medicamentosa entre diabéticos, identificar a validade de seu conteúdo e estimar sua confiabilidade. Métodos Estudo piloto, cujas etapas de construção do instrumento foram revisão de literatura, validação de conteúdo e estimativa da confiabilidade (consistência interna/alfa de Cronbach e reprodutibilidade/Kappa). Resultados A validade de conteúdo foi concluída e apresentou valor de alfa=0,77 e o Kappa variou de 0,31 a 1,00. Conclusão O instrumento foi aprovado quanto à validade de conteúdo, apresentou consistência interna e reprodutibilidade aceitáveis. No entanto, ao ser utilizado, devem ser considerados os erros de medida que ele pode produzir.


Assuntos
Humanos , Masculino , Feminino , Adulto , Idoso , Inquéritos e Questionários/normas , Diabetes Mellitus/tratamento farmacológico , Adesão à Medicação , Letramento em Saúde/métodos , Letramento em Saúde/normas , Psicometria , Valores de Referência , Fatores Socioeconômicos , Brasil , Projetos Piloto , Fatores Sexuais , Reprodutibilidade dos Testes , Fatores Etários , Pessoa de Meia-Idade
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