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1.
Int J Oral Maxillofac Implants ; 36(2): 289-294, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33909718

RESUMO

PURPOSE: The objective of this study was to evaluate the influence of the oxide layer removal procedure using acid on the roughness and internal fit of overcast universal castable long abutments (UCLAs) for a taper connection. MATERIALS AND METHODS: For this, maxillary first premolars were waxed on the plastic sleeve of 15 UCLAs with a premachined interface. The specimens were overcast using the NiCr alloy, and the frameworks were randomly distributed to undergo one of two different oxide layer removal methods: blasting with 100-µm particles of aluminum oxide at 0.60-MPa pressure or bathing for 5 hours in 0.5% hydrofluoric acid. The surface roughness was evaluated by a light interferometer at the subcritical contour of each abutment. Next, the frameworks were attached to the respective analogs for internal fit evaluation. The central cross section of each assembly was exposed, and three regions were visualized by scanning electron microscopy (SEM): taper interface, axial wall, and index region. The premachined base was used as the control. The groups were compared using analysis of variance (ANOVA) and Tukey post hoc test (α = .05). RESULTS: The results showed that acid bathing produced intermediary roughness between premachined and blasted surfaces (P < .05). SEM images showed a sealed interface at the taper region of all groups, despite some irregularities after alumina blasting. Increased discrepancies at the axial wall and index region were found after the alumina blasting procedure (P < .05). CONCLUSION: It was concluded that acid bathing should be used, instead of blasting to remove the oxide layer, to produce a better fit and smoother surface on UCLAs.


Assuntos
Dente Suporte , Óxidos , Óxido de Alumínio , Teste de Materiais , Microscopia Eletrônica de Varredura , Propriedades de Superfície
2.
J Prosthet Dent ; 125(4): 683.e1-683.e8, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33583618

RESUMO

STATEMENT OF PROBLEM: Although luting space is related to the marginal fit of indirect restorations, information on its influence on the marginal fit and tensile strength of zirconia abutments bonded to titanium bases is lacking. PURPOSE: The purpose of this in vitro study was to evaluate the influence of luting space on the marginal discrepancy and tensile strength of zirconia abutments bonded to a titanium base after dynamic loading. MATERIAL AND METHODS: Ninety implant replicas were embedded in resin blocks to attach 4-mm-high titanium luting bases. Zirconia abutments (Ceramill Zolid FX) were fabricated with different internal luting spaces: 25 µm (G25), 50 µm (G50), or 75 µm (G75). The zirconia abutments were cemented on the titanium bases by using a resin cement (Panavia F 2.0) under a constant load of 20 N. The marginal discrepancy and internal fit of 10 random specimens from each group were evaluated with a stereoscopic microscope at ×50 magnification. The remaining specimens were submitted to the tensile strength test in which half were evaluated after dynamic loading (1.2 million cycles of 200 N at 3.8 Hz) in a mechanical fatigue machine. The tensile strength test was performed using a pullout apparatus coupled to a universal testing machine at a crosshead speed of 0.5 mm/min. The mode of failure was determined by observation at ×50 magnification under a stereomicroscope and classified into adhesive or mixed. The groups were compared by using 2-way ANOVA and the Tukey HSD test (α=.05). RESULTS: Increase in the luting space did not influence the marginal discrepancy (P>.05). All zirconia abutments exhibited lower pullout strength after fatigue simulation (P<.05). G75 demonstrated lower tensile strength than G25 and G50 before and after loading (P<.05). Most failures were adhesive at the zirconia-cement interface. CONCLUSIONS: The increase of the luting space to 75 µm did not influence marginal discrepancy; however, it reduced the tensile strength of a zirconia abutment bonded to a titanium base.


Assuntos
Dente Suporte , Colagem Dentária , Análise do Estresse Dentário , Teste de Materiais , Propriedades de Superfície , Resistência à Tração , Titânio , Zircônio
3.
Rev. bras. odontol ; 77(1): 1-5, jan. 2020. ilus, tab
Artigo em Inglês | LILACS | ID: biblio-1117693

RESUMO

Objetivo: este estudo teve como objetivo comparar a resistência de união à dentina de um material à base de silicato de cálcio fotopolimerizável modificado por resina (TheraCal LC®; Bisco, Schaumburg, IL, EUA) com MTA branco (WMTA®; Angelus, Londrina, PR, Brasil). Materiais e Métodos: dezesseis incisivos superiores e caninos humanos foram selecionados e três discos de 1 mm foram obtidos a partir do terço médio de cada raiz. Na superfície coronal de cada disco, dois furos de 1,2 mm de largura foram perfurados na dentina. Em seguida, os buracos artificiais foram preenchidos com um dos materiais testados: WMTA® e TheraCal LC®. As fatias dentárias preenchidas foram armazenadas em uma solução salina tamponada com fosfato (PBS) (pH 7,2) por 7 dias a 37°C. Depois disso, a avaliação do push-out foi realizada com uma ponta do êmbolo de 1,0 mm. A carga foi aplicada a uma velocidade de 0,5 mm / min até o deslocamento do selador. Os resultados foram expressos em MPa. O teste U de Mann-Whitney foi aplicado para classificar os materiais quanto à resistência adesiva à dentina. O nível de significância foi estabelecido em = 5%. Resultados: todas as amostras apresentaram resultados de resistência de união à dentina mensuráveis e não ocorreram falhas prematuras. O TheraCal LC® demonstrou valores superiores de resistência de união à dentina quando comparado ao WMTA® (P<0,0001). Conclusões: existe uma vantagem do TheraCal LC® sobre o WMTA® no que diz respeito à resistência da união ao empurrar e, portanto, pode ser considerado um material reparador promissor e inovador


Objective: this study aimed to compare the dentin bond strength of a resin-modified light-curable calcium-silicate-based material (TheraCal LC®; Bisco, Schaumburg, IL, USA) with White MTA (WMTA®; Angelus, Londrina, PR, Brazil). Materials and Methods: sixteen human maxillary incisors and canines were selected and three 1-mm-discs were obtained from the middle third of each root. On the coronal surface of each disc, two 1.2-mm-wide-holes were drilled through the dentin. Then, artificial holes were filled with one of the tested materials: WMTA® and TheraCal LC®. The filled dental slices were stored in a phosphate-buffered saline (PBS) solution (pH 7.2) for 7 days at 37°C. After that, push-out assessment was performed with a 1.0-mm-plunger-tip. Load was applied at a crosshead speed of 0.5 mm/min until sealer displacement. The results were expressed in MPa. Mann-Whitney U test was applied to rank materials regarding dentin push-out bond strength. Significance level was set at a = 5%. Results: All specimens showed measurable results and no premature failure occurred. TheraCal LC® demonstrated superior push-out bond strength values to dentin when compared to WMTA® (P<0.0001). Conclusions: there is advantage of TheraCal LC® over WMTA® as regards to the push-out bond strength and, therefore it may be taken as a promising and innovative reparative material


Assuntos
Materiais Restauradores do Canal Radicular , Obturação do Canal Radicular , Tratamento do Canal Radicular , Cimento de Silicato , Materiais Dentários , Endodontia , Cura Luminosa de Adesivos Dentários
4.
Artigo em Inglês | MEDLINE | ID: mdl-31449582

RESUMO

Peri-implant bone remodeling occurs in all osseointegrated implants and can be defined as an adaptive process of bone around the implant in response to functional loading. This retrospective study evaluated the marginal bone remodeling around dental implants with external hexagonal connections in function for more than 10 years. The sample consisted of 17 implants placed in the posterior region of the mandible to replace one or several teeth. For all cases, the initial periapical radiograph was assessed together with a subsequent follow-up periapical radiograph. Image analysis was performed using ImageJ software to establish the initial bone measurements and subsequent bone loss. The data were statistically analyzed using paired t test at a significance level of 5%. There was significant bone remodeling when the baseline and follow-up were compared (P < .001). The mean values of peri-implant bone remodeling on the mesial aspect were 0.90 ± 0.63 mm vertically and 1.17 ± 0.60 mm horizontally. The distal aspect of the implants showed 1.01 ± 0.82 mm and 1.06 ± 0.75 mm of marginal bone remodeling vertically and horizontally, respectively. Within the limitations of this study, marginal bone remodeling was visible, and bone levels around the external hexagon implants remain stable after 10 years of function.


Assuntos
Perda do Osso Alveolar , Implantes Dentários , Remodelação Óssea , Implantação Dentária Endo-Óssea , Planejamento de Prótese Dentária , Prótese Dentária Fixada por Implante , Seguimentos , Mandíbula , Estudos Retrospectivos
5.
J Prosthodont ; 28(2): e548-e551, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29896787

RESUMO

PURPOSE: To evaluate the fracture resistance after the thermal and mechanical fatigue of feldspathic, lithium disilicate, and resin-modified CAD/CAM monolithic crowns cemented onto a universal post abutment. MATERIALS AND METHODS: A right second mandibular molar was designed in CAD/CAM software, and 30 crowns were machined using three different materials (n = 10): feldspathic ceramic, finished only with a glaze cycle (G1); lithium disilicate, sintered and finished with a glaze cycle (G2); and resin, modified by nanoceramic and finished with rubber (G3). All crowns were cemented under a constant 50 N load, the excess cement was removed, and the crowns were light-cured for 30 seconds. After being immersed in deionized water for 7 days, the crowns were submitted to thermal cycling, which consisted of varying the temperature from 2 to 50°C for 350,000 cycles, and mechanical cycling in a fatigue simulator, where a 250 N load was applied for 1,000,000 cycles at 2 Hz. The resistance of each crown was verified in a compression-to-failure test at 1 mm/min in a universal test machine. The groups were compared using one-way ANOVA with a Bonferroni post hoc test and Weibull statistics. RESULTS: The resin-modified group was the least resistant group (1755 ± 124 N), followed by the feldspathic (2147 ± 412 N) and lithium disilicate groups (2804 ± 303 N). The Weibull statistics demonstrated that lithium disilicate is the most reliable material and has the lowest fracture probability. CONCLUSIONS: It was possible to conclude that all of the tested CAD/CAM materials can be used as monolithic, implant-supported molar crowns.


Assuntos
Desenho Assistido por Computador , Coroas , Materiais Dentários/química , Falha de Restauração Dentária , Resinas Acrílicas , Silicatos de Alumínio , Porcelana Dentária , Análise do Estresse Dentário , Humanos , Técnicas In Vitro , Mandíbula , Teste de Materiais , Dente Molar , Compostos de Potássio , Propriedades de Superfície
7.
Int J Oral Maxillofac Implants ; 32(5): 1111-1115, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28906507

RESUMO

PURPOSE: The aim of this study was to evaluate the influence of the implant diameter on marginal bone remodeling around dental implants replacing single molars after a follow-up period of 3 to 6 years. MATERIALS AND METHODS: Patients who received dental implants with an external hexagon platform in healed sites to support a single metal-ceramic crown in the molar region were recalled to the office. The implantation sites and implant length information were recorded, and the implants were divided according to the implant diameter: regular (RP) or wide (WP). Each implant was assessed by digital periapical radiography, using a sensor holder for the paralleling technique. The marginal bone remodeling was determined as the distance from the implant platform to the first bone-to-implant contact, and the known implant length was used to calibrate the images in the computer software. The follow-up measurements were compared with those obtained from the radiograph taken at the time of prosthetic loading to determine the late bone remodeling. The independent t test was used to compare data. RESULTS: A total of 67 implants from 46 patients were evaluated with a mean follow-up period of 4.5 ± 1.0 years. The RP group comprised 36 implants from 29 patients (mean age: 58.3 ± 10.6 years), while 31 implants from 17 patients (mean age: 56.9 ± 11.5 years) were included in the WP group. The RP group presented lower survival rates (86.1%) than the WP group (100.0%). Similar marginal bone loss (P < .05) was identified for the RP and WP groups (1.35 ± 0.96 mm and 1.06 ± 0.70 mm, respectively). CONCLUSION: Although wide-diameter implants exhibited lower incidence failures, the bone levels were similar after the prosthetic loading around regular- and wide-diameter implants supporting single molar crowns.


Assuntos
Implantes Dentários para Um Único Dente , Implantes Dentários , Planejamento de Prótese Dentária , Dente Molar , Adulto , Idoso , Perda do Osso Alveolar/etiologia , Remodelação Óssea , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Radiografia Dentária Digital
8.
Int J Oral Maxillofac Implants ; 32(4): 858-863, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28708919

RESUMO

PURPOSE: To evaluate the influence of the collar surface topography on peri-implant marginal bone preservation. MATERIALS AND METHODS: A total of 156 patients who received at least one cylindrical implant of regular diameter with an external-hexagon platform in the posterior region of the maxilla or mandible were recalled to the office for a retrospective evaluation. Implantation sites and implant length information were recorded, and implants were divided according to the collar surface topography: machined (M) or rough (R) surface. Each implant was assessed by digital periapical radiography, using a sensor holder for the paralleling technique. The marginal bone remodeling was determined as the distance from the implant platform to the first bone-to-implant contact, and the known implant length was used to calibrate the images in the computer software. The follow-up measurements were compared with those obtained from the radiograph taken at the time of prosthetic loading to determine the late bone remodeling. An independent t test was used to compare data. RESULTS: From 138 patients who attended the recall, 242 implants (M = 126; R = 116) were evaluated with a mean follow-up period of 4.6 ± 0.9 years. Similar success rates were found in both groups (M = 95.0%; R = 95.9%). Late bone remodeling in the maxilla was not influenced by the implant collar (P = .504); however, lower marginal bone loss was observed in the R group (1.20 ± 0.52 mm) compared with the M group (1.58 ± 0.73 mm) in the mandible (P = .007). CONCLUSION: Although the implant collar design did not influence the success rate of dental implants, the rough collar design reduced the late marginal bone remodeling around external-hexagon implants in the mandible. The maxilla was not benefited by the rough collar design.


Assuntos
Perda do Osso Alveolar/prevenção & controle , Implantação Dentária Endo-Óssea/métodos , Implantes Dentários , Prótese Dentária Fixada por Implante , Mandíbula/cirurgia , Peri-Implantite/diagnóstico por imagem , Adulto , Planejamento de Prótese Dentária , Feminino , Humanos , Masculino , Maxila , Pessoa de Meia-Idade , Radiografia Dentária Digital , Estudos Retrospectivos , Propriedades de Superfície
9.
Implant Dent ; 26(3): 388-392, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28248689

RESUMO

PURPOSE: This study evaluated the microleakage at different implant-abutment (I-A) connections under unloaded and loaded conditions. MATERIALS AND METHODS: Forty implants, specially designed with an opening at the apex, were grouped according to the I-A and screw device: external hexagon implants with titanium (EH) or EH diamond-like carbon screws fixing the abutment; internal hexagon implants with titanium screws (IH); and Morse taper implants with solid (MT) or MT passing screws (MTps) abutments. The implants were fixed in a 2-compartment device, and toluidine blue solution (1.0 mg/mL) was placed at the I-A interface (upper compartment). The lower compartment was filled with purified water. Four implants of each group were loaded (50 N, 1.2 Hz) and after 50,000, 100,000, 200,000, and 300,000 cycles, aliquots were collected from the lower compartment for absorbance reading. Data were analyzed using analysis of variance for repeated measurements and Tukey (α = 0.05). RESULTS: Although microleakage increased over time in most of the groups, MTps group showed lower values when loaded (P < 0.05). The DLC on the EH screw did not prevent microleakage (P < 0.05). CONCLUSION: It can be concluded that MT connection is more effective to prevent microleakage.


Assuntos
Projeto do Implante Dentário-Pivô , Infiltração Dentária , Análise do Estresse Dentário , Diamante/química , Técnicas In Vitro , Teste de Materiais , Estresse Mecânico , Titânio/química
10.
J Endod ; 43(5): 801-804, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28292603

RESUMO

INTRODUCTION: The present study investigated the root canal dentin bond strength of 2 newly developed fast-setting mineral trioxide aggregate (MTA) and pozzolan-based cements: ENDOCEM MTA (Maruchi, Wonju, Korea) and ENDOCEM Zr (Maruchi). White MTA (Angelus, Londrina, Brazil) was used as the reference material for comparison. METHODS: Root slices (1 mm ± 0.1 mm) were obtained from the middle third of 15 maxillary incisors previously selected. Three canal-like holes (0.8 diameter) were drilled perpendicularly on the axial surface of each root slice. A standardized irrigation protocol was applied for all samples, and after drying, each hole was filled with 1 of 3 test repair materials. Finally, slices were stored in contact with phosphate-buffered saline solution (pH = 7.2) for 7 days at 37°C before the push-out assay. Data were nonparametrically evaluated at α = 5%. RESULTS: The Friedman test was unable to confirm a significant dissimilarity in push-out ranks among the tested cements (P = .220). CONCLUSIONS: The new fast-setting MTA and pozzolan-based cements ENDOCEM MTA and ENDOCEM Zr present suitable bond strength performance, which is comparable with white MTA.


Assuntos
Compostos de Alumínio/química , Compostos de Cálcio/química , Colagem Dentária , Cimentos Dentários/química , Óxidos/química , Materiais Restauradores do Canal Radicular/química , Silicatos/química , Bismuto/química , Colagem Dentária/métodos , Colagem Dentária/normas , Análise do Estresse Dentário , Combinação de Medicamentos , Humanos , Zircônio/química
11.
ImplantNewsPerio ; 1(8): 1524-1531, nov.-dez. 2016. tab
Artigo em Português | LILACS, BBO - Odontologia | ID: biblio-848536

RESUMO

Objetivo: sistematizar e organizar o conjunto de informações relacionadas ao planejamento e manejo de custos na área de Implantodontia. Material e métodos: uma reabilitação mandibular (prótese total implantorretida com carregamento imediato e ancorada por cinco implantes) foi utilizada como referência para custos. Para determinação do valor total, foram somados os honorários e os custos do profissional com o consultório, com componentes cirúrgicos e protéticos para execução do caso, além dos custos laboratoriais. O custo total foi acrescido em 20% devido à taxa de risco do tratamento. Seis marcas comerciais foram selecionadas para realização dos orçamentos. Os valores de todos os componentes em moda corrente (Reais) foram expostos baseados em um denominador comum (X). Ainda, as porcentagens de custo de cada componente segundo o tipo de cilindro selecionado também foram descritas. Resultados: o valor do tratamento conforme o sistema de implantes variou entre 64,4 X e 209,6 X. No custo fi nal, a variação ficou entre 243,1 X e 441,4 X. Conclusão: embora este trabalho não tenha englobado no custo as sessões de retorno para acompanhamento e higienização, fratura de pilares protéticos e parafusos, perda de implantes e a fratura de dentes artificiais, a maior variação nos valores do tratamento refere-se aos sistemas de implantes selecionados. Entretanto, o uso de cilindros calcináveis ou de cilindros com base metálica não interferiu significativamente no custo total, o que favorece a postura clínica de utilizar componentes com partes pré-fabricadas para aliviar os problemas biológicos na interface implante/prótese.


Objective: to organize the information related to treatment and cost management for Implant Dentistry. Material and methods: a mandibular restoration (a five implant-retained prosthesis under immediate loading) was used as reference for cost analysis. To determine the overall value, professional, surgical, prosthetic component, and laboratory costs were added. The overall cost was increased in 20% due to the treatment risk. Six different commercial manufacturers were selected to present the costs. The values in the real currency (BRL) were converted to a common denominator (X). Also, the cost percentages associated to each prosthetic cylinder were also described. Results: the overall treatment value according to each implant system ranged from 64.4 X to 209.6 X. For the overall cost, the variation was between 243.1 and 44.1 X. Conclusion: although recall sessions have not been included in this paper (e.g. hygiene maintenance, abutment screw fracture/ loosening, implant loss, and artifi cial tooth fracture events), the great cost variation relates to the choice of the dental implant system. However, the use of pre-fabricated or plastic burnout cylinders did not signifi cantly interfere in the overall cost, which favors the use of pre-fabricated parts to alleviate the biological issues at the implant-prosthesis interface.


Assuntos
Humanos , Custos e Análise de Custo , Implantes Dentários , Honorários e Preços/estatística & dados numéricos , Planejamento de Assistência ao Paciente
12.
J Endod ; 42(11): 1656-1659, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27641946

RESUMO

INTRODUCTION: The present study aimed to rank the bond strength to root dentin of a new injectable pozzolan-based root canal sealer, EndoSeal MTA, as compared with MTA Fillapex and AH Plus. METHODS: Eighteen dentinal slices (1 ± 0.1 mm) were obtained from the middle third of 6 maxillary incisors previously selected. Three canal-like holes with 0.8 mm diameter were drilled perpendicularly on the axial surface of each slice. Then, a standardized irrigation was applied for all holes that were subsequently filled with 1 of 3 test root canal sealers. After that, slices were stored in contact with phosphate-buffered saline solution (pH 7.2) for 7 days at 37°C before the push-out assay. Friedman test and Wilcoxon signed rank test with a Bonferroni correction were used to rank the results. Significance boundary was set at α = 5%. RESULTS: Friedman test confirmed a significant dissimilarity in push-out ranks among the tested cements (P < .01). Wilcoxon signed rank test demonstrated AH Plus had significant superior resistance to dislodgment compared with Endo Seal (P < .01) or MTA Fillapex (P < .01), whereas MTA Fillapex presented the lowest push-out values as compared with Endo Seal (P < .01) or AH Plus (P < .01). CONCLUSIONS: EndoSeal presents satisfactory bond strength performance for application in endodontic therapy compared with MTA Fillapex, and although it displays a new alternative of injectable bio-tight root canal sealer, it is not able to improve adhesion compared with AH Plus.


Assuntos
Cimentos para Ossos/química , Colagem Dentária , Materiais Restauradores do Canal Radicular/química , Cimento de Óxido de Zinco e Eugenol/química , Materiais Biocompatíveis/química , Compostos de Cálcio/química , Cavidade Pulpar , Dentina/química , Humanos , Irrigantes do Canal Radicular/química , Obturação do Canal Radicular/métodos , Preparo de Canal Radicular/métodos , Silicatos/química
14.
Braz Oral Res ; 30(1)2016 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-27305515

RESUMO

This study was designed to investigate the resistance to dislodgment provided by MTA HP, a new high-plasticity calcium silicate-based cement. Biodentine and White MTA Angelus were used as reference materials for comparison. Three discs 1 ± 0.1 mm thick were obtained from the middle third of the roots of 5 maxillary canines. Three 0.8-mm-wide holes were drilled on the axial surface of each root disc. Standardized irrigation was performed. Then the holes were dried with paper points and filled with one of the three tested cements. The filled dental slices were immersed in a phosphate-buffered saline (PBS) solution (pH 7.2) for 7 days before the push-out assessment. The Kruskal-Wallis test was applied to assess the effect of each endodontic cement on the push-out bond strength. Mann-Whitney with Bonferroni correction was used to isolate the differences. The alpha-type error was set at 0.05. All specimens had measurable push-out values and no premature failure occurred. There were significant differences among the materials (p <0.05). The Biodentine specimens had the highest push-out bond strength values (p < 0.05). MTA HP had significantly higher bond strength than White MTA (p < 0.05). MTA HP showed better push-out bond strength than its predecessor, White MTA; however, Biodentine had higher dislodgment resistance than both MTA formulations.


Assuntos
Compostos de Alumínio/química , Compostos de Cálcio/química , Colagem Dentária/métodos , Cimentos Dentários/química , Óxidos/química , Silicatos/química , Bismuto/química , Combinação de Medicamentos , Humanos , Teste de Materiais , Reprodutibilidade dos Testes , Materiais Restauradores do Canal Radicular/química , Preparo de Canal Radicular/métodos , Estatísticas não Paramétricas , Fatores de Tempo
15.
Arch Oral Biol ; 66: 129-40, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26945171

RESUMO

INTRODUCTION: Numerous environmental factors influence the pathogenesis of Candida biofilms and an understanding of these is necessary for appropriate clinical management. AIMS: To investigate the role of material type, pellicle and stage of biofilm development on the viability, bioactivity, virulence and structure of C. albicans biofilms. METHODS: The surface roughness (SR) and surface free energy (SFE) of acrylic and titanium discs was measured. Pellicles of saliva, or saliva supplemented with plasma, were formed on acrylic and titanium discs. Candida albicans biofilms were then generated for 1.5 h, 24h, 48 h and 72 h. The cell viability in biofilms was analysed by culture, whilst DNA concentration and the expression of Candida virulence genes (ALS1, ALS3 and HWP1) were evaluated using qPCR. Biofilm metabolic activity was determined using XTT reduction assay, and biofilm structure analysed by Scanning Electron Microscopy (SEM). RESULTS: Whilst the SR of acrylic and titanium did not significantly differ, the saliva with plasma pellicle increased significantly the total SFE of both surface. The number of viable microorganisms and DNA concentration increased with biofilm development, not differing within materials and pellicles. Biofilms developed on saliva with plasma pellicle surfaces had significantly higher activity after 24h and this was accompanied with higher expression of virulence genes at all periods. CONCLUSION: Induction of C. albicans virulence occurs with the presence of plasma proteins in pellicles, throughout biofilm growth. To mitigate such effects, reduction of increased plasmatic exudate, related to chronic inflammatory response, could aid the management of candidal biofilm-related infections.


Assuntos
Biofilmes/crescimento & desenvolvimento , Candida albicans/fisiologia , Película Dentária/microbiologia , Resinas Acrílicas/química , Biofilmes/efeitos dos fármacos , Candida albicans/citologia , Candida albicans/genética , Candida albicans/patogenicidade , Película Dentária/fisiologia , Proteínas Fúngicas/genética , Humanos , Imageamento Tridimensional , Técnicas In Vitro , Viabilidade Microbiana , Microscopia Eletrônica de Varredura , Polimetil Metacrilato/química , Distribuição Aleatória , Proteínas e Peptídeos Salivares/química , Propriedades de Superfície , Titânio/química , Virulência
16.
Artigo em Inglês | MEDLINE | ID: mdl-26249362

RESUMO

Algorithmic models have been proposed to explain adaptive behavior of bone to loading; however, these models have not been applied to explain the biomechanics of short dental implants. Purpose of present study was to simulate bone remodeling around single implants of different lengths using mechanoregulatory tissue differentiation model derived from the Stanford theory, using finite elements analysis (FEA) and to validate the theoretical prediction with the clinical findings of crestal bone loss. Loading cycles were applied on 7-, 10-, or 13-mm-long dental implants to simulate daily mastication and bone remodeling was assessed by changes in the strain energy density of bone after a 3, 6, and 12 months of function. Moreover, clinical findings of marginal bone loss in 45 patients rehabilitated with same implant designs used in the simulation (n = 15) were computed to validate the theoretical results. FEA analysis showed that although the bone density values reduced over time in the cortical bone for all groups, bone remodeling was independent of implant length. Clinical data showed a similar pattern of bone resorption compared with the data generated from mathematical analyses, independent of implant length. The results of this study showed that the mechanoregulatory tissue model could be employed in monitoring the morphological changes in bone that is subjected to biomechanical loads. In addition, the implant length did not influence the bone remodeling around single dental implants during the first year of loading.


Assuntos
Remodelação Óssea/fisiologia , Implantes Dentários , Fenômenos Biomecânicos , Densidade Óssea , Osso e Ossos/metabolismo , Planejamento de Prótese Dentária , Módulo de Elasticidade , Análise de Elementos Finitos , Humanos , Imageamento Tridimensional , Modelos Teóricos , Reprodutibilidade dos Testes
17.
J Prosthet Dent ; 115(3): 356-62, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26548870

RESUMO

STATEMENT OF PROBLEM: Whether laser-welded (LW) titanium can resist the stress corrosion produced by the combination of fluoride ions and stress in the oral environment is unknown. PURPOSE: The purpose of this in vitro study was to investigate the influence of stress corrosion on the mechanical properties of LW titanium. MATERIAL AND METHODS: Twenty-seven titanium bars (25×2 mm) with a circular cross-section were cut in half and laser-welded, while another 27 nonwelded (NW) bars were used as the control. Thirty bars were submitted to a flexural load of 480 N at 1 Hz and immersed in artificial saliva at pH 6 (S1) or in 1000 ppm fluoride-containing saliva at pH 6.0 (S2) or 2.0 (S3) at room temperature for up to 4000 cycles. After the stress corrosion simulation, the tensile strength and Vickers microhardness were determined (n=5). Twelve LW and NW bars were submitted to the corrosion immersion test media for 51 days (n=2) to determine polarization curves (n=2) in an artificial saliva media. The corroded surface was examined with scanning electron microscopy (SEM). RESULTS: The combination of fluoride and low pH significantly decreased the tensile strength of LW (P<.05). Stress corrosion did not affect the hardness of LW or NW (P>.05). NW bars immersed in S3 exhibited progressive surface dissolution, while LW bars spontaneously fractured at the welded area after 25 days of immersion in the same medium. SEM images demonstrated pitting corrosion without the presence of cracks in both groups immersed in S3. CONCLUSIONS: Stress corrosion caused by acidic fluoride-containing saliva and flexural load cycling decreased the tensile strength and hardness of LW titanium bars.


Assuntos
Corrosão , Teste de Materiais , Estresse Mecânico , Titânio/química , Lasers , Microscopia Eletrônica de Varredura , Saliva Artificial , Propriedades de Superfície
18.
Braz. oral res. (Online) ; 30(1): e84, 2016. graf
Artigo em Inglês | LILACS-Express | LILACS | ID: biblio-952007

RESUMO

Abstract This study was designed to investigate the resistance to dislodgment provided by MTA HP, a new high-plasticity calcium silicate-based cement. Biodentine and White MTA Angelus were used as reference materials for comparison. Three discs 1 ± 0.1 mm thick were obtained from the middle third of the roots of 5 maxillary canines. Three 0.8-mm-wide holes were drilled on the axial surface of each root disc. Standardized irrigation was performed. Then the holes were dried with paper points and filled with one of the three tested cements. The filled dental slices were immersed in a phosphate-buffered saline (PBS) solution (pH 7.2) for 7 days before the push-out assessment. The Kruskal-Wallis test was applied to assess the effect of each endodontic cement on the push-out bond strength. Mann-Whitney with Bonferroni correction was used to isolate the differences. The alpha-type error was set at 0.05. All specimens had measurable push-out values and no premature failure occurred. There were significant differences among the materials (p <0.05). The Biodentine specimens had the highest push-out bond strength values (p < 0.05). MTA HP had significantly higher bond strength than White MTA (p < 0.05). MTA HP showed better push-out bond strength than its predecessor, White MTA; however, Biodentine had higher dislodgment resistance than both MTA formulations.

19.
RGO (Porto Alegre) ; 63(2): 203-206, Apr.-June 2015. ilus
Artigo em Inglês | LILACS-Express | LILACS | ID: lil-755119

RESUMO

Taurodontism is the consequence of a developmental disorder in which the invagination of Hertwig's epithelial root sheath doesn't occur at a proper level. As a result, the pulp body and the chamber of a multi-root tooth, usually permanent molar teeth, are enlarged by the apical displacement of the pulp floor. Despite its clinically normal appearance, the morphological variation of this tooth can be diagnosed by a routine radiographic exam that shows enlarged apico-occlusal pulp chamber and short roots. Due to these anatomical variations, endodontic treatment of a taurodontic element is a clinical challenge given the complexity of localization and instrumentation of the root canal system. According to the degree of displacement of the pulp floor, taurodontism can be classified as: hypotaurodontism, mesotaurodontism and hypertaurodontism. This study objective is to report a clinical case of a patient who was submitted to endodontic treatment of the second inferior molar affected by hypertaurodontism.

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A taurodontia é consequência de um distúrbio de desenvolvimento em que a bainha epitelial de Hertwig não invagina corretamente em um nível normal, repercutindo em um aumento do corpo e da câmara pulpar de um dente multiradicular, predominantemente molares permanentes, pelo deslocamento do assoalho pulpar no sentido apical. Apesar de clinicamente aparentar-se como um dente normal, esta variação morfológica pode ser diagnosticada por exame radiográfico de rotina evidenciando câmara pulpar aumentadas em tamanho no sentido ápico-oclusal e raízes curtas. Devido a estas alterações anatômicas, o tratamento endodôntico de um elemento com taurodontia se torna um desafio clínico, já que é necessário um cuidado especial na localização e manejo do sistema de canais radiculares. De acordo com o grau de deslocamento apical do assoalho pulpar, a taurodontia pode ser classificada em: hipotaurodontia, mesotaurodontia e hipertaurodontia. O objetivo deste trabalho é relatar o caso clínico de um paciente que necessitou de tratamento endodôntico em um segundo molar inferior com hipertaurodontia.

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