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1.
Histochem Cell Biol ; 156(6): 583-594, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34476549

RESUMO

Orthosis immobilisations are routinely used in orthopaedic procedures. This intervention is applicable in bone fractures, ligament injuries, and tendonitis, among other disorders of the musculoskeletal system. We aimed to evaluate the effects of ankle joint functional immobilisation on muscle fibre morphology, connective tissue, muscle spindle and fibre typification triggered by a novel metallic orthosis. We developed a rodent-proof experimental orthosis able to hold the tibiotalar joint in a functional position for short and long terms. The tibialis anterior muscles of free and immobilised legs were collected and stained by histology and histochemistry techniques to investigate general muscle morphology, connective tissue and muscle fibre typification. Morphometric analysis of muscle cross-section area, fibre type cross-section area, fibre type density, percentage of intramuscular connective tissue, and thickness of the muscle spindle capsule were obtained to gain insights into the experimental protocol. We found that short- and long-term immobilisation decreased the cross-section area of the muscles and induced centralisation of myonuclei. The connective tissue of immobilised muscle increased after 2 and 4 weeks mainly by deposition of type III and type I collagen fibres in the perimysium and endomysium, respectively, in addition to muscle spindle capsule thickening. Type IIB muscle fibre was severely affected in our study; the profile assumed odd shapes, and our data suggest interconversion of these fibre types within long-term immobilisation. In conclusion, our protocol has produced structural and histochemical changes in muscle biology. This method might be applied to various rodent models that enable genetic manipulation for the investigation of muscle degeneration/regeneration processes.


Assuntos
Tecido Conjuntivo/metabolismo , Fibras Musculares Esqueléticas/metabolismo , Fusos Musculares/metabolismo , Animais , Articulação do Tornozelo , Histocitoquímica , Masculino , Fibras Musculares Esqueléticas/citologia , Fusos Musculares/citologia , Ratos , Ratos Wistar
2.
J Prosthet Dent ; 123(2): 232-235, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31227243

RESUMO

Digital workflow is an important tool in the development of intraoral appliances by additive manufacturing. The purpose of this article is to present a completely digital workflow that uses a free software program and a low-cost 3D printer to fabricate occlusal devices for managing temporomandibular dysfunction. Three-dimensional images were acquired of an open maxillomandibular relationship record by using a scanner. A free software program was used to design the devices, and a 3D printer was used to produce the appliances by using a biocompatible resin. An evaluation of the technique on 5 patients showed good internal fit of the 3D-printed device with a similar need for occlusal adjustment as conventionally fabricated occlusal devices.


Assuntos
Impressão Tridimensional , Transtornos da Articulação Temporomandibular , Desenho Assistido por Computador , Humanos , Software , Fluxo de Trabalho
3.
J Esthet Restor Dent ; 28(4): 208-20, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27312653

RESUMO

OBJECTIVE: The aim of this review was to update the literature with regard to the digital methods available by CEREC Chairside system to register and design the occlusion, to report their efficacy and technical innovations in the field of Restorative Dentistry. A search strategy was performed using the key-words: "virtual articulator," or "CAD-CAM and occlusal recording," or "CAD-CAM and occlusion register," or "CAD-CAM and occlusal contacts," or "CAD-CAM and prosthesis." MATERIAL AND METHODS: Inclusion criteria comprised studies evaluating the use of digital methods available by CEREC System for occlusal registration and design during prosthodontics treatment. PubMed and Cochrane library and reference lists were searched up to January 2016. RESULTS: The search resulted in 280 articles after removing duplicates. Subsequently, 233 records were excluded and 49 studies were selected for reading in full. Eleven articles were considered eligible for the systematic review (4 in vitro and 7 clinical studies). CONCLUSION: Scientific evidence suggests that digital methods were accurate to register and design the occlusion of dental prostheses. Nevertheless, further clinical studies are required to establish a conclusion with regard to its accuracy in prosthodontics treatment. CLINICAL SIGNIFICANCE: Digital technologies allow the design of occlusal surfaces of CAD-CAM fabricated prostheses using innovative approaches. This systematic review aimed to update the literature to help dentists determine the most appropriate digital method to register and design the occlusal surface of CAD-CAM crowns. (J Esthet Restor Dent 28:208-220, 2016).


Assuntos
Oclusão Dentária , Restauração Dentária Permanente , Sistemas Automatizados de Assistência Junto ao Leito , Desenho Assistido por Computador , Humanos
4.
Sci Rep ; 9(1): 18403, 2019 12 05.
Artigo em Inglês | MEDLINE | ID: mdl-31804540

RESUMO

The temporomandibular muscle dysfunction is characterized by myofascial pain and is more prevalent in women of reproductive age. Sex steroid hormones are hypothetically involved in the dysfunction, but few are the studies of steroid receptors in masticatory and mastication-related muscles. Our aim was to determine estrogen and testosterone receptor expression in rat masticatory and mastication-related muscles within the context of age and gender. Twelve rats were equally divided into four groups: (a) 10-month-old females; (b) 10-month-old males; (c) 24-month-old females; and (d) 24-month-old males. Euthanasia of the females was performed in the proestrous phase (vaginal smears) and the masticatory and accessory muscles were removed for immunohistochemical analysis. Statistical analysis was performed with ANOVA and the Tukey test. Estrogen receptor expression was similarly low in all muscles and groups. Testosterone receptor expression in the Masseter muscle of the 24-month-old male rats was higher than that in the other groups and significantly superior to its expression in the Posterior Digastric muscle. In short, testosterone receptor expression was highest in old male rats. If we generalize to humans, this fact could indicate age- and sex-related hormonal influence on temporomandibular muscle dysfunction. Further studies, however, are necessary to strengthen this hypothesis.


Assuntos
Envelhecimento/genética , Músculos da Mastigação/metabolismo , Receptores Androgênicos/genética , Receptores de Estrogênio/genética , Animais , Estrogênios/sangue , Feminino , Regulação da Expressão Gênica no Desenvolvimento , Masculino , Mastigação/fisiologia , Músculos da Mastigação/crescimento & desenvolvimento , Proestro/fisiologia , Ratos , Ratos Wistar , Receptores Androgênicos/metabolismo , Receptores de Estrogênio/metabolismo , Transdução de Sinais , Testosterona/sangue
5.
Braz Dent J ; 26(5): 458-62, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26647928

RESUMO

Since the dental implant/abutment interface cannot totally seal the passage of microorganisms, the interior of implant becomes a reservoir of pathogenic microorganisms that produce and maintain chronic inflammation in the tissues around implants. Silver nanoparticles (nano-Ag) are potent and broad-spectrum antimicrobial agents. The aim of this study was to evaluate the capacity of the nano-Ag to prevent the contamination of the implant internal surface by Candida albicans, caused by the implant/abutment microgap infiltration. Thirty-six implants were used in this experiment. Three study groups were performed: experimental group (implants receiving an application of nano-Ag in their inner cavity before installation of the abutment); positive-control group (implants receiving sterile phosphate buffer saline application instead of nano-Ag) and negative-control group (implants receiving the application of nano-Ag in the inner cavity and immersed in a sterile medium). In the positive-control and experimental groups, the implants were immersed in a Candida albicans suspension. The abutments of all three groups were screwed with a 10 N torque. After 72 h of immersion inC. albicans suspension or sterile medium, the abutments were removed and the inner surface of the implants was sampled with absorbent paper cone for fungal detection. No C. albicans contamination was observed in the negative-control group. The positive-control group showed statistically higher values of colony forming units (CFUs) of C. albicans compared with the experimental group. In conclusion, silver nanoparticles reduced C. albicans colonization inside the implants, even with low torque screw abutment.


Assuntos
Candida albicans/isolamento & purificação , Implantes Dentários , Nanopartículas Metálicas , Prata/química , Dente Suporte , Técnicas In Vitro
6.
Int J Biomater ; 2015: 485275, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25667594

RESUMO

Silver has been used in medicine for centuries because of its antimicrobial properties. More recently, silver nanoparticles have been synthesized and incorporated into several biomaterials, since their small size provides great antimicrobial effect, at low filler level. Hence, these nanoparticles have been applied in dentistry, in order to prevent or reduce biofilm formation over dental materials surfaces. This review aims to discuss the current progress in this field, highlighting aspects regarding silver nanoparticles incorporation, such as antimicrobial potential, mechanical properties, cytotoxicity, and long-term effectiveness. We also emphasize the need for more studies to determine the optimal concentration of silver nanoparticle and its release over time.

7.
J Clin Pediatr Dent ; 27(4): 339-46, 2003.
Artigo em Inglês | MEDLINE | ID: mdl-12924734

RESUMO

Since there is a lack of standardization of occlusal contacts for deciduous dentition, this study assessed distribution and different types of occlusal contacts at maximal intercuspal position in children from 4 to 5 1/2 years, with normal occlusion, finding a pattern able to be used as a reference for dentists during the rehabilitation of these children, and suitable for development of the craniofacial complex.


Assuntos
Oclusão Dentária Central , Dente Decíduo/anatomia & histologia , Pré-Escolar , Dente Canino/anatomia & histologia , Feminino , Humanos , Incisivo/anatomia & histologia , Registro da Relação Maxilomandibular , Masculino , Modelos Dentários , Dente Molar/anatomia & histologia , Coroa do Dente/anatomia & histologia
8.
J Oral Maxillofac Res ; 3(4): e3, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24422021

RESUMO

OBJECTIVES: The purpose of the present study was to translate and perform a cross-cultural adaptation of Manchester Orofacial Pain Disability Scale to the Portuguese language. MATERIAL AND METHODS: A synthesis of two independent translations done by bilingual translators whose mother tongue was the Portuguese language began the process of translation. From the synthesis of the translated version and totally blind to the original version, two different non-native English language teachers without dental knowledge translated the questionnaire back to English. The pre-final version was done by an Expert committee: the researchers, two other non-native English language teachers and one native English language speaker. The new questionnaire was then piloted among 8 patients from the target setting that were interviewed to probe it on their perceived meaning of each question. The Manchester Orofacial Pain Disability Scale (MOPDS) thus translated was called Brasil-MOPDS and was validated in 50 patients with Orofacial pain from TMJ and Occlusion clinic ambulatory of São Paulo University School of Dentistry. The Brasil-MOPDS was administered twice by an interviewer (15 - 20 day interval) and once by a second independent interviewer. The Brazilian version of the short form oral health impact profile (OHIP-14) questionnaire and the visual analogue pain scale (VAS) were applied on the same day. RESULTS: Internal consistency (Cronbach's α = 0.9), inter-observer (ICC = 0.92) and intra-observer (ICC = 0.98) correlations presented high scores. Validity of Brasil-MOPDS compared to OHIP-14 (r = 0.85) and VAS (r = 0.75) shown high correlations. CONCLUSIONS: Brasil-MOPDS was successfully translated and adapted to be applied to Brazilian patients, with satisfactory internal and external reliability.

9.
Int J Pediatr Otorhinolaryngol ; 77(4): 519-24, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23312530

RESUMO

OBJECTIVES: To compare the prevalence of signs and symptoms of temporomandibular dysfunction (TMD) in female adolescent athletes and non-athletes and to examine the association between signs and symptoms of TMD in female adolescents in different Tanner stages. METHODS: The subjects were 89 female basketball and handball players ages 10-18 years and 72 female non-athlete adolescents ages 10-19 years selected from the Department of Pediatrics (School of Medicine, Federal University of São Paulo) as a control group. A survey was used to assess the signs and symptoms of TMD. According to the answers on the survey the adolescents were classified in two categories: no signs or symptoms present (score A-absent), at least one sign or symptom present (score P-present). The ones who got score "P" were submitted to a standardized functional examination of the masticatory system by four previously calibrated examiners. Pubertal status was assessed based on physical examination by physicians from our Division. The adolescents were classified according to Tanner stages into three subgroups: subgroup 1 (before the growth spurt), subgroup 2 (growth spurt period), subgroup 3 (end of growth spurt). Significant differences between athletes and non-athletes were assessed for categorical variables (Chi-square and Fisher's exact test) and for continuous variables (Mann-Whitney test). The level of significance used was 5%. There was significant agreement between raters, kappa-values (0.621-1.000) and ICC values (0.757-0.899). RESULTS: There was no significant difference between the athletes and non-athletes in exhibiting at least one sign or symptom of TMD (p=0.301). When comparing the adolescents who presented at least one symptom of TMD to the different subgroups of Tanner stages no statistically significant differences were found (p=0.124). CONCLUSION: The lack of significant differences among female adolescent athletes and non-athletes and among the subgroups of Tanner stages may suggests that although contact sports increase the risk of temporomandibular joint lesions and estrogen levels are risk factor for onset of TMD, they do not impact significantly on the onset of this disorder, when considered alone.


Assuntos
Atletas , Transtornos da Articulação Temporomandibular/diagnóstico , Transtornos da Articulação Temporomandibular/epidemiologia , Articulação Temporomandibular/fisiopatologia , Adolescente , Criança , Feminino , Inquéritos Epidemiológicos , Humanos , Prevalência , Puberdade , Fatores de Risco , Adulto Jovem
10.
J Prosthodont Res ; 57(4): 298-303, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24128391

RESUMO

PATIENTS: Six women, with ages ranging from 52 to 64 years old, clinically evaluated (Research Diagnostic Criteria for Temporomandibular Disorders) by a single examiner were submitted to MRI (3.0 T). They had only arthralgia diagnosis. The images were evaluated by two radiologists who were not informed about the patients' clinical conditions, in which discs displacements, osteophytes and morphological irregularities, as well as completely normal images, i.e., without any characteristics were identified. DISCUSSION: TMJ arthralgia can be caused by various conditions, few of which are objectively observed when investigating its causes or diagnose temporomandibular disorders (TMD). In some cases, imaging exams can detect some conditions and magnetic resonance imaging (MRI) is commonly used for this purpose. Here, the MRI (3.0 T) enabled a detailed visualization of the structures of the TMJ, allowing the characterization of the symptomology in some cases. Despite, some images were completely normal. CONCLUSION: This case report detected some features seen on the MRI that justified a clinical diagnosis arthralgia, not associated with other clinical diagnosis. However, the detailed clinical examination should be sovereign even in the face of equipment with advanced technology.


Assuntos
Artralgia/diagnóstico , Imageamento por Ressonância Magnética/instrumentação , Articulação Temporomandibular , Idoso , Artralgia/etiologia , Artralgia/patologia , Feminino , Humanos , Imageamento por Ressonância Magnética/métodos , Pessoa de Meia-Idade , Articulação Temporomandibular/patologia
11.
Braz Dent J ; 23(5): 502-7, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23306225

RESUMO

The present study evaluated the interchangeability of prosthetic components for external hexagon implants by measuring the precision of the implant/abutment (I/A) interface with scanning electron microscopy. Ten implants for each of three brands (SIN, Conexão, Neodent) were tested with their respective abutments (milled CoCr collar rotational and non-rotational) and another of an alternative manufacturer (Microplant) in randomly arranged I/A combinations. The degree of interchangeability between the various brands of components was defined using the original abutment interface gap with its respective implant as the benchmark dimension. Accordingly, when the result for a given component placed on an implant was equal to or smaller then that gap measured when the original component of the same brand as the implant was positioned, interchangeability was considered valid. Data were compared with the Kruskal-Wallis test at 5% significance level. Some degree of misfit was observed in all specimens. Generally, the non-rotational component was more accurate than its rotational counterpart. The latter samples ranged from 0.6-16.9 µm, with a 4.6 µm median; and the former from 0.3-12.9 µm, with a 3.4 µm median. Specimens with the abutment and fixture from Conexão had larger microgap than the original set for SIN and Neodent (p<0.05). Even though the latter systems had similar results with their respective components, their interchanged abutments did not reproduce the original accuracy. The results suggest that the alternative brand abutment would have compatibility with all systems while the other brands were not completely interchangeable.


Assuntos
Ligas de Cromo/química , Projeto do Implante Dentário-Pivô/métodos , Implantes Dentários/normas , Ajuste de Prótese/métodos , Projeto do Implante Dentário-Pivô/instrumentação , Microscopia Eletrônica de Varredura
12.
Comput Methods Programs Biomed ; 104(2): 292-9, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-21531473

RESUMO

The purpose of this study was to compare the results of different hierarchical models in engineering analysis applied to dentistry with 2D and 3D models of a tooth and its supporting structures under 100 N occlusal loading at 45° and examine the reliability of simplified 2D models in dental research. Five models were built from computed-tomography scans: four 2D models with Plane Strain and Plane Stress State with linear triangular and quadratic quadrilateral elements and one 3D model. The finite element results indicated that the stress distribution was similar qualitatively in all models but the stress magnitude was quite different. It was concluded that 2D models are acceptable when investigating the biomechanical behavior of upper central incisor qualitatively. However, quantitative stress analysis is less reliable in 2D-finite element analysis, because 2D models overestimate the results and do not represent the complex anatomical configuration of dental structures. Therefore 3D finite element analyses of dental biomechanics cannot be simplified.


Assuntos
Análise de Elementos Finitos , Incisivo/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Humanos
13.
J Biomech ; 43(4): 680-6, 2010 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-19914621

RESUMO

The purpose of this work was the force-displacement response analysis of the masticatory process in a dried human skull by Double-Exposure Photorefractive Holographic Interferometry Technique (2E-PRHI). The load concentration and dissipation of the forces from dried human skull were analysed at applied loading stands as a Simulation of Isolated Contraction (SIC) of some mastication muscles. The 2EHI and Fringe Analysis Method were used to obtain the quantitative results of this force-displacement response. These results document quantitatively the real biomechanical response from dried human skull under applied loading and it can be used for complementary study by finite element model and others analysis type.


Assuntos
Força de Mordida , Análise do Estresse Dentário/instrumentação , Holografia/instrumentação , Interferometria/instrumentação , Mastigação/fisiologia , Músculos da Mastigação/fisiologia , Refratometria/instrumentação , Cadáver , Simulação por Computador , Análise do Estresse Dentário/métodos , Desenho de Equipamento , Análise de Falha de Equipamento , Humanos , Modelos Biológicos , Contração Muscular/fisiologia , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
14.
Braz. dent. j ; 26(5): 458-462, Oct. 2015. graf
Artigo em Inglês | LILACS | ID: lil-767624

RESUMO

Abstract: Since the dental implant/abutment interface cannot totally seal the passage of microorganisms, the interior of implant becomes a reservoir of pathogenic microorganisms that produce and maintain chronic inflammation in the tissues around implants. Silver nanoparticles (nano-Ag) are potent and broad-spectrum antimicrobial agents. The aim of this study was to evaluate the capacity of the nano-Ag to prevent the contamination of the implant internal surface byCandida albicans, caused by the implant/abutment microgap infiltration. Thirty-six implants were used in this experiment. Three study groups were performed: experimental group (implants receiving an application of nano-Ag in their inner cavity before installation of the abutment); positive-control group (implants receiving sterile phosphate buffer saline application instead of nano-Ag) and negative-control group (implants receiving the application of nano-Ag in the inner cavity and immersed in a sterile medium). In the positive-control and experimental groups, the implants were immersed in a Candida albicans suspension. The abutments of all three groups were screwed with a 10 N torque. After 72 h of immersion inC. albicans suspension or sterile medium, the abutments were removed and the inner surface of the implants was sampled with absorbent paper cone for fungal detection. No C. albicans contamination was observed in the negative-control group. The positive-control group showed statistically higher values of colony forming units (CFUs) of C. albicans compared with the experimental group. In conclusion, silver nanoparticles reduced C. albicans colonization inside the implants, even with low torque screw abutment.


Resumo: A interface implante/pilar não pode ser totalmente selada para passagem de microrganismos, com isso o interior do implante torna-se um reservatório de microrganismos patogênicos que promovem e mantêm a inflamação crônica nos tecidos em volta dos implantes. Nanopartículas de prata são agentes antimicrobianos potentes e de amplo espectro. O objetivo deste estudo foi avaliar a capacidade das nanopartículas de prata em evitar a contaminação porCandida albicans do interior de implantes, originada da infiltração do fungo através da interface implante/pilar. 36 implantes foram utilizados neste experimento. Três grupos de estudo foram estabelecidos: grupo experimental (os implantes receberam aplicação de nanopartículas de prata na sua cavidade interna, antes da instalação do pilar); grupo controle positivo (os implantes receberam PBS estéril em vez das nanopartículas de prata) e grupo controle negativo (implantes receberam aplicação de nanopartículas de prata na cavidade interna, mas os implantes foram imersos em meio estéril). Nos grupos controle positivo e experimental, os implantes foram imersos em suspensão deCandida albicans. Os pilares protéticos de todos os grupos foram parafusados com torque de 10 N. Após 72 h imersos na suspensão deC. albicans ou em meio estéril, os pilares foram removidos e amostras da superfície interna dos implantes foram coletadas com cone de papel absorvente para a detecção de Candida. No grupo controle negativo não foi observada contaminação por C. albicans. O grupo-controle positivo mostrou valores de unidades formadoras de colônia deCandida estatisticamente maiores quando comparado com o grupo experimental. Conclui-se que nanopartículas de prata reduzem a colonização de C. albicans dentro dos implantes, mesmo quando o pilar é parafusado com torque baixo.


Assuntos
Candida albicans/isolamento & purificação , Implantes Dentários , Nanopartículas Metálicas , Prata/química , Dente Suporte , Técnicas In Vitro
15.
Int J Pediatr Otorhinolaryngol ; 74(8): 896-900, 2010 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-20541812

RESUMO

PURPOSE: The aim of the study was to compare the prevalence of signs and symptoms of temporomandibular dysfunction (TMD) in male adolescent athletes-basketball players and non-athletes and to examine the association between signs and symptoms of TMD in male adolescents in different Tanner stages. METHODS: The subjects were 46 male basketball players ages 10-13 years and 41 male adolescent non-athletes ages 10-18 years selected from the Department of Pediatrics (School of Medicine, Federal University of São Paulo) as a control group. A questionnaire was used to assess the signs and symptoms of TMD. According to the answers on the questionnaire the adolescents were classified in two categories: no signs or symptoms present (score A-absent), at least one sign or symptom present (score P-present). The ones who got score "P" were submitted to a standardized functional examination of the masticatory system by the same examiner. Pubertal status was assessed based on physical examination by physicians from our Division. The adolescents were classified according to Tanner stages into three subgroups: subgroup 1 (before the growth spurt), subgroup 2 (growth spurt period), subgroup 3 (end of growth spurt). Significant differences between athletes and non-athletes were assessed using non-parametric Wilcoxon test for continuous variables and the Fisher's exact test for categorical variables. The level of significance used was 5%. RESULTS: There was no significant difference between the athletes and non-athletes in exhibiting at least one sign or symptom of TMD (p=0.1148). When comparing the adolescents who presented at least one symptom of TMD to the different subgroups of Tanner Stages no statistically significant differences were found (p=0.8357). CONCLUSION: The lack of significant differences among male adolescents athletes and non-athletes may be caused by the size of the sample, the age of the athletes or by a probable protective action of testosterone levels in male athletes. The lack of statistical difference comparing the adolescents who presented at least one sign or symptom of TMD to subgroups of Tanner is probably because estrogen is the risk factor hormone and the levels of estrogen in male adolescents are very low.


Assuntos
Atletas/estatística & dados numéricos , Amplitude de Movimento Articular/fisiologia , Transtornos da Articulação Temporomandibular/diagnóstico , Transtornos da Articulação Temporomandibular/epidemiologia , Adolescente , Basquetebol/fisiologia , Brasil , Criança , Estudos Transversais , Seguimentos , Humanos , Masculino , Medição da Dor , Exame Físico/métodos , Prevalência , Valores de Referência , Fatores de Risco , Índice de Gravidade de Doença , Inquéritos e Questionários
17.
Braz Oral Res ; 22(3): 270-4, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-18949315

RESUMO

Several studies have reported the benefits of sonic and/or ultrasonic instrumentation for root debridement, with most of them focusing on changes in periodontal clinical parameters. The present study investigated possible alterations in the tensile bond strength of crowns cemented with zinc phosphate cement to natural teeth after ultrasonic instrumentation. Forty recently extracted intact human third molars were selected, cleaned and stored in physiologic serum at 4 degrees C. They received standard preparations, at a 16 masculine convergence angle, and AgPd alloy crowns. The crowns were cemented with zinc phosphate cement and then divided into four groups of 10 teeth each. Each group was then subdivided into two subgroups, with one of the subgroups being submitted to 5,000 thermal cycles ranging from 55 +/- 2 to 5 +/- 2 degrees C, while the other was not. Each group was submitted to ultrasonic instrumentation for different periods of time: group 1 - 0 min (control), group 2 - 5 min, group 3 - 10 min, and group 4 - 15 min. Tensile bond strength tests were performed with an Instron testing machine (model 4310). Statistical analysis was performed using ANOVA and Tukey's test at the 5% level of significance. A significant reduction in the tensile bond strength of crowns cemented with zinc phosphate and submitted to thermal cycles was observed at 15 min (196.75 N versus 0 min = 452.01 N, 5 min = 444.23 N and 10 min = 470.85 N). Thermal cycling and ultrasonic instrumentation for 15 min caused a significant reduction in tensile bond strength (p < .05).


Assuntos
Cimentação/métodos , Tratamento do Canal Radicular/métodos , Coroa do Dente/diagnóstico por imagem , Terapia por Ultrassom/instrumentação , Cimento de Fosfato de Zinco/química , Análise de Variância , Desbridamento , Humanos , Teste de Materiais , Tratamento do Canal Radicular/instrumentação , Propriedades de Superfície , Resistência à Tração , Fatores de Tempo , Ultrassonografia
18.
Lasers Med Sci ; 22(3): 165-70, 2007 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-17235450

RESUMO

Although some studies claim to the increase of composite resin adhesion to Er:YAG-laser-treated dentin, there are still no reports on the adhesion of composite resin cements to the irradiated surface. This in vitro study evaluated the tensile bond strength (TBS) of a composite resin cement to dentin treated with the Er:YAG laser. Sixty human dentin samples were divided into four groups (n = 15): G1 (Control)-no treatment; G2-Er:YAG laser 60 mJ, 2 Hz, with water cooling, non-contact (19 J/cm(2)); G3-Er:YAG laser 60 mJ, 10 Hz, 50/10 fiber, contact, without water cooling (40 J/cm(2)); G4-Er:YAG laser 60 mJ, 10 Hz, 50/10 fiber, contact, with water cooling (40 J/cm(2)). After the surface treatment, each sample was submitted to bonding procedures. The analysis of variance (ANOVA) and Tukey tests revealed no statistical significant difference on TBS values for groups G1 (13.73 +/- 3.05 MPa), G2 (12.60 +/- 2.09 MPa) and G4 (11.17 +/- 4.04 MPa). G4 was not statistically different from G3 (8.64 +/- 2.06 MPa). Er:YAG laser irradiation with different settings can constitute an alternative tool to the use of composite resin-luting cements.


Assuntos
Resinas Compostas , Dentina/efeitos da radiação , Lasers de Estado Sólido , Humanos , Técnicas In Vitro , Resistência à Tração , Aderências Teciduais
19.
Appl Opt ; 46(22): 5419-29, 2007 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-17676158

RESUMO

Phase-shifting real-time holography with photorefractive Bi(12)SiO(20) crystal as holographic recording medium applied to load transmission evaluation and tension dissipation on a dried human skull under loading is presented. The applied loading stands as a simulation of isolated contraction (SIC) of some masticatories muscles. The four-frames phase-shifting technique and the unwrapping branch-cut technique were used to obtain the phase map. The quantitative results show the feasibility of the employed system in the study of microdisplacements in the skull structure provided by SIC.


Assuntos
Crânio/patologia , Cristalização , Desenho de Equipamento , Holografia/métodos , Humanos , Interferometria , Luz , Modelos Estatísticos , Contração Muscular , Músculos/patologia , Fatores de Tempo
20.
Braz. dent. j ; 23(5): 502-507, Sept.-Oct. 2012. ilus, graf, tab
Artigo em Inglês | LILACS | ID: lil-660351

RESUMO

The present study evaluated the interchangeability of prosthetic components for external hexagon implants by measuring the precision of the implant/abutment (I/A) interface with scanning electron microscopy. Ten implants for each of three brands (SIN, Conexão, Neodent) were tested with their respective abutments (milled CoCr collar rotational and non-rotational) and another of an alternative manufacturer (Microplant) in randomly arranged I/A combinations. The degree of interchangeability between the various brands of components was defined using the original abutment interface gap with its respective implant as the benchmark dimension. Accordingly, when the result for a given component placed on an implant was equal to or smaller then that gap measured when the original component of the same brand as the implant was positioned, interchangeability was considered valid. Data were compared with the Kruskal-Wallis test at 5% significance level. Some degree of misfit was observed in all specimens. Generally, the non-rotational component was more accurate than its rotational counterpart. The latter samples ranged from 0.6-16.9 µm, with a 4.6 µm median; and the former from 0.3-12.9 µm, with a 3.4 µm median. Specimens with the abutment and fixture from Conexão had larger microgap than the original set for SIN and Neodent (p<0.05). Even though the latter systems had similar results with their respective components, their interchanged abutments did not reproduce the original accuracy. The results suggest that the alternative brand abutment would have compatibility with all systems while the other brands were not completely interchangeable.


O presente estudo avaliou a intercambiabilidade dos componentes protéticos de implantes de hexágono externo medindo-se a precisão da interface implante/pilar com microscopia eletrônica de varredura. Foram utilizados dez implantes para cada uma de três marcas (SIN, Conexão, Neodent) com seus respectivos pilares (base metálica de CoCr , rotacional e não rotacional) e um de marca alternativa (Microplant) em um arranjo com todas as combinações de implante/pilar possíveis. O valor de referência para a intercambiabilidade das várias marcas de componentes foi definido pela diferença do pilar original para com seu respectivo implante. Dessa maneira, a intercambiabilidade foi considerada válida quando o resultado para um dado pilar colocado sobre um implante fosse igual ou menor que a diferença medida quando o pilar da mesma marca do implante fora posicionado. Os dados foram comparados pelo teste de Kruskal-Wallis com nível de significância de 5%. Um grau de desajuste foi observado em todos os espécimes. De uma maneira geral, o pilar anti-rotacional foi mais preciso do que o rotacional. Estes variaram de 0,6-16,9 µm, com mediana 4,6 µm; enquanto o anti-rotacional foi de 0,3-12,9 µm, com mediana de 3,4 µm. Os espécimes com o pilar e o implante Conexão tiveram uma diferença maior que o conjunto original para SIN e Neodent (p<0,05). Apesar destes últimos apresentarem resultados semelhantes com seus respectivos pilares, quando trocados não mantiveram a mesma precisão original. Os resultados sugerem que a marca alternativa seria a única que apresentaria compatibilidade com todos os sistemas, enquanto as outras marcas não seriam completamente intercambiáveis.


Assuntos
Ligas de Cromo/química , Projeto do Implante Dentário-Pivô/métodos , Implantes Dentários/normas , Ajuste de Prótese/métodos , Projeto do Implante Dentário-Pivô/instrumentação , Microscopia Eletrônica de Varredura
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