ABSTRACT
PURPOSE: To evaluate the effect of simvastatin on relapse of tooth movement in rats using microtomography (micro CT), as well as the correlation of bone density with the orthodontic relapse. METHODS: Twenty-five adult male Wistar rats, divided into two groups, had stainless steel springs installed on left maxillary first molar. The molars were moved for 18 days, and after removing the springs, were applied by oral gavage, 5mg/kg of simvastatin in the experimental group for 20 days. Tooth relapse was assessed with a micro CT scanner, and the images chosen through the Data Viewer software 1.5.0.0 had their measurement guides made and checked by the software Image ProR plus 5.1, and compared by Mann-Whitney test. After rats were sacrificed, bone mineral density was evaluated by micro CT through the software CT Analyzer 1.13 and compared by independent T-test, as well as by Spearman correlation test. RESULTS: Relapse and bone mineral density (BMD) was lower in the experimental group than in the control group, however without a statistically significant difference. CONCLUSION: Simvastatin did not inhibit the relapse of tooth movement in rats, and there was no correlation between bone density and orthodontic relapse. .
Subject(s)
Animals , Male , Bone Density/drug effects , Hydroxymethylglutaryl-CoA Reductase Inhibitors/therapeutic use , Secondary Prevention/methods , Simvastatin/therapeutic use , Tooth Movement Techniques , Tooth Migration/prevention & control , X-Ray Microtomography/methods , Bone Remodeling/drug effects , Bone Resorption/prevention & control , Densitometry , Hydroxymethylglutaryl-CoA Reductase Inhibitors/pharmacology , Maxilla/drug effects , Maxilla/physiopathology , Rats, Wistar , Recurrence , Reproducibility of Results , Simvastatin/pharmacology , Time Factors , Treatment Outcome , Tooth Migration , Tooth Root/drug effects , Tooth Root/physiopathologyABSTRACT
Restoring flared endodontically treated teeth continues to be a challenge for clinicians. This study evaluated the effect of post types and restorative techniques on the strain, fracture resistance, and fracture mode of incisors with weakened roots. One hundred five endodontically treated bovine incisors roots (15 mm) were divided into 7 groups (n=15). The two control groups were (C) intact roots restored with Cpc (cast posts and core) or Gfp (glass fiber posts). The five experimental groups were (F) flared roots restored with GfpAp (Gfp associated with accessory glass fiber posts), GfpRc (anatomic Gfp, relined with composite resin), and GfpRcAp (anatomized Gfp with resin and accessory glass fiber posts). All teeth were restored with metal crowns. Mechanical fatigue was performed with 3x10(5)/50 N. Specimens were loaded at 45º, and the strain values (μS) were obtained on root buccal and proximal surfaces. Following that, the fracture resistance (N) was measured. One-way ANOVA and Tukey's HSD tests (α=0.05) were applied, and failure mode was checked. No significant difference in strain values among the groups was found. Cpc presented lower fracture resistance and more catastrophic failures in flared roots. Gfp associated with composite resin or accessory glass fiber posts seems to be an effective method to improve the biomechanical behavior of flared roots.
Restaurar dentes tratados endodonticamente continua sendo desafio para clínicos. Este estudo avaliou o efeito de pinos e técnicas na deformação, resistência à fratura e padrão de fratura de incisivos com canal radicular alargado. Cento e cinco raízes bovinas, tratadas endodonticamente (15 mm) foram divididas em 7 grupos (n=15). Os grupos controle (C), constituídos de raízes não alargadas, foram restauradas com Cpc (núcleo metálico fundido) ou Gfp (pino de fibra de vidro). Nos grupos experimentais os canais foram alargados (F) e restaurados com: GfpAp (Gfp associado com pinos de fibra de vidro acessórios); GfpRc (pino anatômico, reembasado com resina composta) e GfpRcAp (pino anatomizado com resina composta e pinos acessórios). Os dentes foram restaurados com coroas metálicas. Fadiga mecânica foi simulada com 3x10(5)/50 N ciclos. O teste foi realizado a 45º e a deformação (μS) obtida nas superfícies vestibular e proximal. Em seguida, a resistência à fratura (N) e o padrão de fratura foram verificados. Aplicou-se ANOVA e Teste de Tukey (α=0,05). Não houve diferença na deformação. Cpc resultou em menor resistência à fratura e com mais fraturas catastróficas em raízes fragilizadas. As técnicas de reembasamento do pino com resina composta ou o uso de pinos acessórios parecem ser efetivos para melhorar o comportamento biomecânico de raízes fragilizadas.
Subject(s)
Animals , Cattle , Dental Prosthesis Design , Incisor/physiopathology , Post and Core Technique/instrumentation , Tooth Fractures/physiopathology , Tooth Root/physiopathology , Tooth, Nonvital/therapy , Biomechanical Phenomena , Crowns , Chromium Alloys/chemistry , Composite Resins/chemistry , Dental Restoration Failure , Dental Materials/chemistry , Dental Pulp Cavity/pathology , Dental Stress Analysis/instrumentation , Dentin-Bonding Agents/chemistry , Dentin/pathology , Epoxy Resins/chemistry , Glass/chemistry , Incisor/pathology , Random Allocation , Resin Cements/chemistry , Root Canal Preparation/methods , Stress, Mechanical , Silanes/chemistry , Tooth Fractures/classification , Tooth Root/pathologyABSTRACT
OBJECTIVE: The aim of this study was to evaluate the fracture strength and failure mode of flared bovine roots restored with different intraradicular posts. MATERIAL AND METHODS: Fifty bovine incisors with similar dimensions were selected and their roots were flared until 1.0 mm of dentin wall remained. Next, the roots were allocated into five groups (n=10): GI- cast metal post-and-core; GII- fiber posts plus accessory fiber posts; GIII- direct anatomic post; GIV- indirect anatomic post and GV- control (specimens without intraradicular post). A polyether impression material was used to simulate the periodontal ligament. After periodontal ligament simulation, the specimens were subjected to a compressive load at a crosshead speed of 0.5 mm/min in a servo-hydraulic testing machine (MTS 810) applied at 135¨¬ to the long axis of the tooth until failure. The data (N) were subjected to ANOVA and Tukey's post-hoc test (¥á=0.05). RESULTS: GI and GIV presented higher fracture strength (p<0.05) than GII. GIII presented intermediate values without statistically significant differences (p>0.05) from GI, GII and GIV. Control specimens (GV) produced the lowest fracture strength mean values (p<0.05). Despite obtaining the highest mean value, GI presented 100 percent of unfavorable failures. GII presented 20 percent of unfavorable failures. GIII, GIV and GV presented only favorable failures. CONCLUSIONS: Although further in vitro and in vivo studies are necessary, the results of this study showed that the use of direct and indirect anatomic posts in flared roots could be an alternative to cast metal post-and-core.
Subject(s)
Animals , Cattle , Post and Core Technique/instrumentation , Tooth Fractures/physiopathology , Tooth Root/physiopathology , Cementation/methods , Chromium Alloys/chemistry , Composite Resins/chemistry , Dental Prosthesis Design , Dental Restoration Failure , Dental Materials/chemistry , Dental Stress Analysis/instrumentation , Dentin/pathology , Dentin/physiopathology , Glass/chemistry , Incisor/pathology , Incisor/physiopathology , Materials Testing , Models, Anatomic , Periodontal Ligament/physiopathology , Resin Cements/chemistry , Root Canal Filling Materials/chemistry , Root Canal Preparation/methods , Stress, Mechanical , Tooth Root/pathologyABSTRACT
Background: Post design and material has very important effects on dentinal stress distribution since the post placement can create stresses that lead to root fracture. Materials and Methods: In this study we use finite element analysis (FEA) to evaluate stress distribution on endodontically treated maxillary central incisors that have been restored with different prefabricated posts. Six models were generated from the image of anatomical plate: Four metallic posts (ParaPost XH, ParaPost XT, ParaPost XP, and Flexi-Flange) and one fiberglass post (ParaPost Fiber Lux). The sixth model was a control-a sound maxillary central incisor. We used CAD software and exported the models to ANSYS 9.0. All the materials and structures were considered elastic, isotropic, homogeneous, and linear except the fiberglass post which was considered orthotropic. The values for the mechanical properties were obtained by a review of the literature and the model was meshed with 8-node tetrahedral elements. A load of 2N was applied to the lingual surface at an angle of 135°. Results: The stress results were recorded by shear stress and von Mises criteria; it was observed that there was no difference for stress distribution among the titanium posts in the radicular portions and into posts. There was higher stress concentration on the coronary portion with the titanium posts than with the glass fiber post. It seems that the metallic posts' external configuration does not influence the stress distribution. Conclusion: Fiber posts show more homogeneous stress distribution than metallic posts. The post material seems to be more relevant for the stress distribution in endodontically treated teeth than the posts' external configuration.
Subject(s)
Aluminum Silicates/chemistry , Biomechanical Phenomena , Composite Resins/chemistry , Computer Simulation , Computer-Aided Design , Crowns , Dental Materials/chemistry , Dental Porcelain/chemistry , Dental Prosthesis Design , Dentin/physiopathology , Elasticity , Finite Element Analysis , Glass/chemistry , Humans , Incisor/physiopathology , Materials Testing , Maxilla/physiopathology , Models, Biological , Post and Core Technique/instrumentation , Potassium Compounds/chemistry , Software , Stress, Mechanical , Titanium/chemistry , Tooth Root/physiopathology , Tooth, Nonvital/physiopathologyABSTRACT
El poste debe emplearse solamente cuando no haya estructura dental remanente suficiente para darle retencion a la restauración, ya que el único propósito de restaurar una pieza con un poste es el de crear una subestructura en la que se pueda detener una restauración final. La idea de que un poste refuerza la estructura remanente de un órgano dentario debe desecharse, ya que en la mayoría de los casos, la colocación de un poste favorece la debilitación del órgano dentario. Es importante revisar los parámetros para la preparación y colocación de postes, para que tanto el tratamiento endodóntico como la restauración final sean exitosos
Subject(s)
Post and Core Technique/standards , Post and Core Technique/trends , Tooth, Nonvital , Root Canal Preparation/methods , Tooth Root/physiopathology , Post and Core Technique/classification , Post and Core Technique/instrumentation , Tooth, NonvitalABSTRACT
O presente trabalho tem como objetivo descrever a dinâmica de desenvolvimento da lesäo de cárie radicular, permitindo um melhor entendimento dos fatores etiológicos da doença. A partir desse conhecimento, o Cirurgiäo-Dentista estará melhor capacitado para diagnosticar näo só o risco como também o grau de atividade da cárie, possibilitando o estabelecimento de um adequado plano de tratamento centrado na promoçäo de saúde e consequentemente em um efetivo controle da doença
Subject(s)
Root Caries/diagnosis , Root Caries/etiology , Root Caries/physiopathology , Tooth Root/physiopathologyABSTRACT
Os pacientes desdentados totais, portadores ou näo de prótese total, säo, via de regra, considerados pelos profissionais como pacientes que já passaram por situaçöes diversas que os levaram a um estágio final, em que o único problema a ser solucionado é a confecçäo de uma prótese total. Säo muitos os trabalhos que contrariam essa idéia. Esses trabalhos provam a existência ou freqüência de raízes residuais, dentes inclusos, cistos etc., os quais obrigam o profissional a intervir em rebordos de maneira urgente devido à proporçäo de alteraçöes. Tais problemas poderiam ser evitados com a utilizaçäo de uma técnica radiográfica oclusal, antecedente ao tratamento protético (auxiliando no diagnóstico)
Subject(s)
Mouth, Edentulous/diagnosis , Mouth, Edentulous/rehabilitation , Denture, Complete/standards , Radiography, Dental , Diagnosis, Oral , Tooth Root/physiopathologyABSTRACT
O tratamento de dentes com rizogênese incompleta difere, sob vários aspectos, do tratamento endodôntico convencional. Buscando dados na literatura e também baseados na própria experiência clínica, os autores abordam a questäo e sugerem uma conduta para os casos em que a necrose pulpar for diagnosticada
Subject(s)
Dental Pulp Necrosis/diagnosis , Dental Pulp Necrosis/therapy , Tooth Root/abnormalities , Tooth Root/physiopathologyABSTRACT
A relaçäo polpa-periodonto, através dos túbulos dentinários, é somente considerada quando se admite a perda do cemento que recobre a raiz, devido à erosäo decorrente da doença periodontal ou da raspagem radicular. Estas vias permitem a comunicaçäo da doença periodontal para a polpa, e das doenças/necroses pulpares, para o periodonto. Os poucos trabalhos sobre a presença ou ausência da permeabilidade do cemento que recobre a raiz parecem ser conflitantes. Assim esta investigaçäo faz uma comparaçäo da permeabilidade do cemento e da dentina adjacente de dentes que apresentam doença periodontal e de dentes sadios. Foi usado como marcador o corante azul de metileno. Vinte e oito dentes doentes e dez dentes sadios tiveram as coroas, terços médios e apicais da raiz, impermeabilizados com éster de cianoacrilato de etila e foram submetidos ao corante em imersäo por 72 horas. Após esse tempo, os espécimes sofreram cortes transversais na regiäo cervical da raiz, e esses cortes foram observados em lupa estereoscópica com aumento de 4 vezes. Os resultados mostraram que tanto dentes sadios como os portadores de doença periodontal, permitiram a passagem do corante através do cemento e dentina, atigindo o canal radicular na maioria dos espécimes. Näo há diferenças estatísticas nos graus de permeabilidade entre raízes de dentes sadios e doentes
Subject(s)
Dental Pulp Cavity/anatomy & histology , Dental Pulp Cavity/physiology , Dental Pulp Cavity/physiopathology , Dentin Permeability , Periodontal Diseases/complications , Periodontal Diseases/diagnosis , Periodontal Diseases/physiopathology , In Vitro Techniques , Tooth Root/anatomy & histology , Tooth Root/physiology , Tooth Root/physiopathology , Dental ScalingABSTRACT
Para a presente pesquisa foram selecionadas 37 crianças, na faixa etária de 5 a 11 anos. Realizou-se exame radiográfico da regiäo de molares decíduos, com o objetivo de correlacionar radiograficamente a reabsorçäo radicular fisiológica de molares decíduos e o estágio de rizogênese dos sucessores permanentes. Pode-se concluir que existem uma correlaçäo direta entre reabsorçäo radicular dos dentes decíduos e rizogênese de seu sucessor permanente, em medidas quantitativas
Subject(s)
Humans , Child , Child, Preschool , Root Resorption/diagnosis , Tooth, Deciduous/physiopathology , Tooth Eruption , Tooth Root/physiopathologyABSTRACT
O objetivo do presente estudo foi avaliar a qualidade do selamento marginal apical promovido pelo uso de três técnicas de obturaçäo endodôntica (McSpadden original e modificada e condensaçäo lateral). Para tal utilizaram-se 30 incisivos centrais superiores humanos extraídos cujos canais radiculares foram preparados e obturados pelas referidas técnicas. Ao exame da infiltraçäo apical pelo azul de metileno, as técnicas de McSpadden modificada e a técnica da condensaçäo lateral exibiram valores estatisticamente menores que a técnica de McSpadden original