Avaliação do efeito de diferentes materiais de preenchimento associados a pinos intra-radiculares na resistencia a fratura de raizes debilitadas

Orientadores: Luis Alexandre Maffei Sartini Paulillo, Luiz Andre Freire PimentaTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de PiracicabaResumo: A preservação e a restauração de dentes severamente debilitados sem suporte dentinário no terço cervical do canal radicular é um procedimento difícil. A reconstrução dessas rafzes possibilitaria tratamentos mais conservadores. Por isso, o objetivo deste trabalho foi avaliar a resistência à fratura de rafzes hfgidas e debilitadas reconstrufdas internamente com diferentes materiais de preenchimento atuando como IIdentina artificial" associados a pino intra-radicular. Foram selecionadas 75 rafzes de incisivos inferiores bovinos com volumes semelhantes. Dessas, sessenta foram desgastadas internamente até apresentarem dimensões padronizadas, simulando enfraquecimento. As rafzes debilitadas foram preenchidas com diferentes adesivos dentinários e materiais restauradores, sendo que em trinta delas os pinos pré-fabricados eram posicionados junto com o material de preenchimento. As demais rafzes debilitadas reconstrufdas e as hfgidas' foram preparadas para receber os pinos intra-radiculares, posteriormente fixados com o agente cimentante resinoso. Foram obtidos, assim, cinco grupos experimentais: GRUPO 1 - raiz hfgida com pino pré-fabricado fixado com agente cimentante resinoso; GRUPO 2 - raiz debilitada preenchida com agente cimentante resinoso associado ao pino pré-fabricado; GRUPO 3 - raiz debilitada preenchida com cimento de ionômero de vidro modificado por resina associado ao pino pré-fabricado; GRUPO 4 - raiz debilitada preenchida com resina composta mod,ificada por poliácido e com posterior fixação do pino pré-fabricado com agente cimentante resinoso e GRUPO 5 - raiz debilitada preenchida com resina composta e com posterior fixação do pino pré-fabricado com agente cimentante resinoso. Os corpos-de-prova foram submetidos ao teste de resistência à fratura com aplicação de carregamento tangencial de compressão em um ângulo de 1350 em relação ao longo eixo da raiz, a uma velocidade de 0,5mm/min. Os resultados mostraram diferenças estatisticamente significantes em relação à condição da raiz, sendo as hfgidas mais resistentes à fratura que as debilitadas. Avaliando o material de preenchimento, as rafzes restauradas com o agente cimentante ALL BOND C&B apresentaram os menores valores de resistência à fratura, mostrando diferença estatisticamente significante apenas quando comparado ao VITREMER. Já os materiais VITREMER, DYRACT AP e Z100 exibiram o mesmo comportamento, não havendo, entre eles, diferenças estatisticamente significantesAbstract: The preservation and the restoration of severely weakened teeth, without dentinal support in the cervical zone of the radicular canal is a difficult procedure. The reconstruction of these roots would make possible more conservative treatments. That is why, the purpose of this study was to evaluate the resistance to fracture of whole and weakened root internally reconstructed with different filling materiais acting as an "artificial dentin" associated to the prefabricated post into the root canal. Seventy-five roots were selected of bovine mandibular incisors with similar bulks. From those, sixty roots were internally wore until presente standardized dimensions, simulating weakened roots. Those roots were filled with different dentinal adhesives and restorative materiais, being thirty of them with the prefabricated posts placed with the filling material. The other weakened filled roots and the whole roots were prepared to receive the intraradicular posts, subsequently fixed with resin cement agent. Thus, were obtained five experimental groups: GROUP 1 - whole root with prefabricated post fixed with resin cement agent; GROUP 2 - weakened root filled with resin cement agent; GROUP 3 - vyeakened root filled with resin-modified glass ionomer associated to the prefabricated post; GROUP 4 - weakened root filled with resin modified by polyacid and with posterior fixing of the prefabricateá post with resin cement agent and GROUP 5 - weakened root filled with composite resin and with posterior fixing of the prefabricated post with resin cement agent. The specimens were submitted to resistance test to fracture with compressive load in an angle of 135 degrees in relation to the long axis of the root, in a speed of 0,5 mm/min. The results showed statiscally significant differences in relation to the condition of the root, being the whole roots more resistants to fracture than the weakened roots. Evaluating the filling material, roots restorated with the resin cement agent ALL BONO C&B presented the least values of resistance to fracture, showing statiscally significant difference only when compared with the VITREMER. The materiais VITREMER, OYRACT AP and Z100 had the same behaviour, do not existing statiscally significant differer:tces among themDoutoradoDentísticaDoutor em Clínica Odontológic

Resistencia a fratura de raizes debilitadas reconstruidas morfologicamente com sistema adesivo associado a pinos intra-radiculares

Orientadores: Luis Roberto Marcondes Martins, Luis Alexandre Maffei Sartini PaulilloDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de PiracicabaResumo: A restauração de dentes tratados endodonticamente através da colocação de núcleos metálicos fundidos ou pinos pré-fabricados é dificultada quando há grande perda de estrutura dentinária. Dessa maneira, o objetivo deste trabalho foi avaliar a resistência à fratura de raízes debilitadas através da utilização de um sistema adesivo atuando como "dentina artificial" associado aos pinos intra-radiculares nas reconstruções morfológicas. As raízes de 76 dentes unirradiculares, entre incisivos centrais superiores e caninos superiores, foram separadas das coroas e divididas de acordo com seus volumes. Metade dessas raízes foram desgastadas internamente até apresentarem dimensões padronizadas, simulando enfraquecimento. Tais raízes foram preenchidas com sistema adesivo/compósito. Trinta e oito raízes, entre debilitadas e hígidas, foram preparadas para receberem núcleos metálicos fundidos e, as demais, para receberem pinos pré-fabricados, ambos cimentados com cimento de fosfato de zinco. Os corpos de prova foram submetidos ao teste de resistência à fratura em Máquina de Ensaio Universal com aplicação da carga compressiva em um ângulo de 1350 em relação ao longo eixo da raiz, a uma velocidade de 0,5 mm/min. Os resultados mostrar~m diferenças estatisticamente significantes dos fatores experimentais Volume da Raiz, sendo as raízes grandes as que apresentaram maior resistência à fratura; COhdiçlfo da Raiz, onde as raízes hígidas foram mais resistentes e Tipo de Pino Intraradicular, sendo que as raízes com pinos pré-fabricados cimentados apresentaram maior resistência à fratura. Também houve efeito significante da interação Volume da Raiz x Condição da Raiz, onde as raízes grandes e hígidas foram mais resistentes que as demais e da interação Condição da Raiz x Tipo de Pino Intra-radicular, sendo as raízes hígidas com pinos pré-fabricados as mais resistentes. Sob as condições estudadas, raízes grandes, hígidas e com pinos pré-fabricados cimentados apresentaram melhores resultados de resistência à fraturaAbstract: The restoration of endodontically treated teeth through the placement of cast posts and prefabricated posts is hindered when there is great loss of dentinal structure. In that way, the purpose of this in vitro study was to evaluate the resistance to fracture of weakened roots through the use of one adhesive system acting as an "artificial dentin" associated to the posts into the root canal in the morphologic reconstructions. The roots of 76 single-rooted maxillary teeth, between central incisors and canines, they were separeted from the crowns and divided in agreement with their bulks. Half of these roots were internally wore until to presente standardized dimensions, simulating weakened roots. Such roots were filled with adhesive system and composite. Thirty-eight roots, between weakened and health, were prepared to receive casts and, the others, to receive prefabricated posts, both fixed with zinc phosphate cement. The specimens were submitted to resistance test to fracture in an Universal Testing Machine with compressive load in an angle of 135 degrees in relation to the long axis of the root, in a speed of 0,5 mm/min. The results show statistically significant differences between the tested factors Root's bulk, being the big roots the most resistant to fracture; Root's conditio,!, where the health roots were more resistants and Kind of post into the root canal, being the roots with cemented prefabricated posts the ones that presented larger resistance to fracture. There is also significant effect of the interaction Root's bulk * Root's condition, where the big and health roots were more resistants than the others and of the interaction Root's condition * Kind of post into the root canal, being the health roots with prefabricated posts the most resistants. Under the studied conditions, bigand health roots with cemented prefabricated posts presented the best results of resistance to fractureMestradoDentísticaMestre em Clínica Odontológic

Statistical results on restorative dentistry experiments: effect of the interaction between main variables

Statistical analysis interpretation is a critical field in scientifc research. When there is more than one main variable being studied in a research, the effect of the interaction between those variables is fundamental on experiments discussion. However, some doubts can occur when the p-value of the interaction is greater than the signifcance level. OBJECTIVE: To determine the most adequate interpretation for factorial experiments with p-values of the interaction nearly higher than the signifcance level. MATERIALS AND METHODS: The p-values of the interactions found in two restorative dentistry experiments (0.053 and 0.068) were interpreted in two distinct ways: considering the interaction as not signifcant and as signifcant. RESULTS: Different findings were observed between the two analyses, and studies results became more coherent when the signifcant interaction was used. CONCLUSION: The p-value of the interaction between main variables must be analyzed with caution because it can change the outcomes of research studies. Researchers are strongly advised to interpret carefully the results of their statistical analysis in order to discuss the findings of their experiments properly

Occlusal Interferences: How Can This Concept Influence The Clinical Practice?

This brief review discusses the role of occlusal interferences on the development and progression of temporomandibular dysfunction (TMD) and postural disorders. The eligible literature is described and critically presented to demonstrate that occlusal interferences are an important factor in the risk of TMD. Several studies have demonstrated through their findings that the use of occlusal adjustments, whether or not associated with restorative procedures, might avoid the development of articular problems in vulnerable patients. The occlusal interferences caused by restorative procedures or orthodontic treatment can cause TMDs in susceptible patients, and occlusal adjustments can be an alternative in the treatment of these TMDs.4487-9

Dentin Bonding On Different Walls Of A Class Ii Preparation.

To evaluate the bond strength on different cavity walls of Class II preparations. Different bonding systems and the effect of thermomechanical cycling were investigated. Human third molars received MOD preparations with dentin margins. Teeth were randomly assigned to 18 groups (n=5) according to the combination of cavity wall (axial, occlusal, and gingival), bonding system (Single Bond Plus, Clearfil SE Bond, and Adper Prompt) and the occurrence of thermomechanical cycling. Restorations were concluded with Filtek Z250 composite. Specimens were sectioned according to the respective cavity wall (4 slabs/restoration), and the adhesive interface was trimmed to an hourglass shape (1 mm2). Slabs were tested under tension, and failure mode was observed. Bond strength data were analyzed with three-way ANOVA/Tukey's test. Single Bond Plus and Clearfil SE Bond performed similarly under most experimental conditions. Single Bond Plus presented similar bond strength on the three cavity walls, regardless of the aging condition. Clearfil SE Bond exhibited significant differences among cavity walls: the occlusal wall showed higher means in both aging conditions. Non-aged gingival walls and aged axial and gingival walls yielded lower means. Non-aged Adper Prompt produced similar bond strengths on the three cavity walls. After thermomechanical cycling, the gingival wall showed lower means. The effect of cavity walls was dependent on the bonding system and thermomechanical cycling. Adper Prompt demonstrated bond strengths lower than Single Bond Plus or Clearfil SE Bond under most experimental conditions.1017-2

Visual evaluation of in vitro cariostatic effect of restorative materials associated with dentifrices

This study evaluated in vitro the cariostatic effect of 6 restorative materials with and without fluoride release (Fuji II LC, F-2000, Degufil Mineral, Sure Fil and Z-250) associated with a fluoridated and a non-fluoridated dentifrice (Sensodyne Original Formula and Sensodyne Sodium Bicarbonate), on human enamel. Class V-like cavities were prepared on 240 enamel slabs, assigned to 12 groups (6 materials and 2 dentifrices). After cavity restoration, the slabs were submitted to a thermocycling regimen of 1000 thermal cycles and demineralization/remineralization cycles. During pH cycles, slurries of fluoridated and non-fluoridated dentifrices were applied for 5 min. Formation of artificial caries-like lesions was scored independently and blindly by 5 calibrated examiners according to an ordinal scale ranked 0 to 3 by visual examination. The results were analyzed statistically by the Kruskal-Wallis test and pair-wise comparisons (alpha=0.05). There were no significant differences (p>0.05) among the restorative materials associated with the fluoridated dentifrice. When used in association with the non-fluoridated dentifrice, Ketac-Fil showed the highest cariostatic effect followed by Fuji II LC and the other materials. Ketac-Fil was the only material that did not differ statistically when combined with either the fluoridated or the non-fluoridated dentifrice. In conclusion, under the tested experimental conditions, the association of restorative materials and fluoridated dentifrice yielded higher cariostatic effect, except for the conventional glass ionomer cement, whose cariostatic effect was not influenced by the type of dentifrice.O objetivo deste trabalho foi avaliar, in vitro, o efeito cariostático de 6 materiais restauradores contendo ou não flúor (Fuji II LC, F-2000, Degufil Mineral, Sure Fil and Z-250) associados à aplicação de dentifrícios (fluoretado e não-fluoretado; Sensodyne Fórmula Original and Sensodyne Sodium Bicarbonate) em esmalte dental humano. Cavidades classe V foram preparadas no esmalte de 240 fragmentos dentais, aleatoriamente divididos em 12 grupos (6 materiais e 2 dentifrícios). Após serem restauradas as cavidades, os fragmentos foram submetidos a ciclos térmicos e de desmineralização e remineralização, simulando um alto desafio cariogênico. Sobre os fragmentos restaurados, ainda, foram aplicados dentifrícios contendo ou não flúor, 5 min por dia. As diferenças no desenvolvimento de lesões experimentais de cárie adjacente às restaurações foram avaliadas por 5 examinadores calibrados, através de inspeção visual, atribuindo-se escores de 0 a 3. Os resultados foram avaliados pelo teste de Kruskal-Wallis seguido pelo teste de comparações múltiplas (alfa=0,05). Quando associados ao dentifrício fluoretado, os materiais restauradores não diferiram entre si em relação ao potencial cariostático (p>0,05). Quando os materiais foram utilizados em associação com o dentifrício não-fluoretado o Ketac-Fil apresentou o maior potencial cariostático, seguido pelo Fuji II LC e pelos demais materiais. O Ketac-Fil foi o único material que não diferiu significativamente quando associado com o dentifrício com ou sem flúor. Sob as condições experimentais do estudo, a associação dos materiais restauradores ao dentifrício fluoretado resultou em uma maior ação cariostática, exceto para o cimento de ionômero de vidro convencional, que não diferiu com a aplicação dos dentifrícios.112118Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Impact of light-curing time and aging on dentin bond strength of methacrylate- and silorane-based restorative systems

AIM: To evaluate the impact of different light-curing times on dentin microtensile bond strength of two restorative systems after 24 h and 6 months of water storage. METHODS: Standardized Class II preparations were performed in 56 freshly-extracted human molars (n = 7), restored with methacrylate- or silorane-based restorative systems, and light-cured using a light-emitting diode at 1390 mW/cm2 by the recommended manufacturers' time or double this time. After storage for 24 h at 37 oC, the teeth were sectioned to yield a series of 0.8-mm thick slices. Each slab was trimmed into an hourglass shape of approximately 0.64 mm2 area at the gingival dentin-resin interface. Specimens were tested using universal testing machine at crosshead speed of 0.5 mm/min until failure, after 24 h and 6 months of storage. Data were statistically analyzed by three-way ANOVA and Tukey's test (α = 0.05). RESULTS: The highest bond strength values were recorded for the groups restored with methacrylate system (p0.05). CONCLUSIONS: Bond strength was influenced by the material and light-curing time, but the 6-month storage did not affect the bond strength of restorations133213218FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP2010/05666-9; 2010/15076-