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Desgaste dentário em esmalte e cerâmica de dissilicato de lítio : estudo in vitro
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Objetivo: Avaliar a progressão do desgaste do esmalte quando em oclusão com uma cerâmica de dissilicato de lítio, in vitro, em meio neutro.
Materiais e Métodos: Terceiros molares, hígidos e desinfetados, foram seccionados para aquisição de amostras de esmalte planas (E) (n=12). Dois blocos de IPS e.max® CAD HT A3,5 foram fresados e tratados termicamente, obtendo amostras de cerâmica (C) (n=12). As amostras C foram colocadas como corpo (superior), e as amostras E foram colocadas como contra-corpo (inferior) no Chewing Simulator; submersas em saliva artificial e submetidas ao protocolo de atrição, constituído por 3 ciclos de desgaste t24, t48 ou t96. Com recurso ao scanner CEREC Primescan® e S600 Zirkonzahn®, efetuou-se um scan inicial, antes do primeiro ciclo de atrição de forma a obter uma referência para posterior análise do volume de amostra perdido (%vol rel). Os scans foram repetidos no final de cada ciclo. Os valores de %vol rel foram analisados estatisticamente.
Resultados: De modo geral, ocorreu uma redução do volume das amostras ao longo do tempo, sendo estatisticamente significativo (p<0,001) para todos os grupos quando analisados com o teste ANOVA with repeated measures. Pontualmente, ocorreram reduções que não foram estatisticamente significativas para os grupos: ZZ-E-DL entre t24 e t48 (p=0,105) e Pr-E-DL entre t24 e t48 (p=0,057). O teste mostrou ainda que não se verificaram diferenças entre os grupos ao longo do tempo decorrido (p=0,953). Não se verificaram diferenças estatisticamente significativas entre os valores de desgaste sofridos pelos diferentes grupos, quando comparados em cada um dos pontos de análise t24, t48 ou t96.
Conclusão: Considerando os resultados obtidos neste estudo in vitro, é possível afirmar que o desgaste dentário do esmalte e da cerâmica dissilicato lítio é igual; e que o Cerec Primescan® bem como o S600 Zirkonzahn® permitem medir o desgaste dentário ao longo do tempo.
Objective: To evaluate the progression of enamel wear when in occlusion with a lithium disilicate ceramic, in vitro, in a neutral environment. Materials and Methods: Healthy and disinfected third molars were sectioned to acquire flat enamel samples (E) (n=12). Two IPS e.max® CAD HT A3.5 blocks were milled and heat-treated to obtain ceramic samples (C) (n=12). The C samples were placed as the body (top), and the E samples were placed as the counter-body (bottom) in the Chewing Simulator; submerged in artificial saliva and subjected to the attrition protocol, consisting of 3 wear cycles t24, t48 or t96. Using the CEREC Primescan® and S600 Zirkonzahn® scanners, an initial scan was carried out before the first attrition cycle in order to obtain a reference for later analysis of the volume loss (%vol rel). The scans were repeated at the end of each cycle. The %vol rel values were analysed statistically. Results: In general, there was a reduction in volume over time, which was statistically significant (p<0.001) for all groups when analysed with the ANOVA with repeated measures test. There were occasional reductions that were not statistically significant for the groups: ZZ-E-DL between t24 and t48 (p=0.105) and Pr-E-DL between t24 and t48 (p=0.057). The test also showed that there were no differences between the groups over time (p=0.953). There were no statistically significant differences between the wear values suffered by the different groups when compared at each of the analysis points t24, t48 or t96. Conclusion: Considering the results obtained in this in vitro study, it is possible to state that tooth wear on enamel and lithium disilicate ceramic is the same; and that Cerec Primescan® and S600 Zirkonzahn® allow tooth wear to be measured over time.
Objective: To evaluate the progression of enamel wear when in occlusion with a lithium disilicate ceramic, in vitro, in a neutral environment. Materials and Methods: Healthy and disinfected third molars were sectioned to acquire flat enamel samples (E) (n=12). Two IPS e.max® CAD HT A3.5 blocks were milled and heat-treated to obtain ceramic samples (C) (n=12). The C samples were placed as the body (top), and the E samples were placed as the counter-body (bottom) in the Chewing Simulator; submerged in artificial saliva and subjected to the attrition protocol, consisting of 3 wear cycles t24, t48 or t96. Using the CEREC Primescan® and S600 Zirkonzahn® scanners, an initial scan was carried out before the first attrition cycle in order to obtain a reference for later analysis of the volume loss (%vol rel). The scans were repeated at the end of each cycle. The %vol rel values were analysed statistically. Results: In general, there was a reduction in volume over time, which was statistically significant (p<0.001) for all groups when analysed with the ANOVA with repeated measures test. There were occasional reductions that were not statistically significant for the groups: ZZ-E-DL between t24 and t48 (p=0.105) and Pr-E-DL between t24 and t48 (p=0.057). The test also showed that there were no differences between the groups over time (p=0.953). There were no statistically significant differences between the wear values suffered by the different groups when compared at each of the analysis points t24, t48 or t96. Conclusion: Considering the results obtained in this in vitro study, it is possible to state that tooth wear on enamel and lithium disilicate ceramic is the same; and that Cerec Primescan® and S600 Zirkonzahn® allow tooth wear to be measured over time.
Descrição
Dissertação para obtenção do grau de Mestre no Instituto Universitário Egas Moniz
Palavras-chave
Atrição Chewing simulator Desgaste dentário Dissilicato lítio