Efeito do desafio ácido nas propriedades superficiais das camadas externa e interna de dentes acrílicos reforçados / Effect of acid challenge on the surface properties of external and internal layers of cross-linked acrylic teeth

Introdução: Os dentes acrílicos artificiais devem apresentar característica de resistência aos ácidos, a fim de assegurar a manutenção de suas propriedades, ao longo de sua vida útil. Entretanto, não há estudos disponíveis na literatura pertinente sobre as propriedades superficiais de dureza e rugosidade das diferentes camadas de resina acrílica que compõem os dentes artificiais submetidos a ensaios de erosão simulada. Objetivo: Avaliar a dureza e rugosidade superficiais das camadas externa e interna de dentes artificiais acrílicos reforçados submetidos a desafio ácido. Metodologia: Molares (SR Postaris e Trilux) seccionados transversalmente foram avaliados inicialmente quanto à dureza Vickers e rugosidade. Esses ensaios foram repetidos após metade das amostras de cada tipo de dente (n=10) ser imersa em água destilada (controle) e outra metade em vinagre durante 15 min/dia por 28 dias. Os resultados foram analisados por ANOVA 2-critérios e teste de Tukey (α=0,05). Resultado: A dureza inicial da camada externa dos dois diferentes tipos de dente não sofreu alteração significativa pelo desafio ácido (p>0,05) e a imersão em vinagre não causou efeito deletério à dureza inicial da camada interna dos dois tipos de dentes avaliados (p>0,05). Após 28 dias, a rugosidade inicial de ambos os tipos de dentes estudados, para as duas camadas, não foi alterada com água ou vinagre (p>0,05). Conclusão: Os dentes acrílicos reforçados foram resistentes ao desafio ácido uma vez que suas camadas interna e externa não apresentaram alteração significativa de dureza e rugosidade superficiais.

Introduction: Artificial acrylic teeth must be resistant to acids for ensure the maintenance of their properties throughout their useful life. However, there are no studies available in the literature about the surface properties of hardness and roughness of the different layers of acrylic resin that make up the artificial teeth submitted to simulated erosion tests. Objective: To evaluate the surface hardness and roughness of external and internal layers of artificial cross-linked acrylic teeth submitted to acid challenge. Methodology: First molars (SR Postaris and Trilux) transversely sectioned had its Vickers hardness and roughness initially evaluated. These tests were repeated after half of the tooth samples (n=10) be immersed into distilled water (control) and half in vinegar during 15 min/day for 28 days. Data were analyzed using 2-way ANOVA and Tukey's test (α=0.05). Result: The initial external layers hardness of both was not significantly altered by acid challenge (p> 0.05) and the immersion in vinegar caused no deleterious effect on the initial internal layers hardness of the two tested teeth (p>0.05). After 28 days, the initial roughness of both teeth evaluated for the two layers was not affected by water or vinegar (p>0.05). Conclusion: The reinforced acrylic teeth were resistant to acid challenge since its internal and external layers showed no significant change in hardness and surface roughness.

Squamous cell carcinoma arising from inverted schneiderian papilloma: a case report with oral involvement.

Inverted Schneiderian papilloma is an uncommon benign tumor that presents tendency to recur and propensity to be associated with malignancy in approximately 10% of the cases. Some of these lesions are isolated in the maxillary sinus, and predominantly affect white males with mean age of 50 years. We report a case of squamous cell carcinoma arising from inverted Schneiderian papilloma in the maxillary sinus extending to the mouth. The patient was submitted to extraction of a maxillary molar tooth four months before the exacerbation of the symptoms of nasal airway obstruction and facial enlargement. Computed tomography scan revealed a sinonasal mass causing opacification of the right maxillary sinus with destruction of the lateral nasal wall and maxillary sinus floor. The patient was referred to an oncology center for treatment and died from tumor progression one year after the cancer was diagnosed. The intention of this report is to alert dentists to include the inverted Schneiderian papilloma, either associated with squamous cell carcinoma, or not, in the differential diagnosis of maxillary sinus tumors with aggressive behavior, which may extend to the oral cavity or involve roots of teeth.