Desenvolvimento e validação de um novo protocolo para ciclagem térmica de materiais dentários

• Ano de defesa: 2014
• Autor(a) principal: Marinho, Caroline Cotes [UNESP]
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Estadual Paulista (Unesp)
• Palavras-chave em Português: Cerâmicas odontológicas; Materiais dentários; Resistência à tração; Dental ceramics
• Link de acesso: http://hdl.handle.net/11449/127561; http://www.athena.biblioteca.unesp.br/exlibris/bd/cathedra/31-08-2015/000843412.pdf

This study aimed to evaluate the thermal variation that occurs in the oral environment; predicted the number of thermal cycles and temperature variation which occurs during certain time periods and compared the results of the bond strength of ceramic and luting agent after different aging protocols. For this purpose, six volunteers used a removable device with wireless thermal sensor and they were monitored for three days, to develop a new thermal cycling protocol. After this step, 40 feldspathic ceramic blocks were cemented together with a resin luting agent (N = 20), divided into five groups (n = 4) and cut into slices. Aging of the slices were: C, immediate test (without aging); A, storage in water for 30 days; E, thermal cycling experimental protocol developed in this study; CIB, storage of the slices in mouth for 30 days; and ISO, thermal cycling protocol established by ISO 11405 (2003). The slices were cut into sticks for microtensile test. The failure analysis were performed in a stereomicroscope. Maximum temperature observed was 47.59 ̊C, the lowest temperature was 13.11 ̊C. The average daily temperature is between 34 ̊C and 36 ̊C. The average temperature change per day was 5.3 times, with an average duration of 183 s. A, CIB, and E groups showed strength values statistically lower than C group (p-value = 0.0002), and they were similar among them. The ISO group was similar to the groups C and IB. The failure type most commonly found for all groups was mixed mode. It concluded that occurs daily 6 temperature variations, with duration of 180 seconds. The ISO thermocycling protocol did not reduce the bond strength. The experimental cycling used in E, 180 thermal cycles with a temperature range of 50 ̊C and 10 ̊C for 180 seconds each and 36 ̊C intermediate baths was able to accelerate the degradation process of bond between ceramic and cement that occurred during storage in water for 30 days