RESUMO
The effects of sandblasting media and steam cleaning treatment after sandblast were examined on tensile bond strength of porcelain to titanium. The use of the commercially available silica-coated alumina particles for sandblast was significantly effective for increasing bond strength than the conventional alumina. It might be due to the increased surface roughness and existence of remaining silica on titanium surface. Additional application of the steam cleaning on titanium surface after sandblasting could make the surface configuration clear in SEM by removing some sandblasted particles loosely embedded in titanium as well as the debris and oily contaminants. The resultant bond strength was significantly improved to reach almost the maximum strength of this porcelain-titanium system regardless of the kind of sandblasting media used, which was confirmed by the observation of the failure mode showing that most of the fracture surface was occupied by cohesive failure in porcelain.
Assuntos
Colagem Dentária , Corrosão Dentária/métodos , Materiais Dentários/química , Porcelana Dentária/química , Vapor , Titânio/química , Óxido de Alumínio/química , Cimentos Dentários/química , Polimento Dentário , Análise do Estresse Dentário , Microanálise por Sonda Eletrônica , Humanos , Teste de Materiais , Microscopia Eletrônica de Varredura , Pressão , Dióxido de Silício/química , Estresse Mecânico , Propriedades de Superfície , Resistência à Tração , Fatores de TempoRESUMO
Childhood systemic diseases are commonly treated with steroids. Consequently, steroid-induced osteoporosis is often observed as a side effect of steroid therapy. However, osteoporosis of tibia resulting from steroid therapy has not been reported yet. Herein we constructed a steroid-induced osteoporosis in tibia of the growing phase rats to examine internal structural changes of the bone and tried to find out the effect of bisphosphonates as a new and early treatment method. Biomechanical analysis was performed using two-dimensional microdensitometry and three-dimensional pQCT method. In addition, the following evaluations were carried out: noninvasive bone strength measurements in steroid-induced osteoporotic rat tibiae; comparing the effectiveness of single high-calcium diet versus combined treatment of high calcium and bisphosphonate for osteoporosis; and quantitative measurement of four elements (Ca, P, Mg, Zn) in bone matrix. Our data suggested that a combined treatment of high calcium and bisphosphonate was an effective new method to improve and treat steroid-induced osteoporosis in childhood.
Assuntos
Conservadores da Densidade Óssea/uso terapêutico , Desenvolvimento Ósseo/efeitos dos fármacos , Cálcio da Dieta/uso terapêutico , Ácido Etidrônico/uso terapêutico , Osteoporose/induzido quimicamente , Prednisona/análogos & derivados , Tíbia/efeitos dos fármacos , Absorciometria de Fóton , Animais , Fenômenos Biomecânicos , Densidade Óssea/efeitos dos fármacos , Matriz Óssea/química , Cálcio/análise , Modelos Animais de Doenças , Imageamento Tridimensional , Magnésio/análise , Masculino , Osteoporose/tratamento farmacológico , Periósteo/efeitos dos fármacos , Periósteo/patologia , Fósforo/análise , Prednisona/efeitos adversos , Distribuição Aleatória , Ratos , Ratos Wistar , Estresse Mecânico , Tíbia/crescimento & desenvolvimento , Tíbia/patologia , Tomografia Computadorizada por Raios X , Zinco/análiseRESUMO
A densely sintered high-purity alumina has been successfully utilized as a coping for all-ceramic crown. In order to apply the alumina coping to the porcelain laminate veneer restoration for the discolored teeth, the present study evaluated its masking ability when it was thinner than the proposed thickness for the crown. Colorimetric examination was performed on white and black backgrounds for the 0.7 mm thick porcelain laminate veneer with 0.40 or 0.25 mm thick alumina coping and 0.7 mm thick porcelain without coping. With the presence of the coping, the porcelain appeared significantly lighter. Judging from the calculated color differences delta E and the literature, it was suggested that the masking ability of the alumina coping would be sufficient with a 0.25 mm thickness for the porcelain laminate veneer for heavily discolored teeth.