RESUMO
This study compared the effects of various surface treatments and techniques on the marginal leakage of full-coverage crowns using a quasi-three-dimensional evaluation. Crowns were cast using a gold-silver-palladium alloy by means of the lost-wax technique. Twenty-eight recently extracted human molars were divided randomly into four groups according to surface treatment before crown cementation: (1) no pretreatment (negative control), (2) primer (positive control), (3) resin coating and primer, and (4) phosphoric acid, sodium hypochlorite, and primer. All specimens were cemented with composite cement. The lowest marginal leakage was observed in group 4. Variation in marginal leakage between specimens originating from the same tooth was observed.
Assuntos
Coroas , Colagem Dentária/métodos , Corrosão Dentária/métodos , Infiltração Dentária/prevenção & controle , Preparo Prostodôntico do Dente/métodos , Análise de Variância , Dentina , Adesivos Dentinários , Humanos , Dente Molar , Cimentos de Resina , Hipoclorito de Sódio , Estatísticas não Paramétricas , Propriedades de SuperfícieRESUMO
Plasma and halogen lamp units were used to photo-cure a composite resin for porcelain bonding. Mean shear bond strengths to dentin after light curing through porcelain of 1 and 2 mm thickness ranged from 20 to 27 MPa before and after thermocycling, indicating no significant effects due to porcelain thickness, curing method, or thermocycling, except for plasma curing for 3 s through porcelain of 2 mm thickness that overcame thermocycling. The mean bond strength in this group was significantly lower than both that before thermocycling and that of the porcelain of 1 mm thickness. Knoop hardness values for plasma curing for 3 s through porcelain of 2 mm thickness were significantly lower than the others. These results suggest that plasma light for 3 s is not sufficient to cure composite resin cement through porcelain of 2 mm thickness.
