title: [Effect of techniques of composite resin insertion and polymerization on microleakage and microhardness].
abstract: The aim of this study was to evaluate the influence of techniques of composite resin polymerization and insertion on microleakage and microhardness. One hundred and eighty class II cavities were prepared in bovine teeth and assigned to six groups: G1 - bulk filling + conventional polymerization; G2 - bucco-lingual increments + conventional polymerization; G3 - bulk filling + soft-start polymerization; G4 - bucco-lingual increments + soft-start polymerization; G5 - bulk filling + progressive polymerization; G6 - bucco-lingual increments + progressive polymerization. All cavities were restored with the Z100/Single Bond system (3M). After thermocycling, the samples were immersed in 2% methylene blue dye solution for 4 hours. Half of the samples were embedded in polystyrene resin, and Knoop microhardness was measured. The Kruskal-Wallis test did not reveal statistical differences (p > 0.05) between the polymerization and insertion techniques as to microleakage. Regarding microhardness, the two-way ANOVA and the Tukey test did not reveal statistical differences between the restorative techniques (p > 0.05), but progressive polymerization (G5 and G6) was associated with smaller Knoop microhardness values (p < 0.05): G = 144.11; G2 = 143.89; G3 = 141.14; G4 = 142.79; G5 = 132.15; G6 = 131.67. It was concluded that the evaluated polymerization and insertion techniques did not affect marginal microleakage, but a decrease in microhardness occurred when progressive polymerization was carried out.
authors.affiliation: Area de Dentística, Departamento de Odontologia Restauradora, Faculdade de Odontologia de Piracicaba, Universidade Estadual de Campinas, Brasil.
authors.forename: Cristiane Mariote
authors.initials: CM
authors.lastname: Amaral
authors.forename: Ana Karina Barbieri Bedran de
authors.initials: AK
authors.lastname: Castro
authors.forename: Luiz André Freire
authors.initials: LA
authors.lastname: Pimenta
authors.forename: Glaucia Maria Boni
authors.initials: GM
authors.lastname: Ambrosano
mesh_terms: D000180:Acrylic Resins; D000818:Animals; D002417:Cattle; D003188:Composite Resins; D003731:Dental Caries / Q000628:therapy*; D003763:Dental Leakage; D003793:Dental Restoration, Permanent; D006245:Hardness Tests; D011108:Polymers; D011140:Polyurethanes
chemical_list: D000180:Acrylic Resins; C029012:Composite Dental Resin; D003188:Composite Resins; D011108:Polymers; D011140:Polyurethanes