title: Effect of the curing method and composite volume on marginal and internal adaptation of composite restoratives.
abstract: The aim of the present study was to evaluate the influence of curing methods and composite volumes on the marginal and internal adaptation of composite restoratives. Two cavities with different volumes (Lower volume: 12.6 mm(3); Higher volume: 24.5 mm(3)) were prepared on the buccal surface of 60 bovine teeth and restored using Filtek Z250 in bulk filling. For each cavity, specimens were randomly assigned into three groups according to the curing method (n=10): 1) continuous light (CL: 27 seconds at 600 mW/cm(2)); 2) soft-start (SS: 10 seconds at 150 mW/cm(2)+24 seconds at 600 mW/cm(2)); and 3) pulse delay (PD: five seconds at 150 mW/cm(2)+three minutes with no light+25 seconds at 600 mW/cm(2)). The radiant exposure for all groups was 16 J/cm(2). Marginal adaptation was measured with the dye staining gap procedure, using Caries Detector. Outer margins were stained for five seconds and the gap percentage was determined using digital images on a computer measurement program (Image Tool). Then, specimens were sectioned in slices and stained for five seconds, and the internal gaps were measured using the same method. Data were submitted to two-way analysis of variance and Tukey test (p<0.05). Composite volume had a significant influence on superficial and internal gap formation, depending on the curing method. For CL groups, restorations with higher volume showed higher marginal gap incidence than did the lower volume restorations. Additionally, the effect of the curing method depended on the volume. Regarding marginal adaptation, SS resulted in a significant reduction of gap formation, when compared to CL, for higher volume restorations. For lower volume restorations, there was no difference among the curing methods. For internal adaptation, the modulated curing methods SS and PD promoted a significant reduction of gap formation, when compared to CL, only for the lower volume restoration. Therefore, in similar conditions of the cavity configuration, the higher the volume of composite, the greater the gap formation. In addition, modulated curing methods (SS and PD) can improve the interfacial quality of composite restorations through the reduction of internal gaps in lower volume composite restoratives.
authors.affiliation: Department of Restorative Dentistry, Piracicaba Dental School, University of Campinas-UNICAMP, Piracicaba–SP, Brazil.
authors.forename: Eduardo José
authors.initials: EJ
authors.lastname: Souza-Junior
authors.forename: Marcos Ribeiro
authors.initials: MR
authors.lastname: de Souza-Régis
authors.forename: Roberta Caroline Bruschi
authors.initials: RC
authors.lastname: Alonso
authors.forename: Anderson Pinheiro
authors.initials: AP
authors.lastname: de Freitas
authors.forename: Mario Alexandre Coelho
authors.initials: MA
authors.lastname: Sinhoreti
authors.forename: Leonardo Gonçalves
authors.initials: LG
authors.lastname: Cunha
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods; D000818:Animals; D017554:Carbon Compounds, Inorganic / Q000737:chemistry; D002417:Cattle; D003188:Composite Resins / Q000737:chemistry*; D055117:Curing Lights, Dental; D003737:Dental Cavity Preparation / Q000145:classification; D003738:Dental Cements / Q000737:chemistry; D003763:Dental Leakage / Q000145:classification; D018772:Dental Marginal Adaptation; D003764:Dental Materials / Q000737:chemistry*; D003775:Dental Polishing / Q000379:methods; D003793:Dental Restoration, Permanent / Q000145:classification; D018130:Diamond / Q000737:chemistry; D005456:Fluorescent Dyes; D007091:Image Processing, Computer-Assisted; D055115:Light-Curing of Dental Adhesives / Q000379:methods; D011829:Radiation Dosage; D011897:Random Allocation; D012235:Rhodamines; D017655:Silicon Compounds / Q000737:chemistry; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: C554641:Adper single bond 2; D017554:Carbon Compounds, Inorganic; D003188:Composite Resins; D003738:Dental Cements; D003764:Dental Materials; C444701:Filtek Z250; D005456:Fluorescent Dyes; D012235:Rhodamines; D017655:Silicon Compounds; D014867:Water; C022027:lissamine rhodamine B; D018130:Diamond; C022088:silicon carbide