title: Marginal integrity of restorations produced with a model composite based on polyhedral oligomeric silsesquioxane (POSS).
abstract: Marginal integrity is one of the most crucial aspects involved in the clinical longevity of resin composite restorations.
  
  
  OBJECTIVE
  To analyze the marginal integrity of restorations produced with a model composite based on polyhedral oligomeric silsesquioxane (POSS).
  
  
  METHODS
  A base composite (B) was produced with an organic matrix with UDMA/TEGDMA and 70 wt.% of barium borosilicate glass particles. To produce the model composite, 25 wt.% of UDMA were replaced by POSS (P25). The composites P90 and TPH3 (TP3) were used as positive and negative controls, respectively. Marginal integrity (%MI) was analyzed in bonded class I cavities. The volumetric polymerization shrinkage (%VS) and the polymerization shrinkage stress (Pss - MPa) were also evaluated.
  
  
  RESULTS
  The values for %MI were as follows: P90 (100%) = TP3 (98.3%) = B (96.9%) > P25 (93.2%), (p<0.05). The %VS ranged from 1.4% (P90) to 4.9% (P25), while Pss ranged from 2.3 MPa (P90) to 3.9 MPa (B). For both properties, the composite P25 presented the worst results (4.9% and 3.6 MPa). Linear regression analysis showed a strong positive correlation between %VS and Pss (r=0.97), whereas the correlation between Pss and %MI was found to be moderate (r=0.76).
  
  
  CONCLUSIONS
  The addition of 25 wt.% of POSS in methacrylate organic matrix did not improve the marginal integrity of class I restorations. Filtek P90 showed lower polymerization shrinkage and shrinkage stress when compared to the experimental and commercial methacrylate composite.
authors.affiliation: Laboratório Analítico de Biomateriais Restauradores, Faculdade de Odontologia, Universidade Federal Fluminense, Niterói, RJ, Brazil.
authors.forename: Luciano Ribeiro
authors.initials: LR
authors.lastname: Correa Netto
authors.affiliation: Departamento de Materiais Odontológicos e Prótese, Universidade Estadual Paulista, São José dos Campos, SP, Brazil.
authors.forename: Alexandre Luiz Souto
authors.initials: AL
authors.lastname: Borges
authors.affiliation: Laboratório Analítico de Biomateriais Restauradores, Faculdade de Odontologia, Universidade Federal Fluminense, Niterói, RJ, Brazil.
authors.forename: Heloisa Bailly
authors.initials: HB
authors.lastname: Guimarães
authors.affiliation: Laboratório Analítico de Biomateriais Restauradores, Faculdade de Odontologia, Universidade Federal Fluminense, Niterói, RJ, Brazil.
authors.forename: Elis Regina Nunes de
authors.initials: ER
authors.lastname: Almeida
authors.affiliation: Laboratório Analítico de Biomateriais Restauradores, Faculdade de Odontologia, Universidade Federal Fluminense, Niterói, RJ, Brazil.
authors.forename: Laiza Tatiana
authors.initials: LT
authors.lastname: Poskus
authors.affiliation: Laboratório Analítico de Biomateriais Restauradores, Faculdade de Odontologia, Universidade Federal Fluminense, Niterói, RJ, Brazil.
authors.forename: Eduardo Moreira da
authors.initials: EM
authors.lastname: Silva
mesh_terms: D000704:Analysis of Variance; D020770:Compomers / Q000737:chemistry* / Q000627:therapeutic use; D003188:Composite Resins / Q000737:chemistry / Q000627:therapeutic use; D018772:Dental Marginal Adaptation; D003793:Dental Restoration, Permanent / Q000379:methods*; D003799:Dental Stress Analysis; D006801:Humans; D016014:Linear Models; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry* / Q000627:therapeutic use; D008855:Microscopy, Electron, Scanning; D017646:Organosilicon Compounds / Q000737:chemistry* / Q000627:therapeutic use; D058105:Polymerization; D015203:Reproducibility of Results; D019279:Resin Cements / Q000737:chemistry / Q000627:therapeutic use; D013499:Surface Properties; D013997:Time Factors
chemical_list: C438313:Clearfil SE Bond; D020770:Compomers; D003188:Composite Resins; D008689:Methacrylates; D017646:Organosilicon Compounds; D019279:Resin Cements; C544925:filtek P90; C503161:polyhedral oligomeric silsesquioxane methacrylate