title: Proteins, pathogens, and failure at the composite-tooth interface.
abstract: In the United States, composites accounted for nearly 70% of the 173.2 million composite and amalgam restorations placed in 2006 (Kingman et al., 2012), and it is likely that the use of composite will continue to increase as dentists phase out dental amalgam. This trend is not, however, without consequences. The failure rate of composite restorations is double that of amalgam (Ferracane, 2013). Composite restorations accumulate more biofilm, experience more secondary decay, and require more frequent replacement. In vivo biodegradation of the adhesive bond at the composite-tooth interface is a major contributor to the cascade of events leading to restoration failure. Binding by proteins, particularly gp340, from the salivary pellicle leads to biofilm attachment, which accelerates degradation of the interfacial bond and demineralization of the tooth by recruiting the pioneer bacterium Streptococcus mutans to the surface. Bacterial production of lactic acid lowers the pH of the oral microenvironment, erodes hydroxyapatite in enamel and dentin, and promotes hydrolysis of the adhesive. Secreted esterases further hydrolyze the adhesive polymer, exposing the soft underlying collagenous dentinal matrix and allowing further infiltration by the pathogenic biofilm. Manifold approaches are being pursued to increase the longevity of composite dental restorations based on the major contributing factors responsible for degradation. The key material and biological components and the interactions involved in the destructive processes, including recent advances in understanding the structural and molecular basis of biofilm recruitment, are described in this review. Innovative strategies to mitigate these pathogenic effects and slow deterioration are discussed.
authors.affiliation: Department of Mechanical Engineering Bioengineering Research Center pspencer@ku.edu.
authors.forename: P
authors.initials: P
authors.lastname: Spencer
authors.affiliation: Bioengineering Research Center.
authors.forename: Q
authors.initials: Q
authors.lastname: Ye
authors.affiliation: Bioengineering Research Center Department of Civil Engineering, University of Kansas, Lawrence, KS, USA.
authors.forename: A
authors.initials: A
authors.lastname: Misra
authors.affiliation: School of Dentistry of São José dos Campos, UNESP, Univ Estadual Paulista, São José dos Campos, SP, Brazil.
authors.forename: S E P
authors.initials: SE
authors.lastname: Goncalves
authors.affiliation: Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, KS, USA.
authors.forename: J S
authors.initials: JS
authors.lastname: Laurence
mesh_terms: D001422:Bacterial Adhesion / Q000502:physiology; D018441:Biofilms; D003188:Composite Resins / Q000737:chemistry*; D001840:Dental Bonding; D003764:Dental Materials / Q000737:chemistry*; D044622:Dental Pellicle / Q000382:microbiology; D019232:Dental Restoration Failure; D006801:Humans; D012471:Salivary Proteins and Peptides / Q000493:pharmacokinetics*; D013295:Streptococcus mutans / Q000502:physiology*; D014070:Tooth / Q000378:metabolism / Q000382:microbiology*; D017001:Tooth Demineralization / Q000382:microbiology
chemical_list: D003188:Composite Resins; D003764:Dental Materials; D012471:Salivary Proteins and Peptides
keywords: Streptococcus mutans; biofilm; dentin bonding agents; esterases; gp340; methacrylate