title: Unique functions of hydroxyapatite with mutans streptococci adherence.
abstract: OBJECTIVE
  Hydroxyapatite (HA) is used as a construction material for artificial supplementation of enamel tooth surfaces to improve oral hygiene. This study examined in vitro HA interactions with mutans streptococci (MS) and bacterial adherence to small (nanosize) crystal form of HA beads having a protean hexagonal structure. The adsorption and physical effects of HA employed in vivo is also described.
  
  
  METHODS
  [3H-thymidine]-labeled streptococci were incubated with HA noncoated or coated with salivary components or salivary agglutinin peptide (SRCRP2), a receptor for streptococcal surface proteins. Bacterial adhesion activities on HA were measured by uptake of [3H-thymidine]. Application of HA paste in an individual tray was tried on the tooth surface, and its effects on the colony ratio of MS/total streptococci (TS) in saliva were analyzed by culture technique.
  
  
  RESULTS
  The adhesion assay showed that the binding of streptococci to HA was inhibited by coating with salivary components, whereas coating with SRCRP2 had nearly no influence on binding with or without Ca+. Further, treatment with HA decreased the adherence of Streptococci mutans to roughened enamel surfaces by one-third. In vivo application of a HA dentifrice to individual teeth demonstrated that the colony number ratio of MS/TS slowly decreased.
  
  
  CONCLUSIONS
  MS adhesion to HA was restricted by both salivary components, except for SRCRP2, and the physical effects of HA; in addition, the material itself has a unique effect for removing MS from the oral cavity.
authors.affiliation: Central Research and Development, Sangi, Tokyo, Japan.
authors.forename: Tadayoshi
authors.initials: T
authors.lastname: Arakawa
authors.forename: Takeshi
authors.initials: T
authors.lastname: Fujimaru
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Ishizak
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Takeuchi
authors.forename: Masato
authors.initials: M
authors.lastname: Kageyama
authors.forename: Takuji
authors.initials: T
authors.lastname: Ikemi
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Hanada
authors.forename: Haruo
authors.initials: H
authors.lastname: Watanabe
authors.forename: Hidenobu
authors.initials: H
authors.lastname: Senpuku
mesh_terms: D018829:Adhesins, Bacterial / Q000737:chemistry / Q000378:metabolism*; D000328:Adult; D000595:Amino Acid Sequence; D000704:Analysis of Variance; D001422:Bacterial Adhesion; D003743:Dental Enamel / Q000382:microbiology; D003802:Dentifrices / Q000737:chemistry / Q000494:pharmacology*; D017886:Durapatite / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D008969:Molecular Sequence Data; D053758:Nanoparticles; D011485:Protein Binding; D012463:Saliva / Q000382:microbiology; D012471:Salivary Proteins and Peptides / Q000378:metabolism*; D013295:Streptococcus mutans / Q000187:drug effects* / Q000502:physiology*; D013499:Surface Properties
chemical_list: D018829:Adhesins, Bacterial; D003802:Dentifrices; D012471:Salivary Proteins and Peptides; C068465:salivary agglutinin receptor, Streptocococcus; D017886:Durapatite