title: The use of sodium trimetaphosphate as a biomimetic analog of matrix phosphoproteins for remineralization of artificial caries-like dentin.
abstract: OBJECTIVE
  This study examined the use of sodium trimetaphosphate (STMP) as a biomimetic analog of matrix phosphoproteins for remineralization of artificial carious-affected dentin.
  
  
  METHODS
  Artificial carious lesions with lesion depths of 300±30μm were created by pH-cycling. 2.5% hydrolyzed STMP was applied to the artificial carious lesions to phosphorylate the partially-demineralized collagen matrix. Half of the STMP-treated specimens were bonded with One-Step. The adhesive and non-adhesive infiltrated specimens were remineralized in a Portland cement-simulated body fluid system containing polyacrylic acid (PAA) to stabilize amorphous calcium phosphate as nanoprecursors. Micro-computed tomography (micro-CT) and transmission electron microscopy (TEM) were used to evaluate the results of remineralization after a 4-month period.
  
  
  RESULTS
  In absence of PAA and STMP as biomimetic analogs (control groups), there was no remineralization irrespective of whether the lesions were infiltrated with adhesive. For the STMP-treated experimental groups immersed in PAA-containing simulated body fluid, specimens without adhesive infiltration were more heavily remineralized than those infiltrated with adhesive. Statistical analysis of the 4-month micro-CT data revealed significant differences in the lesion depth, relative mineral content along the lesion surface and changes in ΔZ between the non-adhesive and adhesive experimental groups (p<0.05 for all the three parameters). TEM examination indicated that collagen degradation occurred in both the non-adhesive and adhesive control and experimental groups after 4 months of remineralization.
  
  
  CONCLUSIONS
  Biomimetic remineralization using STMP is a promising method to remineralize artificial carious lesions particularly in areas devoid of seed crystallites. Future studies should consider the incorporation of MMP-inhibitors within the partially-demineralized collagen matrix to prevent collagen degradation during remineralization.
authors.affiliation: Department of Stomatology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Liu
authors.forename: Nan
authors.initials: N
authors.lastname: Li
authors.forename: Yipin
authors.initials: Y
authors.lastname: Qi
authors.forename: Li-na
authors.initials: LN
authors.lastname: Niu
authors.forename: Sally
authors.initials: S
authors.lastname: Elshafiy
authors.forename: Jing
authors.initials: J
authors.lastname: Mao
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Breschi
authors.forename: David H
authors.initials: DH
authors.lastname: Pashley
authors.forename: Franklin R
authors.initials: FR
authors.lastname: Tay
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D040761:Biomimetic Materials / Q000627:therapeutic use*; D002118:Calcium / Q000737:chemistry; D002130:Calcium Phosphates / Q000737:chemistry; D002327:Cariostatic Agents / Q000627:therapeutic use*; D003094:Collagen / Q000187:drug effects / Q000648:ultrastructure; D003188:Composite Resins / Q000737:chemistry; D003731:Dental Caries / Q000188:drug therapy* / Q000473:pathology; D003738:Dental Cements / Q000737:chemistry; D003804:Dentin / Q000187:drug effects* / Q000648:ultrastructure; D017220:Dentin-Bonding Agents / Q000737:chemistry; D016326:Extracellular Matrix Proteins / Q000627:therapeutic use*; D006801:Humans; D006878:Hydroxides / Q000737:chemistry; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D046529:Microscopy, Electron, Transmission; D008903:Minerals / Q000032:analysis; D010750:Phosphoproteins / Q000627:therapeutic use*; D011122:Polyphosphates / Q000627:therapeutic use*; D012464:Saliva, Artificial / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry; D013997:Time Factors; D017001:Tooth Demineralization / Q000188:drug therapy / Q000473:pathology; D014089:Tooth Remineralization / Q000379:methods*; D055114:X-Ray Microtomography
chemical_list: D000180:Acrylic Resins; C103506:Bis-GMA, BPDM, HEMA dental-bonding resin; D002130:Calcium Phosphates; D002327:Cariostatic Agents; D003188:Composite Resins; D003738:Dental Cements; D017220:Dentin-Bonding Agents; D016326:Extracellular Matrix Proteins; D006878:Hydroxides; D008689:Methacrylates; D008903:Minerals; D010750:Phosphoproteins; D011122:Polyphosphates; D012464:Saliva, Artificial; C006903:carbopol 940; D012822:Silicon Dioxide; D003094:Collagen; C031356:hydroxide ion; C020243:calcium phosphate; C009293:trimetaphosphoric acid; D002118:Calcium