Influence of calcium phosphates added to mucin-based saliva substitutes on bovine dentin.
OBJECTIVE
Remineralization of dentin by mucin-containing saliva substitutes might be inhibited by sialic acids bound to mucin, which are known to complex calcium. Thus, the aim of this investigation was to evaluate the effects of various mucin-containing solutions, differing in calcium phosphate concentrations, to be used as saliva substitutes on demineralized bovine dentin in vitro.


METHODS
Bovine specimens (153) were embedded in epoxy resin, polished (4,000 grit), and partly covered with nail varnish (control of sound dentin). After demineralization for 14 days (pH 5.5), the specimens (n = 9) were exposed to 14 mucin-based solutions (30 g/L) at 2 different pH values (5.5 or 6.5) and differing in saturation with respect to apatites. Two fluoride-free solutions and the commercially available saliva substitute Saliva Orthana(Orthana, Kastrup) served as controls. Differences in mineral loss (deltadeltaZ) and lesion depth (deltaLD) between the values prior to and after storage in the various solutions were evaluated from microradiographs of thin sections (100 microm).


RESULTS
The general linear model revealed an almost significant dependency on calcium for deltadeltaZ (P = .050) and a significant dependency on calcium for deltaLD (P = .037). pH influenced deltadeltaZ significantly (P < .001), whereas deltaLD was not influenced significantly (P = .169). Neither deltadeltaZ (P = .475) nor deltaLD (P = .703) were influenced significantly by phosphate.


CONCLUSIONS
Even with low concentrations of calcium and phosphates, mucin-based saliva substitutes are capable of inhibiting demineralization of bovine dentin, whereas with solutions supersaturated with respect to apatites, a remineralizing effect could be observed.
Meyer-Lückel
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Department of Operative Dentistry and Periodontology, School of Dental Medicine, Campus Benjamin Franklin, Charité-Universitätsmedizin Berlin, Germany. hendrik.meyer-lueckel@charite.de
Kielbassa
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AM
D000704:Analysis of Variance; D000818:Animals; D002130:Calcium Phosphates / Q000008:administration & dosage*; D002327:Cariostatic Agents / Q000008:administration & dosage*; D002417:Cattle; D003804:Dentin / Q000187:drug effects*; D004338:Drug Combinations; D005459:Fluorides / Q000008:administration & dosage; D006863:Hydrogen-Ion Concentration; D016014:Linear Models; D009077:Mucins / Q000008:administration & dosage* / Q000737:chemistry / Q000627:therapeutic use; D012464:Saliva, Artificial / Q000737:chemistry* / Q000627:therapeutic use; D012996:Solutions; D018709:Statistics, Nonparametric; D017001:Tooth Demineralization / Q000517:prevention & control; D014089:Tooth Remineralization / Q000379:methods*; D014993:Xylitol / Q000737:chemistry / Q000627:therapeutic use
D002130:Calcium Phosphates; D002327:Cariostatic Agents; D004338:Drug Combinations; D009077:Mucins; D012464:Saliva, Artificial; D012996:Solutions; C072342:saliva Orthana; D005459:Fluorides; D014993:Xylitol