Effects of hexafluorosilicate on the precipitate composition and dentine tubule occlusion by calcium phosphate.
OBJECTIVE
To improve the calcium phosphate precipitation (CPP) method for the occlusion of dentine tubules with calcium phosphate, the addition of calcium hexafluorosilicate (CaSiF6) to CPP solution was evaluated in vitro with respect to its occluding capacity and the composition of the precipitate.


METHODS
The occlusion of dentine tubules was evaluated by SEM observations and by measurements of dentine permeability. The composition of the precipitate was determined by measuring the calcium to phosphorus (Ca/P) ratio of the precipitate in dentine tubules by energy dispersive X-ray spectroscopy (EDS).


RESULTS
The addition of CaSiF6 to the CPP solution resulted in an increase of the Ca/P ratio in the precipitate not only on the dentine surface but also inside the dentine tubules; indicating that the precipitate became more apatitic in nature. The addition of CaSiF6 had no effect on occluding capacity in terms of measurements of dentine permeability or SEM observations. Dentine permeability decreased to approximately 4% of pretreatment values and the dentine tubules were occluded for approximately 10-15 microns from the dentine surface.


CONCLUSIONS
It is concluded that the addition of CaSiF6 to CPP solution was desirable, since it provided a more apatitic precipitate in the dentine tubules, not only on the dentine surface but also inside the tubules, and there were no drawbacks with respect to its occluding capacity.
Kawasaki
A
A
Department of Conservative Dentistry, School of Dentistry, Tokushima University, Japan.
Ishikawa
K
K
Suge
T
T
Yoshiyama
M
M
Asaoka
K
K
Ebisu
S
S
D001031:Apatites / Q000737:chemistry; D002118:Calcium / Q000032:analysis; D002130:Calcium Phosphates / Q000737:chemistry*; D011232:Chemical Precipitation; D003804:Dentin / Q000737:chemistry / Q000187:drug effects* / Q000648:ultrastructure; D003806:Dentin Permeability / Q000187:drug effects; D017886:Durapatite / Q000737:chemistry; D004577:Electron Probe Microanalysis; D005459:Fluorides / Q000737:chemistry / Q000494:pharmacology*; D006801:Humans; D008855:Microscopy, Electron, Scanning; D010758:Phosphorus / Q000032:analysis; D017640:Silicates / Q000737:chemistry / Q000494:pharmacology*; D012824:Silicic Acid / Q000737:chemistry / Q000494:pharmacology*
D001031:Apatites; D002130:Calcium Phosphates; D017640:Silicates; C485828:alpha-tricalcium phosphate; C485830:tetracalcium phosphate; D012824:Silicic Acid; C004832:hexafluorosilicate; D010758:Phosphorus; C485838:calcium phosphate, monobasic, anhydrous; D017886:Durapatite; C020243:calcium phosphate; C485829:calcium phosphate, dibasic, anhydrous; D005459:Fluorides; D002118:Calcium