Suge T, Ishikawa K, Kawasaki A, Yoshiyama M, Asaoka K, Ebisu S
Department of Conservative Dentistry, School of Dentistry, Tokushima University, Japan.
J Dent Res. 1995 Oct;74(10):1709-14. doi: 10.1177/00220345950740101301.
The use of a calcium phosphate precipitation method occluded dentin tubules with apatitic mineral and, thus, showed good potential for the treatment of dentin hypersensitivity. The aim of this study was to elucidate the occluding behavior of the precipitate in the oral environment. Dentin disks treated by the calcium phosphate precipitation method, and disks treated with potassium oxalate, NaF, and SrCl2 solutions, were immersed in synthetic saliva, which was regularly replenished so that ionic concentration would be maintained. Treatment of dentin disks by the calcium phosphate precipitation method immediately reduced dentin permeability to 6 +/- 8%. When the disk was immersed in synthetic saliva, dentin permeability remained low, even seven days after immersion. Scanning electron microscopic observation showed no distinct boundary line between the precipitate and intertubular dentin; this indicated further mineralization on the precipitate. Potassium oxalate treatment also reduced the dentin permeability to 8 +/- 3%. However, the dentin permeability gradually but steadily increased with immersion time, reaching 39 +/- 14% at seven days. To elucidate the mechanism underlying dentin permeability changes in synthetic saliva, we immersed the precipitates, i.e., apatitic mineral and calcium oxalate, in a fixed volume of synthetic saliva. When calcium oxalate was immersed in synthetic saliva, there was a large concentration of oxalate ions, indicating dissolution of the calcium oxalate; this phenomenon was ascribed to the increase in dentin permeability. In contrast, calcium and phosphate ions decreased when apatitic powder, the precipitate formed by the calcium phosphate precipitation method, was immersed in synthetic salvia. The decrease in the calcium and phosphate ions in synthetic saliva indicated further precipitation of calcium phosphate on the apatitc precipitate.(ABSTRACT TRUNCATED AT 250 WORDS)
采用磷酸钙沉淀法可使磷灰石矿物堵塞牙本质小管，因此在治疗牙本质过敏方面显示出良好的潜力。本研究的目的是阐明沉淀物在口腔环境中的堵塞行为。将经磷酸钙沉淀法处理的牙本质片以及用草酸钾、氟化钠和氯化锶溶液处理的牙本质片浸入人工唾液中，并定期补充人工唾液以维持离子浓度。用磷酸钙沉淀法处理牙本质片后，牙本质通透性立即降至6±8%。当牙本质片浸入人工唾液中时，即使在浸入7天后，牙本质通透性仍保持较低水平。扫描电子显微镜观察显示沉淀物与管间牙本质之间没有明显的分界线；这表明沉淀物上有进一步的矿化作用。草酸钾处理也使牙本质通透性降至8±3%。然而，牙本质通透性随着浸入时间逐渐但稳步增加，在7天时达到39±14%。为了阐明人工唾液中牙本质通透性变化的潜在机制，我们将沉淀物，即磷灰石矿物和草酸钙，浸入固定体积的人工唾液中。当草酸钙浸入人工唾液中时，草酸根离子浓度很高，表明草酸钙溶解；这种现象归因于牙本质通透性的增加。相反，当用磷酸钙沉淀法形成的沉淀物磷灰石粉末浸入人工唾液中时，钙和磷酸根离子减少。人工唾液中钙和磷酸根离子的减少表明磷酸钙在磷灰石沉淀物上进一步沉淀。（摘要截短至250字）
