Effect of a resin-modified glass-ionomer with calcium on enamel demineralization inhibition: an in vitro study

Abstract We assessed the effect of a new coating material based on resin-modified glass-ionomer with calcium (Ca) in inhibiting the demineralization of underlying and adjacent areas surrounding caries-like lesions in enamel. The measures used were surface hardness (SH) and cross-sectional hardness (CSH). Thirty-six bovine enamel specimens (3 × 6 × 2 mm) were randomly allocated into three groups (n = 12): No treatment (NT); resin-modified glass-ionomer with Ca (Clinpro XT Varnish, 3M ESPE) (CL), and fluoride varnish (Duraphat, Colgate) (DU). The specimens were subjected to alternated immersions in demineralizing (6 h) and remineralizing solutions (18 h) for 7 days. SH measurements were conducted at standard distances of 150, 300, and 450 µm from the treatment area. CSH evaluated the mean hardness profile over the depth of the enamel surface and at standard distances from the materials. The energy-dispersive X-ray spectroscopy analysis was conducted to evaluate the demineralization bands created on the sublayer by % of calcium (Ca), phosphorus (P), and fluoride (F). Ca/P weight ratio was also calculated. Based on SH and CSH measurements, there was no difference between groups at the distances 150 µm (p = 0.882), 300 µm (p = 0.995), and 450 µm (p = 0.998). Up to 50 µm depth (at 150 µm from the treatment area), CL showed better performance than DU ( p< 0.05). NT presented higher loss of Ca and P than CL and DU (p < 0.05). There was no significant difference in the % of F ion among the three groups. The new coating material was similar to F varnish in attenuating enamel demineralization.

摘要 本研究评估了一种新型含钙（Calcium, Ca）树脂改性玻璃离子体（resin-modified glass-ionomer with Ca）涂层材料，对牙釉质龋样病变周围区域及其下方组织的脱矿进程的抑制作用。本研究采用表面硬度（surface hardness, SH）与截面硬度（cross-sectional hardness, CSH）作为检测指标。将36件尺寸为3×6×2 mm的牛牙釉质标本随机分为3组（每组n=12）：空白对照组（No treatment, NT）、含钙树脂改性玻璃离子体涂层组（resin-modified glass-ionomer with Ca，商品名Clinpro XT Varnish，3M ESPE出品，简称CL）以及氟保护漆组（fluoride varnish，商品名Duraphat，高露洁Colgate出品，简称DU）。将标本交替浸没于脱矿液（6小时）与再矿化液（18小时）中，持续7天。在距处理区域150、300及450 μm的标准检测位置开展表面硬度检测；截面硬度检测则用于评估牙釉质表面深层以及距修复材料标准距离处的平均硬度分布。采用能量色散X射线光谱（energy-dispersive X-ray spectroscopy）分析，通过检测钙（Ca）、磷（P）及氟（F）的百分比，评估亚表层形成的脱矿带，同时计算钙磷重量比。基于表面硬度与截面硬度检测结果，在150 μm（p=0.882）、300 μm（p=0.995）及450 μm（p=0.998）处，各组间均无显著差异。在距处理区域150 μm处的50 μm深度范围内，CL组的脱矿抑制效果优于DU组（p<0.05）。NT组的钙、磷流失量显著高于CL组与DU组（p<0.05）。三组的氟离子百分比无显著差异。该新型涂层材料在抑制牙釉质脱矿方面与氟保护漆效果相当。