Objectives

To evaluate optical properties (color and translucency) of ‘sandwich’ restorations of resin-based composites and esthetically unfavorable dentin restoratives.

Methods

Cylindrical ‘dentin’ specimens (8 mm in diameter and 2 mm thick, N = 5/group) were prepared using EverX Posterior (GC), Biodentine (Septodont), experimental hydroxyapatite (HAP) or conventional composites (Gradia Direct Posterior, GC; Filtek Z250 and Filtek Z500, 3M ESPE). Capping ‘enamel’ layers were prepared using composites (Gradia Direct Posterior, Filtek Z250 or Z550) of A1 or A3 shade and the following thickness: 0.6, 1 or 2 mm. Color (ΔE) and translucency parameter (TP) were determined using a spectrophotometer (VITA Easyshade Advance 4.0, VITA Zahnfabrik). Data were statistically analyzed using analysis of variance with Tukey’s post-hoc tests (α = 0.05).

Results

TP was greatly affected by layer thickness, whilst ΔE depended on shade and layer thickness of the capping composite. HAP and Biodentine showed significantly lower TP and higher ΔE (deviation from ‘ideal white’) than composites (p < 0.05). Greater TP was seen in EverX_composite groups than in corresponding control groups of the same shade and thickness. TP of composites combined with Biodentine or HAP was below 2, lower than the corresponding control groups (p < 0.05). Within-group differences of ΔE were greatest in HAP_composite groups. EverX_Gradia and EverX_FiltekZ250 combinations showed the most comparable ΔE with the control groups.

Significance

A 2 mm thick layer of composite covering dentin restoratives with unfavorable esthetics is recommended for a final ‘sandwich’ restoration that is esthetically comparable to a conventional, mono-composite control restoration.

中文翻译：

---

不同牙本质修复剂对复合修复体的光学性能的影响

目标

评估树脂基复合材料和美学上不利的牙本质修复剂的“三明治”修复体的光学性能（颜色和半透明性）。

方法

使用EverX后路（GC），Biodentine（Septodont），实验性羟基磷灰石（HAP）或常规复合材料（Gradia Direct Posterior，GC; Filtek Z250和Filtek Z500，3M ESPE）。使用A1或A3阴影和以下厚度：0.6、1或2 mm的复合材料（Gradia Direct Posterior，Filtek Z250或Z550）制备封盖的“搪瓷”层。使用分光光度计（VITA Easyshade Advance 4.0，VITA Zahnfabrik）确定颜色（ΔE）和半透明参数（TP）。使用Tukey事后检验（α  = 0.05）使用方差分析对数据进行统计分析。

结果

TP很大程度上受层厚的影响，而ΔE则取决于封端复合材料的阴影和层厚。与复合材料相比，HAP和Biodentine显示出更低的TP和更高的ΔE（偏离“理想的白色”）（p <0.05）。在EverX_composite组中看到的TP比在相同阴影和厚度的相应对照组中更高。结合Biodentine或HAP的复合材料的TP低于2，低于相应的对照组（p <0.05）。在HAP_composite组中，ΔE的组内差异最大。EverX_Gradia和EverX_FiltekZ250组合显示出与对照组最可比的ΔE。

意义

对于最终的“三明治”修复，建议使用2 mm厚的复合材料覆盖牙本质修复剂并具有不利的美学效果，这在美学上可以与传统的单复合材料控制修复相媲美。