Department of Restorative Dental Sciences, School of Dentistry, Jazan University, Saudi Arabia.
School of Dentistry, University of Michigan, Ann Arbor, Michigan, USA.
Am J Dent. 2022 Jun;35(2):128-132.
To evaluate microleakage measurements using micro-CT in comparison to dye tracers in Class 2 bulk-fill composite restorations with two adhesive techniques.
60 sound molars were prepared with Class 2 cavities having cervical margins in enamel (mesial) and in dentin (distal) and restored with Filtek Bulk Fill, using either a self-etch or total-etch technique. All teeth were thermo-cycled between 5°C and 55°C for 800 cycles and randomly exposed to three tracer dyes: 2% methylene blue, 0.5% basic fuchsin or 50% silver nitrate solutions. Teeth were sectioned mesial-distal and depth of tracer penetration was measured as a ratio of dye penetration from the cavosurface divided by total depth of the cervical floor. The silver nitrate subgroup was micro-CT scanned prior to sectioning, evaluated in 3D serial sections, and calculated volumetrically.
Analysis of ratios for dye tracer penetration showed significantly lower values for methylene blue (0.120). Micro-CT values calculated in 3D as volume (mm³) were significantly greater in enamel for self-etch (0.060) compared to total-etch (0.020). Micro-CT volumetric analysis showed better discrimination with significantly greater leakage in enamel margins using the self-etch adhesive.
Based on this in vitro study of microleakage, micro-CT volumetric evaluation in serial digital sections improves discrimination and represents a more reliable estimate of true microleakage. In vitro study of microleakage is most useful in comparing adhesive products, but clinical application of the data is questionable.
使用微计算机断层扫描（micro-CT）评估与染料示踪剂相比，两种粘接技术在 2 类大体积充填复合修复体中的微渗漏测量值。
60 颗健康磨牙制备 2 类窝洞，颈缘位于釉质（近中）和牙本质（远中），用 Filtek Bulk Fill 以自酸蚀或全酸蚀技术进行修复。所有牙齿在 5°C 和 55°C 之间进行 800 次热循环，并随机暴露于三种示踪染料：2%亚甲蓝、0.5%碱性品红或 50%硝酸银溶液。牙齿沿近远中方向进行切割，测量示踪剂渗透深度，计算为从釉牙骨质界到颈缘下总深度的染料渗透比值。硝酸银亚组在切割前进行 micro-CT 扫描，在 3D 连续切片中进行评估，并进行体积计算。
示踪染料渗透比值分析显示，亚甲蓝（0.120）的渗透值明显较低。3D 体积（mm³）计算显示，自酸蚀（0.060）比全酸蚀（0.020）在釉质中计算的微 CT 值更大。微 CT 体积分析显示，自酸蚀黏接剂的牙釉质边缘微渗漏具有更好的区分度，渗漏明显更大。
基于这项微渗漏的体外研究，连续数字切片的 micro-CT 体积评估提高了区分度，代表了更可靠的真实微渗漏估计。体外微渗漏研究最有助于比较黏接产品，但数据的临床应用值得怀疑。
