Abstract This in vitro study evaluated the volumetric change (VC) and gap formation (GF) in Class V composite restorations after light-curing and aging. Thirty-six extracted human premolars were used. Standardized Class V cavities (3 mmx3 mmx1.5 mm) were prepared. G-Premio Bond was applied. The teeth were randomly assigned into six groups (n = 6): Group FZ: Filtek Z250(microhybrid), Group SP: SDR Plus Bulk Fill Flowable (low-viscosity bulk-fill), Group EB: Estelite Bulk Fill Flow (low-viscosity bulk-fill), Group GI: G-aenial Universal Injectable (highly-filled low-viscosity), Group AF: Admira Fusion (ormocer), Group SX: Solare X (nanohybrid). Each specimen was scanned four times with micro-CT (SkyScan 1174v2, Belgium): after cavity preparation, before and after light-curing, and after aging. The VC (%) and GF (mm3) parameters were quantified and analysed. Then, VC after light-curing was verified with AcuVol video image analyser (n = 6). The specimens were submitted to 10,000 thermocycles (5–55 °C) and 100,000 load cycles (50N). The data were statistically analysed using the Kruskal-Wallis, Wilcoxon and Dunn tests (p < 0.05). After light-curing, Group AF and FZ showed significantly lower VC than Group GI. Group GI showed significantly higher total GF than Group AF, EB, FZ and SX. Group GI showed significantly higher GF than Group AF, EB and FZ in cervical region. After aging, a significant increase in the volume of the gap (VG) in cervical region was found for Group FZ and GI (p < 0.05). After light-curing, ormocer and microhybrid composites exhibited lower VC and GF than highly-filled low-viscosity composites. After aging, an increase in VG was observed for microhybrid and highly-filled low-viscosity composites for cervical region.

中文翻译：

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V 类复合修复体中的体积变化和间隙形成：显微 CT 分析

摘要 这项体外研究评估了光固化和老化后 V 类复合材料修复体的体积变化 (VC) 和间隙形成 (GF)。使用了 36 颗提取的人类前磨牙。准备了标准化的 V 级腔（3 mmx3 mmx1.5 mm）。应用了 G-Premio 债券。牙齿被随机分为六组（n = 6）：FZ 组：Filtek Z250（微混合），SP 组：SDR Plus Bulk Fill Flowable（低粘度散装填充），EB 组：Estelite Bulk Fill Flow（低-粘度散装填充），GI 组：G-aenial Universal Injectable（高填充低粘度），AF 组：Admira Fusion（ormocer），SX 组：Solare X（纳米混合）。每个样品用显微 CT（SkyScan 1174v2，比利时）扫描四次：腔体制备后、光固化前后和老化后。VC (%) 和 GF (mm3) 参数被量化和分析。然后，使用 AcuVol 视频图像分析仪 (n = 6) 验证光固化后的 VC。试样经受 10,000 次热循环 (5–55 °C) 和 100,000 次载荷循环 (50N)。使用 Kruskal-Wallis、Wilcoxon 和 Dunn 检验对数据进行统计分析 (p < 0.05)。光固化后，AF 组和 FZ 组的 VC 显着低于 GI 组。GI 组的总 GF 显着高于 AF、EB、FZ 和 SX 组。GI组在颈部区域的GF显着高于AF组、EB组和FZ组。老化后，发现 FZ 组和 GI 组宫颈区域的间隙体积 (VG) 显着增加 (p < 0.05)。光固化后，ormocer 和微杂化复合材料的 VC 和 GF 低于高填充低粘度复合材料。老化后，