Javed Faiza, Tewari Rajendra Kumar, Alam Sharique, Husain Shahid, Hasan Faisal
Department of Conservative Dentistry and Endodontics, Dr. Ziauddin Ahmad Dental College and Hospital, Aligarh Muslim University, Aligarh, Uttar Pradesh, India.
Department of Physics, Aligarh Muslim University, Aligarh, Uttar Pradesh, India.
Clin Oral Investig. 2025 Sep 2;29(9):437. doi: 10.1007/s00784-025-06510-2.
This in vitro study aims to compare the effect of different light curing modes and curing times on the degree of conversion (DC) and microhardness (MH) of three different bulk fill composites at two different depths.
A total of 224 cylindrical specimens (4 mm height, 6 mm diameter) were prepared using four composites: SDR Plus, Ever X Posterior (EXP), Beautifil Bulk Restorative (BBR), and Tetric N Ceram (TNC). Each material group (n = 56) was subdivided into four curing subgroups based on light-curing mode (Low Power or High Power) and exposure time (20-30 s). Following curing, all samples were stored at 37 °C for 24 h. From each subgroup, seven specimens were allocated for DC testing using Raman spectroscopy and seven for MH testing using the Vickers microhardness test.
All the materials achieved acceptable (> 80%) bottom-to-top Vickers hardness ratio in high power (HP) mode for both curing times. However, in the low power (LP) mode, EXP could not achieve this ratio at 20 s and BBR failed to achieve this ratio in both curing times. BBR could not achieve an acceptable DC (> 55%) in both curing modes and both curing times. EXP did not demonstrate acceptable DC in LP mode at 20 s curing time, while SDR showed acceptable DC in both curing modes and both curing times.
Compliance with manufacturers' instructions yielded acceptable outcomes in most cases. Each bulk fill material has different requirements pertaining to curing intensity and time to achieve desirable microhardness and degree of conversion. Clinicians should be aware of the curing protocol for the specific bulk fill materials.
BBR consistently exhibited low degrees of conversion, even when the applied energy density exceeded the manufacturer's recommended levels. Further research is warranted to establish optimized curing protocols for giomer-based composites and to investigate the long-term impact of the degree of conversion on the mechanical properties and clinical durability of these restorations.
本体外研究旨在比较不同光固化模式和固化时间对两种不同深度下三种不同的大块充填复合树脂的转化率（DC）和显微硬度（MH）的影响。
使用四种复合树脂制备了总共224个圆柱形试件（高4毫米，直径6毫米）：SDR Plus、Ever X Posterior（EXP）、Beautifil Bulk Restorative（BBR）和Tetric N Ceram（TNC）。每个材料组（n = 56）根据光固化模式（低功率或高功率）和照射时间（20 - 30秒）细分为四个固化亚组。固化后，所有样品在37°C下储存24小时。从每个亚组中，分配七个试件用于使用拉曼光谱进行DC测试，七个用于使用维氏显微硬度测试进行MH测试。
在两种固化时间下，所有材料在高功率（HP）模式下均实现了可接受的（> 80%）从底部到顶部的维氏硬度比。然而，在低功率（LP）模式下，EXP在20秒时未达到该比例，BBR在两种固化时间下均未达到该比例。BBR在两种固化模式和两种固化时间下均未达到可接受的DC（> 55%）。EXP在LP模式下20秒固化时间时未表现出可接受的DC，而SDR在两种固化模式和两种固化时间下均表现出可接受的DC。
在大多数情况下，遵循制造商的说明可产生可接受的结果。每种大块充填材料对于固化强度和时间有不同要求，以实现所需的显微硬度和转化率。临床医生应了解特定大块充填材料的固化方案。
即使施加的能量密度超过制造商推荐水平，BBR始终表现出低转化率。有必要进行进一步研究，以建立基于聚硅氧烷复合树脂的优化固化方案，并研究转化率对这些修复体的机械性能和临床耐久性的长期影响。
