Saad Naser Ahmed, Safwat Mustafa Dena, Ezzeldin Mohamed Dina
Masters Clinical Esthetic Dentistry, Ain Shams University, Cairo, Egypt.
Operative Dentistry Department, Faculty of Dentistry, Ain Shams University, Cairo, Egypt.
BMC Oral Health. 2025 Sep 19;25(1):1415. doi: 10.1186/s12903-025-06790-w.
This study assessed the fracture resistance of upper premolars based on the placement technique of giomer restoration in MOD cavities.
Seventy sound maxillary premolars were divided into five groups (n=14). A standardized MOD cavity was prepared in each tooth (2 mm buccolingual width, 2±0.2 mm central floor depth, and 4±0.2 mm proximal depth). Teeth were assigned to four experimental groups: Group I received Packable material (Beautifil II LS, Shofu Inc, Japan) applied in 2mm increments; Group II received Injectable material (Beautifil Flow Plus X, Shofu); Group III received a packable bulk-fill variant (Beautifil-Bulk Restorative Packable); and Group IV received flowable bulk-fill material (Beautifil-Bulk Flowable, Shofu), each followed by a 2mm occlusal capping layer. A fifth group of intact premolars served as the control. All specimens were embedded in self-cure acrylic resin blocks with simulated periodontal ligaments at temperatures ranging from 5 to 55°C, utilizing a thermocycling machine (SD Mechatronic Thermocycler, Germany). Fracture resistance was assessed using a universal testing machine (Instron 3345 Series, UK) at 1 mm/min crosshead speed. Data were analyzed using One-way ANOVA, followed by Tukey's post hoc test. The level of statistical significance was set at p<0.05.
The results indicated a significant difference in fracture resistance across groups (p<0.001). The control group exhibited the highest strength (935.12±114.52 N), followed by the Packable (926.79±229.36 N) and Injectable groups (923.29±110.28 N), with no significant differences. In contrast, the Bulk-Restorative and Bulk-Flowable groups had the lowest strengths (684.20±163.60 N and 616.08±132.54 N, respectively). Post hoc comparison showed significantly lower fracture resistance values in the bulk-restorative and bulk-flowable groups (p<0.001).
Incremental placement of packable or injectable giomers restored fracture resistance to levels comparable to sound teeth, while bulk-fill techniques yielded inferior outcomes.
Clinicians frequently opt for bulk-fill restorative materials due to their efficiency and user-friendliness compared to traditional incremental layering techniques. However, evidence regarding the fracture resistance of giomers placed via different techniques remains limited. Injectable giomers represent a viable alternative, offering superior handling and precise adaptation while maintaining favorable mechanical properties. This study provides critical insights into optimizing placement strategies to balance clinical efficiency and biomechanical performance.
本研究基于玻璃离子复合体修复材料在MOD洞型中的充填技术，评估上颌前磨牙的抗折性能。
选取70颗健康的上颌前磨牙，分为五组（每组n = 14）。为每颗牙齿制备标准化的MOD洞型（颊舌径2mm，髓室底中央深度2±0.2mm，邻面深度4±0.2mm）。将牙齿分为四个试验组：第一组使用可压实材料（日本松风公司的Beautifil II LS），每次增量2mm充填；第二组使用可注射材料（松风公司的Beautifil Flow Plus X）；第三组使用可压实型大块充填材料（Beautifil - Bulk Restorative Packable）；第四组使用可流动型大块充填材料（松风公司的Beautifil - Bulk Flowable），每组充填后均覆盖2mm的咬合面封闭层。第五组完整的前磨牙作为对照组。所有标本嵌入带有模拟牙周韧带的自凝丙烯酸树脂块中，在5至55°C的温度范围内使用热循环仪（德国SD Mechatronic Thermocycler）进行热循环处理。使用万能材料试验机（英国Instron 3345系列）以1mm/min的横梁速度评估抗折性能。数据采用单因素方差分析，随后进行Tukey事后检验。设定统计学显著性水平为p<0.05。
结果表明各组间抗折性能存在显著差异（p<0.001）。对照组表现出最高强度（935.12±114.52N），其次是可压实组（926.79±229.36N）和可注射组（923.29±110.28N），差异无统计学意义。相比之下，大块修复组和大块流动组强度最低（分别为684.20±163.60N和616.08±132.54N）。事后比较显示，大块修复组和大块流动组的抗折性能值显著较低（p<0.001）。
可压实或可注射型玻璃离子复合体修复材料的分层充填可使抗折性能恢复到与健康牙齿相当的水平，而大块充填技术的效果较差。
与传统的分层充填技术相比，临床医生常因大块充填修复材料的高效性和易用性而选择使用。然而，关于不同技术放置玻璃离子复合体修复材料后的抗折性能的证据仍然有限。可注射型玻璃离子复合体修复材料是一种可行的替代方案，在保持良好机械性能的同时，具有更好的操作性和精确贴合性。本研究为优化充填策略以平衡临床效率和生物力学性能提供了关键见解。
