Department of Fixed Prosthodontics, Faculty of Dentistry, Damascus University, Damascus, the Syrian Arab Republic.
Swiss Dent J. 2022 Jul 11;132(7-8):482-489. doi: 10.61872/sdj-2022-07-08-01. Epub 2022 Apr 28.
This study aimed to evaluate the effect of immediate dentin sealing (IDS) on the fracture strength of ceramic onlays when compared with delayed dentin sealing (DDS). Twenty extracted human maxillary premolars were randomly divided into 2 groups according to the dentin sealing technique (n=10). A standardized mesio-occlusal-distal cavity was prepared with reduction of the palatal cusp. The dentin surfaces of the IDS group were immediately sealed after finishing the preparation (before taking impressions, temporization, and 14-day storage at 37°C) using a bonding system (ALL-BOND 3®, ALL-BOND 3® RESIN) and flowable composite (Te-Econom Flow). Impressions were made and temporary restorations were fabricated using PRO-V FILL®. The wax patterns were milled and the onlays were fabricated by heat-pressing technique (IPS e.max Press). After bonding the final restorations with resin cement (Variolink N), the specimens were thermocycled. Fracture strength was measured using a universal testing machine (Testometric M350-10KN) at 1 mm/min until failure occurred. Student's t-test was used to evaluate the results of the fracture strength test. The failure mode was examined using a stereomicroscope. The mean fracture strength in the IDS group (1335 ± 335 N) was statistically significantly higher than that for the DDS group (931 ± 274 N) (p < 0.05). Fracture of the restoration with a small portion of the tooth was the most frequent mode of failure. Within the limitation of this in vitro study, there was an improvement in the fracture strength of ceramic onlays with the use of IDS. However, the ceramic onlays were strong enough to withstand the physiological mastication force in both groups.
本研究旨在评估即刻牙本质密封（IDS）与延迟牙本质密封（DDS）相比对陶瓷嵌体断裂强度的影响。将 20 颗上颌前磨牙随机分为 2 组，根据牙本质密封技术（n=10）。制备标准的近中-颊-远中腔，减少腭尖。IDS 组的牙本质表面在完成制备后立即密封（在印模、临时修复和 37°C 下储存 14 天后），使用粘接系统（ALL-BOND 3®，ALL-BOND 3®RESIN）和可流动复合材料（Te-Econom Flow）。制取印模并用 PRO-V FILL®制作临时修复体。用蜡型制作蜡型，用热压技术（IPS e.max Press）制作嵌体。用树脂水门汀（Variolink N）粘接最终修复体后，对试件进行热循环。用万能试验机（Testometric M350-10KN）以 1mm/min 的速度进行断裂强度测试，直至试件失效。采用 Student t 检验评估断裂强度测试结果。用立体显微镜检查失效模式。IDS 组的平均断裂强度（1335±335N）显著高于 DDS 组（931±274N）（p<0.05）。修复体与少量牙体同时断裂是最常见的失效模式。在本体外研究的限制内，使用 IDS 可提高陶瓷嵌体的断裂强度。然而，两组陶瓷嵌体都足以承受生理咀嚼力。
