Al-Turki Lulwa E, Alsulimani Osamah A, Baik Khadijah M, Othmani Haytham, Alqarni Naif M, Alqarni Abdullah A, Al-Dabbagh Raghad A
Department of Oral Maxillofacial Prosthodontics, Faculty of Dentistry, King Abdulaziz University, Jeddah, Makkah Province, Saudi Arabia.
Department of Oral Diagnostic Sciences, Faculty of Dentistry, King Abdulaziz University, Jeddah, Makkah Province, Saudi Arabia.
Clin Exp Dent Res. 2025 Jun;11(3):e70161. doi: 10.1002/cre2.70161.
To evaluate the effect of deep margin elevation (DME) and immediate dentin sealing (IDS) on the fracture strength of premolars restored with lithium disilicate inlay restorations.
Standard MOD inlays with proximal box preparations extending 3 mm apical to the cementoenamel junction were prepared on forty sound premolars (n = 10) randomly divided into four groups: inlays without DME and without IDS (G1); inlays without DME but with IDS (G2); inlays with DME but without IDS (G3); and inlays with both techniques applied (G4). Composite resin was applied incrementally to elevate the proximal cervical margin coronally to the cementoenamel junction. For immediate dentin sealing, bonding agent was applied immediately after tooth preparation. All teeth were restored with lithium disilicate inlays and, after adhesive resin cementation, specimens were thermomechanically aged for 500 cycles at 5°-55°C and then subjected to load failure testing. Failure loads and locations were recorded and analyzed using one- and two-way ANOVA with Tukey's post-hoc testing (α = 0.05). Failure modes were analyzed using descriptive statistics.
The mean fracture loads were 565.76 ± 233.22 N, 978.47 ± 394.2 N, 974.31 ± 334.7 N, and 1108.21 ± 292.41 N for G1, G2, G3, and G4, respectively. Deep margin elevation (p = 0.011) and immediate dentin sealing (p = 0.010) were associated with significantly increased fracture loads. Fracture loads were significantly lower for G1 teeth than for G2-G4 teeth, but there were no significant differences between G2, G3, and G4. G1 teeth showed 50% catastrophic and non-catastrophic failures, which increased to 60% for G2 and decreased to 20% for G3 teeth. Samples with both seals and elevation (G4) had a 60% catastrophic failure rate.
When applied individually or together, deep margin elevation and immediate dentin sealing significantly increase the fracture strength of premolars restored with indirect lithium disilicate inlays.
In the challenging setting of margin elevation, studies on the effects of immediate dentin sealing have generally been limited to evaluating marginal integrity and bond strength. The findings of this In Vitro study suggest that both deep margin elevation and immediate dentin sealing protocols are likely to improve clinical outcomes of indirect lithium disilicate inlay restorations and may be considered viable options in clinical practice.
评估深边缘提升（DME）和即时牙本质封闭（IDS）对用二硅酸锂嵌体修复的前磨牙断裂强度的影响。
在40颗健康前磨牙（n = 10）上制备标准的近中-牙合-远中（MOD）嵌体，其近中端盒状预备延伸至牙釉质牙骨质界根尖3mm处，随机分为四组：无DME且无IDS的嵌体（G1）；无DME但有IDS的嵌体（G2）；有DME但无IDS的嵌体（G3）；以及应用了两种技术的嵌体（G4）。采用复合树脂分层堆塑，将近中颈部边缘向牙釉质牙骨质界冠方提升。对于即时牙本质封闭，在牙体预备后立即应用粘结剂。所有牙齿均用二硅酸锂嵌体修复，在粘结树脂粘结后，标本在5°-55°C下进行500次热机械循环老化，然后进行加载破坏试验。记录破坏载荷和位置，并使用单因素和双因素方差分析以及Tukey事后检验（α = 0.05）进行分析。使用描述性统计分析破坏模式。
G1、G2、G3和G4组的平均断裂载荷分别为565.76±233.22N、978.47±394.2N、974.31±334.7N和1108.21±292.41N。深边缘提升（p = 0.011）和即时牙本质封闭（p = 0.010）与断裂载荷显著增加相关。G1组牙齿的断裂载荷显著低于G2 - G4组牙齿，但G2、G3和G4组之间无显著差异。G1组牙齿显示50%的灾难性和非灾难性破坏，G2组增加到60%，G3组降低到20%。同时进行封闭和边缘提升的样本（G4）的灾难性破坏率为60%。
单独或联合应用时，深边缘提升和即时牙本质封闭可显著提高用间接二硅酸锂嵌体修复的前磨牙的断裂强度。
在边缘提升这一具有挑战性的情况下，关于即时牙本质封闭效果的研究通常仅限于评估边缘完整性和粘结强度。这项体外研究的结果表明，深边缘提升和即时牙本质封闭方案都可能改善间接二硅酸锂嵌体修复的临床效果，并且在临床实践中可被视为可行的选择。
