Statement of problem

The esthetics of anterior lithium disilicate restorations can be enhanced if the buccal aspect is layered with a feldspathic ceramic. However, whether fractures and chipping of this layer are a prevalent complication is unclear.

Purpose

The purpose of this retrospective study was to evaluate the incidence of incisal fracture of a specially designed lithium disilicate reinforcement of the incisal edge for indirect anterior bilayered restorations on both teeth and implants.

Material and methods

A total of 924 anterior bilayered pressed lithium disilicate restorations in 324 patients and made in one dental laboratory were delivered by 4 restorative dentists. The restorations had the palatal side of the incisal edge in monolithic lithium disilicate and the facial side in feldspathic porcelain. The restorations were evaluated for survival and the occurrence of fracture or chipping. Survival analyses were performed by using the Kaplan-Meier and log rank (Mantel-Cox) tests (α=.05).

Results

Of the 924 restorations, 798 (236 complete crowns, 562 partial restorations) were placed on teeth and 126 on implants. The mean observation time was 38 months (3 to 72 months). The survival rate was 96.5%, with 14 failures occurring. The failures were fracture after dental trauma (n=5), ceramic fracture (n=1), debonding (n=6), poor shade match (n=1), and tooth loss (n=2). Restorations in patients with parafunctional habits and endodontically treated teeth showed a significant decrease in survival rate (P=.018). No significant differences were found between the survival of restorations on teeth and implants and between complete crowns and partial restorations (P=.021). No chipping was observed on any restorations in the study.

Conclusions

Modified anterior bilayered ceramic restorations showed good survival rates, and no chipping was observed up to 6 years of follow-up. Parafunctional habits and endodontic treatment had a negative effect on the survival rate of restorations. The support of tooth or implant and the restoration type had no effect on the survival.

中文翻译：

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使用二硅酸锂加固切缘的双层陶瓷前牙修复体：最多 6 年随访的多中心回顾性生存分析

问题陈述

如果在颊侧铺上长石陶瓷，可以提高前牙二硅酸锂修复体的美观度。然而，这一层的骨折和碎裂是否是一种普遍的并发症尚不清楚。

目的

本回顾性研究的目的是评估在牙齿和种植体上进行间接前牙双层修复的特殊设计的切缘二硅酸锂增强材料的切缘断裂发生率。

材料与方法

4 名修复牙医在一个牙科实验室制作了 324 名患者的 924 个前牙双层压制二硅酸锂修复体。修复体具有整体二硅酸锂切缘的腭侧和长石瓷的面部侧。评估修复体的存活率和断裂或碎裂的发生率。使用 Kaplan-Meier 和对数秩 (Mantel-Cox) 检验 (α=.05) 进行生存分析。

结果

在 924 个修复体中，798 个（236 个全冠，562 个部分修复体）放置在牙齿上，126 个放置在种植体上。平均观察时间为 38 个月（3 至 72 个月）。存活率为96.5%，失败14次。失败是牙外伤后骨折（n=5）、陶瓷断裂（n=1）、脱粘（n=6）、颜色匹配不良（n=1）和牙齿脱落（n=2）。具有功能异常习惯和牙髓治疗牙齿的患者的修复显示存活率显着降低 ( P =.018)。牙齿和种植体修复体的存活率之间以及全冠和部分修复体之间没有发现显着差异 ( P =.021)。在研究中的任何修复体上均未观察到碎裂。

结论

改良的前牙双层陶瓷修复体显示出良好的存活率，并且在长达 6 年的随访中没有观察到碎裂。功能异常习惯和牙髓治疗对修复体的存活率有负面影响。牙齿或种植体的支持和修复类型对生存没有影响。