Statement of problem

Endocrowns have been reported to be successful restorations for endodontically treated molars. However, comparisons between maxillary and mandibular molars, with different pulp chamber configurations are lacking. Information on the influence of venting on the adaptation of endocrowns is also lacking.

Purpose

The purpose of this in vitro study was to evaluate the adaptation of endocrowns in maxillary and mandibular molars by means of microcomputed tomography (μCT).

Material and methods

Mandibular and maxillary first molars were divided into 4 groups (n=10): ManE: mandibular endocrown; ModManE: modified mandibular endocrown; MaxE: maxillary endocrown; and ModMaxE: modified maxillary endocrown. Endocrowns were produced by using computer-aided design and computer-aided manufacture (CAD-CAM). Modification was carried out on the part of the endocrown that extended into the pulp chamber by preparing vents. The specimens were cemented and scanned by using μCT, the images reconstructed, and the internal and marginal adaptation examined. Statistical analyses were performed by using a 3-way ANOVA, 2-way ANOVA, and the independent samples t test (α=.05).

Results

ManE displayed better mean ±standard deviation internal adaptation (182 ±59 μm) than MaxE (215 ±55 μm) (P<.01). Regardless of the groups, the pulpal floor was the area with the poorest fit (P<.001). The marginal gap of mandibular molars (91 ±20 μm) was lower than that of maxillary molars (110 ±26 μm) (P<.05). The effect of modifying endocrowns on the marginal gap was not found to be statistically significant (P>.05).

Conclusions

Internal and marginal adaptation of endocrowns differ between maxillary and mandibular molars.

中文翻译：

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检查上颌和下颌磨牙中使用 CAD-CAM 制备的改良内冠的适应性：微计算机断层扫描研究

问题陈述

据报道，Endocrons 可成功修复经牙髓治疗的臼齿。然而，缺乏对具有不同牙髓腔配置的上颌和下颌磨牙的比较。也缺乏关于排气对内分泌适应的影响的信息。

目的

这项体外研究的目的是通过微型计算机断层扫描 (μCT) 评估上颌和下颌磨牙内牙冠的适应性。

材料与方法

下颌和上颌第一磨牙分为 4 组（n=10）：ManE：下颌内冠；ModManE：改良下颌内冠；MaxE：上颌内冠；和 ModMaxE：改良的上颌内冠。Endocrowns 是通过使用计算机辅助设计和计算机辅助制造 (CAD-CAM) 生产的。通过准备通气孔，对延伸到牙髓腔的内冠部分进行了修改。使用μCT对标本进行胶结和扫描，重建图像，并检查内部和边缘适应。通过使用 3-way ANOVA、2-way ANOVA 和独立样本t检验 (α=.05) 进行统计分析。

结果

ManE 显示出比 MaxE (215 ±55 μm) 更好的平均±标准偏差内部适应 (182 ±59 μm) ( P <.01)。无论哪个组，牙髓底都是最差的区域（P <.001）。下颌磨牙的边缘间隙（91±20 μm）低于上颌磨牙的边缘间隙（110 ±26 μm）（P <.05）。未发现修饰内冠对边缘间隙的影响具有统计学意义（P >.05）。

结论

上颌和下颌磨牙的内冠和边缘适应不同。