Statement of problem

Implant-supported fixed dental prostheses have been classified into screw-retained and cement-retained types, and each retaining type has complications. A novel retentive cementless double crown (CLD) type of the implant-supported fixed prosthesis has been developed. CLD has air pockets in the intaglio surface of the crown and does not require cement or a screw hole. However, studies on the retention force and stress distribution of the system are lacking.

Purpose

The purpose of this in vitro study was to evaluate the retention force and stress distribution in the CLD system.

Material and methods

The specimen comprised an implant, a titanium abutment, and a zirconia crown. Retention forces of 10 specimens of the CLD type were measured at no loading and after cyclic loading for 50, 100, 200, 600, 10 000, and 1 000 000 cycles by using a universal testing machine with a custom attachment device. Forty specimens of the stress distribution test were divided into 4 groups based on the retention type (cement-retained or CLD type) and load direction (vertical or oblique). Strain gauges were attached onto the buccal and lingual sides of the implant, and microstrain values were measured. One-way analysis of variance with the post hoc Tukey honestly significant difference test was performed on the retention force data, and the t test was performed to analyze the microstrain value data (α=.05).

Results

Retention forces after 0, 50, 100, 200, 600, 10 000, and 1 000 000 load cycles were 18.12 ±6.16 N, 20.47 ±5.78 N, 19.79 ±6.61 N, 18.46 ±5.23 N, 19.60 ±6.93 N, 21.75 ±5.03 N, and 40.91 ±9.32 N, respectively, and after 1 000 000 cycles, the retention force was significantly higher than that of other load cycles (P<.05). The mean of maximum microstrain values under the vertical load were similar in the cement-retained type (buccal side, 834.96 ±53.69 μm/m; lingual side, 490.76 ±34.12 μm/m) and the CLD type (buccal side, 814.28 ±71.20 μm/m; lingual side, 479.10 ±30.74) (P>.05), and the mean of maximum microstrain values under the oblique load was also similar in the cement-retained type (buccal side, 1991.04 ±109.89 μm/m; lingual side, -2232.41 ±189.88) and the CLD type (buccal side, 1932.47 ±152.51 μm/m; lingual side, -2097.47 ±130.69 μm/m) (P>.05).

Conclusions

The CLD type had clinically acceptable retention during 1 000 000 load cycles and had a similar or better stress distribution capability than the cement-retained type.

中文翻译：

---

非骨水泥双冠型种植体支持修复体的固位力及应力分布分析

问题陈述

种植体支持的固定义齿分为螺钉固位型和水泥固位型，每种固位型都有并发症。已开发出一种新型固位性非骨水泥双冠 (CLD) 型种植体支持的固定修复体。CLD 在表冠的凹版表面有气穴，不需要胶合剂或螺丝孔。然而，缺乏对系统的保持力和应力分布的研究。

目的

这项体外研究的目的是评估 CLD 系统中的保持力和应力分布。

材料与方法

该样本包括一个种植体、一个钛基台和一个氧化锆牙冠。使用带有定制附件装置的通用试验机，在空载和循环加载 50、100、200、600、10000 和 1000000 次循环后测量了 10 个 CLD 类型试样的保持力。40 个应力分布试验试件根据固位类型（水泥固位或 CLD 型）和载荷方向（垂直或倾斜）分为 4 组。应变计安装在种植体的颊侧和舌侧，并测量微应变值。对保持力数据进行单因素方差分析和事后Tukey诚实显着性差异检验，对微应变值数据进行t检验（α=.05）。

结果

0、50、100、200、600、10 000 和 1 000 000 次负载循环后的保持力分别为 18.12 ±6.16 N、20.47 ±5.78 N、19.79 ±6.61 N、18.46 ±5.23 N、19.60 ±6.93 N、21.75 ±分别为 5.03 N 和 40.91 ±9.32 N，在 1 000 000 次循环后，保持力显着高于其他负载循环（P <.05）。垂直载荷下最大微应变值的平均值在骨水泥保留型（颊侧，834.96 ±53.69 μm/m；舌侧，490.76 ±34.12 μm/m）和 CLD 型（颊侧，814.28 ±71.20 μm/m；舌侧，479.10 ±30.74) ( P>.05），并且在倾斜载荷下的最大微应变值的平均值在骨水泥保留型（颊侧，1991.04 ±109.89 μm/m；舌侧，-2232.41 ±189.88）和 CLD 型（颊侧）中也相似。侧，1932.47 ±152.51 μm/m；舌侧，-2097.47 ±130.69 μm/m) ( P >.05)。

结论

CLD 型在 1 000 000 次负载循环期间具有临床可接受的保持力，并且具有与水泥保持型相似或更好的应力分布能力。