Clinical Master of Oral Implantology Program, Faculty of Dentistry, Alexandria University, Alexandria, Egypt.
Department of Prosthodontics, Faculty of Dentistry, Alexandria University, 9 Hussein Shereen Street, Louran, Alexandria, Egypt.
BMC Oral Health. 2023 Aug 30;23(1):613. doi: 10.1186/s12903-023-03281-8.
Straight preparable abutments and titanium bases (ti-base) can be used to support single-unit screw-retained lithium disilicate implant-supported restorations. The choice between using both abutments depends on many factors. The purpose of this in vitro study was to compare the masking ability, marginal adaptation, and fracture resistance of screw-retained lithium disilicate implant-supported crowns cemented to straight preparable abutments and ti-bases.
Twenty laboratory implant analogs (Straumann Bone Level; Straumann AG) were randomly divided into 2 groups (n = 10 each) according to the type of the abutment used. Preparable abutment group and ti-base group. Lithium disilicate crowns were used to restore the specimens. All specimens were subjected to thermocycling (from 5 to 55 °C for 2000 cycles) followed by cyclic loading (120 000 cycles). The vertical marginal gap between the abutment finish line and the most apical part of the crown was measured in (µm) by using a stereomicroscope after cementation and after thermocycling and cyclic loading. A spectrophotometer was used to evaluate the masking ability of the specimens after cementation. The load required to fracture the crowns was measured in Newtons (N) by using a universal testing machine after thermocycling and cyclic loading. The Shapiro-Wilk test of normality was used. The appropriate statistical test was used.
Regarding the masking ability, the color difference (∆E) showed no statistically significant difference between the ti-base group (2.6 ± 0.2) and the preparable abutment group (2.6 ± 0.3) (P = .888). The average of the microgap values (µm) was greater in ti-basegroup after cementation (13.9 ± 9.2) than preparable group (7.63 ± 1.78) with no statistically significant difference between the 2 groups (P = .49). After cyclic loading and thermocycling, the average microgap values (µm) was significantly greater in the ti base group (21.3 ± 7.4) than in preparable group (13.3 ± 1.5) (P = .02). The load required to fracture the specimens was greater in the preparable group (1671.5 ± 143.8) than in the ti-base group (1550.2 ± 157.5) with no statistically significant difference between the 2 groups (P = .089).
The abutments used in the present study did not compromise the masking ability of the screw-retained lithium disilicate implant supported crowns. Moreover, the crowns cemented to preparable abutments had better marginal adaptation and higher fracture resistance when compared to those cemented to ti-bases.
Straight preparable abutments are considered as an alternative to the ti-bases when restoring single screw-retained lithium disilicate implant-supported crowns with comparable fracture resistance, marginal adaptation, and masking ability.
直预备基台和钛基底（ti-base）可用于支持单单位螺丝固位的氧化锂硅酸锂种植体支持修复体。选择使用这两种基台取决于许多因素。本体外研究的目的是比较直预备基台和钛基底固位的螺丝固位氧化锂硅酸锂种植体支持修复体的遮色能力、边缘适合性和抗折能力。
将 20 个实验室种植体模拟体（Straumann Bone Level；Straumann AG）随机分为 2 组（每组 10 个），根据使用的基台类型进行分组。预备基台组和 ti-base 组。使用氧化锂硅酸锂冠修复标本。所有标本均进行热循环（5 至 55°C 循环 2000 次），然后进行循环加载（120000 次）。在粘结后、热循环和循环加载后，使用立体显微镜测量基台肩台线和冠最根尖之间的垂直边缘间隙（µm）。粘结后使用分光光度计评估标本的遮色能力。热循环和循环加载后，使用万能试验机测量冠的断裂所需的载荷（牛顿）。使用 Shapiro-Wilk 正态性检验。使用适当的统计检验。
在遮色能力方面，ti-base 组（2.6±0.2）和预备基台组（2.6±0.3）的色差（∆E）无统计学显著差异（P=0.888）。粘结后，ti-base 组的微间隙平均值（µm）（13.9±9.2）大于预备基台组（7.63±1.78），但两组间无统计学显著差异（P=0.49）。经过循环加载和热循环后，ti-base 组的平均微间隙值（µm）（21.3±7.4）明显大于预备基台组（13.3±1.5）（P=0.02）。预备基台组的断裂载荷（1671.5±143.8）大于 ti-base 组（1550.2±157.5），但两组间无统计学显著差异（P=0.089）。
本研究中使用的基台并未影响螺丝固位氧化锂硅酸锂种植体支持修复体的遮色能力。此外，与粘结于 ti-base 的修复体相比，粘结于预备基台的修复体具有更好的边缘适合性和更高的抗折强度。
直预备基台可作为钛基底的替代品，用于修复单颗螺丝固位的氧化锂硅酸锂种植体支持修复体，具有可比拟的抗折强度、边缘适合性和遮色能力。
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