PurposeInvestigate survival and technical complications of two‐unit posterior implant‐supported cantilever made of monolithic zirconia on titanium‐base abutments (Zr‐TiB) vs. porcelain‐fused‐to‐metal on castable gold abutments (PFM‐GA) using two different implant connections, internal butt‐joint (IBJ) and internal conical (IC).Materials and MethodsForty‐eight implants (4.3 mm diameter) were divided into four groups (n = 12) to support 2‐unit mandibular premolar cantilevers with two different materials (Zr‐TiB vs. PFM‐GA) and two connection types (IBJ vs. IC). Tested groups were as follows: (1) IBJ/Zr‐TiB; (2) IBJ/PFM‐GA; (3) IC/Zr‐TiB; and (4) IC/PFM‐GA. Specimens were thermomechanical aged (1,200,000 cycles, 98 N, 5–55°C) with occlusal axial load on the pontic. Catastrophic and non‐catastrophic events were registered, and removal torque values measured before and after aging. Specimens surviving aging were subjected to loading until failure. Survival, total complication rates, torque loss (%), and bending moments were calculated.ResultsFrom 48 specimens, 38 survived aging. Survival rates significantly varied from 16.7% (IC/PFM‐GA) to 100% (IBJ/Zr‐TiB; IBJ/PFM‐GA; IC/Zr‐TiB) (p < .01). Internal conical connection revealed significantly higher torque loss (IC/ZrTiB – 67%) compared to internal butt‐joint (IBJ/Zr‐TiB – 44%; IBJ/PFM‐GA – 46%) (p < .01). Bending moments were higher in internal butt‐joint connections than in internal conical (p < .05).Conclusion and Clinical ImplicationsTwo‐unit posterior implant‐supported cantilever FDPs replacing mandibular premolars composed of monolithic zirconia on titanium‐base abutments demonstrated higher mechanical stability compared to porcelain‐fused‐to‐metal on castable gold abutments in this in vitro study. The internal conical connection combined with porcelain‐fused‐to‐metal on gold abutments revealed a high number of failures; therefore, their clinical use may be considered cautiously for this indication.

中文翻译：

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钛基基台上后牙种植体支撑的整体氧化锆悬臂的机械稳定性。体外研究

目的使用两种不同的种植体，研究钛基基台 (Zr-TiB) 上的整体氧化锆制成的双单元后牙种植体支撑悬臂与可铸金基台 (PFM-GA) 上的烤瓷熔附金属悬臂 (PFM-GA) 的生存率和技术并发症连接、内部对接 (IBJ) 和内部圆锥 (IC)。 材料和方法 48 个种植体（直径 4.3 毫米）分为四组（n= 12）支持具有两种不同材料（Zr-TiB 与 PFM-GA）和两种连接类型（IBJ 与 IC）的 2 单元下颌前磨牙悬臂。测试组如下：（1）IBJ/Zr-TiB；(2) IBJ/PFM-GA；（3）IC/Zr-TiB；(4) IC/PFM-GA。样本经过热机械老化（1,200,000 次循环，98 N，5–55°C），并在桥体上施加咬合轴向载荷。记录灾难性和非灾难性事件，并测量老化前后的移除扭矩值。经受住老化考验的样品承受载荷直至失效。计算存活率、总并发症率、扭矩损失 (%) 和弯矩。结果 48 个样本中，38 个在老化后幸存。存活率显着变化，从 16.7%（IC/PFM-GA）到 100%（IBJ/Zr-TiB；IBJ/PFM-GA；IC/Zr-TiB）（p< .01)。与内部对接接头（IBJ/Zr-TiB – 44%；IBJ/PFM-GA – 46%）相比，内部锥形连接的扭矩损失（IC/ZrTiB – 67%）明显更高（p< .01)。内部对接连接的弯矩高于内部锥形连接（p< .05). 结论和临床意义在体外试验中，与可铸金基台上的烤瓷熔附金属相比，钛基基台上由整体氧化锆组成的双单元后牙种植体支撑悬臂 FDP 取代了下颌前磨牙，表现出更高的机械稳定性学习。内部圆锥形连接与金基台上的瓷熔合金属相结合显示出大量的失败；因此，对于该适应症，临床使用应谨慎考虑。