Abstract：
OBJECTIVE: Investigate 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).
METHODS: Forty-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.
RESULTS: From 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).
CONCLUSIONS: Two-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.
METHODS: Forty-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.
RESULTS: From 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).
CONCLUSIONS: Two-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.
摘要：
目的：研究钛基基台（Zr-TiB）上由整体式氧化锆制成的两单元后部植入物支撑悬臂的存活率和技术并发症使用两种不同的植入物连接在可铸造金基台（PFM-GA）上的瓷融合金属，内部对接接头（IBJ）和内部圆锥形（IC）。
方法：将48个植入物（直径4.3mm）分为四组（n=12），以两种不同的材料（Zr-TiBvs.PFM-GA)和两种连接类型(IBJ与IC）。试验组如下:(1)IBJ/Zr-TiB;(2)IBJ/PFM-GA;(3)IC/Zr-TiB;和(4)IC/PFM-GA。样品进行了热机械老化(1,200,000次循环，98N,5-55°C），在桥体上施加咬合轴向载荷。记录了灾难性和非灾难性事件，以及老化前后测量的去除扭矩值。对老化存活的样品进行加载直至失效。生存,总并发症发生率,扭矩损失(%),并计算了弯矩。
结果：来自48个样本，38岁幸存下来。存活率从16.7%(IC/PFM-GA)到100%(IBJ/Zr-TiB;IBJ/PFM-GA;IC/Zr-TiB)显著变化(p<.01)。与内部对接接头(IBJ/Zr-TiB-44%;IBJ/PFM-GA-46%)相比,内部锥形连接显示出显著更高的扭矩损失(IC/ZrTiB-67%)(p<.01)。内部对接连接的弯矩高于内部圆锥形连接的弯矩（p<.05）。
结论：在这项体外研究中，两单元后种植体支撑悬臂FDP替代了钛基基基上由整体氧化锆组成的下颌前磨牙，与可铸造金基上的瓷熔接金属相比，具有更高的机械稳定性。内部圆锥形连接与金基台上的瓷熔金属结合显示出大量故障；因此，对于该适应症，可以谨慎考虑其临床使用。
方法：将48个植入物（直径4.3mm）分为四组（n=12），以两种不同的材料（Zr-TiBvs.PFM-GA)和两种连接类型(IBJ与IC）。试验组如下:(1)IBJ/Zr-TiB;(2)IBJ/PFM-GA;(3)IC/Zr-TiB;和(4)IC/PFM-GA。样品进行了热机械老化(1,200,000次循环，98N,5-55°C），在桥体上施加咬合轴向载荷。记录了灾难性和非灾难性事件，以及老化前后测量的去除扭矩值。对老化存活的样品进行加载直至失效。生存,总并发症发生率,扭矩损失(%),并计算了弯矩。
结果：来自48个样本，38岁幸存下来。存活率从16.7%(IC/PFM-GA)到100%(IBJ/Zr-TiB;IBJ/PFM-GA;IC/Zr-TiB)显著变化(p<.01)。与内部对接接头(IBJ/Zr-TiB-44%;IBJ/PFM-GA-46%)相比,内部锥形连接显示出显著更高的扭矩损失(IC/ZrTiB-67%)(p<.01)。内部对接连接的弯矩高于内部圆锥形连接的弯矩（p<.05）。
结论：在这项体外研究中，两单元后种植体支撑悬臂FDP替代了钛基基基上由整体氧化锆组成的下颌前磨牙，与可铸造金基上的瓷熔接金属相比，具有更高的机械稳定性。内部圆锥形连接与金基台上的瓷熔金属结合显示出大量故障；因此，对于该适应症，可以谨慎考虑其临床使用。
