前磨牙邻面板固位全瓷粘接桥修复的应用研究

目的 探究IPS e.max Press玻璃基铸造陶瓷和WIELAND氧化锆陶瓷邻面板固位粘接桥修复下颌第二前磨牙缺失的抗折性能及模拟短期使用后的修复效果。方法 选取成人离体下颌第一前磨牙和第一磨牙各32颗,体外建立下颌第二前磨牙缺失模型。随机分为4组（n=8）,E0组:IPS e.max Press铸瓷粘接桥;E1组:IPS e.max Press铸瓷粘接桥+30万次机械循环加载;W0组:WIELAND氧化锆全瓷粘接桥;W1组:WIELAND氧化锆全瓷粘接桥+30万次机械循环加载。万能测试机测试各实验组的破坏载荷力值。结果 机械循环加载后试件均无松动或脱落,无明显裂纹。万能测试机测试结果:E0、E1、W0、W1组破坏载荷分别为（1 242.85±260.11）、（1 062.60±179.98）、（1 650.85±206.77）、（1 167.61±265.50） N,均大于下颌第二前磨牙所受最大力（360 N）,差异有统计学意义（P<0.001）。E0组破坏载荷小于W0组（P<0.05）。循环加载后,E1组和W1组间差异无统计学意义（P>0.05）。循环加载后,铸瓷组（E1、E0）破坏载荷变化不显著（P>0.05）,氧化锆组（W0、W1）明显降低（P<0.05）。结论 IPS e.max Press铸瓷和WIELAND氧化锆全瓷邻面板固位粘接桥修复下颌第二前磨牙缺失均能够获得良好的抗折性能,短期修复效果满意。

All-ceramic premolar guiding plate retains resin-bonded fixed partial dentures

Objective This study aims to investigate the fracture resistance and short-term restorative effects of resin-bonded fixed partial dentures (RBFPDs) made from heat-pressed lithium-disilicate-based glass-ceramic (IPS e.max press) and zirconia ceramic (WIELAND) and retained by all-ceramic guiding plates when used to restore missing mandibular second premolars. Methods A total of 64 human mandibular first premolars and first molars were prepared as abutments, then were randomly divided into 4 groups (n=8): E0, heat-pressed ceramic RBFPDs, no cyclic loading; E1, heat-pressed ceramic RBFPDs exposed to 300 000 cycles of dynamic loading; W0, zirconia ceramic RBFPDs, no cyclic loading; and W1, zirconia ceramic RBFPDs exposed to 300 000 cycles of dynamic loading. Fracture strength was tested in a universal testing machine. Results The medians of fracture strength were 1 242.85 N±260.11 N (E0), 1 650.85 N±206.77 N (W0), 1 062.60 N±179.98 N (E1), and 1 167.61 N±265.50 N (W1). Statistical analysis showed that all the groups exhibited significantly higher fracture strength compared with the maximum bite force in the premolar region (360 N; P<0.001). The W0 group had significantly higher fracture strength than the E0 group (P<0.05). Meanwhile, no significant difference in fracture strength was observed between the E1 and W1 groups (P>0.05). Significant statistical differences were found between the zirconia ceramic groups (W0 and W1, P<0.05) but not between the glassceramic groups (E0 and E1, P>0.05) after dynamic loading. Conclusion- The RBFPDs retained by all-ceramic guiding plates exhibited promising fracture properties and optimal short-term restorative effects when used to restore missing mandibular second premolars.