Abstract：
OBJECTIVE: Severe anterior maxillary atrophy offers few implant-supported rehabilitation solutions to Quad Zygoma characterized by a wide anterior cantilever. One of the possible alternatives to consider before the quad zygoma is the extra-long nasal/trans-nasal implant placement. This retrospective multicentric study shows the predictability of nasal/transnasal implant placement in patients affected by severe anterior maxilla atrophy, with residual anatomical features that indicate this surgery. This specific remote anchorage can often be safely involved in immediate loading with other remote anchorages, such as zygoma and pterygoid implants. In this rehabilitation, it\'s mandatory to reduce the instability of the frameworks and mechanical stress that could unfavorably affect the implant\'s prognosis due to the overloading derived from anterior bending.
METHODS: In this retrospective multicentric study, 52 nasal or trans-nasal implants were inserted in 31 atrophic anterior maxillas (Cawood and Howell\'s class V-VI). All implants were successful after the healing period; even if 27 nasal implants reached an insertional torque equal to or greater than 50 n/cm2, the threshold value estimated to be able to support an immediate load.
RESULTS: All 52 implants were successful, so the proportion of success was 100%, with a 97.5% one-sided confidence interval of 88.8-100%. The success rate is achieved only if at least two of the following criteria are met: 1) a greater torque than 50 Ncm as a minimum sufficient condition to plan immediate loading; 2) after a healing period of 16 weeks, the secondary stability is clinically and radiographically evaluated to exclude possible coronal bone resorption: this condition allows the successive prosthetic finalization; 3) the possibility of carrying out a full arch rehabilitation with minimal anterior spread. Insertion torque was <50 Newton centimeters (Ncm) in 14 patients (45%) and 50 Ncm in 17 (55%). Mechanical load was delayed in the former and immediate in the latter. The proportion of torque <50 Ncm was higher in men than in women (69% versus 28%, p=0.033). Immediate torque was not significantly affected by age.
CONCLUSIONS: Although the sample is not extremely numerically significant, it conveys a clear and significant clinical, surgical indication as never before in the literature; we can state that nasal/trans nasal implants have been very useful in reducing the anterior cantilever and overcoming the anatomical limitations affecting conventional Quad Zygoma.
METHODS: In this retrospective multicentric study, 52 nasal or trans-nasal implants were inserted in 31 atrophic anterior maxillas (Cawood and Howell\'s class V-VI). All implants were successful after the healing period; even if 27 nasal implants reached an insertional torque equal to or greater than 50 n/cm2, the threshold value estimated to be able to support an immediate load.
RESULTS: All 52 implants were successful, so the proportion of success was 100%, with a 97.5% one-sided confidence interval of 88.8-100%. The success rate is achieved only if at least two of the following criteria are met: 1) a greater torque than 50 Ncm as a minimum sufficient condition to plan immediate loading; 2) after a healing period of 16 weeks, the secondary stability is clinically and radiographically evaluated to exclude possible coronal bone resorption: this condition allows the successive prosthetic finalization; 3) the possibility of carrying out a full arch rehabilitation with minimal anterior spread. Insertion torque was <50 Newton centimeters (Ncm) in 14 patients (45%) and 50 Ncm in 17 (55%). Mechanical load was delayed in the former and immediate in the latter. The proportion of torque <50 Ncm was higher in men than in women (69% versus 28%, p=0.033). Immediate torque was not significantly affected by age.
CONCLUSIONS: Although the sample is not extremely numerically significant, it conveys a clear and significant clinical, surgical indication as never before in the literature; we can state that nasal/trans nasal implants have been very useful in reducing the anterior cantilever and overcoming the anatomical limitations affecting conventional Quad Zygoma.
摘要：
目的：严重的上颌前萎缩对以宽的前悬臂为特征的四头肌提供了很少的植入物支持的康复解决方案。在四头zygoma之前要考虑的可能替代方案之一是超长的鼻/经鼻植入物放置。这项回顾性多中心研究显示了严重上颌骨前萎缩患者鼻/经鼻植入物放置的可预测性，残余的解剖特征表明这种手术。该特定的远程锚具通常可以安全地与其他远程锚具一起立即装载。如zygoma和翼状体植入物。在这种康复中，这是强制性的，以减少不稳定的框架和机械应力，可能不利地影响植入物的预后，由于过载的前弯曲。
方法：在这项回顾性多中心研究中，在31个萎缩的前上颌骨（Cawood和Howell的V-VI级）中插入了52个鼻或经鼻植入物。所有植入物在愈合期后均成功；即使27个鼻植入物达到等于或大于50n/cm2的插入扭矩，该阈值估计也能够支持即时负载。
结果：所有52个植入物均成功，所以成功的比例是100%，97.5%的单边置信区间为88.8-100%。只有满足以下标准中的至少两个，才能达到成功率：1）大于50Ncm的扭矩作为计划立即加载的最小充分条件；2）在16周的愈合期后，在临床和影像学上评估次要稳定性，以排除可能的冠状骨吸收：这种情况允许连续的假体完成；3）以最小的前路扩散进行完整的足弓康复的可能性。14例患者（45％）的插入扭矩<50牛顿厘米（Ncm），17例患者（55％）的插入扭矩<50牛顿厘米。机械载荷在前者中延迟，而在后者中立即延迟。男性扭矩<50Ncm的比例高于女性(69%对28%,p=0.033)。即时扭矩不受年龄的显著影响。
结论：虽然样本在数值上并不显著，它传达了一个清晰而有意义的临床，手术适应症是文献中从未有过的；我们可以说，鼻/经鼻植入物在减少前悬臂和克服影响传统四足关节的解剖学限制方面非常有用。
方法：在这项回顾性多中心研究中，在31个萎缩的前上颌骨（Cawood和Howell的V-VI级）中插入了52个鼻或经鼻植入物。所有植入物在愈合期后均成功；即使27个鼻植入物达到等于或大于50n/cm2的插入扭矩，该阈值估计也能够支持即时负载。
结果：所有52个植入物均成功，所以成功的比例是100%，97.5%的单边置信区间为88.8-100%。只有满足以下标准中的至少两个，才能达到成功率：1）大于50Ncm的扭矩作为计划立即加载的最小充分条件；2）在16周的愈合期后，在临床和影像学上评估次要稳定性，以排除可能的冠状骨吸收：这种情况允许连续的假体完成；3）以最小的前路扩散进行完整的足弓康复的可能性。14例患者（45％）的插入扭矩<50牛顿厘米（Ncm），17例患者（55％）的插入扭矩<50牛顿厘米。机械载荷在前者中延迟，而在后者中立即延迟。男性扭矩<50Ncm的比例高于女性(69%对28%,p=0.033)。即时扭矩不受年龄的显著影响。
结论：虽然样本在数值上并不显著，它传达了一个清晰而有意义的临床，手术适应症是文献中从未有过的；我们可以说，鼻/经鼻植入物在减少前悬臂和克服影响传统四足关节的解剖学限制方面非常有用。
