Department of Clinical Sciences and Translational Medicine, School of Dentistry, University of Rome Tor Vergata, Rome, Italy.
Department of Dentistry, San Raffaele Scientific Institute, Vita Salute University, Milan, Italy.
J Prosthodont. 2017 Jul;26(5):387-394. doi: 10.1111/jopr.12406. Epub 2015 Nov 30.
The purpose of this retrospective investigation was to evaluate the use of a prefabricated bar system for immediately loaded implants placed and restored according to the All-on-Four concept with up to 24-month follow-up.
A total of 51 patients (31 males and 20 females; mean age 63.4 years) presented with edentulous or partially edentulous jaws with severe atrophy of the posterior regions. All patients were treated with full-arch fixed prostheses (28 maxillary, 34 mandibular) each supported by four implants (two vertical, two distally tilted). The implants were immediately loaded with screw-retained full-arch restorations. Each prosthesis was supported by a prefabricated metal bar combined with high-density acrylic resin. Follow-up visits were scheduled at 6, 12, and 24 months after initial prosthetic loading. Intraoral radiographs were obtained immediately after surgery and at each follow-up visit by using a custom radiograph holder and parallel technique. Marginal bone levels were assessed using digital image analysis. Implant and prosthetic survival and success rates were evaluated. Patient satisfaction was further assessed using a 100-mm visual analog scale (VAS). Data were compared by means of the Mantel-Haenszel test.
No drop-outs occurred. The overall implant survival rates were 100% and 98.38% for the vertical and tilted implants respectively. Two of the 62 definitive fixed prostheses were lost during the observation period due to implant failure. Since restoration replacement due to implant failure was not judged a prosthodontic failure according to the survival criteria provided in this study, the overall prosthetic survival rate was 100%. No statistically significant differences in marginal bone levels between vertical and tilted implants were detected at 24-month follow-up evaluation in either jaw. All participants were functionally and esthetically satisfied with their definitive restorations after 2 years functioning, as confirmed by the average VAS scores (masticatory function: 99.7; phonetic function: 99.5, esthetics: 99.2).
The preliminary 24-month results indicate that immediate loading of vertical and tilted implants using the evaluated prefabricated bar system may be a viable solution for edentulous jaw rehabilitation; however, more long-term prospective clinical trials are needed to affirm the effectiveness of this surgical-prosthetic protocol.
本回顾性研究的目的是评估使用预制杆系统对按照 All-on-Four 概念植入并即刻负载的种植体进行 24 个月随访的效果。
共有 51 名患者（31 名男性，20 名女性；平均年龄 63.4 岁），牙槽骨完全或部分缺失，后牙区严重萎缩。所有患者均采用全口固定义齿修复（28 例上颌，34 例下颌），每个义齿由 4 个种植体（2 个垂直，2 个远中倾斜）支撑。种植体即刻采用螺丝固位的全口修复体负载。每个义齿均由预制金属杆与高密度丙烯酸树脂结合支撑。初始修复体负载后 6、12 和 24 个月进行随访。术后即刻以及每次随访时均使用定制的射线照相固定器和平行技术获取口内射线照片。使用数字图像分析评估边缘骨水平。评估种植体和修复体的存活率和成功率。进一步使用 100mm 视觉模拟量表（VAS）评估患者满意度。采用 Mantel-Haenszel 检验比较数据。
无脱落病例。垂直种植体和倾斜种植体的总体种植体存活率分别为 100%和 98.38%。在观察期间，由于种植体失败，有 2 个 62 个最终固定义齿丢失。由于根据本研究中提供的生存标准，由于种植体失败而进行修复体更换不被视为修复失败，因此总体修复体存活率为 100%。在 24 个月随访评估中，无论在哪个颌骨，垂直种植体和倾斜种植体的边缘骨水平均无统计学差异。所有患者在经过 2 年的功能使用后，对最终修复体的功能和美观均非常满意，这一点得到了平均 VAS 评分（咀嚼功能：99.7；语音功能：99.5，美观：99.2）的证实。
初步 24 个月结果表明，使用评估的预制杆系统即刻负载垂直和倾斜种植体可能是无牙颌修复的可行解决方案；然而，需要更多的长期前瞻性临床试验来证实该手术-修复方案的有效性。
