Int J Oral Implantol (Berl). 2019;12(2):181-194.
To evaluate whether there is a difference in aesthetic outcomes positioning immediate post-extractive implants in the natural position (where the tooth should have been in relation to adjacent teeth/implants) or approximately 3 mm more palatally.
Just after tooth extraction, 20 patients requiring one single immediate maxillary post-extractive implant, from second premolar to second premolar, were randomly allocated to receive either an implant positioned in the natural 'central' position where the tooth should have been (central group; 10 patients) or approximately 3 mm more palatally (palatal group; 10 patients) according to a parallel-group design at two different centres. When needed, sites were reconstructed and bone-to-implant gaps were filled with granules of anorganic bovine bone, covered by resorbable collagen barriers. Implants were left submerged for 4 months and rehabilitated with provisional crowns, replaced after 4 months by metal-ceramic definitive crowns. Patients were followed to 3 years after loading. Outcome measures were: crown and implant failures, complications, aesthetics assessed using the pink aesthetic score (PES), peri-implant marginal bone level changes and patient satisfaction, recorded by blinded assessors.
Three patients from each group dropped out up to 3 years after loading. One implant failed in each group (14%), the difference being not statistically significant (difference in proportion = 0.00; 95% CI: -0.39 to 0.39; P = 1.000). Two palatal group patients and one natural position patient had a complication each, the difference being not statistically significant (difference in proportion = 0.14; 95% CI: -0.28 to 0.52; P = 1.000). Three years after loading, the median PES was 12.5 (interquartile range [IQR] 5.0) for the central and 10.0 (IQR 10.0) for the palatal group, the difference being not statistically significant (median difference = -1.5; 95% CI: -10.0 to 5.0; P = 0.476). Three years after loading, patients of the central group lost 0.25 (IQR 0.40) mm of peri-implant marginal bone and those of the palatal group 0.20 (IQR 0.88) mm, the difference being not statistically significant (median difference = 0.15 mm; P [Mann-Whitney U test] = 0.486). Patients of both groups were equally satisfied at 3 years after loading for both function and aesthetics (both P = 0.699).
These preliminary results suggest that positioning of immediate post-extractive implants 3 mm more palatally may not improve aesthetics; however, the sample size of the present study was very limited, thus larger trials are needed to confirm or reject the present findings. Conflict of interest statement: Mozo-Grau, Valladolid, Spain, the manufacturer of the implants used in this investigation, donated the implants and partially supported this trial; however, data belonged to the authors and by no means did the sponsor interfere with the conduct of the trial or the publication of its results.
评估即刻拔牙后将种植体置于天然位置（即与邻牙/种植体相对应的位置）或略向腭侧 3mm 处，在美学效果方面是否存在差异。
在拔牙后即刻，20 名需要单颗即刻上颌后牙种植体的患者（从第二前磨牙到第二前磨牙），根据平行组设计，在两个不同中心随机分为两组：一组将种植体置于天然的“中央”位置（中央组，10 名患者），另一组略向腭侧（腭侧组，10 名患者）。根据需要，对位点进行重建，用无机牛骨颗粒填充骨-种植体间隙，并用可吸收胶原屏障覆盖。种植体被淹没 4 个月，并用临时冠修复，4 个月后用金属-陶瓷最终冠替代。患者在加载后随访 3 年。主要观察指标：冠和种植体失败、并发症、使用粉红色美学评分（PES）评估的美学效果、种植体周围边缘骨水平变化和患者满意度，由盲法评估者记录。
加载后 3 年内，每组各有 3 名患者脱落。每组各有 1 例种植体失败（14%），差异无统计学意义（比例差异=0.00；95%CI：-0.39 至 0.39；P=1.000）。腭侧组和天然位置组各有 1 例患者出现 1 例并发症，差异无统计学意义（比例差异=0.14；95%CI：-0.28 至 0.52；P=1.000）。加载后 3 年，中央组 PES 的中位数为 12.5（四分位距[IQR]：5.0），腭侧组为 10.0（IQR：10.0），差异无统计学意义（中位数差异=-1.5；95%CI：-10.0 至 5.0；P=0.476）。加载后 3 年，中央组患者的种植体周围边缘骨丧失 0.25（IQR：0.40）mm，腭侧组患者丧失 0.20（IQR：0.88）mm，差异无统计学意义（中位数差异=0.15mm；P[Mann-Whitney U 检验]=0.486）。加载后 3 年，两组患者对功能和美学均同样满意（均 P=0.699）。
这些初步结果表明，将即刻拔牙后种植体向腭侧移动 3mm 可能不会改善美学效果；然而，本研究的样本量非常有限，因此需要更大规模的试验来证实或反驳目前的发现。利益冲突声明：西班牙瓦拉多利德的 Mozo-Grau 公司是本研究中使用的种植体的制造商，该公司捐赠了种植体，并部分支持了本试验；然而，数据属于作者所有，赞助商绝没有干预试验的进行或其结果的发表。
