Bressan Eriberto, Grusovin Maria Gabriella, D'Avenia Ferdinando, Neumann Konrad, Sbricoli Luca, Luongo Giuseppe, Esposito Marco
Eur J Oral Implantol. 2017;10(4):373-390.
To evaluate the influence of at least three abutment disconnections in conventional loaded implants against placement of a definitive abutment in immediately non-occlusal loaded implants on hard and soft tissue changes. A secondary aim was to evaluate whether the presence of less than 2 mm of keratinised mucosa is associated with increased peri-implant marginal bone loss and soft tissue recessions.
Eighty patients requiring one single crown or one fixed partial prosthesis supported by a maximum of three implants were randomised, after implants were placed with more than 35 Ncm, according to a parallel group design to receive definitive abutments that were loaded immediately (definitive abutment or immediate loading group) or transmucosal abutments, which were delayed loaded after 3 months and removed at least three times: 1. At impression taking (3 months after implant placement); 2. When checking the zirconium core on titanium abutments at single crowns or the fitting the metal structure at prostheses supported by multiple implants; 3. At delivery of the definitive prostheses (repeated disconnection or conventional loading group). Patients were treated at four centres and each patient contributed to the study, with only one prosthesis followed for 3 years after initial loading. Outcome measures were: prosthesis failures, implant failures, complications, pink aesthetic score (PES), buccal recessions, patient satisfaction, peri-implant marginal bone level changes and height of the keratinised mucosa.
Forty patients were randomly allocated to each group according to a parallel group design. Six patients from the definitive abutment group dropped out or died, and one left from the repeated disconnection group. One implant, from the repeated disconnection group, fractured (difference = 3%; CI 95%: -2%, 8%; P = 1). Four provisional crowns and one definitive single crown had to be remade because of poor fitting, and one definitive crown and one definitive prosthesis because of ceramic and implant fracture, respectively, in the repeated disconnection group vs one provisional prosthesis from the definitive abutment group due to frequent debondings (difference = 15%; CI 95%: 2%, 28%; P = 0.060). Five patients from the definitive abutment group and four patients from the repeated disconnection group were affected by complications (difference = 4%; CI 95%: -11%, 20%; P = 0.725). PES scores assessed at 3 years post-loading were 11.7 (standard deviation = 1.8) mm for the definitive abutment group and 11.3 (1.5) mm for the repeated abutment changes group (difference = 0.4; CI 95%: -0.4, 1.2; P = 0.315). However, there was a difference of 0.26 out of a maximum score of 2 in favour of the definitive abutment group for soft tissue contour only. Buccal recessions at 3 years post-loading amounted to -0.1 (0.8) mm for the definitive abutment group and -0.1 (1.2) mm for the repeated abutment changes group (it was actually a soft tissue gain; difference = 0.01 mm CI 95%: -0.48, 0.50; P = 0.965). All patients declared being very satisfied or satisfied with the function and aesthetics of the prostheses and said they would undergo the same procedure again, with the exception of one patient from the repeated disconnection group who was uncertain regarding function. Mean peri-implant marginal bone loss 3 years after loading was 0.07 (0.18) mm for the definitive abutment group and 0.50 (0.93) mm for the repeated abutment changes group (difference = 0.43 mm; CI 95%: 0.13, 0.74; P = 0.007). The height of keratinised mucosa at 3 years post-loading was 2.8 (1.3) mm for the definitive abutment group and 2.8 (1.6) mm for the repeated abutment changes group (difference = 0.03; CI 95%: -0.67, 0.73; P = .926). Up to 3 years after initial loading there were no statistically significant differences between the two procedures, with the exception of 0.4 mm more marginal bone loss at implants subjected to three abutment disconnections. There were no significantly increased marginal bone loss (difference = 0.1 mm, CI 95%: -0.3, 0.5, P = 0.590) or buccal recessions (difference = 0.1 mm, CI 95%: -0.4, 0.7, P = 0.674) at implants with less than 2 mm of keratinised mucosa at loading.
Three-year post-loading data showed that repeated abutment disconnections significantly increased bone loss of 0.43 mm, but this difference may not be considered clinically relevant; therefore clinicians can use the procedure they find more convenient for each specific patient. Immediately non-occlusally loaded dental implants are a viable alternative to conventional loading and no increased bone loss or buccal recessions were noticed at implants with less than 2 mm of keratinised mucosa. Conflict of interest statement: This trial was partially funded by Dentsply Sirona Implants, the manufacturer of the implants and other products evaluated in this investigation. However, data belonged to the authors and by no means did the manufacturer interfere with the conduct of the trial or the publication of the results, with the exception of rejecting a proposal to change the protocol, after the trial was started, allowing the use of indexed abutments.
评估在常规负载种植体中至少三次基台连接断开对即刻非咬合负载种植体上最终基台放置时软硬组织变化的影响。次要目的是评估角化黏膜小于2 mm是否与种植体周围边缘骨丢失增加和软组织退缩有关。
80例需要单冠或最多由三颗种植体支持的固定局部义齿的患者，在种植体以超过35 Ncm的扭矩植入后，根据平行组设计随机分组，接受即刻负载最终基台（最终基台或即刻负载组）或穿黏膜基台，后者在3个月后延迟负载并至少拆卸三次：1. 取印模时（种植体植入后3个月）；2. 在单冠检查钛基台上的锆核或在多颗种植体支持的修复体上安装金属结构时；3. 最终修复体交付时（重复断开连接或常规负载组）。患者在四个中心接受治疗，每位患者参与本研究，仅对一个修复体在初始负载后随访3年。观察指标包括：修复体失败、种植体失败、并发症、粉色美学评分（PES）、颊侧退缩、患者满意度、种植体周围边缘骨水平变化和角化黏膜高度。
根据平行组设计，每组随机分配了40例患者。最终基台组有6例患者退出或死亡，重复断开连接组有1例退出。重复断开连接组有1颗种植体发生骨折（差异 = 3%；95%置信区间：-2%，8%；P = 1）。重复断开连接组有4个临时冠和1个最终单冠因贴合不良需要重新制作，1个最终冠和1个最终修复体分别因陶瓷和种植体骨折需要重新制作，而最终基台组有1个临时修复体因频繁脱粘需要重新制作（差异 = 15%；95%置信区间：2%，28%；P = 0.060）。最终基台组有5例患者和重复断开连接组有4例患者出现并发症（差异 = 4%；95%置信区间：-11%，20%；P = 0.725）。负载后3年评估的PES评分，最终基台组为11.7（标准差 = 1.8）mm，重复基台变化组为11.3（1.5）mm（差异 = 0.4；95%置信区间：-0.4，1.2；P = 0.315）。然而，仅在软组织轮廓方面，最终基台组在满分2分中比重复基台变化组高出0.26分。负载后3年的颊侧退缩，最终基台组为-0.1（0.8）mm，重复基台变化组为-0.1（1.2）mm（实际上是软组织增加；差异 = 0.01 mm，95%置信区间：-0.48，0.50；P = 0.965）。所有患者均表示对修复体的功能和美观非常满意或满意，并表示愿意再次接受相同的治疗，但重复断开连接组有1例患者对功能不确定。负载后3年，最终基台组种植体周围平均边缘骨丢失为0.07（0.18）mm，重复基台变化组为0.50（0.93）mm（差异 = 0.43 mm；95%置信区间：0.13，0.74；P = 0.007）。负载后3年，最终基台组角化黏膜高度为2.8（1.3）mm，重复基台变化组为2.8（1.6）mm（差异 = 0.03；95%置信区间：-0.67，0.73；P = 0.926）。初始负载后长达3年，两种方法之间除了经历三次基台连接断开的种植体边缘骨丢失多0.4 mm外，无统计学显著差异。在负载时角化黏膜小于2 mm的种植体中，边缘骨丢失（差异 = 0.1 mm，95%置信区间：-0.3，0.5，P = 0.590）或颊侧退缩（差异 = 0.1 mm，95%置信区间：-0.4，0.7，P = 0.674）均未显著增加。
负载后3年的数据表明，重复基台连接断开显著增加了0.
