Institute of Odontology, Vilnius University, Vilnius, Lithuania.
Vilnius Research Group, Vilnius, Lithuania.
Clin Implant Dent Relat Res. 2021 Apr;23(2):259-269. doi: 10.1111/cid.12979. Epub 2021 Feb 2.
The relation between implant abutment disconnection (AD) and increased crestal bone loss is still debated.
To compare bone changes below implant-abutment junction of subcrestally placed implants between: (1) implant level restorations, that underwent four ADs and (2) implants with immediate tissue level abutment with no AD, 1 month (T2) and 1-year (T3) after final restoration delivery.
Sixty-four patients received 64 bone level implants with platform-switching and conical connection in edentulous sites of posterior mandible and maxilla. All implants were placed 1.5 mm subcrestally and distributed among: (1) control group, that received a regular healing abutment and (2) test group with immediate tissue level (ITL) abutment, which was torqued to implants during surgery, transforming bone level implant to tissue level type. After 2-3 months of healing and a 1-month temporization, final zirconia-based screw-retained crowns were delivered to both groups. Crestal bone levels were calculated after final crown delivery (T2); after 1-year follow-up (T3) and compared using Mann-Whitney U test (p ≤ .05).
Early bone loss of the test and control groups was 0.14 ± 0.27 mm and 0.64 ± 0.64 mm, respectively; the 0.5 mm difference was statistically significant (p = .0001). Late bone loss was 0.06 ± 0.16 mm and 0.21 ± 0.56 mm for the test and control group, respectively; the 0.15 mm difference between the groups was no more statistically significant (p = .22). Both groups displayed bone gain, 0.08 and 0.43 mm, respectively, and the overall crestal bone loss was reduced.
Immediate tissue level abutments can significantly reduce early bone loss when measured 1 month after final prosthesis delivery, however, after 1-year follow-up, difference between the groups was no more statistically significant.
种植体基台连接体（AB）分离与牙槽骨吸收增加之间的关系仍存在争议。
比较骨嵴下放置的种植体在以下两种情况下种植体-基台交界处的骨变化：（1）经历了 4 次 AB 分离的种植体水平修复体，（2）无 AB 分离的种植体，在最终修复体交付后 1 个月（T2）和 1 年（T3）。
64 名患者在后牙区无牙颌下颌和上颌植入 64 枚具有平台转换和锥形连接的骨水平种植体。所有种植体均放置在骨嵴下 1.5mm 处，分布于：（1）对照组，植入常规愈合基台，（2）实验组植入即刻软组织水平（ITL）基台，在手术中旋入种植体，将骨水平种植体转换为软组织水平类型。愈合 2-3 个月并临时修复 1 个月后，两组均交付氧化锆螺钉固位冠。在最终冠交付后（T2）、1 年随访后（T3）测量牙槽嵴骨水平，并使用 Mann-Whitney U 检验进行比较（p≤0.05）。
实验组和对照组的早期骨损失分别为 0.14±0.27mm 和 0.64±0.64mm，两者相差 0.5mm，具有统计学意义（p=0.0001）。晚期骨损失分别为 0.06±0.16mm 和 0.21±0.56mm，组间相差 0.15mm，无统计学意义（p=0.22）。两组均有骨增量，分别为 0.08mm 和 0.43mm，总体牙槽骨吸收减少。
即刻软组织水平基台可显著减少最终修复体交付后 1 个月时的早期骨丢失，但 1 年后，组间差异无统计学意义。
