Department of Prosthodontics, Oregon Health Sciences University, Portland, Oregon, USA.
Int J Oral Maxillofac Implants. 2012 Jul-Aug;27(4):945-56.
The primary goal of this stratified randomized controlled trial (SRCT) was to compare the stability of dental implants placed under three different loading regimens during the first 16 weeks of healing following implant placement. Implants were loaded immediately, early (6 weeks), or with conventional/delayed timing (12 weeks). Secondary outcomes were to compare marginal bone adaptation for 3 years after placement.
Single posterior implant sites in the maxilla or mandible were examined. The insertion torque value was the primary determinant of load assignment. Resonance frequency analysis was performed at follow-up appointments for the first 16 weeks (with results provided as implant stability quotients [ISQs]). Marginal bone levels were assessed via radiographs.
Forty patients each received a single 4.0-mm diameter dental implant between 2004 and 2007. One implant failure occurred in Lekholm and Zarb type 4 bone with insertion torque value (ITV) of < 8.1 Ncm; the cumulative success rate was 97.5%. All implants, when classified by bone and loading type, increased in stability over time, with a minor reduction of 1.3 ISQ units seen at 4 weeks in the immediate loading group. The mean marginal bone loss over 3 years was 0.22 mm. The mean ITVs at implant placement for bone types 1 and 2 (grouped together), 3, and 4 were 32, 17, and 10, respectively, and were significantly different (P < .05).
ITV was a good objective measure of bone type. Using an ITV of 20 Ncm as the determinant for immediate loading and an ITV of 10 Ncm or greater as the determinant for early loading provided long-term success for this implant and led to no negative changes in tissue response. All bone type groups and loading groups showed no reduction in stability during the first 4 months of healing.
本分层随机对照试验（SRCT）的主要目的是比较在种植体植入后 16 周的愈合期内，采用三种不同加载方案对种植体的稳定性。种植体即刻加载、早期（6 周）或传统/延迟加载（12 周）。次要结果是比较种植体放置后 3 年的边缘骨适应性。
研究对象为上颌或下颌单颗后牙种植体位点。种植体植入时的初始扭矩值是决定加载方案的主要因素。在最初的 16 周内，通过随访检查进行共振频率分析（结果以种植体稳定性比[ISQ]表示）。通过放射学评估边缘骨水平。
2004 年至 2007 年间，40 名患者每人植入一颗 4.0 毫米直径的牙科种植体。在勒科姆和扎布 4 型骨中，植入扭矩值（ITV）<8.1 Ncm 时发生 1 例种植体失败，累积成功率为 97.5%。所有种植体，按骨类型和加载类型分类，随时间推移稳定性增加，即刻加载组在 4 周时略有下降 1.3 ISQ 单位。3 年的平均边缘骨丢失量为 0.22 毫米。骨类型 1 和 2（合并）、3 和 4 的种植体植入时平均 ITV 分别为 32、17 和 10，差异有统计学意义（P<.05）。
ITV 是骨类型的良好客观指标。使用 20 Ncm 的 ITV 作为即刻加载的决定因素，使用 10 Ncm 或更大的 ITV 作为早期加载的决定因素，为该种植体提供了长期成功，并导致组织反应没有负面变化。所有骨类型组和加载组在愈合的前 4 个月内稳定性没有下降。
