Ottoni Judith Maria Pinheiro, Oliveira Zilda Fagundes Lima, Mansini Roberto, Cabral Antonio Melo
Brazilian Association of Odontology, Vitória, Espirito Santo, Brazil.
Int J Oral Maxillofac Implants. 2005 Sep-Oct;20(5):769-76.
This study evaluated the survival parameters of single-tooth implants through clinical and radiographic analysis.
Implants were restored within a 24-hour period with a provisional crown designed to receive an occlusal masticatory load. This approach was compared to implants restored after a healing period (the control group). Forty-six implants were placed in 23 patients who were each treated with 2 Frialit-2 implants placed in sites between the second premolar in the maxilla or mandible. The manufacturer's recommended formal surgical procedure was followed, and primary stability was standardized with a minimum insertion torque of 20 Ncm. The sites were randomly selected, and the clinical and radiographic parameters were standardized with individual templates.
Data were collected at 24 h, and at 1, 3, 6, 12, 18, and 24 months. The experimental group included 10 failed implants; 9 of the failed implants had been placed with an insertion torque of 20 Ncm. One implant from the control group failed during the 24-month follow-up period. The survival rate was independent of implant length, site position, and bone quality and quantity. Relative risk for implant failure was associated with insertion torque (relative risk 0.79 [CI: 0.66-0.930]; Cox regression) (P < or = .007), in the experimental group but was not significant for those in the control group (ie, implants placed after a healing period; relative risk 0.78 [CI: 0.34-1.78]; Cox regression) (P < or = .057). To achieve osseointegration, it was found that an insertion torque above 32 Ncm was necessary (chi2= 15.68; P < or = .004).
A careful evaluation is necessary for a better understanding of the survival rates of immediately loaded implants. In this study, insertion torque was associated with the potential for risk, which can be decreased by 20% per 9.8 Ncm added.
Given these results, and considering the number of patients treated, immediate provisional crowns should only be proposed with early loading if an appropriate initial insertion torque has been applied.
本研究通过临床和影像学分析评估单颗牙种植体的生存参数。
种植体在24小时内用设计用于承受咬合咀嚼负荷的临时冠进行修复。将这种方法与愈合期后修复的种植体（对照组）进行比较。46颗种植体植入23例患者体内，每位患者在上颌或下颌第二前磨牙之间的部位植入2颗Frialit-2种植体。遵循制造商推荐的正式手术程序，以至少20 Ncm的植入扭矩使初期稳定性标准化。随机选择种植部位，并用个体化模板使临床和影像学参数标准化。
在24小时、1、3、6、12、18和24个月时收集数据。实验组有10颗种植体失败；其中9颗失败种植体的植入扭矩为20 Ncm。对照组有1颗种植体在24个月的随访期内失败。生存率与种植体长、部位位置以及骨质量和骨量无关。实验组中种植体失败的相对风险与植入扭矩相关（相对风险0.79 [可信区间：0.66 - 0.930]；Cox回归）（P≤0.007），但对照组中则不显著（即愈合期后植入的种植体；相对风险0.78 [可信区间：0.34 - 1.78]；Cox回归）（P≤0.057）。为实现骨结合，发现植入扭矩高于32 Ncm是必要的（卡方 = 15.68；P≤0.004）。
为更好地了解即刻负重种植体的生存率，需要进行仔细评估。在本研究中，植入扭矩与风险可能性相关，每增加9.8 Ncm可使风险降低20%。
鉴于这些结果，并考虑到治疗的患者数量，只有在施加了适当的初始植入扭矩时，才应在早期负重的情况下建议即刻使用临时冠。
