Int J Oral Maxillofac Implants. 2011 Nov-Dec;26(6):1333-43.
The purpose of this retrospective study was to evaluate the medium- to long-term clinical outcome of single-tooth implants placed into fresh extraction sockets using a low-insertion-torque protocol and immediately restored with acrylic resin provisional crowns.
Sixty-one patients consecutively referred for the replacement of one or more failing teeth were planned for treatment by means of extraction and immediate implant placement and provisionalization using a low-insertion-torque protocol of ≤ 25 Ncm. Low rotational stability was not a contraindication to treatment unless there was a lack of axial stability. Implant survival and marginal bone levels were documented. A statistical analysis was performed to discover any correlations between insertion torque, age, gender, implant size and tooth position and marginal bone loss.
Sixty-eight implants were placed. Three implants failed to osseointegrate; one was replaced and immediately restored and has been successful for more than 5 years. The overall survival rate for all implants was 95.5%, which have been in function for a period of 1.25 to 9.5 years. The mean marginal bone loss of the 54 implants followed for at least 24 months was 0.23 ± 0.60 mm mesially and 0.20 ± 0.72 mm distally. Overall, 78% of implants showed no marginal bone loss, 9% experienced 0.1 to 0.5 mm of bone loss, and 13% demonstrated > 0.5 mm of bone loss. There were no significant correlations between the various parameters analyzed and marginal bone loss.
A torque of only 25 Ncm would seem more than sufficient to yield a favorable clinical outcome, and there may be a misconception as to what actually represents adequate primary stability. Immediate provisionalization of single-tooth implants placed with a relatively low insertion torque can yield favorable survival rates and optimal maintenance of marginal bone levels compared to the generally accepted norm.
本回顾性研究的目的是评估使用低植入扭矩方案将单颗牙种植体植入新鲜拔牙窝中，并使用丙烯酸树脂临时冠即刻修复的中至长期临床效果。
连续 61 名患者因一颗或多颗失败牙齿的替换而被计划接受治疗，方法是采用低植入扭矩方案（≤25 Ncm）进行拔牙和即刻种植体植入及临时修复。低旋转稳定性不是治疗的禁忌症，除非轴向稳定性不足。记录种植体的存活率和边缘骨水平。进行了统计分析，以发现植入扭矩、年龄、性别、种植体尺寸和牙齿位置与边缘骨丢失之间的任何相关性。
共植入 68 颗种植体。有 3 颗种植体未能骨整合，其中 1 颗已更换并立即修复，已成功使用超过 5 年。所有种植体的总体存活率为 95.5%，已使用 1.25 至 9.5 年。至少随访 24 个月的 54 颗种植体的平均边缘骨丢失为近中侧 0.23 ± 0.60mm，远中侧 0.20 ± 0.72mm。总体而言，78%的种植体无边缘骨丢失，9%的种植体边缘骨丢失 0.1 至 0.5mm，13%的种植体边缘骨丢失>0.5mm。分析的各种参数与边缘骨丢失之间均无显著相关性。
仅 25 Ncm 的扭矩似乎足以获得良好的临床效果，并且对于什么是实际代表足够的初始稳定性可能存在误解。与普遍接受的标准相比，使用相对较低的植入扭矩即刻修复单颗牙种植体可获得较高的存活率和最佳的边缘骨水平维持。
