Dental School, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Porto Alegre, Brazil.
Dental School, Federal University of Santa Catarina (UFSC), Florianópolis, Brazil.
Clin Implant Dent Relat Res. 2017 Aug;19(4):671-680. doi: 10.1111/cid.12494. Epub 2017 May 10.
The use of short implants is still not a consensus for challenging clinical situations, such as unfavorable crown-to-implant (C/I) ratio.
This prospective study evaluated the rates of prosthetic complications and implant failure, the mean marginal bone loss of 6-mm dental implants with single crowns in posterior regions and the potential risk factors.
Forty-six dental implants, 6-mm long and 4.1-mm wide, were placed in the posterior region in 20 patients. Patients were clinically and radiographically examined after the restoration with single crowns and on a yearly basis. Potential risk factors (arch, bruxism, maximum bite force, anatomical and clinical C/I ratios, and occlusal table area) were analyzed according to the following outcomes: implant survival, bone loss, and prosthetic complications.
The mean follow-up time was 45 ± 9 (16-57) months. There was no early loss of implants. After prosthetic loading, 4 implants were lost (2 in the mandible and 2 in the maxilla; 91.3% survival), and there were 13 prosthetic complications (28.3%), yielding a 65.2% success rate. The frailty term showed a 95% greater chance of loss in the mandible than the maxilla. Mean peri-implant bone loss was of 0.2 ± 0.4 mm, 0.1 ± 0.2 mm, 0.1 ± 0.3 mm, and 0.2 ± 0.4 mm in the first, second, third, and fourth years, respectively, with a mean cumulative loss of 0.3 ± 0.5 mm at 48 months. In the multilevel model, the effects of the clinical C/I ratio and time were significant for bone loss (P < .001). It was estimated that a mean bone loss of 0.1 mm is associated with both a one-unit increase in time (12 months) and a 0.1 increase in the clinical C/I ratio. The other potential risk factors showed no significant relationship with the outcomes.
The 6-mm implants supporting single crowns performed well, but the mandible shows a higher risk of failure. The time and clinical C/I ratio are predictors for bone loss.
在诸如不利的冠根比等具有挑战性的临床情况下，使用短种植体仍然没有达成共识。
本前瞻性研究评估了后牙区 6 毫米长、4.1 毫米宽单冠种植体的修复体并发症和种植体失败率、平均边缘骨丧失以及潜在的风险因素。
20 例患者的后牙区共植入 46 颗 6 毫米长、4.1 毫米宽的种植体。在修复体完成后以及每年，对患者进行临床和影像学检查。根据以下结果分析潜在的风险因素（牙弓、磨牙症、最大咬合力、解剖和临床冠根比以及咬合面面积）：种植体存活率、骨丧失和修复体并发症。
平均随访时间为 45±9（16-57）个月。没有早期种植体丢失。修复体加载后，有 4 颗种植体（下颌 2 颗，上颌 2 颗；存活率 91.3%）丢失，有 13 颗修复体发生并发症（28.3%），成功率为 65.2%。脆弱性术语表明下颌发生丢失的几率比上颌高 95%。种植体周围骨平均丧失量分别为第一年 0.2±0.4 毫米、第二年 0.1±0.2 毫米、第三年 0.1±0.3 毫米和第四年 0.2±0.4 毫米，48 个月时累积平均骨丧失量为 0.3±0.5 毫米。在多水平模型中，临床冠根比和时间对骨丢失有显著影响（P<.001）。据估计，时间（12 个月）和临床冠根比各增加 1 个单位，骨丢失量平均增加 0.1 毫米。其他潜在的风险因素与结果无显著关系。
6 毫米种植体支持单冠效果良好，但下颌的失败风险较高。时间和临床冠根比是骨丢失的预测因素。
