Int J Oral Maxillofac Implants. 2019 November/December;34(6):1347–1358. doi: 10.11607/jomi.7526. Epub 2019 Apr 1.
Implants in the anterior region are challenging, and literature reporting outcomes of narrow-diameter implants (NDIs) in anterior sites is scarce. This systematic review summarized evidence of functional and esthetic performance of anterior single crowns supported by NDIs.
Ten databases were searched to find studies evaluating anterior single crowns supported by NDIs. Risk of bias was assessed, and random-effects meta-analyses were applied to analyze mean differences in survival, success, and marginal bone level (MBL). The review was registered in the PROSPERO database (CRD42018089886).
Twenty-one studies meeting the screening criteria were included for qualitative analysis, and three for meta-analysis. A total of 892 NDIs, placed in 736 patients, were analyzed. Follow-up duration varied from 12 months to 14 years (mean: 40 months), and 16 failures (implant loss) were recorded. Fixed-effect meta-analysis (I = 0%) of survival rate revealed a risk difference of 0.02 (95% CI: -0.03 to 0.08), between NDIs and controls (regular-diameter implants), without differences between groups (P = .39). Success rates ranged from 84.2% to 100% (mean: 95.2%). Random-effects meta-analysis (I = 56%) of MBL indicated a mean difference of 0.02 mm (95% CI: -0.21 to 0.25), without differences between groups (P = .87).
Single crowns supported by NDIs are a predictable treatment, since their survival rate and MBL are comparable to those supported by regular-diameter implants. Due to data shortage reporting esthetic outcomes, more studies are needed to evaluate the long-term performance of the single crowns supported by NDIs in the anterior region.
前牙区种植存在挑战，且目前关于小直径种植体（NDI）在前牙区应用效果的文献报道较少。本系统综述总结了 NDI 支持的前牙单冠在功能和美观性能方面的证据。
检索了 10 个数据库以寻找评估 NDI 支持的前牙单冠的研究。评估了偏倚风险，并应用随机效应荟萃分析分析了生存率、成功率和边缘骨水平（MBL）的均值差异。该综述已在 PROSPERO 数据库（CRD42018089886）中注册。
符合筛选标准的 21 项研究被纳入定性分析，3 项研究进行了荟萃分析。共分析了 892 颗 NDI，涉及 736 名患者。随访时间从 12 个月到 14 年不等（平均：40 个月），记录了 16 例（种植体丧失）失败病例。生存率的固定效应荟萃分析（I = 0%）显示，NDI 与对照组（常规直径种植体）之间的风险差异为 0.02（95%CI：-0.03 至 0.08），两组之间无差异（P =.39）。成功率范围为 84.2%至 100%（平均：95.2%）。MBL 的随机效应荟萃分析（I = 56%）表明，平均差异为 0.02mm（95%CI：-0.21 至 0.25），两组之间无差异（P =.87）。
NDI 支持的单冠是一种可预测的治疗方法，因为其生存率和 MBL 与常规直径种植体支持的单冠相当。由于缺乏报告美学效果的数据，需要更多的研究来评估 NDI 在前牙区支持的单冠的长期性能。
