Int J Oral Implantol (Berl). 2019;12(2):155-167.
To evaluate whether there are some clinical benefits by placing single dental implants either 0.5 mm or 1.5 mm subcrestally in healed bone crests.
Sixty partially edentulous patients requiring two single implant-supported crowns had both sites randomly allocated either to 0.5-mm or 1.5-mm subcrestal implant placement according to a split-mouth design at six centres and submerged in aesthetic areas or non-submerged in non-aesthetic areas for 3 months. Provisional acrylic crowns were delivered and were replaced after 2 months by definitive metal-ceramic crowns. Patients were followed to 3 years after loading. Outcome measures were: crown and implant failures, complications, aesthetics assessed using the pink aesthetic score (PES), peri-implant marginal bone level changes and patient preference, recorded by blinded assessors.
One patient dropped out. One patient lost both implants for infection at impression taking. Seven complications affected seven patients of the 0.5-mm group and four complications affected four patients of the 1.5-mm subcrestal group. Three patients had complications at both implants. There were no statistically significant differences for complications between group (OR = 4; 95% CI: 0.45 to 35.79; P (McNemar test) = 0.375). At delivery of definitive crowns, 2 months after loading, the mean PES was 11.22 ± 1.91 and 11.12 ± 1.59 for the 0.5- and 1.5-mm groups, respectively. At 1 year after loading, the mean PES was 12.09 ± 1.66 and 12.10 ± 1.52 for the 0.5- and 1.5-mm groups, respectively. At 3 years after loading, the mean PES was 11.99 ± 1.94 and 12.19 ± 1.78 for the 0.5- and 1.5-mm groups, respectively. There were no statistically significant differences between the two groups at 2 months (P = 0.626), at 1 year (P = 0.920) or at 3 years (P = 0.296). One year after loading, patients of the 0.5-mm group lost on average 0.21 ± 0.51 mm and those of the 1.5-mm group 0.11 ± 0.36 mm, the difference being not statistically significant (difference = 0.10 mm; 95% CI: -0.01 to 0.20; P = 0.078). Three years after loading, patients of the 0.5-mm group lost on average 0.34 ± 0.87 mm and those of the 1.5-mm group 0.19 ± 0.54 mm, the difference being statistically significant (difference = 0.15 mm; 95% CI: 0.00 to 0.30; P = 0.046). Patients did not prefer any depth of the implant placement over the other. There were no differences in outcomes between centres.
No appreciable clinical differences were noticed when placing implants 0.5 mm or 1.5 mm subcrestally; therefore clinicians can do as they prefer.
评估在愈合的牙槽嵴中，将单个牙种植体分别放置在牙槽嵴下 0.5 毫米或 1.5 毫米处是否具有临床优势。
60 名部分缺牙患者需要植入两颗单牙种植体支持的牙冠，他们的牙位随机分配到 6 个中心的 0.5 毫米或 1.5 毫米牙槽嵴下种植体放置组，根据分口设计，种植体在美学区域或非美学区域分别埋入 3 个月。在第 2 个月时，用临时丙烯酸冠替代，2 个月后用永久性金属-陶瓷冠替代。在加载后 3 年内对患者进行随访。观察指标为：牙冠和种植体失败、并发症、使用粉红美学评分（PES）评估的美学效果、种植体边缘骨水平变化和患者偏好，由盲法评估者记录。
1 名患者脱落。1 名患者在取印模时因感染失去了两颗种植体。7 例并发症影响了 0.5 毫米组的 7 名患者，4 例并发症影响了 1.5 毫米组的 4 名患者。3 名患者的两个种植体都有并发症。两组之间的并发症无统计学差异（OR = 4；95%CI：0.45 至 35.79；P（McNemar 检验）= 0.375）。在加载后 2 个月交付永久性牙冠时，0.5 毫米和 1.5 毫米组的平均 PES 分别为 11.22 ± 1.91 和 11.12 ± 1.59。加载后 1 年时，0.5 毫米和 1.5 毫米组的平均 PES 分别为 12.09 ± 1.66 和 12.10 ± 1.52。加载后 3 年时，0.5 毫米和 1.5 毫米组的平均 PES 分别为 11.99 ± 1.94 和 12.19 ± 1.78。两组在 2 个月时（P = 0.626）、1 年时（P = 0.920）或 3 年时（P = 0.296）均无统计学差异。加载后 1 年，0.5 毫米组的患者平均损失 0.21 ± 0.51 毫米，1.5 毫米组的患者平均损失 0.11 ± 0.36 毫米，差异无统计学意义（差值 = 0.10 毫米；95%CI：-0.01 至 0.20；P = 0.078）。加载后 3 年，0.5 毫米组的患者平均损失 0.34 ± 0.87 毫米，1.5 毫米组的患者平均损失 0.19 ± 0.54 毫米，差异有统计学意义（差值 = 0.15 毫米；95%CI：0.00 至 0.30；P = 0.046）。患者对种植体的放置深度没有明显偏好。各中心的治疗结果无差异。
将种植体分别放置在牙槽嵴下 0.5 毫米或 1.5 毫米处，没有明显的临床差异；因此，临床医生可以根据自己的喜好进行操作。
