Alfonso Gil^1,*; Christoph Hämmerle¹; Franz Josef Strauss¹; Karin Wolleb²; Ronald Jung¹; Daniel Thoma¹

¹Clinic of Reconstructive Dentistry, University of Zurich; ²Private practice in Zurich, Zurich, Switzerland

Background: Shorter dental implants have expanded treatment options and reduced post-operative complications and patient morbidity. Further simplified treatments include cantilevers on dental implants. They offer high survival rates, similar to single implant-reconstructions. The combination of shorter dental implants with cantilevers decreases the surface to bear occlusal forces. Implant bone remodeling might adapt accordingly resulting in an increase in bone density, however such evidence is limited.

Aim/Hypothesis: To analyze changes in radiographic density of short implants with and without cantilevers after 5 years in function.

Material and Methods: Thirty-six patients with two missing posterior teeth participated in this randomized controlled clinical trial. All patients were randomly allocated to receive either two 6 mm one-piece implants with single unit restorations (group TWO) or one 6 mm one-piece implant with a cantilever restoration (group ONE-C). Patients were re-examined at 6 months, 1 year, 3 and 5 years. A radiographic analysis was performed, through an arbitrary grey scale value (GSV) of the peri-implant bone, evaluating the changes in radiodensity in between groups and over time. Descriptive statistics were applied, and differences were assessed with nonparametric methods (Wilcoxon-Mann-Whitney test).

Results: At 5 years, 26 patients remained in the study (15 in group ONE-C; 11 in group TWO). The survival rate amounted to 84.2% in ONE-C and to 80.4% in TWO (intergroup p=0.894). No restoration failures were observed for the implants re-examined at 5 years. The radiographic evaluation revealed higher GSV of group ONE-C (85.00) than group TWO (74.33) at 5-years follow-up (intergroup p=0.07). When changes in GSV were compared over time, group ONE-C showed a greater increase in radiodensity (13.50) than group TWO (4.16) (intragroup p < 0.0001). When arch location was considered, implants in the mandible showed an increase in GSV and implants in the maxilla a slight decrease over time.

Conclusion and Clinical implications: The radiodensity around short dental implants demonstrated to be higher and increase over time with cantilever restorations at 5 years, especially for those implants placed in the mandible.

Disclosure of Interest: None Declared

Keywords: implant stability, implant-supported restorations, short implants

阿方索·吉尔^1,* ; 克里斯托夫·哈默勒¹ ; 弗朗茨约瑟夫施特劳斯¹ ; 卡琳·沃勒布² ; 荣格¹ ; 丹尼尔·托马¹

¹苏黎世大学重建牙科诊所；²苏黎世私人执业，瑞士苏黎世

背景：较短的牙种植体扩大了治疗选择，减少了术后并发症和患者发病率。进一步简化的治疗包括牙种植体上的悬臂。它们提供高存活率，类似于单种植体重建。较短的牙种植体与悬臂的组合减少了承受咬合力的表面。种植体骨重塑可能会相应地进行调整，导致骨密度增加，但此类证据有限。

目的/假设：分析具有和不具有悬臂的短种植体在使用 5 年后的射线照相密度变化。

材料和方法： 36 名有两颗后牙缺失的患者参加了这项随机对照临床试验。所有患者被随机分配接受两个 6 mm 整体式修复体（第二组）或一个 6 mm 整体式种植体和悬臂修复体（组 ONE-C）。患者在 6 个月、1 年、3 和 5 年时再次接受检查。通过种植体周围骨的任意灰度值 (GSV) 进行放射照相分析，评估组间和随时间推移的放射密度变化。应用描述性统计，并用非参数方法（Wilcoxon-Mann-Whitney 检验）评估差异。

结果：在 5 年时，26 名患者仍留在研究中（ONE-C 组 15 名；第二组 11 名）。ONE-C 的存活率为 84.2%，而 TWO 的存活率为 80.4%（组间p = 0.894）。对于在 5 年时重新检查的种植体，没有观察到修复失败。放射学评估显示，在 5 年随访时，ONE-C 组 (85.00) 的 GSV 高于第二组 (74.33)（组间p = 0.07）。当 GSV 随时间的变化进行比较时，ONE-C 组的放射密度增加 (13.50) 比第二组 (4.16) 更大（组内p < 0.0001）。当考虑牙弓位置时，下颌骨的植入物显示 GSV 增加，而上颌骨的植入物随着时间的推移略有减少。

结论和临床意义：短牙种植体周围的辐射密度在 5 年时表现出更高，并随着时间的推移增加悬臂修复，尤其是那些放置在下颌骨的种植体。

利益披露：无申报

关键词: 种植体稳定性, 种植体支持修复体, 短种植体