Andersson Bernt, Bergenblock Sibel, Fürst Björn, Jemt Torsten
Specialist Clinic of Prosthetic Dentistry, Public Dental Health Service, Mölndal Hospital, Västra Götaland, Sweden.
Clin Implant Dent Relat Res. 2013 Aug;15(4):471-80. doi: 10.1111/j.1708-8208.2011.00381.x. Epub 2011 Aug 11.
Various levels of infraposition of single-implant restorations have been observed in long-term follow-up studies, but little knowledge is available on the biological mechanism behind this pattern.
The primary aim of this study is to report the frequency and severeness of implant infraposition in the anterior single-implant application after 17 to 19 years in function and, secondly, to try to relate these observations to anatomical appearance of the shape of the face of the patient.
The present study comprised of 57 patients who were provided with 65 CeraOne™ single-tooth restorations (Nobel Biocare AB, Gothenburg, Sweden) between 1989 and 1991. Altogether 46 of these patients were treated with single implants in the anterior region. Besides clinical and radiographic data, clinical photographs, study casts, and patient's assessment of the long-term aesthetic result (visual analog scale) was collected at the termination of the present study. The degree of implant crown infraposition was related to assessed facial shape and to patient and clinical assessment of the aesthetic result by means of Pearson's correlation test. To increase the numbers of patients, another group of 25 patients presented in another similar study were pooled with the present material for prevalence calculations.
Altogether 47 patients showed up for the final examination after an average of 18 years (82%). Two implants failed (18 years cumulative survival rates [CSR]- 96.8%) and eight original single-crown restorations were replaced (CSR 83.8%). Three of the replaced crowns were replaced because of infraposition of the crowns. About 40% of the patients showed signs of infraposition, similar in younger and older age groups, but more frequently observed in female patients at termination of the study (p < 0.05). There was a weak trend indicating an association between "long-face" appearance and infraposition of the crown restoration (p > 0.05), and patients were more satisfied with the aesthetic clinical result than the participating clinicians (p < 0.05).
Single-implant restorations in the anterior upper jaw may present small degrees of infraposition in long-term perspectives. Female patients seem to be at a higher risk of infraposition (p < 0.05), but no clear relationship between age at implant placement or facial shape and degree of infraposition was possible to establish (p > 0.05). Patients were more satisfied with the aesthetic result, as compared with the clinicians (p < 0.05), and patients seemed to pay less attention to the degree of infraposition in their aesthetic assessments, as compared with most of the clinicians.
在长期随访研究中观察到单颗种植体修复体存在不同程度的低位，但对于这种模式背后的生物学机制知之甚少。
本研究的主要目的是报告功能17至19年后前牙单颗种植体应用中种植体低位的频率和严重程度，其次，尝试将这些观察结果与患者面部形状的解剖外观相关联。
本研究纳入了1989年至1991年间接受65颗CeraOne™单颗牙修复体（诺贝尔生物保健公司，瑞典哥德堡）的57例患者。其中46例患者在前牙区接受单颗种植体治疗。除临床和影像学数据外，在本研究结束时收集了临床照片、研究模型以及患者对长期美学效果的评估（视觉模拟量表）。通过Pearson相关检验，将种植体冠低位程度与评估的面部形状以及患者和临床对美学效果的评估相关联。为增加患者数量，将另一项类似研究中的25例患者与本研究材料合并进行患病率计算。
共有47例患者在平均18年后前来进行最终检查（82%）。两颗种植体失败（18年累积生存率[CSR] - 96.8%），八颗原单冠修复体被替换（CSR 83.8%）。其中三颗被替换的冠是因为冠的低位而被替换。约40%的患者出现低位迹象，在年轻和老年组中相似，但在研究结束时女性患者中更常见（p < 0.05）。有微弱趋势表明“长脸”外观与冠修复体低位之间存在关联（p > 0.05），并且患者对美学临床结果的满意度高于参与的临床医生（p < 0.05）。
从长期来看，上前牙单颗种植体修复体可能会出现小程度的低位。女性患者似乎有更高的低位风险（p < 0.05），但无法确定种植时的年龄或面部形状与低位程度之间的明确关系（p > 0.05）。与临床医生相比，患者对美学结果更满意（p < 0.05），并且与大多数临床医生相比，患者在美学评估中似乎较少关注低位程度。
