1 INTRODUCTION

The integration and long-term success of dental implants exploit the unique biology of the oral cavity, which allows for osseous incorporation of a biomaterial and its long-term health within a bacteria-laden oral milieu.¹ The delicate balance of defense and repair mechanisms underlying this unique environment may be challenged by various factors that can act both locally and/or systemically, thereby increasing the risk of implant loss and jeopardizing the long-term success of inserted implants.

Local risk factors that are present in the oral cavity and systemic risk factors that have the potential to affect oral health on a systemic level can compromise implant treatment at all stages of treatment delivery by: (a) complicating surgical procedures and other invasive measures required during treatment; (b) compromising the process of tissue healing following implant insertion/increasing the risk of wound infection; and (c) contributing to the deterioration of long-term peri-implant health and tissue stability (Table 1).

TABLE 1. Effects of Systemic Diseases

Systemic conditions	Biologic effects	Potential to affect
		Surgical/invasive procedures	Tissue healing/risk of wound infection	Long-term peri-implant tissue health
Cardiovascular	Fatigue	x
Bleeding disorder	Innate/iatrogenic hypocoagulation	x	x	x
Osteoporosis	Reduced bone healing Reduced implant stability		x	x
Antiresorptive medication	Reduced bone remodeling Reduced angiogenesis Reduced bone regeneration		x	x
Diabetes mellitus	Acquired immunosuppression Hypovascularity		x	x
Rheumatoid disease	Iatrogenic immunosuppression		x	x
Organ transplantation			x	x
Crohn's disease			x	x
Chemotherapy	Iatrogenic immunosuppression Reduced tissue regeneration		x	x
HIV infection	Acquired immunosuppression		x	x
Tobacco abuse	Hypovascularity hypoxia Leukocyte dysfunction		x	x
Local conditions
Radiation therapy	Hypovascularity, hypocellularity, reduced tissue regeneration		x	x
Mucosal autoimmune diseases	Iatrogenic local immunosuppression		x	x

Conditions that interfere with invasive procedures, which include poor general health status (https://www.asahq.org/resources/clinical-information/asa-physical-status-classification-system) as a result of severe systemic disease, may impact upon implant surgery, healing, and maintenance. These are mostly cardiovascular conditions that can place the patient at high risk during surgery, irrespective of the nature of the intervention. Bleeding disorders, which may be innate or acquired, as well as attributable to the use of anticoagulants, may also complicate invasive measures. While the former are considered to be relatively rare, the latter may have a significant impact on daily implant treatment in an aging population.

Systemic and local factors that may compromise bone and soft tissue healing after implant insertion make up the majority of medical conditions that require consideration and/or management when contemplating implant therapy. The important systemic factors are:

• osteoporosis.
• anti-bone resorptive medications.
• diabetes mellitus.
• immune deficiency.
• behavioral factors such as substance abuse, in particular tobacco and alcohol.

Important local factors include:

• a history of radiation therapy.
• oral mucosal diseases.

All these conditions can also have a negative impact on long-term peri-implant health and maintenance of peri-implant tissues as a result of compromised vascularity, as well as alterations in the immune defense or repair capacity of peri-implant tissues.

The increasing patient demand for implant-based treatments in conjunction with a demographic shift of the patient population has resulted in a growing body of literature dealing with an increasing number of patients presenting with medical conditions. A recent cross-sectional analysis indicated that almost 90% of patients aged > 65 years were taking medication for underlying systemic diseases, which could jeopardize implant success.² The advent of new treatment modalities, such as antiresorptive drugs or monoclonal antibody therapies, adds to the number of potential risk factors,³ leading to an increasing challenge for the provision of implant-based treatments in the future. The aim of this narrative review was therefore to analyze the importance of systemic and local conditions as risk factors for implant loss by critically evaluating the available evidence. During evaluation of the available literature, it was obvious that the term “implant loss” was used to a much lesser degree than “implant failure.” Very few reports clearly defined implant failure as implant loss, but the context in which this term has historically been used indicates that implant failure was synonymous for implant loss. It is only in the last decade or so that definitions of implant failure have been published, and not until the 2017 World Workshop on Periodontal and Peri-Implant Disease Classification was an international definition agreed upon.⁴

One of the major reasons for implant loss is the progressive loss of peri-implant bone support. Therefore, marginal bone loss was also included in the analysis. As progressive crestal bone loss around implants in the absence of clinical signs of soft tissue inflammation is rare,⁵ reported radiographic bone loss was considered in conjunction with clinical peri-implant parameters (where provided) in the individual reports in order to assess the prognostic relevance of the findings.

中文翻译：

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全身性疾病和局部条件作为危险因素的作用

1 简介

牙科植入物的整合和长期成功利用了口腔独特的生物学特性，允许在充满细菌的口腔环境中骨结合生物材料及其长期健康。¹这种独特环境下的防御和修复机制的微妙平衡可能会受到各种因素的挑战，这些因素可以在局部和/或全身起作用，从而增加种植体丢失的风险并危及植入种植体的长期成功。

口腔中存在的局部风险因素和可能在全身水平上影响口腔健康的全身性风险因素可能会通过以下方式影响治疗实施各个阶段的种植体治疗：治疗; (b) 损害植入物插入后的组织愈合过程/增加伤口感染的风险；(c) 导致长期种植体周围健康和组织稳定性恶化（表 1）。

表 1.全身性疾病的影响

全身状况	生物效应	潜在影响
		手术/侵入​​性程序	组织愈合/伤口感染风险	长期种植体周围组织健康
心血管	疲劳	X
出血性疾病	先天性/医源性低凝	X	X	X
骨质疏松症	减少骨愈合 降低种植体稳定性		X	X
抗吸收药物	减少骨重塑 血管生成减少 减少骨再生		X	X
糖尿病	获得性免疫抑制 血管不足		X	X
类风湿病	医源性免疫抑制		X	X
器官移植			X	X
克罗恩病			X	X
化疗	医源性免疫抑制 减少组织再生		X	X
艾滋病毒感染	获得性免疫抑制		X	X
烟草滥用	缺氧缺氧 白细胞功能障碍		X	X
当地条件
放射治疗	血管减少、细胞减少、组织再生减少		X	X
粘膜自身免疫性疾病	医源性局部免疫抑制		X	X

干扰侵入性手术的情况，包括由于严重的全身性疾病导致的一般健康状况不佳 (https://www.asahq.org/resources/clinical-information/asa-physical-status-classification-system)，可能会影响在植入手术、愈合和维护时。这些主要是心血管疾病，无论干预的性质如何，都会使患者在手术期间处于高风险中。出血性疾病，可能是先天性或后天性的，以及可归因于使用抗凝剂，也可能使侵入性措施复杂化。虽然前者被认为相对罕见，但后者可能对老龄化人群的日常种植治疗产生重大影响。

植入物植入后可能影响骨骼和软组织愈合的全身和局部因素构成了在考虑植入物治疗时需要考虑和/或管理的大部分医疗条件。重要的系统性因素是：

• 骨质疏松症。
• 抗骨吸收药物。
• 糖尿病。
• 免疫缺陷。
• 行为因素，例如药物滥用，尤其是烟草和酒精。

重要的本地因素包括：

• 放射治疗史。
• 口腔黏膜疾病。

由于血管分布受损，以及免疫防御或种植体周围组织修复能力的改变，所有这些情况也会对种植体周围的长期健康和种植体周围组织的维护产生负面影响。

患者对基于植入物的治疗的需求不断增加，以及患者群体的人口结构变化，导致越来越多的文献涉及越来越多的患有医疗状况的患者。最近的一项横断面分析表明，几乎 90% 的年龄 > 65 岁的患者正在为潜在的全身性疾病服用药物，这可能会危及植入成功。²抗再吸收药物或单克隆抗体疗法等新治疗方式的出现增加了潜在风险因素的数量，³导致未来提供基于植入物的治疗面临越来越大的挑战。因此，本次叙述性审查的目的是通过严格评估现有证据来分析全身和局部条件作为种植体丢失风险因素的重要性。在评估现有文献时，很明显“种植体丢失”一词的使用程度远低于“种植体失败”。很少有报告将种植体失败明确定义为种植体丢失，但该术语历史上使用的上下文表明，种植体失败是种植体丢失的同义词。直到最近十年左右，种植体失败的定义才被公布，直到 2017 年世界牙周和种植体周围疾病分类研讨会才成为国际商定的定义。⁴

种植体丢失的主要原因之一是种植体周围骨支撑的逐渐丧失。因此，边际骨丢失也包括在分析中。由于在没有软组织炎症临床症状的情况下，种植体周围进行性牙槽嵴骨质流失是罕见的，为了评估预后相关性， ⁵份报告的放射学骨质流失与个体报告中的临床种植体周围参数（如果提供）一起考虑的调查结果。