Periodontol 2000. 2014 Oct;66(1):153-87. doi: 10.1111/prd.12040.
The introduction of immediate loading was a paradigm shift in implant dentistry as it was previously believed that an unloaded period was essential for bone healing in order to promote osseointegration. However, this belief could not be confirmed by clinical studies or by human histology. Hitherto, numerous reports have been published on immediate loading in various indications. An important factor for success is primary implant stability. The latter can be improved by adapting drilling protocols to enhance lateral compression of the bone and by using tapered implant designs with apical thread fixation. To some extent, the use of implants with a microrough surface and rigid splinting may compensate for suboptimal stability. It is important to avoid fracture of the provisional restoration at all times as this may result in local overloading and implant failure. Also, unevenly distributed occlusal contacts may contribute to failure and therefore occlusion ought to be evaluated at every occasion, especially during the early phase of healing. Taking these aspects into account, immediate loading in the fully edentulous mandible by means of an overdenture has been shown to be predictable in terms of implant survival (94.4-100%). However, the procedure may result in additional costs as a result of the need for repeated relining. In addition, the scientific basis for this treatment concept in the maxilla is very scarce. Immediate loading in the fully edentulous jaw by means of a fixed prosthesis is a well-documented treatment concept. In the mandible, three implants have been shown to be insufficient, given the failure rate of up to 10%. With at least four implants a failure rate of 0-3.3% may be expected. In the maxilla, four to six implants could be too limited, given the failure rate up to 7.2%. Increasing the number of implants may reduce implant failure to 3.3%. Provisional fixed prostheses are particularly prone to fracture in the maxilla and hence reinforcement is warranted. Immediately loaded single implants have lower survival rates, of 85.7-100%, with no clear impact of occlusal contact. In fact, a meta-analysis demonstrated a five times higher risk of failure for immediately loaded single implants when compared with delayed loading. No study showed superior soft-tissue preservation or esthetics following immediate loading of single implants compared with other loading protocols. However, this finding may not imply that a provisional implant crown becomes redundant when soft-tissue conditioning is deemed necessary. Taking into account earlier factors for success, immediate loading in the partially edentulous jaw by means of a fixed prosthesis seems predictable in terms of implant survival (95.5-100%). However, there are no studies with data on soft-tissue parameters, esthetic aspects or patient-centered outcomes, and the available studies mainly relate to the load-carrying part of the dentition. Clinical studies focusing on these aspects of treatment outcome are clearly needed. High patient satisfaction is the most important advantage of immediate loading, especially during the early healing phase. In this context, one should also realize that studies have revealed comparable patient satisfaction in patients following delayed loading once their prosthesis is in place. In the decision-making process, this aspect should be properly discussed with the patient along with other advantages and disadvantages of immediate loading.
即刻负载的引入是种植体牙科的一个范式转变，因为以前人们认为，为了促进骨整合，需要一个无负载期。然而，这一信念不能被临床研究或人类组织学所证实。迄今为止，已经有许多关于各种适应证即刻负载的报告。成功的一个重要因素是初始种植体稳定性。后者可以通过调整钻孔方案来提高，以增强骨的侧向压缩，并使用具有根尖螺纹固定的锥形种植体设计。在某种程度上，使用具有微粗糙表面和刚性夹板的种植体可以弥补稳定性不理想的问题。重要的是，始终要避免临时修复体的断裂，因为这可能导致局部过载和种植体失败。此外，不均匀分布的咬合接触也可能导致失败，因此在每次咬合时都应进行评估，尤其是在愈合的早期阶段。考虑到这些方面，通过覆盖义齿在完全无牙的下颌骨中进行即刻负载，在种植体存活率方面（94.4-100%）已经被证明是可预测的。然而，由于需要反复衬垫，该程序可能会导致额外的费用。此外，上颌骨中这种治疗概念的科学基础非常匮乏。通过固定义齿在完全无牙的下颌骨中进行即刻负载是一种有充分文献记载的治疗概念。在下颌骨中，由于失败率高达 10%，三枚种植体被证明是不够的。使用至少四枚种植体，预计失败率为 0-3.3%。在上颌骨中，由于失败率高达 7.2%，四到六枚种植体可能过于局限。增加种植体的数量可以将种植体失败率降低至 3.3%。临时固定义齿在上颌骨中特别容易断裂，因此需要加固。即刻负载的单枚种植体的存活率较低，为 85.7-100%，而咬合接触没有明显影响。事实上，一项荟萃分析表明，与延迟加载相比，即刻加载的单枚种植体失败的风险高五倍。没有研究表明，与其他加载方案相比，即刻加载单枚种植体在软组织保存或美观方面具有优势。然而，这一发现并不意味着在认为需要软组织调理时，临时种植体冠就变得多余了。考虑到早期成功的因素，通过固定义齿在上颌骨的部分缺牙中进行即刻负载在种植体存活率方面似乎是可预测的（95.5-100%）。然而，目前还没有关于软组织参数、美观方面或以患者为中心的结果的研究，并且现有的研究主要涉及牙齿的承载部分。显然需要进行侧重于这些治疗结果方面的临床研究。患者满意度高是即刻负载的最重要优势，尤其是在早期愈合阶段。在这方面，还应该意识到，一旦患者的义齿就位，研究表明，延迟加载的患者的满意度也相当高。在决策过程中，应该与患者一起讨论这一方面，以及即刻负载的其他优缺点。
