Gerard Byrne BDSc MSD
There is not enough evidence to recommend the immediate loading of single tooth implants.
Immediately loaded single implants(with crowns) are at higher risk of failure than conventionally loaded implants.
What is the implant survival rate for immediately loaded single implants (with crowns) and conventionally loaded implants?
The authors searched two electronic databases up until Nov 1 2007, restricted to articles in English. They also completed an extensive manual search of the literature. The search and screening process was carried out by two independent reviewers. Randomized controlled trials and controlled clinical trials with a minimum of 10 single implants and a minimum of 6 months follow-up were selected. The review isolated implant studies with single crown usage only (incisor, canine and premolar areas) comparing conventional and immediate implant loading modalities. The outcome assessed was implant survival. The authors assessed the heterogeneity and publication bias of studies. They conducted a meta-analysis in accordance with PRISMA guidelines
Five studies were selected for analysis, 2 RCTs and 3 controlled clinical trials, with a total of 248 implants. All studies compared single implant crown cases with immediate and conventional loading. Immediate loading of implants involved occlusal loading/contact in only one of the five studies. Studies (6 - 24 mt duration) were found to be homogeneous and meta-analysis was conducted for implant survival. There was a greater risk for failure of immediately loaded implants compared to conventionally loaded implants (RR:5.00,95%CI:2.00 to 12.84,P
Better outcomes are achieved with conventional loading of single implants with crowns, as opposed to immediately loaded implants, which carry a higher risk of failure.
Source of Funding:
Importance and Context:
Traditional implant placement protocols call for a healing period of 8-12 months after extraction, and an unloaded healing period of 3-6 months. In line with patient desires for shorter treatment time, and in an attempt to optimize esthetics, clinicians have gradually attempted to place implants in extraction sites and/or load them immediately or soon after placement. Immediate loading requires good surgical implant stability permitting the connection of a provisional restoration which may favor more ideal soft tissue healing. ‘Immediate loading’ implies loading at the time of surgery, whereas the term ‘early loading’ is not well defined.
Strengths and Weaknesses of the Systematic Review:
This is a good systematic review that used accepted methods to identify and select studies presenting information that could be used to address the clinical question. Selection criteria were rigorously applied, yielding just five studies for review; consequently the studies showed good homogeneity for meta-analysis. The outcome parameter is clear; implant survival with immediate and conventional loading. However, bone levels are mentioned in four of the five studies but data are not presented. It is not clear from the data how the authors came to the conclusion that there were no significant differences between the groups in any of the studies.
Strengths and Weaknesses of the Evidence:
The selected studies were homogeneous and well suited to meta-analysis. However, the studies were of very short duration and small sample size. Only one study (RCT) had adequate allocation concealment. Criteria for implant site selection were not enumerated i.e. extraction and non-extraction.
Little information was presented on implant stability/torque values prior the attachment of provisional crowns; details of torque values for implants/provisional crown connection/loading are important for compararisons and may determine success/failure. Although aesthetic outcomes are central to the rationale for 'immediate' placement and loading of implants, they were not addressed.
Implications for Dental Practice:
Limited evidence indicates a higher failure rate for immediately loaded implants compared with conventionally loaded implant crowns. The conventional implant protocol has a more predictable implant prognosis. The potential risks of immediate loading should be communicated to patients in these cases.