Heeje Lee D.D.S.; Alika Yu DDS
In the absence of modifying factors, the evidence supports early and immediate loading protocols for mandibular posterior implants.
Considering the design of original studies, patient selection may play an important role to obtain such a high implant survival rate.
Do early and immediately loaded micro-roughened implants placed in the mandibular posterior region differ in their success and survival rates, as well as marginal bone level changes, in the absence of modifying factors?
The authors searched two electronic databases for English-only articles published up to May 2008. They also hand searched five journals and other resources. The initial search yielded 426 articles, of which 35 were selected for further review. The authors excluded studies that included: immediate placement into the extraction sockets, guided bone regeneration, and/or full-arch reconstructions. The authors selected a total of 19 papers for inclusion in this systematic review. The outcome measures were survival rate, success rate and marginal bone loss.
The 19 articles comprised eight studies that examined early loading protocols, nine that examined immediate loading protocols, and two that compared both protocols. Five studies were RCTs and 14 were prospective clinical trials. In the early loading studies, various loading-time protocols were applied from nine days to 12 weeks after implant placement, but most implants were loaded between three and six weeks after surgery. The authors reported on a total of 943 early loading implants. There were 12 early failures (1.3 percent) and four after-loading failures (0.4 percent). The only study that examined early loading of machined-surface implants reported a 2 percent failure rate. The failure rate of the immediately loaded implants (a total of 590 implants) was 4.1 percent. Among the 11 studies of immediate loading protocols, three studies that investigated machined-surface implants reported a failure rate of 10.2 percent.
The evidence supports early and immediate loading of micro-roughened dental implants in the partial edentulous posterior mandible.
Source of Funding:
The current systematic review was supported by International Team for Implantology (ITI). None of the authors reported a conflict of interest.
Importance and Context:
Patient comfort can be improved by shortening the time between placing an implant and loading the restoration. Bioengineering of the fixture surface appears to affect the behavior of surrounding bone cells1 and can be a consideration when deciding to pursue early implant loading.
Strengths and Weaknesses of the Systematic review: The authors used accepted methods to conduct this systematic review. They searched multiple databases. Multiple authors reviewed the included studies. The authors weakened their systematic review by including English-only publications; by not providing a rationale for not combining the results through a meta-analysis, and by not assessing the studies for publication bias.
Strengths and Weaknesses of the Systematic Review:
The authors used accepted methods to conduct this systematic review. They searched multiple databases. Multiple authors reviewed the included studies. The authors weakened their systematic review by including English-only publications; by not providing a rationale for not combining the results through a meta-analysis, and by not assessing the studies for publication bias.
Strengths and Weaknesses of the Evidence:
The authors included 19 articles, of which only five were RCTs and the others prospective clinical trials. Based on the included studies, the survival rate of the posterior mandibular implants, either early or immediately loaded, was consistently high. The following factors limited their findings: most of the original studies the authors included were prospective observations without a control group; and they did not address part of the clinical question by failing to make a direct statistical comparison between the variables of early- and immediate loading protocols.
Implications for Dental Practice:
The survival rate of micro-roughened implants, whether early or immediately loaded in the posterior mandible, was quite high in the absence of modifying factors. However, these favorable outcomes were obtained from studies that had specific criteria for selection of patients for immediate/early loading. A recent review from the Cochrane oral health group that assessed different times for loading implants (not limited to the posterior region) did not find a statistically significant difference in implant survival rate between the early, immediate and conventional loading. The estimates of failure rates (relative risk data) from that review suggests that the risk associated with immediate and early loading tends to be higher than with conventional loading