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Associated Topics

Based on limited evidence, early or immediate loading protocols achieve implant survival rates comparable to conventional loading protocol for mandibular implant overdentures

Heeje Lee D.D.S. .


Systematic Review Conclusion

Early or immediate loading protocols for mandibular implant overdentures were as successful as conventional loading one for up to 24 months.

Critical Summary Assessment

This high quality systematic review, which included a meta-analysis, requires careful interpretation due to limited number of selected studies and patients.

Evidence Quality Rating

Limited Evidence

Structured Abstract

Clinical Questions:

In patients receiving mandibular implant overdentures, do early or immediate loading protocols with mandibular implant overdentures result in survival rates comparable to those of the conventional implant loading protocol?

Review Methods:

The authors searched four electronic databases for articles published up to October 2008. They also hand searched 15 dental journals. The clearly defined inclusion criteria were clinical trials that had a minimum follow-up period of 24 months. The authors used the Cochran criteria for loading protocols1 instead of the protocol defined in the original studies. Two reviewers independently collected and extracted data. The authors assessed the quality of the studies and conducted meta-analysis.

Main Results:

The initial search yielded 191 articles, of which 19 were selected for full-text review. Nine articles were excluded after the second review; the remaining 10 articles were included for meta-analysis. Seven articles compared conventional (n = 84) with early loading (n = 85) and three articles compared conventional (n = 29) with immediate loading (n = 37). The meta-analysis reported that there was no significant difference in implant survival rate between either conventional and early or conventional and immediate loading protocol after 24 months. No publication bias was found for both comparisons.


Both early and immediate loading protocols for mandibular overdenture achieved comparable implant survival in comparison to conventional loading for up to 24 months.

Source of Funding:

None stated.


Importance and Context:

Long-term clinical studies have reported high implant survival rates for mandibular implant overdentures with the conventional loading protocol.2 To reduce the duration of treatment, modified loading protocols (early or immediate) and their variations have been developed. The survival rates of these loading protocols should be analyzed.

Strengths and Weaknesses of the Systematic Review:

The authors used accepted methods to conduct the systematic review of the literature (Quorum statement). The strengths were: 1) the authors defined the clinical question using the PICO format; 2) the authors clearly defined the loading protocols to reduce ambiguity of the study results; 3) the authors' were able to apply a meta-analysis. Limitations were: 1) the authors claimed publication bias, but there was no indication that they looked for unpublished data and considered in the analysis; 2) although the authors claimed to assess the methodological quality of the studies using the Cochrane criteria and the Modified Jadad Scale, they did not provide supporting information; and 3) the authors did not state any language restriction nor did they provide a list of omitted studies.

Strengths and Weaknesses of the Evidence:

The weaknesses were: 1) the numbers of both the included studies and subjects were small; and early and immediate loading studies used different attachment systems.

Implications for Dental Practice:

The current systematic review provided results with limited evidence based on its high methodological quality mainly due to a limited number of original studies. All studies in this review included immediate loading groups that used a bar design on three or four implants. Therefore, the literature is lacking in clinical trials on early/immediate loading implants that use an unsplinted stud attachment system. It also can be argued that the conventional loading protocol remains the preferred design, based on their proven long-term results.

Critical Summary Publication Date:


These summaries are not intended to, and do not, express, imply, or summarize standards of care, but rather provide a concise reference for dentists to aid in understanding and applying evidence from the referenced systematic review in making clinically sound decisions as guided by their clinical judgment and by patient needs. American Dental Association © 2019