2.1 Study design
This is a methodological study for the validation of a search strategy to identify randomized clinical trials related to periodontitis on MEDLINE /PubMed.
2.2 Procedures for identification of the gold-standard set and the retrieved articles using the search strategy under evaluation
Stage 1 – Application of the Cochrane Collaboration’s methodological filter
Initially, the methodological filter was applied to identify randomized clinical trials, which was validated by the Cochrane Collaboration (Cochrane Highly Sensitive Search Strategy – HSSS) and has high sensitivity and precision for MEDLINE /PubMed , as follows:
#1 randomized controlled trial[Publication Type]
#2 controlled clinical trial[Publication Type]
#3 randomized [Title/Abstract]
#5 clinical trials as topic[MeSH Terms]
#8 #1 OR #2 OR #3 OR #4 OR #5 OR #6 OR #7
#9 animals [mh] NOT humans [mh]
#10 #8 NOT #9
A chronological filter was also used from January 01 to March 31, 2018.
Stage 2 – Application of the eligibility criteria
Among the articles retrieved concerning to randomized clinical trials, those related only to periodontitis were identified. In addition, exclusion criteria comprised of studies involving animal models and reviews of randomized clinical trials. This stage of reading titles and abstracts was performed by two authors (SSC and AOL) and confirmed by a more experienced periodontist (ISGF), in case of disagreement. When necessary, full-text versions were evaluated.
Thus, after performing the above stages, a set of references that composed the gold-standard articles was selected: randomized clinical trials, related to periodontitis.
Stage 3 – Definition of the search statement related to periodontitis
The search statement for identifying the condition of interest (periodontitis) was developed using the tool "advanced search" in MEDLINE/PubMed, as follows: 1) controlled vocabulary terms related to periodontitis were identified; 2) a periodontist and general dentist (ISGF and SSC) identified the main keywords and their derivations; 3) the retrieved articles were carefully analyzed, and the terms that were associated with studies not related to periodontitis were discarded, for example the term "gingivitis"; and 4) the procedure was repeated until the strategy was considered adequate, using the Peer Review of Electronic Search Strategies (PRESS, Supplemental File- Appendix A) checklist with the assistance of an experienced librarian (VSSS).
Finally, the following search statement for identifying periodontitis was developed:
#1 “Periodontitis” [Title/Abstract]
#2 “Periodontitis” [MeSH Terms]
#3 “Disease, Periodontal” [Title/Abstract]
#4 “Disease, Periodontal” [MeSH Terms]
#5 “Diseases, Periodontal” [Title/Abstract]
#6 “Diseases, Periodontal” [MeSH Terms]
#7 “Periodontal Disease” [Title/Abstract]
#8 “Periodontal Disease” [MeSH Terms]
#9 “Parodontosis” [Title/Abstract]
#10 “Parodontosis” [MeSH Terms]
#11 “Parodontoses” [Title/Abstract]
#12 “Parodontoses” [MeSH Terms]
#13 “Pyorrhea Alveolaris” [Title/Abstract]
#14 “Pyorrhea Alveolaris” [MeSH Terms]
#15 #1 OR #2 OR #3 OR #4 OR #5 OR #6 OR #7 OR #8 OR #9 OR #10 OR #11 OR #12 OR #13 OR #14
Stage 4 – Application of the search strategy under evaluation
Stage 4 comprised the combination of the search statement developed (Stage 3) with the abovementioned methodological filter (Stage 1) and subsequent application in MEDLINE/PubMed for the retrieval of randomized clinical trials related to periodontitis, defined as the search strategy under evaluation.
2.3 Data analysis procedures
The proposed search strategy was evaluated by analyzing the extent to which it retrieved the studies in the gold-standard articles set, and the sensitivity, specificity, and precision of this strategy were calculated according to the following formulas:
The 95% confidence intervals (95%CI) of the strategy performance values were calculated for each estimated measurement.