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- Volume 6, Issue 1, 2013
Journal of Minimum Intervention in Dentistry - Volume 6, Issue 1, 2013
Volume 6, Issue 1, 2013
SYSTEM Research note on: the association of lack of adequate allocation concealment with effect-size overestimationAuthor Steffen MickenautschSource: Journal of Minimum Intervention in Dentistry 6, pp 1 –14 (2013)More Less
Objective :To test the null hypothesis that clinical dental trials with adequate random sequence generation together with adequate allocation concealment do not differ in their effect size from trials lacking adequate concealment.
Study design and setting : The oral health section of the Cochrane database was searched online until 20 July 2011. All listed entries, except reviews in protocol stage and duplications, were included. Included systematic reviews were accepted for data extraction if they included bias assessment for random sequence generation and allocation concealment, as well as an analysis report of dichotomous data. From the accepted systematic reviews, datasets including number of observed events and total number of evaluated units for test- and control group; assessment results for selection bias concerning random sequence generation and allocation concealment were extracted. The extracted datasets were statistically analysed.
Results : A 28% effect size overestimation in association with the lack of adequate allocation concealment in selected dental randomised control trials was established and the null hypothesis was rejected.
Conclusion : Adequate random sequence allocation without adequate concealment of such allocation appears to be insufficient to prevent exaggeration of results due to selection bias in clinical dental trials.
Source: Journal of Minimum Intervention in Dentistry 6, pp 15 –29 (2013)More Less
Background : Systematic reviews aim to answer clearly formulated questions by using systematic and explicit methods for identifying, selecting, and critically appraising relevant research. However, as research progresses, the content of a systematic review may become obsolete. The modified Ottawa method was developed in order to identify qualitative and quantitative signals indicating the need to update a systematic review. The aim of this study was to investigate how well signals identified by the modified Ottawa method correspond with actual differences in key findings of an original systematic review and its subsequent update.
Method : The modified Ottawa method was applied to key findings of an original systematic review report concerning the longevity of tooth restorations placed according to the atraumatic restorative treatment (ART) approach in comparison to conventional restorative treatment using amalgam as gold standard.
Results : One qualitative and one quantitative signal were identified which corresponded well with the comparison results of the systematic review update and its predecessor.
Conclusions : Signals identified by the modified Ottawa method corresponded with actual differences in key findings (or lack thereof) of an original systematic review and its subsequent update. These results suggest that the modified Ottawa method is a useful tool in identifying update needs of original systematic reviews. However, as this conclusion is derived from the investigation of only one systematic review, further studies are needed in order to confirm the applicability for systematic reviews in general.
Source: Journal of Minimum Intervention in Dentistry 6, pp 30 –37 (2013)More Less
Review question : The objective of this quantitative systematic review is to appraise the current clinical literature for evidence whether loss of complete sealant retention is directly associated with caries occurrence on formerly sealed teeth and to apply the appraised evidence as test for the null-hypothesis that the retention/caries ratio between different types of sealant materials is not statistically significant.
Systematic literature search : The following electronic databases will be searched by two reviewers (SM and VY), independently: PubMed/Medline, Directory of Open Access Journals (DOAJ); IndMed and Scielo using Systematic reviews, if found of importance to the topic, will be checked for suitable trials.
Search term development : The string of search terms: "fiss* AND seal*" will be used for database search.
Article selection criteria : Clinical study reporting on the retention and caries occurrence of resin and/or glass-ionomer cement (GIC) fissure sealed permanent molar teeth (no distinction will be made between different types of resin-based sealants or conventional and resin-modified GIC); Minimum 24-month follow-up period.
Data extraction : Besides general trial information the following data will be extracted: N = Number of evaluated sealed teeth; nR = Number of teeth without completely retained fissure sealants - loss of complete material retention, considered as the 'surrogate endpoint'; nC = Number of sealed teeth with carious lesion/cavities - considered as the 'clinical endpoint' - per type of sealant material (Resin/GIC) at the end of each follow-up period.
Data analysis and reporting : The principle outcome measure will be the ratio of Risk of loss of complete retention (RR= nR/N) to the Risk of caries occurrence on formally sealed teeth (RC= nC/N) per sealant type (RR/RC ratio). Simple linear regression analysis will be conducted in order to quantify the association between loss of complete retention and carious lesion/cavity development, separately for sealant type. Mann-Whitney U test will be used to test the null-hypothesis that the difference in the RR/RC ratio between the different types of sealant materials is not statistically significant. Risk of bias will be assessed. Sensitivity analysis will be conducted, in regard to any factor assumed to have confounding influence on the obtained results. The completed systematic review report will be submitted as manuscript to a peer-reviewed journal in English language.