To cord or not to cord? That is still a question

Data sourcesA broad computerised search with similar key terms was performed in different databases that included: Ovid Medline, Thomson's ISI Web of Science, PubMed, Science Direct, EMBASE and the Cochrane Library. Grey literature, dissertations, abstracts and theses were searched too. Reference lists of the selected articles were hand-searched.Study selectionThe inclusion criteria included in vivo randomised clinical trials and quasi-randomised clinical trials using gingival retraction techniques with and without cord. Studies were included if they examined the primary outcome from the review: efficiency of haemostasis control, the amount of gingival displacement and the influence of the techniques on gingival/periodontal health. Secondary outcomes accepted for the review included subjective factors reported by the patient such as pain, sensitivity, unpleasant taste and discomfort and operator's experience with both techniques. Non-English papers, clinical reports, animals studies or in vitro studies were excluded.Data extraction and synthesisTwo authors independently searched and screened the articles. Disagreements were resolved by discussion. A third reviewer participated in the eligibility of the studies. The risk of bias was assessed using the Cochrane Collaboration tool. Due to the heterogeneity of measurement variables across the studies and the differences among the studies, a meta-analysis was not performed. A narrative assessment was performed for the outcomes: moisture/bleeding control, gingival displacement, gingival/periodontal health and the subjective outcomes.ResultsFrom the initial search that retrieved 1,342 articles, 19 potential relevant full-text articles were considered for the review. Seven studies were selected for the systematic review. Four randomised clinical trials were included. Sample size ranged from eight to 252 participants per study. Five studies were conducted on patients requiring any indirect fixed restorations on prepared teeth. Two studies were done on unprepared teeth. In all studies, participants were in good health, had a healthy gingival condition and a sound periodontal status.ConclusionsBoth techniques are reliable in achieving gingival retraction. The review supports the observation that gingival retraction paste can more effectively help to achieve a dry field and at the same time be less injurious to soft tissues, however its ability to displace gingival tissues, compared to retraction cord, was compromising. Rather than considering the cost of material or the individual preference of the operator, choosing the right technique to maximise clinical efficiency should be based on scientific evidence. It seems that impregnated gingival cords are more effective on thick gingival tissue whereas paste is more effective when minimal retraction is required for haemostasis control, preservation of the gingiva and less tissue displacement.