Statement of problem: One of the main problems posed by complete dentures is retention and stability. In order to solve this problem, dentists and the dental industry for a long time have attempted to improve denture adhesion by developing a range of ?glues? of highly varied composition and efficacy. Purpouse: The present in vivo clinical study evaluates whether the adhesives used to improve complete denture retention are truly effective and able to increase denture adhesion to the mucosa covering the edentulous alveolar ridge of the mandibular dentures. Material and Methods: An in vivo clinical study is made of 30 patients with complete mandibular dentures to evaluate the retention afforded by three commercial complete denture adhesives (Benfix®, Fittydent® and Supercorega®). A spring scale was used to measure retention strength (in grams). The purpose was to determine whether the use of complete denture adhesives is effective, and to establish which commercial brands offer the highest retention strengths. Results and Conclusion:The results obtained indicate that retention is enhanced by the use of such adhesives, and that Fittydent® offers the best retention performance, followed by Benfix® and Supercorega®. Clinical implications: the study of denture adhesives and his efficiency are necessary to improve the edentulous patient satisfaction. More in vivo investigations are necessary in dental literature