Aim: The objective of this study was to carry out an in vivo investigation of patients wearing dentures relined with soft materials, assuming their positive and negative alterations in time.

Materials and methods: A direct survey method was used to gather data from 23 patients included in this study (11 male and 12 female patients). Twenty-seven dentures were made (12 partial and 15 total dentures) 9 of which in chairside procedures, 11 - in a laboratory, and 7 were made using the direct-indirect method. Patients were included in regular follow-ups at one month and six months, and at one, two, and three years after dentures delivery. The study started in 2014 and continued till 2017. 
The materials we used in the study were quite appropriate to this type of investigation, following the proper clinical and laboratory protocols. The two most commonly used groups of relining materials on the dental market nowadays were tested.

Results and discussion: All participants completed questionnaires which included questions related to changes in retention and stability of the relined dentures, changes in color and softness, in bond strength, and inflammation. 
The majority of patients were satisfied with the new dentures, but they also reported some problems concerning the staining and hardness of some of the investigated materials.

Conclusion: There were no significant differences in the behavior of the different groups of materials at six months. After six months we observed decline in the bond strength of the vinyl-polysiloxane (VPS) materials, as well as increased staining and hardness in the poly-methyl-methacrylate (PMMA).