To improve the retention of an existing denture and allow it to be worn more comfortably, the denture may be supported by relining material. We can reline a worn prosthesis which, due to the resorption of the foundation or subsequent deformation of its base has lost its adaptation and swings when unilaterally pressured, besides a new denture that is not well adapted to the mucous membrane, caused by an error during its manufacture. We can also reline immediate prosthesis which after relining becomes permanent and prosthesis that had been repaired. Substrate materials can be divided into hard and soft materials. Hard materials are used to permanently support a larger denture surface. Soft materials are used for painful and sensitive mucous membranes, sharp ridges, bone irregularities and for patients who can not tolerate a hard denture base. Soft materials are divided into acrylate and silicone based materials. Silicone materials show better properties over time and can be used longer. A special type of soft materials are tissue conditioners that are used for short-term priming and are changed every 4-7 days. They will be used in cases of traumatized and inflamed mucous membranes. They may contain antibiotic and anti-inflammatory ingredients. The lining can be done directly in the dental office and indirectly in the laboratory where the dental technician is involved. It is important to have the patient checked and to observe when to replace old materials with new ones