Prostheses equipped with an obturator are commonly used for prosthetic rehabilitation of patients after maxillary resection. The function of this type of a prosthesis is to close the communication between the mouth and the nasal cavity, fill the postoperative space and replace lost dentition. In addition to restoring the chewing function, prostheses have a positive effect on swallowing and speech, and also improve facial aesthetics. Among many types and methods of fabricating obturators, a relatively new solution is to make one from thermoformable material. The material is shaped using a vacuum mold, in a technique similar to the one used to make tooth-whitening splints. This solution has many advantages, including reducing the weight of the prosthesis and the ease of keeping the restoration clean. However, the most common problems are related to the surface fracture of the thermoformable material and loss of retention between the denture and the obturator. The aim of the study is to present a method of a direct repair of a postoperative prosthesis equipped with a thermoformable obturator. The conversionmethod proposed in this paper allows maintaining the original shape of the obturator and restoring the full functionality of the prosthesis in one visit.