The patient was a 75-year-old male who underwent surgical resection due to left maxillary gingival carcinoma in 1990. A maxillary defect from the right central incisor tooth to the left second molar tooth and which extended to the soft palate was observed （HS classification: H6S1DXT4）. In 2008, the patient received a split type hollow obturator prosthesis with a magnetic attachment. In 2012, the patient re-visited this facility with the chief complaints of masticatory disorder, poor denture retention and instability, and requested a new maxillary prosthesis without a magnetic attachment. Therefore, improvement in denture retention and stability was attempted by modifying the hollow obturator in a new maxillary prosthesis. As a result, we devised a maxillary prosthesis with a cap mechanism where the interior can be washed. After insertion of the new maxillary prosthesis and dentures, a more hygienic state, satisfactory stability, and improved masticatory function were obtained with minimal adjustment.
