Purpose: The aim of this study was to investigate missing teeth and prosthodontic replacements in an institutionalized elderly population in China, and to assess dental functionality before and after the prosthodontic replacements based on a hierarchical dental functional classification (HDFC) system. Materials and Methods: A sample of 512 participants (9% aged 60-69 years; 29% aged 70-79 years; 62% aged ≥ 80 years) living in eight nursing homes in Qingdao were categorized by the HDFC with and without tooth replacements. A functional dentition in the HDFC meets all the following criteria: ≥ 10 natural teeth in each jaw; a complete anterior region; 3 or 4 posterior occluding pairs (POPs) in the premolar regions; and ≥ 1 POP bilaterally in the molar region. Participants with tooth replacements were reclassified. The score for effectiveness of replacements were as follows: 4 for ≥ 10 teeth in each jaw; 3 for a complete anterior region; 2 for 3 or 4 POPs in premolar regions; and 1 for ≥ 1 molar POP bilaterally. Results: Twenty percent of the participants had functional dentitions, but 42% met none of the functional criteria. In the branch '≥ 10 teeth in each jaw' the mean number of teeth present was 26.3 ± 2.9, and the mean number of POPs was 6.2 ± 2.0. In the branch ' 10 teeth in each jaw,' there were 13.4 ± 5.5 teeth and 1.1 ± 1.5 POPs. Of the 384 participants with natural teeth in each jaw, 44% had no replacements and 56% had fixed dental prostheses (FDPs), partial removable dental prostheses (PRDPs), or both. FDPs usually replaced 1 or 2 teeth, and PRDPs 3 or more teeth. On the basis of natural teeth plus artificial teeth (214 participants with replacements), 46% had functional dentitions while 18% met none of the functional criteria. In the promoted participants, the mean number of teeth added by FDPs was 3.6 ± 2.5, and for PRDPs it was 11.9 ± 6.5. FDPs had a significantly higher mean promotion value per tooth added than PRDPs. Conclusion: Approximately half the tooth replacements effectively met all criteria for a functional dentition.