Clinical Assessment of Flexible and Non-Metal Clasp Dentures: A Systematic Review

Background/Objectives: The present study aimed to evaluate the oral health and patient satisfaction of flexible and non-metal clasp dentures (NMCD) compared to removable partial dentures (RPD) using a systematic review. Methods: The PICOS framework of this review was as follows: Do rehabilitations involving flexible dentures or NMCD have a similar success rate to those using RPD? Thus, the PICOS approach involves the following topics: (P) Population/Problem: partial edentulous adult patients; (I) Intervention: patients rehabilitated with flexible dentures or NMCD; (C) Comparison: patients rehabilitated with standard RPD; (O) Outcome: clinical parameters such as oral health, masticatory function, and patient satisfaction; and (S) Study Type: clinical trials and observational studies (cohort, case–control, and cross-sectional). No language restrictions were applied to the studies. The search strategy consisted of the following keywords in different databases: ((flexible) OR (nonmetal) OR (non-metal) OR (thermoplastic)) AND (denture). Only clinical trials and observational studies (cohort, case–control, and cross-sectional studies) from the last 15 years were included, and no language restrictions were applied. Studies that did not describe the denture material were excluded. Results: Of the 2197 potentially relevant records, 14 studies were included in the present review. Two studies reported retrospective results, while twelve reported a prospective evaluation. Considering the thermoplastic materials, five studies evaluated polyester, five polyamides, three polyacetals, and only one study evaluated polyetheretherketone (PEEK). Flexible dentures and NMCD demonstrated similar periodontal status and bone levels on abutment teeth to RPD after up to 12 months. Flexible dentures exhibited a higher degree of redness of the mucosa after 12 months. One study showed a lower maximum bite force for flexible dentures compared to RPD. No study has performed a clinical evaluation of mastication and chewing ability. Conclusions: Despite increased short-term patient satisfaction for flexible dentures and NMCD, there is weak evidence to support a similar clinical performance of flexible dentures and NMCD to RPD.