Fiber-reinforced composite or zirconia in cantilever fixed dental prosthesis? 36-month follow-up clinical study? 36-month follow-up clinical study

OBJECTIVES: This clinical study evaluated the survival rate of different designs of single-retainer inlay-retained fixed dental prostheses (IR-FDPs) made from monolithic zirconia (Z) and fiber-reinforced composite (FRC).

METHODS: A total of 40 IR-FDPs (n=40) were placed for 32 female patients who presented with missing mandibular second premolar teeth. In the current study, the mandibular first molar was selected as a retainer for the cantilever IR-FDPs. The participants were randomly divided into two groups (n=20) according to the design: lingual coverage (LC) and occlusal coverage (OC). Each group was then divided according to the material used (n=10 Z and n=10 FRC). All restorations were bonded with adhesive resin cement and evaluated clinically and radiographically for 36 months following modified FDI (World Dental Federation) criteria. Statistical analysis was conducted using Monte Carlo and the Student (Cochran Q) tests.

RESULTS: All restorations showed non-significant differences (P>0.05) regarding the clinical behavior with satisfactory final aesthetic, functional, and biological results based on the criteria of modified FDI scores. Over a 36-month observation period, one restoration that belonged to group OC-Z fractured at the connector after 30 months and was replaced. Only one restoration in group LC-Z was debonded after 10 months and re-bonded, and one abutment in group LC-FRC was endodontically treated after 12 months.

CONCLUSIONS: Zirconia and fiber-reinforced composite cantilever IR-FDPs demonstrate high survival (97.5%) and success (96.6%) rates over 36 months, offering a minimally invasive solution for posterior tooth replacement with improved aesthetics and function.

CLINICAL SIGNIFICANCE: Lingual and occlusal coverage designs significantly enhance the strength and longevity of cantilever IR-FDPs while offering a reliable, minimally invasive solution with function, durability, and aesthetics. These designs effectively withstand occlusal forces when the cantilever pontic has a contact point.