Occlusal wear in dental prostheses milled from a two-colored shell-geometry disk: A prospective clinical pilot study

Objectives: The study aims to evaluate occlusal changes in milled complete removable dental prostheses (CRDP) at 6 months (6m) and 12 months (12m) of follow-up. Methods: Edentulous patients aged 50 years or more received maxillary and mandibular CRDPs, fabricated by computer assisted design and by subtractive milling. The prosthetic teeth were either milled from a monolithic two-colored shell-geometry polymethyl methacrylate resin disk (MP) or milled from a tooth-colored multi-layer disk (OP) prior to bonding to the denture base. The occlusal surfaces were scanned at 2 weeks (BL) post-insertion and compared to the follow-up scans made at 6m and 12m with a software using a best-fit algorithm. An additional comparative analysis of multiple points on the buccal and lingual cusps of the posterior teeth was conducted. Outcome parameters were root mean square (RMS) accounting for all deviations and average negative deviations (-Avg) for loss of substance. Results: Twelve participants (age 73 ​± ​12.0 years, 8 men, 4 women) were included: six received CRDPs on the upper and lower arch and six received a maxillary CRDP opposing a mandibular implant overdenture. RMS increased significantly from 50.3 ​± ​20.92 ​μm ​at 6 months to 69.6 ​± ​25.25 ​μm ​at 12m (p ​= ​0.035). -Avg values also increased significantly in both the maxilla and mandible between 6m and 12m (p ​= ​0.008, p ​= ​0.017). An increase in -Avg was observed between MP (−61.07 ​± ​21.63 ​μm) and OP (−46.60 ​± ​14.14 ​μm) at 12m, however non statistically significant (p ​= ​0.093). Conclusions: These findings suggest a pattern of occlusal wear in milled CRDPs, emphasizing the importance of material strength and the need for continuous monitoring of patient function. Clinical implications: One-year wear patterns in milled prosthetic teeth highlight the importance of material selection, reinforcing the need for periodic evaluations for maintaining occlusal integrity.