Stability of provisional materials in the immediate restoration of the edentulous maxilla: A retrospective Study

To compare the fracture incidence of conventionally vs. CAD/CAM fabricated provisional materials for immediately loaded, implant-supported fixed full-arch restorations in the maxilla, and to assess the relationship between provisional prosthesis fracture and implant failure.

In this retrospective cohort study, 114 patients were treated from 2005 to 2023 for immediate full-arch rehabilitation with ≥ four implants (557 implants). Provisional restorations were fabricated using glass fiber-reinforced acrylic or CAD/CAM with either high-impact polymer composite (HIPC), or graphene-reinforced resin (Graphenano, GN). Fisher's exact test was calculated for material type, prosthesis fractures, and implant failures (OR with 95% CIs). Time to fracture was compared with the Wilcoxon rank-sum test at p < 0.05.

During the provisional phase, 30 of 557 implants failed (94.61% survival rate). 24 prostheses fractured: 19.4% GF, 8.0% GN, 47.1% HIPC. Fracture was linked to implant failure (p < 0.05; OR = 7.01). Failure rates didn't differ significantly across materials (p = 0.07), but HIPC had higher fracture and failure rates than GF (p < 0.05) and higher fracture rates than GN (p < 0.05). Time to fracture was similar across groups (p > 0.05).

During implant healing, complete fracture of the provisional restoration was strongly linked to implant failure. Fracture rates varied, with the lowest for GN and the highest for HIPC. Retrospective design and confounding factors limit causality among fracture, material, and failure. Monitoring prosthesis integrity and material choice are crucial during immediate full-arch maxillary implant loading. Further prospective studies are needed.