A clinically unresolved question in full-arch implant rehabilitation is whether early peri-implant bone adaptation is primarily a local (implant-level) phenomenon, a shared within-arch response, or a patient-level characteristic—information is unavailable from conventional mean-based outcome reporting. This prospective secondary analysis quantified the hierarchical distribution of peri-implant marginal bone level change (ΔMBL) in monolithic zirconia full-arch prostheses directly connected to multi-unit abutments during the first year of function. Unlike mean-based endpoints, this approach identifies whether early bone adaptation variability originates primarily at the implant, prosthetic-arch, or patient level. Of 308 implants placed in 40 completely edentulous patients rehabilitated with 49 prostheses, 2 implants failed before delivery of the definitive prosthesis and were excluded from radiographic analysis, leaving 306 implants available for multilevel analysis. Implant-level ΔMBL was analyzed using an unconditional three-level linear mixed-effects model. Implant survival was 99.2%, prosthetic survival was 100%, and mean ΔMBL at 12 months was 0.38 ± 0.27 mm. Variance partitioning showed that 60.8% of total variability occurred at the implant level, 28.4% occurred at the patient level, and 10.8% occurred at the prosthetic-arch level, providing a framework for identifying at which level of the restorative system future clinical interventions may have the greatest impact. Findings should be interpreted within the context of a secondary analysis with a 12-month follow-up and no explanatory covariates; longer-term comparative studies with explanatory multilevel designs are required to confirm and extend these observations.

Whether arch-specific anatomical configuration affects early peri-implant bone behavior in monolithic zirconia full-arch prostheses is unclear. This prospective cohort study evaluated 40 edentulous patients with 49 monolithic zirconia full-arch prostheses (25 maxillary, 24 mandibular; 308 implants). MBR and patient-reported outcomes were recorded at baseline and 12 months; mandibular morphology (U- vs. V-shaped) was classified on CBCT, and inter-implant distance and cantilever length were measured on CAD designs. Because 9 of 40 patients contributed both arches, the primary MBR comparison used a linear mixed-effects model; morphology and geometry associations were exploratory (ANOVA; Pearson correlation). Implant and prosthetic survival were 99.4% and 97.9%. Mean MBR was higher in the mandibular (0.86 ± 0.06 mm) than the maxillary arches (0.73 ± 0.02 mm); the mixed-effects model estimated this difference as β = 0.13 mm (95% CI: 0.10–0.16; p < 0.001). V-shaped mandibles (0.91 ± 0.04 mm) showed higher MBR than U-shaped mandibles (0.81 ± 0.04 mm; mean difference 0.10 mm; p < 0.001), and inter-implant distance correlated negatively with MBR in the mandible (r = −0.70, p < 0.001) but not in the maxilla (r = 0.01, p = 0.97). Patient-reported outcomes improved markedly in both arches; two minor chipping events occurred, both in V-shaped mandibles. Monolithic zirconia full-arch prostheses showed favorable short-term outcomes in both arches. Arch- and mandibular-morphology-related differences in early MBR were statistically robust and highly consistent in standardized effect size, although the absolute differences were numerically modest; these findings suggest an association between anatomical configuration and early bone remodeling under rigid, full-arch monolithic zirconia frameworks that warrants further confirmation.