This paper tests whether the scale-dependent effective dimensionality model introduced in A Scale-Dependent Dimensionality Model of Solar Structure also produces measurable consequences in white dwarf stars. Using the Sun as the sole calibration point, we re-express the dimensional opening fraction as a density-dependent function and integrate modified n=1.5 polytropic structure equations. The resulting mass-radius relations show consistent, percent-level deviations from standard 3D predictions (ΔR/R ≈ 0.3–0.7% for α=0.05–0.15), while the effective spatial dimension gradually compresses from 3.0 toward ≈2.90 at high densities. The Chandrasekhar mass shifts upward by ~0.1–0.8%, providing an additional, independent observational lever. All model inputs are fixed by the solar calibration; no new parameters are tuned. This establishes white dwarfs as a second astrophysical laboratory for a unified, density-driven dimensionality law. Python code and figure scripts are included.Version 2Originally developed under the working name Recursive Dimensionality Theory, the framework has since converged on a radially driven, density-dependent modification of effective spatial dimensionality in stellar interiors, motivating the present name Radial Dimensionality Theory.