Dental Therapy Radiograph Prescribing Thresholds and Restorative Yield in Ugandan Health Centres: A Regression Discontinuity Analysis of Diagnostic Stewardship

Ugandan dental therapy practice delegates radiograph prescribing to mid-level clinicians working under severe resource constraints, yet the diagnostic thresholds that govern when a radiograph is ordered remain unstandardised and unexamined. the present analysis treats radiograph prescribing as a diagnostic stewardship problem and proposes a regression discontinuity design to estimate the restorative yield attributable to crossing a defined prescribing threshold. Using the DHS Program indicator 'Current users most recent supply or information from a government health center' (FP_SRCM_W_GHC) across 36 African countries and 150 country-survey observations from 1990 to 2025 (mean 25.261, SD 18.895, range 1.50 in Morocco to 51.89 in Zambia), the analysis establishes the empirical distribution against which Ugandan facility-level thresholds would be benchmarked. The proposed design exploits the discontinuity at a candidate threshold expressed as a count of pre-specified clinical indications, comparing restorative intervention rates just above and just below the cut-point. Diagnostic stewardship in dental therapy requires threshold transparency rather than radiograph rationing, and that regression discontinuity offers a credible identification strategy where randomisation is infeasible. The contribution is a transferable methodological framework for evaluating prescribing thresholds in mid-level dental practice, together with a demonstration that existing population-level indicators can anchor threshold calibration without substituting for facility-level estimation.