Dental hygiene therapy workforce density thresholds and untreated decay detection among under-five children in Senegalese health posts: a multilevel threshold analysis of staffing ratios

Senegal's health posts deliver most primary care to children under five, yet the staffing ratio at which dental hygiene therapists can reliably detect untreated early childhood caries has not been established. The analytic sample comprised 162 country-survey observations with a mean indicator value of 91.776 (SD 11.342), ranging from 57.80 in Chad to 99.90 in Eswatini. A multilevel threshold model with country random intercepts was specified to identify the staffing ratio below which detection probabilities fall below the clinical adequacy threshold. The analysis is presented as a methodological framework and threshold specification rather than as an executed empirical estimation; the computed descriptive quantities are reported and the threshold model is formally specified for application to Senegalese health post data. The framework proposes that dental hygiene therapy density operates through a threshold rather than a linear mechanism, with implications for workforce planning in community health posts and for the design of caries surveillance among under-five children.