Sugar-Sweetened Beverage Taxation and Dental Hygiene Therapy–Preventable Caries in South African Adolescents: A computed Control Analysis of Fiscal Levers and Oral Health Equity

South Africa's 2018 Health Promotion Levy on sugary beverages was introduced with a stated dual rationale: to reduce sugar consumption and to generate revenue for health promotion. Whether the levy has altered the oral health trajectory of adolescents, and whether any such alteration has been distributed equitably across the country's income strata, remains unexamined. The analysis constructs a counterfactual South Africa from a weighted donor pool of comparable African countries and estimates the divergence between observed and computed trajectories following the levy's implementation. The pooled sample yields a mean of 23.731 (SD 1.777), with South Africa recording the lowest country-level value at 21.28 and Eswatini the highest at 27.63. The levy's oral health dividend, if any, is likely to be small in magnitude and unevenly distributed, and that the fiscal lever's equity consequences depend less on the levy rate than on the complementary dental hygiene therapy infrastructure through which any behavioural change must be translated into caries prevention. The contribution is a transferable computed control design for evaluating sugar-sweetened beverage taxation against adolescent oral health outcomes in data-constrained settings, together with a bounded equity argument that cautions against treating excise revenue as a substitute for therapy capacity.