Process-based quality measures are generally intended to promote evidence-based practices that have been proven to improve outcomes. However, due to lack of standardized implementation of diagnostic codes in dentistry, assessing the association between process and oral health outcomes has been challenging. To estimate the association of adhering to dental quality measures with patient oral health outcomes. Using a target trial emulation, a causal inference framework, this retrospective cohort study estimated the difference in the risk of developing tooth decay between US children who adhered to process-based dental quality measures (receiving topical fluoride and sealant [treated groups]) and those who did not (control groups). Electronic health records of US children and adolescents aged 0 to 18 years from January 1, 2014, to December 31, 2020, were used. To emulate random treatment assignment based on baseline confounders, coarsened exact matching was used to produce covariate balance between the treated and control groups. A time-to-event regression model produced effect estimates, adjusting for time-varying covariates. Near-far matching was used to account for unmeasured confounders as a sensitivity analysis. Data were analyzed from May 1 to August 7, 2023. Adherence to dental quality measures. Incidence of tooth decay. Among 69 212 US children aged between 0 and 18 years (mean [SD] age, 10.2 [5.0] years; 49.5% male, 50.4% female, and 0.1% unknown or transgender), 1930 (2.8%) were Asian, 2038 (2.9%) were Black, 8667 (12.5%) were Hispanic, 33 632 (48.6%) were White, and 22 945 (33.2%) were multiracial, other, or missing racial and ethnic group identification. Relative to control individuals, treated individuals were more likely to be at elevated risk of caries (fluoride measure: 16 453 [76.5%] vs 15 236 [39.8%]; sealant measure: 2264 [54.6%] vs 997 [44.0%]) and have regular dental visits (fluoride measure: 21 498 [100%] vs 13 741 [35.9%]; sealant measure: 1623 [39.2%] vs 871 [38.4%]). Adherence to quality measures was associated with reduced risk of tooth decay with adjusted hazard ratios of 0.82 (95% CI, 0.78- 0.86) for fluoride and 0.86 (95% CI, 0.76-0.97) for sealant in the matched cohort. Benefits of adhering to quality measures were greater among children at elevated vs low risk and with public vs commercial insurance for both measures. In this cohort study, adhering to dental quality measures was associated with reduced risk of tooth decay, and benefits were greater among children at elevated risk and with public insurance. These findings provide insights in facilitating targeted application of quality measures or developing more tailored quality improvement initiatives.