Objective: To determine the effectiveness of dental health care services in facilitating recovery from quality of life decrements in symptom-specific subgroups with the most prevalent chronic infectious diseases (periodontal disease and dental caries), and a 'stained teeth' subgroup. Methods: Data were taken from the prospective longitudinal Florida Dental Care Study of 873 individuals 45+ years old. Logistic regression modeling quantified associations between recovery from oral health-related quality of life decrements ('recovery') and dental services. Results: Adjusting for age, race, gender, income, approach to dental care, and signs/symptoms, any dental visit (odds ratio, OR: 4.0; 95% confidence interval, CI: 2.3, 6.9), corrective treatment (OR: 3.8; 95% CI: 1.6, 8.7), denture visit (OR:4.8; 95% CI: 1.1, 21.9), or extraction (OR: 6.2; 95% CI: 2.2, 17.4) were positively associated with recovery. Upon conditioning the analyses on specific symptoms, point estimates increased substantially for most service types, and dental cleaning was associated with recovery for the stained teeth subgroup (OR: 10.9; 95% CI: 1.2, 99.4). Conclusion: Dental care was highly effective in treating quality of life decrements. Treatment effectiveness increased substantially when analyses were restricted to symptom-specific subgroups similar to selection criteria of randomized clinical trials (RCTs). Restricted cohort analyses can be applied to many other health outcomes for which RCTs are not feasible or ethical.