This study evaluated the effects of giving patients treatment-relevant choices, and the influence of provider-patient interpersonal behaviors, on patients' adjustment to and satisfaction with a protracted healthcare procedure. 102 patients receiving complete dentures were randomly assigned to a Decisional Control group, a No-Decisional Control group, or to a Treatment as Usual Control group. No main effects for the "control" manipulations were obtained, and interactions obtained between control conditions and patient dispositional differences in locus of control were not consistent with earlier findings. Dentists' and patients' interpersonal appraisals of each other, as measured by the Impact Message Inventory, were the most significant factors accounting for patient outcome differences. Consistent with previous research, the experience of oppressive interpersonal impacts both by patients (physician low friendliness) and dentists (patient low friendliness, high dominance, high hostility) were associated with poorer patient outcomes.