The variables affecting speed of tooth movement are unquantified. In particular, the effects of stress and human biological variations are unknown. Therefore, our objectives in this study were to determine relationships between (1) stress and velocity of tooth translation (v(t)), and (2) interleukin-1 (IL-1) gene cluster polymorphisms, IL-1beta and IL-1 receptor antagonist (IL-1RA) in gingival crevicular fluid (GCF), and v(t). Ten subjects had their maxillary first premolars extracted and cheek wipe samples genotyped. In each subject, a maxillary canine received 26 kPa and the other received 13 or 52 kPa of stress. GCF samples and tooth movements were measured at 9 or 10 visits over 84 days. Mean v(t) for canines retracted by 13, 26, and 52 kPa were 0.054, 0.072, and 0.064 mm per day, respectively. Faster v(t) was shown from 26 kPa than 13 kPa (P = .015) and 52 kPa (P = .030), with higher IL-1beta/IL-1RA in GCF at experimental relative to control sites, and in subjects with homozygosity for allele 1 (A1,A1) compared with at least 1 copy of A2 (A2+) at IL-1RN(VNTR(86 bp)) (P = .032), and with A2+ compared with A1,A1 at IL-1B(+3954) (P = .051). Stress, IL-1beta/IL-1RA in GCF, and IL-1 gene cluster polymorphisms are related to v(t).