Forensic pathology has shown us that the tissues of the teeth undergo structural changes throughout life. Less clear is whether sex can be determined from simply observing teeth. The current study analyzed 18 permanent teeth extracted from cadavers between the ages of 20 and 40 years, as well as 71 patient casts from individuals aged 18 through 52 years. After rinsing the teeth, measurements were taken of the bucco-lingual and Mesio-distal diameter using a caliper before the teeth were placed in a formaldehyde solution for 17 days. A correlation test was applied between sex and the distance between the Mesio-distal and bucco-lingual cervical crown measurements. Results indicate that male teeth are larger; this fact is attributed to genetic factors, environmental factors, pathological conditions, climatic conditions, and endocrinal effects. The procedure described here is useful in forensic dentistry to determine sex. Figures, references