Tooth wear has been studied in a dentally attending population, aged 46-85 years. The level of tooth wear was recorded for 100 persons using the tooth wear index of Smith and Knight. Aetiology was assessed using a history/questionnaire/examination. Erosion/attrition were postulated in 98 persons while abrasion was present in 82. All demonstrated some tooth wear and in 6.93% of 7,822 surfaces this was defined as pathological according to the threshold levels associated with the index. 84 persons had pathological wear on some surfaces but this was predominately cervical, only 12 persons showing pathological wear on the occlusal/incisal surfaces. Occlusal contact area was measured using imprints in soft opaque wax, transmitted light and a charge-coupled linear scanning array. The array is moved at 90 degrees to its axis by a linear translator to produce an image consisting of 1,600 lines, each of 2,048 pixels. This image is converted to hard copy using a DEC DDP 11/23 computer which will also give area measurements. Occlusal contact area ranged from 3.16 to 194.40 sq mm with a mean of 59.23 sq mm. Tooth wear is a significant clinical problem in this population. Wear on the occlusal/incisal surfaces is more common in older age groups and in males but could not be related to occlusal contact area or denture status by the methods used.