Age and gender-related differences in premolar and molar functional areas.

summary  The aim of the present study was to underline the difference in premolar–molar functional areas according to both age and gender in a human adult population. Premolar and molar series were marked manually on opposed casts with articulating paper and functional areas were evaluated by quantification of these markings. It was noticed that on average larger functional areas were displayed by the older group (19 individuals, mean age 71·2 years, minimum 68 years, maximum 73 years) in comparison with the younger one (24 individuals, mean age 27·4 years, minimum 22 years; maximum 33 years). It was also observed that the average total functional area (4 hemiarches) was larger in the male subgroup (n: 23; mean age 45; young adults, 14; old adults, 9) compared with the female one (n: 20; mean age 49; young adults, 10; old adults, 10). Nevertheless, this gender difference in premolar–molar functional areas was related to the individual occlusal areas. As a matter of fact, when the individual occlusal area was taken into account for each series in the form of a ratio (functional area/occlusal area), the values obtained were not different between both gender subgroups studied. When comparing premolar and molar functional ratios (functional area/occlusal area) between age groups, it appears that the values obtained were slightly higher for the premolar series (ratios for young and older adults, respectively: Premolar series: 23·6 ± 7·5%, 30 ± 6·5%; Molar series: 23·1 ± 6·8%, 27·3 ± 6·7%). This difference was interpreted in relation to the reference (occlusal area) chosen.