BZY measurements and MCI widths on dry skulls with only 31% of 92 skulls demonstrating a 1:16 ratio and the majority (42%) a ratio of 1:15.13 The clinical applicability of measurements taken on dry skulls is questionable. Other authors verified this ratio,3,4 but concluded that the correlation was not of sufficient magnitude to justify the selection of prosthetic teeth based on the ratio.4 One author reported a sex difference with MCI:BZY 1:16 ratio only present in their female subjects.5 MCI height in relation to facial height is less investigated than width. Berry and House and Loop proposed a relationship of 1:20 and 1:16 respectively of MCI height to face height measured from the hairline to the lower edge of the symphysis.2,3 However, House and Loop found that only 15% of measured tooth height correlated with the height determined subjects’ by the 1:16 relationship with up to 2mm variation which was thought to be related to incisal wear. Kern found no relationship between tooth height and skull height (measured from bregma to menton) with a range between 1:18 and 1:21. However, he found a ‘significant’ percentage (81%) of skulls to have a ratio of 1:11 of tooth height to nasio-menton.13 Tooth height has also been compared to upper, middle and lower facial heights but with inaccurate correlations.7 dimensions of maxillary central incisors in the Caucasian population have been ‘Average’ defined as: Crown width: 8-9mm; Crown height: 10-11mm; Width-to-height ratio: 0.75:0.8.14 When comparing right and left MCI dimensions, there are inconsistencies in findings with some authors reporting discrepancies in horizontal15 and vertical measurements,16 and others finding no significant differences in mesio-distal diameters.17 Gender variations in anterior teeth dimensions have been reported for most ethnic groups, with men exhibiting larger anterior teeth than women, and black subjects tending to have larger teeth than white subjects,18–21 but with consistent width-to-height ratios.10,22 Few studies compare ethnic groups23 and others are limited by unequal distribution of sexes7 and poorly stated inclusion and exclusion
BZY measurements and MCI widths on dry skulls with only 31% of 92 skulls demonstrating a 1:16 ratio and the majority (42%) a ratio of 1:15.13 The clinical applicability of measurements taken on dry skulls is questionable. Other authors verified this ratio,3,4 but concluded that the correlation was not of sufficient magnitude to justify the selection of prosthetic teeth based on the ratio.4 One author reported a sex difference with MCI:BZY 1:16 ratio only present in their female subjects.5 MCI height in relation to facial height is less investigated than width. Berry and House and Loop proposed a relationship of 1:20 and 1:16 respectively of MCI height to face height measured from the hairline to the lower edge of the symphysis.2,3 However, House and Loop found that only 15% of measured subjects’ tooth height correlated with the height determined by the 1:16 relationship with up to 2mm variation which was thought to be related to incisal wear. Kern found no relationship between tooth height and skull height (measured from bregma to menton) with a range between 1:18 and 1:21. However, he found a ‘significant’ percentage (81%) of skulls to have a ratio of 1:11 of tooth height to nasio-menton.13 Tooth height has also been compared to upper, middle and lower facial heights but with inaccurate correlations.7 ‘Average’ dimensions of maxillary central incisors in the Caucasian population have been defined as: Crown width: 8-9mm; Crown height: 10-11mm; Width-to-height ratio: 0.75:0.8.14 When comparing right and left MCI dimensions, there are inconsistencies in findings with some authors reporting discrepancies in horizontal15 and vertical measurements,16 and others finding no significant differences in mesio-distal diameters.17 Gender variations in anterior teeth dimensions have been reported for most ethnic groups, with men exhibiting larger anterior teeth than women, and black subjects tending to have larger teeth than white subjects,18–21 but with consistent width-to-height ratios.10,22 Few studies compare ethnic groups23 and others are limited by unequal distribution of sexes7 and poorly stated inclusion and exclusion