Width/length ratios of normal clinical crowns of the maxillary anterior dentition in man

Abstract

The purpose of this investigation was to analyze the clinical crown of the 3 tooth groups of the maxillary anterior sextant of the permanent dentition of normal subjects with respect to (i) width, length and the width/length ratios and (ii) determine if there is a correlation between tooth dimensions or tooth group ratios and subject height. Subjects (> or = 20 y.o.) were recruited for this study if (i) the free gingival margin on the facial surface of teeth in the maxillary sextant was positioned apical to the cervical bulge, (ii) there was no evidence of attachment loss; as determined by lack of a detectable CEJ and (iii) the marginal tissue was knife edged in form, firm in consistency and coral pink in color. Teeth were excluded if (i) there was evidence of gingival alteration, i.e., gingival overgrowth/hyperplasia, inflammation, altered passive eruption, attachment loss, gingival recession or history of periodontal surgery, or (ii) there was evidence or history of incisal edge/proximal tooth alteration as in, i.e., restorative intervention, traumatic injury or occlusal wear into dentin. At least 1 suitable tooth from each tooth group of the maxillary anterior dentition had to be present. A maxillary impression was taken and poured in yellow die stone. The widest mesial-distal portion and the longest apical-coronal portion of the test teeth were measured. Gender, ethnicity and subject height (SH) were recorded for each participant. Due to a limited ethnic diversity only data from the Caucasian group were analyzed. The mean coronal tooth width (mm) of males versus females was CI: 8.59 versus 8.06, LI: 6.59 versus 6.13 and CA: 7.64 versus 07.15. The mean coronal tooth length (mm) of males versus females was CI: 10.19 versus 9.39, LI: 8.70 versus 7.79 and CA: 10.06 versus 8.89. All width and length measures were significantly greater for males than for females. The mean coronal tooth width/length ratios for males versus females was CI: 0.85 versus 0.86, LI: 0.76 versus 0.79 and CA: 0.77 versus 0.81. A comparison between genders of the width/length ratios of the CI and LI were found not to differ, however the CA ratio for females was significantly greater than for males. A statistically significant difference was found to exist between the mean (cm) SH for males versus females: 181.2 versus 164.0. A positive correlation (p < or = 0.0001 to 0.0691) was found to exist between tooth group width/height ratios within genders. No significant correlation was found between any of the tooth dimensions or tooth group ratios and SH. The results of this study indicate that within male and female Caucasians, the mean width/length ratio of the maxillary 3 anterior tooth groups is 0.81. As well, within both genders there is a positive correlation between tooth group width/length ratios. The significance of these findings with respect to periodontal mucogingival plastic surgical procedures is discussed.

The influence of maxillary central incisor height-to-width ratio on perceived smile aesthetics

“…Central incisor width-to-height ratios of 0.76, 3 0.78 4 and 0.86 5 have been found in studies of clinical crowns of human teeth. The last figure is calculated from clinical crown measurements using dental casts and is therefore not comparable with the first two ratios which are calculated from anatomical crown measurements.…”

The size of anterior teeth in patients with gaps in the upper dental arch

“…Altogether 180 teeth were tested (60 teeth for each tooth group). The results were compared with the values indicated by Sterrett et al [21] who studied W/L ratio of maxillary front teeth. They made alginate impressions of maxillary arch and poured in yellow dental stone.…”

“…They made alginate impressions of maxillary arch and poured in yellow dental stone. On plaster models they measured the widest mesiodistal and the longest apicocoronal portion of test teeth using callipers (with 0.05 mm accuracy) [21]. The mean W/L ratios published by Sterrett et al [21] …”

Relationship between width and length ratios of upper anterior teeth in young Chilean population.

“…Subjects with gingival alteration or those who had undergone periodontal surgery 4 or had foreign ancestry of at least three previous generations were also excluded from the study. The size of the sample was established with the measurements of the width of the upper incisors proposed by Orozco-Varo 3 (8.6±0.5mm), postulating the hypothesis that the mean width of the central incisors presents a difference of ± 1mm.…”

“…The procedure was explained to the subjects who agreed to participate by signing an informed consent form. Upper dental arch models were made to record mesiodistal width and height of the six upper anterior teeth in millimeters based on the protocol designed by Sterret et al 4 Once plaster models were obtained, a previously calibrated researcher measured central incisor teeth, lateral incisors and canine teeth on the right side of the subject's mouth using the Mitutoyo® digital caliper (Japan, 0.01mm accuracy).…”