Virginia B. Knott

Statistics on eruption of the permanent dentition from serial data for North American white children.

Abstract No Abstract Available. * From the Institute of Child Behavior and Development, University of Iowa, and supported in part by a research grant, D-217, from the National Institute for Dental Research, National Institutes of Health.

Relation of the nasal and subnasal components of facial height in childhood

The relation between two components of facial height is investigated over the childhood period from the age of 4 years to the age of 12 years. Longitudinal data are described and analyzed for nasal heightsubnasal height × 100. Age trends and individual differences of fifty-five children who had not received orthodontic treatment and seven children who had been subjected to “bite-opening” therapy are presented and discussed. Age trend findings for the childhood years are that (1) on the average, the nasal component of facial height increases in relation to the subnasal component and (2) for individuals, nasal height in percentage of subnasal height may remain practically constant from age to age, or it may increase as much as 15 percentage points. Individual differences in nasal height relative to subnasal height are distributed from a minimum of 65.0 per cent (at the age of 4 years) to a maximum of 91.6 per cent (at the age of 11 years). In the small group of children treated orthodontically, it is found that after “bite-opening” procedures are initiated, they produce a temporary increase in subnasal height and consequently a temporary decrease in the percentage relation of nasal height to subnasal height.

Change during childhood and youth in facial depths from integumental profile points to a line through bregma and sellion

Summary This investigation was designed to study several facial depths and two facial angles. The materials were roentgenograms taken in norma lateralis on boys and girls studied longitudinally. From a line drawn through two calvarial landmarks and on through the face, perpendicular distances were measured to integumental points designated nose root, pronasale, superior labial sulcus, labrale superius, labrale inferius, inferior labial sulcus, and chin prominence. The angles measured were formed by intersection of an inferior mandibular line with the bregma-sellion line and the nasion-sellion line. The subjects were North American white children with acceptable orthodontic occlusion. Twenty-five boys and twenty girls were studied from age 5 to age 14, and smaller samples were studied between the ages of 14 and 17 years. Selected findings and proposed clinical implications are as follows: 1. Means for each facial depth studied increase with age throughout childhood and adolescence. Conversely, means for the acute angle between the nasion-sellion and inferior mandibular lines decrease with age. 2. Means at age 14 are larger than corresponding means at age 5 by approximately 18 per cent for distance from the bregma-sellion line to pronasale, 15 to 16 per cent for distance from the bregma-sellion line to the chin prominence, and 12 to 13 per cent for distance from the bregma-sellion line to the nose root. These figures support the generalization that, during childhood and adolescence, depth to pronasale is increasing relative to other facial depths. 3. Means in boys are significantly larger than those in girls for five depth dimensions compared at 5, 8, 11, and 14 years of age. 4. The means for the acute angle between the nasion-sellion line and the inferior mandibular line show an 8 per cent decrease over the period between 5 years and 14 years. A negative change during this 9 year span is found for 90 per cent of the individual subjects. This finding indicates the need for developing clinical norm values that decrease with age for angles involving the anterior cranial base and the inferior mandibular line. 5. The average angle found between the nasion-sellion and inferior mandibular lines is found to be significantly larger for girls than for boys at the ages of 5, 8, and 11 years (by about 3 degrees). This finding points to the desirability of separating the sexes for construction of clinical norms in respect to angles involving the inferior mandibular line. 6. All facial depths increase in variability between ages 5 and 11 years for girls and between ages 5 and 14 years for boys. There is considerable difference in the extent to which comparable distributions overlap at different ages. The distributions at ages 5 and 14 show no overlapping for the facial depth to pronasale and practically complete overlapping for the facial angle between the nasion-sellion and inferior mandibular lines. 7. With respect to facial depths at the levels of pronasale, labrale superius, labrale inferius, and the chin prominence, moderately strong positive associations are found for size at age 5 and for size at age 14. Associations of this type become slightly higher as the age span under study is shortened. 8. No evidence is found to support the hypothesis that face depth at a childhood age and subsequent increase in face depth are positively related variables. For the four depths involving pronasale, the upper and lower lips, and the chin prominence, size at age 8 and at age 11 varied independently of change in size during succeeding periods of 6 and 3 years, respectively. These results require critical reconsideration of a prevalent clinical perspective regarding prediction of changes during childhood of points on the integumental profile. 9. Moderately high associations ( r s between 0.91 and 0.95) are obtained for (a) change between 5 and 14 years in face depths at the levels of the upper lip and lower lip, (b) change between 5 and 14 years in face depths at the levels of the lower lip and chin prominence, (c) face depths at age 14 years for the upper and lower lip levels, and (d) face depths at age 14 years for the lower lip and chin levels. A negative correlation ( r = −0.64) is found for the change in the obtuse angle between the bregma-sellion and inferior mandibular lines and for the change in facial depth at the level of the chin prominence. 10. Multivariate facial comparisons are presented for selected subjects. These portray variations within and between individuals in facial depths and angles at childhood ages and in changes of facial depths and angles with age.

Serial Data On Primary Incisor Root Resorption And Gingival Emergence Of Permanent Successors

Abstract No Abstract Available. This investigation was supported in part by General Research Support Grant 5-SO1-FR 05313-06, College of Dentistry, University of Iowa.