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The facial skeleton in children from 7 to 11 years of age—a longitudinal roentgenocephalometric study
In the final chapier, on retention, stress is placed on the part played by the cuspal inclined plane in occlusion and how it affects the stability of the treated case. Sound techniques of properly timed equilibration are suggested as a basic means of retention, together with the use of the usual mechanical devices until growth and maturation of the face are completed. As a text on the Jarabak technique, the material is complete. It is technically and scientifically valid and is presented in a clear, understandable manner. Orthodontists who use the technique will find this volume to be a valuable reference. Others will find it interesting and informative, with material not usually found in similar texts. The photographs, line drawings, and other technical data are excellent, and the editing and printing are of high caliber. This volume, concerned with a single orthodontic technique, is a worth-while addition to the orthodontic library. Harry G. Barrer. The
Facial Skeleton in Children From Roentgenocephalometric Study
7 to 11 Years
of Age-A
longitudinal
By F. P. G. M. van der L&den. Doctoral dissertation, University of Groningen, The Netherlands, 1959 (written in the Dutch language, with English, German, and French su8mmaries). 157 pages. A group of seventy-two children (thirty-three boys and thirty-nine girls) was studied annually. From this material, the first observation and one obtained after approximately 4 years were utilized for determining growth changes in the face. At the first examination the youngest subject was 6 years 2 months of age and the oldest one was 7 years 11 months. Children with marked malocclusions were excluded. At the age of 11, “normal” occlusion was found in thirt,een boys and fifteen girls; the remainder of the children had Class I and Class II malocclusions. The sample was representative of different socioeconomic levels in the city of Groningen. A large (375 cm.) focus-midsagittal plane distance was used in the lateral head radiography, while the midsagittal plane-film distance was 12 cm. Photographs show the cephalostat designed by Professor K. 0. Bylstra. Errors resulting from the conventional tracing of radiographs and pricking of landmarks in the original records were compared from double determinations of twenty individuals. Findings favored the tracing p rocedure, but the differences between the two techniques were relatively small. Statistical descriptions of absolute measurements, both linear and angular, at the two age levels were presented, together with data concerning their increments in the 4 year interval and correlations of the changes in various facial angles. Although this dissertation is written in the Dutch language, the English summary and the tables, labeled in the internationally accepted jargon of cephalometrics, provide a wealth of information. The analysis of growth increments is an especially valuable part of this study.
r-ozume h7umber
50 6
IZeliews
and
abstracts
1
fi!)
No attention was paid to the differences in maturat,ion among the children Moreover, the bridging of a 4 year interval, in spite of annual observations, does not permit determination of the timing of growth changes or, for that matter, an assessment of differences in the timing of increments for various parts 01 the facial skeleton and mandible. One would look forward to future repol’ts ot this longitudinal investigation from the TTnivtarsity ot‘ Groningen, particularI> when it is extended over a wider age span, as encountered in orthodontic, practice. The author is to be commended for a significant contribution ro till, quantification of facial growth. C’oenraad F. A. Jloo~rwes.
A Serial
Investigation
of
Facial
and
Statural
Growth
in 7-
to
12-Year-Old
Children
By John Broman Pike. A thesis submitted to the faculty of the Craduutr, School of the University of Minnesota in partial fulfillment of the requi,rcments for the degree of Master of Science in Dentistry, June, 1961. Fourteen boys and eleven girls, 7 to 12 years of age, with a negative medica/ history, acceptable dental development, and no previous orthodontic treatment. were studied. Four annual lateral head roentgenograms and statural determinations were obtained for each child. From tracings of the lateral head roentgenograms, two anteroposterior and two vertical parameters located in the facial skeleton were measured to the nearest 0.5 mm. The dimensions selected were mandibular length, maxillary length, total anterior facial height, and ramIls height. Stature was measured to the nearest millimeter. The foundation for this investigation was an assumption of constancy in tlrc> rat,e of growth of observed dimensions. Statistical computation involved thcx theories of linear regression and correlation. The relationship bet,xeen t,htt rates of st,atural growth and the growth rates of the facial skeletal dimensions WIY determined. On the basis of variation in growth rates among individuals and devia,tions from a constant rate of growth due to technical error, the possihil-it>of a method of predicting statural and facial skeletal dimensions was discussrcl. No attempt was made t,o project the findings of this study into age groups other than those reported. The hypothesis of a constant growt,h rate was WIIsidered applicable only to this limited period of growth. Similarly, it was CIIIphasized t,hat the results of the investigat,ion applied only to those intlividwrls tvho met the criteria of case selection. Analysis of the observed data over the indicated time period led to thus following findings : 1. All individuals demonstrated a close approximation to const,ancy in the qowth rates of statural and facial skeletal dimensions studied. ‘1. ?;o significant sex difference could bc found for any of the dimensional changes considered. 3. A relatively high degree of individual variation existed in the sample.
Facial Skeleton in Children From Roentgenocephalometric Study
7 to 11 Years
of Age-A
longitudinal
By F. P. G. M. van der L&den. Doctoral dissertation, University of Groningen, The Netherlands, 1959 (written in the Dutch language, with English, German, and French su8mmaries). 157 pages. A group of seventy-two children (thirty-three boys and thirty-nine girls) was studied annually. From this material, the first observation and one obtained after approximately 4 years were utilized for determining growth changes in the face. At the first examination the youngest subject was 6 years 2 months of age and the oldest one was 7 years 11 months. Children with marked malocclusions were excluded. At the age of 11, “normal” occlusion was found in thirt,een boys and fifteen girls; the remainder of the children had Class I and Class II malocclusions. The sample was representative of different socioeconomic levels in the city of Groningen. A large (375 cm.) focus-midsagittal plane distance was used in the lateral head radiography, while the midsagittal plane-film distance was 12 cm. Photographs show the cephalostat designed by Professor K. 0. Bylstra. Errors resulting from the conventional tracing of radiographs and pricking of landmarks in the original records were compared from double determinations of twenty individuals. Findings favored the tracing p rocedure, but the differences between the two techniques were relatively small. Statistical descriptions of absolute measurements, both linear and angular, at the two age levels were presented, together with data concerning their increments in the 4 year interval and correlations of the changes in various facial angles. Although this dissertation is written in the Dutch language, the English summary and the tables, labeled in the internationally accepted jargon of cephalometrics, provide a wealth of information. The analysis of growth increments is an especially valuable part of this study.
r-ozume h7umber
50 6
IZeliews
and
abstracts
1
fi!)
No attention was paid to the differences in maturat,ion among the children Moreover, the bridging of a 4 year interval, in spite of annual observations, does not permit determination of the timing of growth changes or, for that matter, an assessment of differences in the timing of increments for various parts 01 the facial skeleton and mandible. One would look forward to future repol’ts ot this longitudinal investigation from the TTnivtarsity ot‘ Groningen, particularI> when it is extended over a wider age span, as encountered in orthodontic, practice. The author is to be commended for a significant contribution ro till, quantification of facial growth. C’oenraad F. A. Jloo~rwes.
A Serial
Investigation
of
Facial
and
Statural
Growth
in 7-
to
12-Year-Old
Children
By John Broman Pike. A thesis submitted to the faculty of the Craduutr, School of the University of Minnesota in partial fulfillment of the requi,rcments for the degree of Master of Science in Dentistry, June, 1961. Fourteen boys and eleven girls, 7 to 12 years of age, with a negative medica/ history, acceptable dental development, and no previous orthodontic treatment. were studied. Four annual lateral head roentgenograms and statural determinations were obtained for each child. From tracings of the lateral head roentgenograms, two anteroposterior and two vertical parameters located in the facial skeleton were measured to the nearest 0.5 mm. The dimensions selected were mandibular length, maxillary length, total anterior facial height, and ramIls height. Stature was measured to the nearest millimeter. The foundation for this investigation was an assumption of constancy in tlrc> rat,e of growth of observed dimensions. Statistical computation involved thcx theories of linear regression and correlation. The relationship bet,xeen t,htt rates of st,atural growth and the growth rates of the facial skeletal dimensions WIY determined. On the basis of variation in growth rates among individuals and devia,tions from a constant rate of growth due to technical error, the possihil-it>of a method of predicting statural and facial skeletal dimensions was discussrcl. No attempt was made t,o project the findings of this study into age groups other than those reported. The hypothesis of a constant growt,h rate was WIIsidered applicable only to this limited period of growth. Similarly, it was CIIIphasized t,hat the results of the investigat,ion applied only to those intlividwrls tvho met the criteria of case selection. Analysis of the observed data over the indicated time period led to thus following findings : 1. All individuals demonstrated a close approximation to const,ancy in the qowth rates of statural and facial skeletal dimensions studied. ‘1. ?;o significant sex difference could bc found for any of the dimensional changes considered. 3. A relatively high degree of individual variation existed in the sample.