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A cephalometric analysis of facial and pharyngeal structures in cleft and non-cleft palate children
force applied. The development of a periodontometer provides an adequate tool for an analysis of tooth mobility following the application of orthodontic f0
tW3.
The mobility of a tooth is measured with an intraorally attached dial indicator or periodontometcr. The labiolingual and linguolabial excursions of thr tooth crown are measured. With the periodontometer in place, standardized forces of known magnitude are applied to the crown of the tooth under investigation. Using a mechanical instrument called a “forcemeter,” the force is applied at a right angle to the long axis of the tooth. Standard forces of 100 and 500 grams are being routinely used in this study. This study is being r&ricted to the dentition of the maxillary arch and to the six anterior teeth of the mandible. The mobility of the different teeth is hcing measured at different st,ages of orthodontic procedures up to and including the removal of retention appliances. At the present time, the study is not sufficiently advanced to present final, definitive data. Preliminary findings indicate that near maximum mobility of teeth is attained within one and one-half hours after the placement of separation wires. Tn several instances where rapid treatment procedures, such as an ant,erior bite plane, were initiated, teeth were observed to increase in mobilit! and then to return to their initial degree of mobility. Of necessity, a longitudinal study of this type will require long periods of observation before completion. Individual cases will be followed until after the removal of retentive appliances.
A Cephalometric Analysis of Facial and Pharyngeal Structures in Cleft and Non-Cleft Palate Children: By Young Ho Kim, D.D.S., Eastman Dental Dispensary,
Rochester, n’cw York.
This study was focused on a comparison of the anatomic relationship of facial and pharyngeal structures in cleft palate and non-cleft palate children. Proportional relationships of bony element,s were specifically studied. Fortytwo children with surgically repaired clefts of the lip and/or palate and fortytwo non-cleft children were studied. Lateral cephalometric headplatcs were obtained and t,racecl for each child. Both cleft and non-cleft palate samples wcrc divided into three age groups-(l) 3 to 5 years of age, (2) 6 to 8 years of age, and (3) 9 to 11 years of age-in order to minimize differences resulting from growth. An analysis of maxillary length measurements (ANS to PNS) revealed that it was in this area that the sharpest deficiency was noted in the cleft palate sample, The mandibular body length as measured from gnathion to gonion showed no difference between cleft and non-cleft samples. For all three age groups, in the non-cleft sample, the mean proportional maxillary length in relation to mandibular lengt,h was found to be relatively constant. In older ago groups of the cleft palate sample the maxilla itself was not only shorter. but it was found also to become proportionately shorter in reference to a near normal increase in mandibular length. According to the analysis, both anterior and posterior heights of the maxilla in cleft palate cases sermcd to be affected by the deformity. However. the deficiency in the posterior height of the maxilla appeared to be greater relationship of the in most of the cleft palate samples. The proportionate posterior maxillary height to the anterior maxillary height was determined. Smaller mean percentage figures were found in the cleft palate groups when Within this sample the deficiency in compared to the non-cleft groups.
392
ABSTRACTS
ANI)
REVIEW’S
Am. .I. 0,
ttKdontics
May,
1958
ltlaxillary height sccmd to be reflected in the Icvel of the palatal plant in t’(‘liIindi,ate(l tha,t iu 82.:: per cclnt of the ~lo~l-(~l~t’t t,ion to basion. The a&y& cases the cxtcnsion of the palatal planer Ccl1 below the level of basion. In x1.5 per cent of the cleft l)alatc cases the clstonsion 01’ the palat,al plan(a fell :I~)ov(~ the level of basion.
A Method of M&king Flexible Rubber Molds for Accurate Multiple Reproduction of Plaster Casts: By Philip R. Joram, Helen T. Grogan, and Sa,muel Pruzansky, D.D.S., Department of Health, Education and Welfare, Public Health Service, National Institutes of Health Medical Arts Sectlon, and the National Institute of Dental Research, Bethesda, Maryland. This research was motivated by the desire to duplicate a collection of casts of infants wit,h cleft palates. These casts were characterized by extreme undercuts. (Conventional methods employed in reproducing dental casts were worthless in that they could not reproduce these undercuts, nor did they allow for Often the procedure of duplicamultiple duplication from the same negative. tion threatened to damage the original cast. By adapting certain techniques employed in t,he field of medical art, it was found that a new liquid rubber could be utilized to fabricate strong, flexible, elastic, and accurate rubber molds which could reproduce ever? undercut and irregular or complex shape without damage to the original cast. In addition, numerous duplicates could bc made from a single rubber mold wit.hout apparent diminution of the accuracy of’ the mold. By gross inspection and measurement, the duplicates poured from rubber molds properly supported by a mother mold were indistinguishable from the original casts. Therefore, a more detailed and analytical comparison was made A pa,ntobetween a selected number of original casts and their reproductions. graphic t,ype of comparator devised for measuring the mucosal surface contours of impressions, casts, and dentures was utilized in this analysis. (:omparative measurements of the contoured palatal surface of the original cast and its rcprodnctions revealed a dimensional difference that rarely cxceedccj 0.005 inch.
Muscle Growth and Function in Relation to Skeletal Morphology: 13~J. Il. Scott, Am. J. Phys. Anthropol. 15: 197-234,1957. The form of certain parts of the skeleton dcpcnds for its full dcrelopmtnt on the degree of activity of the attached muscles. C’omplcs skeletal structures, such as the cranium, facial skeleton, and pelvis, have ot,her factors also concerned in form determination, and considerable uncertainty exists regarding the role of muscle action in determining the morphology of these parts. Scott attempts here to construct a working hypothesis of the developmental and functional interrelationships which may exist between the neuromuscular and skeletal systems within an organism. Differentiation of striped muscle commences in the human embryo at about the seventh week and the typical struct,urc of the muscle fibers is reached by the twenty-second week. The developing muscle fibers obtain nerve connections soon after their first differentiation (eighth week), but the maturation of the motor end plates and the comrncncemcnt of normal functional activity do not occur until t,hc end of the seventh month and are not, complete in the limbs, especially in the foot and leg, until after birth.
tW3.
The mobility of a tooth is measured with an intraorally attached dial indicator or periodontometcr. The labiolingual and linguolabial excursions of thr tooth crown are measured. With the periodontometer in place, standardized forces of known magnitude are applied to the crown of the tooth under investigation. Using a mechanical instrument called a “forcemeter,” the force is applied at a right angle to the long axis of the tooth. Standard forces of 100 and 500 grams are being routinely used in this study. This study is being r&ricted to the dentition of the maxillary arch and to the six anterior teeth of the mandible. The mobility of the different teeth is hcing measured at different st,ages of orthodontic procedures up to and including the removal of retention appliances. At the present time, the study is not sufficiently advanced to present final, definitive data. Preliminary findings indicate that near maximum mobility of teeth is attained within one and one-half hours after the placement of separation wires. Tn several instances where rapid treatment procedures, such as an ant,erior bite plane, were initiated, teeth were observed to increase in mobilit! and then to return to their initial degree of mobility. Of necessity, a longitudinal study of this type will require long periods of observation before completion. Individual cases will be followed until after the removal of retentive appliances.
A Cephalometric Analysis of Facial and Pharyngeal Structures in Cleft and Non-Cleft Palate Children: By Young Ho Kim, D.D.S., Eastman Dental Dispensary,
Rochester, n’cw York.
This study was focused on a comparison of the anatomic relationship of facial and pharyngeal structures in cleft palate and non-cleft palate children. Proportional relationships of bony element,s were specifically studied. Fortytwo children with surgically repaired clefts of the lip and/or palate and fortytwo non-cleft children were studied. Lateral cephalometric headplatcs were obtained and t,racecl for each child. Both cleft and non-cleft palate samples wcrc divided into three age groups-(l) 3 to 5 years of age, (2) 6 to 8 years of age, and (3) 9 to 11 years of age-in order to minimize differences resulting from growth. An analysis of maxillary length measurements (ANS to PNS) revealed that it was in this area that the sharpest deficiency was noted in the cleft palate sample, The mandibular body length as measured from gnathion to gonion showed no difference between cleft and non-cleft samples. For all three age groups, in the non-cleft sample, the mean proportional maxillary length in relation to mandibular lengt,h was found to be relatively constant. In older ago groups of the cleft palate sample the maxilla itself was not only shorter. but it was found also to become proportionately shorter in reference to a near normal increase in mandibular length. According to the analysis, both anterior and posterior heights of the maxilla in cleft palate cases sermcd to be affected by the deformity. However. the deficiency in the posterior height of the maxilla appeared to be greater relationship of the in most of the cleft palate samples. The proportionate posterior maxillary height to the anterior maxillary height was determined. Smaller mean percentage figures were found in the cleft palate groups when Within this sample the deficiency in compared to the non-cleft groups.
392
ABSTRACTS
ANI)
REVIEW’S
Am. .I. 0,
ttKdontics
May,
1958
ltlaxillary height sccmd to be reflected in the Icvel of the palatal plant in t’(‘liIindi,ate(l tha,t iu 82.:: per cclnt of the ~lo~l-(~l~t’t t,ion to basion. The a&y& cases the cxtcnsion of the palatal planer Ccl1 below the level of basion. In x1.5 per cent of the cleft l)alatc cases the clstonsion 01’ the palat,al plan(a fell :I~)ov(~ the level of basion.
A Method of M&king Flexible Rubber Molds for Accurate Multiple Reproduction of Plaster Casts: By Philip R. Joram, Helen T. Grogan, and Sa,muel Pruzansky, D.D.S., Department of Health, Education and Welfare, Public Health Service, National Institutes of Health Medical Arts Sectlon, and the National Institute of Dental Research, Bethesda, Maryland. This research was motivated by the desire to duplicate a collection of casts of infants wit,h cleft palates. These casts were characterized by extreme undercuts. (Conventional methods employed in reproducing dental casts were worthless in that they could not reproduce these undercuts, nor did they allow for Often the procedure of duplicamultiple duplication from the same negative. tion threatened to damage the original cast. By adapting certain techniques employed in t,he field of medical art, it was found that a new liquid rubber could be utilized to fabricate strong, flexible, elastic, and accurate rubber molds which could reproduce ever? undercut and irregular or complex shape without damage to the original cast. In addition, numerous duplicates could bc made from a single rubber mold wit.hout apparent diminution of the accuracy of’ the mold. By gross inspection and measurement, the duplicates poured from rubber molds properly supported by a mother mold were indistinguishable from the original casts. Therefore, a more detailed and analytical comparison was made A pa,ntobetween a selected number of original casts and their reproductions. graphic t,ype of comparator devised for measuring the mucosal surface contours of impressions, casts, and dentures was utilized in this analysis. (:omparative measurements of the contoured palatal surface of the original cast and its rcprodnctions revealed a dimensional difference that rarely cxceedccj 0.005 inch.
Muscle Growth and Function in Relation to Skeletal Morphology: 13~J. Il. Scott, Am. J. Phys. Anthropol. 15: 197-234,1957. The form of certain parts of the skeleton dcpcnds for its full dcrelopmtnt on the degree of activity of the attached muscles. C’omplcs skeletal structures, such as the cranium, facial skeleton, and pelvis, have ot,her factors also concerned in form determination, and considerable uncertainty exists regarding the role of muscle action in determining the morphology of these parts. Scott attempts here to construct a working hypothesis of the developmental and functional interrelationships which may exist between the neuromuscular and skeletal systems within an organism. Differentiation of striped muscle commences in the human embryo at about the seventh week and the typical struct,urc of the muscle fibers is reached by the twenty-second week. The developing muscle fibers obtain nerve connections soon after their first differentiation (eighth week), but the maturation of the motor end plates and the comrncncemcnt of normal functional activity do not occur until t,hc end of the seventh month and are not, complete in the limbs, especially in the foot and leg, until after birth.