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Local effects of Decadron on growth and development of the mandibular condyle of the rat
longitudinal
Study
of Growth
of Maxillary
By Elisha Roscoe Richardson, partment
of
Orthodontics,
Width
Graduate
Chicngo,
College, Vnivcrsity
of
Illinois,
De-
Ill.
Downs has demonstrated that a plaster cast, placed tccbth down on a film and radiographed from above, will yield a clear picture of the dental arch as well as an outline of what has been called the apical base. The area of apical base lying forward of the permanent first molars has been held to x’c-. main unchanged after the sixth year. The material studied c*onsisted of plastet casts of forty persons taken at. eight years and at sixteen years of age. The rcliabilit,y of the method was tested on a sample of twenty-five IO-year-olcl children and a sample of 20-year-old adults. These were’ s-rayed from a point 23.5 inches above and perpendicular to an occlusal film placed between the: teeth. The resulting films were compared with films of casts made at the same sitting. It was found that somewhat greater allowance was necessary for soft. tissue in children than in adults. The areas of the apical base, of the alveolar arch, and of the dental arch were mcasurotl in squara millimeters with a planimeter. Findings revealed that (1) the apical base grew beyond the sixth year in the majority of cases and became the arc of a larger circle; (2) the size of thr apical base is not necessarily the dominant factor determining th(a size of the dental arch; (3) the oriented occlusal s-ray film is a, valuable adjunct to growth st,udies.
local
Effects of Decadron Condyle of the Rat
By Richard I,. Clardy, Memphis, Tenn.
on
Growth
University
and
of
Development
Tennessee,,
of
C'ollege
the
Mandibular
of Den,tisft-!y.
This study was devised to determine the inhibitory effect on growth of thv mandibular condyle of the rat when small dosages of Decadron were I*I’peatedly injected into the mandibular joint. Thirty rats, 40 days of age, from a colony originally of the Wistar strain. were divided into three groups of ten animals each. The first group of animals was given intraperitoneal injections of Dreadron for the purpose of determirling systemic effects upon growth and development of the mandibular joint. The right mandibular joints of the second group of animals were injected wit,h physiologic saline solution to determine whether the presence of an inet.! material would affect local condylar growth. The left joints of the saline injected animals served as controls. The right mandibular joints of the last group of animals were injected with Decadron. and the left joints of thta same animals served as a second set of controls. All animals were injected at, weekly intervals. At 2 week intervals, beginning 2 weeks after the first irtinjection. one animal from each of the three groups was killed, until all a,rli-
788
Reviezus and
abstracts
mals had been sacrificed. Blocks of tissues containing t,he mandibular condyle were trimmed to 1 cm. square, sectioned, stained with hcmatoxylin ant1 cosin. and examined microscopically. Physiologic saline solution injected directly into mandibular joints of the rat did not appear to interfere with normal condylar development. Growth and development of the mandibular condylc of the rat were not altered by multiple localized or systemic injections of 0.03 cc. of a 0.5 rng. per cubic centimeter concentration of Decadron in physiologic saline solution.
A Myometric
and Cephalometric
Appraisal
By John G. Gorman, Washington
of the Tongue
University,
St. Louis, NO.
This investigation was undertaken in an attempt to evaluate the role the tongue might play in determining the position and alignment of the mandibula,r incisors. A reliable method for electronic measurement of lingual forces and cephalometric measurement of tongue posture was established. A transducer containing a miniature strain gauge was used to rneasurc pressures on the lingual surface of the mandibular incisors. This technique was used to compare the swallowing pressures and tongue postures of twenty-five subjects selected at random. These variables were correlated with certain angular measurements of skeletal and dental relationships taken from lateral cephalometric headplates. The following conclusions were made on the basis of statistical evaluation of the data: (1) The position and alignment of the mandibular incisors are not related to swallowing pressures or to the postural height of the tongue. (2) The anteroposterior position of the rnandible is not related to swallowing pressures or to the postural height of the tongue. (3) The presence or absence of tongue contact with the mandibular incisors at rest position is not related to the position or alignment of the teeth. (4) The presence or absence of tongue contact with the mandibular incisors at rest position tends to be related to the anteroposterior position of the mandible. (5) Swallowing pressures tend to be smaller when there is contact of the t,ongue with the mandibular incisors at rest position.
Orthodontics
and Tooth
By Bartram
Mobility
H. Levenson,
Eastman
Dental
Dispensary,
Rochester,
N. Y.
The purpose of this study was to investigate the degree of tooth mobility at various stages of orthodontic treatment. The degree of mobility of the maxillary and mandibular anterior teeth and the first premolars was measured in both the labial and lingual directions by means of a, specially designed electronic mobilometer.
Study
of Growth
of Maxillary
By Elisha Roscoe Richardson, partment
of
Orthodontics,
Width
Graduate
Chicngo,
College, Vnivcrsity
of
Illinois,
De-
Ill.
Downs has demonstrated that a plaster cast, placed tccbth down on a film and radiographed from above, will yield a clear picture of the dental arch as well as an outline of what has been called the apical base. The area of apical base lying forward of the permanent first molars has been held to x’c-. main unchanged after the sixth year. The material studied c*onsisted of plastet casts of forty persons taken at. eight years and at sixteen years of age. The rcliabilit,y of the method was tested on a sample of twenty-five IO-year-olcl children and a sample of 20-year-old adults. These were’ s-rayed from a point 23.5 inches above and perpendicular to an occlusal film placed between the: teeth. The resulting films were compared with films of casts made at the same sitting. It was found that somewhat greater allowance was necessary for soft. tissue in children than in adults. The areas of the apical base, of the alveolar arch, and of the dental arch were mcasurotl in squara millimeters with a planimeter. Findings revealed that (1) the apical base grew beyond the sixth year in the majority of cases and became the arc of a larger circle; (2) the size of thr apical base is not necessarily the dominant factor determining th(a size of the dental arch; (3) the oriented occlusal s-ray film is a, valuable adjunct to growth st,udies.
local
Effects of Decadron Condyle of the Rat
By Richard I,. Clardy, Memphis, Tenn.
on
Growth
University
and
of
Development
Tennessee,,
of
C'ollege
the
Mandibular
of Den,tisft-!y.
This study was devised to determine the inhibitory effect on growth of thv mandibular condyle of the rat when small dosages of Decadron were I*I’peatedly injected into the mandibular joint. Thirty rats, 40 days of age, from a colony originally of the Wistar strain. were divided into three groups of ten animals each. The first group of animals was given intraperitoneal injections of Dreadron for the purpose of determirling systemic effects upon growth and development of the mandibular joint. The right mandibular joints of the second group of animals were injected wit,h physiologic saline solution to determine whether the presence of an inet.! material would affect local condylar growth. The left joints of the saline injected animals served as controls. The right mandibular joints of the last group of animals were injected with Decadron. and the left joints of thta same animals served as a second set of controls. All animals were injected at, weekly intervals. At 2 week intervals, beginning 2 weeks after the first irtinjection. one animal from each of the three groups was killed, until all a,rli-
788
Reviezus and
abstracts
mals had been sacrificed. Blocks of tissues containing t,he mandibular condyle were trimmed to 1 cm. square, sectioned, stained with hcmatoxylin ant1 cosin. and examined microscopically. Physiologic saline solution injected directly into mandibular joints of the rat did not appear to interfere with normal condylar development. Growth and development of the mandibular condylc of the rat were not altered by multiple localized or systemic injections of 0.03 cc. of a 0.5 rng. per cubic centimeter concentration of Decadron in physiologic saline solution.
A Myometric
and Cephalometric
Appraisal
By John G. Gorman, Washington
of the Tongue
University,
St. Louis, NO.
This investigation was undertaken in an attempt to evaluate the role the tongue might play in determining the position and alignment of the mandibula,r incisors. A reliable method for electronic measurement of lingual forces and cephalometric measurement of tongue posture was established. A transducer containing a miniature strain gauge was used to rneasurc pressures on the lingual surface of the mandibular incisors. This technique was used to compare the swallowing pressures and tongue postures of twenty-five subjects selected at random. These variables were correlated with certain angular measurements of skeletal and dental relationships taken from lateral cephalometric headplates. The following conclusions were made on the basis of statistical evaluation of the data: (1) The position and alignment of the mandibular incisors are not related to swallowing pressures or to the postural height of the tongue. (2) The anteroposterior position of the rnandible is not related to swallowing pressures or to the postural height of the tongue. (3) The presence or absence of tongue contact with the mandibular incisors at rest position is not related to the position or alignment of the teeth. (4) The presence or absence of tongue contact with the mandibular incisors at rest position tends to be related to the anteroposterior position of the mandible. (5) Swallowing pressures tend to be smaller when there is contact of the t,ongue with the mandibular incisors at rest position.
Orthodontics
and Tooth
By Bartram
Mobility
H. Levenson,
Eastman
Dental
Dispensary,
Rochester,
N. Y.
The purpose of this study was to investigate the degree of tooth mobility at various stages of orthodontic treatment. The degree of mobility of the maxillary and mandibular anterior teeth and the first premolars was measured in both the labial and lingual directions by means of a, specially designed electronic mobilometer.