No abstract available.
Malocclusion*

No abstract available.
Malocclusion*

Variation in the facial pattern and effect of the rotational jaw growth on the facial proportion were studied in serial cephalometric radiographs of 40 Korean children (35 boys, 15 girls) ranging in age from 6 to 13 years. According to Y-axis (N-S-Gn) growth change during the 7 years of period, the subject who had exhibited "wave-like" manner of Y-axis growth change within +/- 2degrees was classified to the Parallelwise group and the subject who had exhibited Y-axis increase more than +/- 2degrees was classified to the Clockwise rotation group and the subject who had exhibited Y-axis decrease more than -2degrees was classified to the Counterlockwise rotation group. For the comparison of each group, a total of 22 morphologic variables were employed and the data were analyzed by means of computer morphometrics and statistical methods. On the basis of the finding of this study, the following trends were eatablished: 1. The Parallelwise group was 75%, the Clockwise rotation group was 12.5% and the Counterclockwise rotation group was 12.5%. 2. The growth pattern of cranial base was related to the rotation of mandible. 3. Maxillary prognathism was occured in the Counterclockwise rotation group and the rotation of palatal plane was occured in the Clockwise rotation group. 4. Mandibular prognathism was occured in the Parallelwise and the Counterclockwise rotation groups, especially in the Counterclockwise rotation group. 5. The degree of maxillo-mandibular divergency was constant in the Clockwise rotation group but decreased in the Counterclockwise rotation and the Parallelwise groups, especially in the Counterclockwise group. 6. There were no differences in the size of the anterior upper facial height (N-ANS) and the posterior lower facial height ((Go-Me)-PNS) but there were differences in the size of the anterior lower facial height (ANS-Me) and the posterior upper facial height ((S-N)-PNS) between each group. 7. The growth increment and the size of the facial gepth was not relater to the growth pattern of the face but the growth increment and the size of the facial height was related to the growth pattern of the face. 8. Proportional change due to the facial growth rotation was concentrated in the anterior lower face. 9. The most apparent difference between each group was happened in the size of the posterior cranial base (S-Ba) and the facial length (S-Gn).
Child ; Humans ; Jaw ; Mandible ; Prognathism ; Skull Base

The objective of this experiment is to observe structural differences in the orthodontic movement of vital (control group) and devitalized (experimental group) teeth in the mongrel dogs. The 5 utilized dogs in this experiment were approximately 1 year of age and their average weight was about 12Kg. Endodontic therapy was performed on the 2nd premolars in upper & lower jaws of each animal under the general anesthesia by intravascular injection of 25mg/Kg of pentobarbital sodium. The canals of the teeth were obturated by using gutta percha in conjunction with root canal sealer (AH26 Densply). One of the roots in the 2nd premolars was hemisected to make an extraction space for the devitalized teeth to be moved. The edgewise technique was employed for the movement of the teeth. Orthodontic models and intraoral roentgenograms were taken before and after orthodontic tooth movement. The open coil springs (.010 x .040) were used at interbraket space in order to provide equal forces (75gm) between the teeth in each arch wire. After 13 weeks of active orthodontic tooth movement, dogs were sacrified and the experimental results were examined through the intraoral radiography, microscopic examination and scanning electromicroscopic examination at the root surface. From the results of the study, the following conclusions may be drawn: 1. The root resorption and cemental deposition were observed within the pressure and tension site in both group. 2. The root resorbed lacunae were observed in the cementum and/or into the dentin in both group. 3. The prominent osteoblastic activities were observed on the alveolar margin in the tension site in both group. 4. A few of blood vessels were observed in the pressure site, but also lots of blood vessels were observed in the tension site especially in the periphery of the alveolar bone in both group. 5. In the pressure site, resorbed lacunae were formed with deep and narrow cavity in the control group; the shallow and wide cavity in the experimental group. 6. In the pressure site, the repaired cementum or cementoid tissue was lined on cementum in the experimental group, but not in the control group. 7. There was no significant difference between external root resorption of endodontically and vital teeth when both were subjected to orthodontic forces.
Anesthesia, General ; Animals ; Bicuspid ; Blood Vessels ; Dental Cementum ; Dental Pulp Cavity ; Dentin ; Dogs* ; Gutta-Percha ; Jaw ; Osteoblasts ; Pentobarbital ; Radiography ; Root Resorption* ; Tooth Movement* ; Tooth* ; Tooth, Nonvital

The primary objective of this study is to estimate of the mesiodistal crown diameters of the unerupted permanent successors derived from the mesiodistal crown diameters of the deciduous teeth in Korean population. The subjects were 54 indiciduals (twenty nine boys and twenty five girls) with normal occlusion aged 6 to 13 years. The mesiodistal crown diameters of the deciduous and the successional permanent teeth were measured from the longitudinal dental cast models using the shding calipers (Mitutoyo Co.) From the study, the results are as follows, 1. Sex differences of mesiodistal crown diameters were less in the deciduous teeth, but male were more than that of female in the successional permanent teeth. 2. The mesiodistal crown diameters of the deciduous central incisors, lateral incisors, canines were smaller than that of the successional permanent teeth and the deciduous 1st molars, and 2nd molars were more larger than that of the successional permanent teeth. 3. Size differences between sum of the mesiodistal crown diameters of central meisors and lateral meisors in the decidous teeth and the successional permanrnt teeth were 7.20 +/- 1.79 mm in upper, 5.38 +/- 1.64 mm in lower and that of canine, 1st molar and 2nd molar in the deciduous teeth and the successional permanent teeth were 0.56 +/- 1.19 mm in upper, 2.22 +/- 1.19 mm in lower. 4. In male, the correlation coefficients between the upper deciduous central incisor and the successional permanent tooth (r=0.57) and in female, the correlation coefficients between the upper deciduous 1st molar and the successional permanent tooth (r=0.67) appeared the highest. 5. The regression constants were determined to estimate the mesiodistal crown diameters of the unerupted successional permanent teeth.
Crowns* ; Female ; Humans ; Incisor ; Male ; Molar ; Sex Characteristics ; Tooth* ; Tooth, Deciduous

Rapid maxillary expansion is widely used for the correction of anteroposterior discrepancies, constriction of the maxillary arch, etc. This experiment was undertaken to examine the serial changes in the osteogenesis as well as the collagen fiber bundles in the intermaxillary suture during the rapid maxillary expansion treatment. Four young female dogs aged 6 to 8 months old and not showing menarche yet were used for the experiment. The maxillary impression of dogs were taken, expansion device cast and Hyrax screw soldered at the midline in the 1st premolar area. RME device was delivered to the dogs and the activation of 0.25mm per quarter-tum was done 2 times per day for 10 days until 5mm separation was made. Separation of the maxilla was confirmed by X ?ray. The animals were sacrificed on 0, 15, 30, 60 days from the finish of maxillary separation and preparations for light microscopy and surface electron microscopy were made. The sutures were cut into frontal serial sections for examination of the histological reactions. The following results were obtained and the conclusions made. 1. The edges of the two palatal plates bordering the midpalatal suture which at the beginning of the retention period were mainly composed of compact bone, underwent extensive resorption followed by new bone formation and gradually became spongy bone rich in bone marrow which in the 60 day retention animal became the compact bone with short intermaxillary suture space. During this transformation, newly formed trabecular bone tissues were added to the original margin. 2. Throughout the expansion period, the collagen fibers underwent successive changes such as stretching, loss of polarity, and finally fibrillogenesis. Towards the end of the expansion procedure, sharpey's fiber formation in newly formed bones were observed. 3. Bony spicules were found in the initial stage of retention on occlusal topographic X -rays, which later were confirmed to have ossified. 4. Judging from the histological changes occuring during the experimental expansion, excessive expansion will cause an excessive bleeding, and retard the remodeling of intermaxillary suture. According to the above results, the bone remodeling after rapid maxillary expansion was preceded by the migration of migratory cells into the intermaxillary suture area. The bone remodeling phenomena were on-going during the 2 months retention sample.
Animals ; Bicuspid ; Bone and Bones ; Bone Marrow ; Bone Remodeling ; Collagen ; Constriction ; Dogs* ; Female ; Hemorrhage ; Humans ; Hyraxes ; Infant ; Maxilla ; Menarche ; Microscopy ; Microscopy, Electron ; Osteogenesis ; Palatal Expansion Technique* ; Sutures* ; Young Adult*

The purpose of this study is to observe how the Class III intermaxillary elastics act upon the craniofacial structures of mixed dentition with anterior crossbites. The cephalometric head plates of 16 children treated only with Class III elastics (C III elastics group) and 23 children treated with Class III elastics and Reverse pull headgear simultaneously (C III elastics + RPHG group) were traced, digitized and statistically analyzed. The results were as follows. 1. Anterior displacement of maxilla was observed in both groups. 2. Simultaneous Class III elastics and reverse pull headgear group showed the counterclockwise rotation of maxilla, however Class III elastics group manifested no rotational change of maxilla. 3. Simultaneous Class III elastics and reverse pull headgear group showed the downward and backward rotation of mandible, however Class III elastics group manifested no rotational change of mandible. 4. Counterclockwise canting of occlusal plane, labial tipping of upper incisor and lingual tipping of lower incisor and mesial displacement of upper molar to pterygoid root vertical were observed in both groups.
Child ; Dental Occlusion ; Dentition, Mixed* ; Head ; Humans ; Incisor ; Malocclusion* ; Mandible ; Maxilla ; Molar ; Traction*

Orthodontic traction has been suggested as the treatment of choice for intrusive luxation injuries. Prior research has shown orthodontic forces to be ineffective in the presence of ankylosis or in cases with zero mobility following the injury. If orthodontic traction is to be effective, it must be initiated prior to the onset of ankylosis. The purpose of this study was to describe the effects of intrusive luxation at various times following the injury, and to determine the time of the onset of ankylosis, and to examine what effect immediate partial luxation has on the onset of ankylosis. Eight young mongrel dogs were utilized for this study. Intrusive luxation was produced with an axial impact using a gravity hammer and a specially designed holding device on 4 teeth (2 max. and 2 man. first premolars) in each dog. The teeth were intruded approximately 3-4mm in an axial direction. One maxillary and one mandibular premolars were partially luxated with the other two teeth being untouched. Pre and posttrauma tooth position was documented with plaster models and radiographs taken with an individualized X-ray jig. Dogs were sacrificed immediately following the injury and at 1,2,4,7,10,14 and 21 days respectively. Tetracycline was administered as a vital bone marker 24 hours before sacrifice. Block sections of the tooth and alveolus were prepared for decalcified and non decalcified histologic sections. The effects of traumatic intrusion were analyzed by means of model casts, radiographs, tetracycline bone marking and histologic preparations. The results obtained were as follows: 1. The animal sacrificed immediately following the injury displayed alveolar fractures, torn periodontal ligaments, and areas of direct tooth-bone contact. 2. The odontoblastic layer of the pulp was disorganized as early as 24 hours after the injury. 3. Bony remodeling was noted at 4 days along with active surface resorption. 4. Ankylosis was first seen 7 days after the injury. 5. Osteogenesis in the dentin (thick tetracycline bands) was observed 7 days after the injury. 6. There was no progressive root resorption and ankylosis where the periodontal ligament has been healed. 7. The Luxated group showed significantly more root resorption and ankylosis than the Non-luxated group with increased observation periods. The results suggest that ankylosis may occur within the first week following the injury, and hence orthodontic traction should be initiated as soon after the injury as possible.
Animals ; Ankylosis* ; Bicuspid ; Dentin ; Dogs ; Gravitation ; Odontoblasts ; Osteogenesis ; Periodontal Ligament ; Root Resorption ; Tetracycline ; Tooth ; Traction

Serial cehalometric roentgenorgams of 40 Korean children (25 males, 15 females) were employed to study the growth changes of the cranial bases. As a result of this study, the following conclusions can be made: 1. The mean size of the cranial bases in males was larger than the females, especially at the age of 13. 2. In both sexes, growth of the cranial bases was seen from 6 to 13 years of age and the growth of the posterior cranial base (S-Ba) was larger than the anterior cranial base(S-N). 3. Variation in the changes of the saddle angle (Ba-S-N) was exhibited with males showing a marked tendency toward a decrease in saddle angle size.
Child ; Female ; Humans ; Longitudinal Studies* ; Male ; Skull Base*

This study was designed to investigate the growth amount and rate of mandible by the measurements of mandibular lateral surface and the relationship of peak growth increments between mandible and body height. The sample consisted of twenty-five boys and fifteen girls between the ages of 6 and 13 The surface of mandible was measured from digitized roentgenocephalometric analysis (A 27 point mandibular model) The findings of this study can be summarized as follows 1. No significant difference was found between mandibular lateral surfaces of the both sexes at the ages studied. 2. The mean growth amount of mandibular lateral surface from 6 to 13 years of ages was 9.09cm2 in boys and 8.29cm2 in girls, and the mean growth rate was 46.07% in boys and 42.57% in girls 3. The prepubertal peak growth increment in mandible was found between the ages of 11-12 in girls and 12-13 in boys 4. The prepubertal peak growth increments of mandible occured one year later that of body height in boys and girls.
Body Height* ; Female ; Humans ; Longitudinal Studies* ; Mandible