No abstract available.
Malocclusion* ; Malocclusion, Angle Class I* ; Molar*

No abstract available.

No abstract available.
Animals ; Bone Resorption* ; Dinoprostone* ; Rats* ; Tooth Movement* ; Tooth*

During diagnostic process of the orthodontic patients, it is not unusual to find canine impaction. Generally, the chief complaint of the patients is crowding or antetior crossbite which is not related with canine impaction, but sometimes they complainted delayed eruption of the canine or deviation of the adjacent teeth caused by canine impaction. Orthodondists have to make the proper treatment plan according to final treatment goals. On the following cases, two patients were diagnosed as a malocclusion with canine impaction, and were treated by different accesses, one by extraction, and the other by non-extraction each.
Crowding ; Humans ; Malocclusion ; Tooth

The purpose of this study was to evaluate self perception of occlusal status and recognition for ortho?dontic treatment as well as the prevalence of orthodontic treatment need objectively and subjectively. 3979 (male 2107, female 1872) school students of age 7~18 were analyzed by questionnaire and clinical examination and the results were as follows. 1. Perception of occlusal status on one's own was more generous than that of orthodontist's and it was affected by the factors such as age, patterns of malocclusion. 2. Recognition of subjective need for orthodontic treatment was more generous than that of objective need for the treatment, and factors such as age and sex of patient, parents' age and rate of education, income, occupation, classification of malocclusion and regional discrepancy were influenced. 3. Negative aspect of orthodontic treatment was influenced by the environmental factors. 4. A survey of want for orthodontic treatment showed one's alteration in recognition of the occlusal status with age and esthetic component was much more emphasized than functional component. 5. The multivariate discriminanat analysis for orthodontic treatment group showed that mother's rate of education, classification of malocclusion, demographic characteristics were critical in the determination of treatment group. 6. Test of inter-examiner reliability showed moderate coincidence.
Adolescent* ; Classification ; Education ; Female ; Humans ; Malocclusion* ; Occupations ; Prevalence ; Surveys and Questionnaires ; Self Concept

The purpose of this study was to analyze the growth and development of tooth germ and dental arch related to the bone growth during the fetal period. From 70 maxillae and 61 mandibles of the fetus aged 5, 6, 7, 8, 9 and 10 months, X-ray films were taken and measured. The results were as follows; 1. There was remarkable bone growth in the anterior and posterior area of palatum osseum, that were the interior portion of both deciduous canines anteriorly and the intero-posterior portion of both deciduous second molars posteriorly, where there was active bone growth and radiate formation of bony trabecylae was found. 2. The Growth of anterior tooth germ was greater than that of posterior germ, so anterior tooth germs were crowded. Especially in maxilla, the tooth germa of deciduous lateral incisors were located inside of dental arch and the tooth gerka of decoduous canines were located outside of dental arch. 3. Crowding amount increased with the fetal age because the growth of tooth germs was grdater than that of jow bone. 4. In the growth of upper dental arch, the increase of width was greater than that of length. 5. There was proportional relationship beween the arce of Palatal Trapezoid and the fetal age.
Bone Development ; Crowding ; Dental Arch* ; Fetus* ; Gestational Age ; Growth and Development* ; Humans* ; Incisor ; Mandible ; Maxilla ; Molar ; Tooth Germ* ; Tooth* ; X-Ray Film

This study was designed to investigate the reciprocal movement which was derived form application of active torque in ideal arch wire by computer-aided three-dimensional finite element analysis of maxillary teeth and surrounding periodontal ligament composed of 2617 elements and 3725 nodes. Ideal arch wire model was also made using the beam elements and the contact between the wire and the bracket slot was made using the gap element. In this study non-linear elastic behaviors of contact between the wire and the bracket slot were considered on. We put the active torque between the lateral and central incisor and between the second premolar and the first molar with/without cinch-back. The results were expressed by quantitative and visible ways. The findings of this study were as follows: 1. Reciprocal actions to active torque were complex system consisting of a combination of counter-torque, bucco-lingual linear displacement and tipping, rotation of the teeth, occluso-gingival linear displacement. 2. When active anterior crown labial torque was applied, crown labial tippings of the lateral were the greatest, and those of the central incisor was the next. Crown lingual tippings of the canine and the first premolar, mesial rotations and extrusion of the lateral and distal rotations and intrusion of the canine occurred. When anterior torque with the cinch-back was applied, amount of crown labial tippings of the lateral and central incisor were reduced. Amount of crown lingual tipping of the canine and the first premolar were increased. Mesial tippings and mesial rotations of the second molar occurred. 3. When active posterior crown lingual torque was applied, crown lingual tippings of the first molar were the greatest, and crown labial tippings of the second premolar and the first premolar were the next, the crown lingual tipping of the second molar were a little. Mesial rotations of the second premolar occurred but those of the first premolar didn't occurred.
Bicuspid ; Crowns ; Finite Element Analysis* ; Incisor ; Molar ; Periodontal Ligament ; Tooth ; Torque*

The purpose of this study was to investigate the tissue response of the rat molar periodontium incident to intermittent orthodontic force. The author intended to observe the healing process of injured periodontium and the response of injured tissue to the resumed force. Oxytetracyclin 50mg/Kg was given to each rat intraperitonially. 5 days later, maxillary 1st molars were moved mesially from the incisors with closed coil spring of 100gram. 7 days later, the appliances were removed and 20mg/Kg of calcein were given intraperitonially to each rat. At the same time, maxillary left 1st molars of 15 rats were moved by the same method, but force was lowered to 20 gram. After 1 day, maxillary left 1st molars of another 15 rats were moved by the same method and 50mg/Kg of oxytetracycline was given intraperitonially. After 4 days, another 15 rats were treated as above. After 7 days, another 15 rats were treated as above. 1,4,7,10 and 14 days after change of force, 3 rats were sacrificed in each group respectively. 2 rats were decalcified, embedded in paraffin, and stained with hematoxylin-eosin stain and with Masson's trichrome stain. Another rat was embedded in polyester resin and undecalcified specimen were made. Microradiograms were taken with the undecalcified sections. Observations were made with light and fluorescence microscope. Following conclusions were made. 1. Connective tissue cells and vessels were infiltrated into the hyalinized tissue from the bony cleft and along the border of the hyalinized tissue with bone and root surface. At the same time, elimination of hyalinized tissue, bone and root resorption occurred. 2. Bone and root were resorbed directly and indirectly. 3. Hyalinized tissue was removed within 5 days after force removal. 4. Hyalinized zone was less extensive and easily removed as the rest period prolonged. 5. Hyalinized tissue developed more rapidly and extensively and lasted over 10 days as the force resumed on the already formed hyalinized tissue.
Animals ; Bone and Bones ; Connective Tissue Cells ; Fluorescence ; Hyalin ; Incisor ; Molar* ; Oxytetracycline ; Paraffin ; Periodontium* ; Polyesters ; Rats* ; Root Resorption

This experiment was performed to study the effect of prostaglandin E2 on tooth movement and root resorption in orthodontically treated cats. Twenty five cats were divided into five groups and closed coil springs delivered 80gm were stretched between upper canine and 3rd premolar. 10microgram of PGE2 was injected locally in the submucosal area of the upper right canine, while the left side served as a control and was injected saline 0.1ml. The distance between canine tip and central cusp tip of the 3rd premolar was measured. Scanning electron photomicrographs were made of the coronal half of the distal root surface of canines and cemental craterings were observed and quantified using point-counting volumetry. Data were analyzed by 2-way ANOVA and paired t-test. The results were as follows: 1. The rate of tooth movement of the PGE2 side was increased, particularly at 1 day, compared with the control side. 2. The rate of tooth movement was minimum from 7 days to 10 days. 3. The resorption of root surface of the PGE2 side was decreased from 4 days to 10 days, compared with the control side.
Animals ; Bicuspid ; Cats* ; Dinoprostone* ; Root Resorption* ; Tooth Movement* ; Tooth*

This study was undertaken to investigate soft tissue profile changes by orthodontic treatment in female patients. Traditional cephalometric appraisal yields data of dubious scientific value, the soft tissue profile forms were evaluated by finite element method. The subject was divided into three groups according to Angle' s classification and each group was composed of 25 female patients averaged aged 12-14 years at the start of treatment. The changes in soft tissue form were evaluated by computing the degree of distortion in each triangle after treatment compared with the triangle before treatment. The conclusions were as follows; 1. The soft tissue profile forms were evaluated by finite element method and independent evaluation of each element by local changes was possible. 2. Maximum and minimum principal strains showed marked variability depending on the particular finite element and each group and Class II, III sample was greater than Class I sample. 3. Soft tissue size changes as a result of orthodontic treatment was not related to those of shape. 4. Soft tissue changes by orthodontic treatment were variable in individual patient, and were not related to Angle' s classification.
Classification ; Female* ; Humans