Recently, straight-wire appliance is widely used with great concern in clinical orthodontic field. The purpose of this study was to collect the information of the straight-wire appliance and to determine the crown inclination in clinical orthodontics. The author analyzed the study model of 78 individuals with normal occlusion. The obtained results were as follows. 1. Mean, maximum value, minimum value and standard deviation of crown inclination of upper and lower teeth were obtained. 2. The lingual crown inclination of upper tooth had constant value from first premolar through second molar, the lingual crown inclination of lower tooth progressively increased from canine through second molar 3. As Howes' ratio was decreased, the crown inclination of upper incisors was increased. 4. Narrowing the upper arch, the crown inclination of upper incisors was increased.
Bicuspid ; Crowns* ; Incisor ; Molar ; Orthodontics ; Tooth

To help arrive at a more accurate diagnosis of anteroposterior apial base relationship on each individual case, it is important to compare the interpretation in the same population on a longitudinal basis. The author studied on the changes of the anteroposterior apical base relationship using serial lateral cephalometric roentgenograms of 15 boys and 27 girls aged from 6 to 13 years of Korean children. Fallowing results were obtained: 1. Norms of Korean boys and girls were established. 2. With ages, there was a gradual decrease of ANB, AXB angle, and there was a gradual increase of Facial angle, A-B plane angle, APDl. 3. Wits appraisal does not change significantly with ages. 4. No significant differences were observed in the changes between male and female subjects for all absolute values between the ages of 6 years and 12 years, but significant differences were observed in ANB, AXB, A-B plane angle of the age of 13 years. No significant differences were observed in the changes between male and female subjects for all incremental values between the ages of 6 years and 13 years.
Child ; Diagnosis ; Female ; Humans ; Longitudinal Studies* ; Male

This study was performed to establish the cephalometric standards and growth change of Korean teen-age group by Ricketts analysis. A roentgrnocephalometric study was made from 365 subjects, that consist of 159 males, 206 frmales with normal occlusion, acceptable profile and no history of otrhodntic and prosthodontic treatment. The results were as follows: 1. The tables of means, standard deviation from measured values were made, (male, female, both sex). 2. The tables of regression rquations from measured values were made to establish the relationship between age and each item. (male, female, both sex). 3. All linear measurements of each item m male were treater than m females. 4. Items which show more linear than any other items were condyle axis, facial axis length, corpus length and uppwe molar position.
Axis, Cervical Vertebra ; Female ; Humans ; Male ; Molar ; Prosthodontics

With modification of the acid etch technique and improvements of the physical and mechanical properties of the acrylic reain, the removal of directly bonded attachments and the finishing of the underlying enamel have become an acute clinical problem. This study was to evaluation the efficacy of recently introduced instrumentation and techniques to remove bonded brackets and residual resin, and restore the affected enamel surface to an acceptable clinical condition. Fortyeight premolar which were scheduled for extractio for orthodontic purposes were bonded with brackets usion super-C oftho. Four additional premolars with untreated surfaces were used as controls. After one weak the grackets were removed and the residual resin removed by hand scaler, green stone, green rubber wheel, sandpaper disc, tungsten carbide bur, Sof-lex disc. Half the experimental teeth were given a final pumicing and then all were extracted and stored in 50 percent ethanol. The scanning electron microscopy was used to evalusted the enamel surface. Following results were obtained; 1. A satisfactory result was obtained by means of the Sof-lex disc. 2. The order of the scratch formation was the procedure using hand scaler, green stone, tungsten carbide bur, sandpaper disc, green rubber wheel, and Sof-lex disc. 3. The procedures using green stone and tungsten carbide bur showed many groove formations and the other procedures showed none. 4. Final pumicing serves effectively to remove residual adhesive and restore the enamel surface.
Adhesives ; Bicuspid ; Dental Enamel* ; Ethanol ; Hand ; Microscopy, Electron, Scanning* ; Rubber ; Tooth ; Tungsten

The author compared patients with extreme variations in MP-SN angle with normal group in order to examine the relationship between the MP-SN angle and other skeletal and dental parameters. The results were as follows; 1. The OP-SN angle and OP-MP angle decreased as the MP-SN angle decreased. 2. As the MP-SN angle decreased, the skeletal and dental components became more anteriorly situated. 3. In high MP-SN group, TFH, UFH, LFH, OP-MP, ADH increased nore than those in average MP-SN group. 4. The RH/TFH ratio decreased as the MP-SN increased.
Humans

The physical tooth movement by orthodontic force is based upon alveolar bone resorption at compression site and new bone formation at tension site of the alveolar socket. The function of the cyclic AMP is to participate not only in initial action of bone cells by mechanical forces but also in the continuous cellular response leading to bone remodelling. This experiment was performed to clarify the role of cyclic AMP in bone remodelling by mechanical force In the NORMAL group, the DIABETES group and the INSULIN TREATED group. The 72 rats were divided into the NORMAL group, the DIABETES group and the INSULIN TREATED group. The same orthodontic forces were applied to the rats of 3 groups. These rats were treated for periods of time ranging from 1 hour, 1 day, 7 days, 14 days, 21 days and 28 days. The samples of alveolar bones were obtained from compression and tension sites surrounding the tipping teeth from NORMAL, DIABETE and INSULIN TREATED rats. The samples were assayed for cyclic AMP by the cyclic AMP RIA kit. The results were as follows 1. The cyclic AMP levels of alveolar bone in compression and tension sites showed initial decrease, then increased and remained elevated by the time consuming. 2. The highest cyclic AMP level showed in the DIABETES group and the lowest level was In the NORMAL group. 3. The cyclic AMP levels In the INSULIN TREATED group was similar with the NORMAL group in control and tension sites, but in the compression sites it was similar with the DIABETES group.
Animals ; Bone Resorption ; Cyclic AMP* ; Insulin* ; Osteogenesis ; Rats* ; Tooth ; Tooth Movement

The purpose of this study was to investigate the relationship among the activity of the craniofacial muscle and craniofacial form and occlusal state. In this study, subjects were consisted of 23 male adults with skeletal Class III malocclusion and 30 male adults with normal occlusion. The measurements in oral exam, lateral cephalograrn, and F.M.G. recordings of anterior temporal, masseter, and upper lip muscles at rest position, clenching in centric occlusion, chewing of gum, swallowing of juice, were analyzed with SPSS system. The results were as follows: 1. At rest position upper lip muscle activity of skeletal Class III group was significantly higher than that of normal group. 2. Both clenching and chewing masseter and temporal muscle activity of normal group were significantly higher than that of skeletal Class III group. 3. During swallowing of juice, upper lip muscle activity of skeletal Class III group were significantly higher than that of normal group. 4. The activities of masseter and anterior temporal muscle during clenching and chewing were significantly correlated with hypodivergent facial form and number of occluded teeth. 5. The activity of upper lip during swallowing had positive correlation with mandibular prognathism.
Adult* ; Deglutition ; Gingiva ; Humans ; Lip ; Male ; Malocclusion* ; Mastication ; Muscles ; Prognathism ; Temporal Muscle ; Tooth

Recently, rapid palatal expansion technique is widely used for the correction of the skeletal imbalance in Cl III malocclusion patients. There were many studres about the cephalometric changes to rapid palatal expansion but quantitative analysis were small. The purpose of this study was to analysis the stresses and displacement of the maxilla in human dry skull to rapid palatal expansion. The results were as follows. 1. The anterior portion of palate show more lateral and inferior displacement than the posterior portion. But the posterior portion show more anterior displacement. 2. In transpalatal suture area, the medial portion show more lateral displacement than the medral portion. 3. In mid-sagittal plane, the power portion (palatal area) of maxilla show more anterior, lateral, inferior displacement than the upper portion (forntamaxillary stuture area). 4. In zygomatic arch, the abjacent area to maxilla show tensile stresses and the abjacent area to forntal bone show compressive stresses. 5. The sequence of stress bearng area to R.P.E is upper retromolar area, upper 1st molar, 1st premolar, 2nd premolar, anterior segment of teeth.
Bicuspid ; Finite Element Analysis* ; Humans* ; Malocclusion ; Maxilla* ; Molar ; Palatal Expansion Technique ; Palate ; Skull ; Sutures ; Tooth ; Zygoma

Retraction of canines represents a fundamental stage in a considerable number of orthodontic treatment. Correct position of the canine after retraction is most important for function, stability, and esthetics. The purpose of this study was to investigate the stress in the periodontal tissue at the initial phase during canine retraction using various types of sectional retraction springs, by finite element method. Three dimensional model of tooth, periodontal ligament, bone and eight springs were simulated and tested. The following results were obtained. 1. In sectional retraction springs, increasing number of helix and the closed loop in preference to the open loop provided an decrease in horizontal force. Without angulating the arms of spring, the T-loop revealed the highest Moment-to-force ratio. 2. The Moment-to-force ratio raised by angulating mesial and distal arms of spring, but very large horizontal force was applied to canine. 3. When optimal force and optimal moment was applied to canine, the stress induced was homogeneous and the difference of stress value from cervix to the apex was little.
Arm ; Cervix Uteri ; Esthetics ; Female ; Periodontal Ligament ; Tooth

This study was performed to aid for the case analysis and diagnosis of the maxillofacial deformities. A cephalometric analysis was made form 101 subjects over 18 years old, that consisted of 46 males and 55 females with normal occlusion, acceptable profile. The results of this study were obtained as follows: 1. The tables of normals in adult male and female were made. 2. The angles of SNO were 65.5degrees in male and 65.3degrees in female and the horizontal linear measureaments from 0 to NA(O-NA) were 9.0mm in male and 8.9mm in female. 3. The cranial base angles (SN-FH) were 8.2degrees in male and 10.3degrees in female and the mandibular plane angles (OP-HP) were 28.1degrees in male and 26.2 in female. 4. The correlation of (O-NA) to S-O/S-A and S-O/S-N were higher than SNO, and the correlation of (N-A) to SNA and (N-B) were high.
Adolescent ; Adult* ; Congenital Abnormalities ; Diagnosis ; Female ; Humans ; Male ; Skull Base