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A longitudinal study on the developmental changes of dental arch width and length.

Korean Journal of Orthodontics.2000;30(1):19-31.

Developmental changes of dental arch width and length from 6.6 to 13.6 years of age have been studied in twenty boys and thirteen girls in Korean school children. A series of 8 dental casts obtained from each child was measured in the intercanine width, intermolar width and arch length. Afterwards, mean value and each standard deviation of each age group and each gender were obtained, and corresponding graphs were drawn. The finding of this study can be summarized as follows : 1.Maxillary intercanine widths increased until age of 13.5 in males and age of 12.5 in females. On the other hand, mandibular intercanine widths increased until age of 11.5 in males and age of 9.6 in females and after there were on changes. 2. Maxillary intermolar widths increased until age of 13.5 but increments reduce from age of 12.5 in both sex. Mandibular intermolar widths increased until age of 13.5 in males and age of 12.5 in females. Annual increments of maxillary intermolar width greater than those of mandibular intercanine width in both sex. 3. Maxillary dental arch lengths increased until age of 10.6 in both sex, and after decreased until age of 13.6. Mandibular dental arch lengths increased until age of 10.5 in males and of 9.6 in females, and after decreased until age of 13.6. 4. Developmental changes of dental arch width and length showed individual variation.
Child ; Dental Arch* ; Female ; Hand ; Humans ; Longitudinal Studies* ; Male

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Mode of tooth movement according to the timing of orthodontic force application after extraction.

Sung Ho HAN ; Hyeon Shik HWANG

Korean Journal of Orthodontics.2000;30(1):9-17.

This study was performed to compare and analyzed the mode of tooth movement according to the timing of orthodontic force application after extraction. The upper right and left third incisors were carefully extracted at three-week interval in four adult dogs. Both canines were used as an anchorage for the bodily movement of the upper second incisors. Orthodontic force of 100gm was simultaneously applied at one week after extraction on one side four weeks after extraction on the other side using NiTi closed coil spring. While orthodontic force was applied for twelve weeks, the amount of tooth movement was measured at every second week with calipers. The animals were sacrificed at twelve weeks and histologic examination was executed to reveal any difference between both sides. The results were obtained as follows: 1. The tooth movement was likely to be faster in four-week side for the first two seeks while faster in one-week side during next two weeks 2. The rate of tooth movement was fastest during four to six weeks period, then decreased gradually. 3. The total amount of tooth movement was likely to be larger in one-week side compared to four-week side. 4 Any damage to tooth and periodontal tissue could not be seen in the histologic section of one-week side. These results suggest that earlier application of orthodontic force is better than later after extraction in terms of the rate of tooth movement.
Adult ; Animals ; Dogs ; Humans ; Incisor ; Tooth Movement* ; Tooth*

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New evaluation chart of stature and weight for Koreans.

Shin Jae LEE ; Young Jae KIM ; Sug Joon AHN ; Tae Woo KIM

Korean Journal of Orthodontics.2006;36(2):153-160.

For orthodontic treatment of growing patients and those which involve long treatment times, knowledge of growth and development are essential. Data from the general growth observation chart being used at present does not reflect the growth transition of modern times. This is because these data are out of date. The present study, therefore, aims to introduce the process of producing a growth curve and growth rate curve based on data which represents a more accurate description of the present situation. The data used were from the 5th nationwide survey, SIZE KOREA 2004 study, carried out by the Technology and Standards Policy Division, Department of Technology and Standards Planning, Ministry of Commerce. Processing and rearranging produced data with variations divided into the three quartiles and the 1st, 5th, 95th and 99th percentiles were included to produce a growth observation chart according to sex, height and weight differences. In the same way, a growth rate curve based on the geometric mean value was produced. The resulting growth charts can be used as an index for growth and development, and used for better communication between the orthodontist, patients and parents.
Commerce ; Growth and Development ; Growth Charts ; Humans ; Korea ; Parents

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A cephalometric study on the velopharyngeal changes after maxillary protraction.

Nam Ki LEE ; Bong Kuen CHA

Korean Journal of Orthodontics.2006;36(2):161-169.

The purpose of this study was to investigate cephalometrically the short term static velopharyngeal changes in 25 patients (10 boys and 15 girls, aged from 5 years 9 months to 12 years 10 months in the beginning of treatment) with skeletal Class III malocclusions who underwent nonsurgical maxillary protraction therapy with a facemask. The linear, angular and ratio measurements were made on lateral cephalograms. Only the change in hard palatal plane angle was negatively correlated with the change in maxillary depth or N-perp to A (p < 0.01). The change in velar angle showed a statistically significant increase (p < 0.001). This change was influenced more by the soft palatal plane angle than by the hard palatal plane angle (p < 0.001). The changes in soft tissue nasopharyngeal depth and hard tissue nasopharyngeal depth showed statistically significant increases (p < 0.001). Correlations between the changes in soft tissue (or hard tissue) nasopharyngeal depth and the change in soft palatal plane angle were significant (p < 0.05). The increase in hard palate length was statistically significant (p < 0.001). The change in hard palate length was negatively correlated with the change in soft tissue nasopharyngeal depth (p < 0.05). The change in need ratio S (C) showed a statistically significant increase (p < 0.001). But this difference was within the normal range reported by previous studies. These findings indicate that the velopharyngeal competence was maintained even if the anatomical condition of the static velopharyngeal area were changed after maxillary protraction.
Female ; Humans ; Malocclusion ; Mental Competency ; Palate, Hard ; Reference Values

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A comparative study of electroplating and electroless plating for diameter increase of orthodontic wire.

Jae Nam KIM ; Jin Hyoung CHO ; Young Eun SUNG ; Ki Heon LEE ; Hyeon Shik HWANG

Korean Journal of Orthodontics.2006;36(2):145-152.

The purpose of this study was to evaluate electroless plating as a method of increasing the diameter of an orthodontic wire in comparison with eletroplating. After pretreatment plating of the 0.016 inch stainless steel orthodontic wire, electroless plating was performed at 90 degrees C until the diameter of the wire was increased to 0.018 inch. During the process of electroless plating, the diameter of the wire was measured every 5 minutes to examine the increasing ratio of the wire' diameter per time unit. And to examine the uniformity, the diameter at 3 points on the electroless-plated orthodontic wire was measured. An X-ray diffraction test for analyzing the nature of the plated metal and a 3-point bending test for analyzing the physical property were performed. The electroless-plated wire group showed a increased tendency for stiffness, yield strength, and ultimate strength than the electroplated wire group. And there was a statistically significant difference between the two groups for stiffness and ultimate strength. In the electroless-plated wire group, the increasing ratio of the diameter was 0.00461 +/-.00003 mm/5 min (0.00092 mm/min). In the electroplated wire group, it was 0.00821 +/-.00015 mm/min. The results of the uniformity test showed a tendency for uniformity in both the plating methods. The results of this study suggest that electroless plating of the wire is closer to the ready-made wire than electroplating wire in terms of the physical property. However, the length of plating time needs further consideration for the clinical application of electroless plating.
Electroplating* ; Orthodontic Wires* ; Stainless Steel ; X-Ray Diffraction

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Evaluation of friction of ceramic brackets in various bracket-wire combinations.

Jung Yul CHA ; Kyung Suk KIM ; Dong Choon KIM ; Chung Ju HWANG

Korean Journal of Orthodontics.2006;36(2):125-135.

The purpose of this study was to measure and compare the level of frictional resistance generated from three currently used ceramic brackets; 1, Crystaline V(R), Tomy International Inc., Tokyo, Japan; 2, Clarity(R), 3M Unitek, Monrovia, CA, USA; 3, Inspire(R), Ormco, Orange, CA, USA; with composite resin brackets, Spirit(R), Ormco, Orange, CA, USA; and conventional stainless steel brackets, Kosaka(R), Tomy International Inc., Tokyo, Japan used as controls. In this experiment, the resistance to sliding was studied as a function of four angulations (0 degrees, 5 degrees, 10 degrees, and 15 degrees) using 2 different orthodontic wire alloys: stainless steel (stainless steel, SDS Ormco, Orange, CA, USA), and beta-titanium (TMA, SDS Ormco, Orange, CA, USA). After mounting the 22 mil brackets to the fixture and .019 x .025 wires ligated with elastic ligatures, the arch wires were slid through the brackets at 5 mm/min in the dry state at 34 degrees C. Silica-insert ceramic brackets generated a significantly lower frictional force than did other ceramic brackets, similar to that of stainless steel brackets. Beta-titanium archwires had higher frictional resistance than did stainless steel, and all the brackets showed higher static and kinetic frictional force as the angulations increased. When the angulation exceeded 5 degrees, the active configuration emerged and frictional force quickly increased by 2.5 to 4.5-fold. The order of frictional force of the different wire-bracket couples transposed as the angle increased. The silica-insert ceramic bracket is a valuable alternative to conventional stainless steel brackets for patients with esthetic demands.
Alloys ; Ceramics* ; Citrus sinensis ; Family Characteristics ; Friction* ; Humans ; Japan ; Ligation ; Orthodontic Wires ; Stainless Steel ; Steel

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Early histological change in hard tissue from orthodontic force placed on microscrews in ovariectomized rats.

Dea Seung LEE ; Jin Woo LEE ; Moon Jung CHANG

Korean Journal of Orthodontics.2006;36(2):103-113.

Most elderly women experience a decrease in their bone density due to a deficiency of calcium intake, ovariectomy, or menopause. This study evaluated the usability of the microscrew as a skeletal anchorage system in these orthodontic treatment cases, using rats as a research group. The 4 month old sprague-dawley species rats were divided into two groups, the OS (Ovariectomy Screw), and the SS (Sham operation Screw) group. In both the OS and SS groups, microscrews were implanted into the palatal bone between the upper molar teeth and two upper incisors were retracted using NiTi coil spring with 75 g of force. After 3 days, the again after 7 days, 7 rats in each group were sacrificed. Three days before they were sacrificed, Alizarin red S was intraperitoneally injected, and their maxillary bone, tibia and blood from their hearts were taken. The components of the extracted blood were biochemically analyzed and non-decalcified grinding resin sections for maxillary bone and tibia were made. The sections were examined with a polarization microscope, and fluorescent microscope. Smaller concentrations of Ca and P, the inorganic substances closely related to bone density, were found in the extracted blood of the OS group. Both OS and SS groups showed a possibility of bone remodeling with a high concentration of ALP after 7 days. An increase in bone density on the tension and compression sides of the microscrew and the tension side of the tooth for both OS and SS groups was confirmed with a polarization microscope. However, the bone density of the pressure side of the tooth and apical side was decreased. More deposits of Alizarin red S in the bone after 7 days rather than 3 days seen with a fluorescent microscope suggested the existence of new bone formation.
Aged ; Animals ; Bone Density ; Bone Remodeling ; Calcium ; Female ; Heart ; Humans ; Incisor ; Infant ; Maxilla ; Menopause ; Molar ; Osteogenesis ; Osteoporosis ; Ovariectomy ; Rats* ; Rats, Sprague-Dawley ; Tibia ; Tooth

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The effect of indomethacin on the matrix metalloproteinases in canine permanent tooth eruption.

Yoon Goo KANG ; Jong Hyun NAM ; Ki Soo LEE

Korean Journal of Orthodontics.2006;36(2):91-102.

Tooth eruption requires remodeling of surrounding tissues. This study was aimed to investigate the effect of indomethacin on the dental follicle and paradental tissues during tooth eruption by observing the distribution and expression of MMP by the immunohistochemical method. Ten mongrel dogs of ten to twelve weeks old were divided into 5 groups; four experimental groups administered indomethacin 2 mg/Kg/day and 8 mg/Kg/day orally 2 times a day for 14 days and 7 days respectively, and the control group was administered a placebo. Permanent teeth before eruption and their surrounding tissues were selected and excised. H and E staining and immunohistochemical stainings of MMP-3 and -9 were performed and examined under the light microscope. Osteoclasts, osteoblasts, periodontal ligament cells, ameloblasts and odontoblasts of the control group all expressed MMP-3 and -9. In the experimental group, osteoclasts, osteoblasts and periodontal ligament cells showed reduced expression of MMP-3 and -9. Magnitude of MMP reduction in the experimental group showed a time and dose of indomethacin administration dependent manner. These results show that indomethacin inhibited MMP-3 and -9 expression in the dental follicle and surrounding tissues and suggest that when indomethacin is administered for long periods, tooth eruption could be delayed.
Ameloblasts ; Animals ; Dental Sac ; Dogs ; Indomethacin* ; Matrix Metalloproteinases* ; Odontoblasts ; Osteoblasts ; Osteoclasts ; Periodontal Ligament ; Tooth Eruption* ; Tooth*

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Submentovertex cephalometrics in Korean adults.

Dong Seok NAHM ; Chung Hoon SUHR ; Won Sik YANG ; Young Il CHANG

Korean Journal of Orthodontics.2000;30(1):1-7.

It is important that the orthodontist accurately assess the degree to which facial asymmetry contributes to a given malocclusion before treatment planning. P-A, submentovertex and verticosubmental view have been used in the assessment of facial asymmetry. Among them, submentovertex view is rarely used because it has low reproducibility and is short of normal data and proper analysis method. The purpose of this study was to develop a submentovertex cephalometrics and obtain normal data in Korean adults. The subjects consisted of 40 normal adults (male : 22, female : 18) without the experience of orthodontic treatment. We find the 2 angular and 9 linear measurements. Though submentovertex cephalomentrics has the limitation in comparing the absolute length between right and left, it is useful to examine the relationship of skeletal and dental midline, the shape and location of condyle head and the shape of mandibular body in submentovertex view. Therefore, if we understand the limitation of submentovertex cephalomentrics and use lateral, P-A submentovertex cephalomentrics together, we will measure the location and amount of skeletal disharmony more exactly.
Adult* ; Facial Asymmetry ; Female ; Head ; Humans ; Malocclusion

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Changes of symphysis morphology after chincup treatment.

Sun KANG ; Dong Cheol PARK ; Jong Ghee KIM

Korean Journal of Orthodontics.2000;30(1):33-41.

Although it is well known that the chincup, used to correct a skeletal class III malocclusion in growing children, reduce the mandibular prognathism by arresting the growth of the mandibular length and rotating the mandible posteroinferiorly, the majority of the studies about chincup is focused on condylar head that plays an important role in mandibular growth. The aim of this study was to evaluate the morphologic change of the mandibular symphysis where extraoral force is applied directly during chincup treatment. The data for this study were obtained from lateral cephalometric radiographs of 62 growing children(chincup group:32, control group:30) with mixed dentition who had been accepted for the orthodontic treatment at Chonbuk National University Dental Hospital. The results were as follows : 1. Symphysis height was increased both in chincup therapy group and control group during treatment. Symphysis depth was decreased or maintained the initial values in chin cup therapy group, whereas increased in control group. Posterior symphysis depth was decreased both in chin cup therapy group and control group, but anterior symphysis depth was increased in control group, whereas decreased in chincup therapy group. 2. Chin depth and chin curvature were increased in control group, whereas maintained or decreased in chincup therapy group during treatment. Chin angle, menton angle and symphysis angle were decreased in control group, whereas increased in chincup therapy group. It suggested that bone deposition in pogonion area that occur normally with mandibular growth was suppressed by direct contact of chincup. 3. When growing children wear chincup, symphysis morphology was maintained due to inhibition of forward growth at mandibular symphysis. It may be due to the suppression of bone deposition in anterior part of symphysis.
Child ; Chin ; Dentition, Mixed ; Head ; Humans ; Jeollabuk-do ; Malocclusion ; Mandible ; Prognathism

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