Biomechanics in various mandibular widening procedures / 대한치과교정학회지

Mandibular widening is one method of mandibular distraction osteogenesis, which has anatomic limitations such as curved surface, mandibular condyle and narrow arch. The purpose of this study was to understand the biomechanics of various mandibular widening procedures. Experimental models consisted of 6 groups according to different osteotomy lines and distractor positions. The results of this study showed different expansion patterns, which meant the need for proper approaches in mandibular widening.

A comparative study of soft tissue profile between non-surgical group and orthognathic surgery combined group in skeletal class III patients

A case report of functional treatment in severe condyle resorption female adult patient

Clinical study on a surgically assisted rapid orthodoontics using dentoalveolar distraction osteogenesis

Mandibular clinical arch forms in Koreans with normal occlusions / 대한치과교정학회지

The purpose of this study was to clarify morphologic characteristics between mandibular clinical arch forms in Koreans with normal occlusions. The study included data from 102 Koreans. The most facial portion of 13 proximal contact areas was digitized from photocopied images of the mandibular dental arches. Clinical bracket points were calculated for each tooth based on mandibular tooth thickness data. Four linear and two proportional measurements were taken. The dental arches were classified into ovoid, square and tapered forms. The frequency distributions of the three mandibular arch form classifications were determined and compared between male and female subjects. No significant differences in arch form size were found between the sexes. However, there were a few differences in molar width. It was useful to classify mandibular clinical arch forms present in normal occlusion samples into ovoid, square and tapered categories. The frequency of the ovoid form was the highest, and that of the square form was the second highest. The tapered arch form was found in less than 10 percent of subjects. No significant differences in their frequency distributions and dimensions were shown between males and females.

Tissue changes of pulp and periodontium on rapid tooth movement with osteotomy in dogs / 대한치과교정학회지

The movement of tooth-bone segments by osteotomy can simultaneously shift tooth and surrounding alveolar bone in a relatively short period. The purpose of this study was to evaluate the tissue changes in pulp, periodontal ligament, and alveolar bone in rapid tooth-bone movement with osteotomy. The mandibular 3rd premolar of a dog was extracted and cortical bones of the buccal and lingual area were eliminated, and then cortical bones around the mesial and distal area of root, and below the root apex of the mandibular 4th premolar were osteotomized. After a one-week latency period, a tooth-borne distraction device was activated for 6 days. And pulp, periodontal ligament and alveolar bone were evaluated clinically, radiologically, histologically and immunohistochemically at 0, 1, 2, 4, 6, 8 weeks of the consolidation period and conclusions were reached as follows. 1. Latency period didn't affect total amount of tooth movement and healing process of tissue during consolidation period. 2. Bone formation continued through 8 weeks of consolidation in distracted side, with a high peak at 1-2 weeks, and the lowest at 6-8 weeks of consolidation. 3. At 1 week of consolidation, alveolar bone resorption, osteoclast appearance and inflammatory cell infiltration were the most active, and dentinoclasts characteristically appeared on the pulp and pressure side of the periodontal ligament 4. The expression of TGF-beta was area-specific, as it was strong-positive at bone matrix, osteoblast, osteoclast of alveolar bone, and dentinoclast inside pulp, but weak in pulp, cementoblast and acellular cementum. 5. The expression of TGF-beta was generally observed at the initial 1-2 weeks of consolidation at vessels, periodontal ligament cells, and osteoblast near alveolar bone on the distraction side of the periodontal ligament, and was significantly decreased after 6 weeks of consolidation.

Case reports of antero-posteior movement with distraction osteogenesis in maxillary anterior segment

Distraction osteogenesis in facial asymmetry patient / 대한치과교정학회지

Distraction osteogenesis is a well-estabilished procedure of membraneous bone formation and has been used to correct craniofacial deformities in dentofacial orthopedic-surgery area for decades. In this article, distraction osteogenesis is used for treatment of facial asymmetry. The patient underwent procedures to lengthen the mandibular ramus and body. After distraction, orthodontic treatment was done for occlusal settling.

Corticotomy and the Intrusive Tooth Movement / 대한치과교정학회지

Tooth movement facilitated by corticotomy and distraction osteogenesis, new paradigm in orthodontics, was discussed. Intrusive tooth movement of anterior or posterior teeth was thought to be difficult or impossible. In this study, a part of cortical bone, which was a sort of resistance to tooth movement in alveolar bone, was removed. On the other hand, active bone deposition was made possible in the tension side. That was the main concept of tooth movement facilitated by corticotomy and distraction osteogenesis. Teeth moved at such a speedy rate as we could not imagine in conventional tooth movement, which lead to the reduction of total treatment period. And intrusive movement was possible without a side effect, for example, root resorption or the periodontal breakdown. Those were the superior aspects to the conventional orthodontics.

Distraction osteogenesis in collapsed mandible arch patients by accidents / 대한치과교정학회지

The symphyseal mandibular fractures due to accidents happened in form of collapsed transeverse arch and multiple teeth loss. And the collapsed transverse arch in mandible occurs with unilaterally or bilaterally. So that patient needs to recover arch width. Conventional approaches, however, are difficult to get appropriate transverse arch correction. Distraction osteogenesis is a unique form of clinical tissue engineering and biologic process of new bone formation between bone segments that are gradually separately by incremental traction. Distraction osteogenesis is considered that great potential for correcting transverse mandibular deficiencies. In this paper, distraction osteogenesis applied to patients who had a unilateral or bilateral collapsed arch width in mandible. But it was necessary secrutinize consideration about periodontal conditions, biomechanical vectors, TMJ adaptations, and neuromuscular change during distraction osteogenesis period.

A STUDY OF TGF-Beta EXPRESSION DURING PALATOGENESIS IN RATS WITH CLEFT PALATE INDUCED BY BAPN

Reports of mandibular symphysis widening with distraction osteogenesis / 대한치과교정학회지

Transverse skeletal deficiency is a common clincal problem associated with narrow basal and dentoalveolar bone. The clinical characteristics of transverse deficiency presents with anterior crowding and posterior buccal crossbite. Orthodontic expansion, using lip bumper and functional devices, was recommanded for younger ages. However, expansion of lower anterior area in older patients is unstable and tends to relapse toward the original dimension. Distraction osteogenesis is a unique form of clincal tissue engineering and biologic process of new bone formation between bone segments that are gradually separately by incremental traction. Distraction osteogenesis was considered that great potential for correcting transverse mandibular deficiencies. In this paper, a case of treated transverse deficiency patients with distraction osteogenesis using tooth-borne and tooth & bone-borne distractor is presented.

A study of TGF-beta expression patterns in cleft palate formed rats induced by BAPN / 대한치과교정학회지

Cleft palate has been studied with epidemiologic and molecular methods, and many etiologic factors have been examined closely. Among the research methods, biologic molecule research has been the most important method for cleft palate formation study. The TGF-beta played an important role in cell migration, epithelial-mesenchymal transdifferentiation, extracellular matrix synthesis and deposition. But there was not much research on the correlation cleft palate induced by beta-aminonitroproprionitrile(BAPN) and TGF-beta expression. The purpose of the present study was to examine how TGF-beta is expressed in cleft palate rats. 4 Timed-pregnant Sprague-Dawley rats were obtained on the 10th gestation day. On the 13th day of gestation, BAPN-monofumarate salts ((C3H6N2)2.C4H4O4) were individually, orally administered to 3 pregnant rats at a ratio of 1g/kg body weight. And 4 pregnant rats were sacrificed on day 20 post coitus (p.c.). The TGF-beta expression in the cleft formed rats fetuses showed the following patterns : 1. Osteoblast and mesenchymal cells of the cleft palate rats were of low expression compared with those of the control rats. 2. The cleft palate rats didn't show any difference in the TGF-beta expression of osteocyte from the control rats. 3. In western blot analysis, the thickness of band of TGF-beta in the cleft palate rats was thinner and more diluted than that of the control rats.

A study of osteonectin expression patterns in BAPN-induced cleft palate formed rats / 대한치과교정학회지

The purpose of this study was to investigate osteonectin expression patterns in cleft palatecompare to normal palate rats. We used 4 pregnant rats, and beta-aminoproprionitrile was oral dose to rat according to lg/kg body weight at gestation days 13 to induce cleft palate. Total 6 fetus was got with cleft formed, then 3 fetus was used for immunohistostain and 3 fetus was used for western blot analysis. Expression patterns of osteonectin in mesenchymal cells of cleft palate was more dilute to mesenchymal cells of normal palate with immnunohistostain, and width and length of band of maxilla in cleft palate was more thin than maxilla of normal palate with western blot study.

A study on relationship between TMD and skeletodental form in long face patterns / 대한치과교정학회지

Forty-four females with normal temporomandibular joint were compared with fifty-one females with abnormal temporomandibular joint, An orthodontic study model and lateral cephalometric radiographic were used to investigate the relationship between TMD group and non-TMD group in long face patterns. The result were followed that : 1. There were no significant in oberbite and overjet amount. 2. A mandibular 1`st molar inclination and height to the mandibular plane were more mesial inclined in TMD group. 3. The functional factors, which were craniocervical posture, tongue posture and hyoid bone position, were no significant.

A study on concentration and application time of lithium sulfate-contained polyacrylic acid for adequate crystal growth / 대한치과교정학회지

The purpose of this study was to compare shear bonding strengths and debonding patterns of the ceramic brackets attached on the crystal which were grown on the enamel surface of a tooth with different concentrations of lithium sulphate-contained polyacrylic acid in different application times. Four kinds of concentrations of mixed solutions were made and applied to the enamel surface on extracted human premolars. The solutions were made by adding 0.3M or 0.6M of lithium sulfate to 50% or 65% of polyacrylic acid with 0.3M sulfuric acid. The solutions were applied for 30 or 60 seconds. After bonding, a universal testing machine was used to measure the shear bond strength, and then observations were made of debonding patterns through the stereoscope. And the enamel surface was observed through the scanning electron microscope to examine the pattern of crystal growth and debonding. The results were as follows: 1, Shear bond strength in the enamel surface treated with 50% polyacrylic acid was higher than that with 65% polyacrylic acid. 2. There were no statistical differences in shear bond strength according to concentration of lithium sulfate and application time of solutions. 3. Enamel surface was almost free of resin debris after debonding. 4. Enamel surface treated with 50% polyacrylic acid showed higher density of crystal growth than that with 65% polyacrylic acid under scanning electron microscope.

A study on the shear bond strength of light-cured glass ionomer cement / 대한치과교정학회지

The purpose of this study was to evaluate the shear bond strength of light cured glass ionomer cement to enamel surface which treated with 37% phosphoric acid, 10% polyacrylic acid, 1.23% acidulated phosphate fluoride gel and no etching agent. To compare the shear bond strength of glass ionomer cement, light-cured composite resin and chemically-cured composite resin were empoloyed as controls. Eight experiments groups were composed. 10 specimens of each group were bonded by metal bracket by tested in universal testing machine for shear bond strength, in stereoscope for adhesive remnants index. The data were evaluated statistically by SPSS/PC+. The results were as follows. 1. Among the groups of 37% phosphoric acid treated and dry and bonded with light cured glass ionomer, light cured composite resin, and chemically cured composite resin, the shear bond strength of glass ionomer group showed no significant difference to the others, but the shear bond strength of chemically cured resin showed statistically lower than that of light cured resin p<0.05). 2. The shear bond strengths of glass ionomer cement to enamel treated group with 1.23% acidulated phosphate fluoride gel and 10% polyacrylic acid and 37% phosphoric acid showed statistically higher than that of no etched enamel group(p<0.05). 3. In the groups of glass ionomer cement, the presence of moisture was not significantly effect to the shear bond strength (p<0.05). 4. After debonding, no etched enamel group showed less residual materials on the. enamel surface than the group of enamel etched with 37% phosphoric acid.

The effects of craniocervical posture and the position of tongue and hyoid bone on craniofacial morphology / 대한치과교정학회지

The purpose of this study was to examine the associations of head posture, the position of the tongue or the hyoid bone to craniofacial structure. Cephalograms taken in Natural head position(NHP) of 90 dental students (50 in male, 40 in female, 20 to 30 years in age) were traced and measured using the extracranial true horizontal and vertical lines. The obtained results were as follows; 1. There was no sex difference in head posture, but the hyoid bone was placed anteroinferiorly in male more than in female and anteroinferior inclination of the hyoid bone showed greatly in male. 2. The more inclined was the cervical column, the less prognathic was the face in natural head posture, and the larger cervical curvature, the more vertical pattern of the face. 3. The less small showed raniocervical angulation, the more anteriorly placed was the hyoid bone to the cranial base, and there was no significantly association between craniocervical angulation and the vertical position of the hyoid bone. 4. The more prognathic was the mandible, the more anteriorly placed was the hyoid bone, and there was slightly association between the crap ofacial morphology and the vertical position of the hyoid bone.

A study on the variations of the soft tissue profile contour in relation to the skeletal patterns / 대한치과교정학회지

The purpose this study was to investigate the variations of the soft tissue profile contour in relation to the skeletal patterns and to confirm the correlation of soft tissue angles to the sagittal or vertical skeletal elements. Lateral cephalograms of 79 cases which were older than 17 years in age, were traced and statistically analyzed. The obtained results were as follows : 1. Nasolabial angle, interlabial angle, lower lip angle, mentolabial angle, symphyseal angle showed the significant differences between skeletal Class II and skeletal. Class III group, but nasofrontal, upper lip, mentolavbial, and symphyseal angles showed the significant differences between high angle low angle group. 2. ANB value showed the dignificant positive correlation to nasolabial, symphuseal, and interlabial angles and the significant negative felation to lower lip angle. 3. SN-GoMe vlue showed the significant positive correlation to mentolabial, symphyseal, nasofrontal, and upper lip angles. 4. Soft tissue profile contour in SK. Class II group showed greater accofdance to SN-GoMe value than those in SK. Class III group.

A photoelastic study on the stress distribution in bone by the transpalatal lingual arch / 대한치과교정학회지

The purpose of this study was to investigate the stress distribution and intensity derived from the transpalatal lingual arch in the investing bone composed of photoelastic material(PL-3). The transpalatal lingual arch wire was deflected in the horizontal and vertical direction to give the various conditions. The two-dimensional photoelastic stress analysis was performed, and the stress distrebution was recored by photofraphy. The results were as follows: 1. In bilateral expansion, as horizontal deflection was singly applied, the stress was more concentrated on the root apex in square free end than round. In square free end, as vertical deflection was increased gradually, the black line meaning center of rotation moced inferiorly togerher with the increment of whole fringes. 2. In application of vertical deflection on anchorage side for unilateral expansion, the stress distribution that expansive force leaned to expansion side was observed. As vertical deflection increased, the extruding stress was obesrved on molar of expansion side. And as horisontal deflection increased, the tipping stress on the molar of anchorage side was observed. 3. In unilateral rotation with the asymmetric toe-in, the fringe appeared on the distal aspect of root apex.