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In vitro shear bond strength of ceramic brackets.

Korean Journal of Orthodontics.1992;22(2):449-474.

The purpose of this study was to evaluate the in vitro shear bond strengths to enamel and the failure sites of three ceramic brackets and one metal bracket in combination with light cured orthodontic adhesive. The brackets were divided into four groups. Each ceramic bracket group had different bonding mechanisms with adhesive. Group A; metal bracket with foil-mesh base (control group) Group B; ceramic bracket with micromechanical retention Group C; ceramic bracket with chemical bonding Group D; ceramic bracket with mechanical retention and chemical bonding. Forty extracted human lower first premolars were prepared for bonding and 10 brackets for each group were bonded to prepared enamel surfaces with Transbond(R) light cured orthodontic adhesive. Twenty four hours after bonding, the Instron universal testing machine was used to test the shear bond strength of brackets to enamel. After debonding, brackets and enamel surfaces were examined under stereoscopic microscope to determine the failure sites. Statistical analysis of the data was carried out with ANOVA test and Scheffe test using SPSS PC+. The results were as follows: 1. There were statistically significant differences in mean shear bond strengths of three ceramic bracket groups (p<0.05). Shear bond strengths of group C and D were significantly higher than that of group B and shear bond strength of group C was significantly higher than that of group D. 2. Group C and D both had significantly higher shear bond strengths than metal bracket (group A), but there were no significant differences in shear bond strengths between group A and B (p<0.05). 3. The failure sites of four bracket groups were also different. Group C and D failed primarily at enamel-adhesive interface, but group A and B failed primarily at bracket base-adhesive interface. 4. Among all ceramic bracket groups, group B was very similar to metal bracket in the aspect of shear bond strength and failure site.
Adhesives ; Bicuspid ; Ceramics* ; Dental Cements ; Dental Enamel ; Humans

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Comparative analysis of the relationship between basal bone and teeth in normal occlusion and Angle's Class I malocclusion.

Hye Jeong MOON ; Hee Moon KYUNG ; Oh Won KWON ; Jung Min KIM

Korean Journal of Orthodontics.1992;22(2):413-426.

In order to analyze the relationship between teeth and basal bone for the maintainance of the good occlusion, the mesiodistal width of teeth, the basal arch width and the basal arch length were measured on the study model of the normal occlusion group and Angle's class I malocclusion group(non-extraction group, extraction group). The Maximum tooth material, the percentage of basal arch width to maximum tooth material, the percentage of basal arch length to maximum tooth material and the percentage of basal arch width plus basal arch length to maximum tooth material were calculated, and then statistical analysis was done. From this study, the obtained results were as follows; 1. In maxilla, the percentage of basal arch width to maximum tooth material was 46.9+/-2.6% in normal occlusion group, 49.4+/-3.9% in non-extraction group, and 42.5+/-3.3% in extraction group. In mandible, that was 46.6+/-2.4 % in normal occlusion group, 47.5+/-4.0% in non-extraction group, and 42.6+/-2.6% in extraction group. 2. In maxilla, the percentage of basal arch length to maximum tooth material was 33.4+/-1.9% in normal occlusion group, 33.9+/-1.8% in non-extraction group, and 28.7+/-2.5% in extraction group. In mandible, that was 34.4+/-4.3% in normal occlusion group, 36.5+/-1.9% in non-extraction group, and 31.5+/-2.5% in extraction group. 3. In maxilla, the percentage of basal arch width plus basal arch length to maximum tooth material was 80.3+/-3.4% in normal occlusion group, 83.3+/-4.8% in non-extraction group, and 71.2+/-4.3% in extraction group. In mandible, that was 81.0+/-5.2% in normal occlusion group, 84.0+/-5.4% in non-extraction group, and 74.1+/-4.1 % in extraction group. 4. In Maxilla, the 95% confidence interval of the percentage of basal arch width to maximum tooth material was 46.3-47.5% in normal occlusion group, 48.1-50.7% in non-extraction group, and 41.7-47.2% in extraction group. In mandible, that was 46.1-47.2% in normal occlusion group, 46.1-48.8% in non-extraction group, and 42.0-43.3% in extraction group. 5. In maxilla, the 95% confidence interval of the percentage of basal arch length to maximum tooth material was 32.9-33.9% in normal occlusion group, 33.3-34.5% in non-extraction group, and 28.1-29.2% in extraction group. In mandible, that was 33.4-3.4 % in normal occlusion group, 35.8-37.2% in non-extraction group, and 30.9-33.1% in extraction group. 6. In maxilla, the 95% confidence interval of the percentage of basel arch width plus basal arch length to maximum tooth material was 79.5-81.0% in normal occlusion group, 81.6-84.9% in non extraction group, and 70.1-72.2% in extraction group. In mandible, that was 79.8-82.2% in normal occlusion group, 82.1-85.5% in non-extraction group, and 73.1-75.1% in extraction group. 7. There was correlation between maxilla and mandible in the maximum tooth material, the basal arch width, the basal arch length, the percentage of basal arch width to maximum tooth material, the percentage of basal arch length to maximum tooth material and the percentage of basal arch width plus basal arch length to maximum tooth material, but not in the basal arch length of male of the extraction group. *A thesis submitted to the Council of the Graduate School of Kyungpook national University in partial fulfillment of the requirements for the degree of Master of Dental Science in December, 1991.
Gyeongsangbuk-do ; Humans ; Male ; Malocclusion* ; Mandible ; Maxilla ; Tooth*

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A study of the shear bond strength of metal brackets and ceramic brackets and the condition after debonding.

Jung Jin YOON ; Young Kyu RYU

Korean Journal of Orthodontics.1992;22(2):327-343.

Metal brackets and ceramic brackets were bonded to natural teeth, porcelain crowns and gold crowns. After stored in artificial saliva solution for 72 hours at 37degreesC, the shear bond strengths were measured by Instron and compared with them, the bonding sites and bracket bases were examined by scanning electron microscope and light optical stereomicroscope. The results were as follows: 1. The shear bond strengths of the group which metal brackets were bonded to natural teeth and the groups which ceramic brackets were bonded to natural teeth and porcelain crowns were comparable to each other, the shear bond strength of the group which metal brackets were bonded to gold crowns was significantly low. 2. The bond failed predominantly at the bracket base/adhesive interface with the bulk of adhesive remaining on enamel in the group which metal brackets were bonded to natural teeth. 3. The bond failed consistently at the crown/adhesive interface with all of adhesive remaining on the bracket bases in the group which metal brackets were bonded to gold crowns. 4. The bond failed at the enamel or crown/adhesive interface with the bulk of adhesive remaining on the bracket bases in the groups which cramic brackets were bonded to natural teeth and porcelain crowns. 5. The shear bond strengths of the groups which ceramic brackets were bonded to porcelain crowns were not affected by etching time.
Adhesives ; Ceramics* ; Crowns ; Dental Enamel ; Dental Porcelain ; Saliva, Artificial ; Tooth

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Posterior open bite.

Young Hwa SOHN ; Young Il CHANG

Korean Journal of Orthodontics.1995;25(5):641-654.

The purpose of this report is to present the cause and treatment of posterior open bite. Posterior open bite is the open bite limited to posterior teeth. These problem usually are attributed to a mechanical interference with the eruption process, either ankylosis or some soft tissue interference. But, in some patient, lateral open bite is due to a disturbance of the eruptive mechanism itself and other disease or side effect following other treatment. Distinguishing cause of posterior open bite, lack of eruption due to some external interference with eruption or primary failure of eruption mechanism, is important clinically because this determines the prognosis for orthodontic treatments. The characteristics, differential diagnosis with posterior open bite due to other etiologies and the treatment of these problems are presented and discussed.
Ankylosis ; Diagnosis, Differential ; Humans ; Open Bite* ; Prognosis ; Tooth

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A study on the normal dental arch form of Korean adult.

Ha Ik CHUNG

Korean Journal of Orthodontics.1972;3(1):7-13.

Many geometric curves are presented as representative form of normal dental arches by many authors; circle, ellipse, parabola or catenary curve. Among them those except circle seems difficult to be adopted as a guide in ideal arch form construction and practically many orthodontists chose circle as a standard. Author preferred circle of Bonwill's theory in study of anterior teeth alignment of Korean adults. Eighty three dental models which possess proper occlusion and good arch form were selected and copies of their occlusal surfaces obtained by Ricopy machine. The use of Ricopy machine made it possible to draw arch form exactly. Mesiodistal widths of six anterior teeth were measured and they were added to combined mesiodistal width of six anterior teeth. Circle, that include the points of two cuspal tips of canines and one incisal edge of central incisor were drawn. Distances of lateral incisors that are deviated from arc of this circle were measured and classified into four grades by degree and three groups by kind of teeth deviated. By counting the number of samples involved degree of fit of the circle to arch contour of Korean adult was described. Then, size of radius of circle, intercanine width and intermolar width were measured and evaluated their ratios to combined mesiodistal width of six anterior teeth. In normal occlusion of Korean adult anterior teeth seems to be arranged on an arc of circle the radius of which is similar to combined mesiodistal width of six anterior teeth. Intercanine width and intermolar width have rather constant ratios to combined width of six anterior teeth.
Adult* ; Dental Arch* ; Dental Models ; Humans ; Incisor ; Radius ; Tooth

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A biomechanical study on the effect of light wire torquing auxiliary.

Kyung Jin PARK

Korean Journal of Orthodontics.1971;2(1):29-34.

No abstract available.

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The effect of labial inclination on intrusion of the upper and lower incisors by three-dimensional finite element analysis.

Dong Woo KIM ; Hoon Chul YANG ; Gi Tae KIM ; Sung Sik KIM ; Woo Sung SON

Korean Journal of Orthodontics.2003;33(4):259-277.

This study was designed to investigate the position of anteroposterior center of resistance for genuine intrusion and the mode of change of the minimum distal force for simultanous intrusion and retraction of the upper and lower incisors according to the increase of labial inclination. For this purpose, we used the three-piece intrusion arch appliance and three-dimensional finite element models of upper and lower incisors. 1. Positions of the center of resistance in upper incisors according to the increase of the labial inclination were as follows; 1) In normal inclination situation, the center of resistance was located in 6mm behind the distal surface of the lateral incisor bracket. 2) In 10degrees increase of the labial inclination situation, the center of resistance was located in 9mm behind the distal surface of the lateral incisor bracket. 3) In 20degrees increase of the labial inclination situation, the center of resistance was located in 12m behind the distal surface of the lateral incisor bracket. 4) In 30degrees increase of the labial inclination situation, the center of resistance was located in 16m behind the distal surface of the lateral incisor bracket. 2. Positions of the center of resistance in lower incisors according to the increase of the labial inclination were as follows; 1) In normal inclination situation, the center of resistance was located in 10mm behind the distal surface of the lateral incisor bracket. 2) In 10degrees increase of the labial inclination situation, the center of resistance was located in 13mm behind the distal surface of the lateral incisor bracket. 3) In 20degrees increase of the labial inclination situation, the center of resistance was located in 15m behind the distal surface of the lateral incisor bracket. 4) In 30degrees increase of the labial inclination situation, the center of resistance was located in 18m behind the distal surface of the lateral incisor bracket. 3. The patterns of stress distribution were as follows; 1) There were even compressive stresses in and periodontal ligament when intrusion force was applied through determined center of resistance. 2) There were gradual increase of complexity in compressive stress distribution pattern with increase of the labial inclination when intrusion and retraction force were applied simultaneously.
Finite Element Analysis* ; Incisor* ; Periodontal Ligament

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Treatment effects of the Teuscher appliance in skeletal Class II division 1 malocclusion.

Sung Seo MO ; Byung Wha SOHN

Korean Journal of Orthodontics.2003;33(4):247-257.

Various methods have been used on patients with skeletal Class II division 1 malocclusion. The activator, Frankel appliance, headgear, Herbst appliance, and Twin-block appliance are some examples. The ideal treatment effect using these appliances would be to inhibit horizontal and vertical growth of the maxilla while promoting mandibular growth and obtaining optimum dentition. The Teuscher appliance has a simultaneous combined headgear effect with maxillary growth inhibition and an activator effect with mandibular growth promotion. The purpose of this study was to examine how well these effects were clinically obtained and the results are as follows. 1. The forward growth of the maxilla was effectively inhibited. 2. The downward-forward growth of the maxillary dentoalveolar complex was inhibited. 3. Growth promotion of the mandible was not observed. 4. The overjet, overbite, molar key were effectively improved. 5. The protruded upper lip and facial profile were improved.
Dentition ; Humans ; Lip ; Malocclusion* ; Mandible ; Maxilla ; Molar ; Orthodontic Appliances, Functional ; Overbite

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The experimental study of early loading on the Miniplate in the beagle dog.

Yong Koo CHUNG ; Young Jun LEE ; Kyu Rhim CHUNG

Korean Journal of Orthodontics.2003;33(4):307-317.

Conventional osseointegrated titanium implants have many limitations; large size, limited location for placement of the implant, severity of the surgery, discomfort of initial healing, difficulty of oral hygiene and uncontrollable force direction. Recently titanium miniscrew and miniplate have been used for an alternative to conventional dental implant. But in relation to miniplate, miniscrew has disadvantages in that more potential inflammation, light orthodontic force application and limited orthodontic application. This study was conducted to evaluate the effectiveness of miniplate by observing the reactions of peri-implant tissues to early orthodontic and orthopedic loading of titanium miniplate. In four adult beagle dogs 10 miniplates were inserted into the alveolar bone using 20 osseointegrated titanium screws. 4 miniplates were placed in two dogs(dogA, B) and 6 miniplates in two dogs(dogC, D). In dogA, B miniplates were loaded with 200gm of force immediately after placement for 15 weeks. In dogC, D, miniplates were loaded with 400gm of force immediately after placement for 8 weeks. Miniplates of dogA were removed, dogA was healed for 4 weeks, and the area which was removed of miniscrew was examined. Following an observation period, the miniplates including miniscrews and the surrounding bone of dogB and dogC, D were removed, respectively. Undecalcified section along the long axis of miniscrews were made and the degree of osseointegration was examined under the light microscope. The results were as follows. 1. In the histologic features there was direct contact between bone and miniscrew in all groups except one, dogC control group. The loaded miniscrew demonstrated only a slight increase of the osseous proximaty when compared with unloaded miniscrew 2. There was no significant difference of the osseointegration of peri-miniscrew surface between dogB and dogC, D. But dogB showed slightly more increased bone apposition than dogC, D 3. The gingiva overlapping the miniplate and miniscrew showed no inflammatory sign in clinical and histological aspects. 4. The impared hard and soft tissues at the area which was removed of miniscrews showed good healing without inflammatory reaction. 5. The mobility showed slight increase in un-loaded miniplate but that was insignificant. Based on the results of this study, miniplate(C-tube(R)) can be used as a firm osseous orthodontic and orthopedic anchorage unit immediately after insertion.
Adult ; Animals ; Axis, Cervical Vertebra ; Dental Implants ; Dogs* ; Gingiva ; Humans ; Inflammation ; Oral Hygiene ; Orthopedics ; Osseointegration ; Titanium

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Effect of presurgical nasoalveolar molding (PNAM) appliance and cheiloplasty on alveolar molding of complete unilateral cleft lip and palate patients.

Na Young KIM ; Shin Jae LEE ; Seung Hak BAEK

Korean Journal of Orthodontics.2003;33(4):234-245.

The goal of the present study was to evaluate the effects of PNAM appliance and cheiloplasty on alveolar molding. Samples consisted of 16 unilateral cleft lip and palate infants (10 males and 6 female, mean age=37.0 days after birth, average alveolar cleft gap=10.46 mm), who were treated with PNAM appliances by one orthodontist and rotation- advancement cheiloplasty by one surgeon in Seoul National University Hospital. Average duration of alveolar molding treatment was 13.10 weeks and these patients were recalled at average 8.31 weeks after cheiloplasty. These patients' models were obtained at initial visit (T0, mean age : 37.0+/-27.89 days after birth), after successful alveolar molding (T1, mean age : 119.25+/-40.18 days after birth), and after cheilopasty (T2, mean age : 190.81+/-42.78 days after birth). Seven linear and five angular variables were measured using 1 : 1 photometry and soft ware program(V-ceph. Cybermed, Seoul, Korea). Paired t-test was performed to investigate statistical significance at p < 0.05 level. 1. The posterior parts of alveolar segments were the stable structures during alveolar molding treatment period and after cheiloplasty in infants. 2. The closure of cleft gap during alveolar molding was usually due to backward bending of the whole part of the greater segment. 3. Although forward growth of the greater segment was hindered by alveolar molding, it resumed after cheiloplasty. 4. Increase of anterior inter-segment angle after cheiloplasty was due to the molding effect of the lip scar pressuren
Cicatrix ; Cleft Lip* ; Female ; Fungi* ; Humans ; Infant ; Lip ; Male ; Palate* ; Parturition ; Photometry ; Seoul

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