The purposes of this study were: 1) to determine the normal range of CR-CO discrepancy in normal occlusion group: 2) to evaluate the changes of condylar position and craniofacial morphology between centric relation and centric occlusion before and after stabilization splint therapy in malocclusion group outside the normal range of CR-CO discrepancy. The normal occlusion group consisted of 80 subjects who had well-balanced faces and good occlusions with acceptable Class I molar relationship. They had not been treated orthodontic ally and had no signs or symptoms of temporomandibular joint dysfunction. 71 malocclusion patients enrolled for orthodontic treatment at the Department of Orthodontics, College of Dentistry, Chosun University comprised the malocclusion group, little variation of growth factor by the second molar eruption. They had CR-CO discrepancy beyond normal range and were subdivided into anterior-posteriorly -[25 Class I (0 or = 4), and 24 Class III (ANB < or = 0)]; vertically - [20 Normodivergentscy (30 or = 34), and 18 Hypodivergency (SNGoMe < or = 30)] ; and sexually - [26 Male and 45 Female]. For malocclusion group, stabilization splint with mutually protected type of occlusal scheme was applied for three months. Panadent articulators, Panadent condylar position indicator (CPl), and lateral headfilm were used to investigate the influence of stabilization splint on condylar position and craniofacial morphology. The results of this study were as follows: 1. The amounts of CR-CO discrepancy in normal occlusion were that the antero-posterior component (delta X) was 0.56 +/- 0.46mm (Male: 0.63 +/- 0.42rnm, Female: 0.49 +/- 0.50mm) ; the supero-inferior component (delta Y) was -0.75 +/- 0.48rnm (Male: -0.76 +/- 0.52rnm, Female: -0.73 +/- 0.43rnm) ; and the transverse component (delta Z) was -0.33 +/- 0.28mrn (Male: -0.38 +/- 0.29mm, Female: -0.31 +/- 0.27mm). 2. The condylar position was in normal range after stabilization splint therapy. 3. The mandible was always rotated infero-posteriorly after stabilization splint therapy. 4. Antero-posteriorly, Class III malocclusion responded very well to the stabilization splint therapy. 5. Vertically, Hyperdivergency responded very well to the stabilization splint therapy. 6. Sexually, Male responded very well to the stabilization splint therapy.
Centric Relation ; Dental Articulators ; Dentistry ; Female ; Humans ; Male ; Malocclusion ; Mandible ; Molar ; Orthodontics ; Reference Values ; Splints* ; Temporomandibular Joint

The purpose of this study was to evaluate the characteristics of craniofacial skeleton on orthognathic surgical cases with skeletal Class III malocclusion. For this study, 74 students at the dental college of Chosun University volunteered as a normal occlusion group. They had well-balanced faces and good occlusions with acceptable Class I molar relationship. They had not received orthodontic treatment and had no signs or symptoms of temporomandibular joint dysfunction. 45 malocclusion patients enrolled for orthognathic surgical treatment with skeletal Class III malocclusion at the Department of Orthodontics, College of Dentistry, Chosun University. On the basis of this study, the results of this study were as follows: 1. Skeletal Class III malocclusion was largely due to the overgrowth of mandible in man and the undergrowth of maxilla in woman. 2. The mandible was antero-inferiorly overgrown by large MP-HP angle and large gonial angle in orthognathic surgical cases with skeletal Class Iii malocclusion. And also, upper incisors were severely labioversioned, but on the other hand lower incisors were linguoversioned. 3. In female, lower-third facial height was characteristically shortened in comparison with middle-third facial height and also, lower facial throat angle was sgrall in male.
Dentistry ; Female ; Hand ; Humans ; Incisor ; Male ; Malocclusion* ; Mandible ; Maxilla ; Molar ; Orthodontics ; Orthognathic Surgery ; Pharynx ; Skeleton* ; Temporomandibular Joint

The purposes of this study were to evaluate and compare the frequency of ceramic bracket fracture, frequency of enamel fracture, bond fracture site, adhesive remnant index after mechanical and electrothermal debracketing, to evaluate effectiveness of high and low speed rotary instrument and ultrasonic instrument during residual adhesive remnants removal, and to measure resin film surface(percentage) using by image artalyser(Leco 300). Bond fracture site, bracket fracture, and enamel surface damage were examined by scanning electron microscope. The following results were obtained: 1. In the mechanical debracketing group, the bond failed predominantly at enamel-adhesive interface with the bulk of adhesive remaining on bracket base. 2. In the eletrothermal debracketing group, the bond failed predominantly at adhesive-bracket interface with the bulk of adhesive remaining on enamel surface. 3. The most effectiveness of residual resin removal was obtained by means of the resin polishing bur and the order of scratch formation was the precedure using tungsten carbide bur, ultrasonic scaler, sot-lex disc, and polishing bur. 4. The order of the resin film surface percentage was ultrasonic scaler, tungsten carbide bur, sot-lex disc, and resin polishing bur.
Adhesives ; Ceramics* ; Dental Enamel* ; Tungsten ; Ultrasonics

The purpose of this study was to evaluate clinical applicability of light cured glass ionomer cement as a othodontic adhesive. The metal brackets and plastic brackets were bonded with light cured glass ionomer cement(Fuji Ortho LC(R)) after polishing with a slurry of pumice, surface conditioning with 10% polyacrylic acid and chemically cured resin(Mono-Lok2(R)) after acid etching with 38% phosphoric acid on the extracted human bicuspids. The shear bond strength was tested with a universal testing machine(HGS-100A, Shimadzu Co., Japan) after storage in normal saline at 37degreesC or 24 hours and 48 hours. The results were as follows: 1. The shear bond strength of light cured glass ionomer cement group polished with a slurry of pumice was significantly lower than that of chemically cured resin group(P<0.01). 2. The shear bond strength of light cured glass ionomer cement group conditioned with 10% polyacrylic acid was significantly lower than that of chemically cured resin group(P<0.01). 3. The shear bond strength of light cued glass ionorner cement group conditioned with 10% polyacrylic acid was slightly higher than that of light cured glass ionomer cement group polished with a slurry of pumice, but there was no significant difference(P>0.05). 4. There was no significant difference between metal bracket group and plastic bracket group irrelevant off enamel conditioning(P>005). In summary, although the shear bond strength of light cured glass lionomer cement was lower than that of chemically cured resin, it night be clinically applicable.
Adhesives ; Bicuspid ; Dental Enamel ; Glass Ionomer Cements ; Glass* ; Humans ; Orthodontic Brackets* ; Plastics

This paper aimed to study what the influences of orthodontic treatment of pronunciation are. We compared the duration and the acoustic wave patterns of Korean consonants pronounced by a control group with those of a patient who had his four premolars extracted and had been given orthodontic treatment The results were as follows : 1. Compared to the control group, the treatment group had a longer duration time of consonant pronunciation for all consonants but "s " and "th" in CV(consonant-vowel) pairs. Especially in the case of "dz", "phih" for CV-pairs, and "d" in VCV(vowel-consonant-vowel) clusters, the duration of consonant sound showed a sharp contrast between the control group and the treatment group. 2. There were clear differences in the acoustic wave patterns of "ts", "phih" and "ch", all of which were in VCV-clusters. The acoustic wave pattern of "ts", when pronounced by the treatment group, was stronger than the control group's. This phenomenon was most remarkable in the transitive section where the "ts" sound flowed into the following vowel. When a preceding vowel shifted to the consonant "phih", the attack property of the appeared clearly in the acoustic waves of the t,reament group, while in the control group the starting point of consonart was indistinctive. Consonant duration for the treatment group was longer, and the appearance of a zero crossing point in the acoustic wave was more frequent. In the case of "ch", the treatment group produced a strong acoustic wave, and the property of aspiration was obvious in it 3. When the treatment group pronounced "d" and "dz" in CV-pairs, the acoustic-wave was similar to that of aspirated "th" and "ch". 4. The aspirated "th" and "ch" pronounced by the treatment group showed the stronger airstream and acoustic wave form.
Bicuspid* ; Humans ; Sound

This study was performed, by Finite Element Method, to evaluate the stress distribution on the periodontal tissue according to activation of the various closing loops and to predict the pattern of movement of maxillary incisors. At the same time, bull loop, key-hole loop, T-loop, combination loop and asymmetrical T-loop which were used for retraction of maxillary incisors was analysed by Finite Element Method. The following results were obtained. 1. Horizontal force wits the greatest in bull loop, the followed by key-hole loop, combination loop, T-loop and initial tooth movement exhibited uncontrolled tipping. 2. Horizontal force in asymmetrical T-loop compared to other closing loops was remarkably decreased, and the intrusive force on the incisors occurred. 3. As torque was increased, the moment was increased as a linear increment. 4. As moment was increased, initial movement of tooth changed to root movement from uncontrolled tipping.
Incisor* ; Tooth ; Tooth Movement ; Torque

This study was undertaken to investigate the relation between orthodontic force magnitude and the amount of tooth movement. And more light force application for reducing root resorption. Twenty-four rats were divided into three experimental groups(A, B, C) based on force magnitude and application method. Springs of 50g force were applied to A group, spring of 100g force were applied to B group and springs of 25g force were applied to C group initially, and after 4 days springs of C group were changed to springs of 50g force. Two kinds of sentalloy(R) (GAC U.S.A) closed coil spring, 50g and 100g, were used. And we made 25g springs by heat treatment process of 50g spring. Each spring was inserted between the maxillary central incisor and the maxillary left first molar. Amounts of tooth movement were measured everyday by digital caliper(Digimatic(R) , Mitutoyo, Japan) under inhalation anesthesia for 15 days, all rats were sacrificed and histological sample were obtained with Hematoxyline-Eosin stan and Masson's trichrome stain. Following conclusion were made : 1. Group B showed the mean cumulative tooth movement of 2.19+/-0.41mm at 15th day, which was greatest among three groups, followed by group C(2.06+/-0101mm), group A(1.90+/-0.49mm) respectively. However, there was no statistically difference among three groups. 2. All groups showed general tooth movement pattern and A, B, C group finished lag phase at 9th, 8th, 7th day, but three was no statistical significance. 3. Group A, B, C showed root resorption and especially group B showed the most severe root resorption and group C showed milder root resorpting than other groups. According to the above results, large initial force with the development of a fairly widespread hyalinized zone may cause severe root resorption, so initial force should be applied lightly to reduce hyalinized area and eventually root resorption and then increased force will induce efficient tooth movement.
Anesthesia, Inhalation ; Animals ; Hot Temperature ; Hyalin ; Incisor ; Molar ; Rats* ; Root Resorption* ; Tooth Movement* ; Tooth*

The purpose of this study was to identify the compensatory adaptation of dentoalveolar structure according to the various skeletal relation though the statistical correlation between the anteroposterior, vertical skeletal and dentoalveolar relation, For this study, the sample were consisted of 101 adult subjects (51male and 50 female, mean age; male 23.6 years, female 21.5 years) who had good occlusion with the range of normal overjet and overbite and acceptable Angle's class I molar relationship which had not been related orthodontically. The results were as follows : 1. Even though acceptable normal occlusion, the range of measurements which represent anteroposterior, vertical skeletal relation and dentoalveolar relation were very wide. 2. Upper and lower incisor axis were significantly correlated with anteroposterior skeletal relation, which means the more lingual inclination of upper anterior teeth and the more labial inclination of lower anterior teeth according to the more anterior position of mandible to the maxilla (p<0.01). 3. Upper and lower anterior alveolar bone height was statistically correlated with the lower anterior vertical skeletal height. 4. Upper and lower alveolar bone hight were not correlated with anteroposterior skeletal relation (p>0.05). 5. The correlation between the incisor axis and vertical skeletal was more closely related in upper anterior teeth than the lower anterior teeth. To summarize the above results, even though acceptable normal occlusion, skeletal and dentoalveolar relation was very widely ranged, and there were close relationship between the anteroposterior skeletal relation and the inclination of upper and lower anterior teeth and between the vertical skeletal relation and upper and lower anterior alveolar bone height. These finding can be concluded as compensatory adaptation to the different skeletal relationship
Adult ; Axis, Cervical Vertebra ; Female ; Humans ; Incisor ; Male ; Mandible ; Maxilla ; Molar ; Overbite ; Tooth*

Rapid palatal expansion(RPE) is a method of inducing the new bone formation in the palate by separation of the midpalatal suture, which can be done conveniently by placing heavy force across the maxillary dental arch. This experiment was undertaken to examine the histologic changes after RPE and during retention period. Four young adult dogs(a control dog, three experimental dogs) aged 4 to 6 months old were used for this experiment Expansion screw(Hyrax(R), Dentarum Inc.) was delevered to the palate and turned 180 degrees every morning and evening for 8 days, giving a total expansion of 72mm. A control dog was sacrified at the starting point of this study without any treatment and three experimental dogs were sacrified after RPE, 14-day retention, and 28-day retention in each. Thereafter, those samples were observed with hematoxylin-eosin(H-E) stain, ground section(Vrillanueva stain), alkaline phosphatase(ALP) stain, tartrate-resistant acid phosphatase(TRA) stain. The results were as followings: 1. After RPE, collagen fiber bundles were stretched along the midpalatal suture and few osteoblasts were flattenedinactive state and also, a little osteoid tissues was observed. Few multinucleated osteoclasts which had TRAPpositive activity in their cytoplasm were seen in horizontal section, whereas a few osteoclasts were seen in frontal section, especially in the nasal floor side of palatal bone. 2. After 14-day retention, collagen fiber bundles were stretched along the midpalatal suture and few osteoblasts which had ALP-positive activity in their cytoplasm were seen. Few multinucleated osteoclasts which had TRAP-positive activity in their cytoplasm were seen in horizontal section, whereas a few osteoclasts were seen in frontal section, especially in the nasal floor side of palatal bone. 3. After 28-day retention, collagen fiber bundles were arranged like those of control dog and osteoblasts which showed a lot of immature bone formation were cuboidal shape and exhibited ALP-positive activity in their cytoplasm. Few multinucleated osteoclasts which had TRAP-positive activity in their cytoplasm were seen in horizontal section, whereas a few osteoclasts were seen in frontal section, especially in the nasal floor side of palatal bone. According to the above results, the new bone formation after rapid palatal expansion was examined after 14-day retention and significantly increased. after 28-day retention.
Animals ; Collagen ; Cytoplasm ; Dental Arch ; Dogs* ; Humans ; Infant ; Osteoblasts ; Osteoclasts ; Osteogenesis ; Palate ; Sutures* ; Young Adult*

An epidemiological investigation was carried out at Yongin, Kyungkido, South Korea to determine the prevalence of symptoms of temporomandibular disorders and parafunctional habits in adolescent aged 16, 17 and 18 years. 2,098 students(male 507, female 1,591) were randomly selected and investigated with the questionnaire. The results were obtained as follows. 1. The prevalence of symptoms of temporomandibular disorders was 80.9% total, 77.3% for male and 82.0% for female with significance between male and female(P<0.05). 2. The prevalence of symptoms of temporomandibular disorders was gradually increased according to increasing age with significant difference among ages(P<0.01) 3. The most frequent symptom in the temporomandibular disorders is pain on chewing(65.9), and then clicking(50.7%), pain on mouth opening(41.8%), and pain on TMJ(36.8%). 4. There was little corelationship between clenching habits and symptoms of temporomandibular disorders(r=0.166), and also between bruxing habit and those(r=0.057).
Adolescent ; Female ; Gyeonggi-do* ; Humans ; Korea* ; Male ; Mouth ; Prevalence* ; Surveys and Questionnaires ; Temporomandibular Joint Disorders*