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 evaluate the effects of fluoride relasing orthodontic sealant on the shear bond strength of light-and chemical-cured orthodontic resins, compare the sheat bond strenth with light-and chemical-cured orthidintic resins, and to identify the changes of shear bond strength by rebonding in vito. The brackets were divided into eight groups. Each group of metal grackets had different bonding mechanisms with adhesives. Group A : Transbond only Group B : Mono-Lok2 only Group C : Light cured FluoroBond+Transbond Group D : Light cured FluoroBond+Mono-Lok 2 Group E : Transbond only(rebonded) Group F : Nomo-Lok 2 only(rebonded) Group G : Light cured FluoroBond+Transbond(rebonded) Group H : Light cured FluoroBond+Mono-Lok 2(redonded) 65 extracted human premolars were prepared for bonding and 65 metal brackets for each group were bonded to prepared enamel surfaces of buccla surfaces as the above prescription. 24 hours bonding after, the Instron universal testing machine was usedto test the shear bond strength of metal brackets to enamel. After debonding, same kind of metal brackets for each group wrer rebonded to prepared enamel surfaces of buccal surfaces to test the shear bond strength at the rebonding to enamel. Statistical analysis of data was carried out Student's t-test ANOVA test, and Scheffe test using SPSS/PC+. The results were as follows : 1. The order of bond strength was Group B(11.84MPa), Group A(10.75MPa), Group D(9.69MPa), and Group C(9.39MPa) in 1st bonded groups. 2. The order of shear bond stermgth was Group E(7.40MPa), Group G(6.48MPa), Group F(5.89MPa), and Group H(5.15MPa) in rebonded groups. 3. The shear bond strength of chemical cured orthodontic resins had higher than that of light-cured orthodontic resins in all groups, but there was no statistical significance between groups(P>0.05). 4. In rebonded groups, the shear bond strength of light cured orthodontic resins had higher than that of chemical cured orthodontic resins, but there was no statistical significance between grouops(P>0.05). 5. The shear bond strength of all rebonded groups progressively decreased than that of 1st bonded groups, and there was statistical significance between groups(P<0.05, P<0.001).
Adhesives ; Bicuspid ; Dental Enamel ; Fluorides* ; Humans ; Prescriptions

This study was done to evaluate the correlations berween the size, the form of the cranial base, head posture and the horizontal and vertical position of craniofacial structures. For this purpose, 100 cephalometric radiographs were taken from the sample composed of 51 male and 49 female, 12 measurement criteria and 37 reference points were established and digitized, then calculation was performed for the values of measurement variables and the horizontal and vertical position of reference points. The correlations between them were analyzed statistically and mean facial diagrams were constructed and compared with the selected groups which were composed of 10 Samples each as large and small group from the measurement value. The following results were obtained : 1. The angles n-s-ba and n-s-ar as variables for the form of cranial base correlated hight to the horizontal and vertical position of reference points in the cervical column with statistical significance(0.1% level). 2. The angles n-s-ba and n-s-ar as variables for the form of cranial base correlated to the horizontal position of the reference points in the facial stucture with statistical significance(1% level), but not to the vertical position of them(5% level). 3. The length n-s, s-ba, and n-ar as variables for the size of cranial base were correlated th the position of eranioracial structures in various ways, but in general, highly correlated to the horizontal and vertical position of midfacial structures around the teeth and alveolar area. 4. The angle NAL/CVT and NSL/OPT as postural variables for the inlination if cranial base and cervical column were correlated to the horizintal position of the craniofacial structures with statistical significance(1% level), but not to the vertical position of them(5% level). 5. The angle OPT/HOR and CVT/HOR as postural variables for the inclination of cranial base and ture horizontal line were not correlated to the horizintal and vertical position of the craniofacial structures with statistical significance(5% level). 6. The correlation between the measurement variables and horizontal and vertical positions of the reference poits in soft tissue were shown as similar to the related hard tissue points.
Female ; Head* ; Humans ; Male ; Posture* ; Skull Base* ; 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*