The aim of this study was to compare the species and biotypes of mutans streptococci isolated from dental plaques sampled from the interfaces between the bracket and tooth surface and smooth tooth surfaces in orthodontic patients. Dental plaque was collected from the interfaces between brackets and teeth (test group), and from smooth tooth surfaces distant from brackets by more than 2 mm (control group). The dental plaque collected by a sterilized curette was transferred into a vial of 1 X PBS. The sample in the vial was vigorously vortexed for 1 min and plated on mitis-salivarius bacitracin (MSB) agar plate using cotton tips. The agar plates were incubated at 37 degrees C in a candle jar for 2 days, and again incubated for 1 more day at anambient temperature. Individual colonies were cultured in TH broth at 37 degrees C CO2 incubator. The PCR-RFLP based on dextranase gene was performed for the identification of mutans streptococci at the species-level. For biotyping of mutans streptococci, biochemical tests were performed. There was no significant difference of the species of mutans streptococci isolated from both test and control groups. However, the biotypes of the mutans streptococci isolated from test and control groups were different. These results may offer the basic data to verify the relationship between the mutans streptococci biotype and enamel decalcification or dental caries in orthodontic patients with fixed appliances.
Agar ; Bacitracin ; Dental Caries ; Dental Enamel ; Dental Plaque* ; Dextranase ; Humans ; Incubators ; Tooth*

In this study, we attempt to investigate the mechanisms by which PDL cells regulate osteoclast formation and also to know whether PDL retained their characteristic phenotype during tooth eruption and interdental separation. Rats were prepared at developmental days 21 (pre-root formation), 27 (root development), 34 (advanced root formation/ eruption) and at later times(adult rats). To induce severe resorption state of alveolar bone and tooth root, interdental separation with brass wire was performed between the lower first and second molars for 2 weeks in adult rats. Rat mandibles were demineralized and embedded in paraffin, and horizontal and frontal section were prepared for immunohistochemical analysis using PDL-specific protein 22 (PDLs22), receptor activator of NFKB ligand (RANKL) and osteoprotegerin (OPG) antibodies. 1. Root formation and eruption stage of tooth development. 1) PDLs22 immunolocalization was observed in tooth follicle/PDL cells and osteoblasts throught out the root formation and eruption stages of tooth development. 2) RANKL expression became stronger at eruption stage than root formation stage of tooth development. 3) Strong expression of OPG was detected in follice/PDL cells of root formation stage but it was decreased with tooth eruption. 2. Interdental separation between lower first and second molar. 1) Comparared to normal animal, multinucleated osteoclasts and odontoclasts were markedly induced in the alveolar bone and tooth root with PDL remodeling in hematoxylin-eosin section. 2) PDLs22 expression was decreased with interdental separation. 3) RANKL expression was increased with interdental separation in PDL fibroblasts, osteoblasts, odontoclasts and it lacunae, resorbing dentin, cementum and bone matrix. 4) OPG expression was slightly decreased in the PDL cells adjacent to the alveolar bone and root surface with interdental separation. These results suggested that during tooth eruption and tooth movement, RANKL and OPG in the periodontal tissues are important determinants regulating balanced alveolar bone and tooth root resorption. And it is also suggested that PDL cells retained their characteristic phenotype during tooth eruption and interdental separation except for the short period of PDL remodeling.
Adult ; Animals ; Antibodies ; Bone Matrix ; Dental Cementum ; Dentin ; Fibroblasts ; Humans ; Mandible ; Molar ; Osteoblasts ; Osteoclasts ; Osteoprotegerin ; Paraffin ; Periodontal Ligament* ; Phenotype ; Rats* ; Tooth Eruption* ; Tooth Movement ; Tooth Root ; Tooth*

As a research method that weighs and combines evidence, meta analysis produces evidence that is more powerful than the original studies. The purpose of this study was to compare the intercanine/intermolar expansion and rapid/slow expansion in the maxillary expansion treatment using meta analysis. Medline was searched from 1979 to 2000 for all studies examining the stability of transverse expansion of the human maxilla, and 388 articles were found. Then these articles were reduced to 7 based on the defined inclusion and exclusion criteria, and a cumulative Meta evaluation score was computed for each study. The results were as follows; 1. The mean expansion in intermolar width was 6.0mm. Of the 6.0mm, 4.8mm was retained and 20.0%(1.2mm) was relapsed while wearing retainers. 2. In intercanines width, the mean expansion was 3.7mm. Of the 3.7mm, 2.6mm was retained and 29.7%(1.1mm) was relapsed while wearing retainers. 3. The differences in the amount of expansion and relapse between rapid expansion group and slow expansion group were less than 6%(0.1-0.3mm). But, there might be differences in the skeletal/dental exapnsion ratios according to the expansion method.
Humans ; Maxilla ; Palatal Expansion Technique* ; Recurrence

It has not been elucidated whether the initiation of condylar development of the mandible is related with the periosteum of the mandible, or if it derives from a separate programmed blastema not related with the mandible. Also, although the mandibular condylar cartilage is known to promote growth, few studies have dealt with molecular-biologic mechanisms such as the expression of specific genes according to the differentiation of the mandibular condyle. To elucidate the unique cellular characteristics, development, and differentiation process of the mandibular condyle, an examination of expressions of genes characteristic of cartilage and bone were carried out using RT-PCR and mRNA in situ hybridization. 1. Type?collagen mRNA was detected with type II collagen mRNA in the differentiation and growth process of the cartilage of the mandibular condyle. Type II collagen mRNA was demonstrated in the whole resting and upper part of the proliferative zone, whereas type II collgen mRNA was observed in the resting, proliferative and upper hypertrophic cartilage zone of the mandibular condyle. 2. The condylar cartilage rapidly increased in size due to the accumulation of hypertrophic chondrocytes as characterized by the expression of type II collagen mRNA during postnatal development. 3. BMP-4 mRNA was present in the anlage of the future condylar process and also in the ossifying mandibular body. 4. IHH mRNA was limited exclusively to the lower part of the proliferative zone and the upper part of the hypertrophic cartilage zone during condylar development. These findings were different from those in the growth-plate cartilage of the long bone, indicating a characteristic feature of the differentiation of the chondrocytes in the condylar cartilage present in prenatal and postnatal development. Furthermore, it was also suggested that chondroblasts of condylar cartilage rapidly differentiate into hypertrophic chondrocytes with increased functional Load force such as muscle activity and mastication.
Animals ; Cartilage* ; Chondrocytes ; Collagen ; Collagen Type II ; In Situ Hybridization ; Mandible ; Mandibular Condyle* ; Mastication ; Mice* ; Periosteum ; RNA, Messenger*

Mutans streptococci is the major causative factor in dental caries. Especially, orthodontic patients with fixed appliance are a risk group for dental caries. Because fixed appliances attached on teeth may change the environment of dental plaque, the enamel decalcification or dental caries around the bracket and band is a major side effect of orthodontic treatment. The aim of this study was to search plant extracts that have antimicrobial effect on mutans streptococci. Seed-extract of Casia tora were prepared with ethanol and CHMC-2032, the leaf-extracts from Camellia sinensis extract, was obtained extract, 2 type strains and 20 clinical isolates of mutans streptococci isolated from the interface between orthodontic brackets and tooth surfaces in the orthodontic patients were used in this study. The minimal inhibitory concentration of CHMC-2032 was 5 mg/ml on the S. mutans KCTC 3065, S. sobrinus KCTC 3088, and 8 clinical isolates of S. sobrinus. However, there was no antibacterial effect of seed-extract of C. tora on mutans streptococci. These data suggest that green tea may be more effective than the tea prepared from C. tora in the prevention of enamel decalcification or dental caries around brackets.
Camellia sinensis* ; Camellia* ; Dental Caries ; Dental Enamel ; Dental Plaque ; Ethanol ; Humans ; Orthodontic Brackets* ; Plant Extracts ; Tea ; Tooth*

The purpose of this study was to evaluate the material for fixed type retainer, allowing physiologic tooth movement. and proper remodeling of periodontal tissue during retention period. The present study was performed to observe the histologic changes of periodontal tissue after application of different types of fixed type retainer after orthodontic tooth movement in young adult dogs. For this study, 4 young adult dogs were used as a experimental animal and experimental group was divided into three groups ; experimental group 1 contained right side maxillary third incisors and canines, experimental group 2 contained contralateral teeth of same animals, and control group contained mandibular premolars. And each dogs were applied the 4 different types of fixed type retainer to experimental group 1. The experimental teeth were ligated on the Sentalloy closed coil spring(R)(Tomy Co., Japan) from maxillary third incisors and canines and applied orthodontic force at initial 200gm-forced during 1 week. All the experimental animals were sacrificed on the 3rd week after the orthodontic teeth movement and then the specimens were taken, fixed in formalin, embeded in parafin, sectioned 6-8micrometer in thickness and stained with Hematoxylin-Eosin staining, and Masson's trichrome staining method. Examined under the light microscopy. The following results were observed. 1. There were observed that decreased infiltration of giant cells in pressure side and increased the new bone forming in tension side on the specimen of 6-stranded 0.0195' Respond(R)(G&H Co., U.S.A.) group. Periodontal ligament fibers were much compressed or elongated in 3-stranded 0.018', 0.020' Dentaflex(R)(Dentarum Co., Germany), and Superbond C&B(R)(Sun Medical Co., Japan) groups. 2. In experimental group 1, necrotic bone inside the alveolar bone of pressure side, forming of the sharpey's fiber in osteoid tissue, and remodeling of the periodontal ligament were observed in all animals. 3. In experimental group 2, it was observed that the amount of bone resorption was equal or decreased in pressure side, and increased new bone forming and significantly decreased infiltration of giant cell than the experimental group 1. By this results, it considered that 6-stranded Respond(R)(G&H Co., U.S.A.) wire was the most useful material allowing early periodontal tissue remodeling.
Animals ; Bicuspid ; Bone Resorption ; Dogs* ; Formaldehyde ; Giant Cells ; Humans ; Incisor ; Microscopy ; Periodontal Ligament ; Tooth ; Tooth Movement ; Young Adult*

This study was undertaken to demonstrate the forces in the maxillary alveolar bone generated by the activation of the maxillary posterior crossbite appliance in the treatment of posterior buccal crossbite caused by buccal ectopic eruption of the maxillary second molar. A photoelastic model was fabricated using a photoelastic material ( PL-3 ) to simulate alveolar bone and ivory-colored resin teeth. The model was observed throughout the anterior and posterior view in a circular polariscope and recorded photographically before and after activation of the maxillary posterior crossbite appliance. The following conclusions were reached from this investigation : 1. When the traction force was applied on the palatal surface of the second molar, stresses were concentrated at the buccal and palatal root apices and alveolar crest area. The axis of rotation of palatal root was at the root apex and that of the buccal root was at the root 1/4 area. In this result, palatal tipping and rotating force were generated. 2. When the traction force was applied on the buccal surface of the second molar, more stresses than loading on the palatal surface were observed in the palatal and buccal root apices. Furthermore, the heavier stresses creating an intrusive force and controlled tipping force were recorded below the buccal and palatal root apices below the palatal root surface. In addition, the axis of rotation of palatal root disappeared whereas the rotation axis of the buccal root moved to the root apex from the apical 1/4 area. 3. When the traction force was simultaneously applied on the maxillary right and left second molars, the stress intensity around the maxillary first molar root area was greater than the stress generated by the only buccal traction of the maxillary right or left second molar. As in above mentioned results, we should realize that force application on the palatal surface of second molars with the maxillary posterior crossbite appliance produced rotation of the second molar and palatal traction, which may cause occlusal interference. That is to say, we have to escape the rotation and uncontrolled tipping creating occlusal interference when correcting buccal posterior crossbite. For this purpose, we recommend buccal traction rather than palatal traction force on the second molar.
Axis, Cervical Vertebra ; Malocclusion* ; Molar ; Tooth ; Traction ; United Nations

This study was undertaken to demonstrate the forces in the mandibular alveolar bone generated by activation of the mandibular posterior crossbite appliance in the treatment of buccal crossbite caused by lingual eruption of mandibular second molar. A three-dimensional photoelastic model was fabricated using a photoelastic material ( PL-3 ) to simulate alveolar bone. We observed the model from the anterior to the posterior view in a circular polariscope and recorded photographically before and after activation of the mandibular posterior crossbite appliance. The following results were obtained : 1. When the traction force was applied on the buccal surface of the mandibular second molar, stress was concentrated at the lingual alveolar crest and root apex area. The axis of rotation also was at the middle third of the buccal root surface and the root apex, so that uncontrolled tipping and a buccal traction force for the mandibular second molar were developed. 2. When the traction force was applied on the lingual surface of the mandibular second molar, more stress was observed as opposed to those situations in which the force application was on the buccal surface. In addition, stress intensity was increased below the root areas and the axis of rotation of the mandibular second molar was lost. In result, controlled tipping and intrusive tooth movements were developed. 3. When the traction force was applied on either buccal or lingual surface of the second molar, the color patterns of the anchorage unit were similar to the initial color pattern of that before the force application. So we can use the lingual arch for effective anchorage in correcting the posterior buccal crossbite. As in above mentioned results, we must avoid the rotation and uncontrolled tipping, creating occlusal interference of the malpositioned mandibular second molar when correcting posterior buccal crossbite. For this purpose, we recommend the lingual traction force on the second molar as opposed to the buccal traction.
Axis, Cervical Vertebra ; Malocclusion* ; Molar ; Tooth Movement ; Traction

The segmented TMA T-loop spring, used for reciprocal space closure and described by Burstone, was used to achievebodily movement of canine. Photoelastic analysis is a technique for the transformation of internal stress into visible light patterns. The two-dimensional photoelastic stress analysis was performed, and stress distribution was recorded by photography. The purpose of this study was to visualize photoelastically the distribution of forces transmitted to the alveolus and surrounding structures using new segmented TMA T-loop spring for canine retraction. The results were as follows: 1. Decreased activation produced decreased stress of upper 1st. premolar extraction site and increased intrusive stress of upper 1st. molar, regardless of T-loop position. 2. At 5mm activation, More posterior positioning of T-loop produced an increased stress in upper 1st. premolar extraction site. 3. At 3mm activation, More posterior positioning of T-loop produced an increased stress in upper 1st. premolar extraction site and mesial lower half of upper 1st. molar mesio-buccal root. 4. At 1mm activation, More anterior positioning of T-loop produced an increased stress in upper mesial and blew apex area of upper canine root. 5. 0.25 B/L ratio and 3mm activation produced bodily movement of canine. To summarize, desired tooth movement and anchorage requirement is possible by altering the activation and mesio-distal position of the T-loop spring.
Bicuspid ; Light ; Molar ; Photography ; Tooth Movement

With socioeconomic development and change of esthetic recognition, the demand for orthodontic treatment and number of orthodontic patients has been increasing so rapidly. And frequency of malocclusion was changed. So this study was done in an attempt to provide an epidemiologic study so that we can accomodate their orthodontic needs adequately and to obtain the reliable quantitative information regarding the characteristics of orthodontic patients. Distribution and trends were examined in 3,070 malocclusion patients who had been examined and diagnosed at Department of Orthodontics, Dental Hospital, Chosun University over 10 year-period from 1990 to 1999. The results were as follows : 1.The number of patients per year was increasing trend and higher visiting rate in female(56.5%) than in male(43.5%). 2.Age distribution had shown 7~12 year-old group being the largest(37.9%) and each percentage of 13~18, 19~24, above-19, 0~6 year-old group was 32.0%, 19.6%, 7.1%, 3.4%. 3. Hellman dental age IVa which is completion of the permanent dentition showed the highest percentage in male and female. 4.Geographic distribution showed a majority of patients in Kwang Ju(71.0%). Group within the distance 10km from Chosun Dental Hospital was 56.3% and group within 20km was 14.7%. 5.Anterior cross bite showed the highest percentage in chief complaints and percentage of Mn. prognathism and protrusion of Mx. teeth was 12.6%, 12.2%. 6.Distribution in the types of malocclusion according to the Angle's classification had shown; 38.9% for Class I, 20.7% for Class II division 1, 2.0% for Class II division 2, 38.4% for Class III. 7.In the dental vertical dysplasia according to the Angle's classification, deep bite was the most frequent in Class II div.1 and div. 2(24.3%, 56.7%) and open bite in Class III(21.4%). 8.In the skeletal sagittal dysplasia, 39.3% of skeletal ClassII was due to the undergrowth of the mandible and 46.3% of skeletal ClassIII was due to the overgrowth of the mandible. 9.Distribution in orthodontic treatment accoding to the extraction and nonextraction had shown 66.9% for nonextraction case, 33.1% for extraction case, and four first bicuspids have been extracted in the highest percentage(38.6%). 10.Patients who had orthognathic surgery comprised 7.9%, with an increasing trend.
Bicuspid ; Dentition, Permanent ; Epidemiologic Studies* ; Female ; Humans ; Male ; Malocclusion ; Mandible ; Open Bite ; Orthodontics* ; Orthognathic Surgery ; Overbite ; Prognathism ; Tooth