OBJECTIVE: We estimated the number of Korean adults with back pain and evaluated population-based associated factors of back pain from a representative sample data from the Fourth Korea National Health and Nutrition Examination Survey. METHODS: The number of Korean adults who experienced back pain (experienced patients), those who experienced back pain lasting for three or more months during the past year (chronic patients), and those who were currently suffering from back pain (current patients) were estimated by analyzing the data from the fourth Korea National Health and Nutrition Examination Survey conducted in 2007 using surveyfreq procedure of the SAS statistical package. Population-based odds ratios for being experienced, chronic, and current patient according to demographic (age and gender), socioeconomic (education and occupation), and lifestyle factors (smoking, drinking, and exercise) were estimated using surveylogistic procedure. RESULTS: It was estimated that there were 5,554,256 (proportion, 15.4%; 95% CI, 4,809,466 - 6,299,046) experienced patients, 2,060,829 (5.7%; 1,557,413-2,564,246) chronic patients, and 3,084,188 (8.5%; 2,600,197 - 3,568,179) current patients among 36,107,225 Korean adults aged 20-89 years in 2007. Each of explanatory variables was significantly associated with at least one of the response variables for back pain. CONCLUSION: Based on our study results, further efforts to investigate epidemiology of back pain, to evaluate associated factors, and to improve treatment outcomes are needed.
Adult ; Aged ; Back Pain ; Drinking ; Humans ; Korea ; Life Style ; Nutrition Surveys ; Odds Ratio ; Phenothiazines ; Stress, Psychological ; Surveys and Questionnaires

No abstract available.

OBJECTIVE: This in vitro study was undertaken to evaluate the physical, chemical, and biological properties of commercially available metal orthodontic brackets in South Korea, because national standards for these products are lacking. METHODS: Four bracket brands were tested for dimensional accuracy, (manufacturing errors in angulation and torque), cytotoxicity, composition, elution, and corrosion: Archist (Daeseung Medical), Victory (3M Unitek), Kosaka (Tomy), and Confidence (Shinye Odontology Materials). RESULTS: The tested rackets showed no significant differences in manufacturing errors in angulation, but Confidence brackets showed a significant difference in manufacturing errors in torque. None of the brackets were cytotoxic to mouse fibroblasts. The metal ion components did not show a regular increasing or decreasing trend of elution over time, but the volume of the total eluted metal ions increased: Archist brackets had the maximal Cr elution and Confidence brackets appeared to have the largest volume of total eluted metal ions because of excessive Ni elution. Confidence brackets showed the lowest corrosion resistance during potentiodynamic polarization. CONCLUSIONS: The results of this study could potentially be applied in establishing national standards for metal orthodontic brackets and in evaluating commercially available products.
Animals ; Corrosion ; Fibroblasts ; Ions ; Mice ; Orthodontic Brackets ; Republic of Korea ; Torque

OBJECTIVE: Recently, microdissection of tissue sections has been used increasingly for the isolation of morphologically identified homogeneous cell populations, thus overcoming the obstacle of tissue complexity for the analysis cell-specific expression of macromolecules. The aim of the present study was to establish the minimal conditions required for the RNA extraction and amplification from the cells captured by the laser captured microdissection. METHODS: Mouse ovaries were fixed and cut into serial sections (7 micrometer thickness). Oocytes were captured by laser captured microdissection (LCM) method by using PixCell IITM system. The frozen sections were fixed in 70% ethanol and stained with hematoxylin and eosin, while the paraffin sections were stained with Multiple stain. Sections were dehydrated in graded alcohols followed by xylene and air-dried for 20 min prior to LCM. All reactions were performed in ribonuclease free solutions to prevent RNA degradation. After LCM, total RNA extraction from the captured oocytes was performed using the guanidinium isothiocyanate (GITC) solution, and subsequently evaluated by reverse transcriptase -polymerase chain reaction (RT-PCR) for glyceraldehyde-3-phosphate-dehydrogenase (GAPDH). RESULTS: With the frozen sections, detection of the GAPDH mRNA expression in the number of captured 25 oocytes were not repeatable, but the expression was always detectable from 50 oocytes. With 25 oocytes, at least 27 PCR cycles were required, whereas with 50 oocytes, 21 cycles were enough to detect GAPDH expression. Amount of the primary cDNA required for RT-PCR was reduced down to at least 0.25 microl with 50 oocytes, thus the resting 19.75 microl cDNA can be used for the testing other interested gene expression. Tissue-to-slide, tissue-to-tissue forces were very high in the paraffin sections, thus the greater number of cell procurement was required than the frozen sections. CONCLUSION: We have described a method for analyzing gene expression at the RNA level with the homogeneously microdissected cells from the small amount of tissues with complexity. We found that LCM coupled with RT-PCR could detect housekeeping gene expression in 50 oocytes captured. This technique can be easily applied for the study of gene expression with the small amount of tissues.
Alcohols ; Animals ; DNA, Complementary ; Eosine Yellowish-(YS) ; Ethanol ; Female ; Frozen Sections ; Gene Expression* ; Genes, Essential ; Guanidine ; Hematoxylin ; Mice ; Microdissection* ; Oocytes* ; Ovary ; Paraffin ; Polymerase Chain Reaction ; Ribonucleases ; RNA Stability ; RNA* ; RNA, Messenger ; RNA-Directed DNA Polymerase ; Xylenes

OBJECTIVE: The purpose of this study was to measure the insertion torque of orthodontic miniscrews regarding changes in their shape, diameter, and length. METHODS: Torque values were measured during continuous insertion of the miniscrews into solid rigid polyurethane foam, using a torque tester of driving motor type with a regular speed of 3 rpm. Orthodontic miniscrews (Biomaterials Korea, Seoul, Korea) of cylindrical type and taper type were used. RESULTS: Increasing the length and diameter of the miniscrews increased the maximum insertion torque value in both cylindrical and taper type screws. Insertion torque was increased at the incomplete head of the cylindrical type screw, and at the tapered part of the taper type screw. The insertion torque value of miniscrews was influenced most by diameter, then shape and length. As a result, it was shown that the diameter of the screw had the most influence on insertion torque, and the taper type screw had a higher torque value than the cylindrical type screw. CONCLUSION: Therefore, a large diameter or taper type screw are adequate for areas of thin cortical bone with a large interdental space, and a small diameter or cylindrical type screw are adequate in the mandibular molar area or the midpalatal area having thick cortical bone.
Head ; Korea ; Molar ; Polyurethanes ; Seoul ; Torque*

OBJECTIVE: This study was designed to analyze the primary and secondary stability characteristics of orthodontic mini-screws of tapered design when compared with the cylinder mini-screw. METHODS: A total of 48 mini-screws were placed into the buccal alveolar bone of the mandible in 6 male beagle dogs. Comparison was made between tapered and cylinder type mini-screws (Biomaterials Korea, Seoul, Korea). Maximum insertion torque (MIT) was measured using a torque sensor (Mark-10, MGT 50, USA) during installation, and maximum removal torque (MRT) was recorded after 3 and 12 weeks of loading. RESULTS: Taper mini-screws showed a higher MIT value of 22.3 Ncm compared with cylinder mini-screw showing 13.6 Ncm (p < 0.001). The MRT of the taper mini-screw showed a significantly higher value of 9.1 Ncm than those of cylinder mini-screw of 5.7 Ncm at 3-weeks after installation (p < 0.05). However, there was no difference in the MRT value between the taper and cylinder mini-screws at 12 weeks of loading. CONCLUSIONS: These results showed that the high insertion torque of the taper mini-screw design increases initial stability until 3 weeks of loading, but does not have any effect on the secondary stability at 12 weeks of loading.
Animals ; Dogs ; Humans ; Korea ; Male ; Mandible ; Torque

OBJECTIVE: The aim of this study was to conduct three-dimensional finite element analysis of individual tooth displacement and stress distribution when a posterior retraction force of 200 g was applied at different positions of the retraction hook on the transpalatal arch (TPA) of a molar, and over different lengths of the lever arm on the maxillary anterior teeth in lingual orthodontics. METHODS: A three-dimensional finite element model, including the entire upper dentition, periodontal ligaments, and alveolar bones, was constructed on the basis of a sample (Nissan Dental Product, Kyoto, Japan) survey of Asian adults. Individual movement of the incisal edge and root apex was estimated along the x-, y-, and z-coordinates to analyze tooth displacement and von Mises stress distribution. RESULTS: When the length of the lever arm was 15 mm and 20 mm, the incisal edge and root apex of the anterior teeth was displaced lingually, with a maximum lingual displacement at the lever arm length of 20 mm. When the posterior retraction hook was on the root apex, the molars showed distal displacement. When the length of the lever arm was 20 mm, anterior extrusion was reduced and the crown of the canine displaced toward the buccal side, in which case, the retraction hook was on the edge, rather than at the center, of the TPA. CONCLUSIONS: The results of the analysis showed that when 6 anterior teeth were retracted posteriorly, lateral displacement of the canine and lingual displacement of the incisal edge and root apex of the anterior teeth occur without the extrusion of the anterior segment when the length of the lever arm is longer, and the posterior retraction hook is in the midpalatal area.
Adult ; Arm ; Asian Continental Ancestry Group ; Crowns ; Dentition ; Displacement (Psychology) ; Finite Element Analysis ; Humans ; Mechanics ; Molar ; Periodontal Ligament ; Tooth

Condylar hyperplasia is a pathologic condition showing 3-dimensional skeletal hyperplasia of the mandible. The reason for condylar hyperplasia is not yet known, but the effects of hormone, trauma, infection, genetics, fetal condition, and hypervascularity are known as possible reasons. When we diagnose a patient as having condylar hyperplasia, it is important to decide if it is in progress or not. Treatment for facial asymmetry due to condylar hyperplasia are decided accordingly, including condylectomy, that is removal of growth site of the affected condyle, and conventional orthognathic surgery only or condylectomy with orthognathic surgery after the completion of growth. Therefore, it is important to determine the growth state of condylar hyperplasia in treatment stability. This is verified through bone scan and regular check-ups with 3D CT or PA cephalogram. This case report introduces an improved case of facial asymmetry with condylectomy together with orthognathic surgery.
Facial Asymmetry ; Humans ; Hyperplasia ; Mandible ; Orthognathic Surgery

OBJECTIVE: This study was conducted to perform histomorphometric evaluations of the bone surrounding orthodontic miniscrews according to their proximity to the adjacent tooth roots in the posterior mandible of beagle dogs. METHODS: Four male beagle dogs were used for this study. Six orthodontic miniscrews were placed in the interradicular spaces in the posterior mandible of each dog (n = 24). The implanted miniscrews were classified into no loading, immediate loading, and delayed loading groups according to the loading time. At 6 weeks after screw placement, the animals were sacrificed, and tissue blocks including the miniscrews were harvested for histological examinations. After analysis of the histological sections, the miniscrews were categorized into three additional groups according to the root proximity: high root proximity, low root proximity, and safe distance groups. Differences in the bone–implant contact (BIC, %) among the root proximity groups and loading time groups were determined using statistical analyses. RESULTS: No BIC was observed within the bundle bone invaded by the miniscrew threads. Narrowing of the periodontal ligament space was observed in cases where the miniscrew threads touched the bundle bone. BIC (%) was significantly lower in the high root proximity group than in the low root proximity and safe distance groups. However, BIC (%) showed no significant differences among the loading time groups. CONCLUSIONS: Regardless of the loading time, the stability of an orthodontic miniscrew is decreased if it is in contact with the bundle bone as well as the adjacent tooth root.
Animals ; Dogs ; Humans ; Male ; Mandible ; Periodontal Ligament ; Tooth Root

No abstract available.
Aged* ; Humans