Analysis of midpalatal miniscrew-assisted maxillary molar distalization patterns with simultaneous use of fixed appliances: A preliminary study / 대한치과교정학회지

Skeletal anchorage-assisted upper molar distalization has become one of the standard treatment modalities for the correction of Class II malocclusion. The purpose of this study was to analyze maxillary molar movement patterns according to appliance design, with the simultaneous use of buccal fixed orthodontic appliances. The authors devised two distinct types of midpalatal miniscrew-assisted maxillary molar distalizers, a lingual arch type and a pendulum type. Fourteen patients treated with one of the two types of distalizers were enrolled in the study, and the patterns of tooth movement associated with each type were compared. Pre- and post-treatment lateral cephalograms were analyzed. The lingual arch type was associated with relatively bodily upper molar distalization, while the pendulum type was associated with distal tipping with intrusion of the upper molar. Clinicians should be aware of the expected tooth movement associated with each appliance design. Further well designed studies with larger sample sizes are required.

Menarcheal timing and growth curve shape during the adolescent growth spurt / 대한치과교정학회지

OBJECTIVE: This study investigated the onset, peak height velocity (PHV) and end of adolescent growth spurt as well as menarcheal timing deduced from surveying accumulative height growth over many years. METHODS: Ninety six students of Samgoe high school between 1st and 3rd grade that were in good health participated in the research. A survey questionnaire was distributed to examine the students' health status and menarche timing. RESULTS: Adolescent growth spurt typically began at the age of 9.9 and reached a PHV at the age of 11.6. The growth spurt ended at the age of 14.1 on average. The average age of menarche was 12.6 years, which was about one year after the PHV of adolescent growth spurt. In most cases, menarche came after PHV. But in 24% of the students, menarche and PHV was nearly coincident or menarche preceded PHV. The growth curves were classified into four types. A typical adolescent growth spurt showed one PHV on graph that drastically drops after the PHV. However, there were cases with two PHVs. CONCLUSIONS: The results indicate that individual growth patterns show large individual differences, however the categorization into the various growth curves may aid in predicting individual growth patterns.

Maturation of cervical vertebrae in relation to menarche / 대한치과교정학회지

OBJECTIVE: The purpose of this study was to investigate the relationship between menarche and cervical vertebral maturation. METHODS: Lateral cephalograms of 67 young korean girls within the range of 1 year before or after their menarche were gathered. The concavity of the cervical vertebrae base and the ratio of the base length to the 3rd and 4th cervical vertebrae anterior height were measured and analyzed. RESULTS: The mean measured values were as follows; concavity of the 3rd cervical vertebrae base: 1.27 (+/- 0.18) mm, concavity of the 4th cervical vertebrae base: 1.06 (+/- 0.15) mm, ratio of the base length to the 3rd cervical vertebrae anterior height: 0.73 (+/- 0.06) and ratio of the base length to the 4th cervical vertebrae anterior height: 0.70 (+/- 0.05). There was a significant increase in the ratio of the base length to the 3rd vertebrae anterior height and the base concavity of the 3rd and 4th cervical vertebrae during the period of 1 year before to 1 year after their menarche. CONCLUSIONS: These characteristics of the 3rd and 4th cervical vertebrae on the lateral cephalogram can provide useful clues on evaluating the growth stage.

The effect of indomethacin on the matrix metalloproteinases in canine permanent tooth eruption / 대한치과교정학회지

Tooth eruption requires remodeling of surrounding tissues. This study was aimed to investigate the effect of indomethacin on the dental follicle and paradental tissues during tooth eruption by observing the distribution and expression of MMP by the immunohistochemical method. Ten mongrel dogs of ten to twelve weeks old were divided into 5 groups; four experimental groups administered indomethacin 2 mg/Kg/day and 8 mg/Kg/day orally 2 times a day for 14 days and 7 days respectively, and the control group was administered a placebo. Permanent teeth before eruption and their surrounding tissues were selected and excised. H and E staining and immunohistochemical stainings of MMP-3 and -9 were performed and examined under the light microscope. Osteoclasts, osteoblasts, periodontal ligament cells, ameloblasts and odontoblasts of the control group all expressed MMP-3 and -9. In the experimental group, osteoclasts, osteoblasts and periodontal ligament cells showed reduced expression of MMP-3 and -9. Magnitude of MMP reduction in the experimental group showed a time and dose of indomethacin administration dependent manner. These results show that indomethacin inhibited MMP-3 and -9 expression in the dental follicle and surrounding tissues and suggest that when indomethacin is administered for long periods, tooth eruption could be delayed.

The effects of indomethacin on distribution and expression of COX-2 and IGF-I in the mandibular condyle of growing dogs / 대한치과교정학회지

This study aimed to investigate the effects of indomethacin on distribution and expression of COX-2 and IGF-I in the mandibular condyle of growing dogs and to examine the number of chondroclasts around the mineralization zone. Indomethacin inhibits prostaglandin E2 production in the tissue by inhibiting synthesis of cyclooxygenase 2. Prostaglandin E2 stimulates insulin-like growth factor synthesis. Insulin-like growth factor stimulates growth of mandibular condylar cartilage. Eight mongrel dogs, aged 13 - 14 weeks, were divided into 4 groups. Group 1 and group 2 were administered indomethacin 2 mg/Kg/day orally two times a day for 7 days and 14 days respectively. Group 3 were administered indomethacin 8 mg/Kg/day orally 2 times a day for 14 days, and the control group were administered a placebo. The mandibular condyle heads were sectioned in 5 micrometer thickness. The specimens were stained with H-E staining, COX-2 immunohistochemical staining and IGF-I immunohistochemical staining and examined under light microscope. After TRAP staining, the number of chondroclasts were calculated. The observed results were as follows: Indomethacin inhibited expression and distribution of COX-2 and IGF-I on the proliferative zone of condylar cartilage. Indomethacin decreased the number of chondroclastes on the mineralization zone by a time-dependent manner (p < 0.05). Indomethacin inhibited expression and distribution of IGF-I by a dose- and time-dependent manner. These results show that indomethacin inhibited expression and distribution of COX-2 and IGF-I on the proliferative zone of condylar cartilage and decreased the number of chondroclasts and suggests that when indomethacin is administered for a long time, condyle growth could be delayed.

A study of mandibular dental arch form of the Korean with normal occlusion / 대한치과교정학회지

The purpose of this study was to classify mandibular dental arch forms based on Raberin's method, and to compare Raberin's arch forms with that of the Korean's, and to designate arch form of bracket level according to distance between cusp tip and buccal surface of bracket level. The sample consisted of 159 mandibular dental casts showing normal occlusion which was taken from 62 males and 97 females of the Korean, aging from 13 to 25 years. The model was taken by X-ray. The landmarks were cusp points which expressed the mandibular dental arch line of cusp tips and buccal points which were measured from cusp tips to buccal surfaces of bracket level. The landmarks on the film were digitized, and measurements and statistics were performed. The results were as follows; 1. The models were classified as type I, type 2, type 3, type 4 and type 5 by the author, and polynomial functions of the six degree and R-square values were calculated using statistical method, and each calculated equations explained each group with the least R-square value of 0.97, and each arch forms were plotted. 2. The distribution of type I was 17.6 %, type 2 20.8%, type 3 20.8%, type 4 16.3% and type 5 24.5%. 3. The Korean arch form was characterized by larger width, smaller height compared to the French arch form. 4. The designated arch form of bracket level, viz the distance between cusp point and buccal point was calculated. The distance between cusp point and buccal point of incisor was 1mm, canine 1.9mm, first premolar 2.5mm, second premolar 2.6mm, first molar 2.7mm and second molar 2.7mm.