Evaluation of cytotoxicity of electroplated stainless steel orthodontic wire / 대한치과교정학회지

The purpose of this study was to examine the cytotoxicity of orthodontic wire which had an increased diameter through electroplating, and to evaluate its possible clinical applications. First, nickel plating was carried out on the commercially available stainless steel wire using an electroplating technique. For the comparison of the electroplated wire with ready made stainless steel wire and titanium or copper, each wire was incubated for 72 hours in a medium. The release of the metal ion was measured using ICP-AES (Inductively Coupled Plasma Atomic Emission Spectrophotometer). Balb/c 3T3 mouse fibroblast was put on a microplate and placed in an incubated medium of 75%, 50%, and 20% dilation. An MTT analysis was used to compare with the medium only. The change in absorbency value of each wire group and the difference of absorbency value according to the change of dilution was measured. The results of ICP-AES analysis showed that great amount nickel ion was isolated from electroplated orthodontic wires and great amount copper ion was isolated from copper. The results of the MTT analysis showed that there was no difference in the absorbency value of titanium at any dilution. However, the electroplated wires (p < 0.001), the stainless steel wires (p < 0.05) and the copper (p < 0.001) were statistically significantly lower than those of medium only at all dilutions. Assessment as per ISO 10993, part 5, showed that electroplated wire was alloted to "moderate cytotoxic", the titanium and stainless steel wire were "non-cytotoxic". The results of this study indicate that the electroplated orthodontic wires need additional efforts to decrease cytotoxicity for their clinical applications.

Studies of Relationship between P-A Cephalometric Measurements and Vidual Facial Asymmetry / 체질인류학회지

The degree of facial asymmetry in P -A cephalogram may differ from that we felt in clinical examination. The purpose of this study was to find out the P -A cephalometric measurements affecting the visual facial asymmetry. Fifty four adult patients who had been diagnosed as the facial asymmetry in clinical examination were selected for this study. Through the analysis of facial photograph and P -A cephalogram, the following results were obtained: 1. In linear measurements, Me (Menton) to MSR (Mid -sagittal reference line), Cd (Condylion) to Me, Ag (Antegonion) to Me, and Ag to MSR were significantly related with facial asymmetric index. 2. In angular measurements, angle Cg -Me plane to MSR, angle ANS -Me plane to MSR, and angle Cd - Ag -Me were significantly related with facial asymmetric index. Especially, angle Cg -Me plane to MSR, angle ANS -Me plane to MSR were highly related. 3. In surface measurements, Cg -Ag -Ag ' and Cd -Ag -Me -Cd ' were significantly related with facial asymmetric index. The results of this study suggested that menton point was the most affected landmark in visual facial asymmetry.

The Perception of Facial Profile in Korean / 체질인류학회지

This study was performed to compare the attractiveness of facial profile among the patients, parents and orthodontists. Six untreated patients between the ages 15 ~25 with Angle 's Class I, Class II, Class III malocclusion were chosen from the Chonnam National University hospital orthodontic department. The images were altered with of the computer to simulate varying degrees of mandibular retrusion and protrusion. The results of this study were obtained as follows: 1. No significant differences in attractiveness of facial profile among the patients, parents and orthodontists. 2. More protrusive lip position was preferred in female than male. 3. More protrusive chin was preferred in orthodontist group than patients, and parents, but there were no significant differences.

The size of upper airway of the snorer in upright and supine position / 대한치과교정학회지

The purpose of this study was to compare and evaluate the upper airway structure between the snorers and asymptomatic control subjects depending on the positional change. Lateral cephalograms in the upright and supine position were taken in 25 female snorers and 20 female asymptomatic control subjects, The length and the area of the soft palate, tongue and airway were measured and evaluated statistically. The results obtained were as follows : 1. The snorers showed longer and higher tongue, narrower and longer airway, inferiorly positioned hyoid bone, longer and broader soft palate and narrower hypopharynx than the control subjects both in the upright and supine position. In addition, the snorers showed broader tongue area and narrower oropharynx area than the control subjects in supine position. 2. Depending on the positional change from upright to supine position, the controls and the snorers showed decreased airway length and superior positioned the hyoid bone. In addition, the snorers showed decreased tongue length and height, airway length and thickness and oropharynx area, but increased tongue area and soft palate area.