• Journal of the korean academy of Pediatric Dentistry
• /
• v.41 no.1
• /
• pp.1-7
• /
• 2014

If it is possible to preserve and culture cells from exfoliated deciduous teeth in a readily available storage medium within each family, more stem cells would be obtained. This research is about the effect of storage media and time on pulpal cell viability of exfoliated deciduous teeth. 330 exfoliated deciduous teeth were randomly divided into 11 groups; fresh group, dry group, groups stored in cell culture medium (2, 4, 7 days each), in milk (2, 4, 7 days each), and in saline (2, 4, 7 days each). Primary culture of pulpal cells was conducted in each group and the success rates were compared by calculating the number of teeth with viable cells. The result of primary culture shows that the success rate decreases as the time of storage gets longer. There was no statistical difference between groups stored in the cell culture medium, milk, and saline for 2 and 4 days. However, the groups stored in milk and saline for 7 days showed dramatic decrease in success rate compared to the group stored in the cell culture medium. In conclusion, exfoliated or extracted deciduous teeth can be used to culture pulpal cells when they are stored in milk and saline for a certain period of time; however obtaining viable pulpal cells becomes harder as the storage time gets longer.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.38 no.2
• /
• pp.146-154
• /
• 2011

An in vitro study on cariogenic potential of 8 over-the-counter syrups for children was performed. The experimental groups were 8 over-the-counter syrups. The positive control group was 10% sucrose solution, and the negative control group was artificial saliva. The pH of each group was determined. The buffering capacity was measured by the volume of 2 N NaOH adding to equalize the pH of 20 ml of experimental solution to pH 7. The consistency was measured by the time to pass Ostwald pipette for 2 ml of the experimental solution. The experimental solutions were inoculated with S. mutans and cultured in $37^{\circ}C$ anaerobic condition for 48 hours. To estimate acid production, pH of the experimental solutions were measured before and after the culture. The primary teeth specimens were soaked in the experimental solutions for 20 minutes three times a day. Except on those hours the specimens were stored in artificial saliva. After 5 days, the microhardness changes of the specimens were measured. These results show that most of syrup-form medicines for children tend to have cariogenic potential partially in endogenous pH, buffering capacity, consistency, acid production and erosive ability of enamel. For the oral health of children, the alternative sweeteners (ex. xylitol) may be substituted for the cariogenic sweeteners of syrups. Additionally, It may be helpful that the chewable tablet replace liquid or syrup in term of dose form.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.31 no.2
• /
• pp.144-152
• /
• 2004

The aim of this study was to evaluate the resistance to degradation of three commercial compomers in an alkaline solution. Dyract(Dentsply), Elan(Kerr) and F-2000(3M) polyacid modified resin composites(compomers) were used in this study. The resistance to degradation was evaluated on the basis of mass loss(%), degradation $depth({\mu}m)$ and Si, Al, Ba loss(ppm). The results were as follows : 1. The mass loss of each brand was $1.42%{\sim}2.14%$ and there was no statistically significant difference of mass loss among Dyract, F2000 and Elan. 2. The degradation layer depth of each brand was $182.92{\sim}227.7{\mu}m$ and there was no statistically significant difference of degradation layer depth among Dyract, F2000 and Elan. 3. There was statistically significant differences in Si-loss and Al-loss among three compomers (p<0.05). Si loss was the highest value in Dyract and Al loss was the highest value in F2000. 4. There was statistically significant correlation between mass loss and degradation layer depth (r=0.60, p<0.05). 5. In SEM finding, there was some destruction of compomer matrix-filler interface in post-exposure specimen to NaOH solution. As the matrix decreased, the filler particles distinguished and the periphery of the filler particles appeared whitish color due to degradation.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.32 no.4
• /
• pp.604-610
• /
• 2005

This study was to evaluate the effects of several light curing units on the microleakage of composite resin restorations in primary teeth. The types of curing units were traditional low intensity halogen light(Optilux 360), plasma arc light(Filpo) low heat plasma arc light(Aurys) and high intensity LED(Freelight 2). After preparing cavities on sound primary teeth, cavities were filled with composite resin(Z100) using the same resin bond agent(Scotchbond Multi-Purpose) and were cured with each curing light system. After storing each specimen in sterile water for 24 hours, thermal circulation was done 1,000 times followed by pigmentation using 2% methylene blue solution. Each specimen was sliced and the degree of pigmentation was graded. When microleakage is graded, the average of Aurys was 0.95 which was the lowest and Freelight 2(1.05), Filpo(1.25), Optilux 360(1.30) followed. But values were not shown statistically significant difference (P>0.05). The results suggest that the newly developed curing units which has advantage in children by decreasing discomfort and procedure time can increase the microleakage of the composite resin.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.32 no.3
• /
• pp.557-568
• /
• 2005

The aim of this study was to evaluate the resistance to degradation and to compare the wear resistance characteristics of four esthetic restorative materials in an alkaline solution(0.1N NaOH). The brands studied were MetafilCX(Sun medical, Japan) Solitaire 2(Heraeus Kulzer, USA), Composan LCM(Promedica, Germany), DenFil(Vericom, Korea). The results were as follows: 1. The mass loss of each brand was 0.74~7.94% and highest value in Metafil($7.94{\pm}0.39%$). 2. The sequence of the degree of degradation layer depth was in descending order by Metafil, Solitaire 2, DenFil, Composan LCM. There were significant differences between Metafil and the others(p<0.05). 3. The sequence of the Si loss was in descending order by Metafil, Solitaire 2, Composan LCM, DenFil. There were significant differences among the materials(p<0.05). 4. On SEM, destruction of bonding between matrix and filler and on CLSM, the depth of degradation layer of specimen surface was observed. 5. The sequence of maximum wear depth was in descending order by Metafil, Solitaire 2, Composan LCM and DenFil. There were significant differences among the materials(p<0.05). 6. The correlation coefficient between Si loss and degradation layer depth (r=0.491, p<0.05) and Vicker's hardness number and maximum wear depth (r=-0.942, p<0.05) were relatively high. These results indicate that hydrolytic degradation and wear may consider as a evaluation factors of composite resins.