• Journal of Korean society of Dental Hygiene
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• v.12 no.1
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• pp.81-91
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• 2012

Objectives : By investigating antimicrobial activity of natural extracts, identifying its usefulness as antibiotic material to oral bacteria. Methods : Antimicrobial activity tests of 25 natural extracts were implemented on 6 type strains alleged to cause dental caries and 10 clinical strains isolated and identified from dental caries. Results : Among medicinal plants, Coptis japonica, Scutellaria baicalensis, Dictamnus dasycarpus showed antimicrobial activity. Among lichens, 3 methanol extracts and 6 acetone extracts showed antimicrobial activity. Minimum Inhibitory Concentration(MIC) test of Usnea aurantiacoatra KoLRI 004184, an acetone extract of lichen with the highest antimicrobial activity, on 6 type strains involved in dental caries and 10 strains isolated from dental caries resulted as follows; Actinomyces oris 1041 $12{\mu}g/ml$, for Corynebacterium durum 3151 $13{\mu}g/ml$, for Rothia dentocariosa KCTC $3204^T$ $14{\mu}g/ml$, for R. dentocariosa 911 $15{\mu}g/ml$, for R. dentocariosa 1822 $12{\mu}g/ml$, for Lacto-bacillus casei KACC $12413^T$ $12{\mu}g/ml$, for L. acidophilus KACC $12419^T$ $16{\mu}g/ml$, for L. rhamnosus 2421 $15{\mu}g/ml$, for Streptococcus mutans KCTC $3065^T$ $15{\mu}g/ml$, for S. mutans 121 $13{\mu}g/ml$, for Streptococcus oralis 2221 $18{\mu}g/ml$, for S. salivarius KCTC 5512 $14{\mu}g/ml$, for S. salivarius 122 $12{\mu}g/ml$, for S. sanguinis KCTC $3284^T$ $14{\mu}g/ml$, for S. sanguinis 912 $14{\mu}g/ml$, for Neisseria sp. KEM232 $12{\mu}g/ml$. Conclusions : Even a small amount of extract from lichen Usnea aurantiacoatra KoLRI 004184 showed very high level of antimicrobial activation against all 16 bacterial strains involved in dental caries.

• Journal of Korean society of Dental Hygiene
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• v.12 no.1
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• pp.93-101
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• 2012

Objectives : The purpose of this study was to examine the educational effect of cooperative learning, which enables learners to make portfolio by taking advantage of their knowledge and skills acquired through practice, on an oral prophylaxis practice course in an attempt to stir up the spontaneous learning of learners, their learning interest and problem-solving skills. Methods : The selected dental hygiene students engaged in cooperative learning in oral prophylaxis practice III class in the second semester of their sophomore year by utilizing portfolio that was prepared by altering an inclusive dental hygiene practice model. They completed all the 15-week practice course, and then their portfolio was evaluated. They were divided into eight nonequivalent groups whose members were all different in academic standing, and their learning strategies and academic self-efficacy were checked before and after the instruction was provided. And their satisfaction with the class was investigated after the instruction was provided. Results : 1. There were significant gaps to $0.36{\pm}0.07$ in the charge of learning strategies after they engaged in cooperative learning(p<0.01). There were the broadest differences in cognitive strategies to 3.61, followed by metacognitive strategies to 3.19, and significant differences were found in all the subfactors(p<0.01). 2. There were significant gaps in the charge of self-efficancy to $0.13{\pm}0.06$ after they engaged in cooperative learning(p<0.01). There were the widest differences in self-regulating efficancy to 3.49, followed by confidence to 3.03 and task difficulty preference to 2.97, and significant differences were found in all the subfactors(p<0.01). 3. When their satisfaction level was analyzed after engaging in cooperative learning, there were significant gaps to 3.94 in the satisfaction level with all of the lectures(p<0.01). There were significant gaps in the satisfaction level with lecture to 4.20, with ensuring academic achievement to 4.13 and with cooperative learning to 3.48 (p<0.01). Conclusions : The above-mentioned findings indicated that cooperative learning had a positive impact on the learning strategies, academic self-efficacy and class satisfaction of the learners, and this study is expected to lay the foundation for the development of new teaching methods for dental hygiene.