• Restorative Dentistry and Endodontics
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• v.31 no.6
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• pp.470-476
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• 2006

The objective of this in situ study was to evaluate the effects of whitening strip (Claren, LG Household & Health Care Ltd, 2.6% hydrogen peroxide) and gel (Opalescence, Ultradent, 10% carbamide peroxide) on microhardness of enamel in comparison with untreated control. Extracted twenty human upper incisors were disinfected, cleaned, and labial side of each incisor sectioned into 3 fragments by 2 ${\times}$ 2 mm size. After sectioning, labial sides of fragments were flattened and fixed to orthodontic bracket using flowable composite resin. Specimens prepared from each tooth were attached to the labial side of upper incisors of twenty volunteers one by one and treated by three different methods: (1) untreated control (2) treated with whitening strip for 14 days (3) treated with whitening gel for 14 days. Microhardness (Microhardness tester, Zwick) of each specimen was measured at the baseline of pre-treatment, immediate after bleaching treatment, 14 days after bleaching treatment and Knoop Hardness Number was determined. Microhardness changes of experimental groups were compared. The results show that tooth whitening strip and gel used in this study does not effect the microhardness of enamel during bleaching procedure.

• Restorative Dentistry and Endodontics
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• v.29 no.3
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• pp.219-225
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• 2004

This study evaluated the microshear bond strength of composte resin to teeth bleached with commercial whitening strips and compared with those bleached with home bleaching gel. Twelve extracted human central incisors were cut into pieces and central four segments were chosen from each tooth and embedded in acrylic resin. Four blocks with 12 tooth segments embedded in acrylic resin were acquired and numbered from group one to group four. Group 1 was bleached with Crest Whitestrips, group 2 with Claren, group 3 with Opalescence tooth whitening gel (10％ carbamide peroxide). Group 4 was used as control. The bleaching procedure was conducted for 14 days according to the manufacturer's instructions ; the bleaching strips twice a day for 30 min and the bleaching gel once a day for 2hr. After bleaching, composite resin (Filtek Supreme) was bonded to the enamel surfaces with a self-etching adhesive (Adper Prompt L-Pop) using Tygon tube. Microshear bond strength was tested with a universal testing machine (EZ-test). The data were statistically analysed by one-way ANOVA. The study resulted in no statistical differences in microshear bond strength between the tooth segments bleached with 2 different whitening strips and bleaching gel. It can be concluded that the effect of bleaching with either commercial whitening strips or bleaching gel on enamel is minimal in bonding with self-etching adhesive to composite resin.

• Proceedings of the KACD Conference
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• 2003.11a
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• pp.573-573
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• 2003

I. Objective This study evaluated the microshear bond strength of teeth bleached with commercial whitening strips and compared with those bleached with home bleaching gel. II. Materials and Methods Twelve exrtacted central incisors were cut into pieces and central four segments were chosen from each tooth and embedded in acrylic resin. Four blocks with 12 tooth segments embedded in acrylic resin were acquired and numbered from one to four. Block 1 was bleached with Crest Whitestrips, block 2 with Claren, block 3 with Opalescence tooth whitening gel(10% carbamide peroxide).(omitted)

• Hwankyungkyoyuk
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• v.15 no.1
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• pp.51-67
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• 2002

There are some critiques of Hungerford's "responsible environmental behavior" for misinterpreting or misunderstanding the term of "behavior". Most critics such as Wals and van der Leij, Jae-Young Lee misunderstood that Hungeford and his colleagues' approach to environmental education is a sort of behaviorism which is not correct. The writer corrected them by showing the successful story of the IEEIA program from the teachers, the children, and the community members digging by the foot. The IEEIA program represents his philosophy of education which can be characterized a non-behaviorist by Wals and van der Leij, if we attempt to classify all educators as behaviorist and non-behaviorist. And the writer also criticized the critiques with the well known "professional environmental educators" in the North America who have known Hungerford's ideas in environmental education well such as Roth, McClaren, Ramsey and Hungeford himself. Ramsey and Hungeford himself.