| Budget Amount *help |
¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 2003: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 2002: ¥1,100,000 (Direct Cost: ¥1,100,000)
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| Research Abstract |
Endodontically treated teeth due to dental caries and trauma are generally restored with post and cores and then crowned resulting in recovery of their function and esthetics.
We examined proportional limit and bending elastic modulus of several kinds of fiber posts in 2002 and obtained the following findings that those posts have almost the same strength as the prefabricated metal post with high elasticity and flexibility.
In 2003 we did an additional experiment from the clinical view point. Eighty bovine teeth simulating the human upper central incisors fabricated by Celay system (Mikrona, Switzerland) were prepared and divided into 4 groups by core-buildup method ; composite resin post and core (R), composite resin core with prefabricated metal post (MR), composite resin core with fiber post (FR) and conventional cast post and core (M). After building up cores, metal crowns were fabricated and cemented. Then fracture strength was measured before and after cyclic loading that loaded with 250N at every second until 300,000 times and also their fracture modes were observed and recorded.
As a result, FR showed the highest fracture strength in all core buildup methods before cyclic loading and better fracture mode with no root fracture, while MR and M using metal posts indicated root fracture. After cyclic loading, fracture strength of FR decreased but statistically with no difference.
In conclusion, composite resin core with fiber post can be higly resistant to root fracture and even if root fracture occurs, the root can be saved and restored in high possibility.
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