• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.2
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• pp.318-332
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• 2000

The purpose of this study was to investigate the effects of demineralized freeze-dried bone (DFDB) on mechanically exposed pulp of dog by evaluating the pulpal inflammation and healing process, formation of dental hard tissue, and structural changes of fibroblasts of the remaining pulp tissue. Teeth of 4 dogs, weighing 10kg, were used in this study. Class V cavities were prepared followed by exposed the pulp tissue mechanically by sterilized round bur. In control group, exposed pulps were capped with calcium hydroxide paste followed by sealed with IRM. In experimental groups, the exposed pulps of one group were capped with the collagen and those of the other group were capped with DFDB. All cavities were sealed with same manor as control group. The animals were sacrificed at the intervals of 3, 7, 14, and 28 days for histopathlogic evaluation. The specimens were observed by the light microscope and trans-electron microscope. The results were as follows: 1. Pulp necrosis was not observed in all groups. Inflammatory response was disappeared from 1 week in control group and group 2. But it was not disappeared until 2 weeks and also irregular arrangement of odontoblasts was showed at the lateral walls of root canal just beneath the amputated site of the pulp in group 1. 2. Dentinal bridge was formed incompletely at 2 weeks but it was formed completely at 4 weeks in control group. Odontoid tissue was also found in control group at 4 weeks from treatment. Amputated site of pulp was encapsulated with fibrous tissue and odontoblast and dentinal bridge was not found in group 1. Preodontoid tissue and reparative dentin which were formed by odontoblast differentiated around DFDB were found, but dentinal bridge was not found in group 2. 3. Cell with large basophillic-stained nuclei infiltrated to amputated site and DFDB at 1 week from treatment in control group and group 2. They were found more in group 2 than in control group. Odontoblasts arranged more regularly and reparative dentin was found more as time elapsed. 4. Dentin-formative odontoblasts which showed ultramicrostructure of cytoplasm with polarized nucleus, rEM, Golgi complex, secretory granules, secretion of organic matrix in control of group and group 2. In regards to above results, the demineralized freeze-dried bone(DFDB) induce odontoblastic differentiation and further come up to the dentin formation in amputated pulp.

• Restorative Dentistry and Endodontics
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• v.30 no.3
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• pp.158-169
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• 2005

This study was done to evaluate the shear bond strength between light-cured glass ionomer cement (GIC) base and resin cement for luting indirect resin inlay and to observe bonding aspects which is produced at the interface between them by SEM. Two types of light cured GIC (Fuji II LC Improved, GC Co. Tokyo, Japan and Vitrebond$^{TM}$, 3M, Paul Minnesota U.S.A) were used in this study. For shear bond test, GIC specimens were made and immersed in 37$^{\circ}C$ distilled water for 1 hour, 24 hours, 1 week and 2 weeks. Eighty resin inlays were prepared with Artglass$^{(R)}$ (Heraeus Kultzer Germany) and luted with Variolink$^{(R)}$ II (Ivoclar Vivadent, Liechtenstein). Shear bond strength of each specimen was measured and fractured surface were examined. Statistical analysis was done with one-way ANOVA. Twenty four extracted human third molars were selected and Class II cavities were prepared and GIC based at axiopulpal lineangle. The specimens were immersed in 37$^{\circ}C$ distilled water for 1 hour, 24 hours, 1 week and 2 weeks. And then the resin inlays were luted to prepared teeth. The specimens were sectioned vertically with low speed saw. The bonding aspect of the specimens were observed by SEM (JSM-5400$^{(R)}$, Jeol, Tokyo, Japan) .There was no significant difference between the shear bond strength according to storage periods of light cured GIC base. And cohesive failure was mostly appeared in GIC On scanning electron micrograph, about 30 - 120 $\mu$m of the gaps were observed on the interface between GIC base and dentin. No gaps were observed on the interface between GTC and resin inlay.