In order to evaluate the pulp irritation by the restorative materials in detail, we developed a new testing method for examining the dentinogenesis ability of the pulp cells in the teeth filled with restorative materials. Actually, there exist apparent discrepancies between the results of cytotoxicity test and current pulp irritation test with some materials. It led us to develop the new method that enables to evaluate the irritation by restorative materials not by morphological changes but by functional changes of cells for dentinogenesis ability. The details of this test is as follows：after pulpotomy, the function of the pulp cell recovering from various irritations such as cavity preparation and filling is evaluated in terms of the amount of the formation and the degree of the maturation of dentin bridge formed under the surface of amputated pulp. Five restorative materials were examined with this method, and the results of the dentin bridge formation and maturation were different among the materials. It indicates that the irritation for the dentinogenesis ability of the pulp cells by the properties of each restorative material can be affected, and the response of pulp cells to the irritations can be quite different from the evaluation with the conventional pulp irritation test. The new pulp irritation test may explain such discrepancies of the result when compared with the cytotoxicity test. It was confirmed that the new testing method can be useful for pulp irritation test of restorative materials.

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Porcelain laminate veneer（PLV）restoration is generally accepted as one of aesthetic dental treatment to improve the discoloration of teeth. However, few long-term clinical studies have been reported. The present report shows a 25-year clinical follow-up case of PLV restorations that were carried out to improve severe discoloration of the maxillary anterior teeth（321 123）by tetracycline. Nine years after the first restorative treatment, partial fractures around cervical area of PLV on 23 were observed. These fractured PLV of 23 were removed, and re-restored by new PLVs. Twenty-five years after the first restoration, all PLVs were re-treatment because of the color change

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