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Many studies have been made of pulpal reactions to pulp protection (lining) materials have always employed a smear layer between the dentin wall and the lining materials. In this study, the author has attempted to evaluate pulpal response without a smear layer and compared effects of pulp protection (lining) with and without smear layers. Materials and methods. The experiment employed 84 vital human teeth ranging in age from 14 to 54 years. The experimental teeth were divided into 4 groups for the purposes of histopathological studies and scanning electron microscope (SEM) observation. Group C: No EDTA-treatment and lining with gutta-percha temporary material, 10 cases for histopathological study and 4 cases for SEM observation. Group TC: EDTA-treatment and lining with gutta-percha temporary material, 10 cases for histopathological study and 4 cases for SEM observation. Group P: No EDTA-treatment and lining with Protect Cement. 20 cases for histopathological study and 8 cases for SEM observation. Group TP: EDTA-treatment and lining with Protect Cement. 20 cases for histopathological study and 8 cases for SEM observation. After local anesthesia, Black's simple class I cavities were made in the experimental teeth with a diamond instrument mounted on a high-speed air turbine at room temperature with a water spray coolant. In Groups TC and TP only, an aqueous solution of 0.5% EDTA (pH 7.4) 10 ml was applied from cavity floor to dentin for 60 seconds. All cavities were then washed with distilled water, and the dentin was dried with an air stream. The floor of cavities were lined with thin layers of the following materials: Group C and TC, gutta-percha temporary material (G-C Dental Industrial Co., Tokyo, Japan). Group P and TP lining of Protect Cement which is a zinc phosphate cement containing 0.5% paraformaldehyde (Neo Dental Chemical Products, Tokyo, Japan). The restoration of each cavity was then filled with silver amalgam. Experimental teeth were clinically observed for 2 periods: short (about 14 days) and long (about 60 days) after treatment. They were then extracted under local anesthesia and prepared for histopathological study and SEM observation. Results 1. Clinical observations. During the observation period, symptoms occurred as indicated below. Group C: 2 (20%) out of 10 cases Group TC: 3 (30%) out of 10 cases Group P: None out of 20 cases Group TP: 3 (15%) out of 20 cases The only kind of clinical discomfort observed hypersensitivity to cold water. 2. Clinical evaluations Group C: 10 cases (100%) were good.(ABSTRACT TRUNCATED AT 400 WORDS)

The author biochemically evaluated the possible application of 4 types of alpha-cyanoacrylate adhesive agents (methyl, ethyl, isopropyl and isobutyl) in dentistry. A semiconductor temperature sensor was used to measure alpha-cyanoacrylate polymerization-temperature maximum heat, and an oscilloscope was employed to measure heat value. Amounts of formaldehyde eluted from the soluble component of alpha-cyanoacrylate was measured colorimetrically. In addition, to evaluate the effects of alpha-cyanoacrylate on pulp tissue, the soluble component of alpha-cyanoacrylate polymer was added to mouse macrophages. Changes in the numbers and morphology of macrophages and their glucose consumption in the supernatant medium were studied and compared with corresponding data obtained when formaldehyde alone was used. (1) During the polymerization of alpha-cyanoacrylate, when a glass fiber disc filter was used, the temperature increased by 19.1 degrees C in 1 microliter with methyl and by 8.6 degrees C with isobutyl. Even with the same alkyl, however, polymerization heat differed depending on the structure and constitution of the adhesive material and varied widely according to experimental conditions. (2) A mean maximum temperature of 1.7 degrees C in the dentin floor during polymerization of 10 microliters of alpha-cyanoacrylate monomer with methyl suggests no thermal injury to the pulp. (3) Formaldehyde was detected in all 4 adhesives when alpha-cyanoacrylate was dropped into distilled water for polymerization. Since, with each alkyl, the amount of eluted formaldehyde reached a maximum after 1 day of immersion, continuous elution of formaldehyde by hydrolysis was negligible. (4) A greater amount of formaldehyde was eluted from the polymer with methyl and ethyl, which have less Cs, than from the polymer with isopropyl and isobutyl, which have more Cs. These findings suggest that alkyl type affects the amount of eluted formaldehyde. (5) The soluble component of the alpha-cyanoacrylate polymer, either methyl or ethyl, had no effect on the number or morphology of mouse macrophages, as compared with corresponding data obtained when sterilized distilled water was used as a control. Isopropyl and isobutyl, however, decreased cell count and inhibited the extension of the sell soma. (6) The effects of isopropyl and isobutyl on the numbers and morphology of macrophages were similar to those of formaldehyde used alone at a concentration of 8 ppm or more. These findings suggest that, under the present experimental conditions, the above-mentioned changes in macrophages are the effects of about 8 ppm of formaldehyde. (7) The rate of glucose consumption by macrophages with methyl or ethyl was as high as that with the control.(ABSTRACT TRUNCATED AT 400 WORDS)

The present paper reports results of a study to evaluate clinico-pathologically the effects of calcium hydroxide eugenol preparations on exposed pulp tissues in permanent human teeth. The experiments were performed on 80 vital human teeth from patients ranging in age from 12 to 54 years. The experimental teeth were arbitrarily divided into the following 4 groups. Group CRCS: 20 cases treated with CRCS (Hygienic, Akron, Ohio, USA). Group KEZ: 20 cases treated with Dentalis KEZ (Neo Dental Chemical Products, Tokyo, Japan). Group CE: 20 cases treated with calcium hydroxide eugenol (positive control) Group E: 20 cases treated with pure eugenol (negative control). After local anesthesia, the experimental teeth were isolated with rubber dums or cotton rolls. Following preparation of Black's simple class 1 cavities with a diamond instrument mounted high-speed air turbine, the pulp was intentionally exposed by means of a steel bur mounted electric engine. The cavity and exposed pulp surface were cleaned with saline and dried on absorbent material. Then the experimental materials (agents) were applied to exposed pulp surface. The cavity was lined with gutta-percha temporally stopping, and the remainder was filled with silver amalgam. The teeth were clinically observed at various intervals from immediately to 530 days after treatment and then extracted under local anesthesia and prepared for histopathological study. Decalcified sections were stained with hematoxylin and eosin. 1) CLINICAL OBSERVATIONS: During the observation period, symptoms occurred in the following: Group CRCS: 4 (20%) out of 20 cases. Group KEZ: 4 (20%) out of 20 cases. Group CE: 6 (30%) out of 20 cases. Group E: None of 20 cases No spontaneous pain was observed in these groups. 2) Clinical evaluations Group: CRCS: 16 cases (80%) were good, 3 cases (15%) were satisfactory, and 1 cases (5%) were failure. Group KEZ: 16 cases (80%) were good, 1 cases (5%) were satisfactory, and 3 cases (15%) were failure. Group CE: 14 cases (70%) were good, 4 cases (20%) were satisfactory, and 2 cases (10%) were failure. Group E: 20 cases (100%) were good. 3) Histopathological observations. Various kinds and degree of pulp changes were occurred in each group. Hyperemia and round-cell infiltration resulting from damage caused by treatment and medicaments were frequent in each group. No suppurative inflammation occurred in group CE. Pulp cicatrization and apposition of dentin on pulp chamber walls were observed frequently in each groups. Hard tissue formation was observed in numerous cases of group CE and in some cases in group CRCS and KEZ.(ABSTRACT TRUNCATED AT 400 WORDS)