Changes in Clinical Appearance and Hardness of Rat Incisors after Sodium Fluoride Administration

• Published in: JOURNAL OF DENTAL HEALTH Vol. 43; no. 5; pp. 651 - 658
• Main Authors: HIGUCHI, Hisahide, KONDO, Takeshi, NAKANE, Takashi, KASAHARA, Kaoru, KUROIWA, Shigeru
• Format: Journal Article
• Language: English
• Published: Japanese Society for Oral Health 1993
• Subjects: Attrition; Hardness of enamel; Pigmentation of enamel; Sodium fluoride
• ISSN: 0023-2831; 2189-7379
• DOI: 10.5834/jdh.43.651

One often sees cases of black and brown pigmentation on all enamel surfaces in schoolchildren with severe dental fluorosis. This pigmentation gradually disappears by attrition 4-5 years after eruption of the teeth. The reason seems to be decreasing hardness of the enamel. But this pigmentation is not seen all cases of fluorosis. Therefore, we tried to find the relationship between fluoride dose and incidence of pigmentation in the enamel of rats given 3.75-15.00mgF/kg/day in the form of NaF for 10 weeks. We obtained the following results: 1. Body weight and food intake decreased in group 3 given 15.00mgF/kg/day, but water intake in all experimental groups increased by dose. 2. There was no difference between control and experimental groups in number of erythrocytes, or in hemoglobin and hematocrit values, but leucocytes decreased in all experimental groups. 3. Activity of cholinesterase (Ch-E), creatin kinase (CPK) and triiodethyronine (T3) decreased by dose, but we could not find any reason for the decrease in activity of CPK and T3. 4. Whiteness was found in all incisors of the experimental groups and bands of black and brown pigmentation were especially found in the maxillary incisors of rats given 7.50-15.00mgF/kg/day. 5. Hardness of enamel and dentin of both jaw decreased by dose. The mandibular incisors were harder than the maxillary incisors. But attrition of the mandibular incisors was severer than that of rhe maxillary incisors irrespective of hardness.