HISTOLOGICAL AND BIOCHEMICAL STUDY ON THE MECHANISM OF DEVELOPMENTAL DEFECT OF DENTAL HARD TISSUES
Grant-in-Aid for Scientific Research (C)
|Allocation Type||Single-year Grants|
|Research Institution||TSURUMI UNIVERSITY|
OHNO Kohachiro TSURUMI UNIV., SCHOOL OF DENTAL MEDICINE,DEPARTMENT OF PEDIATRIC DENTISTRY ASSOCIATE PROFESSOR, 歯学部, 助教授 (70014206)
|Project Period (FY)
1994 – 1996
Completed(Fiscal Year 1996)
|Budget Amount *help
¥2,000,000 (Direct Cost : ¥2,000,000)
Fiscal Year 1996 : ¥700,000 (Direct Cost : ¥700,000)
Fiscal Year 1995 : ¥400,000 (Direct Cost : ¥400,000)
Fiscal Year 1994 : ¥900,000 (Direct Cost : ¥900,000)
|Keywords||Developmental tooth defect / Mechanism / Histological feature / Electron microscopic observation / Biochemical analysis / Spectrophotometry|
The aim of this study was to investigate histologically and biochemically the mechanism of developmental defect of dental hard tissues. This study consisted of following three sections.
I) Exchange anomalies of the dentitions
II) Adsorption mode of tetracycline in dental hard tissue
III) Dens evaginatus in the permanent dentition
The first section materials were the extracted teeth obtained from a case of exchange anomalies of the dentitions. The second materials were tetracycline solution with various concentrations of calcium ion. The third subjects were 3.003 patients who had dens evaginatus in the permanent dentition.
The specimens prepared from the extracted teeth were observed optically as well as electron microscopically, and then tooth substances were analyzed chemically by using the enamel biopsy technique. Spectrophotometry was employed for the optical density of tetracycline in calcium ion solutions. The incidence of dens evaginatus of permanent teeth was retrospectively surveyed
by using the X-ray films and oral examination records.
The results obtained were as follows :
I) Calcitonin level in serum (287pg/ml) was specifically high in the case of disorder of endocrine glands. The histological observation was characteritic that any odontoclasts were not seen in the root resorption sites. These data suggested that the primary cause of exchange anomalies of the dentitions was hypersecretion of calcitonin.
II) In spectrophotometry, the absorbance value increased in acordance with in creases in the ratio off calcium ions against tetacycline. In the adsorption experiment, clear fluorescence bands were recognized in the enamel protein bands corresponding to molecular weights, enamel proteins of 32kDa, 13kDa and smaller molecules.
III) Seven patients (0.23%) showed incisive tubercles. Eighty-eight patients (2.93%) showed central cusps. One patient showed both kinds of dens evaginatus. The numbers of cnetral cusps observed among the premolars were respectively 96 lower second premolars (41%), 71 lower first premolars (30%), 37 upper second premolars (16%) and 30 upper first premolars (13%). Less
Research Products (9results)