Purification and characterization of bovine dental pulp collagenase inhibitor.

Root pulps from bovine unerupted wisdom teeth produce a potent collagenase inhibitor together with latent collagenase when cultured in Eagle's minimal essential medium (Biochem. Int. 5, 763, 1982). The inhibitor was purified more than 700-fold from the explant medium using Con A-Sepharose, Ultrogel AcA 44 and DE-52 cellulose columns. It showed a single band (MW = 36,000) on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, but showed multiple bands on basic (pH 8.3) polyacrylamide gel electrophoresis and electrofocusing. The inhibitor is a sialo-glycoprotein containing approx. 20% carbohydrate by weight and its composition suggests that it contains complex-type oligosaccharides. The electrophoretic heterogeneity of the inhibitor was proved to be due to the attachment of different numbers of sialic acid residues. All the SH groups were demonstrated to exist as six disulfide linkages which might be involved in the inhibitory activity. The bovine pulp inhibitor does not combine with collagen. The addition of the inhibitor to activated collagenase resulted in dose-dependent inhibition of the enzyme activity, but the interaction between the inhibitor and activated collagenase is not tight enough for the complex to remain intact during gel filtration column chromatography. A rabbit antiserum was prepared against the inhibitor, and immunoglobulin purified from the antiserum can completely abolish the inhibitory activity of the inhibitor.

In vivo and in vitro study of the effects of vitamin A deficiency on rat third molar development.

We have examined the effect of in vivo vitamin A status on subsequent rat third molar formation and mineralization in an in vitro organ culture system. Vitamin A deficiency imposed during an eight-day in vitro period caused effects very similar to those of vitamin A deficiency imposed on rats in vivo. Analysis of the data also demonstrates that retinoic acid is capable of reversing the interference in mineralization of third molars induced by vitamin A deficiency in the organ culture system.

The relative distribution of fluoride in erupted and unerupted enamel of human third molars from a low fluoride area.

Acid-etch biopsies were taken from the centre of the mesio-lingual, disto-lingual, disto-buccal and mesio-buccal cusps of non-carious erupted (n = 16, aged 18-28 years) and unerupted (n = 21, aged 18-28 years) teeth. The donor subjects had lived continuously in a low fluoride area (F water less than 0.1 parts/10(6] from birth, and had had no systemic fluoride supplementation. Tooth brushing, mouth rinsing and the application of sealers were the only fluoride-containing anti-caries programmes practised singly or in combination. Six successive acid-etchings were taken from each of the four cusps, and the fluoride levels in the etching solution were measured with an adapted, fluoride ion-selective electrode. Up to a depth of about 10 microns, unerupted enamel was etched significantly (p less than 0.05) more deeply than erupted enamel, which might be explained by changes in its composition. Up to a depth of approximately 10 microns, significantly more fluoride was found in erupted than in unerupted enamel. This difference may mainly be attributed to the effect of fluoride from the oral environment on erupted enamel. Fluoride concentrations, up to a depth of approximately 3 microns, were (p = 0.07) higher in the buccal cusps than in the lingual cusps of erupted molars, but not at the other etch depths. There were no significant differences (p greater than 0.10) between the buccal and lingual cusps of the unerupted molars at any depth. No significant correlations between enamel fluoride concentrations and age could be found either for erupted or unerupted third molars.

Methionine-enkephalin peptides in human teeth.

The presence of the free opioid pentapeptide methionine enkephalin (ME) and of ME-containing peptide(s) was established firmly in decalcified, depulped human teeth by using a combination of methods including RP-HPLC, radioimmunoassay, radioreceptorassay, trypsin, carboxypeptidase B, fast atom bombardment mass spectrometry, and MS/MS methodology. Positive structural identification of ME was made with mass spectrometry. Those data demonstrate the presence of the preproenkephalinergic A system in the human trigeminal sensory termini.

Fluoride distribution in the enamel of the mesio-lingual cusps of pairs of erupted and unerupted third molars of man with a low fluoride background.

The enamel fluoride concentrations at different depths were determined at 5 different sites on the mesio-lingual cusps of 16 pairs of erupted and unerupted third molars. Six successive acid etchings were done on each of the 5 sites. The 16 subjects (18 to 33 years) were living continuously since birth in a low fluoride area (F less than 0.10 ppm). They did not take any systemic fluoride since birth nor did they practise any other anti-caries fluoride program than brushing their teeth once or twice a day with fluoride-containing dentrifrices with about 1,000 ppm fluoride. The fluoride level in the etch solution was measured with the use of an adapted fluoride selective electrode. Statistically significant differences (p less than 0.05) were found in the mean etch depth between the erupted and unerupted molars, to a depth of approximately 5 micron. The mean enamel fluoride concentrations of the erupted and unerupted molars also differed significantly to a depth of approximately 5 micron. There was no influence of fluoride from the oral environment on enamel levels of approximately 10 micron and deeper. Over an exposure period of 1 to 16 years, sixty percent more enamel fluoride (at a depth of approximately 2 micron) was found in the erupted enamel relative to the unerupted enamel (with a low background fluoride) as a result of tooth brushing with fluoride-containing dentifrices. More enamel fluoride was found near the incisal edge than near the cervical margin of 14 of the 16 subjects independently of the age of the subjects.

[Structural, ultrastructural and microanalytical study of multiple enamel pearls]. / Etude structurale, ultrastructurale et microanalyse de perles d'émail multiples.

Numerous enamel drops and compound enamel pearls were found on the radicular proximal faces of maxillary molars and mandibular third molars of a young woman. Enamel and dentin of compound pearls as well as cementum next to drops and pearls presented the same structure and ultrastructure as enamel, dentin and cementum of the corresponding teeth. Microanalysis did not reveal differences between enamel of the mother tooth and enamel of drops and pearls. The enamel drops had no incremental growth lines. Cementum next to enamel drops and compound enamel pearls was acellular and covered occasionally with a thick layer of cellular cementum. Only enamel drops were partially covered by acellular cementum. Close to the enamel drops and at their surface, numerous fusing globular calcifications were observed. Formation of enamel drops and compound enamel pearls on dental root surfaces is rare. The simultaneous presence of numerous enamel drops and some compound enamel pearls on several roots of molars in the same denture seems to be an exceptional phenomenon. The involved factors inducing enamel formation remain still unknown. The multitude of both enamel drops and compound enamel pearl might be due to constitutional predisposition.