Intrinsic enzymatic crosslinking and maturation of the in situ pellicle.
OBJECTIVE
The acquired enamel pellicle is a proteinaceous layer formed on all solid substrata exposed to the oral cavity. It has been supposed that the pellicle undergoes maturation after protein adsorption. The aim of the present study was to investigate enzyme activities with an impact on intrinsic maturation processes in in situ formed pellicles.


METHODS
Bovine enamel specimens were exposed to the oral cavity in six subjects to allow in situ pellicle formation over 3, 30 and 120 min. The slabs were fixed on the buccal and palatal surfaces of individual splints fixed with silicone impression material. After rinsing with deionised water, the pellicle samples were tested fluorimetrically for transglutaminase, protease and elastase activity. Phosphatase activities were tested photometrically. Separate samples were used for each of the enzymes tested.


RESULTS
Transglutaminase was detected in in situ pellicle (16.7+/-21.2 mU/cm(2)) as was alkaline phosphatase activity (0.87+/-0.99 mU/cm(2)). For both enzymes, there was no correlation of enzyme activities with time or localisation of pellicle formation. Acidic phosphatase- and protease-activities were not detectable. Only traces of elastase activity were found in 57% of the samples.


CONCLUSIONS
Transglutaminase and phosphatase activity are detectable within in situ pellicle. Enzymatic crosslinking and dephosphorylation appear more important for intrinsic maturation of the acquired enamel pellicle than proteolysis.
Hannig
C
C
Department of Operative Dentistry and Periodontology, University of Freiburg, Hugstetter Street 55, D-79106 Freiburg, Germany. christian.hannig@uniklinik-freiburg.de
Spitzmüller
B
B
Miller
M
M
Hellwig
E
E
Hannig
M
M
D000327:Adsorption; D000328:Adult; D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D002417:Cattle; D003432:Cross-Linking Reagents / Q000378:metabolism; D044622:Dental Pellicle / Q000201:enzymology*; D005470:Fluorometry; D006801:Humans; D019272:Leukocyte Elastase / Q000378:metabolism*; D010447:Peptide Hydrolases / Q000378:metabolism*; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism*; D011503:Transglutaminases / Q000378:metabolism*
D003432:Cross-Linking Reagents; D011503:Transglutaminases; D000469:Alkaline Phosphatase; D010744:Phosphoric Monoester Hydrolases; D010447:Peptide Hydrolases; D019272:Leukocyte Elastase