Interindividual and longitudinal studies of amino acid composition of pellicle collected in vivo.

The formation of the acquired enamel pellicle is due to the adsorption of salivary proteins to the enamel surface. This adsorption is assumed to be specific and is dependent on the chemical characteristics of the surface. The aim of the present study was to investigate the consistency of the chemical composition of the acquired pellicle collected in vivo. Inter- and intraindividual differences in the chemical composition of pellicle material were examined during 2 yr in three different individuals. The amino acid profiles obtained from pellicle analyses were compared to hydrolyzed whole saliva collected at the same time as the pellicle material. The results showed that the amino acid composition of pellicle was consistent both between and within the individuals. The amino acid profiles obtained from the analyses of the saliva samples were different from the pellicle profiles, illustrating the selective nature of pellicle formation. This supports the contention that the adsorption of salivary proteins to dental enamel is a very specific process.

Morphologic and histochemical characteristics of the dental cuticle in teeth affected by prepubertal periodontitis.

A study was undertaken to determine the nature and composition of the cuticle found in teeth with generalized prepubertal periodontitis (PP). This was accomplished by using histological and histochemical methods on decalcified specimens. Forty-six permanent teeth which were extracted from three prepubertal periodontitis patients (siblings) were used. Nineteen of the 46 teeth were obtained with the facial or interdental gingiva. As a control, 20 healthy teeth extracted from 10 children for orthodontics reasons, and 22 teeth affected by terminal adult periodontitis (AP), were used. All the teeth with PP showed a thick coat covering the root surface from the cemento-enamel junction to the junctional epithelium. In some teeth the cuticle extended a few microns coronally to the cemento-enamel junction. The cuticle had a thickness which varied between 10 to 80 microns. It usually presented a very regular surface in the coronal portion of the root, and showed laminations suggesting appositional growth. In the middle and apical portions of the root exposed to the pocket, the cuticle was lobular with a very irregular surface and was covered with a thick microbial plaque. The staining reactions indicated that the cuticle was made of proteins probably derived from the inflammatory exudate. None of the healthy teeth examined nor those affected by AP showed a cuticle similar to those with PP. The cuticle formed on the teeth with PP appears to be an abnormal structure of proteinaceous nature, characteristic of these teeth, and may possibly play a role in the pathogenesis of the disease.

[Zinc and caries]. / Tsink i karies.

Zinc levels in dentin, enamel, tooth deposit, and mixed saliva in caries were under study. The enamel and dentin Zn levels were measured by means of neutron activation analysis in 244 permanent intact teeth and in 92 permanent carious teeth from subjects died after acute injury. Tooth deposit and mixed saliva Zn levels were measured by the atomic absorption technique in 10 patients with caries and in 10 normal subjects; the groups were matched for dietary habits. The menu of these subjects over a month was examined and the content of daily dietary zinc was determined, and the level of salivary Zn excretion as against Zn content in the food was calculated. The dentin and enamel Zn levels were found increased in caries. A tendency to an increase of Zn level in the saliva was detected; a large proportion of this dietary element was excreted with the saliva in caries patients. The authors suggest that remineralization effect can be achieved in the initial stages of caries by oral and local application of Zn preparations.

Protein adsorption to hydroxyapatite and to calcium fluoride in vitro and amino acid analyses of pellicle formed on normal enamel and on calcium-fluoride-covered enamel in vivo.

Fluoride treatment of enamel has been reported to result in the formation of a layer of a CaF2-like material on the enamel surface. Protein adsorption to enamel is a specific process dependent on the nature of the surface, and little is known about protein adsorption to CaF2. Albumin and lysozyme were adsorbed to hydroxyapatite (HA) and CaF2 powder in vitro, and protein adsorption patterns constructed. In vivo pellicle was collected from three volunteers from fluoride-treated enamel and from normal enamel, and the amino acid compositions analyzed separately. The results showed that CaF2 took up small amounts of proteins as compared with HA. When the CaF2 was pretreated with a phosphate buffer, pH 6.8, the protein adsorption increased markedly. The amino acid analyses showed no major differences in the amino acid compositions between pellicle collected from CaF2-covered enamel and pellicle collected from normal enamel. This lack of difference is presumably due to the adsorption of phosphate ions to the CaF2 crystals and hence changed surface properties.

Characterization of in vivo salivary-derived enamel pellicle.

Salivary proteins and glycoproteins that participate in the formation of 2-h in vivo enamel pellicle were determined utilizing polyacrylamide gel electrophoresis [sodium dodecyl sulphate (SDS)-PAGE and anionic PAGE]/Western transfer analyses, and specific radiolabelling/SDS-PAGE fluorography. The sensitivity of these methods permitted the identification of individual members of different salivary protein families. The major components of this pellicle were salivary alpha-amylase, cysteine-containing phosphoprotein (CCP or cystatins), salivary mucin and sIgA. Glycosylated amylase was present in larger quantity than the non-glycosylated species. Only CCP1 (cystatin SA-I) of the cysteine-containing phosphoprotein family was identified. The higher molecular-weight salivary mucin (MG1), but not the lower molecular-weight species (MG2), was detected. These results extend earlier observations regarding the selective nature of salivary protein adsorption to enamel surface by demonstrating that only specific members of salivary protein families are involved in 2-h in vivo enamel pellicle formation. The findings also suggest that individual family members may have different functions in the mouth.

Lipopolysaccharide (endotoxin) from individual periodontally involved teeth.

The amount of lipopolysaccharide (LPS) in the root surface-associated material from individual periodontally-involved teeth has been determined. LPS was found in the surface material from all of the teeth and the amount present ranged from 19-394 ng/tooth. No significant correlation was found between the amount of LPS extracted from a particular tooth and the mean pocket depth associated with the tooth. However, a weak correlation (rs = +0.461, 0.05 greater than p greater than 0.01) was found between the amount of LPS and the % loss of attachment.

External radiolabelling of components of pellicle on human enamel and cementum.

Enamel and cementum pellicles form by different adsorption of salivary and serum components to the tooth surface. The authors compared the constituents of surface pellicle formed on human enamel and cementum under three conditions: (1) natural pellicle, present on extracted teeth, which was formed by prolonged exposure to human salivary and serum components in vivo; (2) short-term in-vivo pellicle, formed by exposing enamel and cementum slabs to the oral environment for 0-60 min; (3) in-vivo pellicle, formed by incubating enamel and cementum slabs in a 1:1 mixture of parotid and submandibular/sublingual saliva for 0-60 min. Pellicle composition was characterized by external radiolabelling techniques specific for exposed carbohydrate (sialic acid and galactose) and amino-acid (tyrosine) residues. There were differences between cementum and enamel in the electrophoretic profiles of natural-pellicle components; notably, a major 180 kda 3H-labelled sialoglycoprotein, unique to the cementum pellicle, had the same electrophoretic mobility as the low-molecular-weight mucin from human submandibular/sublingual saliva. After alkaline-borohydride treatment, 3H-labelled natural-pellicle oligosaccharides chromatographed in the di- to tetrasaccharide region of a Bio-Gel P-2 column. The most prominently labelled components of short-term enamel and cementum pellicles in vivo and in vitro had the same electrophoretic mobility as the low-molecular-weight salivary mucin. The pellicle components formed in vitro, unlike those formed for the same period of time in vivo, were rapidly desorbed from the cementum, but not from the enamel surface. We conclude that: (1) external labelling techniques are useful for obtaining a profile of pellicle components; (2) submandibular/salivary mucins are major constituents of salivary pellicles on tooth surfaces; (3) glycoproteins that carry low-molecular-weight, sialic-acid-containing saccharides are important determinants of pellicle surface properties [corrected].

Studies on the organic polyanionic constituents of human acquired dental pellicle.

Extracts of acquired dental pellicle were obtained by a two-step procedure. Pellicle formed on cleaned teeth was first extracted using 2 M CaCl2, and the remainder then removed by scraping followed by solubilization in 5 per cent (w/v) EDTA. The 2 M CaCl2 extract contained high-molecular-weight glycoprotein which was present in only trace amounts in the EDTA extract. Cellulose-acetate electrophoresis of both extracts revealed low-molecular weight protein which contained phosphate. This protein tentatively identified as a phosphoprotein, disappeared as the pellicle matured. The findings have implications in relation to early bacterial colonization of the tooth surface.

Tooth surface-pellicle lipids and their role in the protection of dental enamel against lactic-acid diffusion in man.

The lipid content and composition of the enamel pellicle from caries-resistant (CR) and caries-susceptible (CS) subjects and their effect on its ability to retard the diffusion of lactic acid were investigated. Lipids accounted for 22.2 per cent of the dry weight of CR pellicle and 23.7 per cent of CS pellicle. The content of glycolipids in both groups was similar but CR pellicle contained 42 per cent less neutral lipids and 31 per cent less phospholipids. CR lipids had a higher content of cholesterol, cholesterol esters and sphingomyelin, whereas CS pellicle was richer in free fatty acids and phosphatidylethanolamine. Retardation of lactic-acid diffusion by CR pellicle was 45 per cent higher than by CS. Removal of lipids caused 50 per cent reduction in retardation by CR pellicle and 35 per cent by CS pellicle.

Characterization of saliva proteins from 'stainers' and 'non-stainers' adsorbed to hydroxyapatite.

Stainers and non-stainers were selected on the basis of their individual tendency to develop extrinsic tooth discolorations from a chlorhexidine mouth rinse. Saliva proteins adsorbed to hydroxyapatite in vitro and in vivo pellicle from the participants were analyzed by gel filtration and ion-exchange chromatography. Two distinct anionic components were isolated. The elution patterns from stainers and non-stainers were identical. Amino acid analyses of the main peaks demonstrated a prevalence of serine, glycine, and glutamic acid.

Auger electron spectroscopy of iron in dental pellicle from stainers and non-stainers.

Stainers and non-stainers were selected on the basis of their individual tendency to develop extrinsic tooth discolorations from a chlorhexidine mouth rinse. Pellicle was allowed to form in vivo on dental enamel slabs in both stainers and non-stainers. The slabs were then exposed to chlorhexidine 0.2% and a neutral iron salt solution extraorally either once or until a brownish discoloration appeared from the stainers. The pellicle was examined for its content and distribution of iron by Auger electron spectroscopy (AES). Pellicle from stainers showed higher concentrations of iron than pellicle from non-stainers.

Further studies on the composition of the acquired enamel pellicle.

In the present study pellicle material was collected from human teeth 2, 4 and 6 hr after cleaning. The material obtained was examined by gel filtration, ion exchange chromatography on CM-Sephadex and DEAE-Sephadex with subsequent amino acid analyses of the major anionic component. No major changes were observed to occur either in the overall composition or in the main anionic component of the pellicle during the first 6 hr.

Identification of IgA, IgG, lysozyme, albumin, alpha-amylase and glucosyltransferase in the protein layer adsorbed to hydroxyapatite from whole saliva.

IgA, IgG, albumin, lysozyme, alpha-amylase and glucosyltransferase were identified in the saliva coat which forms on hydroxyapatite exposed to whole saliva. It is suggested that these proteins may be involved in binding microorganisms to saliva coated hydroxyapatite in model studies.

Gel filtration, ion exchange chromatography and chemical analysis of macromolecules present in acquired enamel pellicle (2-hour-pellicle).

Proteins obtained from the surface of human teeth in vivo were solubilized in EDTA and subjected to gel permeation, ionic exchange chromatography and amino acid analysis. It was found that the main component was anionic and was eluted between albumin and lysozyme on Sepharose. It contained abundant amounts of serine, glycine and glutamic acid. A salivary phosphoprotein of similar amino acid composition has previously been purified.

Iron staining of the acquired enamel pellicle after exposure to tannic acid or chlorhexidine: preliminary report.

Extrinsic discoloration of teeth following a large consumption of tannin-containing beverages or a prolonged use of chlorhexidine mouthrinses is a well known observation. Tannins as well as chlorhexidine are denaturing agents. Based on preliminary studies revealing the presence of iron in chlorhexidine discolored pellicle material, the ability of iron to stain the integument after pretreatment with the two denaturants was studied in a human model. The denaturing effect of an acidic environment was also included. Enamel slabs fixed to acrylic appliances were carried in the oral cavity and alternately exposed to the test solutions in different sequences in vitro. Pretreatment with chlorhexidine or tannic acid led to marked discoloration upon iron application during 5-d tests, whereas the compounds individually had no such effect. A large content of the metal was found in the stained material. Stannous fluoride appeared to reduce the formation of the pigments, and strong oxidation completely bleached the established color. Possible mechanisms underlying the phenomena observed are discussed.