Lack of association between lactotransferrin polymorphism and dental caries.

OBJECTIVE: Dental caries is a complex, multifactorial disease and one of the most common illnesses worldwide. Its etiology is related to microbial, dietary and host factors. Recent evidence suggests a role of lactotransferrin (LTF) in caries. The purpose of this study was to determine the association between LTF gene polymorphism and dental caries. METHODS: In this case-control study, 637 unrelated children, aged 11-13 years, were enrolled. The subjects were divided into two groups, i.e. caries-free (decayed/missing/filled teeth = 0) and caries-affected children (decayed/missing/filled teeth ≥ 1). The LTF rs1126478 (140A/G in exon 2, Lys/Arg) genotypes were determined by PCR with restriction analysis using the EarI enzyme. RESULTS: Of 637 children, 155 (24.3%) were caries free. There were no statistically significant differences between caries levels and allele or genotype distributions in the total cohort. When the caries-affected group (n = 482) was stratified into low (decayed/missing/filled teeth = 1), moderate (2 ≤ decayed/missing/filled teeth ≤ 3) and high (decayed/missing/filled teeth ≥ 4) caries experience, allele and genotype frequencies were similar among all subgroups. CONCLUSIONS: The LTF 140A/G (exon 2, Lys/Arg) polymorphism was not associated with the susceptibility to or severity of dental caries in the Czech population.

Relationship between gingivitis severity, caries experience and orthodontic anomalies in 13-15 year-old adolescents in Brno, Czech Republic.

OBJECTIVES: The aim of the present cross-sectional study was to assess oral health in adolescents selected from the ELSPAC (European Longitudinal Study of Pregnancy and Childhood) Bmo group and complete thus the ELSPAC series of studies on child general health. MATERIAL AND METHODS: Randomly selected children from the ELSPAC group (n=780) were examined clinically for dental and periodontal status, dental plaque, dental calculus and orthodontic anomalies. The following clinical parameters were assessed: DMFT score and its components, gingival index (GI), plaque index (PI) and calculus index (CSI). GI, PI and CSI were recorded on selected teeth. The presence/absence of orthodontic anomalies and their severity were recorded. ANOVA test for quantitative and XZ2 test for qualitative parameters evaluation were used. RESULTS: Mean DMFT of the group was 2.82 (SE 0.36), share of caries-free children 25.4%. Mean GI index of the cohort was 0.204 (SE 0.011), grade 0 was found in 36.9% children, grade 1 in 43.0%, and grade 2 in 19.5%. Statistical significant associations (p < 0.05) were observed in GI and DMFT, GI and DT value, GI and severity of orthodontic anomaly; significant difference was found in GI of caries-free and treated children vs. treatment need and in PI value between children with gingivitis vs healthy ones. CONCLUSION: The results demonstrated a relatively high caries experience, low level of gingival inflammation and relation between GI and DMFT, particularly in D component, and between GI and orthodontic anomalies.

Comparison of dentine-resin interface in total-etch and self-etching adhesives using electron microscopy.

The important condition for the adhesive bond between dentine and composite filling is the change of dentine property from hydrophilic to hydrophobic. Substances able to accomplish this change, dentinal adhesives, have undergone complex development. Recently, the so-called self-etching adhesives have been formulated. The aim of the present paper was to compare the structural pattern of dentin/resin interface after the application of dentinal adhesives used in total- and self-etching technique. Dentinal adhesives Single bond, Prime bond, Prompt-L-pop Adper, and Xeno III were used. The former two belong to the total etch technique, the latter two to the self-etching technique. The dentin/resin interface was studied in transmission (TEM) and scanning (SEM) electron microscope. In TEM sixteen teeth were investigated, each adhesive was applied in four teeth. Under SEM forty teeth were studied, each adhesive was applied in ten teeth. The obtained results demonstrated that all the dentine adhesives studied were able to penetrate into dentinal tubules and to form a hybrid layer with the demineralized intertubular and peritubular dentine. There was no substantial difference in morphology of the dentine/resin interface between the techniques studied. Our results suggest that the hybrid layer function of all four adhesives might be of the same quality.

A histochemical study by light and electron microscopy of the distribution of dipeptidyl peptidase-IV activity in the human dental pulp.

This activity was demonstrated in blood vessels, fibroblast-like cells, odontoblasts and Schwann cells surrounding non-myelinated axons. It was present on both the luminal and abluminal plasma membrane of endothelial cells. The plasma membrane of fibroblast-like cells and their processes had patches of fine electron-dense end-product corresponding to DPP-IV activity, while the plasma membrane of odontoblasts was loaded with a consistent reaction product. DPP-IV activity in the non-myelin-forming Schwann cells was in the plasma membrane of the free surface in contact with the extracellular matrix as well as in the plasma membrane in close contact with the axolemma. The plasma membrane of Schwann cells producing myelin sheath had no positive reaction for DPP-IV. The DPP-IV activity in the plasma membrane of fibroblast-like cells and odontoblasts may be associated with fibronectin-mediated adhesion to collagen, whereas the membrane-bound DPP-IV activity in endothelium and non-myelin-forming Schwann cells may be involved in cleavage of neuropeptides of other biologically active peptides.

[Localization of beta-glucuronidase in human mouth mucosal epithelium]. / Lokalisation der beta-Glucuronidase im Mundschleimhautepithel des Menschen.

The authors investigated the activity of beta-glucuronidase in the mucous membrane of the alveolar process and in the buccal mucous membrane under light and electron microscopes. Demonstration of the enzyme was performed by means of a modification of the method of Hayashi. Under the light microscope enzymatic activity was demonstrated in both types of epithelium, particularly in the fibroblasts of connective tissue, higher activity being found in vascular walls, inflammatory infiltrates and particularly in macrophages. Findings in the epithelium were positive only in the stratum basale and the lower layers of the stratum spinosum. Submicroscopically activity of the enzyme was apparent in all layers of the epithelium, particularly in primary and secondary lysosomes and in cisternae of the granular endoplasmic reticulum, and only rarely in Golgi complex. There were only a few positive structures in the surface layers of the epithelium. Activity was lower in the buccal mucosa than in the alveolar epithelium. In the mucosa of the oral cavity the enzyme probably has a role in the degradation of proteoglycans.

Localization of some enzymes in the periodontium of the rat molar.

The authors studied alkaline and acid phosphatase, nonspecific esterase and NADH2 tetrazolium reductase localization in the periodontium of the rat molar. The activity of all enzymes studied remained preserved in spite of decalcification in EDTA. The activity of the enzymes was relatively high, the most intense reaction was observed, with the exception of alkaline phosphatase, in the gingival epithelium. In the junctional epithelium the reaction was less intense and decreased towards the end of the epithelial attachment. Only NADH2 tetrazolium reductase exhibited high activity in this region. The periodontal ligament displayed positive reaction in all enzymes studied with the exception of alkaline phosphatase, which was active only in the dentoalveolar ligament. The results of the present study indicate that highly active metabolic processes take place in the periodontium. The results and literature are discussed in the paper.

Lactobacillus spp. associated with early childhood caries.

A group of 69 lactobacilli was isolated from caries lesions and root canals of early childhood caries (ECC) affected children treated in the Department of Pedodontics (Children's Teaching Hospital, Brno, Czech Republic). Biochemical and physiological properties of all strains were characterized by API 50 CH kit and conventional tube tests. The rep-PCR fingerprinting with the (GTG)(5) primer was used for genotypic grouping of the isolates. The (GTG)(5)-PCR fingerprinting grouped all analyzed strains into a few clusters in nearly full agreement with phenotype identification results and clarified the taxonomic position of 13 biochemically unidentified strains. In total, 20 strains of Lactobacillus fermentum, 17 L. rhamnosus, 14 L. casei/paracasei, 7 L. gasseri, 7 L. salivarius and 4 L. plantarum were identified. Mixtures of two or even three Lactobacillus spp. were isolated from a few root canal content samples. Results obtained by biotyping and (GTG)(5)-PCR were generally comparable except for L. gasseri strains that were not biochemically identified. The (GTG)(5)-PCR fingerprinting was shown to be quicker, easier to perform and more reliable than biotyping. Our results imply this molecular method as a good tool for screening and identification of Lactobacillus spp. inhabiting dental plaque.

[Submicroscopic localization of endogenous peroxidase activity in the oral mucosal epithelium of man (author's transl)]. / Submikroskopische Lokalisation der endogenen Peroxidaseaktivität im Mundschleimhautepithel des Menschen.

Using electron microscopy, the authors localized endogenous peroxidase activity in the buccal mucosal and alveolar process epithelium. A positive reaction could be demonstrated in all epithelial layers. The number of positive structures was greatest in the spinous layer. The reaction product is of a granular nature and is localized in the microperoxysomes. The reaction of lipofuscin granules, lysosomes, and telolysosomes in the upper epithelial layers is considered to be of none enzymatic origin. The importance of endogenous peroxidase to tissue is discussed in detail.

[Histochemical observations on enzyme activity of the dental pulp following the orthodontic therapy]. / Histochemische Untersuchungen zur Enzymkativität der Zahnpulpa nach kieferorthopädischer Therapie.

The authors studied distribution of alkaline and acid phosphatases, non specific esterase and NADH2 tetrazolium reductase in the dental pulp of children treated by fix orthodontic appliances. All the enzymes studied exhibited positive reaction, the activity, however, was lower than in the controls, except of the alkaline phosphatase. The results of the study demonstrated that the forces between 60-200 g cannot be evaluated as biologically favorable.

An electron microscopic study of the human fetal mandibular periosteum.

The authors studied the submicroscopic structure of the human fetal periosteum. The mandible was in the 4 ..5th month of the fetal life formed of woven bone. The periosteum consisted of the cambial and fibrous layers. The cambial layer contained active osteoblasts, characterized by numerous endoplasmic reticulum profiles, flat cells with signs of osteolytic activity in their surroundings, and cells anchored to the bone matrix by their processes. From these cells the osteocytes developed. The submicroscopic structure of the young osteocytes was similar to that of osteoblasts. The fibrous layer contained numerous collagen fibres and fibroblasts, which were in the resting or active metabolic state. The results and literature are discussed in the paper.

[Light microscopic studies of pulp morphology following orthodontic therapy]. / Lichtmikroskopische Studien zur Pulpamorphologie nach kieferorthopädischer Therapie.

The authors studied the dental pulp morphology and distribution of acid and neutral mucopolysaccharides in teeth subjected to orthodontic therapy. The teeth were moved with a fixed appliance using forces of 60-200 g. Changes in the histological structure of the dental pulp followed the therapy. The number of collagen fibres increased; they were densely packed and formed thick bundles. A certain degree of hyalinization was also observed. The dental pulp cavity was narrowed by apposition of hard tissue deposits along the canal wall. Pulp stones and diffuse calcification were often encountered. The reaction of acid mucopolysaccharides was found to be very weak, sometimes even negative. The reaction of neutral mucopolysaccharides was not affected so markedly. The results of the paper suggest that changes induced in the dental pulp with fixed orthodontic appliances are irreversible and correspond to those of aging. These premature changes together with rapid hard tissue formation, may negatively influence endodontic treatment in the future.