Purification and characterization of galactosephilic component present on the cell surfaces of Streptococcus sanguis ATCC 10557

Previous studies have indicated that a galactosephilic component present on the bacterial cell surfaces of Streptococcus sanguis ATCC 10557 may be responsible for the salivary glycoprotein-mediated binding of the cells. The purpose of this study was to investigate the purification and characterization of galactosephilic cell surface component from S. sanguis ATCC 10557. A galactosephilic component involving fibrils on the cell surfaces was isolated by the techniques of freezing and thawing, and purified by an affinity chromatography on beta-D-galactose binding-Bio-Gel P-2 followed by gel filtrations on Bio-Gel P-150 and on Bio-Gel P-30. Both disk gel electrophoresis and sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that the purified product was homogeneous. The isoelectric point of the purified sample was 8.5 to 9.0. Treatment of the purified sample with pronase E reduced remarkably either the hemagglutinating activity or the precipitation reaction with proline-rich glycoprotein in human parotid saliva, suggesting that the active site may be present on the peptide moieties. When sugar specificity was examined by hemagglutination-inhibition test, D-galactose was the strongest inhibitor. The results of this study suggest that the galactosephilic component may be a bacterial lectin.     

Periodontal disease in juvenile and adult diabetic patients: a review of the literature

Epidemiologic studies have suggested that the severity of periodontitis is greater in juvenile and adult onset diabetes. In juvenile diabetic patients, the periodontal disease seems to be initiated around puberty and progresses by age. Reviewing the medical literature indicates a similar age of onset for known systemic complications resulting from diabetes. Angiopathy, abnormal collagen metabolism, abnormal PMN function, and altered sulcular microbial flora have been found to be closely associated with the severity of periodontitis in diabetic patients. The association between abnormal neutrophil function and severity of periodontal disease in diabetic patients provides an opportunity for examining the role of neutrophil in periodontal disease. Future investigation in the function of sulcular PMN may shed light on the complex mechanism of periodontal disease.     

The rationale for the indication and design off the MOD inlay

Modern preventive measures enable an occlusion based approach in the design of an MOD inlay. Treatment planning should require control of the caries problem and institution of sound oral hygiene before any permanent cast restoration is provided. Because of stress developing from occlusal forces being translated into a wedge action fracture of the crown weakened by cavity preparation is enhanced. When inlay restorations are indicated preference should be given to partial coverage of the crown.     

Human enamel erosion in constant composition citric acid solutions as a function of degree of saturation with respect to hydroxyapatite

The objective of this study was to investigate human enamel erosion under constant composition conditions, as a function of solution degree of saturation (DS) with respect to hydroxyapatite. The experimental conditions were relevant to the initial stages of enamel erosion by soft drinks. Nanoindentation was used to compare enamel surface softening caused by a control mineral water and two citric acid solutions with DS = 0.000 and DS = 0.032, both having pH 3.30. Enamel hardness and reduced elastic modulus were measured after 0, 30, 60, 120, 300 and 600 s exposure. A statistically significant change in enamel hardness was detected after 30 s exposure to both citric acid solutions, indicating that nanoindentation is extremely sensitive to the initial stages of erosion. There was a statistically significant difference between the mechanical properties of enamel exposed to the two citric acid solutions after 30, 60 and 120 s. At these times, the solution with DS = 0.000 caused twice as much enamel softening as that with DS = 0.032. This demonstrates that it may be possible to design a soft drink with a low erosive potential and a good taste by a small change in DS, at a typical drink pH.     

Skeletal effects of bite jumping therapy on the mandible - removable vs. fixed functional appliances

AUTHORS: Shen G, Hagg U, Darendeliler MA. OBJECTIVE: Based on an extensive review of the literature, the aim of this study was to explore the mainstream consensus on the controversial topic of whether the bite jumping treatment could enhance mandibular growth. DESIGN: The data for removable and fixed functional appliances were respectively comprehended and analyzed with regard to their attributes in mandibular growth modification. Furthermore, numerous reported findings were assessed by relating them to some important factors influencing the effects of bite jumping, such as treatment timing, treatment duration and post-treatment follow-up, to allow for a more objective and accurate evaluation. RESULTS: The key differences between removable and fixed appliances are working hours (intermittent vs. continuous), length of treatment time (long vs. short), optimal treatment timing (before puberty growth vs. at or after puberty spurt), and mode of bite-jumping (considerable vertical opening vs. limited vertical opening). These different features lead to different treatment effects on mandibular and TMJ growth, such as the intensity of possibly increased growth (clinically less significant vs. significant), the direction of enhanced growth (vertical vs. horizontal), and the stability of treatment changes (unstable vs. stable). The short-term or long-term post-treatment relapse mainly relates to the rebound of dental position. CONCLUSION: The immediate effects of bite jumping functional appliances on the mandibular growth enhancement are convincing during actual treatment. This extra gain of growth might be sustainable during the short-term and long-term post-treatment period.     

The differentiation profile of the epithelium of the human lip

The aim of this study was to analyse the immunohistochemical differentiation profile of the stratified squamous epithelium of the adult human lip. Full-thickness lower lips taken from 31 cadavers were analysed. Sections were stained with haematoxylin and eosin, periodic acid-Schiff (PAS), cytokeratins (CK), loricrin, involucrin, profilaggrin and filaggrin. The stratified squamous epithelium covering the lip could be divided into: (i) appendage-bearing, orthokeratinised epidermis; (ii) orthokeratinised vermilion which had a more prominent rete pattern than the epidermis; (iii) parakeratinised, PAS-positive intermediate zone; and (iv) non- or parakeratinised labial mucosal epithelium. Epithelial thickness increased gradually from the skin to the mucosal aspect. The CK pattern changed across the intermediate zone, with gradual loss of CK 1 and 10 from the skin, and CK 4, 13 and 19 from the mucosal, aspect. CK 5 and 14 were consistently expressed basally, and variably expressed suprabasally. Apart from labelling Merkel cells, CK 8, 18 and 20 were negative. Involucrin, which was present at all sites, was restricted to the stratum granulosum in skin, but extended into the stratum spinosum, and gradually into parabasal keratinocytes, across the vermilion and mucosa. Loricrin, profilaggrin and filaggrin were present in the stratum granulosum of orthokeratinised sites, but expression was abruptly lost at the junction between the vermilion and the intermediate zone. In conclusion, the phenotype of the stratified squamous epithelium covering the lip changes at, or across, the intermediate zone of the adult vermilion. It is possible that changes in the composition of the stratified squamous epithelium affect the colour of the vermilion.     

Effects of sports drinks and other beverages on dental enamel

A high percentage of people consume soft drinks that contain sugar or artificial sweeteners, flavorings, and various additives. The popularity of sports (energy) drinks is growing and this pilot study compares enamel dissolution in these and a variety of other beverages. Enamel blocks (approximately 7.0 x 5.0 x 2.5 mm) were sectioned from sound extracted human premolars and molars and measured, weighed, and immersed in the selected beverages for a total of 14 days. The pH of all beverages was measured. The enamel sections were weighed at regular intervals throughout the immersion period with the solutions being changed daily; all studies were performed in duplicate. The data were subjected to one-way ANOVA with post hoc Scheffe testing. Enamel dissolution occurred in all of the tested beverages, with far greater attack occurring in flavored and energy (sports) drinks than previously noted for water and cola drinks. No correlation was found between enamel dissolution and beverage pH. Non-cola drinks, commercial lemonades, and energy/sports drinks showed the most aggressive dissolution effect on dental enamel. Reduced residence times of beverages in the mouth by salivary clearance or rinsing would appear to be beneficial.