Strengthening the prevention of periodontal disease: the WHO approach

BACKGROUND: The aim of this paper is to provide an overview of the burden of periodontal disease in adult populations worldwide, to emphasize the essential risk factors common to periodontal disease and chronic diseases, to outline important new strategies for effective prevention of periodontal disease, and to inform about the role of the World Health Organization (WHO) in developing a national capacity for the prevention of disease. METHODS: Information about periodontal health status as measured by the Community Periodontal Index system is stored in the WHO Global Oral Health Data Bank. Updated information concerning WHO standard age groups was used to describe the prevalence rates of signs of periodontal disease, i.e., gingival bleeding, periodontal pocketing, and loss of attachment. RESULTS: Gingival bleeding is highly prevalent among adult populations in all regions of the world; advanced disease with deep periodontal pockets (> or =6 mm) affects approximately 10% to 15% of adults worldwide. The available evidence shows that important risk factors for periodontal disease relate to poor oral hygiene, tobacco use, excessive alcohol consumption, stress, and diabetes mellitus. Integrated preventive strategies based on the common risk factors approach are recommended for public health practice. CONCLUSIONS: The vast majority of countries need to establish a surveillance system for measuring progress in the control of periodontal disease and promotion of oral health. WHO has designed approaches for the integration of oral disease prevention within the prevention of non-communicable chronic diseases, and global strategies are currently being implemented in all regions of the world.     

Soluble tumour necrosis factor receptors in synovial fluids from temporomandibular joints with painful anterior disc displacement without reduction and osteoarthritis

The objective of this study was to detect soluble-form tumour necrosis factor receptors (sTNFRs) in temporomandibular joint (TMJ) synovial fluid aspirates, and to compare the sTNFR concentrations between painful anterior disc displacement without reduction and osteoarthritis (ADDwoR/OA) and asymptomatic TMJs.Synovial fluid was sampled from the superior TMJ cavity of 11 painful ADDwoR/OA cases (mean age: 36.9 years) and 10 asymptomatic females (mean age: 24.7 years) by diluted aspiration. The concentrations of sTNFR-I and -II in the synovial fluid were measured using human sTNFR-I and -II enzyme-linked immunosorbent assays. The total protein concentrations in synovial fluids were measured using a bicinchoninic acid protein assay kit. All data were normalised to the total protein concentration of each sample.Two-way factorial analysis of variance and post hoc multiple comparison revealed that: (1). mean normalised sTNFR-I and -II concentrations were higher in TMJ synovial aspirates from ADDwoR/OA patients than from healthy controls; (2). in the ADDwoR/OA patients and the healthy controls, the sTNFR-I concentration in TMJ synovial aspirates was higher than the sTNFR-II concentration; and (3). high TMJ synovial aspirate sTNFR-II seemed to be associated with less TMJ pain and a less restricted range of mouth opening in the ADDwoR/OA patients.The concentrations of sTNFRs in TMJ synovial fluid are higher in the presence of painful ADDwoR/OA, which could modulate intracapsular inflammation.     

Asymmetry of the face in orthodontic patients

OBJECTIVE: To investigate the laterality of the normal asymmetry of the human face, examining differences in laterality in relation to sex, growth stage, and skeletal classification. MATERIALS AND METHODS: A total of 1800 Japanese subjects (651 males and 1149 females; mean age, 15 years 3 months; range, 4 years 2 months to 59 years 11 months) were selected. Individuals in the sample were categorized according to sex, one of three growth stages, and one of three skeletal patterns. Differences in length between distances from the points at which ear rods were inserted to the facial midline and the perpendicular distance from the soft-tissue menton to the facial midline were measured on a frontal facial photograph. Subjects with a discrepancy of more than 3 standard deviations of the measurement error were categorized as having left- or right-sided laterality. RESULTS: Of subjects with facial asymmetry, 79.7% had a wider right hemiface, and 79.3% of those with chin deviation had left-sided laterality. These tendencies were independent of sex, age, or skeletal jaw relationships. In this regard, during pubertal growth, the proportion of subjects with wider right hemiface decreased (P < .0001), whereas the proportion of those with a wider left hemiface increased (P < .01), despite a consistent tendency for right-sided dominance. CONCLUSION: These results suggest that laterality in the normal asymmetry of the face, which is consistently found in humans, is likely to be a hereditary rather than an acquired trait.     

Effect of water temperature on the fit of provisional crown margins during polymerization

STATEMENT OF PROBLEM: When fabricating a provisional crown with the direct technique, dentists are concerned with margin discrepancies that result from polymerization shrinkage. PURPOSE: This in vitro study examined the effect of water temperature on the fit of provisional crown margins during resin polymerization. MATERIAL AND METHODS: The experiment was designed to simulate a direct technique to fabricate provisional crowns. After mixing autopolymerizing methyl methacrylate resin, the material was placed in a preformed polycarbonate crown. The crown was seated on a prepared premolar-shaped die with a shoulder margin. After 1 minute and 50 seconds, the crown was removed and polymerization was continued under the following conditions: 20 degrees C air, and water at 0 degrees C, 10 degrees C, 20 degrees C, 30 degrees C, 40 degrees C, 60 degrees C, and 80 degrees C. Six minutes after polymerization, the crown was trimmed and reseated on the die. Discrepancy of crown margin was measured with a 3-dimensional digitizer. RESULTS: Margin discrepancy varied with the condition during resin-polymerization (ANOVA, P <.001). The crowns polymerized in 20 degrees C and 30 degrees C water revealed the best margin fit, showing 3 times more accurate margin fit than those polymerized in 20 degrees C air (Bonferroni/Dunn procedure, P <.01). CONCLUSION: Conditions during resin polymerization were significant factors that affected margin fit of provisional crowns using the direct technique. Water temperatures of 20 degrees C and 30 degrees C produced the best fit at the margin of the provisional crown.     

Immunohistochemical study of hard tissue formation in the rat pulp cavity after tooth replantation

While mineralized tissue is formed in the pulp cavity after tooth replantation or transplantation, little is known of this hard tissue formation. Therefore, we conducted histological and immunohistochemical evaluations of hard tissue formed in the pulp of rat maxillary molars after tooth replantation. At 5 days after replantation, degenerated odontoblasts were lining the pulp cavity. At 14 days, dentin- or bone-like tissue was present in the pulp cavity. Immunoreactivity for osteopontin (OPN) and bone sialoprotein (BSP) was strong in the bone-like tissue, but weak in the dentin-like tissue. Conversely, dentin sialoprotein (DSP) was localized in the dentin-like tissue, but not in the bone-like tissue. Cells positive for BMP4, Smad4, Runx2, and Osterix were found around the blood vessels of the root apex at 5 days. At 14 days, these cells were also localized around the bone-like tissue. Cells expressing alpha-smooth muscle actin (SMA) were seen around the newly formed bone-like tissue, whereas no such cells were found around the newly formed dentin-like tissue. In an experiment involving the transplantation of a green fluorescent protein (GFP)-transgenic rat tooth into a wild-type rat tooth socket, GFP-positive cells were detected on the surface of the bone-like tissue and over all dentin-like tissue. These results indicate that the original pulp cells had the ability to differentiate into osteoblast-like cells as well as into odontoblast-like cells.     

Plasma-based fluorine ion implantation into dental materials for inhibition of bacterial adhesion

The aims of this study were to evaluate the fluorine depth profiles of pure titanium (Ti), stainless steel (SUS), and polymethyl methacrylate (PMMA) modified by plasma-based fluorine ion implantation and the effects of fluorine ion implantation on contact angle, fluoride ion release, and S. mutans adhesion. Fluorine-based gases used were Ar+F2 and CF4. By means of SIMS, it was found that the peak count of PMMA was the lowest while that of Ti was the highest. Then, up to one minute after Ar sputtering, the presence of fluorine and chromic fluoride could be detected by XPS in the surface and subsurface layer. As for the effects of using CF4 gas for fluorine ion implantation into SUS substrate, the results were: contact angle was significantly increased; no fluoride ion release was detected; antibacterial activity was significantly increased while initial adhesion was decreased. These findings thus indicated that plasma-based fluorine ion implantation into SUS with CF4 gas provided surface antibacterial activity which was useful in inhibiting bacterial adhesion.     

Involvement of angiotensin II type 1 receptors in interleukin-1β-induced interleukin-6 production in human gingival fibroblasts

The renin-angiotensin system is thought to be involved in inflammatory processes such as periodontitis. However, its precise role is still unclear. Therefore, in the present study the expression of the angiotensin II type 1 receptor (AT1R) was investigated in inflamed human gingival tissue, and the possible involvement of the AT1R in interleukin-1β (IL-1β)-induced interleukin-6 (IL-6) production by cultured human gingival fibroblasts (HGFs) was also studied. Immunohistochemical staining revealed that inflammatory cells and fibroblast-like cells were positive for the AT1R. However, in healthy gingival tissue, AT1R staining was very weak. The levels of AT1R mRNA and AT1R protein increased in HGFs after stimulation with IL-1β. The levels of IL-1β-induced IL6 mRNA and IL-6 protein were significantly reduced in AT1R gene-silenced HGFs compared with control HGFs. The data suggest that the AT1R may be involved in the regulation of gingival inflammation by modulating IL-1β-induced IL-6 production in HGFs.