Periodontal health in various ethnic groups in Israel

The periodontal status of approximately 5,000 subjects belonging to nine ethnic groups of Oriental origin, aged four years and above and living in villages in Israel, was investigated. The severity of periodontal involvement of a group was found to be similar whether expressed as gingivitis in childhood or as destructive periodontal disease in adolescence and adult life. Gingivitis reached its peak at the age of 10 to 11 years and then tended to level off or even decline. The periodontal index (PI) and gingival recession rate (GRR) both formed straight line graphs between the ages of 17 and 55+. The incidence and prevalence of periodontal disease were almost uniformly higher in males than in females. In the populations investigated in the present study, it appears unwarranted to attribute this difference to differences in attitude to oral health and hygiene between the sexes. The possibility that habitual chewing of the leaves of Catha edulis is a causative factor in the exceptionally high rates of periodontal disease in Yemenite males is discussed. The periodontal health of the best groups was inferior to that of white Americans, and of the same order as that of American Negroes and the inhabitants of Lebanon and Chile. The most severe degree of involvement was comparable to findings in South-East Asia, and occurred in people who had immigrated from India.     

Image layer characteristics of the PC 1000 (mark II)

The objective of this study was to investigate empirically the image layer characteristics of the PC 1000 Mark II. Radiographs were taken of a lead resolution grid positioned at 1 mm increments along angular intervals of the projected x-ray beam. The receptor was T-Mat G film combined with Lanex Regular Screens. The path of the effective rotation center was determined using a film positioned horizontally at right angles to the slit beam. The vertical magnification factor, horizontal magnification and Distortion Index, corrected for the position of the tomographic layer, were calculated using a reference object placed at various resolution limits of the image layer. The beam projection angle was compared to the average dental arch shape and proximal contact angle. The maximum resolution observed at the central plane of the image layer was 4 lp · mm⁻¹. The image layer width at the 1.5 lp · mm⁻¹ resolution contour varied from 12 mm anteriorly to 41 mm posteriorly. The vertical magnification factor within the image layer showed a linear increase along the beam path from 1.21 to 1.36. The horizontal magnification varied from 1.07 to 1.71, and the Distortion Index from 0.85 to 1.15. The beam projection angulations to the average arch shape ranged from 90° anteriorly to 115° in the premolar segments and 105° in the molar regions. The empirically derived image layer of the PC 1000 Mark II conforms to the shape of the average dental arch and that found using MTF analysis. The spatial resolution attained using a standard receptor is within the acceptable range.     

Contribution of individual drugs to gingival overgrowth in adult and juvenile renal transplant patients treated with multiple therapy

Abstract. Drug regimens for transplantation often consist of multiple therapeutic agents and may result in drug-induced gingival overgrowth (DIGO). The aim of this study was to investigate the contribution of individual drugs in renal transplant patients. 147 adults (19–84 years) and 60 juveniles (3–18 years) were scored for DIGO and other clinical variables. Duration of treatment, dosage of drugs per kg body weight and serum cyclosporin levels were recorded. 44% of adults and 27% of children had DIGO. All patients were receiving prednisolone. More adults than children were administered cyclosporin, the reverse was true of azathioprine ( P 0.01), Explanatory models were evaluated by stepwise ordinal polynomial logistic regression. Statistically significant explanation ( P 0.05) of DIGO was afforded by prednisolone, nifedipine and azathioprine concentrations in adults and by cyclosporin, nifedipine and azathioprine concentrations in juveniles. Prednisolone and azathioprine were inversely related to the degree of DIGO. Plaque and irregularity scores, lip coverage and mouthbreathing status showed significant additional explanation in adults, replacing nifedipine and azathioprine in the final model. Irregularity was additionally explanatory in children, but no other clinical variables. A larger proportion of the variance of DIGO was explained by the available variables in children than in adults (pseudo r ²=0.50 versus 0.25). The degree of DIGO in renal transplant patients is influenced by the dosage of a number of individual components of multiple drug therapy independently of the presence of local clinical factors.     

A new ultrasensitive chemiluminescent assay for the site-specific quantification of alkaline phosphatase in gingival crevicular fluid

The search for markers of periodontal disease activity and progression has accelerated over the last decade, in an effort to replace existing subjective clinical measures of periodontal health status. Research is being aimed at establishing more objective and quantitative methodology, capable of rapid diagnosis prior to the appearance of clinical signs of destructive disease. Such tests need to be sensitive enough to evaluate individual periodontal sites in health as well as disease states. We report the development of a new chemiluminescent assay for the enzyme alkaline phosphatase, that is capable of quantifying the enzyme in sub-microliter volumes of gingival crevicular fluid and serum. The technique will measure alkaline phosphatase (ALP) whilst immobilised on paper strips, without the need for an elution stage. It is simple, versatile and amenable to chair-side use. We discuss in detail the assay procedure and have examined levels of ALP in 11 adult volunteers with clinically healthy periodontal tissues. The mean ALP concentration was 2135 IU/L for GCF and 183 IU/L for serum, a 12-fold difference. There also appeared to be an "oral pattern" of enzyme distribution in healthy periodontal sites, with levels being higher in the anterior region of the mouth and highest in the lower anterior region.     

Brushing with a potassium nitrate dentifrice to reduce bleaching sensitivity

OBJECTIVE: This research systematically evaluated the use of a clinically proven desensitizing dentifrice prior to a bleaching regimen in a randomized, multi-center, parallel group, open label clinical study following Good Clinical Practice guidelines. METHODOLOGY: Fourteen dental offices in West Palm Beach, Florida participated in the study during April/May 2004. Fourteen days prior to bleaching, impressions and oral soft tissue assessments were performed, and patients were randomized to either a KNO3 plus fluoride dentifrice (Sensodyne Fresh Mint), or a standard fluoride dentifrice (Crest Regular), brushing 2x per day. On Day 14, patients returned to the dental office for their custom tray and the dispensation of a bleaching kit (Day White Excel 3; 9.5% hydrogen peroxide and KNO3). This was used daily according to the manufacturer's instructions for 30 minutes, and normal oral hygiene continued to be performed using the assigned toothbrush and dentifrice, brushing 2x per day. At the end of each bleaching day, patients answered diary questions about the occurrence and intensity of sensitivity. At the conclusion of the 14-day bleaching period (Day 28), patients returned to their dental office for re-examination, returning all products and diaries. Within seven days of completing the study, patients answered a telephone patient satisfaction survey. RESULTS: A total of 202 patients in fourteen (14) dental offices completed all aspects of the study and were used for the analysis. The professionally dispensed bleaching product provided an improvement of approximately 4.4 Vita shades, regardless of whether it was used with the KNO3 plus fluoride (Sensodyne) or a standard fluoride (Crest) dentifrice. The patient perception of increased sensitivity caused by the bleaching treatment was low but measurable. In the first week of the bleaching, significantly more patients using the KNO3 plus fluoride dentifrice were free from sensitivity (58%) than the standard fluoride dentifrice group (42%). During the 14-day bleaching treatment period, the KNO3 dentifrice patients experienced significantly more "sensitivity free days" (average = 10.1) compared to the standard fluoride dentifrice group (average = 8.6). CONCLUSION: The use of the KNO3 plus fluoride dentifrice (Sensodyne), two weeks prior to and throughout bleaching, may be a useful adjunct for the management of sensitivity caused by professionally dispensed bleaching products. With the bleaching-induced tooth sensitivity, those patients in the KNO3 plus fluoride toothpaste group were significantly more satisfied with their whitening experience and willing to repeat the bleaching treatment.     

Vegetarian children and dental erosion

Background . There have been recent changes in teenage lifestyle and diet. The increasing consumption of soft drinks and foods containing significant acidic components may play a role in the development of dental erosion.
Objective . The aims of this investigation were firstly, to assess the prevalence of vegetarian children in a cluster random sample of 14-year-old children in Birmingham, United Kingdom. Secondly, to determine the prevalence of dental erosion in these children, and thirdly, to see if there were any differences between vegetarian and non-vegetarian children in the prevalence of dental erosion and dietary intake.
Design . A cluster random sample of 418 14-year-old children (209 males and 209 females) were examined from 12 different schools in Birmingham, United Kingdom; a dietary questionnaire was completed and the levels of tooth wear were recorded using a modification of the (TWI) index. All data were analysed using SPSS with t -test and Chi-square analysis. Significance was accepted at the P < 0·05 level.
Results . The results showed that 10% of the children were vegetarian; 52% of them had low dental erosion and 48% moderate dental erosion. Statistically there were no significant differences between vegetarian and non-vegetarian children in the prevalence of erosion; however, there were significant differences in some food and drink consumption.
Conclusions . It was concluded that dental erosion is common in teenage children, but there were no significant differences in prevalence between vegetarian and non-vegetarian children.     

Detection and possible biological role of chondroitinase and heparitinase enzymes produced by Porphyromonas gingivalis W50

Gingival crevicular fluid levels of the glycosaminoglycan (GAG) chondroitin-4-sulphate (C-4-S) have received increased attention as potential indicators of periodontal tissue turnover. However, little is known about the relationship between crevicular fluid connective tissue metabolites and microbial factors. In this study Porphyromonas gingivalis , a periodontopathogen, was investigated for its ability to degrade the GAGs C-4-S, dermatan sulphate (DS) and heparan sulphate (HS) in vitro . The effect of P. gingivalis extracts on the proteoglycans (PG) derived from human gingiva were also investigated. The presence of chondroitinase and heparitinase eliminase enzymes were identified from the vesicle fraction of P. gingivalis W50. These enzymes were extracted from the vesicle fraction by a differential centrifugation technique and partially purified by non-denaturing gel filtration chromatography which revealed heparitinase enzyme peaks at 200 and 150 kDa and chondroitinase at 70 kDa. Gingival proteoglycans for use as substrates were purified using 4 M guanidinium chloride extraction and anion exchange chromatography; these proteoglycans contained 48% DS, 27% C-4-S and 13% HS P. gingivalis chondroitinase and heparitinase enzymes were capable of the degradation of C-4-S and HS but not DS GAGs. The presence of chondroitinase enzymes produced by P. gingivalis may influence levels of connective tissue metabolites in crevicular fluid. Furthermore these enzymes, particularly the heparitinase, may be involved in the initial permeation of the gingival epithelium, permitting the ingress of further microbial virulence factors.     

Effect of adoptive transfer of antigen-specific B cells on periodontal bone resorption

BACKGROUND AND OBJECTIVES: Host immune responses to periodontal pathogens have been considered to contribute to the alveolar bone destruction in periodontitis. However, the role of B lymphocytes in the pathogenesis of periodontal bone loss is not clear. METHODS: We examined the effect of adoptive transfer of antigen-specific B cells from rat spleens on experimental periodontal bone resorption. Donor rats were immunized intraperitoneally (i.p.) with formalin-killed Actinobacillus actinomycetemcomitans. Antigen-specific B cells were prepared from splenocytes by first binding CD43(+) cells to Petri dishes coated with anti-CD43 antibody to remove T cells, and non-binding cells were passed through a nylon wool column to deplete accessory cells. The retained cells were then collected and bound to A. actinomycetemcomitans-coated Petri dishes for enrichment of A. actinomycetemcomitans-binding B cells (AAB). A. actinomycetemcomitans non-binding B cells (ANB) and B cells from non-immunized donor rats (NIB) were also collected from these procedures. Each type of B cell was injected into a group of recipient rats that were then orally infected with live A. actinomycetemcomitans. RESULTS: At termination, the antibody levels to A. actinomycetemcomitans in serum and gingival wash fluids were significantly higher in the recipients transferred with AAB when compared to the recipients transferred with ANB or NIB. A markedly elevated number of antibody-forming cells were observed in the spleens of the recipients transferred with AAB, and these recipient rats also exhibited significantly increased bone resorption when compared to the other groups. CONCLUSIONS: It is suggested that B cells can contribute to periodontal bone resorption and that antigen-triggering of B cells is required for the bone resorption.     

Parachute use to prevent death and major trauma related to gravitational challenge: systematic review of randomised controlled trials

OBJECTIVES: To determine whether parachutes are effective in preventing major trauma related to gravitational challenge. Design Systematic review of randomised controlled trials. DATA SOURCES: Medline, Web of Science, Embase, and the Cochrane Library databases; appropriate internet sites and citation lists. STUDY SELECTION: Studies showing the effects of using a parachute during free fall. MAIN OUTCOME MEASURE: Death or major trauma, defined as an injury severity score > 15. RESULTS: We were unable to identify any randomised controlled trials of parachute intervention. CONCLUSIONS: As with many interventions intended to prevent ill health, the effectiveness of parachutes has not been subjected to rigorous evaluation by using randomised controlled trials. Advocates of evidence based medicine have criticised the adoption of interventions evaluated by using only observational data. We think that everyone might benefit if the most radical protagonists of evidence based medicine organised and participated in a double blind, randomised, placebo controlled, crossover trial of the parachute.