Calculus revisited

Although there is no doubt that gingivitis can develop in the absence of supragingival calculus, it is not clear to what extent the presence of mineralized deposit enhances gingival inflammation. Partial inhibition of plaque mineralization can be accomplished by chemical agents, but there has been no demonstration in humans of a reduction in gingivitis. It remains to be established what level of inhibition (if any) is required to have more than a cosmetic effect. Since the accepted scenario is that apical growth of supragingival plaque precedes the formation of subgingival calculus, there is no longer an issue of whether subgingival calculus is the cause or the result of periodontal disease. Subgingival mineralization results from the interaction of subgingival plaque with the influx of mineral salts that is part of the serum transudate and inflammatory exudate. This chronology, however, should not be the basis for relegating calculus to the ash heap. Morphologic and analytical studies point to the porosity of calculus and retention of bacterial antigens and the presence of readily available toxic stimulators of bone resorption. When coupled with the increased build up of plaque on the surface of the calculus, the combination has the potential for extending (beyond that of plaque alone) the radius of destruction and the rate of displacement of the adjacent junctional epithelium. The centrality of thorough scaling and root planing in the successful maintenance of periodontal health supports the view that subgingival calculus contributes significantly to the chronicity and progression of the disease, even if it can no longer be considered as responsible for initiation.     

Evaluation of 2-phosphono-butane 1,2,4 tricarboxylate as a crystal growth inhibitor in vitro and in vivo

The inhibitory activity of 2-phosphono-butane 1,2,4 tricarboxylic acid (PBTA) in the formation of hydroxyapatite (HA) was studied in vitro and in vivo. PBTA, at 4 ppm, inhibited the spontaneous formation of HA in vitro from a supersaturated solution. PBTA, at 2 ppm, completely inhibited the crystal growth of HA; at lower concentrations, a direct relationship was found between the reduction of the initial precipitation rates and PBTA concentrations in the solution. The effects of PBTA on human dental enamel in vitro were also evaluated at pH 5.0 and 7.5. Equimolar levels of EDTA served as the controls. In comparison with EDTA, the dissolution of enamel induced by PBTA was negligible. One percent solution of PBTA was evaluated in a rat calculus assay. In comparison with a placebo solution, it significantly (p = 0.05) reduced calculus formation when applied topically. It was also tested against calculus formation in beagle dogs. A topical application once a day of a 1% solution at pH 7.0 reduced calculus formation by 84% for 16 weeks. Analysis of these data suggests that the agent effectively reduces calculus formation in vivo.     

Xerophthalmia, protein-calorie malnutrition, and infections in children.

All children with evidence of xerophthalmia who were admitted to an inpatient facility for treatment of severe protein-calorie malnutrition and its complications were compared to other inpatients with severe PCM but free from signs or symptoms of vitamin A deficiency. Xerophthalmic inpatients were older and had more severe hypoproteinemia than inpatients without eye signs, and were more undernourished by anthropometric criteria than a comparison group matched for age, sex, and type of PCM. Children with more severe eye lesions were more retarded in growth than those with minimal ocular signs. All inpatients had high rates of bacterial infections, regardless of their vitamin status. However, xerophthalmic children had a highly significant increase in the rate of positive urine cultures. Mortality rates were similar in all study groups.     

Infections associated with severe protein-calorie malnutrition in hospitalized infants and children

One hundred Bangladeshi children admitted to hospital for treatment of severe protein-calorie malnutrition were systematically evaluated for the presence of infections. Ninety percent of children had some evidence of systemic infection at the time of admission and 75% had pneumonia, bacteruria, diarrhea in association with a known enteric pathogen, bacteremia, meningitis, or more than one of these major infections. Forty-nine percent of patients had pneumonia, including 14% of admissions with clinical evidence of pulmonary tuberculosis. Forty-three percent of admissions had diarrhea and 40% had evidence of enteric infections, most commonly shigellae or rotavirus. Bacteruria occurred in 30% of admissions, but bacteremia was identified in only 2% of patients initially. The prevalence of intestinal parasites increased with age, both among inpatients and comparison subjects with less severe grades of malnutrition. There did not appear to be important differences in the parasite loads or prevalences between the 2 groups.Twenty-one inpatients died; deaths were more common in younger children. The cause of death was most frequently related to infections. The identification and appropriate treatment of infections must be considered a major component of the rehabilitation of severely malnourished children.     

Colonization of the oropharynx with Gram-negative bacilli in children with severe protein-calorie malnutrition

Oral pharyngeal isolation of Gram-negative bacteria was compared in four groups of Bengali children; acutely ill, severely malnourished outpatients swabbed on hospital admission; ill but less severely malnourished outpatients from the same area as the malnourished children; orphans also less severely malnourished but not acutely ill; and well controls drawn from a priviledged socioeconomic group. The expected weight for height percentage (National Center Health Statistics/Center for Disease Control median) of the four groups was respectively 67, 91, 97, and 97%. Isolation of Gram-negative bacteria from 74 of 87 (85%) severely malnourished children was significantly greater (p less than 0.01) compared to 43 of 113 (38%) outpatients, to 20 of 93 (22%) orphans, and to five of 51 (10%) controls. A total of 71 malnourished children under 5 yr of age (90%) had higher rates of Gram-negative throat colonization than did 16 older children (63%) (p less than 0.01). Thus there was an increased rate of Gram-negative colonization in severely malnourished children especially among the younger age group. In the subset of ill children, Gram-negative pharyngeal colonization was significantly associated inversely with nutritional indices and age. The high rate of such carriage may be partly responsible for the increased susceptibility of Gram-negative infection demonstrated in these children.     

Sociodemographic Factors Associated With Tobacco Smoking Among Intermediate and Secondary School Students in Jazan Region of Saudi Arabia

ABSTRACT

Background: The objectives of this study were to (i) determine the prevalence of and characteristics associated with tobacco smoking; (ii) identify the factors associated with tobacco smoking; and (iii) evaluate the association between tobacco smoking and khat chewing among intermediate and secondary school students in Jazan Region, Saudi Arabia. Methods: A cross-sectional study was conducted with a representative sample (N = 4100) of intermediate and secondary school students in Jazan Region. The data were collected using a pretested modified version of the global youth tobacco survey questionnaire. Results: A total of 3923 students from 72 intermediate and secondary schools for males and females in Jazan Region, Saudi Arabia, were included in this study. The ever having smoked prevalence was 17.3%, and the current smoking prevalence was 10.7%. The most important independent predictors of smoking were academic performance (odds ratio [OR]: 5.32), having friends who used khat (OR: 3.23), and having friends who used tobacco (OR: 2.88). Conclusions: Understanding the factors and predictors associated with tobacco use are crucial to identifying high-risk groups to design tobacco prevention and control programs. For the first time, a strong and statistically significant association was identified between tobacco smoking and khat chewing among intermediate and secondary school students in Jazan Region. Because the use of khat is increasingly spreading outside of its traditional areas to Europe and America, this finding may have an important impact on tobacco control efforts internationally.     

Glucose indices, frank and undetected diabetes in relation to hypertension and anthropometry in a South Indian rural population

Diabetes has emerged as one of the world's biggest health problems and its prevalence is increasing at an alarming rate. This study was conducted to find out the magnitude of frank and undetected diabetes mellitus, including impaired glucose tolerance (IGT) among persons in rural Karnataka, and its relationship with associated risk factors like hypertension and anthropometry. This was a population-based, cross-sectional study on 1370 participants in the field practice area of KBN Medical College, conducted from April 2009 to March, 2010. Diabetes mellitus was noted among 19.78% of the participants, with an additional 12.04% with impaired glucose tolerance. Hypertension observed among participants with diabetes and impaired glucose tolerance was 65.13 and 53.94%, respectively. Effective primary prevention strategies have to be intensified among high-risk population groups, to promote awareness through behavior change communication.