Clinical and socio-behavioral correlates of tooth loss: a study of older adults in Tanzania

BACKGROUND: Focusing 50 year olds and above, this study assessed the frequency, extent and correlates of tooth loss due to various reasons. Frequency and correlates of posterior occluding support was also investigated. METHOD: A cross-sectional household survey was conducted in Pwani region and in Dar es Salaam in 2004/2005. One thousand and thirty-one subjects, mean age 62.9 years participated in a clinical examination and completed interviews. RESULTS: The prevalence of tooth loss due to any reason was 83.5 %, due to caries 63.4% and due to other reasons than caries, 32.5%. A total of 74.9% had reduced number of posterior occluding units. Compared to subjects having less than 5 teeth lost due to caries, those with 5 or more lost teeth were more likely to be females, having decayed teeth, confirming dental attendance and to be among the least poor residents. Compared to subjects who had lost less than 5 teeth due to reasons other than caries, those who had lost 5 or more teeth were more likely to be of higher age, having mobile teeth, being males, being very poor and to disconfirm dental attendance when having problems. Predictors of prevalence of tooth loss (1 or more lost tooth) due to various reasons and reduced number of occluding units followed similar patterns of relationships. CONCLUSION: The results are consistent with prevalence and extent of tooth loss due to caries and due to reasons other than caries being differently related to disease- and socio- behavioral risk indicators. Caries was the principle cause of tooth loss and molar teeth were the teeth most commonly lost

Effectiveness of the bucco-lingual technique within a school-based supervised toothbrushing program on preventing caries: a randomized controlled trial

Abstract Background Supervised toothbrushing programs using fluoride dentifrice have reduced caries increment. However there is no information about the effectiveness of the professional cross-brushing technique within a community intervention. The aim was to assess if the bucco-lingual technique can increase the effectiveness of a school-based supervised toothbrushing program on preventing caries. Methods A randomized double-blinded controlled community intervention trial to be analyzed at an individual level was conducted in a Brazilian low-income fluoridated area. Six preschools were randomly assigned to the test and control groups and 284 five-year-old children presenting at least one permanent molar with emerged/sound occlusal surface participated. In control group, oral health education and dental plaque dying followed by toothbrushing with fluoride dentifrice supervised directly by a dental assistant, was developed four times per year. At the remaining school days the children brushed their teeth under indirect supervising of the teachers. In test group, children also underwent a professional cross-brushing on surfaces of first permanent molar rendered by a specially trained dental assistant five times per year. Enamel and dentin caries were recorded on buccal, occlusal and lingual surfaces of permanent molars during 18-month follow-up. Exposure time of surfaces was calculated and incidence density ratio was estimated using Poisson regression model. Results Difference of 21.6 lesions per 1,000 children between control and test groups was observed. Among boys whose caries risk was higher compared to girls, incidence density was 50% lower in test group (p = 0.016). Conclusion Modified program was effective among the boys. It is licit to project a relevant effect in a larger period suggesting in a broader population substantial reduction of dental care needs. Trial registration ISRCTN18548869

Activity variations attending tungsten skarn formation, Pine Creek, California

An integrated geochemical analysis of the well-exposed Pine Creek, California tungsten skarn deposit has been undertaken to evaluate changes in chemical gradients across various lithologies. Thermodynamic calculations using available experimental and thermodynamic data allow limits to be assigned to the activities of important chemical components in the metasomatic environment. Quantifiable changes in “non-volatile” component activites (CaO, MgO, Al 2 O 3 , Fe 2 O 3 , WO 3 ) and in fugacities (O 2 , F 2 ) have been traced across the system. The activities of Al 2 O 3 , Fe 2 O 3 and WO 3 generally increase from the marble (<10 2 , <10 −6 , <10 −5 respectively), through the outer skarn zone and into the massive garnet skarn (10 −1.7±0.3 , 10 −3.4±0.4 , 10 −4.8±0.1 ) While CaO and MgO activities decrease for the same traverse from 10 −5 and 10 −2.1±1 respectively, to <10 −5.7 and <10 −3 . Calculated oxygen fugacities are 10 −23.5+1.0 at T =800 K (527° C), about one log unit below QFM, and more reducing than that required by Mt-Py-Po. The high variance of the garnet-pyroxene-quartz assemblages adds sufficient uncertainty to the calculated activities for individual specimens that only the large-scale trends survive the small-scale scatter. None of the chemical variables emerge as major independent or controlling factors for the mineralogy or phase compositions. Changes in the activity of one component may be offset by compensatory changes in another resulting in an environment that, while different from Pine Creek, could still host scheelite mineralization. Mass balance calculations indicate that the exposed endoskarn cannot have supplied the necessary chemical components to convert the country rock to skarn.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47341/1/410_2004_Article_BF00381557.pd

Targeting the X Chromosome during Spermatogenesis Induces Y Chromosome Transmission Ratio Distortion and Early Dominant Embryo Lethality in Anopheles gambiae

We have exploited the high selectivity of the homing endonuclease I-PpoI for the X-linked Anopheles gambiae 28S ribosomal genes to selectively target X chromosome carrying spermatozoa. Our data demonstrated that in heterozygous males, the expression of I-PpoI in the testes induced a strong bias toward Y chromosome–carrying spermatozoa. Notably, these male mosquitoes also induced complete early dominant embryo lethality in crosses with wild-type females. Morphological and molecular data indicated that all spermatozoa, irrespectively of the inheritance of the transgene, carried a substantial amount of I-PpoI protein that could attack the maternally inherited chromosome X of the embryo. Besides the obvious implications for implementing vector control measures, our data demonstrated the feasibility of generating synthetic sex distorters and revealed the intriguing possibility of manipulating maternally inherited genes using wild-type sperm cells carrying engineered endonucleases

Targeting the X Chromosome during Spermatogenesis Induces Y Chromosome Transmission Ratio Distortion and Early Dominant Embryo Lethality in Anopheles gambiae

We have exploited the high selectivity of the homing endonuclease I-PpoI for the X-linked Anopheles gambiae 28S ribosomal genes to selectively target X chromosome carrying spermatozoa. Our data demonstrated that in heterozygous males, the expression of I-PpoI in the testes induced a strong bias toward Y chromosome–carrying spermatozoa. Notably, these male mosquitoes also induced complete early dominant embryo lethality in crosses with wild-type females. Morphological and molecular data indicated that all spermatozoa, irrespectively of the inheritance of the transgene, carried a substantial amount of I-PpoI protein that could attack the maternally inherited chromosome X of the embryo. Besides the obvious implications for implementing vector control measures, our data demonstrated the feasibility of generating synthetic sex distorters and revealed the intriguing possibility of manipulating maternally inherited genes using wild-type sperm cells carrying engineered endonucleases