Caries experience as predictor for caries incidence

The caries increment (filled surfaces) from the ages 7 to 15 years were compared in children with three or fewer (low prevalence group) or eight or more filled surfaces (high prevalence group) at the age of 8. The children participated in a fortnightly fluoride mouthrinsing program (10 ml of 0.2% NaF). Following 8 years of dental treatment and caries prophylaxis, the caries increments were 11.4 (s.d. = 7.7, n = 23 subjects) and 17.1 (s.d. = 9.6, n = 39 subjects) surfaces, i.e. significantly different (t = 2.376). Significantly (t = 4.034) more fillings had been required in the high than in the low prevalence group (31.1 +/- 17.1 vs. 15.5 +/- 9.6). The "risk group" could be identified at the ages of 7 to 8 by high caries prevalence and high ratio fillings/caries increment. Social class and number of teeth accounted more for the initial caries prevalence than for the caries increment. Correlation analyses revealed a significant, but not strong (r = 0.50), association between caries prevalence at the age of 7 and increment of fillings.     

Age as a determinant of severity of dental fluorosis in children residing in areas with 0.5 and 2.5 mg fluoride per liter in drinking water

The purpose of this study was to investigate the influence of age on the severity of dental fluorosis in children exposed to drinking water with either low or high fluoride concentrations. The children selected for this study were aged 10–14 years, with 28 permanent teeth and at least 1 tooth pair with fluorosis. The children were permanent residents of districts in western Uganda with either 0.5 mg (n=33) or 2.5 mg fluoride/l in drinking water (n=186). All vestibular tooth surfaces were examined for fluorosis using the modified Thylstrup and Fejerskov (TF) index. In the high fluoride community, the proportion of teeth per child with TF scores ≥4, and ≥5 was significantly higher among children aged 13–14 years compared to those aged 10–12 years. Children’s chronological age correlated positively and significantly with the median TF scores for all teeth, including early erupting (first molars and incisors) and late erupting teeth (canines, premolars and second molars). In linear regression analyses, the median TF score for all teeth, as well as for early erupting and late erupting teeth, increased significantly with age. On the other hand, in the low fluoride community there was no significant association between age and the severity of fluorosis. This study showed a significant increase in the severity of fluorosis with increasing age in a high fluoride community, whereas no change in severity with age was observed in a low fluoride community. Received: 3 February 2000 / Accepted: 15 March 2000     

血小板血浆对人牙髓细胞增殖的影响

目的：观察血小板血浆及其细化成分对人牙髓细胞增殖的影响。方法：使用因正畸而拔除的人牙的牙髓细胞，用细胞定量测定试剂盒测定细胞增殖情况。结果：5％的多血小板血浆（platelet-rich plasma，PRP）、5％和10％的洗净血小板（washed platelet，WPLT）均明显地促进了人牙髓细胞的增殖，而且WPLT的作用较PRP更显著。乏血小板血浆（platelet-poor plasma，PPP）呈浓度依赖性地抑制了人牙髓细胞增殖，5％WPLT促进人牙髓细胞增殖的作用。结论：去除血浆成分的WPLT对培养的人牙髓细胞增殖有明显的促进作用；血浆中可能存在对抗血小板生长因子作用的因子。     

Caries experience and caries predictors--a study of Tanzanian children consuming drinking water with different fluoride concentrations

The aim of this investigation was to assess the role of predictors of caries experience among children in urban and rural areas of northern Tanzania. Children of the different communities had varying dietary habits and consumed water with varying fluoride (F) concentration. Subjects (n=256) aged 9-14 years were examined in high-F areas (3.6 mg F/l, Arusha and Arusha Meru, n=101) and low-F areas (<0.4 mg F/l, Moshi and Kibosho, n=155). Dental caries was assessed under field conditions using the decayed, missing, filled teeth (DMFT) index and the WHO criteria. The prevalence of caries was 14%. The mean DMFT score was 0.22 (n=256), the range between areas 0.07-0.66. Carious lesions were mainly observed in mandibular first molars. Logistic regression analyses indicated that subjects in the high-F and urban Arusha municipality were at a significantly higher risk of dental caries than children in the low-F areas (odds ratio [OR] 2.6). Controlling for ethnicity, children in urban areas were at higher risk for caries (OR 5.4) than children living in low-F rural Kibosho.     

Trib1 is a lipid- and myocardial infarction-associated gene that regulates hepatic lipogenesis and VLDL production in mice

Recent genome-wide association studies have identified a genetic locus at human chromosome 8q24 as having minor alleles associated with lower levels of plasma triglyceride (TG) and LDL cholesterol (LDL-C), higher levels of HDL-C, as well as decreased risk for myocardial infarction. This locus contains only one annotated gene, tribbles homolog 1 (TRIB1), which has not previously been implicated in lipoprotein metabolism. Here we demonstrate a role for Trib1 as a regulator of lipoprotein metabolism in mice. Hepatic-specific overexpression of Trib1 reduced levels of plasma TG and cholesterol by reducing VLDL production; conversely, Trib1-knockout mice showed elevated levels of plasma TG and cholesterol due to increased VLDL production. Hepatic Trib1 expression was inversely associated with the expression of key lipogenic genes and measures of lipogenesis. Thus, we provide functional evidence for what we believe to be a novel gene regulating hepatic lipogenesis and VLDL production in mice that influences plasma lipids and risk for myocardial infarction in humans.