Enhancement plaque control in preschool children by an intelligent brushing guide device.

This study aims to investigate the impact of a tooth-brushing guidance system on the enchancement of the dental plaque removal in preschool children. In this study, we selected a group of 124 healthy children in which their aged were between 3 and 5 years old following by treatment at the Pediatric Dentistry Center at Jinzhou Stomatological Hospital (JinZhou, Liaoning Province, China). We then followed up to check and identify the Turesky modification of the Quigley-Hein plaque index (TMQHPI). Study group was randomly assigned to an experimental group in which they received constantly guidance on intelligent tooth-brushing and a control group which was used by manual brushing techniques. The total numbers in each group were 62 participants that were gone under the clinical investigation for seven days. The plaque index of both groups were assessed by using a plaque display instrument and a periodontal probe for up day 28. It was shown that the experimental group had a lower average TMQHPI value (0.98 ± 0.15) in comparison with control group (1.41 ± 0.17), and this difference was statistically significant (p < 0.05). The experimental group had a significantly lower TMQHPI value (0.89 ± 0.13) on the tongue/palatal side of the anterior teeth area in comparison with control group (1.41 ± 0.17) (p < 0.05). We observed that experimental group showed significantly lower TMQHPI value (1.16 ± 0.12) on the tongue/palatal side of the posterior dental region in comparison with control group (1.70 ± 0.13) (p < 0.05). It was confirmed a significant difference in the average plaque clearance rate between the experimental and control groups (p < 0.05). Our study clearly indicates that a developed method of toothbrush guide effectively improved the removal rate of plaque compared with manual tooth-brush, specifically in hard-to-reach areas like the tongue and palate.

[Characteristics and evolution of hydrochemical compositions of freshwater lake in Tibetan plateau].

Freshwater lake of the Tibetan plateau has great ecological value and extreme vulnerability. The water samples have been collected in Daggyaima Co at an altitude of 5 080 m +/- 10 m. This study has investigated the sources, the major controlling factors of the major ions, and hydrochemical evolution trend according to the hydrochemical composition of water samples. The results showed that the major cations and anion of lake water were Ca(2+), Na(+) and HCO3(-), respectively, and the hydrochemical type was HCO3 -Ca, The total dissolved solid (TDS) was in the range of 71.2-199.8 mg x L(-1). The concentrations of EC, Ca(2+) and HCO3(-) in water samples from Southeast areas were relatively low resulted from the rich aluminum and poor calcium of geological background and the dilution effect of surface runoff. The Na(+)/(Na(+) + Ca(2+)) of water samples was 0.08-0.75, Cl(-) /(Cl(-) + HCO3(-)) was 0.11-0.35, Ca/Na was 0.58, Mg/Ca was 0.12, and HCO3/Na was 1.46, which suggested that the hydrochemical composition of the lake water was mainly controlled by silicate rock weathering based on Gibbs model and analysis of elemental stoichiometry. The minerals participated in weathering processes included plagioclase (anorthite, albite), potassium feldspar, biotite, calcite, dolomite, gypsum, rock salt, etc. The average value of K/Na was 0.059, indicating the weathering level of potassium feldspar was relatively low. The saturation index (SI) of calcite, dolomite, gypsum, quartz and hematite contained in the lake was higher than zero, while the SI of rock salt was lower than 0, revealing the trend that the freshwater lake is turning into salt water lake in Tibetan Plateau.