[The effect of fluoride on adhesion of Streptococcus mutans and Streptococcus sanguis on the dental pure titanium surface].

Purpose: This study was to investigate the effect of fluoride on adhesion of Streptococcus mutans and Streptococcus sanguis on the dental pure titanium surface.

Methods: The adhesion of Streptococcus mutans and Streptococcus sanguis on the dental pure titanium surface were examined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay after soaked in artificial saliva containing different concentrations of sodium fluoride for 24 h. Then the surface roughness and surface morphology of the pure titanium were analyzed by atomic force microscope after bacterial adhesion experiments.

[The effect of epigallocatechin gallate (EGCG) on the surface properties of nickel-chromium dental casting alloys after electrochemical corrosion].

Purpose: To investigate the effect of epigallocatechin gallate (EGCG) on the surface properties of nickel-chromium dental alloys after electrochemical corrosion.

Methods: The surface morphology and surface structure of nickel-chromium dental alloys were examined by stereomicroscope and scanning electron microscopy before and after electrochemical tests in 0 g/L and 1.0 g/L EGCG artificial saliva.

[Evaluation of masticatory efficiency of lingualized occlusal complete denture].

Purpose: To compare the masticatory efficiency of lingualized occlusal complete denture with that of semi-anatomical occlusal complete denture.

Methods: Sixty cases with flat or depressed residual ridges were selected from 2009 to 2011. After randomly divided into two groups, the patients were treated with lingualized and semi-anatomical occlusal complete dentures, respectively.

[Study of the appearance difference of lower complete denture between functional and anatomic impression techniques].

Purpose: To compare the difference in oblique external ridge, oblique internal ridge and alveolar process crest of lower complete denture base made through functional impression and anatomic impression techniques.

Methods: Fifteen patients were chosen to treat with two kinds of complete dentures through functional impression and anatomic impression technique respectively. 3D laser scanner was used to scan the three-dimensional model of the denture base and the differences of the surface structural between two techniques in alveolar process crest, external and internal oblique ridges were analyzed, using paired t test with SPSS 12.

[Study on cytotoxicity of three kinds of dental ceramic alloys on L929 mouse fibroblasts in vitro].

Purpose: To investigate the cytotoxicity in vitro of three kinds of dental ceramic alloys on L929 mouse fibroblasts.

Methods: CCK-8 assay was a quick method to study the cell relative proliferation rate or cytotoxicity. L929 mouse fibroblasts were used to detect the cell relative proliferation rate of the three kinds of dental ceramic alloys(NiCr,CoCr and golden alloys containing 58% of gold) by CCK-8 assay.

[Stress analysis of mandibular second premolar restored with fiber post-core with different shapes and diameters].

Purpose: To evaluate the stress distribution of mandibular second premolar restored with different shapes and diameters fiber post-core.

Methods: A load of 200N was distributed to the finite element model of mandibular second premolar restored with three different shapes (column post, cone post and trapezium post) and three different diameters(1/2,1/3 and 1/4 of root diameter) fiber post-core in vertical and lateral ( 45 degrees ) direction, and software of "Nastran" was applied to analyze the three-dimensional finite element distribution of stress respectively.

Results: Irrespective of the shapes, there was no significant change of stress distribution with the increase of post diameter.

[The dental caries prevalence of primary teeth in 789 five-year-old children in Shanghai].

Objective: The aim of this study was to observe the change of the prevalence of five-year-old children's dental caries for 10 years in Shanghai and to establish a related policy to provide a basis for the government.

Methods: The sampling method was multi-stage, stratified, adqulis capacity and whole flock in this study. The method of third national survey for oral health was used.

[Cytotoxicity of three kinds of temporary crown and bridge materials on mouse fibroblasts in vitro].

Purpose: This study was to investigate the cytotoxicity in vitro of three kinds of common temporary crown and bridge materials, i.e.,self-curing resin, heat-curing resin, and DMG-TEMP bi-acrylic composite.